bluuebunny/crossref_metadata_2025 huggingface dataset:
Tree Seed Fate in a Logged and Fragmented Forest Landscape, Northeastern Costa Rica1
Authors: Guariguata Manuel R. , Claire Harold Arias‐Le , Jones Gabriela
Published: March 2006

We compared the seed fate of two animal‐dispersed, large‐seeded timber species (Dipteryx panamensis [Fabaceae] and Carapa guianensis [Meliaceae]) in logged and fragmented forests with that for continuous forest in northeastern Costa Rica. For both species, we quantified rates of seed removal (an index of vertebrate predation) and the fate of dispersed seeds (those carried away from their original location that either germinated or were not subsequently removed within three months). We predicted that (1) fewer seeds would be dispersed by vertebrates in fragmented forest than in continuous forest due to low population abundances after hunting and/or loss of suitable habitat, and (2) seed predation rates would be higher in forest fragments than in continuous forest due to high abundance of small‐bodied seed consumers. We compared three forest fragments currently managed for timber (140–350 ha) and a large reserve of continuous forest (La Selva, 1500 ha and connected to a national park). An exclusion experiment was performed (seeds placed in the open vs. seeds within semipermeable wire cages; 5 cm mesh size) to evaluate the relative roles of large and small animals on seed removal. Seed germination capacity did not differ among all four sites for both species. Removal of Dipteryx seeds was higher in forest fragments (50% removal within 10 days and related to the activity of small rodents) compared to La Selva (50% removal after 50 days). Also, more Dipteryx seeds were dispersed at La Selva than in fragmented forests. Contrary to our predictions, removal of Carapa seeds was equally high among all four sites, and there was a trend for more seeds of Carapa to be dispersed in fragments than in La Selva. Our results suggest that fragmentation effects on tree seed fate may be specific to species in question and contingent on the animal biota involved, and that management strategies for timber production based on regeneration from seed may differ between forest patches and extensive forests.
Flight Speeds, Lipid Reserves, and Predation of the Migratory Neotropical Moth Urania fulgens (Uraniidae)1
Authors: Dudley Robert , Srygley Robert B. , Oliveira Evandro G. , DeVries Phil J.
Published: March 2006

Aerodynamic theory predicts that migrant fliers should reduce their speed of flight as endogenous energy reserves are gradually consumed. This prediction was tested for Urania fulgens (Walker) moths migrating through central Panama in 1987 and again in 1998. Direct airspeed measurements together with chloroform:methanol extractions of abdominal lipids were used to determine that, contrary to theoretical predictions, the speed of flight among individuals was independent of both body mass and abdominal lipid mass.
Habitat Use and Diet of Baird's Tapirs (Tapirus bairdii) in a Montane Cloud Forest of the Cordillera de Talamanca, Costa Rica1
Authors: Tobler Mathias W.
Published: March 2006

Results from 24 transects showed that tapirs were less abundant in areas with higher human presence. They also preferred less steep areas, especially as browsing sites. An analysis of feces showed that fibers were the largest component (40–55%) followed by leaves (10–30%) and twigs (15%). Bamboo (Chusquea spp.) was found in all samples and probably accounts for the high proportion of fibers. Twenty‐seven plant species were identified to be eaten by tapirs.
Seed Dispersal by the Sloth Bear (Melursus ursinus) in South India1
Authors: Sreekumar P. G. , Balakrishnan M.
Published: March 2006

Previous studies have shown that sloth bears are mainly myrmecophagous, but in this study, 39 and 83 percent (wet and dry season, respectively) of scats surveyed in South India contained fruits. Seeds from three of six plant species collected from scats germinated faster than seeds not passing through bears; germination percentage was not higher in any of the six species. These results suggest that the sloth bear may play an important role in the population dynamics of fleshy‐fruited species of the region.
Nutrient Limitation to Primary Productivity in a Secondary Savanna in Venezuela1
Authors: Barger Nichole N. , D'Antonio Carla M. , Ghneim Thaura , Brink Keary , Cuevas Elvira
Published: March 2006

We examined nutrient limitation to primary productivity in a secondary savanna in the interior branch of the Coastal Range of Venezuela, which was converted from forest to savanna more than 100 years ago. We manipulated soil nutrients by adding nitrogen (+N), phosphorus and potassium (+PK), and nitrogen, phosphorus, and potassium (+NPK) to intact savanna. Eleven months after fertilization, we measured aboveground biomass and belowground biomass as live fine roots in the top 20 cm of soil, and species and functional group composition in response to nutrient additions. Aboveground biomass was highest in the NPK treatment ([mean g/m2]; control = 402, +N = 718, +PK = 490, +NPK = 949). Aboveground production, however, appeared to be limited primarily by N. Aboveground biomass increased 78 percent when N was added alone but did not significantly respond to PK additions when compared to controls. In contrast to aboveground biomass, belowground biomass increased with PK additions but showed no significant increase with N (depth 0–20 cm; [mean g/m2]; control = 685, +N = 443, +PK = 827, +NPK = 832). There was also a 36 percent increase in root length with PK additions when compared to controls. Whole savanna shoot:root ratios were similar for control and +PK (0.6), while those for +N or +NPK fertilization were significantly higher (1.7 and 1.2, respectively). Total biomass response (above + belowground) to nutrient additions showed a strong N and PK co‐limitation ([mean g/m2]; control = 1073, +N = 1111, +PK = 1258, +NPK = 1713). Aboveground biomass of all monocots increased with N additions, whereas dicots showed no response to nutrient additions. Trachypogon spp. (T. plumosus+T. vestitus) and Axonopus canescens, the two dominant grasses, made up more than 89 percent of the total aboveground biomass in these sites. Trachypogon spp. responded to NPK, whereas A. canescens, sedges, and the remaining monocots only responded to N. Even though nutrient additions resulted in higher aboveground biomass in N and NPK fertilized plots, this had little effect on plant community composition. With the exception of sedges, which responded positively to N additions and increased from 4 to 8 percent of die plant community, no changes were observed in plant community composition after 11 months.
Elevational Variation of Leaf Traits in Montane Rain Forest Tree Species at La Chinantla, Southern México1
Authors: Velízquez‐Rosas Noé , Meave Jorge , Vízquez‐Santana Sonia
Published: March 2006

