bluuebunny/crossref_metadata_2025 huggingface dataset:
On the abundance and density of terrestrial arthropods in Central Amazonian dryland forests
Authors: Adis Joachim
Published: July 2009

Abundance and density data for terrestrial arthropods from the forest floor, trunk and canopy of primary and secondary dryland forests near Manaus, Brazil are given.
Oligochaetes in fire climax grassland and conifer plantations in Papua New Guinea
Authors: Standen Valerie
Published: July 2009

Earthworm populations in grassland and plantations in the area of Bulolo, Papua New Guinea were compared with populations in nearby undisturbed rain forest. The grasslands had been maintained by burning for many years. ThePinusplantation had been developed on a burned grassland site and theAraucariaplantation on a site which had been cleared of secondary forest.

The grasslands and thePinusplantation supported moderate populations of exotic earthworms includingPontoscolex corethrurus, but no indigenous species. TheAraucariasite supported a native species,Amynthas zebrusonly, which was also found together with two other native species at very low density in rain forest.

Exotic earthworm species widespread throughout the tropics, were present in disturbed soils and formed moderately high density populations in burned grasslands. There was no evidence that they displaced native Megascolecidae in rain forest.
Fish communities of a perturbed stream in Southern Nigeria
Authors: Victor Reginald , Tetteh Jacob Odenkey
Published: July 2009

Fish communities of a fourth order stream impounded by a weir were studied in Southern Nigeria. Fifty-eight species were recorded of which 90% occurred upstream while reservoir and downstream accounted for 48% and 43% respectively. The distribution of some fish families indicated the effects of habitat alterations caused by reservoir and downstream conditions. The fauna upstream was different from that of reservoir and downstream. Relative abundance of non-cichlids common to reservoir and downstream showed 42% similarity. The longitudinal distribution of three non-cichlid populations was different in reservoir and downstream. Non-cichlid species richness was almost similar in reservoir and downstream, but its general diversity and evenness were higher in reservoir than its downstream. Fish community changes in this stream are discussed.
Vegetation damage in an oil field in the Niger Delta of Nigeria
Authors: Fagbami A. A. , Udo E. J. , Odu C. T. I.
Published: July 2009

An investigation into the causes of massive destruction of the vegetation around Tsekelewu Oil Field in the Niger Delta was carried out. The 200 km2 area suffering varying degrees of damage was mapped and the damage quantified by photo interpretation of black and white aerial photographs. Soil, surface and ground water samples were taken from the various zones for chemical analyses which included the determination of pH, electrical conductivity and soluble salt analysis.

The results showed that salt accumulation decreased from the sea inland-wards, with some upsurge in the saline-fresh water transitional zone where the greatest damage occurred. The electrical conductivity of the ground water varied from 45 dS m−1 in the area of greatest damage to less than 4 dS m−1 in the fresh water zone where there was no apparent damage. The salt-tolerant species along the coast were not affected, but in the transitional saline-fresh water zone in which the electrical conductivity of ground water was greater than 30 dS m−1, all the vegetation including the relatively salt-tolerant white mangrove (Avicennia africana) were killed. This destruction is attributed to high salinity caused by salt water incursion from the sea.
Tropical forests: much more than stocks of wood
Authors: Myers Norman
Published: July 2009

Tropical forests offer many more products than the category for which they are best known, viz. wood products. They can supply a host of raw materials, such as resins, oils, fibres and fruits, which collectively represent a commercial value far higher than is generally recognized. In addition they provide an exceptional abundance and variety of genetic resources, which make substantial contributions to modern agriculture, medicine, industry and energy. On top of these materials, tropical forests supply significant environmental benefits, such as protection of the soil and safeguards for watershed systems. While it is sometimes difficult to quantify the economic values of these diverse goods and services, they are often to be reckoned as equal to, if not higher than, the marketplace values represented by the commercial hardwood timber. Yet when the forests are exploited for their hardwood timber, the process is usually so disruptive to forest ecosystems that the other outputs are severely reduced. By contrast, one may exploit the forests for their other outputs with virtually no disruption to forest ecosystems. The paper describes the main categories of non-wood products available from tropical forests, analyses their relative worth, and offers summarized proposals for an expanded approach to forest development in order to take integrative account of the full range of forest benefits.
Simulating forest shade to study the developmental ecology of tropical plants: juvenile growth in three vines in India
Authors: Lee David W.
Published: July 2009

Both light quantity and quality affect the development and autoecology of plants under shade conditions, as in the understorey of tropical forests. However, little research has been directed towards the relative contributions of lowered photosynthetic photon flux density (PPFD) versus altered spectral distributions (as indicated by quantum ratios of 660 to 730 nm, or R:FR) of radiation underneath vegetation canopies. A method for constructing shade enclosures to study the contribution of these two variables is described. Three tropical leguminous vine species (Abrus precatonusL.,Caesalpinia bondicelaFleming andMucuna prunens(L.) DC) were grown in two shade enclosures with 3–4% of solar PPFD with either the R:FR of sunlight (1.10) or foliage shade (0.33), and compared to plants grown in sunlight. Most species treated with low R:FR differed from those treated with high R:FR in (1) percent allocation to dry leaf weight, (2) internode length, (3) dry stem weight/length, (4) specific leaf weight, (5) leaf size, and (6) chlorophyll a/b ratios. However, these plants did not differ in chlorophyll content per leaf dry weight or area. In most cases the effects of low R:FR and PPFD were additional to those of high R:FR and low PPFD. Growth patterns varied among the three species, but both low PPFD and diminished R:FR were important cues in their developmental responses to light environments. This shadehouse system should be useful in studying the effects of light on the developmental ecology of other tropical forest plants.
The post-nuptial moult of Quelea quelea in relation to breeding in Kenya
Authors: Thompson Jeremy John
Published: July 2009

