United States 

Department of 

Agriculture 

Forest Service 

Southern Forest 

Experiment Station 

New Orleans, 

Louisiana 

Baho de Oro Natural Area 

Luquillo Mountains, 

Puerto Rico 

General Technical Report 

SO-1 11 

Peter L. Weaver 

September 1994 
The 745-ha Bano de Oro Natural Area, established by the U.S. 

Department of Agriculture, Forest Service, in 1949, was made part 

of the Luquillo Experimental Forest Biosphere Reserve in 1976. 

The Natural Area, situated at elevations between 245 and 1,025 m 

in the wettest part of Puerto Rico, encompasses four major forest 

types that are free of human disturbance. Past and current 

research in the Bafio de Oro Natural Area is summarized in this 

document to serve as a basis for further investigation. The current 

state of knowledge regarding the environment (i.e., geology, physiography, soils, climate, hydrology, flora, and fauna) is outlined. 

The author is grateful to numerous researchers for assistance in the completion of this report. Manuel Velez and his graduate students conducted the survey 

of the fauna in the Bafio de Oro. James A. Ackerman, Ned Fetcher, Charlotte M. 

Taylor, Janice Voltzow, Lawrence R. Walker, and Sandra Guzman of the University of Puerto Rico Biology Department as well as Clyde E. Asbury, D. Jean 

Lodge, William T. Lawrence, John A. Parrotta, and Robert B. Waide of the 

Center for Energy and Environment Research (CEER) provided information for 

the ongoing Minority Research Program in the dwarf forest near the Baiio de 

Oro. Several others provided information on specific topics: Clyde E. Asbury, 

stream sampling; Sonia Borges, University of Puerto Rico, Mayaguez, earthworms; Allan Drew, State University of New York, College of Forestry and 

Environmental Science, ring formation in C~rilla racemiflora; Miguel A. Garcia, 

University of Puerto Rico, Rio Piedras, anoline lizards; Rafael Joglar, University 

of Puerto Rico, Rio Piedras, frog density and diversity; and Joe Wunderle, 

International Institute of Tropical Forestry, data from the phenology trail. Loren 

Huffaker of the Carribean National Forest devised an updated classification of 

the soils. Russell M. Burns, U.S. Department of Agriculture, Forest Service, 

Washington Office, and Margaret S. Devall, U.S. Department of Agriculture, 

Forest Service, Southern Forest Experiment Station, New Orleans, reviewed the 

entire document. This study was made possible by a grant from the United 

States Man and the Biosphere (MAB) program. The collaboration of the University of Puerto Rico is recognized. 

Cover: 

Overview of Bafio de Oro Natural Area from the Yokahu Tower 
BACKGROUND INFORMATION ..................................... 1 

Introduction ....................................................... 1 

Administrative Details ............................................. 2 

Historical Perspective .............................................. 2 

Objectives ......................................................... 3 

OVERVIEW OF MAJOR FOREST RESEARCH ......................... 3 

THE B~O DE OR0 NATURAL AREA ............................... 4 

Geology ........................................................... 4 

Physiography .................................................. 6 

Soils .............................................................. 7 

Climate ........................................................... 8 

Precipitation .................................................... 10 

Temperature .................................................. 10 

Relative Humidity ............................................... 11 

Wind Velocity and Direction ...................................... 11 

Cloud Cover and Solar Insolation .................................. 11 

Hurricanes ...................................................... 12 

Hydrology ......................................................... 13 

FLORA ............................................................. 13 

Major Forest Qpes ................................................ 13 

Other Vegetation Qpes ............................................. 14 

Tree Species Distribution ............................................ 14 

Pico del Oeste Flora ................................................ 14 

Vascular Plants .................................................. 14 

Mosses ......................................................... 19 

Leafy Hepaticae .............................................. 19 

Algae ........................................................... 19 

Other Dwarf Forest Studies ...................................... 19 

Vegetation Gradient ................................................ 29 

Current Research Activities ......................................... 31 

Long-term Monitoring on TR-I .................................... 31 

Phenology Trail .................................................. 37 

Ring Formation in Cyrilla racemiflora ............................. 37 

Minority Research Program ...................................... 37 

Water Chemistry ................................................ 38 

FAUNA ............................................................. 39 

Vertebrates ........................................................ 39 

Bat Study ....................................................... 44 

Black Rat Study ................................................. 44 

Puerto Rican Parrot Studies ...................................... 45 

Other Bird Species Studies ....................................... 46 

Anoline Lizard Studies ............................................ 46 

Frog Diversity Study ............................................. 47 

Invertebrates ...................................................... 47 

Earthworm Study ............................................... 47 

Studies of Other Organisms ....................................... 47 

Classified Plant and Animal Species ................................. 47 

FUTURE ACTIVITIES .............................................. 47 

LITERATURE CITED .............................................. 48 

APPENDIXTABLE 1 ................................................ 55 
Bdo de Oro Natwd Area 

Luquillo sins herto Rico 

Peter L. Weaver 

INFORrnTION 

Introduction. 

The purpose of this report is to compile relevant 

environmental information on the Baiio de Oro 

Research Natural Area (Baiio de Oro) in Puerto Rico. 

Because research in the Luquillo Mountains has been 

extensive, much of the data was derived from published Research Areas (RNA's) are tracts On which sources. Original inventories of fauna and flora, how- natural features and processes predominate and which 

ever, have been included to complement other informaare preserved for scientific or educational purposes tion. Subsequent research will undoubtedly result in 

(Federal Committee On Research Natural 1968)' the identification of additional species and will require The areas need not be pristine because this requisite supplements to this text. would preclude many ecosystems that have suffered 

some live1 of human disturbance and which no longer 

exist in an undisturbed state (Dyrness and others 

1975). I-Iowever, if disturbed ecosystems are designated 

as RNA's, protective measures should be undertaken to 

restore them to their original condition through natural processes. Research Natural Areas may vary in size 

from a few to several thousand hectares and preferably 

are surroundedtd, or buffered, by other protected land. 

Research Natural Areas are established to provide a 

baseline for comparison with areas influenced by 

human activity (Moir 1972). Research Natural Areas 

may include typical or unusual fauna and flora or may 

represent outstanding geologic, pedologic, or aquatic 

features or processes. They constitute reserves for the 

protection of rare or endangered organisms and serve 

as reservoirs for the conservation of genetic resources. 

Research on RNA's must be essentially nonmanipulative and reasonably consistent with the purpose and 

character of the surrounding land (Federal Committee 

on Research Natural Areas 1968). Deliberate manipulation simulating natural processes is occasionally 

allowed and, in some instances, encouraged to restore 

communities or organisms to their original state 

(Dyrness and others 1975). 

It is imperative that the U.S. Department of Agriculture, Forest Service, exercise control over all research 

activities to assure that they comply with existing 

guidelines and do not negatively impact the resources 

in the RNA. The Forest Service must grant permission 

for all research activities and review them regularly. 

Research Natural Areas managed under the above 

widelines serve scientists, resource managers, and the 

level. Area. 

Peter L. Weaver is a research forester at the International Institute of Tropical Forestry, U.S. Department of Agriculture, Forest Service, Rio 

Piedras, PR 00928-2500. In cooperation with: University of Puerto Rico, Rio Piedras, PR 00936-4984. 
Administrative Details 

At the end of the Spanish-American War in 1898, the 

Crown lands of Puerto Rico passed from Spain to the 

United States. In 1903, the United States government 

proclaimed these lands as the Luquillo Forest Reserve, 

and since 1917 they have been managed by the Forest 

Service. In 1935, the Luquillo Forest Reserve was 

renamed the Caribbean National Forest (CNF) to 

include Federally purchased lands elsewhere in Puerto 

Rico. In 1939, the 'I'ropical Forest Experiment Station 

(now the International Institute of Tropical Forestry) 

was established. In 1956, the CNF was also administratively designated as the Luquillo Experimental 

Forest (LEF) to recognize the growing importance of 

research in the forest. Although the terms CNF and 

LEF refer to the same land, the objectives of the Forest 

Service units that work in the forest are distinct. The 

CNF is responsible for management of the forest, or 

making it productive by demonstrating forest practices 

in a tropical setting. The LEF is responsible for farestry and forest-related ecological research. Throughout this publication this area will be referred to as the 

LEF. 

The 745-ha Baiio de Oro (located at 18°17'30w N. 

latitude and 65"45'3OW FV. longitude) in the Luquillo 

Mountains (fig. 1) was established by the Forest Service in 1949. Although comparatively small in size, the 

Baiio de Oro encompasses the boundary areas of four 

municipalities: Rio Grande, Luquillo, Fajardo, and 

Ceiba. 

The Baiio de Oro was selected as an RNA for several 

reasons: (I) the land was surrounded by other Forest 

Service lands, (2) the terrain was unmodified by 

human activity, (3) the unit contained representative 

areas of the four forest types that characterize the 

Luquillo Mountains, and (4) the unit contained populations of the endemic Puerto Rican parrot (Amazona 

vittata), at that time confined to the upper slopes of the 

Luquillo Mountains. Since its proclamation, the Baiio 

de Oro has been managed in accordance with RNA 

guidelines. In 1968, it was listed in a national directory 

of more than 300 RNA's set aside on Federal lands 

(Federal Committee on Research Natural Areas 1968). 

In 1976, the entire LEF was designated as part of the 

international network of Biosphere Reserves (Lugo 

1987). 

The Baiio de Oro is roughly diamond shaped and 

oriented in line with the cardinal directions (fig. 1). The 

southwestern boundary extends along the ridge from 

the intersection of the Molindero and Pico del Este 

Roads to Pico de1 Oeste, approximately paralleling the 

Pic0 del Este Road, which was finished in 1962. The 

lower half of the northwestern boundary is about 

100 m east of the Molindero Road. Where the northern 

part of the Molindero Road trends west, the boundary 

continues northeast on the same ridge intersecting the 

Rio de la Mina at a 450-m elevation. From this point, 

the boundary is the Rio de la Mina to its confluence 

with the Rio Mameyes. A primitive trail parallels the 

Rio de la Mina and terminates at the Rio Mameyes. The 

northeastern boundary is the Rio Mameyes and its 

eastern fork for nearly half its distance after which the 

boundary follows along a ridge to a local high point at 

an elevation of 675 m and then descends along a divide 

to the Rio Fajardo. About 90 percent of the southeastern boundary is the eastern tributary of the Rio 

Fajardo from its confluence with the Rio Fajardo to its 

source just below Pico del Oeste. The remainder of the 

boundary follows the ravine above the river to Pico del 

Oeste. 

Expansion of the Baiio de Om by more than 40 

percent to encompass a total of 1,180 ha is being considered in the current forest management plan. The proposed new areas include Pico del Este, one of the 

wettest locales on the Island, areas above a 750-m 

elevation east of Pico del Este, and areas above a 700-m 

elevation south of the road to Pico del Este (fg. 1). A 

small area known locally as the "valley of the giants" 

because of the many large trees found there is also part 

of the proposed addition. It extends down to a 640-m 

elevation in the Icacos Valley, south of the Pico del Este 

road. 

Historical Perspective 

Land clearing by pre-Columbian Indians appears to 

have affected only a small area in Puerto Rico, mainly 

on the coastal plain Wadsworth 1950a). Land clearing 

by settlers began early in the northeastern part of the 

Island but did not ascend the slopes of the Luquillo 

Mountains for many years because Carib Indians lived 

there. Before 1876, the Spanish Crown did not grant 

concessions to people willing to settle in the mountains. 

In 1876, the Crown established forest reserves in 

Puerto Rico, including the LEF (Brown and others 

1983). Subsequently, concessions to some mountainous 

lands were granted, but inaccessibility and the poor 

quality of the soil caused the core of the Luquillo 

Mountains to remain Crown land and to remain forested until the Treaty of Paris in 1898. In 1903, conservation of the region began with the proclamation of the 

Luquillo Mountains as a forest reserve. 

The search for gold in the Luquillo Mountains was 

carried on from 1513 until the late 19th century 

Wadsworth 1950a, 1970). During the 19th century, 

gold was discovered near the confluence of the Rio de la 

Mina and Rio Mameyes where the Luquillo Mine and 

the Monserrate Mine operated for a few years (Cardona 

1984, Cox and Briggs 1973). Penetration into the upper 

slopes of the Luquillo Mountains via foot trails, however, was infrequent as late as 1905 (Wadsworth 1970). 

The foot trail to El Yunque was virtually impassable 

until a horse trail was finished in 1922. Route 191 from 
ROUTE 

186 

ROUTE 

191 

EL VERDE 

NATURAL AREA 

ROUTE 

PROPOSED BOUNDARY 

EXPANSION OF NATURAL 

* EL VERDE FIELD STATION 

ROUTE A STREAM GAUGING STATION 

0 - I2km 191 

u 

C -119 WRECK 

Figure 1.- Location of the Bario de Om Natural Area within the Luquillo Experimental Forest. Climatic stations and reference sites are indicated. 

the town of Mameyes to Rio Blanco, initiated in 1926, 

was not completed until 1942. Only 7 years later, the 

Forest Service established the Baiio de Oro, located 

about 1 km east of the highway. At that time, less than 

1 percent of Puerto Rico's land surface remained in 

pristine condition (Wadsworth 1950b), and the LEF, 

the largest contiguous undisturbed forest on the 

Puerto Rican mainland, surrounded the Baiio de Oro. 

There is no evidence of previous exploration or scientific collections in the Baiio de Oro. Moreover, there is 

no evidence of logging, hunting, or diversion of water 

resources. Scattered banana plants and the remains of 

a house, however, are located near the confluence of the 

Rio de la Mina and Rio Mameyes, suggesting that the 

area had been occupied at least on an interim basis for 

some time. 

Objectives 

The purpose of this report is to compile existing 

knowledge of the Baiio de Oro to serve as a basis for 

further investigations. The main effort is to call attention to the nature of existing literature rather than to 

review it in detail. Research activities conducted within 

the Baiio.de Oro are emphasized along with relevant 

ecological information gathered in the surrounding forests. All plant and animal species encountered within 

the Baiio de Oro are listed in tables. 

OVERVIEW OF MAJOR 

FOREST RIESEXRCH 

Numerous studies of the climate, flora, fauna, and 

ecology of the Luquillo Mountains have already been 

completed, ranking the LEF among the best studied 

tropical forests in the world. The citation of a few major 

references will indicate the extent of the investigations. 

A bibliography with nearly 2,000 entries on Puerto 

Rican forestry research including texts, journal and 

newspaper articles, theses, proceedings, and reports, 

most written between the early 1880's and 1978, was 

compiled by the Institute of Tropical Forestry (now the 

International Institute of Tropical Forestry) library 

staff (Mosquera and Feheley 1983). Summarizing past 

research in the Luquillo Mountains, Wadsworth (1970) 
Effects of Hurricane Hugo in the BaiLo de Om Natural Area. 

cited 118 references on the geography, climatology, geology, flora, fauna, ecology, archeology, agriculture, and 

forestry of the Luquillo Mountains. Both works also 

contain information on early botanical exploration of 

the mountains. 

From 1939 through 1963, issues of the "Caribbean 

Forester" highlighted early Forest Service investigations in the mountains. Between the early 1960's and 

mid-1970's, the arborescent vegetation of Puerto Rico 

and the U.S. Virgin Islands was described based on 

past research and numerous field observations (Little 

and others 1974, Little and Wadsworth 1964). 

A compendium of information on forest plants, animals, and the environment, before and after radiation, 

was summarized for the El Verde tabonuco forest 

located only 5 km northwest of the Baiio de Oro (Odum 

and Pigeon 1970). In 1983, the history of LEF research 

and opportunities for additional investigations were 

outlined (Brown and others 1983). In 1987, long-term 

ecological research dealing with the fauna, flora, and 

watershed dynamics was initiated in the Bisley watersheds only 2 km northeast of the Bafio de Oro (Scatena 

1989). Moreover, current research activities in the LEF 

are summarized in the "Annual Letter" of the International Institute of Tropical Forestry. 

Beginning in 1966, and extending through the 

mid-1970's, the staff of the Arnold Arboretum (located 

in Cambridge, Massachusetts) studied the Bafio de 

Oro's dwarf forest on Pico del Oeste. The results 

appeared as 17 research papers in the "Journal of the 

Arnold Arboretum." Study of the Puerto Rican parrot, 

whose numbers had declined rapidly during the 1960's, 

was initiated in 1968 throughout the LEF (Snyder and 

others 1987). Parrot nesting boxes were installed at two 

locations in the upper reaches of the Baf-10 de Oro 

during the 1970's (fig. 2) as part of the research program. Parrot observations and implementation of the 

parrot recovery program continue today. 

Studies conducted in the Baiio de Oro Natural Area 

are covered in more detail in subsequent chapters. To 

facilitate future investigations of the flora and fauna in 

the Bafio de Oro, a list of select references has been 

prepared (appendix table 1). 

THE BA&O DE OR0 NATURAL AREA 

The information provided in this section pertains 

mainly to the Bafio de Oro. Relevant data from studies 

elsewhere in the LEF, particularly with reference to 

climate and vegetation, are also included. 

Geology 

The geology of the Caribbean area and Puerto Rico is 

complex and has been a source of controversy among 

authors who favored explanations based on theories in 

vogue at the time. The summits of the Luquillo Mountains were first described as Cretaceous monodnocks, 

or residuals of old topography standing above a plain of 

subaerial erosion (Meyerhoff 1933). This interpretation 

was questioned (Mitchell 1954) because uparching and 
PTEROCARPUS 

STAND 

WATERSHED 

PERMANENT PLOT (TR-I) 

0 ALPINE MEADOW 

a TEMPORARY PLOTS 

0 THRASHER NEST SITES 

@ PARROT RESEARCH PLOTS 

0- 0UNIVERSITY OF PUERTO RICO 

FAUNAL SURVEY STATIONS 

MINORITY RESEARCH PLOTS 

Figure 2.-Location of research plots in the Bario de Om Natural Area. The plots surveyed in the University of Puerto Rico faunal 

study are numbered 1 through 13. 

faulting provided a more logical explanation for the 

peak areas than erosion alone. In a summary of the 

Island's geologic history (Beinroth 1969), Puerto Rico's 

origin was attributed to a series of submarine volcanos 

formed during the Cretaceous Period. At the beginning 

of the Tertiary Period, mountain building and uplift 

occurred, followed by weathering and erosion, which 

reduced the Island to low hills. The central portion was 

then pushed upward, coastal areas sank, and limestone 

was deposited along the coasts. By the Miocene epoch, 

Puerto Rico was conceived as a nearly level plain with 

meandering streams. The entire area was uplifted 

again to over 1,000 m in elevation, and a new erosive 

cycle was initiated. 

Recent explanations of geologic history in the Caribbean area rely on plate tectonics but still reflect controversy. North America, South America, and Africa 

began to diverge about 175 million years ago through a 

series of rifting episodes that created the Gulf of Mexico and the Caribbean Sea (Dillon and others 1987-88). 

Numerous geologic events, previously considered to be a 

variety of independent island arc systems formed at 

different places and times, now appear as a sequence of 

plate events reflecting a single great Caribbean Island 

arc system that was constructed in the Pacific and 

migrated into the Atlantic (Burke 1988). A simple 

model involving the rotation of a tectonic block containing Puerto Rico within the broad strike-slip boundary 

of the Caribbean plate is proposed to account for the 

Island's major tectonic features (Masson and Scanlon 

1991). 

The Baiio de Oro is underlain by a complexly faulted 

and folded terrain composed chiefly of Cretaceous volcanic rocks, subordinate Cretaceous and/or Tertiary 

intrusive bodies, and minor lower Tertiary volcanic and 

sedimentary rocks (Seiders 1971a). The underlying 

rocks are largely tuff, volcanic breccia, and tuffaceous 

sandstone and siltstone, chiefly marine (Cox and 

Briggs 1973). Lava probably constitutes more than 15 

percent of the 10,000 m or deeper section and is chiefly 

concentrated in the lower part and locally in the middle 

part. Limestone occurs sporadically in the upper part 

of the section. In the Bafio de Oro, five major geologic 

mapping units have been identified (fig. 3). Of the 

stratified deposits, unnamed volcanoclastic rocks, 

which included marine-deposited andesitic to what is 

thought to be basaltic volcanic sandstone, and fine volcanic breccia with subordinate cherty mudstone, 

occupy slightly more than half the area. Cherty 

mudstone lies in a thin strip in the southeastern 
INTRUSIVE ROCKS 

.QUARTZ DlORlTE (TQD) 

240 ha (32.2 %) 

DlORlTE (TD) 

25 ha (3.4 '10) 

STRATIFIED ROCKS 

TABONUCO FORMATION (KT) 

32 ha (4.3 %) 

>:;ri,,.> UNNAMED VOLCANOCLASTIC ROCKS (KU) 

387 ha' (51.9 '10) 

MUDSTONE MEMBER (KUM) 

61 ha (8.2 '10) 

Figure 3. - Geologic map of the Bario de Oro Natural Area (Seiders 1971a, 1971b). 

portion. The tabonuco formation, composed of andesitic to basaltic volcanic sandstone (about 60 percent), 

mudstone (about 30 percent), and volcanic breccia and 

conglomerate (about 10 percent), lies along the north 

and northwestern pheriphery. 

Of the intrusive rocks, nearly one-third of the area is 

composed of quartz diorite in which quartz accounts 

for about a quarter of the mineral composition. A zone 

of contact metamorphism surrounds the quartz diorite, 

which exhibits metamorphosed volcanoclastic rocks 

typically harder and darker than unmetamorphosed 

equivalents. Hornblende diorite and quartz diorite are 

also found in the east central part of the Bario de Oro. 

More detailed descriptions of the mapping units are 

provided by Seiders (1971b). 

Physiography 

The Baiio de Oro measures 3.55 km from north to 

south and 4.15 km from east to west (fig. 4). Total relief 

is 780 m, ranging from 1,025 m on Pico del Oeste on 

the south to 245 m in elevation where the Rio Marneyes 

flows out to the north. The average gradient between 

the high and low points in the watershed is 220 m/km. 

Two main ridges are evident within the Baiio de Oro. 

The first trends northeast from Pico del Oeste to a 

685-m high point on the northeastern border of Bario 

de Oro, never descending below a 490-m elevation. This 

ridge separates the upper portions of the Rio Mameyes 

and Rio Fajardo watersheds. The Rio Fajardo flows out 

the eastern border of the B&o de Oro at an elevation of 

350 m. The second ridge, trending northwest from Pico 

del Oeste along Route 930, descends gradually to about 

700 m at the western edge of the Baiio de Oro. 

Nearly 71 percent of the Baiio de Oro lies between 

400 and 700 m in elevation, with about 11 percent 

< 400 m and 18 percent > 700 m in elevation (fig. 4). The 

terrain is steep. About 47 percent of the 745 ha is in 

slopes >60 percent, with 48 percent in slopes between 

30 and 60 percent, and only 5 percent in slopes ~30 

percent (fig. 5). 
'PICO DEL OESTE 

Figure 4.- Topographic map of the Baa de On, Natural Area. 