Variation in leaf traits of dominant tree species in six montane rain forest communities was analyzed along an elevational gradient ranging from 1220 to 2560 m within a single basin at La Chinantla, Oaxaca, México. Three groups of characters were used: morphological (leaf shape, margin, blade configuration, and phyllotaxy), morphometric (leaf area, leaf mass per area, stomatal density, and blade length/width ratio), and anatomical (thicknesses of blade, palisade [PP], and spongy [SP] parenchymae, PP/SP ratio, and epidermis and cuticle thicknesses). The variation of morphological characteristics was only evident at the highest elevations; in contrast, thickness of leaf blade, PP, SP, as well as leaf mass per area clearly increased along the gradient, whereas leaf area was the only variable that significantly decreased with elevation. Thicknesses of epidermis and of the two cuticles were not significantly correlated with elevation. A classification analysis based on a leaf trait matrix led to the distinction between low and high elevation communities, with an approximate limit between them at ca 2300 to 2400 m. The results are discussed in light of environmental changes occurring along elevational gradients. Leaf characteristics of montane rain forest plants offer important insights about the complex roles of abiotic factors operating in these environments and supplement the traditional physiognomic classification schemes for these communities.
Herbivore‐Free Time? Damage to New Leaves of Woody Plants after Hurricane Andrew1
Authors: Koptur Suzanne , Rodriguez M. Cristina , Oberbauer Steven F. , Weekley Carl , Herndon Alan
Published: March 2006

All broadleaf woody plants of pinelands and hammocks (upland areas) in the northern parts of Everglades National Park were defoliated by the strong winds of Hurricane Andrew in August 1992. Most plants re‐leafed within two months of the storm, at which time we tagged newly produced leaves of eight species (five species in two hardwood hammocks and four in two pineland sites; one species was studied in both habitats), and monitored individual leaf area lost or damaged monthly for three months. We marked a second cohort of new leaves on the same individuals four months later and monitored these for three months. Herbivory rates in leaves of the first cohort were lower than observed in pre‐hurricane studies on two of the species, and lower in the first cohort than in the second cohort in six of the eight species studied, indicating that most insect herbivores were virtually absent for the first few months after the storm. Additionally, most species produced significantly larger leaves in the first cohort than the second cohort, and leaves of the second cohort were not significantly different in size from pre‐hurricane leaves in one species for which pre‐hurricane data were available. The large disturbance of the hurricane defoliated and reduced the above‐ground biomass of the plants, but apparently also eliminated most herbivores and competition for light, facilitating the recovery of the plants.
Spatial and Temporal Variation of Macroinvertebrate Drift in Two Neotropical Streams1
Authors: Boyero Luz , Bosch Jaime
Published: March 2006

The detection of spatial variation in macroinvertebrate drift depends on the spatial scale of investigation in streams of the La Selva Biological Station, Costa Rica. Drift samples were taken in a spatially nested design, with two streams, two reaches per stream, two riffles per reach, and four replicate samples per riffle. Drift showed little variation among streams, but varied significantly at the scales of reach and riffle, with variation among samples also high. In addition, sampling took place at two temporal scales: diel and at two different periods that differed in rainfall conditions. Drift diel periodicity was a clear pattern, while only density of individuals varied among sampling periods. This is the first study of macroinvertebrate drift at multiple spatial scales, despite the recognition that multi‐scale studies are essential for a more complete understanding of community patterns and processes.
Discrimination among Fish Models by Hawaiian Eleotris sandwicensis (Eleotridae)1
Authors: Corkum Lynda D.
Published: March 2006