During the unusually extended breeding season of 1984/85 in Tsavo-East National Park, Kenya, Quelea quelea were sampled and moult patterns recorded. Particular attention was paid to individuals with an interrupted moult pattern. These were further classified as either having their moult arrested or suspended. Apparently, post-nuptial moult begins earlier in males than in females. Although the majority of quelea bred and moulted sequentially, these activities overlapped in many individuals and moulting suspended after the replacement of a few feathers. The initiation of post-nuptial moult before the cessation of breeding, followed by moult interruption, is evidence for the physio-ecological drive in quelea to complete their moult as soon as possible to prepare for the next breeding opportunity.
Ecology of the Asian elephant in southern India. I. Movement and habitat utilization patterns
Authors: Sukumar R.
Published: July 2009

The movement and habitat utilization patterns were studied in an Asian elephant population during 1981–83 within a 1130 km2 area in southern India (11° 30′ N to 12° 0′ N and 76° 50′ E to 77° 15′ E). The study area encompasses a diversity of vegetation types from dry thorn forest (250–400 m) through deciduous forest (400–1400 m) to stunted evergreen shola forest and grassland (1400–1800 m).

Home range sizes of some identified elephants were between 105 and 320 km2. Based on the dry season distribution, five different elephant clans, each consisting of between 50 and 200 individuals and having overlapping home ranges, could be defined within the study area. Seasonal habitat preferences were related to the availability of water and the palatability of food plants. During the dry months (January-April) elephants congregated at high densities of up to five individuals km-2 in river valleys where browse plants had a much higher protein content than the coarse tall grasses on hill slopes. With the onset of rains of the first wet season (May-August) they dispersed over a wider area at lower densities, largely into the tall grass forests, to feed on the fresh grasses, which then had a high protein value. During the second wet season (September-December), when the tall grasses became fibrous, they moved into lower elevation short grass open forests.

The normal movement pattern could be upset during years of adverse environmental conditions. However, the movement pattern of elephants in this region has not basically changed for over a century, as inferred from descriptions recorded during the nineteenth century.
Moth diversity of a tropical forest in Peninsular Malaysia
Authors: Barlow H. S. , Woiwod I. P.
Published: July 2009

A standard Rothamsted light trap was operated for slightly over 12 months from the end of September 1979 to October 1980 at Genting Sempah, Pahang in Malaysia. All specimens of macrolepidoptera families together with the Pyralidae were identified, counted and recorded. The numbers of species caught were compared with those obtained by a different method at a nearby site for over 10 years. Diversity, biomass and seasonality of the catch were compared with identically sampled populations in Great Britain and New Zealand. The Genting Sempah trap had very high diversity and biomass compared with the temperate samples and exhibited much less seasonality. The Pyralidae and other families (excluding Noctuidae and Geometridae) formed a much higher component of diversity in Genting than in Britain. The log-normal distribution fits the data better than the log-series. So the inter-quartile slope, Q, is the correct parameter for interfaunal comparisons.
Distribution and ecology of epiphytic bryophytes and lichens in dry evergreen forest of Guyana
Authors: Cornelissen J. H. C. , Steege H. Ter
Published: July 2009

A floristic and ecological study of epiphytic bryophytes and lichens on standing mature Eperua trees was carried out in dry evergreen (walaba) forest in Guyana, South America. The trees were sampled from their base up to the highest canopy twigs, using mountaineering techniques. Clear vertical distribution patterns of epiphytic species and life-forms were found. Many species, particularly foliose lichens, appear to be preferential or exclusive to either Eperua grandiflora or E. falcata (Leguminosae), which are the dominant trees in the walaba forest. Special attention is given to the species-rich epiphyte vegetation on the upper canopy twigs, which include two categories of species: the sun epiphytes and the pioneers (facultative epiphylls).
Estimation of arboreal arthropod density in a dry evergreen forest in Northeastern Thailand
Authors: Watanabe Hiroyuki , Ruaysoongnern Sawaeng
Published: July 2009

The density of arboreal arthropods in a dry evergreen forest in Northeastern Thailand was investigated by the insecticide fogging (knockdown) method. Arthropod densities of 256.4 and 140.4 m-2 were recorded in the dry season and 195.2 and 123.1 m-2 in the rainy season. The main orders were Collembola, Thysanoptera, Hymenoptera (mainly Formicidae) and Hemiptera. Distinct differences were not found in the arthropod faunal structure and density between the dry and rainy seasons. However, this fauna is completely eliminated by the clearing and burning of forest for shifting cultivation.

