bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth rates and mortality patterns of tropical lowland tree species and the relation to forest structure in Amazonian Ecuador
Authors: Korning Jørgen , Balslev Henrik 
Published: July 2009

ABSTRACTGrowth in diameter and the relationship between age and size are analysed for 22 tree species in Amazonian Ecuador using growth simulation by a stochastic technique that projects the diameter-age relationships of a species. Maximum diameter growth rates varied from 1.2 mm y–1 (Grias neuberthii) to 20.0 mm y–1 (Cecropia sciadophylla). Minimum growth rates ranged from almost zero in Neea divaricata to 2.4 mm y–1 in Mollia lepidota. Median growth rates ranged between c. 0.5 mm y–1 (Grias neuberthii, Neea divaricata) and 11.6 mm y–1 (Cecropia sciadophylla). The maximum simulated life-span spent between a DBH of 10 cm and the largest DBH of a species varied from 54 y (Cecropia sciadophylla) to 529 y (Neea divaricata). Fast growing species and species that potentially can grow old showed a convex survivorship curve, whereas slower growing species and species that do not grow very old showed sigmoid, linear and convex survivorship curves. The species were grouped according to their DBH-height relationship and according to their maximum age, maximum growth rate, and maximum DBH. The groups probably reflect different light requirements. A negative correlation was found between maximum age and mortality rate. Growth rates vary within species, thus the largest tree is not necessarily the oldest.
Population size structure and sex ratios in some woodlice (Crustacea: Oniscidae) from southern Africa
Authors: Dangerfield J. M. , Telford S. R. 
Published: July 2009

ABSTRACTThe population size structure and adult sex ratio were recorded for four indigenous and one introduced species of terrestrial isopod from southern Africa. Interspecific variation was considerable with either discrete or continuous distributions indicative of the production of separate cohorts or continuous recruitment. Intraspecific variation was also considerable particularly in species such asAphiloscia viliswhich can be found in diverse habitats. Sex ratios were consistently female biased, a result consistent with observations made on temperate species. These observations, and a consideration of sexual dimorphism based on body mass, suggest that phenotypic plasticity may be an important tactic in the life histories of tropical woodlice and that in some populations the potential exists for strong sexual competition and complex mating systems.
Effects of soils and topography on the distribution of tree species in a tropical riverine forest in south-eastern Brazil
Authors: Oliveira-Filho Ary T. , Vilela Enivanis A. , Carvalho Douglas A. , Gavilanes Manuel L. 
Published: July 2009

ABSTRACTThe relationships between soil properties, topography and tree species distribution were analysed in a tropical riverine forest at the margins of the Rio Grande, in Bom Sucesso, state of Minas Gerais, south-eastern Brazil. The forest was sampled by three 0.18 ha plots, with each plot made up of eight contiguous 15 m X 15 m quadrats, four of which were placed at the river margin and the remaining four in the forest interior. A canonical correspondence analysis indicated that the species' density distribution was significantly correlated with some soil chemical characteristics and topographical features. The soils of the three sample plots showed statistically significant differences for the levels of Ca, Mg, K and pH, with the fertility (expressed by the cation exchange capacity) increasing from Plot I to Plot III. These variations were mainly explained by the first canonical axis while the second was strongly correlated with topographical variables, separating the quadrats into two groups: those of the higher and steeper sites from those of the lower sites. The only soil property that was significantly different in lower and upper sites was the concentration of phosphorus. No significant difference in tree species distribution was found between river margin and interior quadrats, certainly because this forest sector lies on the outer side of a curve of the river where erosion is currently building high and steep river banks and forcing the forest to retreat. A tentative ecological classification of the 30 most abundant species according to their habitat preference in terms of soil fertility and topographical sites, and to their growth strategy in the forest dynamics, is presented. It is suggested that these factors play an important role in promoting the coexistence of tree species in this type of forest.
Phenological niches of coexisting serotinous plants in the Namib Desert
Authors: Günster Antje 
Published: July 2009