I examined behavioral responses of the benthic fish Eleotris sandwicensis to painted models (dummies) of fish that Eleotris typically encounter in Hawaii. Eleotris sandwicensis were associated with coarse substrates where their mean (±SE) density was 1.5 (±0.30) fish/m2. I hypothesised that Eleotris would retreat from all models in open areas, but not when they were present in shelters. The five models represented Stenogobius hawaiiensis, Awaous guamensis, E. sandwicensis (female coloration), a male E. sandwicensis in breeding colors (black), and a 12 cm block of wood (control). Whether or not Eleotris held its position or retreated was not a function of body size. Differences among the responses of Eleotris to models depended on whether or not the fish was hidden or exposed on substrates. More retreats in response to models occurred when Eleotris were exposed on substrates than when fish were hidden. There were no significant differences in the response of E. sandwicensis to models when fish were exposed on substrates. In contrast, responses of E. sandwicensis to the models were not random for fish that were hidden, indicating that Eleotris discriminated among the models. The basis for discrimination among models was most likely visual. Although Eleotris are typically secretive, their presence on exposed substrates at this study site may be attributed to die lack of benthivorous fishes and few avian predators. The ability of Eleotris to distinguish among fishes when hidden as well as their tendency to retreat in response to all intruders whenever exposed on substrate surfaces could reduce potential interactions between Eleotris and other native and nonindigenous fishes.
Staggered Flowering in Four Sympatric Varieties of Geonoma cuneata (Palmae)1
Authors: Borchsenius Finn
Published: March 2006

Phenology, flowering biology, and pollination were studied for one year in four sympatric varieties of the polymorphic palm Geonoma cuneata in Ecuador. Flowering seasons of the three most common varieties were significantly staggered resulting in minimal temporal overlap. No marked differences were found with respect to flowering biology or pollination. The implication of these findings for explaining the complicated morphological variation pattern found in G. cuneata and similar species complexes is discussed.
Strategies of Tree Occupation at a Local Scale in terra firme Forests in the Colombian Amazon
Authors: Duque Alvaro , Cavelier Jaime , Posada Alberto
Published: March 2006

The goal of this study was to define differences in species richness and tree and liana species assemblages of three adjacent terra firme forests in the middle Rio Caquetá, Colombia. A vegetation survey of trees and lianas equal to or more than 10 cm diameter at breast height (DBH) was carried out along a single longitudinal transect (10 × 2160 m) passing through a low plain terrace, a high dissected terrace, and a high plain terrace. Species were classified as either locally abundant or locally rare. Abundant species were defined as “generalists” (in all environments), “intermediate” (in two environments), and “specialists” (in only one environment) using a 2 × 3 contingency table. There were 146 (39%) species classified as locally abundant and 231 (61%) as locally rare. Among the abundant species, 70 percent were generalists, 25 percent were specialists, and 5 percent were intermediate. Although there was a significant number of rare species, for those species with sufficient numbers to statistically test spatial distribution, the results suggest that many species are generalists and that beta diversity at the local scale (2.16 ha) is low. Larger data sets over larger geographical areas should be analyzed to determine the degree of species turnover in Amazonian forests.

En el presente estudio, se evaluaron las diferencias en la riqueza de especies y los agrupamientos florísticos de árboles y lianas en tres unidades del paisaje de tierra firme en el río Caquetá, Colombia. Se llevó a cabo un inventario de los árboles y lianas con diámetro a la altura del pecho a 10 cm, a través de un transecto longitudinal (10 × 2160 m) pasando sobre una terraza plana baja, una terraza alta disectada y una terraza alta plana. Las especies fueron clasificadas como localmente abundantes y localmente raras. Las especies abundantes fueron definidas como “generalistas” (en todas las unidades de paisaje), “intermedias” (en dos unidades) y “especialistas” (en unicamente una unidad), usando tablas de contingencia de 2 × 3. En todo, 146 (39%) especies fueron clasificadas como localmente abundantes y 231 (61%) como localmente raras. Entre las especies abundantes, el 70 por ciento fueron generalistas, el 25 por ciento especialistas, y el 5 por ciento intermedias. Aunque hubo un gran número de especies raras, para aquellas especies con abundancia y frecuencia suficiente para que su distribución fuera analizada estadisticamente, los resultados sugieren que muchas especies son generalistas y que la diversidad beta a escala local (2.16 ha) es baja. Bases de datos mucho más grandes son necesarias para determinar el grado de recambio de las especies en los bosques amazónicos.
Red‐rumped Agouti (Dasyprocta leporina) Home Range Use in an Amazonian Forest: Implications for the Aggregated Distribution of Forest Trees
Authors: Silvius Kirsten M. , Fragoso Jose M. V
Published: March 2006

We radio‐tracked five red‐rumped agoutis (Dasyprocta leporina) for two to nine months each at the Estacao Ecologica Ilha de Maraca in the northern Brazilian Amazon. Agoutis fed primarily on seeds and pulp but also ate cotyledons, leaves, flowers, and invertebrates. Three plant species made up 63 percent of the feeding observations. Home range size varied from 3 to 8.5 ha. High‐use areas and home range boundaries shifted from the season of high fruit availability to the season of low fruit availability as different individual trees became the focus of feeding activities. Agoutis foraged preferentially within conspecific patches of preferred fruit species and concentrated their feeding and scatterhoarding activities near individual fruiting trees. These results suggest that agoutis, as extremely short‐distance seed dispersers, may contribute to the aggregated dispersion pattern of large‐seeded tropical forest trees.