The results of an experiment investigating the rate of arthropod fall after application of insecticide are presented and problems concerning the efficiency of the estimation methods used in this study are discussed.
A survey of small mammals within a Sabah tree plantation in Malaysia
Authors: Stuebing Robert B. , Gasis Joseph
Published: July 2009

A survey of small mammals was made in a tree plantation in Sabah, East Malaysia. Transects within pure plantings of Eucalyptus deglupta, Gmelina arborea, Albizia falcataria, and A. falcataria/Theobroma cacao were compared with a similar transect laid through seven-year-old logged forest near the plantation. A total of 16 small mammal species were trapped, with 11 found in the logged forest area, and 15 in the plantation. Values for the Shannon-Wiener Diversity Index (H') and for biomass were highest in logged forest, which also showed a low (<45%) Percent Similarity when compared with any of the plantation areas. Highest diversity and biomass values within the plantation were found in Albizia falcataria plantings, while the lowest were found in A. falcataria underplanted with Theobroma cacao. All plantation areas were dominated by Maxomys whiteheads, whereas A. falcataria plantings had the highest numbers of Tupaia glis and Tupaia tana.

The study shows that although tropical plantations of exotic tree species can support a large number of species of scansorial small mammals, overall diversity and species biomass per hectare is much lower than that found in logged forest.
The influence of elephants and fire on a Brachystegia-Julbernardia woodland in Zimbabwe
Authors: Guy Peter R.
Published: July 2009

Brachystegia-Julbernardia (miombo) woodlands inside and outside the Sengwa Wildlife Research Area, Zimbabwe, show major differences in structure, biomass and species composition. The woodlands inside the research area have a lower stem area, tree density and biomass than those outside it. The shrubs inside the research area occur at a higher density than they do outside it, but the biomasses of shrubs in the two woodlands are similar. The woodlands inside the research area are affected by elephants and fire, whereas those outside it are affected mainly by fire. It is postulated that the policy of maintaining the elephant population at 250 in the research area is having a beneficial effect and, provided elephants and fire are kept in check, the woodlands inside the research area will eventually recover.
Litterfall, nutrient-fall and production in an Acacia albida woodland in Zimbabwe
Authors: Dunham Kevin M.
Published: July 2009

Litterfall was recorded for one year in Acacia albida woodland in Mana Pools National Park, Zimbabwe. Leaves fell throughout the year, but leaf-fall rate peaked in the wet season. Litterfall was 1.5 t ha−1 year−1, comprising 50% leaves, 20% fruits, 17% ‘fine’ material (mainly frass), 4% flowers and 9% wood and bark. Net above ground production by A. albida trees was 1.7 t ha−1 year−1, including leaf production of 1.0 t ha−1 year−1, twig production of 0.3 t ha-1 year−1 and fruit production of 0.3 t ha−1 year−1. Insects consumed about 26% of leaf production. Net above ground herbaceous production was estimated from rainfall data using regression equations: it was 6.8 t ha−1 year−1 for annual grasses and 2.8 t ha−1 year−1 for forbs. Net above ground primary production in A. albida woodland was 11.3 t ha−1 year−1. The seasonal variations in the nitrogen, phosphorus, potassium, magnesium and calcium concentrations of different A. albida litter components were recorded. The estimated falls of N, P, K, Ca and Mg were 31.1, 2.1, 9.8, 15.0 and 3.4 kg ha−1 year−1 respectively.
Avian attendance and foraging at army-ant swarms in the tropical rain forest of Los Tuxtlas, Veracruz, Mexico
Authors: Coates-Estrada Rosamond , Estrada Alejandro
Published: July 2009

Foraging and attendance of birds at army-ant swarm raids were studied in the tropical rain forest of Los Tuxtlas, Mexico. Sixty-eight raiding swarms were intercepted over a four-year period of which 57% were Eciton burchelli and 43% Labidus praedator. A total of 461 birds (37 species/12 families) were recorded at swarms of E. burchelli and 208 birds (34 species/10 families) were recorded at L. praedator swarms. The mean number of bird species detected per swarm was 7.2 at E. burchelli raids and 5.6 at L. praedator raids. Red-throated ant-tanagers (Habia fuscicauda) were most frequently seen at the swarms of both army-ant species. Other important species were the golden-crowned warbler (Basileuterus culicivorus), the white-breasted wood wren (Henicorhina leucosticta) and the Kentucky warbler (Oporornis formosus). Swarms of both army-ant species were active year-round. Birds weighing between 20 and 40 g dominated perches closest to the ground and the central zone of the swarms, richest in animal prey. Birds weighing less than 20 g occupied higher perches and tended to forage in more peripheral zones. At Los Tuxtlas raiding swarms of army ants are important in the foraging ecology of 44 bird species, including 12 North American migrants.
Mist and fog interception in elfin cloud forests in Colombia and Venezuela
Authors: Cavelier Jaime , Goldstein Guillermo
Published: July 2009

