bluuebunny/crossref_metadata_2025_split huggingface dataset:
Germinable soil seed bank dynamics during the gap phase of a humid tropical forest in the Western Ghats of Kerala, India
Authors: Chandrashekara U. M. , Ramakrishnan P. S. 
Published: July 2009

ABSTRACTThe present study showed that the density of germinable seeds in the soil of a humid tropical forest ecosystem at Nelliampathy, in the Western Ghats of Kerala in India, fluctuates sharply at different times of the year. There were more germinable seeds in the soil during the monsoon season. Regeneration was activated after canopy gap formation and thus a decline in the soil seed density in 1-year-old gaps was recorded. However, soil seed density increased with gap age. Differences were found between primary, late secondary and early secondary categories of species with respect to their soil seed bank. There were more seeds of primary species in the soil of natural gaps than in selection felled ones, while the seeds of early secondary shrubs and herbs were more in the soil of selection felled gaps than in natural gaps. The soil seed banks of the primary forest species, being transient, are not an important conservation tool for these species.
Light environment, gas exchange, and annual growth of saplings of three species of rain forest trees in Costa Rica
Authors: Oberbauer Steven F. , Clark David B. , Clark Deborah A. , Rich Paul M. , Vega Gerardo 
Published: July 2009

ABSTRACTLight environment, leaf physiological characteristics, and growth were compared for forest-grown saplings of three species of tropical trees with known life histories. Light environment was assessed both by hemispherical canopy photography and a quantitative visual index of crown illumination. Leaf gas exchange characteristics were measured by infrared gas analysis. The species tested includedLecythis ampla, a species tolerant of understorey conditions,Pithecellobium elegans, a species found in relatively bright sites, andSimarouba amara, a fast-growing, light-demanding species.Annual height and diameter growth did not significantly differ between the three species, but highest average rates were found forSimarouba. Likewise, saplings of the three species were found in similar low light environments althoughSimaroubasaplings were found in slightly brighter sites andLecythissaplings were found in the lowest light environments. Despite similar light regimes, the species differed markedly in leaf area and gas exchange. Leaf areas ofLecythissaplings were five and ten-fold greater thanSimaroubaandPithecellobiumsaplings, respectively. Light-saturated leaf photosynthesis and leaf dark respiration rates ofLecythiswere about half those ofSimarouba; rates ofPithecellobiumwere intermediate.Lecythishad the highest leaf photosynthesis at understorey diffuse light levels. Measures of annual growth were positively correlated with estimates of both direct and diffuse light with the strongest correlations between sapling performance and diffuse light.
Effects of tree species heterogeneity on leaf fall in primary and logged dipterocarp forest in the Ulu Segama Forest Reserve, Sabah, Malaysia
Authors: Burghouts T. B. A. , Campbell E. J. F. , Kolderman P. J. 
Published: July 2009

ABSTRACTEffects of tree species heterogeneity on leaf fall were studied in a primary (4 ha) and in a selectively logged forest plot (2.5 ha) in the Ulu Segama Forest Reserve, Sabah, Malaysia, from April 1988 to December 1989. Leaf fall was collected at 30 sampling points in each plot, and identified to species.Dipterocarpaceae, Euphorbiaceae, Lauraceae, Fagaceae and Meliaceae are important tree families in both plots with regard to their contribution to total basal area, tree density and annual leaf fall. The total number of tree species was higher in the primary forest plot (267) than in the logged forest plot (218), although the number of climber species was higher in the logged forest (44) than in the primary forest plot (33). The overlap in species composition between the two forest plots was relatively small (49%) compared with that in family composition (88%).In the primary forest plot, the Dipterocarpaceae contributed 29% of the total basal area and 34% of the annual leaf fall. In the logged forest plot these contributions were much lower, 11% and 15%. The contribution to annual leaf fall made by climbers and pioneer trees was higher in the logged forest plot (34%) than in the primary forest plot (8%).In the primary forest plot, leaf fall was dominated My large emergent and main canopy trees, mainly dipterocarps, and occurred as regular large peaks. In the logged forest leaf fall was dominated by climbers and many, relatively small trees of pioneer species, such as Macaranga hypoleuca, and was more evenly distributed in time.
Seasonal diet of capuchin monkeys (Cebus apella) in a semideciduous forest in south-east Brazil
Authors: Galetti Mauro , Pedroni Fernando 
Published: July 2009