Nós seguimos cinco cutias‐vermhelhas (Dasyprocta leporina) marcados com tele‐transmissores por dois á nove mȩses cada um na Estação Ecologica Ilha de Maracá, localizada no no̧rte da Amazonia Brasileira. Os principals itens da dieta foram sementes e polpa de frutos, mas as cutias também consumiram cotiledones, folhas e invertebrados. Trȩs espécies de plantas foram responsáveis por 63 porcento das observanções de dieta. O tamanho da área de vida variou entre 3 e 8.5 ha. As áreas mais usadas e as bordas da área de vida variaram de acordo com as estações de maior e menor disponibilidade de frutos porque diferentes árvores foram procuradas em diferentes estações. As cutias preferiram forragear nas áreas onde as espécies de sementes preferidas eram mais abundantes, e concentraram a alimentação e atividades de armazenamento nas regiões próximas as árvores frutíferas. Estes resultados sugerem que o papel das cutias como dispersores de sementes de curta dista̧ncia podem contribuir para a dispersão agregada de árvores tropicais com sementes grandes.
Remote Sensing Research Priorities in Tropical Dry Forest Environments
Authors: Sánchez‐Azofeifa G. A. , Castro K. L. , Rivard B. , Kalascka M. R. , Harriss R. C.
Published: March 2006

Satellite multi– and hyper‐spectral sensors have evolved over the past three decades into powerful monitoring tools for ecosystem processes. Research in temperate environments, however, has tended to keep pace with new remote sensing technologies more so than in tropical environments. Here, we identify what we consider to be three priority areas for remote sensing research in Neotropical dry forests. The first priority is the use of improved sensor capabilities, which should allow for better characterization of tropical secondary forests than has been achieved. Secondary forests are of key interest due to their potential for sequestering carbon in relatively short periods of time. The second priority is the need to characterize leaf area index (LAI) and other biophysical variables by means of bidirectional reflectance function models. These biophysical parameters have importance linkages with net primary productivity and may be estimated through remote sensing. The third priority is to identify tree species using hyper‐spectral imagery, which represents an entirely new area of research for tropical forests that could have powerful applications in biodiversity conservation.

En las últimas tres decadas, los sensores satelitales multi e hiper‐espectrales han evolucionado hasta convertirse en importantes herramientas para el monitoreo de los ecosistemas. La investigación en los ecosistemas templados y boreales ha seguido el paso de los avances en los sistemas de percepción remota, mientras que en los sistemas tropicales existe un desface significative. En este articulo identificamos y revisamos tres prioridades básicas en la investigación basada en sensores remotos de las regiones neotropicales del bosque seco. Estas prioridades están relacionadas con el monitoreo de bosques secundarios, el desarrollo de estudios relacionados con la cuantificación del área foliar por médio de métodos ópticos y finalmente el desarrollo de técnicas, que ligadas a información hiper‐espectral, puedan ser utilizadas para la identificación de especies de árboles en zonas tropicales. Esta última prioridad representa una nueva área de investigación en los bosques tropicales con importantes connotaciones para la conservación de la biodiversidad boilógica.
Use‐history Effects on Structure and Flora of Caatinga
Authors: Pereira Israel M. , Andrade Leonaldo A. , Sampaio Everardo V. S. B. , Barbosa Maria Regina V.
Published: March 2006

Floristic composition and vegetation structure of plants 3 cm stem diameter or greater were compared at four sites in the Agreste of Paraiba, Brazil: (1) little disturbed for five decades (LD); (2) grazed fragment, selectively logged 16 years before sampling (GF); (3) naturally regrowing for 30 years after 39 years of agriculture (OR); and (4) naturally regrowing for 20 years after 35 years of agriculture plus 15 years of pasture (NR). Cattle graze frequently in the last three sites but very seldom in LD. The little disturbed site had more species (53) than the other three sites (36, 25, and 11 species in GF, OG, and NG, respectively) and also more (3253, 2780, 2780, and 2115 plants/ha) and larger plants (34.8, 26.8, 18.6, and 7.8 m2/ha), including taller tree species (up to 15 m) absent in the other sites (maximum height: 14, 6, and 5 m). Differences were striking in relation to NR, the site with longer use and shorter regrowth period, which was strongly dominated by only two species: Mimosa tenuiflora (73% relative density and 81% basal area) and Piptadenia stipulacea (21% relative density and 16% basal area). These results indicate that abandoned agricultural sites may take several decades to reestablish vegetation similar to die original.

Foram comparadas a composição florística e a estrutura da vegetação das plantas com dia̧metro do caule S 3 cm, em quatro áreas no Agreste da Paraíba: (1) pouco perturbada por cinco décadas (LD); (2) fragmento pastejado que teve corte seletivo de árvores 16 anos antes da amostragem (GF); (3) revegetação natural por 30 anos depois de 39 anos de agricultura (OR); e (4) revegetação natural por 20 anos depois de 35 anos de agricultura e 15 anos como pasto plantado (NR). Gado bovino pasta frequentemente nas trȩs últimas áreas e só raramente em LD. A área pouco perturbada tinha maior número de espécies (53) que as outras trés áreas (36, 25 e 11 espécies em GF, OR e NR, respectivamente), além de plantas em maior número (3253, 2780, 2780 e 2115 plantas/ha) e de maior tamanho (34.8, 26.8, 18.6 e 7.8 m2/ha), incluindo espécies arbóreas mais alias (até 15 m), ausentes nas outras áreas (alturas máximas de 14, 6 e 5 m). As diferenças foram marcantes em relação a NR, área com maior tempo de uso e menor tempo de revegetação, e dominada por apenas duas espécies: Mimosa tenuiflora (densidade e área basal relativas de 73 e 81%) e Piptadenia stipulacea (21% de densidade e 16% de área basal). Os resultados indicam que as áreas de agricultura abandonadas podem levar décadas até estabelecerem vegetação semelhante á original.
Pollinator Assemblages and Visitation Rates for 11 Species of Neotropical Costus (Costaceae)
Authors: Kay Kathleen M. , Schemske Douglas W.
Published: March 2006

