bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

ABSTRACTWe 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

ABSTRACTVarious 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

ABSTRACTFruit 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

ABSTRACTFruit 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

ABSTRACTThere 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

ABSTRACTAtmospheric 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

ABSTRACTNanophyes 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

ABSTRACTIn 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

ABSTRACTAnt 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

ABSTRACTData 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

ABSTRACTMean 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

ABSTRACTThe 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

ABSTRACTA 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.
Litterfall and nutrient fluxes in two montane tropical rain forests, Colombia
Authors: Veneklaas Erik J. 
Published: July 2009

ABSTRACTLitterfall was sampled during one year in two undisturbed Andean forests at altitudes of 2550 and 3370 m in the Colombian Cordillera Central. Total small litterfall at 2550 and 3370 m was 7.03 and 4.31 tha-1y-1respectively, of which 4.61 and 2.82 were leaves, 1.06 and 0.76 woody parts, 0.66 and 0.27 reproductive parts, 0.22 and 0.23 epiphytes, 0.47 and 0.23 unclassified.Clear differences were also found in nutrient concentrations, both between different litter fractions from one site and between equivalent litter fractions from different sites. Weighted mean concentrations for total small litterfall were (mgg-1, at 2550 and 3370m respectively): 11.7 and 7.3 for nitrogen; 0.86 and 0.44 for phosphorus; 8.4 and 3.1 for potassium. Comparison of nutrient concentrations in crown leaves and shed leaves indicated important reallocation of nitrogen (39% at both sites) and phosphorus (45% at 2550m, 65% at 3370m) before leaf shedding.The results for litterfall amounts, litter nutrient concentrations and reallocation of nutrients in the two forests are consistent with such data obtained in other montane forests in the wet tropics.
Comparative biology of Neotropical epiphytic and saxicolous Tillandsia species: population structure
Authors: Bennett Bradley C. 
Published: July 2009

ABSTRACTIn comparing the population structure of epiphytic and saxicolous Tillandsia species I found no significant differences between polycarpic species. Epiphytic T. ionochroma populations had a higher seedling:adult ratio than saxicolous T. ionochroma populations, but the difference was not statistically significant. Tillandsia ultriculala, a monocarpic epiphyte, had a significantly higher seedling:adult ratio than the polycarpic species. T. utriculata's higher ratio may result from its greater seed production and lack of vegetative propagation. Unlike the polycarpic species, all adult-size rosettes grow from seeds in T. utriculata. Tillandsia sphaerocephala, an obligate saxicole, occurred in larger clusters (i.e. more rosettes per genet) than T. ionochroma. The increased tendency for vegetative reproduction in T. sphaerocephala suggests that spatial patchiness is less of a constraint than with epiphytes.
Responses of Amazonian rain forest birds to habitat modification
Authors: Johns Andrew D. 
Published: July 2009

ABSTRACTBird species were surveyed in a variety of habitat types in a lightly populated area of western Brazilian Amazonia. Habitats surveyed were untagged forest, selectively logged forest, ‘capoeira’ (scrub regenerating on cleared land), cropfields, and an isolated 35 ha forest ‘island’. All habitats were within a few kilometres of each other. Many bird species were found to occur in all or most habitats, although the similarlity of the species assemblages dropped with increasing levels of disturbance of the natural vegetation. Certain understorey insectivores common in untagged forest were rarely observed in other habitats; disturbed areas contained higher numbers of flycalching insectivores or birds feeding on both insects and fruit, some of which were open-country rather than forest species. The avifauna of the forest ‘island’ was more similar to that of regenerating scrub than to that of tall forest, and the persistence of forest species was attributed to their ability to move to and from nearby continuous forest areas.
Howler monkeys (Alouatta palliata), dung beetles (Scarabaeidae) and seed dispersal: ecological interactions in the tropical rain forest of Los Tuxtlas, Mexico
Authors: Estrada Alejandro , Coates-Estrada Rosamond 
Published: July 2009

ABSTRACTThe dispersal of seeds by howler monkeys (Alouatta palliata) and the activity of dung beetles in modulating the fate of the dispersed seed were studied at Los Tuxtlas, Mexico. Howlers consumed the fruits of 35 species of plants. The seeds of 28 of these were dispersed by the monkeys. The majority (≥90%) of the seeds dispersed by monkeys were destroyed by rodents. Rapid relocation and burial of dung by dung beetles resulted in accidental relocation and burial of large numbers of seeds shortly after deposition. Faecal clumps (20 mg) remained on the ground for an average of only 2.5 h (range 1–3 h). Ball rolling beetles transported balls up to 5.0 m from the site of deposition (range 1–5 m). Burrowing and ball-rolling dung beetles buried seeds at depths ranging from 2.5 to > 12.0cm. The deeper a seed is buried, the less likely it is to be found and eaten by rodents. Eighty percent of the species used by Alouatta as sources of fruit at Los Tuxtlas benefited by the dispersal and post dispersal service provided by howlers and dung beetles respectively. Seasonality in dung beetles abundance in the forest may influence the number of seeds per species escaping post-dispersal predation during the year. Dung beetles play not only an important ecological role in the recycling of matter and energy in the ecosystem, but also in the process of rain forest regeneration.
Pattern in a derived savanna in Nigeria
Authors: Greig-Smith P. 
Published: July 2009

ABSTRACTAll woody growth was enumerated in three transects, each 960 m x 20 m, in derived savanna in the Olokemeji Forest Reserve in south-west Nigeria. The data for species density, species basal area and stem girth classes were analysed by nested-block analysis of variance and covariance. The use of ‘total covariance’, the sum of all covariances at a block size, contributes to understanding of the pattern present.Three scales of pattern were evident. Patchiness at 160–320 m is interpreted as a response to soil differences or to the pattern of previous farming, which may itself have been determined by soil differences. Patchiness at 20–40 m is attributable to varying intensity of burning. At the smallest scale, of 10 m, there is evidence of regularity of distribution resulting from interference between individuals, possibly due to competition for water.