Soils 

Most of the Baiio de Oro is inaccessible, and only 

limited information is available regarding soils. 

Ultisols, occupying about one-third of the 745 ha, and 

Inceptisols, occupying the remaining areas, are the 

only major soil orders that have been identified (fig. 5). 

In general, the Ultisols are confined to the largest river 

valleys below 600 m in elevation. The Inceptisols, in 

contrast, occupy the main ridges and adjacent terrain 

down to 300 m in elevation. 

The Soil Conservation Service tentatively classified 

the entire area as the Los Guineos-Guayabota rock 

land association (Boccheciamp 1977). This area is characterized by shallow to deep, well-drained to poorly 

drained, strongly sloping to very steep soils on volcanic 

uplands in tropical rain forests. The specific units 

recognized were Guayabota-Ciales-Picacho association 

on very steep land, Los Guineos-Yunque-Stoney rock 

land association on steep land, and the UtuadoPicacho-Stony rock land association on very steep land. 

Subsequently, an effort was made to develop soil 

mapping units for the LEF (fig. 6). The largest unit 

classified was the Yunque-Los Guineous Complex, 

occupying nearly 40 percent of the Baiio de Oro (fig. 6). 

The next largest unit, accounting for 25 percent of the 

Baiio de Oro, was the Picacho-Utuado Complex. 

Soils of Pico del Oeste's dwarf forest, designated as 

lithic tropaquents, have a mucklike surface 25 to 30 cm 

thick with organic matter up to 50 percent (Lyford 

1969). A distinctly mottled gray gleyed horizon lies 

below, and this is underlain by massive, plastic, nonsticky clay with weathered rock fragments in places. 

The pH throughout the horizons ranges between 
SOILS 

INCEPTISOLS - 497 ha (67.7 %) 

ULTISOLS - 248 ha (33.3 O/O) 

SLOPES 

0 -30°/0, 35 ha (4.70/0) 

.......... ......... 31-60 O/o, 360 (48.3 Ole) 

Figure 5.-Soil orders and slopes in the Baib de Oro Natural Area (Institute of %pica1 Forestry files). 

4.3 and 4.9. Seepage water entered from all horizons 

when trenches were dug into the soil. 

The roots of dwarf forest vegetation are found in four 

general habitats: the soil, immediately above the soil in 

cryptogams or litter, appressed to trunks and 

branches, or hanging freely (Gill 1969). About 80 to 90 

percent of the woody roots are just under the forest 

litter or within 2 to 10 cm of the soil surface. Tree 

stems are covered not only with epiphytes and roots but 

also with a soillike material high in organic matter 

derived from the decomposition of epiphytic material 

and trapped leaves. 

Climate 

Puerto Rico, situated in the northeast trade wind 

belt about 1,800 km from the Equator, has a tropical 

marine climate (Calvesbert 1970). The longest day 

(about 13.2 hours) varies only about 2 hours in length 

from the shortest day (about 11.0 hours). The LEF, 

located in the northeastern part of the Island, presents 

the first obstacle to the trade winds crossing the 

Atlantic. The abrupt elevational gradient from the base 

of the mountains to the summits profoundly influences 

local climate. 

Four major systems may be superimposed on the 

trade wind regime influencing local weather (Odum 

and others 1970): polar troughs (temperate, low pressure troughs moving southeastward); easterly waves 

(low pressure troughs moving westward); shear lines 

(remnants of cold fronts that reach tropical latitudes in 

the winter); and tropical storms (low pressure centers, 

with closed isobars and circular converging airflow, 

moving westward). Tropical storms, particularly if moving slowly, may cause torrential rainfalls (Calvesbert 

1970). The Island is also located within the hurricane 

belt of the Caribbean and occasionally experiences the 

high winds and heavy rains that accompany these 

storms. 

No permanent climatic stations are located within 

the Bafio de Oro. Climatic data are available from one 

temporary station situated on Pico del Oeste and from 

six other LEF sites located at short distances from the 

Bafio de Oro (table 1) (fig. 1). Station records vary with 
PICACHO - UTUADO COMPLEX 

5 TO 40 '10 SLOPES 

Figure 6.- Soil mapping units in the Bario de Om Natural Area (Huffaker [In press]). 

able 1. -Mean annual climatic data for several sites in and around the Bario de Om Natural Area* 

Relative Site Solar Elevation Rainfall Temperature humidity radiation 

Meters Millimeters "C Percent 1 day+ 

Catalina* 150 2450 23.9 88 .... B 

Sabana 4 300 35609 21.7* 79* .... Bisley 350 3000** .... .... .... La Minatt 715 4600 21.1 .... .... Pico del Oeste* 1036 4530 18.6 98 262 

Pico del Este 1050 44500% 18.70s 9891 .... El Yunque* 1065 4000 18.3 98 262 

*Dates and durations of records vary by site and parameter. See figure 1 for locations of climate 

stations. 

tl = langley = 1 calorie/cm2. 

*Record 1958-62 (Briscoe 1966). 

SBlank field indicates missing data. 

?Crow and Weaver 1977. 

**Record 1973-79 (Snyder and others 1987) and 1985-87 (Bosch, unpublished) cited by Scatena 

1989. 

ttword 1935-43 (Wadsworth 1948). 

*Record 3/1/66 to 2/28/67 except relative humidity that was measured from 7 to 10166 and 12/66 to 

2/67 (Baynton 1968). 

sPRecord 1970-82 (U.S. Department of Commerce 1970-82). 

q'BRecord 11/68 to 6/69 Weaver 1972b). 
regard to data collected, years sampled, and duration of 

measurements. They indicate trends, but comparisons 

among sites are tenuous. Data from most of the permanent and temporary climatic stations in and around the 

Luquillo Mountains were graphed and summarized in 

a previous report (Brown and others 1983). Salient 

observations from that report have been incorporated 

into the following text on climate. 

Precipitation. -Much of Puerto Rico's rainfall is 

orographic, caused by the ascent of moisture-laden 

trade winds over mountain barriers (Calvesbert 1970). 

At Catalina, Sabana 4, and Bisley, between 150 and 

350 m in elevation, mean rainfall varies between 2,450 

and 3,560 mmlyr (table 1). The four remaining sites, 

located at 715- to 1,065-m elevations, south to west of 

the Baiio de Oro, average 24,000 mm/yr. 

Rainfall fluctuates considerably from year to year 

(Wadsworth 1948, 1970). At the La Mina station, the 

9-yr mean of 4,600 mmlyr was exceeded twice by more 

than 37 percent, and during 1 year, it was 20 percent 

below the mean. Similar fluctuations in annual rainfall 

were evident from coefficients of variation between 15 

and 38 percent for other climatic stations in and adjacent to the Luquillo Mountains (Brown and others 

1983). 

Rainfall also varies during the year (fig. 7). At Pico 

del Este and La Mina, February, March, and April are 

drier than the remaining months. The wettest months 

for Pico del Este are May, October, and November; the 

wettest months for la Mina are May and November. 

The drier months of February and March and the 

wetter month of May also characterize other climatic 

stations in and around the Luquillo Forest (Brown and 

others 1983). The highest recorded daily rainfall for the 

LEF, 485 mm, was observed during May on Pico del 

Este (Weaver 1972a). 

Other informative rainfall data were summarized for 

the La Mina station (Brown and others 1983, Wadsworth 1948). Fifty days out of the year, la Mina received 

>2.54 cm (1 inch) of rainfall. Typical rainfalls, however, 

lasted 0.5 hour, delivered 3 mm of rain, and occurred 

1,625 times per year. The maximum rainfall recorded 

for 1 month was 1,030 mm. 

The total duration of rainfall events varied during 

the year. The longest durations of rainfall occurred 

from November to January and in June, coinciding 

with periods of lower monthly rainfall. This indicates 

that during these months storm events are longer but 

of lower intensity. Short durations of rainfall occurred 

during July through October coinciding with periods of 

higher rainfall and indicating greater intensity of 

storms. The total duration of rainy weather during the 

year was about 22 days, or proportionately about 6 

percent of the year. About 55 percent of this rain 

occurred between 6 a.m. and 6 p.m. 

Hail is a relatively rare event in Puerto Rico, 

although incomplete records and personal accounts 

indicate that it has fallen at some time virtually everywhere (Calvesbert 1970). During February 1969, a hailstorm lasting about 15 minutes occurred on Pico del 

Este (author, personal observation). The hailstones 

were relatively small, averaging about 0.5 cm in size. 

Zkmperature. - Mean temperatures in Puerto Rico 

characteristically have little variation between the 

warmest and coolest months, and between years (Calvesbert 1970). Mean annual temperature decreases 

from 22 to 18 "C with ascent from 300 to 1,065 m in 

elevation in the Luquillo Mountains (table 1). At 

Sabana 4, the mean annual temperature varies from 21 

"C between December and March to 24 OC in August 

and September (Briscoe 1966). Mean annual temperatures on El Yunque and Pico del Este vary from 17 or 

PIC0 DEL ESTE LA MlNA CATALINA 

4,450 rnm/yr 4,600 rnmlyr 2,450 rnmlyr 

18.7 OC 21.1 OC 23.9 OC 

1,050 m 715 rn 150 m 

Or: O C O C 

111110 

OJFMAM JJASOND 

0-0 

JFMAMJJASOND 

MONTH MONTH MONTH 

Figure 7.- Climatic diagrams for Pico &l Este (U.S. Department of Commerce 1970-82), La Mina (Wadsworth 1948), and Catalina (Briscoe 

1966). Mottled areas indicate rainfall >I00 mmlmonth, and striped areas indicate a water surplus. 
18 "C between December and March to 19 or 20 "C 

between August and October (Briscoe 1966, U.S. 

Department of Commerce 1970-82). Diurnal temperature variation and temperature range in any given 

month are larger at lower elevations than at higher 

elevations (Brown and others 1983). 

On Pico del Oeste, the highest and lowest recorded 

temperatures in 1966-67 were 26 and 13 "C (Baynton 

1968). These temperatures corroborate observations on 

Pico del Este (author, personal observation). One might 

speculate that the maximum range of temperatures 

experienced in the B&o de Oro lies between 10 "C at 

the summits and slightly more than 30 "C at the lowest 

elevation. Freezing temperatures are unknown anywhere in Puerto Rico (Calvesbert 1970). 

Relative Humidity. -The dewpoint temperature 

varies little over Puerto Rico, indicating that the overlying air mass is fairly constant with regard to moisture content during the year (Calvesbert 1970). For 

summit locations in the LEF, the mean annual relative 

humidity is >98 percent (table 1). Mean monthly relative humidity at El Yunque is near 100 percent for all 

months except February, when it decreases to about 90 

percent. At lower elevations, Catalina and Sabana 4, 

the mean annual relative humidity varies between 79 

and 88 percent. Individual mean monthly values range 

between 76 and 92 percent, with lows in March and 

highs in September through November (Brown and 

others 1983). 

The diurnal variation in relative humidity at El Yunque is slight in comparison to that of the Catalina and 

Sabana 4 locations. At El Yunque, it is at or near 100 

percent during the evening hours (from 6 p.m. to 8 

a.m.). The low is at 1 p.m., when it averages about 95 

percent. At Catalina and gabana 4, the relative humidity is near 95 percent during the evening hours. During 

daylight hours, it decreases to 75 percent at Catalina 

and 70 percent at Sabana 4, at 2 p.m. and 1 p.m., 

respectively. 

Wind Velocity and Direction. -The steadiness of 

the trade winds, blowing mostly from an easterly direction, is the outstanding feature of wind in Puerto Rico 

(Calvesbert 1970). On El Yunque, the prevailing mean 

monthly wind direction is from the northeast. In January and September, however, winds are from the south, 

and in December, from the east. In contrast, at the 

base of the mountains in Catalina, winds are more 

variable, blowing from the south in January, from the 

east-northeast in February and March, from the east 

from April through August, from the south in September, and from the northeast from October through 

December. The trade winds, particularly closer to the 

coast, are modified by land and sea breezes (Calvesbert 

1970). 

Mean monthly wind velocity ranged from 8 to 18 

km/hr at El Yunque and from 2 to 6 kmhr at Catalina 

(Briscoe 1966, Brown and others 1983). Peaks in wind 

velocity from 14 to 18 km/hr were recorded at El Yunque in December, January, April, and September. At 

Catalina, peaks from 4 to 6 kmhr were observed in 

April and from July through September. 

Diurnal variation in wind velocity showed interesting contrasts. On El Yunque, depending on the month, 

maximum velocities from 14 to 16 kmhr occurred from 

4 a.m. to 10 a.m., with minimum velocities between 11 

and 14 kmkr from 12 noon to 4 p.m. (Briscoe 1966, 

Brown and others 1983). At Catalina, maximum wind 

velocities from 4 to 6 km/hr occurred between 10 a.m. 

and 4 p.m. and minimum wind velocities from 2 to 3 

kmlhr at other hours. 

Cloud Cover and Solar Insolation. -Cloud cover 

increases with elevation in the Luquillo Mountains 

where the summits are frequently enveloped in clouds 

when the surrounding lowlands are clear. February 

and March are the months when the peaks are most 

likely to be cloud free. On Pico del Oeste, contrasting 

conditions were observed during 1 year of measurement. Two notable periods, one of 16 days in June 1966 

and the other of 15 days in January 1967, were recorded 

during which cIoud cover enveloped the peak continuously (Baynton 1968). During November 1966, however, 

a 3-week period averaging 15 hours per day of cloudfree weather was observed. 

Pico del Este was one of 10 North American sites 

where cloud water was considered an important input 

to local ecosystems (Weathers and others 1988). 

Between May 1984 and November 1985, cloud water 

and rainfall samples were collected on an event basis 

and chemically analyzed for concentrations of Ca2+, 

Mgz+, K+, Na+ , ammonium, sulfate, nitrate, and 

C1-. The pH was determined, and at a few sites, trace 

metals (Pb, Cu, and Zn) and organic compounds were 

sampled. 

The sea salt component, variable between events, 

contributed to a high mean ionic strength of samples 

from Pico del Este Weathers and others 1988). The 

variability was related to wind velocity and its influence on aerosol production. Comparably high nitrate 

concentrations were attributed to the oxidation of 

reduced nitrogen gases from the rain forest or from 

local pollution. Ammonium concentrations, also considered high, may have been associated with the rapid 

decomposition of organic matter from the surrounding 

rain forest. One cloud sample was visibly contaminated 

with a reddish material, possibly dust from the Sahara 

Desert. More recent work assessed the influence of sea 

salt aerosols on precipitation chemistry at El Verde, 

located in the LEF's tabonuco forest (McDowell and 

others 1990). 

Cloud cover affects incoming solar radiation. Mean 

annual solar radiation on El Yunque and Pico del Oeste 

averages 262 langleyslday, or 60 percent of that 

received at sea level on the northeastern coast of 

Puerto Rico (Baynton 1968, Briscoe 1966). Because the 
I TYPE A STORM TYPE B STORM I TYPE C STORM I 

1 1 I I I I I 1 I I I 

0 10 20 30 40 50 60 70 80 90 99 

YEAR 

Figure 8. -Hurricane record for Puerto Rico from 1700 to 1970 (Salivia 1972) updated to 1992: type A 

storm, vortex of hurricanepassed directly over the Island with hurricane force winds; type 

B storm, vortex of hurricane may or may not have passed over the Islnnd, but only part of 

the Island experienced hurricane force winds; type C storm, vortex passed at some distance 

from the Island, which experienced high winds (not hurricane force) and heavy rains; 

double I bar, two storms in the same year with intensity of second storm indicated by 

position of second I bar within the first; horizontal line from 1943 to 1992, years of 

measurement of tree growth in the Lquillo Forest; black circle, type A storms that passed 

directly over the Luquillo Forest. 

spectral composition of light changes little with cloudiness, light energy available for photosynthesis on the 

Luquillo Mountain summits is also reduced to 60 percent of that received in coastal areas (Baynton 1968). 

The mean monthly totals of incoming solar radiation 

for the coast and summits parallel each other. At the 

summits, mean monthly solar insolation peaks between 

320 and 380 langleyslday during March and April and 

is lowest at 175 langleyslday during December. Diurnal 

insolation patterns are also similar and peak near 1 

p.m. (Briscoe 1966, Brown and others 1983). 

Radiation fog may occur during the early morning 

hours in interior valleys throughout Puerto Rico, 

including those of the LEF. Often seen as blankets of 

cloud cover concentrated in low areas, these rapidly 

dissipate as the day progresses. 

Hurricanes. - September is the month of most frequent hurricane occurrence followed by August and 

July (Salivia 1972). About 80 storms have occurred in 

Puerto Rico since the early 1700's (fig. 8), many of 

which probably caused localized damage to vegetation 

in the Luquillo Mountains. Of these, 15 were A storms 

(vortex of the hurricane passed directly over the Island 

with hurricane-force winds), and 12 were B storms 

(vortex of the hurricane may or may not have passed 

over the Island, but only part of the Island experienced 

hurricane-force winds), for an average of one storm 

over at least part of the Island every 12 years (fig. 9). Of 

the A storms, four had trajectories directly over the 

Luquillo Mountains (fig. 8, 9). Based on existing data, 

hurricanes may be expected to pass directly over the 

LEF once every 62 years and to pass within 60 km once 

every 22 years (Scatena 1989). The LEF, then, could 

expect some damage from type A hurricanes at least 

once every 20 to 30 years. 

The effects of Hurricane San Felipe of 1928, as 

reported for the Luquillo district, included defoliation 

and breakage of branches, later followed by an abnormal production of seeds (Bates 1929). Hurricane San 

Cipriano of 1932 passed directly over the LEF and 

must have done considerable damage to the forest 

based on compositional and structural changes 

observed during recovery (Crow 1980; Weaver 1986a, 

1989). Hurricane Santa Clara of 1956 had very little 

effect on the LEF (Wadsworth and Englerth 1959). 

Hurricane Hugo of 1989, the first to have a major 

impact on the Luquillo Forest since San Cipriano of 

1932, passed over the northeastern tip of Puerto Rico. 

Sustained winds were in excess of 225 kmthr, and the 

total 3-day rainfall ranged up to 34 cm (Larsen 1989, 

Matos 1989). More than 200 landslides were detected 

within the mountains of northeastern Puerto Rico 

(Larsen 1989). Defoliation, stripping of branches, and 

tree fall were evident throughout the Baiio de Oro, 

which was well exposed to the storm. Hurricanes are of 

biological interest because of the long-term effects they 

have on forests and wildlife (Crow 1980; Walker and 

others 1991; Weaver 1986a, 1989). 
Figure 9.-Path of type A hurricanes with trajectories directly over Puerto RRico from 1700 to 1970. Solid lines are known 

trajectories and dashed lines are assumed trajectories based on descriptions (adapted from Saliuia 1972). Hurricane 

Hugo of 1989 passed just east of Fajardo. 

Hydrology 

Two major rivers, the Rio Mameyes and the Rio 

Fajardo, have their headwaters in the Baiio de Oro 

(figs. 2 and 4). The Rio Mameyes, made up of three 

tributaries with a combined river length of about 12 

km, flows north draining two-thirds of the Baiio de 

Oro. The Rio Fajardo, with one tributary, has a combined river length of 7 km. It flows north and then 

east, draining the remainder of the Baiio de Oro. 

A gauging station (I.D. No. 655) is situated at an 

84-m elevation on the Rio Mameyes at the border of the 

LEF (fig. 1). Records span periods from August 1967 to 

December 1973 and from June 1983 to the present 

(Curtis and others 1989). A 6-year record of annual 

discharge for the station ranged between 200 and 500 

cm, with a mean and standard error of 300 + 44 cm. 

The mean discharge of total dissolved solids associated 

with this flow was 3,324 t/yr and was linearly related to 

river discharge (Brown and others 1983). The mean 

rates of monthly discharge are the lowest and with the 

least variability between February and April (fig. 10). 

They peak in May and October, with the greatest variability in October. Water quality parameters are shown 

in table 2. 

A second gauging station, situated at a 42-m elevation on the Rio Fajardo, has experienced flood damage 

on several occasions. Low and peak flow discharges 

were sometimes recorded in 1960-61; water discharge, 

however, has been recorded from March 1961 to the 

present (Curtis and others 1989). The average discharge over the 28-year period is 1.98 m3Is. The maximum discharge for the same period occurred during 

Hurricane Hugo, September 18, 1989, when 665 m3/s 

were recorded. Minimum discharge, 0.86 m3/s, 

occurred on May 3,1984. Records are rated as fair with 

low flow affected by diversions for water supply. 

Flooding is most likely to occur between May and 

November, the time of maximum rainfall expectancy. 

The combination of heavy rainfalls and steep slopes 

sometimes concentrates runoff into flows that exceed 

stream channels for short periods. Flooding is most 

likely to be associated with major rain-producing 

events such as tropical storms, cold fronts, or hurricanes (Calvesbert 1970). Flooding in the upper headwaters of the Rio Mameyes and Rio Fajardo, however, is 

localized and of short duration because of the steep 

topography. 

FLORA 

Major Forest 'Qpes 

Three sets of nomenclature are commonly used to 

refer to the forests of the LEF, and each serves a 

particular audience: local names in Puerto Rico 

(Wadsworth 1951), Beard's (1944,1949) terminology in 

the Caribbean, particularly the Lesser Antilles, and 

Holdridge's (1967) life zone system commonly used in 

Central and South America and the Greater Antilles. 

The Baiio de Oro is divided into two life zones (Ewe1 

and Whitmore 1973): the subtropical rain forest and 

the subtropical lower montane rain forest (fig. 11). In 

Puerto Rico, these life zones are confined to the 

Luquillo Mountains. The subtropical rain forest is 

located at intermediate elevations to the windward 
Table 2.-Mean water qualityparameters for the Rio Mameyes for the 

period 1969-74 * 

Parameter 

Values* 

(mean -t SE) 

Temperature ("C) 22.9 (0.2) 

Specific conductance (p)* 85.3 (17.1) 

PH 7.2 (0.10) 

Alkalinity fmg1L)S 32.8 (2.7) 

Ca (mglL) 10.5 (0.4) 

Mg fmg/L) 2.5 (0.03) 

Na (mglL) 6.7 (0.2) 

K ((mglL) 0.60 (0.04) 

cl (mg/L) 8.4 (0.2) 

SO, (mglL) 4.0 (0.4) 

NO8 (mg/L) 0.20 (0.05) 

Dissolved PO, (mglL) 0.30 (0.3) 

*Brown and others 1983, based on U.S. Geological Survey records. 

tSE = standard errors (in parentheses); number of observations 

= 34; elwation = 84 m. 

tPs = microsiemens per centimeter at 25 "C (measure of water's 

capacity to conduct a current). 

PmgiL = milligrams per liter. 

where it occupies 1,420 ha, or 13 percent of the LEF. 

Twenty-seven percent of the 1,420-ha total, or 385 ha, 

is in the Baiio de Oro. The second life zone is concentrated on windward slopes and summits and occupies 

1,180 ha, or about 10 percent of the LEF. Thirty percent of the 1,180-ha total, or 360 ha, is in the Baiio de 

Oro. 