Fog interception and rainfall were measured during one year in three elfin cloud forests on small mountains along the Caribbean coast of South America and one in the Venezuelan Andes. (1) While rainfall increases from west to east in the small mountains along the coast, fog interception decreases. In 1985, the total annual rainfall and fog interception were 853 mm and 796 mm in the cloud forest of Serrania de Macuira, 1630 mm and 518 mm in Cerro Santa Ana and, 4461 mm and 480 mm in Cerro Copey. In the Andean forest of El Zum-bador, the 1985 rainfall was 1983 mm and the annual fog interception was only 72 mm. (2) Fog interception seems to be an important source of water to the elfin cloud forests of the small mountains which are surrounded by dry vegetation types and where the rainfall regime is highly seasonal. (3) Fog interception increases with altitude (in the same mountain), exposure (windward slopes) and leaf inclination. These variations of fog interception could partially explain the observed distribution of epiphytic flora in some of these cloud forests.
Short term nitrogen dynamics in a small Brazilian wetland (Lago Infernão, São Paulo)
Authors: Howard-Williams Clive , de Esteves F. , Santos J. E. , Downes M. T.
Published: July 2009

We have studied a number of related processes of the nitrogen cycle in a Brazilian floodplain lake to identify the major pools and pathways over a short time period. The study was centred on the littoral zone dominated by the floating plantEichhornia azurea, which has a large epiphyte algal community of which heterocystous cyanobacteria were the major components. The water column was continuously undersaturated with oxygen although some elevated values (to 60% saturation) were recorded in the macrophyte beds in the afternoon. Marked diel temperature changes were documented. NH4-N dominated the dissolved N component in the water with maximal values (60 mg m−3) at lowest O2, concentrations early in the morning. Nitrogen fixation (acetylene reduction) of the epiphyte community showed marked diel changes with daily values of 5 mg N fixed m−2day−1(based on 3:1 C2H4:N2ratio). Macrophyte NH4-N uptake rates (in situincubations) were 93 mg N m−2day−1. The activities of nitrifying bacteria could not be detected with the nitrapyrin block on dark CO2fixation but denitrification (acetylene block technique) was recorded in the sediments when enhanced with NO-3. The major pathways of aquatic nitrogen involved macrophyte uptake and sediment release of NH4-N.
Red crabs in rain forest, Christmas Island: removal and relocation of leaf-fall
Authors: O'Dowd Dennis J. , Lake P. S.
Published: July 2009

Field experiments comparing leaf-fall in the presence and absence of the red land crab, Gecarcoidea natalis, in rain forest on Christmas Island, Indian Ocean showed that, by eating and returning leaves to their burrows, they significantly reduced accumulation of leaf-fall on the forest floor. Red crabs removed 30–50% of the leaf-fall at the experimental sites during the study. Differences in leaf-fall mass between crab-access and exclusion quadrats were positively correlated with the density of foraging red crabs. Red crabs also generated spatial heterogeneity in the distribution of litter on the forest floor by returning litter to their burrows. Leaves lined chambers of 64% of excavated burrows and litter biomass around the entrances was significantly greater than that on off-burrow locations. This was reflected in the significantly higher concentrations of organic matter and nutrients (N, P, K, Ca, Na, and Mg) associated with soils near burrow entrances. These results suggest that a single species, G. natalis, is the major processor of leaf-fall in rain forest on Christmas Island and may affect (1) the temporal and spatial patterns of nutrient availability and (2) the diversity and biomass of the litter fauna.
Fig-eating by birds in a Malaysian lowland rain forest
Authors: Lambert Frank
Published: July 2009

Sixty bird species ate the figs of 29Ficustaxa at a lowland forest site in Peninsular Malaysia. Although most bird-eaten figs were brightly coloured, fourFicusspecies produced dull-coloured ripe fruits. Whilst there was tremendous overlap in the sizes of figs eaten by different bird species, data presented show that the fig resource was partitioned by birds. Large birds were commoner visitors to large-fruitedFicus, but small birds tended to eat small figs. Within two avian genera, theTreronpigeons andMegalaimabarbets, there was distinct partitioning of figs consumed according to fig size.
Metabolism and distribution of grasses in tropical flooded savannas in Venezuela
Authors: Medina Ernesto , Motta Norma
Published: July 2009

Flooded savannas in south-west Venezuela consist of seasonal, marshy and flooded grassland communities, the distribution of which depends on soil level. Seasonal grasslands are dominated by tuft-forming, rhizomatous C4-grasses (exemplified byPaspalum chaffanjoniiin this study), while flooded grasslands are dominated by stoloniferous grasses which develop rooted, floating culms during the rainy season(Leersia hexandraandHymenachne amplexi-caulis).The interface between these two communities is a marshy grassland dominated by stoloniferous grass species which tolerate flooding to a depth of 10 to 25 cm(Panicum laxumandLeersia hexandra).All perennial grass species in flooded grasslands behave as typical C3 plants, while marshy grasslands are dominated byPanicum laxum,a species with reduced photo-respiration, low RuBP/PEP-carboxylase ratios, and low absolute RuBP-carboxylase activity compared to C3 grasses. It also has lower photosynthetic rates than the other grass species.Hymenachne amplexicaulisappears to be the least drought tolerant from the species selected, in accordance with its distribution in the wettest side of the flooding gradient studied. The other species showed marked reduction in relative water content and pronounced increase in leaf proline content in drought experiments lasting 6 to 30 days. Alcohol dehydrogenase increased markedly in response to anaerobiosis in the root environment in the tuft forming grasses, while the stoloniferous species with ascending culms were least affected by this treatment, probably as a result of better aeration inside the culms and also to the production of adventitious roots in upper nodes. Nitrate reductase activity increased as a result of anaerobiosis in the roots but not in the leaves, of all species exceptLeersia hexandra.No difference among the species was found in malate accumulation, or the activity of malic enzyme.
Wetland herpetofauna of Kakadu National Park, Australia: seasonal richness trends, habitat preferences and the effects of feral ungulates
Authors: Friend Gordon R. , Cellier Kevyn M.
Published: July 2009

The abundance and distribution of reptiles and amphibians inhabiting tropical monsoonal wetlands in Kakadu National Park, northern Australia, were monitored between late 1979 and 1982. Seasonal trends in species richness, and the influence of various environmental attributes (including those caused by feral ungulates) on species distribution patterns were also examined.

