bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy allocation patterns inBufo marinusfrom two habitats in Venezuela
Authors: Lampo Margarita , Medialdea Victoria 
Published: July 2009

ABSTRACTPatterns of energy allocation in the cane toad,Bufo marinus, were explored by analysing the seasonal variations in fat bodies and gonads in two populations subjected to different rainfall regimes and water permanency. In both populations, fat deposition occurred shortly after the rainy season due to an increase in feeding activity. In contrast, the timing of reproduction varied between sites according to the availability of suitable water bodies. Nevertheless, females with mature oocytes were predominant during the dry season, even in populations that bred throughout the year in permanent ponds. This suggests that seasonal variations in the nutritional condition of adults may also result in a tendency towards cyclicity in the reproduction ofB. marinusin tropical regions. Analyses of allometric relationships of reproductive and storage tissues with body weights indicated that the fractions of weights in reproductive tissues did not vary either with the size of females or between populations. On the contrary, not only did larger toads have proportionally larger fat bodies, but those from wet sites had greater fractions of weight allocated to fat bodies than those from dry sites. This suggests that reproductive output may be fixed in this species and, therefore, excess energy is allocated to fat bodies. Given that the initiation of ovarian cycles depends on the restoration of proper nutritional levels, energy stored in fat bodies during breeding may allow females to resume a new ovarian cycle shortly after spawning and thus maximize the number of reproductive events.
Protecting seeds from primates: examples fromDiospyrosspp. in the Lopé Reserve, Gabon
Authors: Tutin Caroline E. G. , Parnell Richard J. , White Frank 
Published: July 2009

ABSTRACTThe fruit of six species ofDiospyros(Ebenaceae) provide food for eight species of diurnal primates in the Lopé Reserve, Gabon. Both succulent flesh and immature seeds are eaten but patterns of consumption vary among the primate species. Interactions betweenD. mannii, which has very large fruit (9 cm × 7 cm) and seeds (5 cm × 2 cm), and primates were observed in detail.D. manniifruit are unusual, being covered by a dense mat of irritant hairs that are largely retained, but become looser on ripening, when fruit are abscissed. Primates do not eat immature seeds of this species but do predate on seeds of some otherDiospyrosspecies. Ripe flesh (and ripe seeds) ofD. manniiare eaten by gorillas and chimpanzees but not by monkeys. Comparison of fruit characters and of feeding patterns of primates for the sixDiospyrosspecies suggests that large seeds are potentially vulnerable to high levels of predation but the presence of irritant hairs provides protection during fruit development. Abscission of ripe fruit (shown only byD. mannii) appears to afford additional protection from predation on ripe seeds by arboreal monkeys. These observations underline the complexity of plant-animal interactions in tropical forests and suggest that some fruit characters have evolved to reduce seed loss during maturation.
Drought frequency changes in Sabah and adjacent parts of northern Borneo since the late nineteenth century and possible implications for tropical rain forest dynamics
Authors: Walsh Rory P. D. 
Published: July 2009

ABSTRACTArchival rainfall data are used to investigate changes in drought frequency and severity in Sabah and other parts of northern Borneo since the late nineteenth century. Two measures of drought severity are used: drought duration (given by the number of consecutive months with less than 100 mm rain); and drought intensity (indexed by the cumulative rainfall deficit below 100 mm per month of a drought sequence). Within northern Borneo dry periods are very short (>3 months) and infrequent in Sarawak, south-western Sabah, Brunei and central and western Kalimantan; droughts occur seasonally, but are comparatively short in north-western Sabah; droughts are less frequent) but more severe in eastern Sabah and parts of eastern Kalimantan. In coastal Sabah and Brunei, there has been a statistically significant increase in the frequency and severity of droughts since the late 1960s. At Sandakan, two drought-prone epochs in 1877–1915 and 1968–92 (each experiencing five droughts of at least 4 months duration) are identified, separated by a 52-year period that was nearly drought-free. At Sandakan also, the ecologically damaging 1982–3 drought was neither as long or severe as those of 1903 and 1915. Links with El Niño-Southern Oscillation events are found to be not as strong as previous studies have suggested. Possible implications of the spatial and temporal patterns in drought magnitude-frequency for differences in tropical rain forest character within the region are discussed.
Pollination of Amorphophallus johnsonii (Araceae) by carrion beetles (Phaeochrous amplus) in a Ghanaian rain forest
Authors: Beath Daniel D. N. 
Published: July 2009