Four of Beard's forest types are recognized in the 

Bafio de Oro: lower montane rain forest, montane rain 

forest, palm brake, and dwarf forest. Locally, these 

forests are known as tabonuco, colorado, palm, and 

dwarf forests, respectively. For convenience, local 

names will be used hereafter in the text. 

General descriptive information for the four forest 

types is provided in table 3. The tabonuco forest, 

extending to about a 600-m elevation in the LEF, 

occupies 56 percent of the Baiio de Oro (fig. 11). It is 

dominated by Dacryodes excelsa, Sloanea berteriana, 

and Manilkara bidentata in the overstory. The colorado 

forest, which lies between 600 and 900 m in elevation, 

is dominated by Cyrilla racemiflora, Micropholis 

chrysophylloides, and M. garciniaefolia in the overstory. The dwarf forest, a gnarled, epiphyte-laden, and 

dense forest type, occupies the slopes and summits 

above 900 m in elevation. Tabebuia rigida, Ocotea 

spaihulata, and Eugenia borinquensis are the most 

common species. Finally, the palm forest, dominated by 

Prestoea montana, the sierra palm, is concentrated on 

steep slopes and in ravines above a 500-m elevation. 

Other Vegetation Mes 

There is an alpine meadow in the dwarf forest of the 

Baiio de Oro (fig. 2). Its soil is characterized by a 

hardpan 60 to 70 cm below the surface (Odum 1970). 

The origin of the meadow is uncertain but may be 

related to site disturbance such as a landslide during 

heavy rains or a major hurricane (Guariguata 1990, 

Larsen 19891, followed by soil changes Weaver 1990). 

Once formed, the hardpan prevents percolation and 

may retard the penetration of tree roots. 

A Pterocarpus stand extends behind the eastern 

bank of the Rio Mameyes at the confluence of the Rio 

de la Mina (fig. 2). The stand, occupying c 1 ha, borders 

the Bafio de Oro. Its location at a 245-m elwation in the 

LEF is notable because most Ptemcarpus forests in the 

Caribbean are situated in intermittently flooded 

coastal lowlands. 

The stand was studied in detail as part of a thesis 

program (Alvarez-Lopez 1990, Alvarez Ruiz 1982). Several of the larger trees range from 40 to 80 cm in 

diameter, and the tallest is 32 m. Seedling regeneration 

is abundant. Detailed structural information is available for the stand, including species importance values, 

a species-area curve, a complexity index, a stand profile, phenological observations, root biomass, soil profile, litter standing crop, and soil organic matter 

storage. 

'bee Species Distribution 

The LEF has 225 species of native trees in 144 genera and 59 plant families. The closest botanical 

affinities are with Hispaniola and Cuba, but South 

America appears to have been the source of the first 

immigrants (Little 1970). Forty-one percent of the 

LEF's tree species are also found on the mainlands of 

South America, Central America, Mexico, and Florida. 

Moreover, 28 percent are found in the West Indies but 

not on the continents, and 31 percent are endemic to 

Puerto Rico (Little and Woodbury 1976). 

Of the 88 species classified as endemic or rare in the 

LEF, 23 species are endemic only to the LEF, another 

45 species are endemic to Puerto Rico and found in the 

LEF, and 20 species are classified as rare in Puerto 

Rico but also native to areas outside of Puerto Rico. 

Pico del Oeste Flora 

Between 1966 and 1977, staff members of the Arnold 

Arboretum and collaborators published the results of 

17 studies conducted in the dwarf forest of Pico del 

Oeste. An introduction, objectives, and general description of the dwarf forest program were outlined by 

Howard (1968, 1970b). The work encompassed studies 

of species composition (vascular plants, mosses, leafy 

Hepaticae, and algae), which are reported below. 

Vascular Plants. -A survey of the vegetation for 

the entire Pico del Oeste summit area disclosed 97 

species of vascular plants, 85 of which were considered 

to be the principal species (table 4). Of the latter, 31 

were species of ferns, 14 were Monocotyledoneae, and 
140 - 

RIO MAMEYES 

120 - ELEVATION = 83.8 m 

- 100 - -,- 

5 - T 

L 

2 80 

- 

fk 

60 - 5 - 

rt! 

B 40 - 

- I, 

20 - -L - & i 

MONTH 

Figure lo. - Mean monthly discharge fmm th Rio Mamqes (in black circles) and range of monthly 

discharges (bars) (Brown and others 1983). 

a DWARF FOREST 50 ho 16.7 

Figure 11.- Life zone and forest type map of the Baa di Om Naiuml Area (Institute of ~ical Forestry files). 
Table 3. -Forests of the Bario de Om Natural Area 

Forest 

type Area 

Tree 

Tree species* height Elevation 

Hectares Percent 

Tabonuco 416 56 

Colorado 136 18 

Palm 143 19 

Dwarf 50 7 

- - Total 745 100 

Total No.lha ----------------- Meters ------------------ 

153 50 > 30 ~600 

101 35-40 15 600-900 

26 < 20 15 >500 (steep slopes 

and arroyos) 

43 < 15 5-7 > 900 (exposed slopes 

- and summits) 

225 -- - 

*Little and Woodbury 1976. Species data refer to entire LEF and are not additive because of overlap 

among forest types. The number of species in the natural area is unknown. 

Table 4. -Vascular plant species list for Pico del Oeste in the Bario de Om Natural 

Area * 

Nomenclature 

Lycopodiophyta 

Lycopdiaceae 

Lycopodium cernunm L. 

L. taxifolium Sw. 

Selaginellaceae 

Selaginella krugii Hieron 

S. substipitata Spring 

Polypodiophyta 

Cyatheaceae 

Cyathea borinquena (Maxon) Domin 

C. pubescens Mett. ex Kuhn 

Lophosoria quadripinnata (Gmel.) C. Chr. 

Pol ypodiaceae 

Blechnum divergens (Kunze) Mett 

B. lineatum (Sw.) Hieron 

B. underwoodianum (Broadh.) C. Chr. 

Cochlidium minus (Jenm.) Maxon 

C. seminudum Willd.) Maxon 

Diplazium centripetale (Baker) Maxon 

D. grandifolium Sw. 

D. 1 'herminieri Hieron 

D. striatum (L.) Presl 

Elaphoglossum firmum (Mett.) Urban 

G. hessii (Maxon) Alain 

G. serrulata (Sw.) Sw. 

G. taenifolia (Jenm.) Proctor 

Lindsaea stricta (Sw.) Dryand 

Oleandra articulata (Sw.) Presl 

Peltapteris peltata (Sw.) Morton 

Pdybotrya cervina (L.) Kaulf 

Polypodium chmdes Spreng 

I? loriceum L. 

Thelypteris decussata (L.) Proctor 

Hymenophyllaceae 

Hymenophyllum linceare Sw. 

H. macrothecum Fee 

Zkichomanes crispurn L. 

T. rigzdum Sw. 
Table 4. -Vascular plant species list for Pico del Oeste in the Bario de 0x1 Natural 

Area*- Continued 

Nomenclature 

Magnoliophyta-Liliatae 

Gramineae 

Andropogon bicornis L. 

Arthrostylidium sarmentosum Pilger 

Ichnanthus pallens (Sw.) Munro 

Isachne angustifolia Nash 

Cyperaceae 

Caw polystachya Sw. ex Wahlenb 

Eleocharis yunquesis Britton 

Fimbristylis dichtoma (L.) Vahl 

Scleria secans (L.) Urban 

Palmae 

Prestoea mntana (R. Grah.) Nichols 

Araceae 

Anthurium dominicense Schott 

Bromeliaceae 

Guzmania berteroniana (R. & S.) Mez 

Vriesia sintenisii (Baker) Smith & Pittend 

Dioscoreaceae 

Rajania cordata L. 

Zingiberaceae 

Renealmia antillarum (R. & S.) Gagnep 

Orchidaceae 

Brachionidium parvum Cogn 

Dilomilis mntana (Sw.) Summerhayes 

Epidendrum nocturnum Jacq 

E. pallidiflorum Hook 

Piperaceae 

Pepemia emarginella (Sw.) DC . i? hrnandiifoliu Wahl) A. Dietr 

Chloranthaceae 

Hedyosmum arborescens SW. 

Moraceae 

Cecropia peltata L. 

Urticacea 

Pilea krugii Urban 

R obtusota Liebm 

R yunquensis (Urb.) Britt. & Wds. 

Lauraceae 

Ocotea spathulata Mez 

Magnoliaceae 

Magnolia splendens Urban 

Cunoniaceae 

Weinrnannia pinnata L. 
Table 4. -Vascular plant species list for Pico del Oeste in the Baiin de Om Natural 

Area * - Continued -- 

Nomenclature 

Meliaceae 

Dichilia pallida Sw. 

Aquifoliaceae 

Zlex sintenisii (Urb.) Britton 

Celastraceae 

'Ibrralbasia cuneifolia (C. Wr. ex Griseb.) 

Krug & Urban ex Segui 

Ochnaceae 

Sauvagesia erecta L. 

Marcgraviaceae 

Marcgrauia sintenisii Urban 

Theaceae 

Cleyera albopunctata (Griseb.) Krug & Urban 

Guttiferae 

Clusia grisebachiana (Planchon & Triana) Alain 

C. gundlachii Stahl 

Begoniaceae 

Begonia decandra Pav. ex A. DC. 

T hymelaeaceae 

Daphnopsis philippiana Krug & Urban 

MYCalyptranthes krugii Kiaersk. 

Eugenia borinquensis Britton 

Calycogoniurn squarnulosurn Cogn 

Mecranium arnygdalinum (Desr.) C. Wright ex Sauv 

Miconia fowoloto Cogn 

M. pachyphylla Cogn 

M. pycnoneum Urban 

M. sintenisii Cogn 

Ericaceae 

Gonocalyx portoricensis (Urb.) A. C. Sm. 

Hornemannia mcemosa Vahl. 

Myrsinaceae 

Ardisia luquillensis (Britton) Alain 

Gmmmadenia sintenisii (Urb.) Mez 

Wallenia yunqmnsis (Urb.) Mez 

Sapotaceae 

Micropholis garciniaefolia Pierre. 

Symplocaceae 

Symplocos rnicrantha Krug & Urban 

Oleaceae 

Haenianthus salicifolius Griseb. var. obovatus (Krug & Urb.) Knob1 

Convolvulacear! 

Ipomoea repanda Jacq. 
Table 4.- Vascular plant species list for Pico del Oesle in the Barw de Om Natuml 

Area* - Continued 

Nomenclature 

Boraginaceae 

Cordia borinquesis Urban 

Bignoniaceae 

'Ihbebuia rigida Urban 

Alloplectus ambiguus Urban 

C;esneria sintenisii Urban 

Acanthaceae 

Justicia martinsoniana Howard 

Rubiaceae 

Hillia parasitica Jacq. 

Psyclwtria berteriana DC. 

P. guadalupensis (DC.) Howard 

Roncleletia portoricensis Krug & Urban 

Campanulaceae 

Lobelia portoricensis Wke) Urban 

Compositae 

Clibadium emsum (Sw.) DC. 

Mikania pachyphylla Urban 

*Source: Howard 1968. 

40 were Dicotyledoneae (Howard 1968). Of the species 

sampled on Pico del Oeste, 32 percent were endemic to 

Puerto Rico, 40 percent were restricted to the Greater 

and Lesser Antilles, and 28 percent were found in the 

Antilles and in continental areas (Howard 1968). 

Mosses. - Twenty-three species of mosses were identified (table 5) (Russell and Miller 1977). Most species 

grow at the base of trees with about half occurring at 

other levels. Species growing on the forest floor have a 

lower resistance to desiccation than those in treetops, 

whereas the latter are more tolerant of higher light 

intensities. 

Leafy Hepatieae. -Although the dwarf forest is 

sometimes called "mossy," leafy Hepaticae comprise 

most of the bryophyte flora. Fifteen families, 34 genera, and 62 species were identified on Pico del Oeste 

(table 6) (Fulford and others 1970, 1971). Considerable 

differences in species composition were observed for 

hepatic flora on different peaks within the LEF. 

Algae. -Some 123 species of epiphytic algae were 

identified with their vascular hosts on Pico del Oeste 

(table 7) (Foerster 1971). Sampling disclosed that they 

were not uniformly distributed but were segregated 

into various intergrading synusia. A general shift from 

Bacillariophyta- to Cyanophyta- to Chlorophytadominated synusia was observed, a phenomenon apparently related to an increase in height and changes in 

host material. Moreover, a vertical shift of algae, or 

season4 response to environmental utilization, is evident during the year, probably as a reaction to greater 

cloud cover during the wet season than in the dry 

season. 

Other studies of the flora on Pico del Oeste included 

the following topics: stem growth, form, and leaf structure (Howard 1969); chromosome numbers and flowering cycles of dwarf forest species (Nevling 1969, 1971); 

transpiration rates and leaf temperatures (Gates 1969); 

soil and roots, including aerial roots (Gill 1969, Lyford 

1969); phytochemical screening and chemistry of colored leaves (Persinos and others 1970, Wagner and 

others 1969); and the occurrence and growth of Marcgravia (Howard 1970a) and Gonocalyx (Nevling 1970). 

Other Dwarf Forest Studies. -The dwarf forest 

on Pico del Este, at virtually the same elevation and <2 

km distant from Pico del Oeste, has also been studied 

(Weaver 1972a, 1972b). Twenty-eight species of endemic 

plants and 28 species of vertebrate fauna were identified. The arborescent vegetation contained only a few 

tree species characterized as small in stature and high 

in stem density and basal area. 
Table 5.-Moss species list for Pico del Oeste in the Barin de Om Natural Area* 

Nomenclature 

Acroporium acestrostegium 

A. pungens 

Callicostella depressa 

Campylopus cygneus 

Hemiragis aurea 

Hookeriopsis acicularis 

H. obsoletinervis 

Hypnelln filiformis 

Zsodrepanium lentulum 

Lepyrodontopsis trichophylla 

Leucobryum crispum 

L. rnartianum 

Leucoloma serrulatum 

L. shwaneckeanum 

Leucophanes calymperatum 

Macromitrium perichaetiale 

M. schwaneckeanum 

M. scoparium 

Pilotrichurn evanescens 

Syrrhopodon prolifer 

Thuidium urceolatum 

Dichosteleum sentosum 

Vesicularia sp. 

*Source: Russell and Miller 1977. 

Cyrilla racimiflora regeneration on an overturned tree after Hurricane Hugo within the Bafio de Om Natural Area. 
Table 6.- Leafy Hepaticae species list for Pico dd Oeste in the Barw de Om Natural 

Area* 

Nomenclature 

Trichocoleaceae 

Dichocolea breuifissa Steph. 

T. elliottii Steph. 

T. filicaulis Steph. 

T. flaccida (Spr.) Jack & Steph. 

Isotachidaceae 

Neesioscyphus bicuspidatus (Steph.) Grolle 

Herbertaceae 

Herberta divergens (Steph.) Herz. 

H. elliottii Spr. 

H. juniperoidea (Sw.) Grolle 

H. pensilis (T. Tayl.) Spr. 

Lepidoziaceae 

Bazzania bidens (Nees) Trevis. 

B. breuteliana (Lindenb. & Gott.) Trevis. 

B. cubensis (Gott.) Pagh 

B. eggersiana (Steph.) Pa@ 

B. gracilis (Hampe & Gott.) Steph. 

B. hookeri (Lindenb.) Trevis. 

B. longa (Nees) Trevis. 

B. longistipula (Lindenb.) Trevis 

B. roraimensis (Steph.) Fulf. 

B. schwaneckiana (Hampe & Gott) Trevis. 

B. stolonifem (Sw.) Trevis. 

Lepidozia patens Lindenb. 

Microlepidozia capillaris (Sw.) Fulf. 

Micropterygium carinatum (Grev.) Reim. 

M. aa2atum Steph. 

Telaranea sejuncta (Angstr.) S. Arnell 

Calypogeiaceae 

Calypogeia caespitosa (Spr.) Steph. 

C. cellulosa (Spreng.) Steph. 

C. crenulata Bischl. 

C. cyclostipa (Spr.) Steph. 

C. elliottii Steph. 

C. laxa Gott. & Lindenb. 

C. lophocoleoides Steph. 

C. peruviana Nees & Mont. 

Cephaloziaceae 

Cephalozia caribbeania Fulf. 

C. cmsifolia (Lindenb. & Gott.) FuK 

C. subfor/kda Herz. 

Nowellia caribbeania Fulf. 

N. dominicensis Steph. 

Odontoschismaceae 

Alobiellopsis dominicensis (Spr.) W. 

Odontoschisma denwZntum (Nees) Durn. 

0. longiflorum (T. ?Byl.) Steph. 

0. prostratum (Sw.) Trevis. 

Re@caulaceae 

Arachniopsis coactilis Spr. 

Zoopsidaceae 

Zoopsis antillana Steph. 

Alobiellaceae 

Alobiella husmti (Gott.) Schiffn. 

Paracromastigaceae 

Leucosarmntum portoricense Fulf. 
Table 6.-Leafy Hepaticae species list for Pico &l Oeste in the Barb de Om Natural 

Area * - Continued 

Nomenclature 

Lophocoleaceae 

Hetemscyphus elliottii (Steph.) Pagh 

Leptoscyphus gibbosus (T. Tayl.) Mitt. 

Lophocolea guudeloupensis Steph. 

L. martiana Nees 

Lophcziaceae 

Syzygiella perfoliata (Sw.) Spr. 

S. rubricalis (Nees) Steph. 

Jungermanniaceae 

Jungermannia dominicensis Spr. 

Adelanthaceae 

Adelanthus decipiens (Hook.) Mitt. 

Plagiochillaceae 

PlagLochila abrupta Lehm. & Lindenb. 

I? adiantoides (Sw.) Dum. 

l? amoena Steph. 

l? arcuota Lindenb. 

l? bicornis Hampe & Gott. 

l? bidens Gott. 

I! b~utdiana Lindenb. 

l? bursata (Desv.) Lindenb. 

l? chinantlam Gott. 

l? confundens Lindenb. & Gott. 

l? distinctifolia Lindenb. 

I? divaricata Lindenb. 

I? dominicensis T. nyl. 

l? jarnaicensis Lindenb. & Hampe 

l? rutilans Lindenb. 

l? simpler (Sw.) Dum. 

l? subbidentata T. nyl. 

l? tamariscina Steph. 

l? ? tenuis Lindenb. scraps 

Scapaniaceae 

Scapania portoricensis Hampe & Gott. 

Radkae 

Radula fendleri Gott. 

R. inflexa Gott. ex Steph. 

R. kegdii Gott. ex Steph. 

R. longifolia Steph. 

R. saccatiloba Steph. spp. 

F'rullaniaceae 

Frullania atrota (Sw.) Dum. 

l? bmsiliensis Raddi 

F. exilis T. %yl. 

l? kunzei Lehm. & Lindenb. 

I? subtilissima (Nees & Mont) Lindenb. 

Lejeuneaceae 

Arwplolejeunea conferta (Meissn.) Evans 

Archikjeunea viridissimu (Lindenb.) Steph. 

Ceratolejeunea brevinervis (Spr.) Evans 

C. cornuta (Lindenb.) Steph. 

C. cubensis (Mont.) Schiffn. 

C. Frgelliformis (Steph.) Fulf. 

C. maritimu (Spr.) Steph. 

C. patentissima (Hampe & Gott.) Evans 

C. rubiginosa Steph. 
Table 6.- Leafy Hepaticae species list for Pico del Oeste in the Bario de Om Natural 

Area * - Continued 

Nomenclature 

-- - 

C. spinosa (Gott.) Steph. 

C. valida Evans scraps 

Cheilolejeunea a'ecidua Spr. 

C. polyantha Evans 

Colura clauigera (Gott. ex Schiffn.) Jovet-kt 

C. rhynchophora Jovet-Ast 

Crossotolejeunea bermudiana Evans 

C. boryana (Mont.) Steph. 

Cyclokjeunea wcedens (Gott.) Evans 

C. angulistipa (Steph.) Evans 

C. chitonia (T. Tayl.) Evans 

C. convexistipa (Lehm. & Lindenb.) Evans 

Cyrtokjeunea holostipa (Spr.) Evans 

Cystolejeunea lineata (Lehm. & Lindenb.) Evans 

Diplasiolejeunea brachyclada Evans 

D. pellucida (Meissn.) Schiffn. 

D. unidentata (Lehm & Lindenb.) Schiffn. 

Drepanolejeunea anoplantha (Spr.) Steph. 

D. crucianella (T. Thy].) Evans 

D. evansii Bischl. 

D. fragilis Bischl. 

D. inchoata (Meissn.) Schiffn. 

D. lichenicola (Spr.) Steph. scraps 

Euosmolejeunea clausa (Nees & Mont.) Evans 

E. rigidula (Nees & Mont.) Steph. 

E. trifaria (Nees) Schiffn. 

Harpakjeunea heterndonfa Evans 

H. subacuta Evans 

H. uncinata Steph. 

Hygrokjeunea sp. 

Lejeunea flava (Sw.) Nees 

Leptolejeunea elliptica (Lehm. & Lindenb.) Schiffn. 

L. hamulata Schifln. 

Leucolejeunea xanthocarpa (Lehm. & Lindenb.) Evans 

Lopholejeunea howei Evans 

L. miilkrianu (Gott.) Schiffn. 

L. sagraeana (Mont.) Schiffn. 

Macrolejeunea subsimpla (Nees & Mont.) Schiffn. 

Marchesinia brachiata Schiffn. 

Microlejeunea acutifolia Steph. 

M. bullata (T. Wl.) Steph. 

M. laetevirens (Nees & Mont.) Evans 

M. monoica Bischl. 

Neurokjeunea breutelii (Gott.) Evans 

Odontokjeunea lunulata (Web. ) Schiffn. 

Omphalanthus filiformis (Sw.) Nees 

Prionokjeunea aemula (Gott.) Evans 

P. aequitala Evans 

I? ouurriculata Evans 

R helkri Evana 

I? innovata Evans scraps 

Ptychocoleus polycapus (Nees) !Crevis. 

Pycnolejeunea schwaneckii (Steph.) Schif'fn. 

Rectolejeunea bertemnu (Gott.) Evans 

R. phyllobola (Nees & Mont.) Evans 

Stictolejeunea squamata (Vir111d.) Steph. 

Strepsilejeunea iruroluta Steph. 

Symbiezidium barbiflorum (Lindenb. & Gott.) Evans 

S. laceratum Evans. 

S. transversak (Sw.) 1Crevis. 

kilejeunea obtusangulata (Spr.) Evans. 

T. sulphurea (Lehm. & Lindenb.) Steph. 

Thehylejeunea inflax Steph. 

*Sources: F'ulford and others 1970, 1971. 
Table 7. -Algae species list for Pico del Oeste in the Bark de Oro Natural Area* 

Nomenclature 

Cyanophyta 

Chroococales 

Aphamcapsa biformis A. Br. 