Most plant species in tropical forests are pollinated by animals, and yet the diversity and specificity of pollinator assemblages are poorly documented. Here, we investigated pollinator relationships for 11 species of understory herbs in the genus Costus, with the goal of documenting visitation rates and pollinator assemblages among a variety of habitats. For a subset of species, we documented pollinator visitation for multiple years and/or multiple sites to examine temporal and spatial variation in pollinator relationships. Furthermore, we examined the extent to which specialization in pollination systems can contribute to reproductive isolation for sympatric species. Each species was primarily pollinated by either euglossine bees or hummingbirds. Total visitation rates were generally low, averaging 3.2 visits per flower per hour for bee–pollinated species and 0.5 visits per flower per hour for hummingbird–pollinated species. All of the higher elevation species studied were hummingbird–pollinated, while low elevation species were pollinated either by euglossine bees or hummingbirds. Spatial and temporal variation in visitation rates and pollinator identities was minimal. Pollinator specificity was found to contribute strongly to reproductive isolation for the 11 pairwise combinations of sympatric species differing in pollination syndrome, in some cases functioning as a complete barrier to potential pollen flow.

La mayoría de las especies vegetales de los bosques tropicales son polinizadas por animates, pero la diversidad y las especies de los gremios de polinizadores son poco conocidas. En este trabajo investigamos las interacciones de los polinizadores de 11 especies de hierbas del sotobosque pertenecientes al género Costus, con el objetivo de documentar la frecuencia de visitas y los gremios de polinizadores en distintos hábitats. Para un subconjunto de las especies, documentamos las visitas de los polinizadores en varios años y/o sitios para examinar la variación espacial y temporal de las interacciones de los polinizadores. Además, examinamos como la especialización de los sistemas de polinización puede contribuir al aislamiento reproductive de especies simpátricas. Cada especie fue polinizada principalmente ya sea por abejas euglosinas o colibríes. Las frecuencia de visitas fue baja en general, con un promedio de 3.2 visitas/flor/ hora en las especies polinizadas por abejas y 0.5 visitas/flor/hora en las especies polinizadas por colibríes. Las especies localizadas a mayor altitud fueron polinizadas por colibríes, mientras que las de bajas elevaciones fueron polinizadas por ambos. La diferencia espacial y temporal en frecuencia de visitas e identidad de polinizadores fue mínima. Se encontró que la especificidad de los polinizadores contribuye al aislamiento reproductivo, en las 11 combinaciones reciprocas de especies simpátricas se observaron síndromes de polinización diferentes, que en algunos caso sirvieron como una barrera efectiva al flujo potencial de polen.
Foraging Patterns of Sympatric Hornbills during the Nonbreeding Season in Arunachal Pradesh, Northeast India
Authors: Datta Aparajita , Rawat G. S.
Published: March 2006

The diet and food resource partitioning of three sympatric hornbills (Great Hornbill Buceros bicornis, Wreathed Hornbill Aceros undulatus, and Oriental Pied Hornbill Anthracoceros albirostris) during the nonbreeding season were studied relative to fruit availability in a foothill semievergreen forest of Arunachal Pradesh, northeast India. Hornbills fed on fruits of 49 plant species that comprised over 95 percent of their diet. Hornbill species partitioned food resources by varying the relative contribution of figs and non‐fig fruits in the diet. Similarity in non‐fig fruit diet was low. Ten species contributed to over 90 percent of the non‐fig diet. The availability of non‐fig fruits was much lower in the nonbreeding season than in the breeding season; however, despite lower fruit availability during the nonbreeding season, hornbills had a wide diet breadth and indirect evidence suggests that Wreathed Hornbills foraged widely in this season for fruit. Great Hornbills relied more on figs that were available year‐round. The diverse diet breadth that included rare and patchy fruit resources underscores the importance of conserving large forest tracts for hornbills.
Contrasting Responses to Induction Cues by Ants Inhabiting Maieta guianensis (Melastomataceae)
Authors: Lapola David M. , Bruna Emilio M. , Vasconcelos Heraldo L.
Published: March 2006

The two most common ant associates of the understory myrmecophyte Maieta guianensis (Melastomataceae) respond in different ways to experimental cues associated with herbivory. While Pheidole minutula is induced by both physical damage and extracts of leaf tissue, Crematogaster laevis is induced by leaf damage only. We suggest such interspecific variation in induced responses is common and could influence the quality of defense against herbivores provided to host‐plants by ants.