ABSTRACTAmorphophallus johnsonii (N. E. Brown) flowers during April in the main rainy season in Ghana. Anthesis starts at dusk with fluid oozing from the upper spadix accompanied by a strong aminoid odour. Just after dark large numbers of carrion beetles (Phaeochrous amplus) and occasional dung fly species (Hemigymnochaeta unicolor and Paryphodes tigrinus) visit the inflorescences. The beetles become trapped in the lower spathe overnight and remain in the spadix until the following evening. Between 1630 and 1645 h the following day, the anthers produce long threads of sticky pollen. The trapped beetles escape just after dark by crawling up the spadix, past the dehisced anthers and fly away from the spadix tip. Marked beetles were seen to transfer pollen from male phase to female phase inflorescences. Successful fertilisation was only effected if pollen was transferred on the same night from a male inflorescence 30 m or less away. Pollen is psilate and typical of beetle pollinated Araceae. Berries ripen approximately 70 d after fertilization and ripen basisetally in the infructescence.
Habitat specificity and food preferences of an assemblage of tropical Australian dung beetles
Authors: Hill Christopher J. 
Published: July 2009

ABSTRACTTwo dung beetle assemblages from rainforest and open forest in the wet tropics of north-eastern Australia are described. The fauna was sampled using flight intercept traps, baited pitfall traps and light traps, with flight intercept traps being the most effective sampling technique. Dung beetle species were found to be highly habitat specific with a switch from rainforest to open forest assemblages occurring over tens of metres. The majority of the fauna was active at night. The most abundant species were attracted to a variety of food types but several species appeared to specialize on either dung or mushrooms.
Resource use within the crab-eating guild of the upper Kairezi River, Zimbabwe
Authors: Butler James R. A. , Marshall Brian E. 
Published: July 2009

ABSTRACTCape clawless otters Aonyx capensis and African mottled eels Anguilla bengalensis were suspected of reducing numbers of rainbow trout Oncorhynchus mykiss in the upper Kairezi River, Zimbabwe, by preying on them and competing for the river crab Potamon perlatus. The analysis of otter, eel and trout diets showed that this is unlikely. Trout was an unimportant prey item for otters, none were found in the stomachs of 13 large eels, and any predation was probably minimised by the low densities of these predators. Some competition was probably present because crabs occurred in the diets of otters (relative occurrence 41.9%), eels (63.2%) and trout (7.4%), but it was impossible to quantify. Since these predators shared the crab food resource, the guild concept provided the basis for an analysis of their potential competitive relationships. Comparisons between the sizes of crabs selected and those available suggested that resource partitioning was occurring. Trout selected small crabs from the invertebrate drift, and because they were restricted by their mouth gapes. Otters and large eels ate larger, more abundant crab sizes; it is proposed that they instead partition resources spatially by feeding in separate micro-habitats. Intraguild predation by otters on eels may benefit trout by reducing competition for aquatic insects. Competition within the guild probably recedes in the dry season, when eels become inactive.
Trophic relationships and food webs of the benthic invertebrate fauna of two aseasonal tropical streams on Bougainville Island, Papua New Guinea
Authors: Yule Catherine Mary 
Published: July 2009

ABSTRACTThe trophic ecology of Konaino Creek, a small mountain headwater stream draining rainforest in the aseasonal tropics on Bougainville Island, Papua New Guinea, was examined and a food web was constructed. The major source of energy in Konaiano Creek was allochthonous detritus, most of which had been terrestrially degraded to fine particulate organic matter rather than entering the stream as leaf litter. This fine detritus was collected by the filter-feeders (mostly Simuliidae and also Hydropsychidae) which formed the dominant functional feeding group (64.4% of the fauna). Thus filterers processed most of the allochthonous detritus and made the energy available to other trophic levels, rather than shredders (1.7% of the fauna) which perform this role in temperate headwater streams. Collector-gatherers made up 22.7% of the fauna, carnivorses, mostly Odonata, Decapoda (crabs) and Hydrobiosidae, comprised 2.8% of the fauna and grazer-scrapers made up 7.4%. The latter were inhibited by low instream production owing to heavy shading and the instability and abrasion of the substrate due to frequent spates. In comparison, the trophic ecology of the nearby, coastal, Bovo River (with a catchment mainly in rainforest but mostly cleared with introduced species at the study site) was quite different and it was dominated by collector-gatherers (74%) and grazer-scrapers (15%).
Distributional patterns of raptors along altitudinal gradients in the northern Andes and effects of forest fragmentation
Authors: Thiollay Jean-Marc 
Published: July 2009