A. grevillei (Hass.) Rabenh. 

A. roeseana DeBary 

Aphanothece clathrata W. & G. West 

A. microscopica Niig. 

A. sazicola Niig. 

Chroococcus dispersus (Keissler) Lemm. 

C. dispersus var. minor G. M. Sm. 

C. giganteus W. West 

C. limneticus Lemm. 

C. minor (Kiitz.) Niig. 

C. minutus (Kiitz.) Niig. 

6. pallidus Niig. 

C. turgidus (Kutz.) Niig. 

C. varius A. Br. 

Dactylococcopsis fascicularis Lemm. 

D. smithii R. & I?. Chodat 

Gloeocapsa ~ruginosa (Carm.) Kiitz. 

G. polydermatica Kiitz. 

Gloeothece linearis var. composita G. M. Sm. 

G. paka (Kutz.) NZLg. 

G. paka (Kutz.) Rabenh. 

Merismpedia aeruginea B&b. ex Kutz. 

M. elagans A. Br. ex Kutz. 

M. glauca (Ehrenb.) Niig. 

M. punctda Meyen 

M. tenuissima Lemm. 

Microcystis aeruginosa Kiitz. 

M. elabens (Breb) Kutz. 

M. incerta Lemm. 

M. ramsa Braradw. 

M. orissica (?) W. West. 

Pelogloea bacillifera Lauterborn 

Rhabdoderma sp. 

Synechococcus aeruginosus Niig. 

Chamaesiphonales 

Chamaesiphon confervicola A. Br. 

C. rostaffinskii Hansg. 

Nostocales 

Anabaenu ammala Fritsch 

A. circinalis Rabenh. 

A. laze (Rabenh.) A. Br. 

Anabaena sp. 

A. ow Fritsch 

A. oscillarioides Bory ex Born. & Flah. 

Aulosira fritschii Bharadw. 

A. prolifica (?) Bharadw. 

A. prolifica Bharadw. 

Calothrir epiphytica W. & G. West 

C. weberi Schmidle 

Coelosphuerium dubium Gmn. 

Cylindrospermum cdenatum (?) Ralfs 

Gloeotrichia echinnulata (J. E. Sm.) Richter 

G. longiarticulnta G. S. West 

Lyngbya limnetica Lemm. 

Microchuete uberrima Carter 

Nostoc muscorum C. Ag. 

Oscillatoria agardhii Gom. 

0. annae van Goor 

0. foreaui Wmy 
Table 7.-Algae species list for Pico del Oeste in the Bario de Om Natural Area* 

Nomenclature 

0. geitleriana Elenkin 

0. limnetica Lemm. sp. 

Oscillatoria sp. 

0. subbreuis Schmidle 

Phormidium tenue (Menegh.) Gom. 

Pseuclanabaena catenata Lauterb. 

F! constricts (Szitfer) Lauterb. 

Schizothrix ericetorum Lemrn. 

Scytonema amplum W. & G. West 

S. burmanicum Skuja 

S. hofmannii C. Ag. ex Born. & Flah. 

S. javanicum (?) (Kiitz.) Born 

S. schmidtii (?I Gom. 

S. stuposum (Kutz.) Born. ex Born. & Flah 

S. tolypothricoides Kiitz. ex Born. & Flah. 

Scytonematopsis kashyapii (Bharadw.) Geitler 

Spirulina subtilissima Kiitz. 

7blypothri.x distorta Kiitz. ex Born. & Flah. 

Pleurocapsales 

Myzosarcina spectabilis Geitler 

Xenococcus kerneri Hansg. 

Stigonematales 

Camptylonerna indicum Schmidle 

Hapalosiphon delicatulus W. & G. West 

H. fontinalis (Ag.) Born. 

H. hibernicus W. & G. West 

H. inteolus W. & G. West 

H. intricatus W. & G. West 

H. luteolus W. & G. West 

H. stuhlmannii Hieron. 

H. welwitschii W. & G. West 

Nostochopsis lobatus Wood em. Geitler 

Plectonema indica Dixit 

Stigonema aerugineum Tilden 

S. dendroideum FMmy 

Stigonema kormides (Kiitz.) Born. & Flah. 

S. informe Kiitz. 

S. mesentericum Geitler 

S. minutum (C. Ag.) Hass. 

S. panniforme Harv. ex Born. & Flah. 

S. turfaceum (Berk.) Cooke ex Born. & Flah. 

Chlorophyta 

Chaetophorales 

Cephaleums virescens Kunze 

Protococcus uiridis C. Ag. 

Stigeoclonium polymrphum (?) (Franke) Heering 

Dentepohlia area var. tenuior Briihl & Biswas 

Z! aurea (L.) Martius 

T. iolithus (L.) Wallroth 

T. torulosa De Wildeman 

Z! umbrina (Kiitz.) Born. 

Chlorococcdes 

Ankistodesmus falcatus (Corda) Ralfs 

Characiurn stipitatum (Bachm.) Wde 

C. obtusum (?) Braun 

Chlorella ellipsoidea Gern. 

C. vulgaris Beyerinck 

Chlomcoccum humicola (Nag.) Rabenh. 

Crucigenia quadrata Morren 

Ooeystis borgei Snow 
Table 7.-Algae species list for Pico del Oeste in the Baa de Oro Natural Area* 

Nomenclature 

0. pyriformis Prescott 

0. submarina Lagerheim 

Pediastrum muticum var. crenulatum Prescott 

I! muticum Kiitz. 

Quadrigula chodatii (Tanner-F'iillemann) G. M. Sm 

Q. lacustris (Chod.) G.M. Sm 

Scenedesmus arcuatus var. platydisca G.M.Sm. 

Tetraedmn tumidulum (Reinsch) Hansg. 

%chiscia qranulata (Reinsch) Hansg. 

Cylindrocapsales 

Cylindrocapsa conferta W. West 

C. geminella Wolle 

Oedogoniales 

Oedogonium sp. 

Pithophora oedogonia (Mont. ) Wittr. 

Sphaeropleales 

Sphaemplea annulina (Roth) C. Ag. 

Tetrasporales 

Gloecystis major Gerneck 

G. wsiculosa Nlig. 

Sphaerucystis schmeteri (?) Chooat 

Tribonematales 

Dibonema utriculosum (Kiitz.) Hazen 

Ulotrichales 

Geminella interrupta 'Jhrpin 

Stichococcus subtilis (Kiitz.) Klercker 

Ulothrix aequalis Kiitz. 

U. variabilis Kiitz 

Zygnematales 

Cosmarium dentatum WoUe 

Cosmarium sp. 

Cylindrucystis brebissonii var. minor W. & G. West 

Euastrum q. 

Hyalotheca undulata Nordst. 

Micrasterias denticulata (?) Breb. 

M. caimani Transeau 

M. floridam Transeau 

Mougeotia globulispom Jao 

Netrium digitus (Ehmb.) Itzigos. & Rothe 

Temnogarnetum transeaui hscott 

Zygnemopsis desmidioides (W. & G. west) Transeau 

Zygogonium ericetorum Kiitz. 

Heterococcales 

Pemniella planctonica G. M. Sm. 

Pleumgaster lunaris Pascher 

Tetragoniella gigas Pascher 

Rhyzochrysidales 

Chrysidiastrum catenatum Lauterb. 

Lagynion reductum Prescott 
Table 7.-Algae species list for Pico del Oeste in the Bario & On, Natural Area* 

Nomenclature 

Bacillariophyta 

Centrales 

Biddulphia alternuns (bail.) Van Heurek 

B. fwus (Ehrenb.) Van Heurck 

Campylodiscus echeneis (?) Ehrenb. 

Coccimdiscus lacustris (?) Grun. 

Cyclotella bodanica (?) Eulenst. 

C. glomerata Bachm. 

Melosira crenulata (Ehrenb.) Kutz. 

M. granulata (Ehrenb.) Ralfs 

M. varians C. Ag. 

Piceratiurn semicirculare Brightw. 

T. undulatum Ehrenb. 

Pennales 

Achanthes hwkiana Grun. 

A. microcephala (Kutz) Grun. 

Amphora ovalis Kiitz. 

Anomoeoneis costata (?) (Ktitz.1 Hust. 

Cymbella uentricosa Kutz. 

Dentivuh sp. 

Diatoma hiernale (Roth) Heib. 

D. hiemak var. mesodon (Ehrenb.) Grun. 

D. tenue var. ebngatum Lyngb. 

Diatoma vulgare Bow 

Diatomella balfouriana Gm. 

Diploneis oculata (Breab.) C1. 

Eunotia exigua (?) (Br6b) Rabenh. 

E. fallux Cleve-Euler 

E. naegelii Mig. 

E. pectinalis f. elongata van Huerck 

E. pectinalis var. minor (Kiitz.) Rabenh. 

E. perpusilla (?) Grun. 

E. praerupta Ehrenb. 

E. soleimlii (Kutz.) Rabenh. 

Eunotia sp. 

E. tenel& (Gmm.) Hust. 

Fmgilaria breuistriata Grun. 

F. lapponica Grun. 

Frustulia rhomboides var. capitata (Mayer) Patr. 

F. rhomboides var. samnica (Rabenh.) De'Ibni 

l? rhomboides var. viridu2a (Bdb.) C1. 

Hantzschia amphimys (Ehrenb.) Grun. 

Zsthmia eneruis Ehrenb 

Navicula carnidensis (?) Hust. 

N. cineta (Grun.) C1. 

N. contenta Grun. 

N. crucicula (?) (W. Smith) Donk 

N. cryptocephala t?) Kiitz. 

Navicula spp. (3 separate species) 

N. tenelloides Hust. 

Nitzschia biacrula (?) Hohn & Hellerman 

N. dissipata (Kutz.) Grum. 

N. ltantzschiana Rabenh. 

N. igmmta Krasske 

N. parvula Lewis 

N. tryblwnella Hantzsch. 

Pinnularia sudentica Hilse 

l? viridis var. minor Cleve 

Rhopalodia gibberula (Ehrenb.) Mueller 

R. uentricosa (Kiitz) Mueller 

Stwroneis ignorata (?) Hust. 

Surirella ovata Kutz. 

lFopidoneis sp. 
Table 7. -Algae species list for Pico del Oeste in the Bario de Om Natural Area* 

Nomenclature 

Pyrmphyta 

Dinococcales 

Cystodinum cornifaz (Schilling) Klebs 

Euglenophyta 

Euglenales 

Eugleruz elastica (?) Prescott 

E. polymorpha Dangeard 

Glenodinium kulczynskii (?) (Wolosz.) Schiller 

Trachelomonas charkowiensis (?) Swirenko 

*Source: Faerster 1971 

Dee fall gap with regeneration of Cecropia peltata in the Balio de On, Natural Area. 
Transpiration rates of dwarf forest trees were observed 

to be relatively low when compared to other environments 

(Medina and others 1981, Weaver and others 1973). Different rates were detected between primary and secondary species and between sun and shade exposures 

(Weaver 1975). Moreover, rates were negatively correlated 

with the amount of cloud cover on the peaks. 

Tree diameter increment averaged 0.03 cmlyr, and 

aboveground biomass accumulation was estimated at 

0.45 t/ha/yr (Weaver and others 1986). Litterfall averaged 3.1 t/ha/yr, 79 percent of which was leaf litter, 9 

percent wood litter, and 12 percent miscellaneous material. Leaf herbivory was estimated at 5.5 percent, or 

0.13 t/ha/yr (Benedict 1976). These data yield an estimate of aboveground primary productivity of nearly 

3.7 thalyr (Weaver and others 1986). 

Dwarf forest succession after disturbance was 

observed for nearly 20 years near Pico del Este. Recovery after 6 years was characterized mainly by woody 

sprouts, ferns, and grasses, whereas seedlings of woody 

species were scarce (Byer and Weaver 1977). After 

nearly 20 years, nine primary forest species comprised 

75 percent of the trees and 85 percent of the biomass 

(Weaver 1990). Recovery was slow, and at the observed 

rate would span about two centuries before the initial 

aboveground biomass would be restored. 

Vegetation Gradient 

Thirty plots, 50 by 10 m in size (or 1.5 ha in total), 

were systematically sampled in the Bafio de Oro to 

provide data on forest structure and species composition for all trees 24.1 cm in d.b.h. The plots ranged in 

elevation from 350 to 1,025 m and were stratified in 

groups of three according to topography (ridge, slope, 

and valley) at each elevation. Height of the dominant 

and codominant stems decreased along the gradient 

from 23 m at a 350-m elevation to 5 m at a 1,025-m 

elevation, with the most and least pronounced 

decreases apparent on ridge and valley topography, 

respectively (fig. 12). Although variation in tree height 

is considerable, the tallest trees in the tabonuco forest 

(5600 m) are on ridges, and the tallest trees in the 

dwarf forest (2 900 m) are found in valleys. 

The diameters of the largest recorded stems in the 

dwarf, colorado, and tabonuco forests were about 50 

cm, 100 cm, and 95 cm, respectively. Only 32 percent of 

the dwarf forest trees are 110 cm in d.b.h., whereas the 

comparable figures for the coIorado and tabonuco forest 

are 60 and 65 percent, respectively (fig. 13). The tallest 

trees in the dwarf, colorado, and tabonuco forests measured about 15 m, 21 m, and 28 m. Only 10 percent of 

the dwarf forest trees were >9 m tall, whereas comparable data for the colorado and tabonuco forests were 44 

percent and 54 percent (fig. 14). 

The mean basal area for all plots combined was 44 +- 

3 m2/ha, and the mean total aboveground biomass, 

based on regression equations, was 205 rt 27 tha. 

Basal area and biomass estimates for the respective 

forests are biased, especially for ridge plots at lower 

elevations, because the sampling procedure used small, 

closed-canopy plots. These plots tend to have a greater 

number of stems than larger areas, which include natural breaks, or gaps, in the canopy. 

Species composition according to elevation, topography, and forest type is tentatively presented in table 8. 

Given that the entire sample of the area was limited to 

only 1.5 ha, this table is not intended to be used 

A RIDGE 

0 SLOPE 

2 0 VALLEY 

\ 

5 

h 

2 9 '5 

$ 

iu 

iu 

2 10 

Z 

5 

0 

ELEVATION (m) 

Figure 12.- The height of dominant and codominant trees by topography and elevation on closed 

canopy 50- by 10-m plots in the Bario de Om Natural Area. 
Walking Clusia grisebachiana possibly the res 

Natural Area. 

iuk of past hurricane impacts in the Baria de Om 

rigorously to determine species distributions, but 

rather is to be used as a guide. In general, the f~st 30

species ranging from Pterocarpus oficinalis through 

Alchornea latifolia are principally tabonuco forest species. The 12 species from Haenianthus salicifolius 

through Ternstroemia luquillensis are mainly dwarf 

forest species. The remaining 27 species in between are 

principally colorado forest species, or are well distributed throughout the Bafio de Oro. 

Among the larger shade tolerant species, Prestoea 

montana, Micropholis garciniaefolia, and Calycogonium squamulosum are well distributed in all three 

forest types. Cecropia peltata, a shade-intolerant species, is also well distributed. Among the smaller tree 

species, Ocotea leucoxylon and Psychoteria berteriana 

are found throughout the area. Ocotea spathulata and 

Tabebuia rigida, shade-tolerant species normally confined to the upper two forest types, are also present in 

the tabonuco forest. This is probably due to the high 

rainfall that characterizes the Baiio de Oro. 

Information borrowed from several other LEF studies outside of the Baiio de Om provides insights regarding changes in forest structure and dynamics over the 

gradient from the 150-m LEF border to the 1,050-m 

mountain summits. Future studies may confirm similar relationships within the Bafio de Oro. 

Structurally, the number of trees per unit area and 

the soil organic matter content increase with elevation 

(table 9). In contrast, specific leaf area, canopy height, 

typical d.b.h. range, forest volume and biomass, leaf 

area index, and species richness all decrease with an 

increase in elevation. 

Forest dynamics also show changes with elevation 

(table 10) Weaver and Murphy 1990). Mortality rates 

in palm and tabonuco forests measured over 30 years 

exceeded ingrowth, while in the colorado forest mortality rates measured over 35 years were equal to 

ingrowth. These differences may be due to more rapid 

growth and competition among stems in the lower forests. Loose litter tends to increase with elevation except 

in the dwarf forest. In contrast, litterfall decreases 

with elevation except in the palm forest (Frangi and 

Lugo 1985). Litter turnover rate also decreases with 

elevation. Standing herbivory and herbivory rate 

records are incomplete and thus difficult to compare. It 

appears, however, that both decrease with an increase 

in elevation. Diameter, volume, and biomass increment 

all decrease with elevation as does aboveground net 

primary productivity. 

The structural and floristic impoverishment of forests with an increase in elevation on small, wet, tropical 

mountains, such as the isolated, coastal mountains in 

the West Indies, has been attributed to the Massenerhebung effect, a phenomenon first recorded in the 

European Alps. Many investigators have proposed 

ideas to account for this phenomenon in Puerto Rico 

and elsewhere, among them, saturated soils and 

reduced root respiration (Holdridge 19671, impeded soil 

drainage (Wadsworth and Bonnet 1951), high winds in 

summit areas, leaching of the soils combined with high 

fog incidence (Baynton 19691, reduced transpiration 

rates (Beard 1944, Leigh 1975, Odum 1968), and fog, 

high soil water content, and reduced mineralization of 

organic matter (Grubb 1971). 
DWARF FOREST 

Y 

0 600 COLORADO FOREST 

2 

d 500 

C 

\ 

400 

L 

I. 

2; 3 00 

3 111 200 

Q 

q I00 

k' 

90 

1,500 ........... 

.............. ........... ......... 

.:...: ..:.: .,:.> ........... ............ 1,400 ........ 

.......... .: ............. n .:...:;.:.:.i... DWARF FOREST 

HEIGHT CLASS (m) 

Figure 14.- Height class distributions of trees on closed canopy 50- 

by 10-m-temporary plots in the tabonuco, colorado, and 

dwarf forests of the Baiio de Om Natural Area. 

DIAMETER CLASS (cm) 

Figure 13. -Diameter class distributions of trees on closed canopy 50- 

by 10-mplots in the tabonwo, cobrado, and dwarf forests 

of the Balio & Om Natural ha. 

Current Research Activities 

Long-nrrn Monitoring on TR-1. - Known forestry research activities began in the Baiio de Oro with 

the 1937 timber cruise. The cruise records were used to 

characterize species composition and forest structure 

and are still available at the International Institute of 

Tropical Forestry. 

Beginning in the mid-1940's, only a decade after the 

passage of Hurricane San Cipriano directly over the 

LEF, several permanent plots were established 

throughout the forest to determine species compositions and diameter growth rates (Crow 1980, Lugo and 

Brown 1981, Wadsworth 1950a, Weaver 1983). One of 

these, TR-1, is located at a 350-m elevation in the 

northern part of the Baiio de Oro. The 0.4-ha plot is 

centered on a ridge and contains tree species characteristic of the tabonuco, colorado, and dwarf forests. 

First sampled in 1946, the plot was remeasured in 1951, 

1956, 1966, 1977, and again in 1988 and 1990, just 

before and immediately after the passage of Hurricane 

Hugo in September 1989. With the passage of time, the 

plot record has become a valuable chronology of 

changes in species composition, forest structure, and 

dynamics in response to Hurricane San Cipriano of 

1932 (table 11) (Weaver 1983). 
W Table 8. -0cc~~rrence of tree species in the Barb de Om Natural Area by elevation, topography, and forest type.* Species are ranked from those most common at lower elevation to those most 

common at higher elevation 

Elevation (Meters) Total Percent by topography Percent by forest typet 

Soecies 350 450 550 600 650 700 750 850 950 1050 NO. Percent Valley Slope Ridge Tabonuco Colorado Dwarf 

Ptemcarpus officinalis 

Andira inermis 

Guatteria caribaea 

Ixora ferrea 

Laplaceaportoricensis 

Phyllanthus nobilis 

Buchenavia capitata 

Rneediaportoricensis 

Mecranium amygdalinum 

Hirtella rugosa 

Inga laurina 

Manilkara bidentata 

Meliosma herbertii 

Cassipourea guianensis 

Guarea guidonin 

G. ramiflora 

Antirhea obtusifotia 

?hbebuia hetemphylla 

Homalium racemosum 

Drypetes glauca 

Menendezia urbanii 

Cordia sulcata 

Myrcia deflexa 

Ocotea moschata 

Eugenia stahlii 

Palicouma riparia 

Slwnea berteriana 

Dacryodes ercelsa 

Didymopanax momtotoni 

Alchornealatifolia 

Miconia tetrandra 

Daphnopsisphilippiana 

Cmtonpoecilanthus 

Ditta myricoides 

Cyrilla racemiflom 

Sapium laurocemsus 

Rondeletiaportoricensis 

Magnolia splendens 

Coniia borinquensis 

Prestoea mntana 
Bble 8. -Occurrence of tree species in the Bar% & Oro Natural Area by elevation, topography, and forest type.* Species are ranked from those most common at lower elevation to those most 

common at higher elevation - Continued. 

Elevation (Meters) Total Percent by topography Percent by forest typet 

S~ecies 350 450 550 600 650 700 750 850 950 1050 No. Percent Vallw Slow Ridee Tabonuco Colorado Dwarf 

Ocotea leucmylon 

Cecropia peltata 

Citharaylurn caudoturn 

Miconia Iaevigata 

Eugenia eggersii 

Xylosma schuaneckeanurn 

Miconia prasina 

'lbrralbasia cuneifolin 

Ardisia luquillensis 

Micropholis garciniaefdia 

Psychofria berteriann 

Clusia krugiana 

Calycogoniurn squarnubsurn 

Hedyosrnurn arbnrescens 

Byrsonima wadswrthii 

Myrcia fallax 

Miconia pachyphyllo 

Haenianfhus salicifdiius 

Marliern sintenisii 

Ilhbebuia rigida 

Grnrnrnaa'enia sintenisii 

Ocotea spathulata 

Cyothea arborea 

Iler sideraryloides 

Eugenia borinquensis 

Calyptranthes krugii 

Alsophilo bryophila 

Miconia sintenisii 

lkmstroernia luauillensis -- 

Number of stems 

Number of stemslha 

Number of species 

SDecies oer foreat 

'Survey conducted an 30 temporaty plots 50 by 10 m in size. 

?Forest types: tabonurn, 360 to 600 m; Colorado, 600 to 750 m; and dwarf 850 to 1050 m. Percentages refer to proportions of species found on each topographic position or forest type. 
Table 9.-Comparison of stand structure for four forests within the Luquillo Mountains* 

Forest type Structural characteristics 

Tabonuco Palm Colorado Dwarf 

Treeslha 

Canopy height (m) 

Typical d.b.h. range icm) 

Basal area (mzlha) 

Aboveground volume (m31ha) 

Aboveground woody biomass (tlha) 

Leaf biomass (tlha) 

Leaf area index (m2/m2) 

Specific leaf area (cmzlg) 

Standing herbivory (percent) 

Total tree species 

Tree specieslha 

Soil organic matter (tlha) 

*Benedict 1976; Crow 1980; Frangi and Lugo 1985; Medina and others 1981; Odum 1970; Odum 

and Ruiz-Reyes 1970; Ovington and Olson 1970; Wadsworth 1950a; Weaver 1972a, 1983; Weaver and 

Murphy 1990. 