These wetlands support a high proportion of the amphibian species known from the Park, but are of less importance to reptiles. Within the wetlands, the structurally more complex forested ‘margins’ support many more species than the treeless floodplains. Amphibian species distributions seem to be influenced primarily by elevation, through its effects on soil moisture and flooding levels, while reptile distribution patterns reflect a more complex set of environmental factors, with structural attributes (e.g. vegetation height structure and cover, refuge abundance, leaf litter cover and depth, extent of flooding) being of prime importance.

Feral buffalo and pigs, through their grazing, trampling and wallowing, may considerably influence such structural attributes and change the duration and extent of water lie, and thus indirectly affect species distribution patterns. Current buffalo culling programmes provide an opportunity to monitor vegetation and faunal changes, and quantify feral animal impactpost facto.
Ecology of the small mammals in the riverine forests of the Jubba Valley, Southern Somalia
Authors: Varty Nigel
Published: July 2009

Seven species of rodent, Paraxerus ochraceus, Tatera robusta, Saccostomus meamsi, Praomys (Mastomys) natalensis, Acomys dimidiatus, Thamnomys (Grammomys) dolichurus and Hystrix cristata were recorded in the riverine forests of the Jubba Valley, southern Somalia, in the dry season of 1986. Acomys dimidiatus was the most common of the five species trapped. Overall trap success was low, but increased over successive days. Saccostomus mearnsi, Praomys natalensis, Acomys dimidiatus and Thamnomys dolichurus all showed signs of breeding, and pregnant females of A. dimidiatus and T. dolichurus were trapped until the end of the dry season. Analysis of stomach contents revealed that all five trapped species relied heavily on seeds and, where comparisons could be made, the degree of overlap in diets was high. The findings are discussed in relation to the environmental conditions in the forest and neighbouring habitats.
Responses of ungulates to seasonal inundations in the Amazon floodplain
Authors: Bodmer Richard E.
Published: July 2009

Terrestrial ungulates use different strategies to cope with widespread annual flooding of the Amazon basin. Red brocket deer (Mazama americana) and collared peccary (Tayassu tajacu) retreat to floodplain islands and shift from a frugivorous to a woody browse diet. However, both white-lipped peccary (Tayassu pecari) and lowland tapir (Tapirus terrestris) diets are unaffected by inundations; in the case of white-lipped peccary because they migrate into and out of flooded areas and in the case of lowland tapir because of their semi-aquatic nature. These-strategies of white-lipped peccary and lowland tapir enable them to exploit the greater fruit production of flooded forests more frequently than brocket deer and collared peccary.
Effects of canopy openings on tree seed germination in a Malaysian dipterocarp forest
Authors: Raich James W. , Khoon Gong Wooi
Published: July 2009

The germination of 43 tree species native to the lowland forests of Malaysia was monitored on forest soil in trays placed in closed-canopy forest, an artificial forest gap, and a large clearing. Germination varied significantly among habitats, with only seven species germinating well in all three sites. Seed germination of most species demonstrated clear patterns of shade tolerance or intolerance identical to those long recognized for tree seedlings. Favoured locations for germination were similar to known distributional patterns of adult individuals in mature and secondary forests. Most forest canopy species germinated in the gap, but germination in the large clearing was dramatically reduced or nil; the regeneration of these species in large clearings will be severely retarded even when seeds are present. Canopy-induced inhibition of germination was apparent in several pioneer species; seeds moved from the forest into the gap or clearing germinated rapidly. Results indicate that natural treefall gaps do not inhibit the germination of most species, but do allow pioneer species to germinate, and therefore regenerate. Although germination occurred in all three locations, the level of germination for particular species varied greatly among habitats. We conclude that germination requirements play a very important role in controlling the species composition of regeneration in forest understorey, gap, and large clearing habitats.
Preliminary studies on forest structure and floristics on Volcán Barva, Costa Rica
Authors: Heaney Angela , Proctor John
Published: July 2009

Volcán Barva, Costa Rica, has on its northern slope an unbroken sequence of rain forest on volcanic parent materials from near sea level at La Selva Field Station up to its summit at 2906 m. It provides a good area to study forest changes with altitude and their causes. In the present paper we describe the forests as a background for soil and litterfall studies from 1 ha plots at each of the following altitudes: 100 m, 500 m, 1000 m, 1500 m, 2000 m and 2600 m. The canopy heights (with height of the highest emergent in parentheses) ranged from 35–40 m (45 m) at 100 m to 20–23 m (32 m) at 2600 m; basal area was least (22.7 m2) at 100 m and highest (51.2 m2) at 2600 m; the tree (≥10 cm dbh) density ranged from 391 ha–1at 500 m to 617 ha–1at 2600 m. Most trees were identified and on samples of them we recorded presence of buttresses, lianes, skiophytic climbers, vascular epiphytes and bryophytes; and drew profile diagrams. In the classification of Whitmore (1984) the two lower plots are evergreen lowland rain forests; the other four are lower montane rain forest. Species richness was highest in the plot at 500 m, with at least 135 species of tree, and least at 2600 m, with at least 35 species. The Volcán Barva forest altitudinal sequence is briefly compared with those elsewhere.
Distribution and effects on tree growth of lianas and woody hemiepiphytes in a Costa Rican tropical wet forest
Authors: Clark David B. , Clark Deborah A.
Published: July 2009