As duas formigas que mais comumente se associam com a mirmecófita de sub‐bosque Maieta guianensis (Melastomataceae) respondem de maneiras diferentes a simulações experimentais de herbivoria. Enquanto Pheidole minutulaé induzida tanto por danos fisicos e extratos de tecido foliar, Crematogaster laevisé induzida apenas pelos danos fisicos. Sugerimos que tal variação interespecifica em respostas induzidas é comum e pode influenciar a qualidade das defesas contra herbívoros que as formigas oferecem às plantas que elas ocupam.
Root/Shoot Allocation and Root Architecture in Seedlings: Variation among Forest Sites, Microhabitats, and Ecological Groups1
Authors: Paz Horacio
Published: March 2006

I analyzed patterns of variation in root mass allocation and root morphology among seedlings of woody species in relation to environmental factors in four Neotropical forests. Among forests, I explored the response of root traits to sites varying in water or nutrient availability. Within each forest, I explored the plastic response of species to different microhabitats: gaps and understory. Additionally, I explored evidence for life history correlation of root and shoot traits by comparing species differing in their successional group (light‐demanding [22 spp.] or shade tolerant [27 spp.]) and germination type (species with photosynthetic cotyledons or species with reserve cotyledons). At each forest site, young seedlings from 10 to 20 species were excavated. A total of 55 species was collected in understory conditions and 31 of them were also collected in gaps. From each seedling, six morphological ratios were determined. Allocation to roots was higher in forest sites with the lowest soil resources. Roots were finer and longer in the most infertile site, while roots were deeper in the site with the longest dry season. Seedling traits did not differ between germination types. Shade tolerant species allocated more to roots and developed thicker roots than light‐demanding species. Light‐demanding species showed stronger plastic responses to habitat than shade tolerant species, and species with photo‐synthetic cotyledons showed lower plasticity than species with reserve cotyledons. Overall, these results suggest that among Neotropical species, root allocation and root morphology of seedlings reflect plant adjustments to water or nutrient availability at geographic and microhabitat scales. In addition, life history specialization to light environments is suggested by differences among groups of species in their allocation to roots and in their root morphology.
Genetic Evidence for Natural Hybridization between Species of Dioecious Ficus on Island Populations1
Authors: Parrish Tracey L. , Koelewijn Hans P. , van Dijk Peter J. , Kruijt Marco
Published: March 2006

Natural hybrids between Ficus septica and two closely related dioecious species, F. fistulosa and F. hispida, were confirmed using amplified fragment length polymorphisms (AFLP) and chloroplast DNA markers. Ficus species have a highly species‐specific pollination mutualism with agaonid wasps. Therefore, the identification of cases in which breakdown in this sophisticated system occurs and the circumstances under which it happens is of interest. Various studies have confirmed that Ficus species are able to hybridize and that pollinator‐specificity breakdown can occur under certain conditions. This study is the first example in which hybrid identity and the presence of hybrids in the natural distribution of parental species for Ficus have been confirmed with molecular markers. Hybrid individuals were identified on three island locations in the Sunda Strait region of Indonesia. These findings support Janzen's (1979) hypothesis that breakdown in pollinator specificity is more likely to occur on islands. We hypothesized that hybrid events could occur when the population size of pollinator wasps was small or had been small in one of the parental species. Later generation hybrids were identified, indicating that backcrossing and introgression did occur to some extent and that therefore, hybrids could be fertile. The small number of hybrids found indicated that there was little effect of hybridization on parental species integrity over the study area. Although hybrid individuals were not common, their presence at multiple sites indicated that the hybridization events reported here were not isolated incidences. Chloroplast DNA haplotypes of hybrids were not derived solely from one species, suggesting that the seed donor was not of the same parental species in all hybridization events.
Does Müllerian Mimicry Work in Nature? Experiments with Butterflies and Birds (Tyrannidae)1
Authors: Pinheiro Carlos E. G.
Published: March 2006

The selective advantage of Müllerian mimicry in nature was investigated by releasing live mimetic and nonmimetic butterflies close to wild, aerial‐hunting tropical kingbirds (Tyrannus melancholicus) and cliff‐flycatchers (Hirundinea ferruginea) in three Amazon habitats (rain forest, a city, and “canga” vegetation). Only mimetic butterflies elicited sight‐rejections by birds, but protection conferred by mimicry was restricted to sites in which both predators and mimics co‐occurred, as in the case of six mimicry rings at a forest site and two at a city site. Most other Müllerian mimics released at city and canga vegetation were heavily attacked and consumed by birds. These results appear to reflect the birds’previous experiences with resident butterfly faunas and illustrate how birds’discriminatory behavior varied among habitats that differed in butterfly species and mimicry ring composition.
Fragmentation and Alteration of Seed Dispersal Processes: An Initial Evaluation of Dung Beetles, Seed Fate, and Seedling Diversity1
Authors: Chapman Colin A. , Chapman Lauren J. , Vulinec Kevina , Zanne Amy , Lawes Michael J.
Published: March 2006