?All trees 24 cm in diameter. 

*All trees 2 1 cm in diameter. 

§Blank fields indicate missing data. 

aTop 25 cm of soil. 

**Top 100 cm of soil. 

ttTop 50 cm of soil. 

Table 10. -Comparison of stand dynamics for four forests within the Luquillo Mountains* 

Forest type? Dynamic feature 

Tabonuco Palm Colorado Dwarf 

Ingrowth (stemslhalyr) 

Mortality (stemslhalyr) 

Litterfall (tlhalyr) 

Leaf 

wood 

Flower 

Fruit 

Mischeous 

Loose litter (tlha) 

Herbivory rate (tlhalyr) 

Litter turnover rate 

Mean d.b.h. growth (cmlyr) 

Total aboveground growth 

Woody volume (m31halyr) 

Woody biomass (tlhalyr) 

Total aboveground net primary 

productivity (rlhalyr) 

*Adapted from: Benedict 1976; Briscoe and Wadsworth 1970; Frangi and Lug0 1985; Odum 1970; Reagan 

and others 1982; Wadsworth 1951,1952; Weaver 1983; Weaver and Murphy 1990; Weaver and others 1986. 

tPlot elevations: tabonuco, 450 m; palm, 750 m; colorado 750 m; and dwarf 1,000 m. 

*Blank fields indicate missing data. 

$Flowers and fruits combined. 
able 11. -Stand table-ranking of species by density and basal area (BA) dominance on permanent plot TR-1 from 1946 through 1976 on a hectare 

basis 

1946 Ingrowth 1946-76 Mortality 1976 

Species No. of stems BA No. of stems BA No. of stems No. of stems BA 

Meters Meters Meters 

Dacryodes excelsa 215 20.93 5 0.01 30 190 24.30 

me last om at ace^ Spp. 208 1.04 .... * .... 120 88 1.80 

Prestonea montana 195 3.36 28 .37 40 183 3.30 

Micropholis garciniaefolia 120 3.22 2 .OO 27 95 2.90 

Octoea mschata 105 1.14 10 .01 55 60 .64 

Calycogonium squamulosum 95 .50 5 .01 45 55 .40 

Sloanea berteriam 82 1.00 10 .03 40 52 .3 1 

Didympanax mrototoni .... .... 75 .75 20 55 2.10 

Cordia borinquensis 70 .21 5 .01 55 20 .07 

Hirtella rugosa 62 .25 22 .04 13 7 1 .30 

.... .... .... .... Psychotria berteriana 60 .12 60 

Cordia .... .... sulcata 52 .19 34 18 .12 

.... .... Laplacea portoricensis 50 .32 38 12 .13 

Cecropia .... .... peltata 48 .45 38 10 .36 

Meliosma herbertii 32 .27 12 .02 4 40 .37 

.... .... Inga laurina 28 .31 13 15 .44 

.... .... Alchornea latifolia 28 .30 12 16 .60 

Magnolia .... .... spkndem 25 2.51 12 13 2.60 

Rheedia portoricensis 25 .10 15 .02 2 38 .11 

Manilkara bidentata 25 .08 2 . 00 2 25 .18 

Wbuia heterophylla 22 .ll 5 .01 14 13 .09 

Matayba .... .... .... domingensis 18 .20 18 .77 

Cyrilla .... .... racemiflora 15 2.91 4 11 3.10 

.... .... Bucherrwia capitata 12 1.30 2 10 2.50 

Homalium .... .... .... racernosum 12 .44 12 .87 

.... .... .... .... Cyathea arborea 10 .07 10 

.... .... .... Eugenia borinquensis 8 .40 8 .50 .... .... .... Byrsonima wadsworthii 8 .35 8 .40 

.... .... Andira inermis 8 .09 3 5 .10 

.... .... .... lktragastris balsamifem 8 .03 8 .07 .... .... .... .... Myrcia splendem 8 .02 8 .... .... .... .... Hedyosmum arborescens 8 .01 8 

.... .... .... Alchorneopsis portoricensis 5 .10 5 .45 

Casearia sylvestris 5 .O1 2 .oo 5 2 .oo 

Daphmpsis philippiam 5 .01 2 .OO 5 2 . 00 

.... .... .... Beilschmiedia penduln 2 .37 2 1 .oo .... .... .... Guakteria caribma 2 0.16 2 0.18 

.... .... .... .... Solnnum rugosum 2 .02 2 

.... .... .... Croton poecilnnthus 2 .01 2 .03 

.... .... .... Byrsonima coriaceae 2 .01 2 .02 

.... .... .... .... Sapium laurocemsus 2 .01 2 

.... .... .... Phyllanthus nobilis 2 .01 2 . 00 

.... .... .... .... Myrcia dew 2 . 00 2 

.... Quamribaea turbinata 2 .OO 2 0.00 4 .01 

.... .... .... Guarea ramiflorn 2 .OO 2 .oo .... .... .... .... Ocotea leucaxylon 2 .OO 2 

.... .... .... .... Byrsonirna coriacea 2 .OO 2 

.... .... .... Antirhea obtusifolia 2 .OO 2 . 00 

.... .... .... Oxandra laurifdia 8 .01 8 .01 

.... .... .... Guareaguidonia 2 . 00 2 .oo .... .... .... Unknown 2 .oo 2 .oo 

Mean total 1778 43.69 139 0.54 729 1188 51.13 

*Blank fields indicate missing data. 
The 30-year partial record shows stand composition in 

1946 and 1976. Mortality exceeded ingrowth, and the 

number of stems decreased considerably over the period 

of measurement. Small secondary trees such as the 

Melastomatacae and Psychoteria berteriana disappeared 

completely. Larger secondary species such as Cecropia 

peltata and Didymopanax morototoni, and several 

Melastomataceae, decreased considerably in numbers. 

Table 12 shows a 30-year record of diameter growth 

by species for all stems that survived the period. A 

gradual slowing of growth is apparent as the trees age 

and the stand closes during recovery. 

Diameter class distributions also indicate changes 

over time (fig. 15). Stems in the smallest two d.b.h. 

classes, between 4.1 and 19.9 cm, decreased by 58 percent and 21 percent, respectively, between 1946 and 

1988. In contrast, the stems in the next two largest 

d.b.h. classes, between 20.0 and 39.9 cm, increased 23 

percent and 57 percent, respectively. Fluctuations in 

classes 240 cm are less evident. These structural 

changes reflect growth after the 1932 hurricane. After 

Hurricane Hugo, the number of stems decreased in all 

diameter classes, most notably in those between 4.1 

and 19.9 cm (fig. 15). 

Table 12. -Mean annual d.b.h. increment by species from 1946 through 1976 on permanent plot TR-I for all trees that survived the entire period 

and range of d.b.h. by species in 1946 

Mean annual diameter increment No. D.b.h. range Species 1946-51 1951-56 1956-66 1966-76 1946-76 

cv* of stems 1946 

................................ Centimeterslyear ................................. Percent+ Centimeters 

Dacryodes ercelsa 0.22 0.13 0.14 0.16 0.16 87 74 4-96 

Mehstomataceae spp. .31 .22 .24 .14 .21 69 35 4-25 

Prestoea montaruz .03 .01 .02 .02 .01 175 62 10-20 

Micropholis garciniaefolia .ll .02 .06 .04 .05 98 37 6-37 

Ocotea moschata .14 .07 .08 .05 .08 67 19 4-28 

Calycogonium squamulosum .10 .05 .08 .03 .06 110 20 4-22 

Sloanea berteriana .10 .08 .12 .06 .09 84 17 4-9 

Didymopanojc mrototoni .62 .42 .28 .12 .31 64 22 5-22 

Cordia borinquensis .02 . 00 .02 .02 .01 118 6 4-10 

Hirtella rugosa .03 .02 .03 .02 .02 98 20 4-13 

Cordia sulcata .06 .02 .05 .04 .04 130 7 4-1 1 

Laplacea portoricensis .24 .09 .12 .08 .ll 90 5 4-12 

Cecropia peltata .80 .25 .38 .15 .35 16 4 6-15 

Meliosma herbertii .10 .06 .09 .04 .07 100 11 4-23 

Inga laurina .15 .15 .22 .10 .14 92 6 6-21 

Alchornea latifolia .49 .29 .24 .03 .21 99 6 7-19 

Magnolia splendens .10 .12 .05 .08 .07 73 5 7-67 

Rheediaportoricensis .03 . 00 .03 .02 .02 140 9 4-9 

Manilkara bidentata .12 .08 .15 .08 .10 54 9 5-9 

'Ihbebuia heterophylla .02 .02 .O1 .05 .02 107 3 5-15 

Matayba domingensis .50 .38 .42 .25 .36 36 7 5-20 

Cyrilla racemiflom .22 .21 .18 .18 .19 64 4 39-74 

Buchenavia capitata .79 .62 .45 .38 .51 34 4 27-56 

Homalium racemosum .38 .21 .32 .16 .25 84 5 8-37 

Eugenia borinquensis .12 .08 .15 .02 .09 87 3 23-29 

Byrsonima wadsworthii .02 .02 .10 .02 .04 58 3 11-34 

Andira inermis .15 .02 .10 .05 .08 24 2 12-15 

Dtragastris balsamifera .07 .02 .07 .20 .ll 42 3 5-12 

Alchorneopsis portorkernis .85 .65 .80 .35 .61 7 2 7-2 1 

Beilschmiediapendula .60 .80 .58 1.43 .92 .... 1 43 

Guatteria caribaea .05 .10 .12 .OO .06 .... 1 28 

Croton poecilanthus .10 .lo .22 .16 .16 . . . . 1 7 

Byrsonima coriacea .15 .OO .15 .10 .10 . . . . 1 7 

Phyllnnthus rwbilis .05 .05 .02 .08 .05 .... 1 6 

Quararibaea turbinata .05 .05 .OO . 00 .02 .... 1 5 

Guarea ramiflora . 00 .OO .02 .OO .01 .... 1 5 

Antirhea obtusifolia .05 . 00 .02 .02 .02 .... 1 4 

MeanlTotal* 0.125 0.075 0.085 0.058 0.080 .... 418 4-96 

0.134 0.085 0.095 0.065 0.088 138 356 4-96 

*CV = coeMicient of variation. 

tBlank fields indicate missing data. 

*Top row includes plam Prestoea montana; bottom row excludes palm. 
I D.B.H. CLASSES (fm) I 

YEAR 

Figure 15. -Diameter class distributions in 7 different years on long-term plot TR-1 in the Barto & Om Natural Area. The 

numbers in the declining sequence from 713 to 332 refer to total stems in the plot. 

Phenology nail. -A trail was established through 

the east fork of the Rio Marneyes in February 1987 to 

monitor the phenology of colorado forest vegetation. 

Ninety-eight individual plants were originally selected: 

14 were Marcgravia sintinisii or Clusia gundlachi, 

common forest vines, and 84 were of 15 tree species 

with d.b.h.'s between 4.3 and 110.0 cm (table 13). 

Monitoring is done twice monthly. The quantity of 

flowers, leaves, and fruits, each rated from 1 through 4, 

are recorded for each plant. Fruit size and ripeness are 

also noted, as are the number of individuals of each 

bird species found using the plants. Unfortunately, several plants were damaged by Hurricane Hugo. These 

should be replaced to maintain the initial representation of plants. 

Ring Formation in Cyrilla Racemiflora. -A 

study was initiated in January 1989 to determine the 

nature of ring formation in Cyrilla racemiflora. One of 

the four sites selected for the study borders the Baiio de 

Oro. Among the parameters being monitored at the 

Baiio de Oro site are rainfall, temperature, branch 

elongation, flowering and fruiting, leaf formation and 

leaf drop, xylem water potential, and xylem cell formation. The study spanned one dry season extending from 

January to late June 1989, with further monitoring in 

October and December 1989 and in June 1990. As sampling continues and the patterns observed in the first 

year are tested against future growth, the periodicity 

of growth ring formation should become clearer. 

In December 1990, the study was expanded to 

include trees on a permanent plot that had been disturbed by Hurricane San Cipriano in 1932 and thinned 

in 1946. Increment borings and ring counts of trees on 

sites with known past disturbance will be used as an 

additional test of the hypothesis that the number of 

rings is indicative of tree age in Cyrilla. Simultaneous 

monitoring of carbon dioxide exchange of Cyrilla leaves 

along with that of xylem water potential is being done 

to clarify the relationship between these parameters. 

Minority Research Program. -Eight separate 

experiments aimed at determining the influences of 

climate, soil fertility, and genome on plant productivity 

are being conducted in the dwarf forest near the border 

of the Baiio de Oro (fig. 2). The research consists of: 

tree growth in fertilized versus control plots, understory responses to fertilization, fine root biomass and 

production observations, litterfall and litter chemistry, 

nutrient cycling via throughfall, nitrogen mineralization and nitrification, wind damage to forest trees, and 

a transplant experiment. 

The tree growth in fertilized versus control plots was 

originally designed to evaluate the effect of nutrient 

availability (N-P-K plus micronutrients) on forest productivity such as diameter increment, twig growth,.and 

new leaf development. Given that Hurricane Hugo 

damaged the plots, the experiment now deals with a 

forest recovering from disturbance rather than with a 

mature forest. The revised experimental design places 
Table 13. -Species inclhd in the phenological study in the East Fork watershed of 

the Rio Mameyes 

Species Number of D.b.h.* 

individuals Minimum Maximum 

Calycogonium squamulosum 1 12.0 12.0 

Clusia gundlachii + 2 . . . . .... Dacryodes 0u:elsa 10 26.0 85.0 

Eugenia stahlii 2 24.0 25.0 

Haenianthis salicifolius 5 8.0 55.0 

Inga laurinn 5 16.0 75.0 

Laplacea portoricensis 1 13.0 13.0 

Magnolia splendens 10 41.0 85.0 

Marcgravin sintenisiit 12 .... . . . . 

Mat* domengensis 5 34.0 43.0 

Micropholis garciniaefolia 11 22.0 55.0 

Ocotea portoricensis 1 18.0 18.0 

0. spathulata 3 19.0 40.0 

Prestoea mntana 10 11.5 19.0 

Psychotrai berteriana 1 4.3 4.3 

Rheedia portoricensis 8 5.0 14.0 

Sloanea berterinna - 11 15.0 110.0 

Total 98 

*Blank fields indicate missing data. 

Vines; all remaining species are trees. 

greater emphasis on indices of productivity such as 

canopy recovery (leaf area index), sprouting, and 

recruitment and growth of seedling and saplings. 

Understory responses to fertilization are being 

assessed on treatment and control quadrats located 

within the fertilized and control plots. Vegetation cover, 

height, and basal diameters of marked tree seedlings 

are being measured every 6 months. 

Fine root biomass and production are being observed 

on the treatment and control plots. Six cores are 

sequentially taken in the upper 10 cm of mineral soil 

and litter layers on each plot at 2-month intervals. 

Changes in the live and dead fine root mass between 

sampling dates are used to determine root production, 

mortality, and decomposition in each experimental 

plot. 

Litterfall and litter chemistry are being examined to 

determine the influence of nutrient availability on the 

production of canopy litter, its nutrient concentrations, 

and the efficiency of nutrient use. Litter derived as a 

result of the hurricane is also being examined in the 

same manner. Litter baskets are sampled every 2 

weeks, and the collections are sorted into fractions and 

analyzed for nutrients. Fresh leaf samples of a common 

dwarf forest tree, Tabebuia rigida, are simultaneously 

collected on each plot. 

Nutrient cycling via throughfall is being assessed by 

using 3-day sampling periods twice monthly on the 

treatment and control plots. Nitrogen mineralization 

and nitrification are being estimated by in situ incubation of intact soil cores every 6 months. 

Wind damage to trees is being assessed on forest 

plots established before Hurricane Hugo to answer 

four questions: (1) Can damage be predicted by either 

abiotic factors (for example, aspect) or biotic factors 

(for example, tree diameter)? (2) Is initial tree recovery 

related to damage? (3) Do tree species recover from 

damage at different rates? (4) Does the forest recover 

via species turnover and succession or via direct 

regeneration of canopy species? 

The transplant experiment is designed to explore two 

questions: (1) Are there genetic differences in growth 

characteristics between populations of tropical plant 

species growing at low and high elevations? (2) Does 

wind affect the growth of plants in the dwarf forest? 

Reciprocal transplants of clones of key forest species 

are used to detect genetically determined differences in 

productivity between seedlings in the dwarf forest and 

those at lower elevations in the LEF. The effect of wind 

on productivity in the dwarf forest is being examined 

by comparing growth in plots protected by barriers 

versus growth in exposed plots. 

Water Chemistry. -Weekly sampling of streamflow 

was initiated just above the USGS (U.S. Geological 

Survey) gauge at Puente Roto in May 1989 as part of 

the long-term ecological research in the LEF. The purpose of the study is twofold: first, to quantify dissolved 

and fine particulate exports from the Rio Mameyes 

watershed, which includes the Bisley experimental 

watersheds, and drainage from the Baiio de Om; and 

second, to determine the effects of watershed scale on 

exports by comparing the Puente Roto data with those 
from smaller watersheds in the same basin. The dissolved chemistry parameters being measured are: pH, 

ortho-P04, NO,-, NH4+, organic C, organic N, C1-, 

SO4-2, SiO,, Na+, K+, Ca+2, and Mg+2. Particulate 

measures include N, C, and total sediments. Observations will continue for several years. 

FAUNA 

From August 31, 1984, through February 8, 1985, a 

general survey of animal species was conducted in the 

Baiio de Oro by the University of Puerto Rico Biology 

Department. The purpose was to determine the diversity and distribution of the fauna in each of the four 

forest types and in the streams. Samples were collected 

in each of the four forest types and from the streams 

flowing out of the upper reaches of the Rio Mameyes. 

The results, based on observations made at 13 sampling 

stations (fig. 2), are shown in tables 14 and 15. 

Vertebrates 

One species of fish was observed but not identified. 

This was probably the green stream goby (Sicydium 

plumieri), a diadromous fish reported to be in the headwaters of the Rio Mameyes (Erdman 1986, Wiley and 

Bauer 1985). The goby is common in streams of the 

West Indies (Erdman 1961). 

Eleven of the 14 amphibians reported for the LEF 

(Brown and others 1983) were collected. These included 

1 toad and 10 endemic frogs of the genus Eleutherodactylus. Of the 13 reptiles identified, 2 were geckos, 8 

were lizards (mainly of the genus Anolis), and 3 were 

snakes. Epicrates inorncltus, the Puerto Rican boa, is 

classified as a rare and endangered species. 

Twenty-one of the 66 species of birds on the LEF 

checklist (Wiley and Bauer 1985) were observed during 

the survey. Other species reported by qualified personnel have been added to the list (table 15). Two introduced mammals, the mongoose and the black rat, were 

%ble 14.-Animal species recorded in the Bario de On, Natural Area (except bird spec*) 

Habitat type' 

Classification Endemic* TCPDW 

Phylum Platyhelminthes 

Class nrOrder Tricladida 

Family Geoplanidae 

1. Geoplana sp. 

Phylum Nematoda 

Class Adenophorea (Aphasmidea) 

Order Dorylaimida 

Family Dorylaimidae 

1. Dorylaimus sp. 

Class Secernentea (Phasmidea) 

Order Qlenehida 

Family Aphelenchoididae 

2. Aphelenchoides sp. 

Family Heteroderidae 

3. hiebidogyne sp. 

Phylum Annelida 

Class Oligochaeta 

order Haplotaxida 

1. Haplotoxid sp. 1 (giant form) 

2. Haplotoxid sp. 2 (violet form) 

3. Haplotoxid sp. 3. (white form) 

Class Hirudinea 

Order (?I 

Family (?) 

4. Hirudinid sp. 1. (terrestrial form) 

Phylum Mollusca 

Class of Gastropods 

Subclass Prosobranchia 

Order Archaeogastropoda 

Family Helicinidae 

1. Alcadin alta 

2. A. striata 

X 

XXX 

X 

0 X 

0 XXXX 
Table 14.-Animal species recorded in the Bario de Om Natural Area (erccept bird species)-Continued 

Habitat typet 

Classification Endemic* TCPDW 

Order Mesogastropoda 

Family Cyclophoridae 

3. Megalomastoma croceum 

4. M. uerruculosum 

Family Pomatiidae 

5. Chondmpoma yunkei 

Subclass Pulmonata 

Order Stylommatophora 

Family Bulimulidae 

6. Gaeotis nigrolineata 

Family Camaenidae 

7. Camcolus caracdln 

8. Polydontes acutangula 

9. l? luquillensis 

Family Clausiliidae 

10. Nenia tridens 

Family Haplotremidae 

11. Austrosolenites alticola 

Family Oleacinidae 

12. Oleacina glabm 

13. 0. playa 

14. Varicelln portoricensis 

Family Sagdidae 

15. Pldysuccinea portoricensis 

16. Succinea hyalina 

Family Subulinidae 

17. Obeliscus terebraster 

XXXX 

X X 

XXXX 

Order Systellommatophora 

Famly Verunididae 

18. Vagragrnulus plebleius 

Phylum Onychophora 

Family Peripatidae 

1. Peripatus juanensis 

Phylum Arthmpoda 

Subphylum Chelicerata 

Class Arachnids 

Order Amblypygi 

Famly Phrynidae 

1. Phrynus longipes 

Order Araneae 

Suborder Orthognatha 

Family Barychelidae 

2. Psalistops corozali 

Family Dipluridae 

3. Accola spirwsa 

Famly Theraphosidae 

4. hie* laeta 

5. cyrtopholis portoricae 

6. Ischrwcolus cukbrae 

7. Stichophtus culebrae 

Suborder Labidognatha 

Division Cribellata 

Family Uloboridae 

8. Miagmmmopes ciliatus 

9. M. mditus 

Division Acribellata 

Family Anyphaenidae 

lo. Wulfila tropica 

11. U! mmropalpus 

Family Araneidae 

Subfamily Gasteracanthinae 

12. Gastermantha tetmcanthn 

XXX 

XXXX 

X X 

X 

XXX 

X 

XXXX 

X 
Table 14. -Animal species recorded in the Bario de Oro Natural Area (except bird species)- Continued 

Habitat type+ 

Classification Endemic* 

TCPDW 

Subfamily Araneinoe 

13. Edricus crassicauda X X 

Subfamily Metinae 

14. Leucage regni 0 XXX 

15. L. venusta X X 

16. Pseudometa hameta X X 

Family Clubionidae 

17. Corinna jayuyae 0 x X 

18. C. abnormis 0 X 

Family Ctenidae 

19. Oligoctenus ottleyi 0 X 

Family Pholcidae 

20. Modisimus ccwaticus 0 X X X 

21. M. modanus 0 X X X 

22. M. s~oculotus 0 X X 

23. M. signatus 0 XXXX 

Family Salticidae 

24. Corythalia glorim 0 X X X 

25. Emanthis portoricensis 0 XXXX 

Family Selenopidae 

Family Sparassidae 

27. Pseudosparianthis jayuyae 0 X 

28. Stassina portoricensis 0 XXXX 

Family Tetragnathidae 

29. Tetragnatha tenuissima X X 

Family Theridiidae 

30. Lithyphantes septemmaculotus XXX 

Family Theridiosomatidae 

31. Wendilgardin theridionina 0 X X 

Family Zoridae 

32. Zorid sp. 1 X X 

Order Opiliones 

Suborder Laniatores 

Family Phalangodidae 

33. Metapellobunus unicolor 0 X 

34. Pseudomitmcems minitus 0 X X 

Order Scorpiones 

Family Buthidae 

35. Titus obtusus 0 X X X 

Subphylum Crustacea 

Class Malacostraca 

Order Decapoda 

Family Atyidae 

1. Atya lanipes 0 X X 

2. Micratyapoeyi X X 

3. Xiphocaris elongata X X 

Family Palaemonidae 

4. Macrobrachium carcinus X X 

Family Pseudothelphusidae 

ilobocmc sinuatifmm 0 

Order Isopoda 

Family Cubaridae 

6. Sphaemniscus portoricensis X X 

Family Oniscidae 

6. Philocia richmndi XXXX 

7. Synumps granulotus XXXX 

8. Rhysotus turgifmns XXX 

9. Porcelloides pruinosus X 

Subphylum Uniramia 

Chss Chilopoda 

Subclass Anamorpha 

Order Scutigemmorpha 

Family Scutigeridae 

1. Antillona portoricensis 
Table 14. -Animal species recorded in the Bario de Om Natural Area (wept bird species)- Continued 

Classification 

Habitat type+ Endemic* 

TCPDW 

Subclass Epimorpha 

Order Scolopendromorpha 

Family Cryptopidae 

2. Cryptops bivittatus 

3. Newportia longitarsis 

4. Newportia n. sp. (M.S.) 

5. Newportia n. sp. (M.S.) 

6. Newportia sp. (juveniles) 

7. Scolopocryptops ferruginew 

8. S. melamstomus 

Family Scolopendridae 

9. Scolopendra akernans 

10. Otostigmus caraibicus 

Order Geophilomorpha 

11. Geophilomorph sp. 1 

12. Geophilomorph sp. 2 

13. Geophilomorph sp. 3 

14. Geophilomorph sp. 4 

15. Geophilomorph sp. 5 

Class Diplopods 

Subclass PeniciUata 

Order Polyxenida 

Family Lophoproctidue 

1. Lophoturus niveus 

2. hphoturus sp. 