ABSTRACTThe diet of capuchin monkeys, Cebus apella, in a 250 ha semideciduous forest in south-east Brazil was studied for 44 consecutive months. Based on 367 feeding bouts the diet of capuchins was 53.9% fruit pulp, 16.0% seeds, 11.1% flowers, 6.3% leaves and new shoots, 1.5% roots and 13.9% corn from plantations surrounding the forest. Seventy-one plant species were consumed by capuchins. Food availability was markedly seasonal. During the dry season the fleshy fruit availability decreased, and at that time the capuchins became seed predators and flowereaters. Several fruits eaten by capuchins in the dry season were not consumed by other frugivorous vertebrates, such as howler monkeys, parrots or squirrels, allowing capuchins to avoid competition with other arboreal frugivores. In semideciduous forests where fleshy fruits are less abundant than in the wet forests capuchins are important seed predators.
Vegetation changes following human disturbance of mid-montane forest in the Wau area, Papua New Guinea
Authors: Van Valkenburg Johan L. C. H. , Ketner Pieter 
Published: July 2009

ABSTRACTThis paper examines the floristic changes that occur following human disturbance in mid-montane forest in the Wau area in Papua New Guinea. The study was restricted to a 1600–2400 m altitudinal range on Mt Kaindi, with disturbed forest, and Mt Missim, with undisturbed forest. Special attention was given to the status ofNothofagus pulleiwhich is locally dominant on Mt Kaindi.A major change in floristic composition was observed between 1800 and 2000 m. The abundance and species composition of ferns and mosses above 2000 m characterizes the floristic differences.Nothofagus pulleiwas found to be a pioneer species with a long life-span, one which does not regenerate under its own cover. There were no other important floristic differences betweenNotho-fagus-dominated forest and mixed mid-montane forest.Nothofagus pulleilocally dominates the canopy and thereby suppresses the growth of other trees.
A comparative study of the effects of fluctuations in temperature and moisture supply on hard coat dormancy in seeds of coastal tropical legumes in Mexico
Authors: Moreno-Casasola Patricia , Grime John Philip , Martínez M. Luisa 
Published: July 2009

ABSTRACTThe effect of fluctuations in temperature and moisture supply on hard seeds of nine tropical coastal sand dune legumes, including herbs (Schrankia atiadrivalvis, Macropiilium atropurpureum and Canavalia rosea), and shrubs (Acacia farncsiana, A. macracantha, Mimosa chaetocarpa, Indigoftra sujjruticosa, Crolalaria incana and Chamaecrista chamaecrutoides), has been studied under laboratory and field conditions. Using a fluctuating temperature gradient bar seeds buried in sand were exposed to various amplitudes of diurnal temperature fluctuation over an extended period of time and seed germinability was examined at intervals. Germination percentage increased considerably in most species as a consequence of treatment with marked effects occurring at temperature fluctuations greater than 20°C and becoming detectable after 45 days. In several species the effect of applying wetting and drying cycles was to lower the amplitude of temperature fluctuation necessary to soften the seeds. Species can be grouped into physiological groups on the basis of differences in seed response to temperature fluctuations. It is suggested that these differences may help to explain the mechanisms distinguishing the different colonization patterns observed in tropical sand dune systems.
The distribution of leaf litter invertebrates along a Neotropical altitudinal gradient
Authors: Olson David M. 
Published: July 2009

ABSTRACTLeaf litter invertebrates were sampled at eight sites, approximately 250 m apart in elevation, along an altitudinal transect extending from primary lowland rainforest to cloud forest in western Panama. The study focused on several diverse and numerically important litter invertebrate taxa (e.g., ants, spiders, and beetles) that were effectively sampled using a combination of litter sifting and test tube pitfall traps. The mean altitudinal range of species was around 500 m (standard deviation 370 m) and approximately 50% of the species characteristic of a given elevation dropped out after a 500 m change in elevation in either direction. There was no evidence for distinct altitudinal zonation in leaf litter assemblages. Both species richness and number of individuals of most taxa showed a pronounced decline in the vicinity of the upward transition to cloud forests. The data also suggest a broad mid-elevation peak in sample species richness for the litter invertebrate fauna. The implications of the results for biodiversity conservation are discussed.
Display dispersion and micro-habitat use by the Malaysian peacock pheasant Polyplectron malacense in Peninsular Malaysia
Authors: McGowan Philip J. K. 
Published: July 2009