Given current accelerated trends of tropical land conversion, forest fragments are being incorporated into many conservation programs. For investing in fragments to be a viable conservation strategy, forest fragments must maintain their ecological integrity over the long term. Based on fieldwork in 22 forest fragments in the crater lakes region of western Uganda and in the continuous forest of Kibale National Park, we examined (1) seed predation on experimentally dispersed seeds, (2) abundance and composition of the dung beetle community that may play a major role in removing seeds from sites of high seed predation, and (3) compared the fragments’ seedling community composition to adult tree community composition and the seedling community in continuous forest. First, the rate of seed removal at experimental stations was lower in forest fragments (85% remaining after 1 day) than at stations in the continuous forest (79% remaining) and the probability of stations being discovered by seed predators was lower in fragments (23%) than in the intact forest (41%). Second, there was a 62 percent decline in fragment dung beetle abundance. The magnitude of this decline varied among dung beetle guilds that process dung and seeds in different fashions. The abundance of large rollers that move large seeds away from sites of defecation did not differ, but medium and smaller rollers and burying beetles that process small and medium‐sized seeds were less common in the fragments than in the intact forest. Finally, we compared the seedling community composition relative to adult tree community composition by identifying all adult trees in each fragment and by sampling the composition of the seedling community. We found some evidence to suggest that there was movement of seeds among forest fragments by large‐bodied dispersers, particularly chimpanzees (Pan troglodytes) and hornbills (Ceratogymna subcylindricus).
Rapid Turnover and Edge Effects in Dung Beetle Assemblages (Scarabaeidae) at a Bolivian Neotropical Forest‐Savanna Ecotone1
Authors: Spector Sacha , Ayzama Sergio
Published: March 2006

Habitat fragmentation and the widespread creation of habitat edges have recently stimulated interest in assessing the effects of ecotones on biodiversity. Ecotones, natural or anthropogenic, can greatly affect faunal movement, population dynamics, species interactions, and community structure. Few data exist, however, on insect community response to forest–savanna ecotones, a natural analog to anthropogenically cleared areas adjacent to forest. In this study, the abundance, total biomass, average individual biomass, and distribution of scarabaeine dung beetles were examined at a sharp tropical evergreen forest–savanna ecotone in Santa Cruz, Bolivia. The abundance, total biomass, and average individual biomass of dung beetles varied significantly across the forest, edge, and savanna habitats. Species richness (Sobs) also varied significantly across the three habitats, but statistical estimations of true species richness (Sest) did not. Habitat specificity of the dung beetles in this study was extremely high. Of the 50 most common species collected during the study, only 2 species were collected in both the forest and savanna habitats, signaling nearly complete community turnover in just a few meters. Strong edge effects were evidenced by the decline in abundance, total biomass, and species richness at the forest‐savanna boundary.
Roosting Requirements of Two Frugivorous Bats (Sturnira lilium and Arbiteus intermedius) in Fragmented Neotropical Forest1
Authors: Evelyn Michelle J. , Stiles David A.
Published: March 2006

As tropical forest fragmentation accelerates, scientists are concerned with the loss of species, particularly those that play important ecological roles. Because bats play a vital role as the primary seed dispersers in cleared areas, maintaining healthy bat populations is critical to natural forest regeneration. Observations of foraging bats suggest that many Neotropical fruit‐eating species have fairly general habitat requirements and can forage in many different kinds of disturbed vegetation; however, their roosting requirements may be quite different. To test whether or not general foraging requirements are matched by equally broad roosting requirements, we used radiotelemetry to locate roost sites of two common frugivorous bat species (Sturnira lilium and Artibeus intermedius) in a fragmented forest in southeastern Mexico. Sturnira lilium roosted inside tree cavities and selected large‐diameter roost trees in remnant patches of mature forest. Fewer than 2 percent of trees surveyed had a mean diameter equal to or greater than roost trees used by . S. lilium, Artibeus intermedius roosted externally on branches and vines and under palm leaves and selected roost trees of much smaller diameter. Compared to random trees, roost trees chosen by A. intermedius were closer to neighboring taller trees and also closer in height to these trees. Such trees likely provide cryptic roosts beneath multiple overlapping crowns, with sufficient shelter from predators and the elements. While males of A. intermedius generally roosted alone in small trees within secondary forest, females roosted in small groups in larger trees within mature forest and commuted more than three times farther than males to reach their roost sites. Loss of mature forest could impair the ability of frugivorous bats to locate suitable roost sites. This could have a negative impact on bat populations, which in turn could decrease forest regeneration in impacted areas.
Species‐specific Seedling Responses to Hurricane Disturbance in a Puerto Rican Rain Forest1
Authors: Walker Lawrence R. , Lodge D. Jean , Guzmín‐Grajales Sandra M. , Fetcher Ned
Published: March 2006

Seedling dynamics were followed in a Puerto Rican forest for 20 months following a severe hurricane to study the interactive effects of hurricane debris, nutrients, and light on seedling diversity, density, growth, and mortality. Three treatments (debris removal, an unaltered control with hurricane debris, and chemical fertilization added to hurricane debris) altered levels of forest debris and soil nutrients. Canopy openness was measured twice using hemispherical photographs of the canopy. We examined the demographic responses of six common species to treatments over time. Seedling densities increased for all six species but the only significant treatment effects were increased densities of the pioneer treeCecropiaand the shrubPalicoureain the debris removal treatment. Seedling growth declined with declining light levels for four species but not for the pioneer treeAlchorneaor the non‐pioneer treeDacryodes.OnlyCecropiaand the non‐pioneer treeChionanthushad treatment effects on growth. Mortality also differed among species and tended to be highest in the fertilized plots for all butCecropiaandDacryodes.We found only some of the expected differences between pioneer and non‐pioneer plants, as each species had a unique response to the patchy distributions of organic debris, nutrients, and light following the hurricane. High local species diversity was maintained through the individualistic responses of seedlings after a disturbance.
Fruit Bats (Chiroptera: Pteropodidae) as Seed Dispersers and Pollinators in a Lowland Malaysian Rain Forest1
Authors: Hodgkison Robert , Balding Sharon T. , Zubaid Akbar , Kunz Thomas H.
Published: March 2006