Subclass Pentozonia 

Order Glomeridesmida 

Family Glomeridesmidae 

3. Glomeridesmus marmoreus 

Order Polydesmida 

Suborder Polydesmidea 

Family Pyrgodesmidae 

4. Docodesmus vidalis 

5. Docodesmus sp. 

6. lomus incisus 

7. Iomus sp 

8. Liomus obscurus 

9. Liomus sp 

Family Chelodesmidae 

10. Ricodesmus stejneri 

Family Fuhrmannodesrcidoe 

11. Cryptogonodesmus rolleis 

Family Haplodesmidae 

12. Cylindrodesmus caraibicus 

Order Spirobolida 

Family Spirobolellidae 

13. Spirobolellus richmondi 

14. Spirobolellus n. sp. 1 

15. Spirobdellus n. sp. 2 

Order Spirostreptida 

Family Pseudononnolenidae 

16. Epinannolene trinidadensis 

17. Epinannolene sp. 

18. Epinannolene sp. 

Order Stemmiulida 

Family Semmiulidae 

19. Prostemmiulus n. sp. 1 

20. Prostemmiulus n. sp. 2 

21. Prostemmiulus sp. 1 

Order Siphonophorida 

Family Siphonophoridae 

24. Siphonophora portoricensis 

XXX 

X 

0 XXXX 

0 X X 

X 

0 XXXX 

0 X X 

XXXX 

XXXX 

X X 
Table 14.-Animal species recorded in the Bario de Oro Natural Area (except bird species)-Continued 

Habitat type+ 

Classification Endemic* TCPDW 

Class Symphyla Family Scutigerellidae 

1. Hanseniella sp X 

Class Inseda 

Order Orthoptera 

Family Blattidae 

5. Pelmatosilpha coriacea 

6. Neoblatella borinquensis 

Order Isoptera 

Family Termitidae 

19. Nasutitermis costalis 

Family Kaotermitidae 

21. Glyptotermes rubescens 

Order Hemiptera 

Family Notonectidae 

29. Buenoa rnacrophthalrna 

Family Veliidae 

30. Rhagovelia collaris 

Order Coleoptera 

Family Scarabeidae 

31. Phyllophaga yunqueana 

Order Diptera 

Family 'hchinidae 

Ormia punctata 

Order Lepidoptera 

Family Danaidae 

41. Dams plerippus 

Family Megalopygidae 

43. Megalo~zyge kkrgii 

Family Satyridae 

44. Cdisto nubila 

Family Sphingidae 

45. Herse cingulota 

Order Hymenoptera 

Family Apidae 

46. Apis rnellifem 

Family Formicidae 

Subfamily Dolichoderinae 

47. Iridonynnex dkus 

Subfamily Formicinae 

48. Myrmelachista ramdorum 

49. Pardrechina longicornis 

Subfamily Myrmicinae 

50. Macromischa isabellae 

53. Solenopsis geminata 

Subfamily Ponerinae 

57. Ponem opaciceps (Juan H. Opaciceps) 

Family Psarnmocharidae 

58. Pepsi ap. 

XXX 

XXXX 

Phylum Chordata 

Class Osteichthyes 

Order 

Family 

1. Unidentified sp. obs. 

Class Amphibia 

Order Anura 

Family Bufonidae 

1. Bufi marinus 

Family Leptodactylidae 

2. Eleutherodactylus coqui 

3. E. eneidae 

4. E. portoricensis 

5. E. richmondi 

6. Leptodactylus albilnbris 

0 XXX 

0 X 

0 X 

0 X 

0 X 
Tmble 14.-Animal species reconled in the BaiLo de On, Natural Area (except bird species)-Continued 

Habitat type+ Classification Endemic* 

TCPDW 

Class Reptilia 

Order Squamata 

Suborder Sauria 

Family Gekkonidae 

1. Sphaerodactylus khberi 

2. S. macrolepsis grandisquamis 

Family Anguidae 

3. Diploglossus pleei 

Family Iguanidae 

4. Anolis c. cristatelus 

5. A cuuieri 

6. A. ewrmani 

7. A. krugii 

8. A. gundlochi 

9. A. stratulus 

10. A. occultus 

Suborder Serdentes 

Family Boidae 

11. Epicrates inornotus 

Family Colubridae 

12. Alsophis portoriensis 

13. Arrhyton eriguum stahli 

Class aves* 

Class Mammalia 

Order Carnivora 

Family Viverridae 

1. Herpestes javanicus 

Order Rodentia 

Family Muridae 

2. Rattus raftus 

*Species endemic to Puerto Rico indicated by 0. 

+Habitat types: T = tabonuco forest; C = colorado forest; P = palm forest; D = dwarf forest; and W = fresh water. 

X indicates in which habitat species occurs. 

*Refer to Table 15. 

also found. Eleven species of native bats are known to 

live in some part of the LEF (Brown and others 1983, 

Starrett 1962)' but none were observed during the survey. 

Bat Study.- One-half of Puerto Rico's 14 bat species are found in the tabonuco forest (Willig and Gannon 1991). Stenoderma rufum, a frugivorous species 

endemic to Puerto Rico and the U.S. Virgin Islands, 

comprises at least 25 percent of the individuals within 

the LEF's tabonuco forest. Other species include 

Artibeus jamaicensis, a frugivore, and Monophyllus 

redmani, a nedivore. 

The foraging movements of bats are instrumental in 

the spatial and genetic structure of plant communities 

through the dispersal of seeds and pollen. Moreover, 

they respond to changes in the structure and species 

composition of the forest after major storm events. 

Hurricane Hugo had numerous effects on bat populations. Artibeus jamaicensis and S. rufurn decreased in 

numbers and M. redmani increased. The major objective of the study was to determine the effects of the 

hurricane on bat ecology. Specifically, the community 

composition, population levels, size of the home range, 

bat numbers, fidelity to feeding areas, commuting distances traveled, and demographic structure were investigated. 

Black Rat Study. - Predation of Puerto Rican parrot eggs by black rats (Raitus rattus), observed years 

ago (Rodriguez-Vidal 1959), prompted an investigation 

of rat reproductive chronology, population fluctuations, 

and habitat use in the vicinity of active nesting sites 

between 1982 and 1985 (Walker Layton 1986, Zwank 

and Walker Layton 1989). Peak sexual activity occurred 

in June with peak populations observed from July 

through September. Density estimates ranged from 70 

to 280 rats per hectare with the lows recorded in late 

winter and early spring prior to the breeding season. 

Radio tracking and snap trapping in trees and on the 

ground indicated that rats appear to be primarily 

arboreal during daylight hours and spend time on the 

ground at night. Snap trapping at three different elevations in the Bafio de Oro indicated denser rat populations in the dwarf forest than in either the colorado or 

tabonuco forests. 
Table 15.-Checklist of birds in the Bario a% Om Natural Area 

Common English name Common Spanish name Scientific Name Status Occurrence Habitat 

in LEF* in LEFS preference** 

Green-backed heron Martinete Butorides striotus T c T,C,[RI 

Sharp-shinned hawk* Halc6n de Sierra Accipiter striotus R U T,C 

Broad-winged hawk* Guaraguao de Bosque Buteo platypterus R c T,C 

Red-tailed hawk Guaraguao Colirrojo B. jamaicensis R c T,C,P,(D) 

Merlin Halc6n Migratorio Falco columbarius T u T,C,(P) 

Peregrine falcon Halc6n Peregrinus I? peregrinus T u T,C,(P) 

Spotted sandpiper Playero Coleador Actitis macularia T c T,C,P, CRI 

Scaly-naped pigeon Paloma Turca Columba squamosa R C T,C,P,D 

Ruddy quail-dove Paloma Perdiz Rojiza Geotrygon montana R C T,C,P,Plant 

Puerto Rican parrot? Cotorra de Puerto Rico Amazon vittota R R T,C,P 

Puerto Rican lizard-cuckoot Pajaro Bobo Mayor Saumthera uieilloti R C E,Plant, T,C,P,D 

Puerta Rim screech-owl? Mucaro de Puerto Rim Otus nudipes R C T,C,P,Plant 

Black swift Vencejo Negro Cypseloides niger T c T,C,P,D 

Antillean mango Zumbador Dorado Anthracothorax dominicus R R E,Plant 

Gwn mango* Zumbador Vefde A. viridis R c T,(c) 

Puerto Rican emerald* Zumbadorcito de Puerto Rico Chlorostilbon rnaugaeus R c (T),C,P,D 

Puerto Rican todyt San Pedrito lbdus micanus R C T,C,P,D 

Puerto Rican woodpecker+ Carpintem de Puerto Rim Melamrpes portoricensis R c Pht,T,C,P,(D) 

Gray kingbird Pitirre 7)rannus dominicenszs R U E,Plant 

Cave swallow Golondrina de Cowas Hirundo fulva T U E 

Red-legged thrush Zorzal de Patas Coloradas 'Iknlus plumbeus R C E,Plant,T,(C) 

pearly-eyed thrasher . Zorzal Pardo Margamps fuscatus R C Plant,T,C,P,D 

Black-whiskered vireo Julib Chivl Vireo altilopuus R C E,Plant,T,(C) 

Golden-winged warbler Reinita Alidorada Vermivora chrysoptera T R T,(C) 

Northern parula Reinita Pechidorada Parula americana T C E,Plant,T,C,P,D 

Magnolia warbler Reinita Manchada Dendmica rnagndia T U Plant,z,C 

Cape May warbler Reinita Tigre D. tigrina T u Plant,T,C 

Black-throated blue warbler Reinita Azul D. c~rulescens T C Plant,T,C PD 

Elfin Woods warbler? Reinita de Bosque Enano D. angelae R U C,P,D- -' ' 

Black-and-white warbler Reinita Trepadora Mniotilta vah T U Plant,T,C,P,D 

American redstart Candelita Setophaga ruticilla T C Plant,T,C,P,D 

Ovenbird Pizpita Dorada Seiurus aurocapillus T U Plant,T,C 

Louisiana waterthrush Pizpita de Rlo S. matacilla T c -- T,C, P,lRI 

Bananaquit Reinita Comun Coereba hln R C Plant,T,C,P,D 

Antillean euphonia Canario del Pais Euphonia musica R C T,C,P,D 

Stripe-headed tanager Reina Mora Spindalis zenn R C Plant,T,C,P,D 

Puerto Rican tanagert Llorosa Nesospingus speculiferus R c (T),c,P,E 

Black-faced grassquit Gorri6n Negro Tiaris bicolor R U (Pht),E 

Puerto Rican bullfinch* Come Name de Puerto Rico Lcaigil2a portoricens~s R C Plant,T,C,P,D 

* = Endemic Subspecies. 

t = Endemic Species. 

*LEF = Luquillo Experimental Forest; status: R = resident, T = transient or migratory. 

sOccurrence in national forest: C = common; U = uncommon; R = rare. 

**Habitat preference: plant = plantation; E = edge of forest at interface with pastures, crop land or fallow land; T = Tsbonuco Forest; C = 

Colorado Forest; P = Palm Forest; D = Dwarf Forest (Elfin Woodland); R = River edge; brackets 1 I denote specific habitat used within a forest 

zone; parentheses ( ) denote habitat where species is much less common than other areas given; underlined habitat type is area in which species is 

most often found. 

Puerto Rican Parrot Studh. -A notable decline 

in the population of Puerto Rican parrots after the 

mid-1950's led to an intensive investigation of the species and its habitat. The West, Central, and East Fork 

watersheds of the Rio Mameyes, located in the upper 

reaches of the Baiio de Oro, comprise traditional parrot 

habitat. Snyder (1978) disclosed that a lack of good 

nesting sites throughout the colorado forest forced the 

parrots to use inadequate sites, which subsequently led 

to reproductive losses. The Puerto Rican parrot monograph, summarizing nearly 20 years of continual 

observations of their daily habits - territorial and feeding behavior using radio telemetry techniques, selection of nesting sites, egg laying, incubation, and 

fledging, among other topics -was recently published 

(Snyder and others 1987). Observations of the parrot 

and iter habitat continue today. 

FHture studies of the Puerto Rican parrot will 

involve the foraging ecology of breeding and nonbreeding territorial pairs and observations of captively bred 

birds after their release. About 200 trees were identified with potential nesting cavities in the Baiio de Oro 
Parrot research blind and nesting boxes within the Baa de Om Natural Area. 

in the mid-1970's. The impact of Hurricane Hugo on 

parrot habitat in general, and on the availability of 

these tree cavities in particular, will be investigated as 

well. 

Other Bird Species Studies. - Transect studies of 

birds were made along the Pico del Este Road and on 

the Rio de la Mina trail (Kepler and Kepler 1970) at the 

highest and lowest elevations in the Baf~o de Oro. Bird 

diversity in the LEF was considered to be lower than 

that in the dry Guanica Forest in southwestern Puerto 

Rico. 

A new species of Parulidae (Dendroica angelae), 

endemic to Puerto Rico, was reported from the LEF's 

dwarf forest (Kepler and Parkes 1972). The species is 

confined to the LEF's upper forests, including the Bafio 

de Oro, and has also been reported in Maricao Forest in 

western Puerto Rico. This bird's isolated habitat, 

restricted range, and similarity to the black-and-white 

warbler were factors responsible for its late discovery. 

Recommended birding sites for the LEF include the 

Yokahu Tower and the Big nee Trail on the Baiio de 

Oro's western border, the Pico del Este Road along its 

southern highpoints, and the Bisley/Mameyes River 

Valley at the northern base of the Baiio de Oro Wiley 

and Bauer 1985). Additional bird species seen from 

these vantage points as well as by qualified observers 

elsewhere within the Bafio de Oro have been incorporated into the survey list (table 15). 

The pearly-eyed thrasher (Margarops fuscatus) was 

not abundant in the upper LEF prior to 1950 (Snyder 

and Taapken 1978). Presently, the thrasher is common 

in colorado forests where it competes with the parrot 

for nesting sites. Several experiments with nest boxes 

of different depths, designs, and physical locations 

within parrot habitat provided guidelines for mitigating competition between the species. 

One of the study sites for determining the effects of 

ectoparasites on the growth and development of pearlyeyed thrashers was located within the Bafio de Oro (fig. 

2). The reproductive success of the thrashers was 

greatly reduced as a consequence of warble fly (Philornis deceptivus) parasitism, which was heavy as a 

result of an apparent increase in the thrasher's density 

(Arendt 1983, Uhazy and Arendt 1986). Parasitized 

nestlings either died or demonstrated different growth 

patterns depending on the timing of the infestation and 

the extent of parasitic attack (Arendt 1985a). The 

impact of parasitic attacks was less on adults than on 

nestlings (Arendt 1985b). 

Some of the observations on the breeding biology and 

diet of red-tailed hawks (Buteo jamaicensis) were also 

made in the Baiio de Oro (Santana and Bmple 1988). 

Observations on the biology of the sharp-shinned hawk 

(Accipiter striatus) continue today. 

Beginning in September 1989, after the passage of 

Hurricane Hugo, point counts of forest bird species 

were initiated in the Baiio de Om. Fifteen stations 

100 m apart are being used to tally North American 

migrants and determine their population densities and 

fluctuation over time. 

Anoline Lizard Studies. -In the early 1960's, the 

distribution of anoline lizards was studied in the 
vicinity of an 800-m elevation in the LEF (Rand 1964), 

probably just west of the B&o de Oro. 75.pical perch 

heights, perch diameters, and shade conditions were 

recorded for Anolis euermanni, A. gundlachi, and A. 

krugi to determine how differences in structural and 

microclimatic preferences result in spatial separation 

among species. 

Today, the distribution of 'anoline lizards, as well as 

the effects of Hurricane Hugo on anoline lizard communities, are being studied along an elevational gradient from 500 to 1,000 m in the LEF. The 800- and 

900-m sites are situated in the Bafio de Oro. The main 

objectives of the study are to assess the composition, 

density, and diversity of anoline lizards, to determine 

structural niche dimensions for all species, and to measure niche breadth and overlap at each elevational 

level. 

Frog Diversity Study. - Beginning in February 

1989, a 200-m transect has been sampled for frog density and abundance in the vicinity of the southwestern 

boundary of the Bafio de Oro. Regular monitoring for 

the most common species includes sampling for adult 

sizes, presence of juveniles, sex determination, and 

breeding activities, including assessment of egg 

clutches. An attempt will also be made to determine the 

effects of Hurricane Hugo on frog populations. 

Invertebrates 

Earthworn Study. -Monthly samplings of earthworms were initiated in each of the Bdo de Oro's 

forest types in July 1991. The objectives of the project 

are to identify earthworm species and to determine if 

correlations exist between their occurrence and 

environmental factors. Soil pits measuring 25 by 25 cm 

and 40 cm deep are being excavated at designated sites, 

and earthworm samples are being extracted from different depths. At each site, the date (season), altitude, 

and loose litter above the pit are noted along with 

several soil parameters such as depth, humidity, bulk 

density, nutrient status, and organic matter content. 

Studies of Other Organisms. -A free-living flatworm, roundworms, nematodes, and numerous mollusks and arthropods were identified in the survey of 

the Bdo de Om (table 14). Much additional work needs 

to be done with these groups of organisms. 

The nomenclature of the earthworms had not been 

resolved at the time of the University of Puerto Rico 

survey. Moreover, the centipedes found in the Baiio de 

Oro could not be designated to corresponding families, 

genera, or species because only one specimen of each 

was encountered and dissection is required before they 

can be classified to family rank. Insect identification of 

Thysanoptera, Collembola, Orthhoptera, and others 

was also impossible. Study of the insects will take 

considerable time and, undoubtedly, involve many 

investigators. 

Classified Plant and Animal Species 

Several of the plant and animal species recorded in 

the Baiio de Oro have been classified by the U.S. Fish 

and Wildlife Service, the Commonwealth Department 

of Natural Resources, or the Forest Service as rare, 

endangered, threatened, or sensitive. The Federal list 

of threatened and endangered species in Puerto Rico 

(Delgado-Mendoza and others 1990) contains the 

Puerto Rican parrot (Amazona vittata), the Arctic peregrine falcon (Falco peregrinus tundrius), and the 

Puerto Rican boa constrictor (Epicrates inornatus). 

Additional species listed by the Commonwealth Department of Natural Resources as threatened or 

endangered are the sharp-shinned hawk (Accipiter 

striatus vendor) and two species of tree frogs, Ekutherodactylus eneidae and E. karlschmidti (DelgadoMendoza and others 1990). 

Animal species classified as sensitive by the U.S. 

Department of Agriculture, Forest Service (1990), 

include the three aforementioned species listed by the 

Commonwealth as well as the broad-winged hawk 

(Buteo platypterus brunnescens) and the elfin woods 

warbler (Denclroica angelae). Plant species on the sensitive list are: Eugenia eggersii, Laplaceaportoricensis, 

Marliera sintensii, Ternstroemia luquillensis, and 

Xylosma schwaneckeanum. 

FUTURE ACTMTIES 

The Bafio de Oro is unique within the LEF and 

Puerto Rico. As witnessed by the rain forest life zones 

that characterize it, the Bafio de Oro is the wettest 

tract in the LEF, which in turn is the wettest area in 

Puerto Nco. The contiguous tract contains a good representation of all forest types undisturbed by humans, 

albeit recently disturbed by Hurricane Hugo. Continued human modification of forest land elsewhere in 

Puerto Rico may make the Baiio de Oro more valuable 

with the passage of time. 

The ecosystems represented are the products of centuries of evolution. The tract is sufficiently large to 

indefinitely support the flora and most of the fauna 

that it contains under current climatic conditions. Certain large animals such as the parrot, the broadwinged hawk, and the tanager could not persist if this 

area were managed in isolation. However, the entire 

Bafio de Oro is surrounded by the LEF, which has been 

protected for over a century. Deliberate modification, 

such as extensive cutting, removal of plants or animals, 

or pollution of the waters, could have deleterious 

effects. In this respect, the Pico del Este road (Route 

930), which borders the Bafio de Om, represents a 

potential problem. Discarding of refuse or disturbance 

of roadside vegetation could become matters of concern 

as the forest receives more visitors. 
LITERATURE CITED 

The size, undisturbed nature, and diversity of the 

Bario de Oro make it an ideal site for ecological investigations. Soils range from deep alluviums in the narrow 

valleys to shallow, rocky ridges. nYo life zones, four 

major forest types, and the rare Pterocarpus swamp are 

found within the area or bordering it. Numerous tree 

species, epiphytes, ferns, liverworts, and mosses characterize the vegetation. The Puerto Rican parrot, the 

Puerto Rican tanager, the broad-winged hawk, and the 

boa constrictor add to the Baiio de Oro's diversity. 