ABSTRACTA survey of the diurnal raptor community (46 resident species) at five altitudinal levels from 100 to 4600 m was made in Venezuela using 106 1-km2sample quadrats and then compared with similar censuses (211 plots) in southwestern Colombia and eastern Ecuador. Six habitat types were defined and habitat preferences were measured from every encountered birds and from the association between individual abundances and the coverage of habitat types on plots. The overall species richness steeply declined with elevation in all three countries. The raptor community consisted mostly of tropical species that rapidly decreased in both abundance and frequency of occurrence with elevation. A small set of subtropical-temperate forest specialists partly replaced them at mid-elevation and only two species occurred in the paramo of Venezuela, against 5–7 in the other countries. Although originally the gradients were probably almost completely covered with forest, a large part of the raptor community is now composed of grassland species, three of them extending from the lowlands to the tree line. The relative impoverishment of the Venezuelan community, especially at upper levels, is attributed to a peninsular effect at the narrow extreme northern tip of the Andes and perhaps also to former forest fragmentation. Within some species, different subspecies had discrete altitudinal distributions and interspecific competition may explain differences in the range extension of some species between countries. Today, however, accelerating deforestation may result in a severe decline of forest-interior species and a probable reduction in the altitudinal range of at least some of them. Species naturally associated with forest gaps or edges usually tolerate a high degree of forest fragmentation and degradation but only one of them may become abundant in heavily human-altered woodlands. Few grassland specialists have become more widely distributed in the increasingly deforested landscapes.
Red crabs in rain forest on Christmas Island, Indian Ocean: activity patterns, density and biomass
Authors: Green Peter T. 
Published: July 2009

ABSTRACTThe red crabGecarcoidea natalisis the most abundant land crab on Christmas Island, Indian Ocean, and is found wherever native rain forest is still intact. The largest crabs grow to > 120 mm carapace width and reach > 500 g in mass. Red crabs are diurnally active, and moisture appears to be the most important factor governing surface activity – activity was nil below 77% RH, relatively low at 87% RH, and high above 95% RH. The crabs retreat to the interior of their burrows during dry periods, but emerge rapidly in response to rain. Because of their dependence on moisture for surface activity, red crabs show greater levels of activity during the wet season. Annual breeding migrations and moulting activity decreased the density of surface-active crabs at the main study sites for several weeks at the start of the wet season, and fruit and leaf fall caused dramatic local increases in the density of active red crabs. Density and biomass at the main study sites averaged 1.3 crabs m-2and 1454 kg ha-1, respectively, and 1.2 crabs m-2and 1137 kg ha-1at a total of five sites across the island. Rough calculations suggest that the island-wide population is at least 100 million individuals. Red crabs are the dominant consumer on the forest floor, and consume seeds, seedlings and leaf litter. Because they are both abundant and widespread, these animals have the potential to be the most important determinant of pattern and process in rain forest on Christmas Island.
Vertebrate predation of Brazil-nuts (Bertholletia excelsa, Lecythidaceae), an agouti-dispersed Amazonian seed crop: a test of the escape hypothesis
Authors: Peres Carlos A. , Schiesari Luís C. , Dias-Leme Cláudia L. 
Published: July 2009