We evaluated occurrence and abundance of lianas and woody hemiepiphytes on canopy and emergent tree species in primary tropical wet forest at the La Selva Biological Station, Costa Rica. Two pioneers,Cecropia obtusifoliaandC. insignis, lacked both lianas and hemiepiphytes. The seven non-pioneer species differed significantly in their loads of lianas and hemiepiphytes. For all non-pioneer species, two measures of liana and hemiepiphyte loads (the percentage of the crown occupied and the combined basal area of descending hemiepiphyte and liana roots and stems) increased significantly with tree diameter. In all non-pioneer species, most trees ∵ 70 cm diameter (50–97%) were colonized. Lianas occupied more trees and had a smaller mean host diameter than did hemiepiphytes; however, basal area of descending roots or stems was equivalent for the two life forms in occupied trees. We used partial correlations controlling for tree diameter to evaluate the relationship between annual tree diameter growth and loads of hemiepiphytes and lianas for six non-pioneer species. Five of the six species showed a significant negative correlation between loads and diameter growth. Existing published data show that the high incidence of lianas and hemiepiphytes at La Selva is paralleled in most other Neotropical wet forests.
Reproduction in the toad Colostethus trinitatus (Anura: Dendrobatidae) in a northern Venezuela seasonal environment
Authors: Praderio María José , Robinson Michael D.
Published: July 2009

Various aspects of the reproductive biology of a montane population of Colostethus trinitatus were quantified during the transition from a prolonged dry season to a wet season with abnormally low rainfall. One-third to three-quarters of the females collected in the dry period (March to June) had mature ovarian follicles. The proportion of ovigerous females did not increase in July or August when the number of rainy days was greater. However, breed-ing and egg laying were only observed in the latter season. The principal environmental change that stimulated oviposition was frequent daily rain which increased humidity in the terrestrial nest sites.

Pair formation, nests, and males carrying larvae are reliable criteria that indicate the breeding period of Colostethus trinitatus. The average number of mature ovules (>2 mm) was greater in the wet season (=13.1) than during the dry months (= 11.3). Female standard length and the number of yolked follicles was positively correlated. Five nests contained an average of 13.6 eggs, and males carried only slightly fewer larvae (= 11.5). One female and one individual of unknown sex were found with eggs at two different nests. Five nests were unattended.
Habitat-dependent fruiting behaviour of an understorey tree,Miconia centrodesma, and tropical treefall gaps as keystone habitats for frugivores in Costa Rica
Authors: Levey Douglas J.
Published: July 2009

Fruit production by an understorey tree,Miconia centrodesma, was monitored in treefall gaps and under intact canopy in a Costa Rican lowland rain forest. Trees in gaps displayed much less seasonality in fruit production than trees of intact forest sites. For example, ripe fruits were common on gap trees for a six month period (January-June) when few or no trees under intact canopy were in fruit. The frequent and aseasonal fruiting of gap trees demonstrates that they are not constrained by phenological cueing mechanisms; the influence of such cues is overridden by habitat. Trees in gaps also produced larger crops, had more extended fruiting episodes, and fruited more frequently than shaded conspecifics. This level of intraspecific variation in fruiting behaviour suggests that treefall gaps play an important role in determining the reproductive success ofM. centrodesma. A substantial proportion of an individual's lifetime seed output may be produced during the brief period it occupies a gap. In addition, the large and continuous supply of fruits produced in gaps byM. centrodesmaand other understorey plants, may mean that gaps function as ‘keystone habitats’ by providing resident frugivores with fruit during periods of general fruit scarcity.
Fruit production by Acacia albida trees in Zambezi riverine woodlands
Authors: Dunham Kevin M.
Published: July 2009

Fruit production by Acacia albida (Leguminosae: Mimosoideae) trees in Mana Pools National Park, Zimbabwe, was monitored over eight years. Timing of ripe fruit-fall varied between years, as did fruit production: production of ripe fruits by the same tree varied from 5.4 kg in 1983 to 290.1 kg in 1988. Baboons reduced fruit production by feeding on unripe fruits and the mass eaten each year was negatively correlated with rainfall. Potential fruit production (i.e. production in the absence of baboons) was high when the late wet season was wet or cool and when fruit production in the previous year was low. Late wet season rainfall and temperature probably determined the degree of defoliation by caterpillars: in 1983 and 1987, when the late wet season was hot and dry, the trees were almost completely defoliated. During the late dry season, A. albida fruits were an important component of the diets of waterbuck, eland, elephant, buffalo and kudu; they were seldom eaten by hippopotamus and were ignored by zebra and warthog.
The seedling survivorship and growth of three Shorea species in a Malaysian tropical rain forest
Authors: Turner I. M.
Published: July 2009

There was fruiting of the dipterocarps of Pantai Aceh Forest Reserve, Penang, Peninsular Malaysia in September 1986. The opportunity was taken to investigate the establishment and seedling survival of Shorea curtisii, Shorea multiflora and Shorea pauciflora over the subsequent year. The germination and seedling survival of Shorea curtisii was compared between canopy gaps and forest understorey sites.