The Baiio de Oro is accessible from the Pico del Este 

road at highest elevations and from the Bisley Trail and 

the Big Treemio de la Mina trails at lowest elevations. 

The Big Treemio de la Mina trail is particularly scenic, 

offering vistas of numerous waterfalls and exposed 

rock along the river. From the standpoint of educational opportunities, the fauna and flora of the mountains may be viewed more easily from other areas, 

suggesting that the Baiio de Oro should not be used 

intensively for this purpose. Moreover, adequate recreational facilities already exist and will be amplified in 

other parts of the LEF; these areas have vistas and 

attractive watercourses like those of the Baiio de Om. 

The major uses of the Bat50 de Oro, then, should be for 

long-term ecological investigations. 

Many of the intriguing aspects of faunal and floral 

relationships in diverse habitats such as that of the 

LEF cannot be answered without knowledge of past 

events. Only too often, ecological studies are exceedingly limited in this regard. Species compositions, 

structural features, and growth rates of the major forest types in the LEF have altered during the past 40 

years. These changes were attributed to disturbance 

caused by Hurricane San Cipriano in 1932 and subsequent recovery of the forest. Likewise, animal populations dependent on the vegetation have most probably 

changed over time, although supportive information on 

this topic is lacking. Knowledge of floral and faunal 

dynamics, and periodic changes in environmental factors, such as rainfall, erosion rates, nutrient status, 

and others, can be attained only through carefully 

implemented, long-term ecological studies. Such studies take on even greater importance with the most 

recent disturbance of the Baiio de Oro by Hurricane 

Hugo. 

Aguayo, Carlos G. 1966. Una lista de 10s moluscos terrestres y fluviales de Puerto Rico. Misc. Pap. Stahlia 

5. Rio Piedras, PR: Museum of Biology, University 

of Puerto Rico. 16 p. 

Alexopoulos, Constantine J. 1970. Rain forest myxomycetes. In: Odum, Howard T.; Pigeon, Robert F., 

eds. A tropical rain forest. Springfield, VA: U.S. 

Department of Commerce: 21-23. Chapter F-3. 

Alvarez-Lopez, Migdalia. 1990. Ecology of Pterocarpus 

officinalis forested wetlands in Puerto Rico. In: 

Lugo, Ariel E.; Brinson, Mark; Brown, Sandra, eds. 

Ecosystems of the world. 15: Forested wetlands. 

Amsterdam: Elsevier: 251-265. Chapter 10. 

Alvarez Ruiz, Migdalia. 1982. A comparison of the 

structure and ecology of Pterocarpus officinalis 

(Jacq.) forested wetlands in Puerto Rico. Rio 

Piedras, PR: University of Puerto Rico. 96 p. M.S. 

thesis. 

Anthony, H.E. 1925-1926. Mammals of Porto Rico, 

living and extinct. In: Scientific survey of Porto Rico 

and the Virgin Islands. New York: New York Academy of Sciences: 1-238 (part 1,2). Vol. 9. 

Arendt, Wayne J. 1983. The effects of dipteran ectoparasitism on the growth and development of nestlings of the pearly-eyed thrasher (Margarops 

fuscatus) in the Luquillo Mountains, Puerto Rico. 

Columbia, MO: University of Missouri. 125 p. M.S. 

thesis. 

Arendt, Wayne J. 1985a. Philornis ectoparasitism of 

pearly-eyed thrashers. 1: Impact on growth and 

development of nestlings. The Auk. 102: 270-280. 

Arendt, Wayne J. 198513. Philnoris ectoparasitism of 

pearly-eyed thrashers. 2: Effects on adults and 

reproduction. The Auk. 102: 281-292. 

Bannister, Barbara A. 1970. Ecological life cycle of 

Euterpe globosa Gaertn. In: Odum, Howard T.; 

Pigeon, Robert F., eds. A tropical rain forest. Springfield, VA: U.S. Department of Commerce: 299-314. 

Chapter B-18. 

Barber, Harry G. 1939. Insects of Porto Rico and the 

Virgin Islands-Hemiptera-Heteroptera (excepting 

the Miridae and Corixidae). In: Scientific survey of 

Porto Rico and the Virgin Islands. New York: New 

York Academy of Sciences: 263-441 (part 3). Vol. 14. 

Bates, Charles 2. 1929. Efectos dd huracan de 13 de 

septiembre de 1928 en distintos arboles. Revista de 

Agricultura de Puerto Rico. 23: 113-117. 

Baynton, Harold W. 1968. The ecology of an elfin forest 

in Puerto Rico. 2: The microclimate of Pico del 

Oeste. Journal of the Arnold Arboretum. 49: 419- 

430. 

Baynton, Harold W. 1969. The ecology of an elfin forest 

in Puerto Rico. 3: Hilltop and forest influences on 

the microclimate of Pico del Oeste. Journal of the 

Arnold Arboretum. 50: 80-92. 

Beard, J.S. 1944. Climax vegetation in tropical America. Ecology. 25(2): 127-158. 

Beard, J.S. 1949. Natural vegetation of the Windward 

and Leeward Islands. Oxford Forestry Memoirs. 21: 

1-192. 

Beinroth, Friedrich H. 1969. An outline of the gwlogy 

of Puerto Rico. Bull. 213. Mayaguez, PR: University 

of Puerto Rico; Rio Piedras, PR: Agricultural 

Experiment Station. 31 p. 
Benedict, Faye F. 1976. Herbivory rates and leaf properties in four forests in Puerto Rico and Florida. 

Gainesville, FL: University of Florida. 78 p. M.S. 

thesis. 

Biaggi, Virgilio. 1970. Las aves de Puerto Rico. Rio 

Piedras, PR: Editorial Universitaria, Universidad de 

Puerto Rico. 371 p. 

Boccheciamp, Rafael A. 1977. Soil survey of the 

Humacao area of eastern Puerto Rico. Washington, 

DC: U.S. Department of Agriculture, Soil Conservation Service. 103 p. + maps. 

Bond, James. 1971. Birds of the West Indies. London: 

Collins Clear-me Press. 256 p. 

Briscoe, C.B. 1966. Weather in the Luquillo Mountains 

of Puerto Rico. bs. Pap. ITF-3. Rio Piedras, PR 

Institute of %pica1 Forestry. 250 p. 

Briscoe, C.B.; Wadsworth, F.H. 1970. Stand structure 

and yield in the tabonuco forest of Puerto Rico. In: 

Odum, Howard T.; Pigeon, Robert F., eds. A tropical 

rain forest. Springfield, VA: U.S. Department of 

Commerce: 79-90. Chapter B-6. 

Britton, N.L.; Wilson, Percy. 1923-1930a. Botany of 

Porto Rico and the Virgin Islands. In: Scientific survey of Porto Rico and the Virgin Islands. New York: 

New York Academy of Sciences (part 14). 626 p. Vol. 

5. 

Britton, N.L.; Wilson, Percy. 1923-1930b. Botany of 

Porto Rico and the Virgin Islands. In: Scientific survey of Porto Rico and the Virgin Islands. New York: 

New York Academy of Sciences (part 14). 663 p. Vol. 

6. 

Brown, Sandra; Lugo, Ariel E.; Silander, Susan; Liegel, 

Leon. 1983. Research history and opportunities in 

the Luquillo Experimental Forest. Gen. %h. Rep. 

SO-44. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 128 p. 

Burke, Kevin. 1988. Tectonic evolution of the Caribbean. Annual Review of Earth Planetary Science. 16: 

201-230. 

Burns, Russel M.; Honkala, Barbara H., tech. coords. 

1990. Silvics of North America. Hardwoods. Agric. 

Handb. 654. Washington, DC: U.S. Department of 

Agriculture. 877 p. Vol. 2. 

Byer, Michael D.; Weaver, Peter L. 1977. Early secondary succession in the dwarf forest of the Luquillo 

Mountains of Puerto Rico. Biotropica. 9(1): 35-47. 

Calvesbert, Robert J. 1970. Climate of Puerto Rico and 

the U.S. Virgin Islands. Silver Spring, MD: U.S. 

Department of Commerce, Environmental Services 

Administration, Environmental Data Service. 29 p. 

Cardona, Walter A. 1984. El Yunque mineral prospects, 

eastern Puerto Rico. Caribbean Journal of Science. 

ZO(1): 79-87. 

Cornstock, William P. 1944. Insects of Porto Rico and 

the Virgin Islands - Rhopalocera or butterflies. In: 

Scientific survey of Porto Rico and the Virgin 

Islands. New York: New York Academy of Sciences: 

421-622 (part 4). Vol. 12. 

Cook, Melville T.; Gleason, Henry A. 1928. Ecological 

survey of the flora of Porto Rico. Journal of the 

Department of Agriculture of Porto Rico. 12(1/2): 3- 

139 + 75 plates. 

Cox, Dennis P.; Briggs, Reginald P. 1973. Metallogenic 

map of Puerto Rico. Misc. Geol. Inv. Map 1-721. 

Washington, DC: U.S. Geological survey. 6 p. 

Crow, T.R.; Weaver, P.L. 1977. Tree growth in a moist 

tropical forest of Puerto Rico. Res. Pap. ITF-22. Rio 

Piedras, PR: Institute of Tropical Forestry. 17 p. 

Crow, Thomas R. 1980. A rain forest chronicle: a 30- 

year record of change in structure and composition 

at El Verde, Puerto Rico. Biotropica. 12(1): 42-55. 

Crum, H.A.; Steere, W.C. 1957. The mosses of Porto 

Rico and the Virgin Islands. In: Scientific survey of 

Porto Rico and the Virgin Islands. New York: New 

York Academy of Science: 395-597 (part 4). Vol. 7. 

Curren, C.H. 1928. Insects of Porto Rico and the Virgin 

Islands-Diptera or two-winged flies. In: Scientific 

survey of Porto Rico and the Virgin Islands. New 

York: New York Academy of Science: 1-118 (part 4). 

Vol. 11. 

Curtis, R.E., Jr.; Aquino, 2.; Diaz, P.L.; Vachier, R.J. 

1989. Water resources data Puerto Rico and the U.S. 

Virgin Islands: water year 1989. PR-89-1. San Juan, 

PR: U.S. Department of the Interior, Geological Survey. 420 p. 

Danforth, Stuart T. 1931. Puerto Rican ornithological 

records. Journal of the Department of Agriculture of 

Porto Rico. 15(1): 33-106. 

Dansereau, Pierre; Buell, Peter. 1966. Studies on the 

vegetation of Puerto Rico. 1: Description and integration of the plant-communities. 2: Analysis and 

mapping of the Roosevelt Roads area. Spec. Pub. 1. 

Mayaguez, PR: Institute of Caribbean Science, University of Puerto Rico. 287 p. 

Delgado-Mendoza, Suzzette; Campbell, Faith; Edelson, 

David. 1990. Extinction in the enchanted isle: protecting our Puerto Rican species. Washington, DC: 

Natural Resources Defense Council. 63 p. + appendix. 

Dillon, William P.; Edgar, N. Brrence; Scanlon, Kathryn M.; Klitgord, Kim D. 1987-88. Geology of the 

Caribbean. Oceanus. 30(u): 42-52. 

Drewry, George. 1970a. Factors affecting activity of 

rain forest frog populations as measured by electrical recording of sound pressure levels. In: Odum, 

Howard T.; Pigeon, Robert F., eds. A tropical rain 

forest. Springfield, VA: U.S. Department of Commerce: 55-68. Chapter E-4. 

Drewry, George E. 1970b. A list of insects from El 

Verde, Puerto Rico. In: Odum, Howard T.; Pigeon, 

Robert F., eds. A tropical rain forest. Springf~eld, VA: 

U.S. Department of Commerce: 129-150. Chapter 

E-10. 
Duke, James A. 1970. Keys for the identification of 

seedlings of some prominent woody species in eight 

forest types in Puerto Rico. In: Odum, Howard T.; 

Pigeon, Robert F., eds. A tropical rain forest. Springfield, VA: U.S. Department of Commerce: 239-274. 

Chapter B-15. 

Dyrness, C.T.; Franklin, Jerry F.; Maser, Chris [and 

others]. 1975. Research natural area needs in the 

Pacific Northwest: a contribution to land use planning: report on Natural Area needs workshop; 1973 

November 29-December 1; Wemme, OR. Gen. Tech. 

Rep. PNW-38. Portland, OR: U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 231 p. 

Edmisten, Joe. 1970. Some autecological studies of 

Ormosia krugii. In: Odum, Howard T.; Pigeon, 

Robert F., eds. A tropical rain forest. Springfield, VA: 

U.S. Department of Commerce: 291-298. Chapter 

B-17. 

Erdman, Donald S. 1961. Notes on the biology of the 

gobiid fish Sicydium plumeri in Puerto Rico. Bulletin of Marine Science of the Gulf and Caribbean. 

ll(3): 448-456. 

Erdman, Donald S. 1986. The green stream goby, 

Sicydium plumieri, in Puerto Rico. Tropical Fish 

Hobbyist. 34(6): 70-74. 

Estrada Pinto, Alejo. 1970. Phenological studies of 

trees at El Verde. In: Odum, Howard T.; Pigeon, 

Robert F., eds. A tropical rain forest. Springfield, VA: 

U.S. Department of Commerce: 237-269. Chapter 

D-14. 

Ewel, John J.; Whitmore, Jacob L. 1973. The ecological 

life zones of Puerto Rico and the U.S. Virgin Islands. 

Res. Pap. ITF-18. Rio Piedras. PR: Institute of Tropical Forestry. 71 p. 

Federal Committee on Research Natural Areas. 1968. 

A directory of research natural areas on Federal 

lands of the United States of America. Washington, 

DC: Federal Committee on Research Natural Areas. 

129 p. 

Foerster, John W. 1971. The ecology of an elfin forest in 

Puerto Rico. 14: The algae of Pico del Oeste. Journal 

of the Arnold Arboretum. 52(1): 86-109. 

Forbes, W.T.M. 1930. Insects of Porto Rico and the 

Virgin Islands. Heterocera or moths (excepting the 

Noctuidae, Geometridae and Pyralidae). In: Scientific survey of Porto Rico and the Virgin Islands. 

New York: New York Academy of Science: 1-171 

(part 1). Vol. 12. 

Forbes, W.T.M. 1931. Supplementary report on the Heterocera or moths of Porto Rico. Journal of the 

Department of Agriculture of Porto Rico. 15(4): 

339-394. 

Francis, John K. [In press]. Silvics manual for Puerto 

Rico. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment 

Station. In cooperation with: University of Puerto 

Rico, Rio Piedras, PR. 

Frangi, Jorge L.; Lugo, Ariel E. 1985. Ecosystem 

dynamics of a subtropical floodplain forest. Ecological Monographs. 55(3): 351-369. 

Fulford, Margaret; Crandall, Barbara; Stotler, Ray. 

1970. The ecology of an elfin forest in Puerto Rico. 

11: The leafy hepaticae of Pico de Oeste. Journal of 

the Arnold Arboretum. 51: 56-69. 

Fulford, Margaret; Crandall, Barbara; Stotler, Ray. 

1971. The ecology of an elfin forest in Puerto Rico. 

15: A study of the leafy hepatic flora of the Luquillo 

Mountains. Journal of the Arnold Arboretum. 52(3): 

435-458. 

Gates, David M. 1969. The ecology of an elfin forest in 

Puerto Rico. 4: Transpiration rates and temperatures of leaves in cool humid environment. Journal 

of the Arnold Arboretum. 50(1): 93-98. 

Gill, A.M. 1969. The ecology of an elfin forest in Puerto 

Rico. 6: Aerial roots. Journal of the Arnold 

Arboretum. 50(2): 197-209. 

Gleason, H.A.; Cook, Me1 T. 1927. Plant ecology of 

Porto Rico. In: Scientific survey of Porto Rico and 

the Virgin Islands. New York: New York Academy of 

Science: 1-173 (part 1-2) + plates. Vol. 7. 

Gradstein, S.R. 1989. A key to the Hepaticae and 

Anthocerotae of Puerto Rico and the Virgin Islands. 

The Bryologist. 92(3) 329-348. 

Grubb, P.J. 1971. Interpretation of the Massenerhebung effect on tropical mountains. Nature. 229: 

44-45. 

Guariguata, Manuel R. 1990. Landslide disturbance 

and forest regeneration in the upper Luquillo Mountains of Puerto Rico. Journal of Ecology. 78: 814- 

832. 

Harris, Richard C. 1989. Keys to the lichen-forming 

fungi of Puerto Rico: tropical lichen workshop; 1989 

May 21-31; Ponce, PR. New York: New York Botanical Garden; Catholic University of Puerto Rico. 107 

P. 

Holdridge, L.R. 1967. Life zone ecology. San Jose, Costa 

Rica: Tropical Science Center. 206 p. 

Howard, Richard A. 1968. The ecology of an elfin forest 

in Puerto Rico. 1: Introduction and composition 

studies. Journal of the Arnold Arboretum. 49(4): 

382-418. 

Howard, Richard A. 1969. The ecology of an elfin forest 

in Puerto Rico. 8: Studies of stem growth and form 

and of leaf structure. Journal of the Arnold 

Arboretum. 50(2): 225-262. 

Howard, Richard A. 1970a. The ecology of an elfin 

forest in Puerto Rico. 10: Notes on two species of 

Marcgravia. Journal of the Arnold Arboretum. 

51(1): 41-55. 

Howard, Richard A. 1970b. The summit forest of Pico 

del Oeste, Puerto Rico. In: Odum, Howard T.; 

Pigeon, Robert F., eds. A tropical rain forest. Springfield, VA: U.S. Department of Commerce: 325-328. 

Chapter B-20. 
Huffaker, Loren. [In press]. Draft: Soil survey of the 

Caribbean National and Luquillo Experimental Forests. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment 

Station. 88 p. + appendices. 

Kepler, Angela K. 1975. Helechos comunes del bosque 

de Luquillo, Puerto Rico. San Juan, PR: InterArnerican University Press. 128 p. 

Kepler, C.B.; Parkes, K.C. 1972. A new species of warbler (Parulidae) from Puerto Rico. The Auk. 89(1): 

1-18. 

Kepler, Cameron B; Kepler, Angela K. 1970. Preliminary comparison of bird species diversity and density in Luquillo and Guanica Forests. In: Odum, 

Howard T.; Pigeon, Robert H., eds. A tropical rain 

forest. Springfield, VA: U.S. Department of Commerce: 183-191. Chapter E-14. 

Kerfoot, 0. 1968. Mist precipitation on vegetation. Forestry Abstracts. 29: 8-20. 

Klots, Elsie B. 1932. Insects of Puerto Rico and the 

Virgin Islands-Odonata or dragonflies. In: Scientific 

survey of Porto Rico and the Virgin Islands. New 

York: New York Academy of Science: 1-104 (part 1). 

Vol. 14. 

Larsen, Matthew C. 1989. Landslides caused by the 

intense precipitation of Hurricane Hugo, September 

1989, eastern Puerto Rico. Water Resources in 

Puerto Rico and the U.S. Virgin Islands: A Review. 

8(5/6): 8. 

Lebron, Maria L. 1977. An autecological study of Palicourea riparia Bentham (Rubiaceae): an ecologically important species in the recovery of a disturbed 

tropical rain forest in Puerto Rico. Chapel Hill, NC: 

University of North Carolina. 238 p. Ph.D. dissertation. 

Leigh, Egbert G., Jr. 1975. Structure and climate in 

tropical rain forest. Annual Review of Ecology and 

Systematics. 6: 67-86. 

Leopold, N.F. 1963. Checklist of birds of Puerto Rico 

and the Virgin Islands. Bull. 168. Rio Piedras, PR: 

University of Puerto Rico, Agriculturai Experiment 

Station. 119 p. 

Little, Elbrt L., Jr. 1970. Relationships of trees of the 

Luquillo Experimental Forest. In: Odum, Howard 

T.; Pigeon, Robert F., eds. A tropical rain forest. 

Springfield, VA: U.S. Department of Commerce: 47- 

58. Chapter B-3. 

Little, Elbert L., Jr.; Wadsworth, Frank H. 1991 Common trees of Puerto Rico and the Virgin Islands. 

Rev. Agric. Handb. 249. Washington, DC: U.S. 

Department of Agriculture. 548 p. 

Little, Elbert L., Jr.; Woodbury, Roy 0. 1976. &es of 

the Caribbean National Forest, Puerto Rico. Res. 

Pap. ITF-20. Rio Piedras, PR: Institute of 'IYopical 

Forestry. 27 p. 

Little, Elbert L., Jr.; Woodbury, Roy 0.; Wadsworth, 

Frank H. 1974. Trees of Puerto Rico and the Virgin 

Islands. Second volume. Agric. Handb. 449. Washington, DC: U.S. Department of Agriculture. 1,024 

P. 

Longwood, Franklin R. 1961. Puerto Rican woods: 

their machining, seasoning, and related characteristics. Agric. Handb. 205. Washington, DC: U.S. 

Department of Agriculture. 98 p. 

Lugo, Ariel E. 1986. Water and the ecosystems of the 

Luquillo Experimental Forest. Gen. Tech. Rep. 

80-63. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 17 p. 

Lugo, Ariel E. 1987. Biosphere reserves in the Tropics: 

An opportunity for integrating wise use and preservation of biotic resources. In: 4th World Wilderness 

Congress for worldwide conservation; Proceedings of 

the symposium on biosphere reserves; 1987 September 11-18; Estes Park, CO. Atlanta, GA: U.S. Department of the Interior, National Park Service: 53-61. 

Lugo, Ariel E.; Brown, Sandra. 1981. Ecological 

monitoring in the Luquillo Forest Reserve. Ambio. 

lO(2-3): 102-107. 

Lyford, Walter H. 1969. The ecology of an elfin forest in 

Puerto Rico. 7: Soil, root and earthworm relationships. Journal of the Arnold Arboretum. 50(2): 210- 

224. 

Martorell, Luis F. 1945. A survey of the forest insects of 

Puerto Rico. Journal of Agriculture of the University of Puerto Rico. 29(3-4): 69-608. 

Masson, D.G.; Scanlon, K.M. 1991. The neotectonic 

setting of Puerto Rico. Geological Society of America 

Bulletin. 103: 144-154. 

Matos, Israel. 1989. Hurricane Hugo causes major 

damage in Puerto Rico and the U.S. Virgin Islands. 

water Resources in Puerto Rico and the U.S. Virgin 

Islands: A Review. 8(5/6): 1-4. 

McDowell, William H.; Sanchez, Cindy G.; Asbury, 

Clyde E.; Ramos Perez, Carlos R. 1990. Influence of 

sea salt aerosols and long range transport on precipitation chemistry at El Verde, Puerto Rim. Atmospheric Environment. 24A(ll): 2813-2821. 