ABSTRACTThe effects of escape distance to parental trees and tree clusters on the removal of Brazil-nut seeds (Bertholletia excelsa, Lecythidaceae) by vertebrate seed predators were examined in an entirely undisturbed stand of Brazil-nut trees of eastern Amazonia. Population density estimates, based on line-transect censuses, are also presented forBertholletiatrees and agoutis (Dasyprocta leporina), the most important scatterhoarder and seed predator of Brazil-nuts at this site. Seed removal experiments were conducted within and outside a naturalBertholletiatree cluster (castanhal) during both the wet and dry seasons. While there were no within-cluster effects of escape distance from parent trees on seed removal rates, overall seed removal within the cluster was significantly greater than that well outside the cluster. Moreover, removal rates in the wet season were consistently higher than those in the dry season both within and outside the tree cluster. Results suggest that the probability of early seed survival forBertholletia, in relation to distance to seed sources, operates on different spatial scales, and that seed predators allocate greater foraging effort to scattered seeds during the fruitfall (wet) season, when buried seed stocks are being cached by agoutis.
Plant successional pathways on Puerto Rican landslides
Authors: Myster Randall W. , Walker Lawrence R. 
Published: July 2009

ABSTRACTTo study regeneration on landslides, we counted the number of woody stems at least 1 m tall in 2 m × 5 m permanent plots on Puerto Rican landslides for 5 y and generated successional pathways for all plots in 16 different landslides using principal components analysis (PCA). PCA separated plots well, with early successional plant species (Cecropia schreberiana, Schefflera morolotoni, Alchornea latifolia, Gonzalagunia spicata) positively associated with axes I and II, and the negative portion of axis II associated with a mix of those species and mid-successional species (Inga vera, Piper glabrescens). Pathways generally showed (1) a positive association with axis I in early succession, (2) a negative association with both I and II later in succession, (3) little evidence of a decrease in the rate of succession, and (4) a lack of convergence of pathways over the 5 y of our study.
A comparison of fish diversity and abundance between nutrient-rich and nutrient-poor lakes in the Upper Amazon
Authors: Henderson Peter A. , Crampton William G. R. 
Published: July 2009

ABSTRACTA comparative study was undertaken of Amazonian fish diversity and density (abundance and biomass) in nutrient poor (blackwater) and richer (whitewater – várzea) habitats in the vicinity of Tefé, Brazil. The whitewater sampling sites, in the floodplain of the Rios Solimōes and Japurá, had high turbidity (Secchi disc 0.03–0.7 m), a conductivity of 64–110 μS cm–1 at 25°C and a pH of 6.6–6.9. The blackwater sites Lagos Amanã, Iamã and Tefé had a low turbidity (Secchi disc 2.0–2.2 m), a conductivity of 7–11 μS cm–1 at 25°C and a pH of 5.3–6.0. The fish communities of open water, floating meadow and forest margin were sampled. Both whitewater and blackwater sites held high diversity fish communities with many species in common. Whitewater habitats were more diverse yielding 108 species, compared with only 68 from blackwater. Fish density within floating meadow was estimated during high water April and May 1994, and low water October 1994 and March 1995. During the high water season fish biomasses in blackwater lakes (31.1 gm–2) were significantly greater than those of either whitewater lakes (13.4 gm–2) or whitewater river channels (3.45 g m–2). At low water, in October, whitewater channels were generally found to hold the highest fish biomass (204 g m–2) although in March a blackwater site yielded the highest fish biomass recorded (285.9 g m–2). The amount of floating meadow habitat within Whitewaters is however much greater than that in blackwaters. It is suggested that blackwaters may offer a stable habitat resulting in a high standing crop. In comparison, variation in conditions such as dissolved oxygen concentration in the whitewater may limit standing crop, but still allow periods of high productivity. Evidence was found for migration of fish from várzea lakes during periods of low oxygen availability. The high diversity and biomass of fish caught in both whitewater and blackwater lakes indicates that water acidity and conductivity are poor predictors of fish diversity and density in tropical floodplain lakes.
Heliotherms in tropical rain forest: the ecology ofKentropyx calcarata(Teiidae) andMabuya nigropunctata(Scincidae) in the Curuá-Una of Brazil
Authors: Vitt Laurie J. , Zani Peter A. , Lima A. Claudia Marinho 
Published: July 2009