The aims of this study were to (1) characterize the food resources exploited by fruit bats (Pteropodidae) within an old‐growth Malaysian dipterocarp forest, (2) test the viability of the seeds they disperse, and (3) provide an estimate of the proportion of trees that are to some degree dependent upon bats for seed dispersal and/or pollination. Fruit species exploited by bats could be distinguished from those eaten by birds largely on the basis of color (as perceived by human beings). Bat‐dispersed fruits were typically inconspicuous shades of green–yellow or dull red–brown, whereas fruits eaten by birds were generally bright orange to red. Dietary overlap between bats and nonflying mammals was relatively high. In contrast to primates and squirrels, which were major seed predators for several of the plant species under investigation, fruit bats had no negative impact on seed viability. A botanical survey in 1 ha of old‐growth forest revealed that 13.7 percent of trees (≫15 cm girth at breast height) were at least partially dependent upon fruit bats for pollination and/or seed dispersal.
Capture Rates of Male Euglossine Bees across a Human Intervention Gradient, Chocó Region, Colombia1
Authors: Otero J. Tupac , Sandino Juan Carlos
Published: March 2006

Euglossine bees are important pollinators of lowland Neotropical forests. Compared to disturbed habitats, undisturbed ones have been previously characterized by higher abundance and diversity of euglossine bees. Most past studies have relied on chemically baiting male bees at single sites within habitats. Over a two‐year period, we employed a repeated‐measures design in which we sampled bees at multiple sites within three different habitat types, reflecting a mosaic of human disturbance (farm, secondary forest, and old logged forest). After 22 monthly samples, a total of 2008 male bees were captured, representing 31 species in five genera: 1156 at the farm (57.6%, 21 spp.), 505 in the secondary forest (25.1%, 27 spp.), and 347 in the old logged forest (17.2%, 21 spp.). Eighty‐one percent of the bees captured belonged to the five most abundant species: Eulaema cingulata, El. chocoana, Euglossa hansoni, Eg. ignita, and Eg. imperialis. These species differed significantly in capture frequencies among habitats. Eulaema cingulata, El. chocoana, and Eg. ignita were captured most frequently at the farm, while Eg. imperialis was most abundant in the secondary forest. In contrast, Eg. hansoni, the sole short‐tongued species among the five, was equally abundant in the two forest habitats but occurred rarely on the farm. Additionally, habitats differed in bee composition. The high capture rates for long‐proboscis species at the farm may have been due to their ability to extract nectar from flowers with long floral tubes, which probably occurred at a greater density on the farmed land than in the adjacent forests.
Influence of Edge Exposure on Tree Seedling Species Recruitment in Tropical Rain Forest Fragments1
Authors: Benitez‐Malvido Julieta , Martínez‐Ramos Miguel
Published: March 2006

Edge creation has a pronounced influence on the understory vegetation, but the effects of edges on seedling species recruitment are still poorly understood. In Central Amazonia, 9–19 years after fragmentation, we recorded species richness and net seedling recruitment rate in 1 ha blocks exposed to none, one, or multiple edges within forest fragments. One‐hectare blocks were located in the center (no edge), the edge (one edge), the corners (two edges) of 10 and 100 ha fragments, and in a 1 ha fragment (four edges). In 1991, we counted all tree seedlings 5–100 cm tall found within permanent 1 m2 plots located within the 1 ha blocks. In May 1993, we manually removed all seedlings that were smaller than 1 m tall from the permanent plots. Six years and five months later (October 1999), all new seedlings recruited into the plots were counted and classified into distinct morphospecies. Species richness of recruited seedlings, scaled by total seedling density, declined from the center to the edge, the corner blocks, and then to the 1 ha fragment. Overall, the four‐edged, 1 ha fragment had the poorest species richness and the non‐edged 100 ha central block the highest. The total number of recruited individuals was 40 percent less than that previously present, with the 100 ha corner having the lowest recruitment. Pairwise comparisons showed that species similarity was related to edge number for the 100 and 1 ha fragments. Species rank/abundance curves showed that a subset of species was common in all blocks within the fragments, and that the 100 ha center held more rare species than any other 1 ha block. This study demonstrated that, in a given fragment patch, the number of tree seedling species recruited varied inversely with the number of edges.
Effects of Species, Density, Patch‐type, and Season on Post‐dispersal Seed Predation in a Puerto Rican Pasture1
Authors: Myster Randall W.
Published: March 2006

An experimental study of seed removal of four woody species in an abandoned pasture revealed significant main effects of species, density (higher densities survived more than lower densities), and patch‐type (seeds under shrub patches survived more than in grass patches), but no effects of season. Rates of seed loss decreased with seed size across species. Significant interactions between species and density and between species and patch‐type were also observed.
Expedition to Kubunitu1
Authors: Whitmore T. C.
Published: March 2006

This is a personal account of a 1964 expedition in search of two conifer species on Mts. Sasari and Kubunitu, the two highest peaks on Santa Ysabel in the Solomon Islands. Dacrydium xanthandrum and Dillenia crenata were both discovered in flower and collections were made. The account was recently discovered in Tim Whitmore's files.