Medina, E.; Cuevas, E.; Weaver, P.L. 1981. Composicion 

foliar y transpiracion de especies lehosas de Pico del 

Este, Sierra de Luquillo, Puerto Rico. Acta Cientifica Venezolana. 32: 159-165. 

MeyerhoMJ Howard A. 1933. Geology of Puerto Rico. 

Monographs: Physical and biological science. Series 

B, 1. San Juan, PR: University of Puerto Rico. 306 p. 

Miller, Harvey A.; Russell, Keith W. 1975. Key to the 

mosses of Puerto Rico. Florida Scientist. 38(3): 175- 

182. 

Mitchell, Raoul C. 1954. A survey of the geology of 

Puerto Rico. Tech. Pap. 13. Rio Piedras, PR: University of Puerto Rico, Agricultural Experiment Station. 167 p. 

Moir, William H. 1972. Natural areas. Science. 177: 

396-400. 
Mosquera, Menandra; Feheley, JoAnne. 1983. Bibliography of forestry in Puerto Rico. Gen. Tech. Rep. 

SO-44. New Orleans, LA : U. S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 128 p. 

Mufiiz-Melendez, Emma. 1978. Demographic analysis 

of the life history of Inga Vera subspecies Vera. 

Knoxville, TN: University of Tennessee. 46 p. M.S. 

thesis. 

Nevling, Lorin I., Jr. 1969. The ecology of an elfin forest 

in Puerto Rico. 5: Chromosome numbers of some 

flowering plants. Journal of the Arnold Arboretum. 

50(1): 99-103. 

Nevling, Lorin I., Jr. 1970. The ecology of an elfin forest 

in Puerto Rico. 12: A new species of Gonocalyx 

(Ericaceae). Journal of the Arnold Arboretum. 51(2): 

221-227. 

Nevling, Lorin I., Jr. 1971. The ecology of an elfin forest 

in Puerto Rico. 16: The flowering cycle and an interpretation of its seasonality. Journal of the Arnold 

Arboretum. 52(4): 586-613. 

Nieves, Luis 0. 1979. Ecological life history study of 

Didympanax morototoni. Rio Piedras, PR: Department of Biology, University of Puerto Rico. 85 p. 

M.S. thesis. 

Nufiez Melendez, Esteban. 1982. Plantas medicinales 

de Puerto Rico. Rio Piedras. PR: Editorial de la 

Universidad de Puerto Rico. 498 p. 

Odum, H.T. 1968. Work circuits and systems stress. In: 

Young, H.E ., ed. Primary productivity and mineral 

cycling in natural ecosystems. Orono, ME: University of Maine Press: 81-138. 

Odum, Howard T. 1970. Rain forest structure and 

mineral-cycling homeostasis. In: Odum, Howard T.; 

Pigeon, Robert F., eds. A tropical rain forest. Springfield, VA: U.S. Department of Commerce: 1-52. 

Chapter H-1. 

Odum, Howard T.; Drewry, George; Kline, J.R. 1970. 

Climate at El Verde, 1963-1966. In: Odum, Howard 

T.; Pigeon, Robert F., eds. A tropical rain forest. 

Springfield, VA: U.S. Department of Commerce: 

347-481. Chapter B-22. 

Odum, Howard T.; Pigeon, Robert F., eds. 1970. A tropical rain forest. Springfield, VA: U.S. Department of 

Commerce. [Number of pages unknown]. 

Odum, Howard T.; Ruiz-Reyes, J. 1970. Holes in leaves 

and the grazing control mechanism. In: Odum, 

Howard T.; Pigeon, Robert I?., eds. A tropical rain 

forest. Springfield, VA: U.S. Department of Commerce: 69-80. Chapter 1-6. 

Osborn, Herbert. 1935. Insects of Porto Rico and the 

Virgin Islands-Homoptera (exclusive of Sternorhynch). In: Scientific survey of Porto Rico and 

the Virgin Islands. New York: New York Academy of 

Science: 111-260 (part 2). Vol. 14. 

Ovington, J.D.; Olson, J.S. 1970. Biomass and chemical 

content of El Verde lower montane rain forest plants. 

In: Odum, Howard T.; Pigeon, Robert F., eds. A 

tropical rain forest. Sprin&eld, VA: U.S. Department of Commerce: 53-77. Chapter H-2. 

Persinos, G.J.; Christie, S.K.; Bidinger, J.M.; Lapiana, 

M.J. 1970. The ecology of an elfin forest in Puerto 

Rico. 13: Phytochemical screening and literature 

survey. Journal of the Arnold Arboretum. 51(4): 

540-546. 

Petrunkevitch, Alexander. 1929. The spiders of Porto 

Rico- part 1. Transactions of the Connecticut Academy of Arts and Science. 30: 1-355. 

Petrunkevitch, Alexander. 1930. The spiders of Porto 

Rico - part 2. Transactions of the Connecticut Academy of Arts and Science. 30: 1-199. 

Proctor, George R. 1989. Ferns of Puerto Rico and the 

Virgin Islands. Memoirs of the New York Botanical 

Garden. 53: 1-389. 

Proctor, George R. 1991. Puerto Rican plant species of 

special concern: status and recommendations. Publ. 

Cientifica Misc. 2. San Juan, PR: Departmento de 

Recursos Naturales. 196 p. 

Raffaele, Herbert A. 1983. A guide to the birds of 

Puerto Rico and the Virgin Islands. San Juan, PR: 

Fondo Educative Interarnerica. 255 p. 

Raffaele, Herbert A.; Velez, Manuel J.; Cotte, Ricardo 

[and others]. 1977. Animales raros y en peligro de 

extincion en Puerto Rico. San Juan, PR: Departamento de Recursos Naturales de Puerto Rico; Servicio de Conservacion de Suelos de 10s Estados 

Unidos. 68 p. 

Rand, A. Stanley. 1964. Ecological distribution in 

anoline lizards of Puerto Rico. Ecology. 45(4): 745- 

752. 

Reagan, Douglas P.; Garrison, Rosser W.; Martinez, 

Jose E. [and others]. 1982. Tropical rain forest 

cycling and transport program: phase 1 report. San 

Juan, PR: Center for Energy and Environment 

Research and University of Puerto Rico. 183 p. 

Rivero, Juan A. 1978. Los anfibios y reptiles de Puerto 

Rico. Mayaguez, PR: Editorial Universitaria, Universidad de Puerto Rico. 148 p. 

Rodriguez-Vidal, Jose A. 1959. Puerto Rican parrot 

(Amazona vittata vittata) study. Monogr. 1. San 

Juan, PR: Commonwealth of Puerto Rico Department of Agriculture and Commerce. 15 p. 

Russell, Keith W.; Miller, H.A. 1977. The ecology of an 

elfin forest in Puerto Rico. 17: Epiphytic mossy vegetation of Pico del Oeste. Journal of the Arnold 

Arboretum. 58(1): 2-24. 

Salivia, Luis A. 1972. Historia de 10s temporales de 

Puerto Rico y las Antillas, 1492 a 1970. Rio Piedras, 

PR: Editorial Edil, Inc., Universidad de Puerto Rico. 

385 p. 

Santana, Eduardo C.; Temple, Stanley A. 1988. Breeding biology and diet of red-tailed hawks in Puerto 

Rico. Biotropica. 20(2): 151-160. 

Sastre de Jesus, Ines. 1979. Ecological life cycle of 
Buchenauia capitata Cvahl.) Eichl., a late secondary 

successional species in the rain forest of Puerto 

Rico. Knoxville, TN: University of Tennessee. 45 p. 

M.S. thesis. 

Scatena, Frederick N. 1989. An introduction to the 

physiography and history of the Bisley Experimental 

Watersheds in the Luquillo Mountains of Puerto 

Rico. Gen. Tech. Rep. SO-72. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, Southern Forest Experiment Station. 22 p. 

Schauss, William. 1940. Insects of Porto Rico and the 

Virgin Islands-Moths. In: Scientific survey of Porto 

Rico and the Virgin Islands. New York: New York 

Academy of Science: 177-417 (parts 2, 3). Vol. 12. 

Schmidt, Karl P. 1928. Amphibians and land reptiles of 

Porto Rico, with a list of those reported from the 

Virgin Islands. In: Scientific survey of Porto Rico 

and the Virgin Islands. New York: New York Academy of Science: 1-160 (Part 1). Vol. 10. 

Seaver, Fred J.; Chardon, Carlos E. 1926. Mycology. In: 

Scientific survey of Porto Rico and the Virgin 

Islands. New York: New York Academy of Science: 

1-208 (part 2). Vol. 8. 

Seaver, Fred J.; Chardon, Carlos E.; Toro, Rafael A.; 

Kern, Frank D. 1926. Supplement to mycology. In: 

Scientific survey of Porto Rico and the Virgin 

Islands. New York: New York Academy of Science: 

209-311 (part 2). Vol. 8. 

Seiders, Victor M. 1971a. Cretaceous and lower tertiary 

stratigraphy of the Gurabo and El Yunque quadrangles, Puerto Rico. Bull. 1294-F. Washington, DC: 

U.S. Department of the Interior, Geological Survey. 

58 p. + maps. 

Seiders, Victor M. 1971b. Geologic map of the El Yunque quadrangle, Puerto Rico. Misc. Geol. Inv. Map 

1-658. Washington, DC : U.S. Department of the 

Interior, Geologic Survey. 

Silander, Susan R. 1979. A study of the ecological life 

history of Cecropia peltata L., an early secondary 

successional species in the rain forest of Puerto 

Rico. Knoxville, TN: University of Tennessee. 94 p. 

M.S. thesis. 

Smith, M.R. 1936. The ants of Puerto Rico. The Journal of Agriculture of the University of Puerto Rico. 

20(4): 819-875. 

Smith, Robert F. 1970. Preliminary illustrated leaf key 

to the woody plants of the Luquillo Mountains. In: 

Odum, Howard T.; Pigeon, Robert F., eds. A tropical 

rain forest. Springfield, VA: U.S. Department of 

Commerce: 275-290. Chapter B-16. 

Snyder, Noel F.R. 1978. Puerto Rican parrots and nestsite scarcity. In: Temple, Stanley A., ed. Endangered 

birds: management techniques for preserving 

threatened birds. Madison, WI: University of 

Wisconsin Press: 47-53. 

Snyder, Noel F.R.; Taapken, John D. 1978. Puerto 

Rican parrots and nest predation by pearly-eyed 

thrashers. In: Temple, Stanley A., ed. Endangered 

birds: management techniques for preserving 

threatened birds. Madison, WI: University of 

Wisconsin Press: 113-120. 

Snyder, Noel F.R.; Wiley, James W.; Kepler, Cameron B. 

1987. The parrots of Luquillo: natural history and 

conservation of the Puerto Rican parrot. Los 

Angeles: Western Foundation of Vertebrate Zoology. 

384 p. 

Starrett, Andrew. 1962. The bats of Puerto Rico and 

the Virgin Islands with a check list and keys for 

identification. Caribbean Journal of Science. 2(1): 

1-7. 

Stehle, Henri. 1945. Forest types of the Caribbean 

Islands-part 1. Caribbean Forester. 6: 273-408. 

Supplement. 

Stejneger, Leonhard. 1904. The herpetology of Porto 

Rico. In: Annual report of the board of regents of the 

Smithsonian Institution. Washington, DC: Smithsonian Institution: 549-721. 

Tamsitt, J.R.; Valdivieso, Dario. 1970. Observations on 

bats and their ectoparasites. In: Odum, Howard T.; 

Pigeon, Robert F., eds. A tropical rain forest. Springfield, VA: U.S. Department of Commerce: 123-128. 

Chapter E-9. 

Thomas, Richard. 1966. Additional cotes on the 

amphisbaenids of greater Puerto Rico. Brevoria. 

249: 1-23. 

Uhazy, Leslie S.; Arendt, Wayne J. 1986. Pathogenesis 

associated with Philornid myiasis (Diptera: Muscidae) on nestling pearly-eyed thrashers (Aves: Mimidae) in the Luquillo Rain Forest, Puerto Rico. 

Journal of Wildlife Diseases. 22(2): 224-237. 

U.S. Department of Commerce. 1970-82. Climatological data: Puerto Rico and Virgin Islands. Asheville, 

NC: National Oceanic and Atmospheric Association, 

National Climate Center. Vols. 16-28. 

U.S. Department of Agriculture, Forest Service. 1990. 

Draft: amended land and resource management 

plan: Caribbean National Forest/Luquillo Experimental Forest. Rio Piedras, PR: U.S. Department of 

Agriculture, Forest Service, Southern bgion and 

Southern Forest Experiment Station. 6 chapters + 

appendices. 

Van der Schalie, Henry. 1948. The land and freshwater 

mollusks of Puerto Rico. Misc. Pub. 70. Ann Arbor, 

MI: Museum of Zoology, University of Michigan. 128 

p. + plates. 

Van Valen, Leigh. 1975. Life, death, and energy of a 

tree. Biotropica. 7(4): 259-269. 

Wadsworth, Frank H. 1948. The climate of the 

Luquillo Mountains and its significance to the people of Puerto Rico. Caribbean Forester. 9: 321-335. 

Wadsworth, Frank H. 1950a. The development of the 

forest land resources of the Luquillo Mountains, 

Puerto Rico. Ann Arbor, MI: University of Michigan. 481 p. Ph.D. dissertation. 
Wadsworth, Frank H. 1950b. Notes on the climax forests of Puerto Rico and their destruction and conservation prior to 1900. Caribbean Forester. 11: 38-47. 

Wadsworth, Frank H. 1951. Forest management in the 

Luquillo Mountains. 1: The setting. Caribbean Forester. 12(3): 93-114. 

Wadsworth, Frank H. 1952. Forest management in the 

Luquillo Mountains. 3: Selection of products and 

silvicultural policies. Caribbean Forester. 13: 93-119. 

Wadsworth, Frank H. 1970. Review of past research in 

the Luquillo Mountains of Puerto Rico. In: Odum, 

Howard T.; Pigeon, Robert F., eds. A tropical rain 

forest. Springfield, VA: U.S. Department of Commerce: 33-46. Chapter B-2. 

Wadsworth, Frank H.; Bonnet, Juan A. 1951. Soil as a 

factor in the occurrence of two types of montane 

forest in Puerto Rico. Caribbean Forester. 12: 67-70. 

Wadsworth, Frank H.; Englerth, George H. 1959. 

Effects of the 1956 hurricane on forests in Puerto 

Rico. Caribbean Forester 20: 38-51. 

Wagner, Richard J.; Wagner, Anstiss B.; Howard, Richard A. 1969. The ecology of an elfin forest in Puerto 

Rico. 9: Chemical studies of colored leaves. Journal 

of the Arnold Arboretum. 50(4): 556-565. 

Walker, Lawrence R.; Brokaw, Nicholas V.; Lodge, D. 

Jean; Waide, Robert B. 1991. Ecosystem, plant, and 

animal responses to hurricanes in the Caribbean. 

Biotropica (special issue). 23(4a): 313-521. 

Walker Layton, Benjamin. 1986. Reproductive chronology and habitat use by black rats (Rattus rattus) in 

Puerto Rican parrot (Amazona vittata) habitat. 

Baton Rouge, LA: Louisiana State University, 

School of Forestry, Wildlife and Fisheries. 98 .p. 

Weathers, Kathleen C.; Likens, Gene E.; Bormann, F. 

Herbert [and others]. 1988. Cloudwater chemistry 

from ten sites in North America. Environmental 

Science & Technology. 22: 1018-1026. 

Weaver, P.L.; Medina, E.; Pool, D. [and others]. 1986. 

Ecological observations in the dwarf cloud forest of 

the Luquillo Mountains. Biotropica. 18: 79-85. 

Weaver, Peter L. 1972a. Cloud moisture interception in 

the Luquillo Mountains of Puerto Rico. Caribbean 

Journal of Science. ll(3-4): 129-144. 

Weaver, Peter L. 1972b. The dwarf forest of Pico del 

Este and the Luquillo Mountains. Revista Interamericana. 2(2): 174-186. 

Weaver, Peter L. 1975. Transpiration rates in the elfin 

forest of the Luquillo Mountains of Puerto Rico. 

Caribbean Journal of Science. 15(1-2): 21-30. 

Weaver, Peter L. 1983. Tree growth and stand changes 

in the subtropical life zones of the Luquillo Mountains of Puerto Rico. Res. Pap. SO-190. New Orleans, 

LA: U.S. Department of Agriculture, Forest Service, 

Southern Forest Experiment Station. 24 p. 

Weaver, Peter L. 1986a. Growth and age of Cyrilla 

racemiflora L. in montane forests of Puerto Rico. 

Interciencia. ll(5): 221-228. 

Weaver, Peter L. 1986b. Hurricane damage and recovery in the montane forests of Puerto Rico. Caribbean Journal of Science. 22(1-2): 53-70. 

Weaver, Peter L. 1989. Forest changes after hurricanes 

in Puerto Rico's Luquillo Mountains. Interciencia. 

14(4): 181-192. 

Weaver, Peter L. 1990. Succession in the elfin woodland 

of the Luquillo Mountains of Puerto Rico. Biotropica. 22(1): 83-89. 

Weaver, Peter L.; Byer, Michael D.; Bruck, David L. 

1973. Transpiration rates in the Luquillo Mountains 

of Puerto Rico. Biotropica. 5(2): 123-133. 

Weaver, Peter L.; Murphy, Peter G. 1990. Forest structure and productivity in Puerto Rico's Luquillo 

Mountains. Biotropica. 22(1): 69-82. 

Wetmore, Alex. 1916. Birds of Porto Rico. Bull. 326. 

Washington, DC: U.S. Department of Agriculture. 

140 p. 

Wetmore, Alexander. 1927. The birds of Porto Rico and 

the Virgin Islands. In: Scientific survey of Porto Rico 

and the Virgin Islands. New York: New York Academy of Science: 245-571 (parts 3,4). Vol. 9. 

White, H.H., Jr. 1963. Variation in stand structure 

correlated with altitude in the Luquillo Mountains. 

Caribbean Forester. 24(1): 46-52. 

Wiley, James W.; Bauer, Gerald P. 1985. Caribbean 

National Forest, Puerto Rico. American Birds. 39(1): 

12-18. 

Willig, Michael R.; Gannon, Michael R. 1991. The effect 

of Hurricane Hugo on bat ecology with emphasis on 

an endemic Puerto Rican bat (Stenoderma rufum) 

in the Luquillo Experimental Forest. Lubbock, TX: 

Texas Technical University, Department of Biological Science; research report. 30 p. 

Wolcott, George N. 1923. Insectae Portoricensis. Journal of Agriculture of Porto Rico. 7(2): 1-312. 

Wolcott, George N. 1936. Insectae Borinquensis. Journal of Agriculture of the University of Puerto Rico. 

20(1): 1-627. 

Wolcott, George N. 1948. The insects of Puerto Rico. 

Journal of Agriculture of the University of Puerto 

Rico. 32:(1): 1-975. 

Woodbury, Roy; Raffaele, Herbert; Fram, Mitchell [and 

others]. 1975. Rare and endangered plants of Puerto 

Rico: a committee report. San Juan, PR: U.S. 

Department of Agriculture, Soil Conservation Service and Commonwealth of Puerto Rico Department 

of Natural Resources. 85 p. 

Zwank, Phillip J.; Walker Layton, Benjamin. 1989. 

Black rats as potential Puerto Rican parrot nest 

predators. Caribbean Journal of Science. 25(1-2): 

13-20. 
Appendix Tkble 1.-Select reference list for flora and fauna in Puerto Rico including the Barb de Om Natural Area 

Topics Soums 

Vegetation 

Forest types Beard 1944, 1949; Dansereau and Buell 1966; Ewe1 and Whitmore 1973; Little and 

others 1974; Little and Wadsworth 1991; Stehle 1945; Wadsworth 1951 

Botany Britton and Wilson 1923-30a, 1923-3Ob; Cook and Gleason 1928; Gleason and Cook 

1927; Howard 1968 

Trees 1 Seedlings Duke 1970, Little 1970, Little and others 1974, Little and Wadsworth 1991, Little and 

Woodbury 1976, Longwood 1961, Smith 1970 

Autecology (trees) Bannister 1970; Burns and Honkala 1990f; Edmisten 1970; Francis, in press*; Frangi 

and Lugo 1985; Lebron 1977; Mufiiz-Melendez 1978; Nieves 1979; Sastre de Jesus 

1979; Silander 1979; Van Valen 1975; Weaver 1986b 

Phenology (trees) Estrada Pinto 1970, Nwling 1971 

Ferns Kepler 1975, Proctor 1989 

Medicinal plants Nunez Melendez 1982 

Bryophytes Crum and Steere 1957; Word and others 1970, 1971; Gradstein 1989; Miller and 

Russel 1975; Russel and Miller 1977 

Mycology Seaver and Chardon 1926, Seaver and others 1926 

Lichens Harris 1989 

Myxomycetes Alexopoulos 1970 

Animals 

Mammals Anthony 1925-26, Starrett 1962, Wsitt and Valdivieso 1970 

Biaggi 1970; Bond 1971; Danforth 1931; Leopold 1963; Raffaele 1983; Wetmore 1916, 

1927; Wiley and Bauer 1985 

AmphibiansIReptiles Drewry 1970a, Rand 1964, Rivero 1978, Schmidt 1928, Stejneger 1904, Thomas 1966 

Insects 

Spiders 

Barber 1939; Comstock 1944; Curren 1928; Drewry 1970b; Forbes 1930,1931; Klots 

1932 

Martorell 1945; Osborn 1935; Petrunkevich 1929, 1930; Schauss 1940; Smith 1936; 

Wolcott 1923,1936,1948 

Mollusks Aguayo 1966, Van der Schalie 1948 

Rare / Sensitive Species Proctor 1991, RafTaele and others 1977, USDA FS 1990, Woodbury and others 1975 

*Contains descriptions of 20 tree species native or introduced to Puerto Rico. 

tContai1-t~ descriptions of 71 tree species to date, many of them introduced to Puerto Rico. 
The United States Department of Agriculture (USDA) prohibits discrimination in its programs on the basis of race, color, national origin, sex, religion, age, 

disability, political beliefs, and marital or familial status. (Not all prohibited bases 

apply to all programs.) Persons with disabilities who require alternative means for 

communication of program information (braille, large print, audiotape, etc.) 

should contact the USDA Office of Communications at (202) 720-5881 (voice) or 

(202) 720-7808 (TDD). 

To file a complaint, write the Secretary of Agriculture, U.S. Department of 

Agriculture, Washington, DC 20250, or call (202) 720-7327 (voice) or (202) 

720-1 127 (TDD). USDA is an equal employment opportunity employer. 
Weaver, Peter L. 1994. Baiio de Oro Natural Area, Luquillo Mountains, 

Puerto Rico. Gen. Tech. Rep. SO-111. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment 

Station. 55 p. 

Past and current research in the Baiio de Oro Natural Area is summarized and used as a basis for further investigation. The current state 

of knowledge regarding the environment is outlined. 

Keywords.. Climate, fauna, flora.