Under the shaded conditions none of the species grew beyond the two leaf stage over their first year. Shorea multiflora seedlings suffered a 72% mortality, significantly lower than that of Shorea pauciflora (89%) and Shorea curtisii (93%). The major cause of mortality appeared to be drought, though Shorea curtisii was also prone to predation by small mammals.

In a gap, Shorea curtisii seeds probably germinated less well but seedling survival (28% versus 7%) and growth was better than canopy-shaded conspecifics. Seedlings in gaps escaped small mammal predation.
Nutrient input–output budgets of tropical forest ecosystems: a review
Authors: Bruijnzeel L. A.
Published: July 2009

Atmospheric gains and hydrologic losses of calcium, magnesium, potassium, phosphorus and nitrogen for 25 tropical forest sites on a variety of geological substrates are reviewed. The data set comprised 19 lowland and six montane sites. Twenty studies were subjected to further analysis after initial quality control. These were subdivided into forests on (1) very infertile soils (N = 5), (2) (moderately) infertile soils (N = 5), (3) moderately fertile soils (N = 4) and (4) fertile soils (N = 4). Two studies pertaining to large river basins were treated separately. Although variation in nutrient fluxes was large, reflecting both natural and methodological factors, scatter plots of annual calcium, magnesium and potassium losses v. annual runoff for small catchment areas revealed four groups with characteristic nutrient export patterns that corresponded closely with soil fertility levels. Element losses from the two large basins were much higher than those recorded for small basins in the same areas and were interpreted in terms of depths of weathering front, river incision and root network. Phosphorus accumulated in virtually all cases, reflecting the low mobility of the element. Nitrogen budgets were generally very incomplete. There is a need for more and careful studies of tropical forest nutrient budgets, especially for nitrogen. Standardization of methodology is essential if comparability of results is to be improved.
Interspecific flowering patterns in the Dipterocarpaceae in West Malaysia: implications for predator satiation
Authors: Toy Robin J.
Published: July 2009

Nanophyes shoreae is a pre-dispersal fruit-predator of several species of Dipterocarpaceae. The timing of oviposition of this weevil was monitored in six trees in Pasoh Forest Reserve, West Malaysia from September 1986 to February 1987. A flowering event occurred during this period. Oviposition started within 12 days after peak anthesis, and continued within any one tree for 11–39 days. Host trees of N. shoreae flowered over a 75 day period. Intra-specific flowering synchrony was high but different species flowered sequentially. The behaviour of N. shoreae and the period of the oviposition ‘window’ strongly suggest that this pre-dispersal fruit-predator ‘tracks’ the sequence of flowering shown by its host species. The implications for predator satiation through mass-flowering of the Dipterocarpaceae are discussed.
The effect of water supply on tree seed germination and seedling survival in a tropical seasonal forest in Veracruz, Mexico
Authors: Blain Dominique , Kellman Martin
Published: July 2009

In Iropical seasonal forests, mass seedling death may incidentally occur early in the rainy season following untimely germination provoked by an isolated heavy rainfall. We hypothesized that, in a soil with little moisture retention capacity, irregular rainfall patterns would result in large fluctuations of water supply and, in the early wet season, drought episodes could cause seedling death. This hypothesis was tested in a seasonal tropical forest in Mexico where seedling density is low and the soil consists of almost pure sand with a low water retention capacity. Various patterns of simulated rainfall were applied in the forest to seeds and seedlings of three common tree species. Overall very little difference in germination and seedling survival was observed between the various rainfall treatments. The results showed that rainfall patterns and the soil texture may interact in a much more complex way than was initially hypothesized, and that water availability to seeds and seedlings is not necessarily predictable. The absence of seedlings of the three tree species might be better explained by high seed predation and low light level in the understorey.
Seed selection and removal by ants in a tropical savanna woodland in northern Australia
Authors: Gross C. L. , Whalen M. A. , Andrew M. H.
Published: July 2009

Ant species in the genera Chelaner, Meranoplus and Pheidole were found to be seed-harvesters in a tropical savanna woodland in northern Australia. Despite the availability of other seed types (legume seeds in particular were abundant), all five seed-harvesting species studied are specialists in that they store only grass seeds. Depot experiments, in which seeds were placed along foraging trails, also indicate a preference for grass seeds over legume seeds. At least for some ant species the handling efficiency of legume seeds may be less than that of grass seeds. Marked differences in seed composition of granaries were observed among different seed-harvesting ant species and among colonies of the same species at different sites. All ant species studied, except Pheidole sp. 1, stored only one type of grass seed in granaries at any site despite the availability of other seed types. This contrasts with studies conducted elsewhere in Australia in which generalist foraging by seed-harvesters was found to be common. With the possible exception of Pheidole, dietary specialization docs not appear to arise from a low diversity or abundance of seed supplies. In addition to differences in seed preferences, species of seed-harvesting ants also exhibited some differences in temporal foraging behaviour and some partitioning of resources may be occurring among these co-occurring species. Temporal overlap in foraging, however, was much greater than dietary overlap. The viability of granary seeds was very low for three ant species suggesting that seeds stored by these ants were largely predated rather than dispersed.
The composition of the arthropod fauna of Bornean lowland rain forest trees
Authors: Stork N. E.
Published: July 2009