ABSTRACTKentropyx calcarata(Teiidae) andMabuya nigropunctata(Scincidae) occur together in lowland tropical forest of the Amazon near the Rio Curuá-Una of Brazil. During the wet season of 1995 these lizards were common at forest edge along narrow roads that transect forest, in treefalls and along streams where sun reaches the ground. Both species are heliothermic, basking to gain heat. Their association with open patches results from high activity temperature requirements in an environment where sun availability is low. Null temperature distributions from forest and treefalls showed that forest does not offer opportunities for heat gain similar to treefalls. Moreover, the large proportion of time spent basking by both species indicates the importance of these patches for thermoregulation.K. calcaratais slightly larger in body length and heavier at a given body length thanM. nigropunctata. Both species are active foragers that seek out prey while moving through the habitat, feeding on orthopterans, roaches and spiders.M. nigropunctataalso eat significant numbers of insects that occur on vegetation, such as hemipterans. Prey size is larger inK. calcarataand associated with lizard body size. Prey size does not vary with body size inM. nigropunctataand prey are typically relatively small.Many of the ecological differences between these two lowland forest species appear to be historical: the ecology ofK. calcaratais very similar to that of other species ofKentropyxand teiids in general and the ecology ofM. nigropunctatais most similar to that of other studied species of south AmericanMabuya.
Use of Melastomataceae and pteridophytes for revealing phytogeographical patterns in Amazonian rain forests
Authors: Ruokolainen Kalle , Linna Ari , Tuomisto Hanna 
Published: July 2009

ABSTRACTSimilarities and differences among eight upland rain forest sites in Peruvian Amazonia were measured separately by using Melastomataceae, pteridophyte and tree species compositions and edaphic characteristics of the sites. All three plant groups showed a similar pattern among the sites, and this pattern could be explained by edaphic differences but not by geographical distances among the sites. The explicability of site-specific edaphic characteristics on the basis of geological history is discussed. The results suggest that both pteridophytes and Melastomataceae can be used as indicators of floristically different rain forest types that are edaphically defined. Distribution patterns of these plant groups can be studied much more rapidly than the patterns of trees and therefore both Melastomataceae and pteridophytes may be used in large scale phytogeographical studies that are urgently needed in the face of rapidly advancing deforestation.
Spatial distribution, fruit production and seed removal of a rare, dioecious canopy tree species (Aglaia aff. flavida Merr. et Perr.) in Papua New Guinea
Authors: Mack Andrew L. 
Published: July 2009

ABSTRACTAll mature individuals of Aglaia aff. flavida (Meliaceae) were mapped in a 260 ha study area at the Crater Mountain Biological Research Station in Papua New Guinea. Sixty-four reproductively mature trees were found in an aggregated distribution with a mean inter-tree distance of 88.9 m. The sample consisted of 35 female and 29 male trees with a mean shortest distance between sexes of 232 m. Seed production and seed removal of 22 female trees was monitored throughout the 1992 fruiting season. Female trees with in 200 m of male trees generally produced large seeds crops (> 100 seeds) whereas trees farther than 200 m from the nearest male had small seed crops (< 100 seeds) regardless of female size (DBH). Most seeds (63.2%, n = 3312) produced in a sub-sample of 22 trees came from the five most fecund trees, which also produced 74.1% of the seeds that were removed by vertebrate dispersers. Where a minority of a population of rare tropical trees produce the majority of progeny, sustainable harvest practices would be most effective where highly fecund individuals are identified and conserved.
Mineral nutrition and die-back inTerminalia ivorensisA. Chev. in Ghana
Authors: Agyeman Victor K. , Safo E. Y. 
Published: July 2009

ABSTRACTThis investigation examined the hypothesis that nutrient deficiency is related to the die-back ofTerminalia ivorensis. The study was conducted on three major soil groups in natural forest andT. ivorensisplantations. Five soil chemical factors, Total nitrogen, organic carbon, effective CEC, exchangeable calcium and magnesium, were positively related to die-back. Foliar nitrogen concentrations in trees suffering from die-back were almost 50% of those of healthy trees. The concentrations of magnesium in the leaves ofT. ivorensisexperiencing die-back were also low. Conversely, high concentrations of foliar calcium were associated with trees under stress. A highly significant relationship was observed between die-back ranks and leaf size.