ABSTRACTThe spatial distribution of displaying Malaysian peacock pheasants was documented at a site in Peninsular Malaysia. Calling males were clustered and, therefore, were not evenly distributed throughout the available habitat. The location of these clusters differed between calling periods. An objective method of assessing micro-habitat structure at the forest-floor level was devised to investigate habitat use by displaying males. Habitat structure was measured at 197 points throughout the study site, both in areas used by the pheasant and in those areas not used by the pheasant. A DECORANA ordination revealed that two gradients explained much of the variation in micro-habitat structure. Male calling clusters were located in areas that were away from the river and more stable (e.g. fewer treefalls). Within these clusters, display scrapes were sited in areas that were more stable and were more influenced by the rivers than elsewhere within the area used by the calling males. It is suggested that the environmental gradients described by the ordination are more likely to determine the position of the calling cluster than individual habitat structure variables. Within calling clusters, however, it seems probable that the presence or absence of ground-level vegetation directly influences the siting of display scrapes.
Tropical tree seedling dynamics: recruitment patterns and their population consequences for three canopy species in Panama
Authors: de Steven Diane 
Published: July 2009

ABSTRACTA study of seedling demography of three shade-tolerant canopy tree species (Quararibea asterolepis, Trichilia tuberculata, and Tetragastris panamensis) was initiated to integrate with long-term studies of tree fruit production and of tree population dynamics on Barro Colorado Island, Panama. Over a five-year period, all seedlings (height <50 cm) and small saplings (height ≥50 cm to dbh 1 cm) were measured and monitored in permanent tree-centred transects (N = 10–11 trees per species). Survival rates increased with plant size class and were similar among species. Maximum height growth rates increased with increasing plant size, but average growth rates did not; this disparity suggests the importance of release from understorey suppression for long-term recruitment success. Among the three species, Quararibea had the lowest standing seedling densities and almost no sapling recruitment, whereas Tetragastris had the highest densities of both seedlings and saplings; Trichilia seedling and sapling densities were intermediate. In all three species, a few trees produced very high seedling and sapling densities in comparison with the sample average. All three species exhibited a year of exceptionally high new seedling recruitment during the study period; these good years were not coincident among the species but instead reflected the species' phenological differences. Since seedling survival becomes relatively constant and high after the first few years of life (c. 80% y−1), such large new cohorts persist as a year-class effect in the seedling population and thus maintain seedling numbers over time. The interspecific differences in seedling and sapling dynamics were consistent with overall 10-year trends of a declining Quararibea population, a stable Trichilia population, and an increasing Tetragastris population.
Vertical stratification of fruit bats (Pteropodidae) in lowland dipterocarp rainforest in Malaysia
Authors: Francis Charles M. 
Published: July 2009

ABSTRACTMistnets were set at ground level and 11–30 m above ground in lowland rainforest at Kuala Lompat in peninsular Malaysia, and Sepilok in Sabah, to compare the abundance of fruit bats in the subcanopy and at ground level. Capture rates in the subcanopy were up to 100 times greater than at ground level, averaging 3–7 bats per net-night. Species diversity was higher in the subcanopy than forest understorey. Two species that were frequently captured in the subcanopy,Megaerops wetmoreiandDyacopterus spadiceus, were previously thought to be rare. The abundance of Old World fruit bats in the subcanopy indicates that their roles in pollination and seed dispersal of Malaysian forest trees may be greater than previously recognized. Further research on foraging ranges, food selection and roosting habits is required to determine the overall importance of fruit bats in forest regeneration through seed dispersal, and the adequacy of existing reserves for their conservation.
Butterfly wing colour patterns and flying heights in the seasonally wet forest of Barro Colorado Island, Panama
Authors: Burd Martin 
Published: July 2009