Data on the laxonomic composition of the arboreal arthropod fauna of 10 Bornean lowland rain forest trees are presented, based on samples obtained using insecticide fogging. Combined samples from all trees comprised 23,874 individuals of at least 3000 species. The mean number of species on each tree was 616.7 with one tree sample containing more than 1007 species. The relative rank of the major orders of arthropods in terms of both species and individuals was remarkably constant across the trees. Hymenoptera, Coleoptera, Diptera and Hemiptcra were the orders with the most species and individuals. Formicidae, though not particularly species rich, was the most abundant family in terms of individuals and the commonest species in six of the 10 trees was an ant. Refogging of one of the trees 10 days after initial sampling showed that the arthropod fauna had not completely recovered. What many arthropods are doing in the canopy is discussed.
Solar energy conversion efficiencies during succession of a tropical rain forest in Amazonia
Authors: Saldarriaga Juan Guillermo , Luxmoore Robert John
Published: July 2009

Mean annual quantities of solar radiation absorbed during various stages of regeneration of a tropical rain forest in the upper Rio Negro valley of Colombia and Venezuela were estimated for the consecutive intervals between clear-cut and 1,3, 10, 20, 35, 60, 80 and 200 years of growth. Forest phytomass and litter fall data from each of these stages were used to calculate the mean annual net dry matter production per unit of absorbed photosynthelically active radiation (PAR), the PAR conversion efficiency. The quantities of PAR absorbed by the forest stands were calculated from the leaf area index values with an extinction coefficient for PAR of 0.74, a PAR albedo of 0.04, and an annual mean incoming PAR of 2.86GJ m-2y-1. Efficiency decreased with increase in successional stage. During the first 10 years of regrowth, the efficiency of conversion of PAR into above-ground phylomass averaged 0.23 g MJ-1, decreasing to 0.07 g MJ-1 over the following 50 years. Inclusion of annual root production in the calculations resulted in a small increase in PAR conversion efficiency; however, efficiency was more than doubled for some periods when the annual leaf and twig lillerfall were included. Efficiency values for above-ground production were much lower than PAR conversion efficiency values estimated for above-ground production of temperate forests.
Feeding strategy and activity budget of the frugivorous batCarollia perspicillata(Chiroptera: Phyllostomidae) in French Guiana
Authors: Charles-Dominique P.
Published: July 2009

The frugivorous phyllostomid batCarollia perspicillatais closely associated with specific fruits which are found and picked in flight, then eaten at a feeding roost. Each fruit eaten corresponds to a single flight. An apparatus designed for this study permits the simultancous tracking of 10 bats equipped with double rhythm transmitters (slow rate corresponding to resting position and rapid rate to flying bouts). (1) The number of flights, (2) the percentage time spent flying and (3) the range of activity were recorded for different categories of animals during two periods of fruit production. Heavier males displayed high activity, while other males, non-breeding females and females in early pregnancy displayed a similar pattern of flying behaviour. Full-term pregnant females and lactating females performed almost as many flying bouts as non-reproductive females, but these flights were much shorter. This unexpected feeding strategy can be interpreted as a means of shifting energy to reproductive effort from exploratory behaviour (non-breeding females performed longer flights which combine the survey of environment and the fruit collection). This strategy, based upon the optimization of flying bouts, is in contrast to those of non-flying mammals and probably is only compatible with periods of high food production.
Population dynamics of earthworms and their activity in forest ecosystems of North-east India
Authors: Bhadauria Tuneera , Ramakrishnan P. S.
Published: July 2009

A comparative analysis of earthworm populations in seral Khasi pine forest represented byPinus kesiya5- and 35-year old stands, and a climax broad-leaved mixed forest represented by a sacred grove was done at altitudes of 1500 m in Meghalaya in north-east India.Tonoscolax horaiioccurred under all forest types whereasAmynthas diffringensandEulyphoeus feslivuswere confined to pine forest stands only.Perionyxsp. andDrawida assamensiswere restricted to the sacred grove.T. horaiihad larger numbers in all three different forest types. This species offers possibilities of vermicullurc for biologically improving soil fertility in manmade ecosystems because of its wide range of tolerance.

Generally earthworm populations were more active during the monsoon season;A. diffringenswas however, more active during the winter, thereby conferring an advantage on this species as it was enabled to avoid competition during the monsoon season when other species dominate. Earthworm activity was generally higher in the sacred grove than in the pine forest stands. Population size was significantly correlated with soil moisture, temperature and pH. Wormcasts had a higher pH and nutrient status than the soil.

In the highly leached soils of the humid tropics where there is a large concentration of fine root biomass in the surface soil layers, earthworm activity is beneficial because it helps incorporate detritus into the mineral soil rapidly and locally concentrates nutrients in the surface layers.