ABSTRACTI investigated the extent to which adult butterflies with different wing colours display preferences for flying heights within a lowland tropical forest. Observations on eight colour groups, some of which comprised putative aposematic models and mimics while others contained nonaposematic species, were made from the forest floor and from a scaffold tower that reached above the canopy. Two groups (yellow pierids and papilionids and orange heliconiines) were most frequently observed in or above the canopy, and other groups were most frequently observed in or below the canopy. The evidence suggests that significant differences exist between some groups, but stratification does not occur among all colour groups. In particular, flight distributions of some mimicry rings overlap considerably. The light environments of different forest layers are variable, and the role that butterfly wing colours play in signalling or avoiding prcdation is little understood. However, the general lack of fine stratification of colour groups suggests that flight preferences do not occur because wing colours and patterns are especially cryptic against the background of particular forest layers.
The impact of simulated folivory on juveniles ofMetrodorea pubescens(Rutaceae) in a gallery forest near Brasília, Federal District, Brazil
Authors: Nascimento M. T. , Hay J. D. 
Published: July 2009

ABSTRACTA field experiment was conducted to test the effects of simulated folivory on leaf production, plant growth rate and mortality of small individuals ofMetrodorea pubescensin an evergreen gallery forest in central Brazil. Although complete defoliation decreased annual growth rate, both in absolute and relative values, it also stimulated leaf production. Mortality was observed only in individuals in the smallest size class, but was not statistically related to percentage defoliation. Recovery of completely defoliated individuals was rapid and after one year over 70% of their initial number of leaves was present. It is probable that insect folivory is not a direct cause of mortality of juveniles of this species.
An estimate of the numbers of forest elephants in Gabon
Authors: Barnes R. F. W. , Blom A. , Alers M. P. T. , Barnes K. L. 
Published: July 2009

ABSTRACTThe number of elephants living in the forests of Gabon was estimated by a stratified dung survey. The forest zone was stratified according to the distribution of the human population. The density of dung-piles was estimated for each stratum by the line-transect method. The total number of dung-piles in the forests of Gabon was estimated to be 52.43 × 106± 13.25 × 106. This gave an elephant estimate of 61,800 ±20,200. This survey shows Gabon to have one of the largest elephant populations on the continent.
The species richness of termites (Isoptera) under differing levels of forest disturbance in the Mbalmayo Forest Reserve, southern Cameroon
Authors: Eggleton Paul , Bignell D. E. , Sands W. A. , Waite B. , Wood T. G. , Lawton J. H. 
Published: July 2009

ABSTRACTFive forest plots of differing disturbance levels were sampled qualitatively for termites in the Mbalmayo Forest Reserve, southern Cameroon, using 100 m belt transects. Results showed a large reduction in species richness in two severely disturbed plots compared with a Near Primary plot, but little difference in two less disturbed regenerating plots; there is some evidence for a slight increase in species richness in the regenerating plots. Soil-feeders predominate in the primary and regenerating plots, but are greatly reduced in the severely disturbed plots. Wood-feeders appear to be more resilient to disturbance than soil-feeders, although their species richness is low in the most disturbed plots. The Termitinae are the dominant taxonomic group in the Near Primary plot, the Apicotermitinae in the less disturbed regenerating plots and the Macrotermitinae in the clear felled areas. There appears to be no secondary invasion of plots by savanna-associated species, and the small apparent increase in species richness in the less disturbed regenerating plots appears to be due to the influx of forest species usually associated with natural gaps.
Association between mites and leaf domatia: evidence from Bangladesh, South Asia
Authors: Rozario Shelley A. 
Published: July 2009

ABSTRACTMites use the leaf domatia of many woody plant species in Australasia and North America. Different types of leaf domatia, including pits, pockets and tuft domatia, are present among plant species in disturbed forests, plantations and gardens of Bangladesh in South Asia. These structures are frequently occupied by mites. Pooling across all species, domatia were often (66%) occupied by mites and used by them for shelter, egg-laying and development. On average, 70% of all mites on leaves were found in domatia, and over three-quarters of these were potentially beneficial (i.e. of predaceous or microbivorous taxa) to the plant. Further, when species were pooled across sites, leaves of domatia-bearing plants had significantly more predaceous mites than those of plants without domatia. These results are consistent with the patterns of mite-domatia association reported in Australasia, North America and North Asia and with predictions of mutualism between plants and mites.
Canopy closure and the distribution of tropical forest tree species at La Selva, Costa Rica
Authors: Lieberman Milton , Lieberman Diana , Peralta Rodolfo , Hartshorn Gary S. 
Published: July 2009

ABSTRACTAn index of canopy closure was used to estimate closure above the crowns of all trees ≥ 10 cm dbh in 11.11 ha of undisturbed lowland tropical forest at La Selva, Costa Rica. To correct for the efFects of tree size on canopy closure, we used the residual of the regression of the canopy closure index on tree size. Analyses were carried out for the 104 species which had ≥ individuals; a total of 3224 trees were included. Nine species were found to have their crowns in significantly more open conditions than expected by chance and five species were found to have their crowns in significantly more closed conditions than expected by chance (P < 0.05). The remaining 90 species (86.5% of the assemblage) were distributed at random with respect to canopy closure, occupying the available light conditions indiscriminately. Species occurring under higher light levels did not show a narrower range of tolerance than did other species. Most species were found to occur over a substantial proportion of the canopy closure continuum present in the stand; overlap among the great majority of species in the assemblage is extensive. The results support the view that tropical forests comprise assemblages of generalist tree species, and raise questions about the classic notions of gap-phase dynamics.
Litterfall and nutrient cycling in four Hawaiian montane rainforests
Authors: Vitousek Peter M. , Gerrish Grant , Turner Douglas R. , Walker Lawrence R. , Mueller-Dombois Dieter 
Published: July 2009

ABSTRACTThe mass of fine litterfall and nutrient circulation through litterfall were determined in four Melrosideros polymorpha/Cibotium spp.-dominated rainforests that differed in substrate age, parent material texture and annual precipitation on Kilauea and Mauna Loa volcanoes on the island of Hawaii. Three of the sites had rates of litterfall of 5.2 Mg ha−1 y−1; the fourth, which was on the most fertile soil, produced 7.0 Mg ha−1 y−1 of litterfall with higher concentrations of nitrogen and phosphorus. Tree ferns of the genus Cibotium cycled relatively large amounts of nitrogen, phosphorus and potassium through litterfall; their contribution to nutrient circulation was disproportionate to their mass in the forest, or in litterfall. The forest on the youngest substrate, which also had the lowest concentrations of nitrogen in litterfall, was fertilized with complete factorial combinations of nitrogen, phosphorus and a treatment consisting of all other plant nutrients. Additions of nitrogen increased the quantity and nitrogen concentration in litterfall during the second year following the initiation of fertilization, while no other treatment had a significant effect. Additions of nitrogen had no effect on litterfall mass or nutrient concentrations in the most nutrient-rich site.
Complex edge effects on soil moisture and microclimate in central Amazonian forest
Authors: Camargo J. L. C. , Kapos V. 
Published: July 2009

ABSTRACTWe investigated the influence of a four-year-old forest edge near Manaus, Brazil, on soil moisture and vertical profiles of air vapour pressure deficit (VPD) within the forest. Soil moisture was measured (with a neutron probe) 0, 5, 10, 20, 40, 60, 80, 100, 150 and 200 m into the forest from the edge, in undisturbed control areas, and in the pasture. Control soil moisture was better explained by rainfall in the previous 2 or 10 days than by longer-term totals. Soil water potentials ≤ – 1.5 MPa occurred at some forest locations during the driest period. The variation in soil moisture with distance from the forest edge was complex, with higher values just inside the edge and depleted zones at the edge and 40–80 m inside it. At a given height, VPD (standardized relative to measurements in the open) was not related to distance from the edge, but VPD increased more with height near the edge than in control areas. The complexity of the edge's influence and the contrast with earlier data from the same edge can be explained by the changing vegetation structure near the edge. Regrowth ‘seals’ the edge with more leaves that transpire and deplete soil moisture, while protecting the understorey just inside the edge from desiccating conditions. A mosaic of gaps of differing ages develops behind the edge, increasing the variation in microclimatic conditions near the ground and consequently in evapotranspiration and soil moisture.