ABSTRACTTiming of germination and flowering under different environmental conditions was investigated in four coexisting serotinous desert plants: Blepharis grossa (annual herb), Geigeria data, Geigeria ornativa (facultative perennial herbs) and Petalidium setosum (perennial shrub). Germination patterns were similar under varying environmental conditions in the study species, except for P. setosum, which germinated later when conditions were less favourable. B. grossa always germinated early, G. alata and G. ornativa later, which could be explained by differences in their seed dispersal mode. Thus no obvious niche separation in timing of germination was indicated in the study species. Flowering periods varied between seasons rather than between species and no niche separation in flowering times existed between the study plants. This might indicate that either interspecific competition plays a minor role in a community of desert serotinous plants or that niche separation exists in other components of the plants' niche, such as seed dispersal, seedling establishment and/or microhabitat selection.
The use of a common epiphytic lichen as a bioindicator of atmospheric inputs to two Venezuelan cloud forests
Authors: Gordon Catriona A. , Herrera Rafael , Hutchinson Tom C. 
Published: July 2009

ABSTRACTThe chemistry of epiphytic lichens was determined in two Venezuelan cloud forests adjacent to the Caracas Valley at Altos de Pipe and El Avila National Park. This is the second component of a two-part study examining the chemistry of fogs and their effects on sensitive biota in these forests. The widespread lichen Parmotrema madagascariaceum was chosen as an indicator of trace metal input. Background lichen collections and transplant experiments were carried out to evaluate spatial trends in atmospheric depositon of trace metals at different altitudes and exposures of the two montane locations. Elevated concentratons of metals including Pb and Zn were seen in lichen tissue and associated bark. Lead levels in lichens reached 190 μg g-1dry wt. Lichens transplanted from relatively ‘clean’ to more polluted sites showed significant increases of metals, particularly Pb. Increases of up to 6.3 μg Pb g-1mo-1after 6 and 10 months were recorded relative to background andin situlichen material. In contrast, when lichsens were reciprocally transplanted in nylon net bags from less to more exposed sites there was a significant decrease in Pb and Zn concentrations after 6 and 10 months. With long-term exposure to elevated concentrations of these trace metals epiphytic lichens, as well as other sensitive cloud forest biota, may be at risk of decline.
Plant phenology in relation to water availability: herbaceous and woody species in the savannas of northern Cameroon
Authors: Seghieri J. , Floret Ch. , Pontanier R. 
Published: July 2009

ABSTRACTPhenological patterns of herbaceous and woody plants well represented in the Sudano-Sahelian savannas of northern Cameroon were studied in relation to water availability in three contrasted soil types. Mean annual precipitation in this region is 800 mm, entirely restricted to the period May-June to September-October, but redistribution of rainwater by varying soil substrates leads to considerable heterogeneity in available water resources for plants. Results are discussed in terms of probable competition for water resources among co-occurring plants and the adaptations shown by observed patterns to prevailing environmental conditions. Water stress is seen to be a limiting factor to plant growth but does not constitute the sole trigger for the phenological phases observed, nor is it the principal factor responsible for the preponderance of annual species in the herbaceous stratum.
Daily activity patterns of small mammals in a cerrado area from central Brazil
Authors: Vieira Emerson Monteiro , Baumgarten Leandro Cláudio 
Published: July 2009

ABSTRACTWe investigated the daily activity patterns of four species of small mammals in an area of cerrado habitat in central Brazil. We checked live traps at 3-hour intervals during the night.Bolomys lasiurusandCalomjis tenet(Rodentia, Muridae), two potential competitors, differed significantly in their daily activity patterns.Bolomys lasiurushad peaks during the twilight, whereasC. tenerhad a more constant activity through the night, with a peak between 2200 and 0100 h.Thalpomys cerradensis(Rodentia, Muridae) was more active immediately after sunset and in the last three hours before sunrise.Thylamys velutinus(Marsupialia, Marmosidae) was strictly nocturnal with greater activity early in the night. Other factors, such as predation pressure or diet, may be important in determining the activity patterns observed in this study.
Variation in reproductive characteristics of the stream frog Colostethus trinitatis on the island of Trinidad
Authors: Cummins Clive P. , Swan Mary J. S. 
Published: July 2009

ABSTRACTWe compared reproductive characteristics of the dendrobatid frog Colostethus trinitatis at the Tamana cave in the Central Range hills and at five forest stream sites in the Northern Range hills of Trinidad. There were significant differences between sites in adult female body size, intraovarian clutch size (in absolute terms and relative to body size) and the size of tadpoles carried by male frogs. Clutch sizes ranged from 6 to 13 in the Northern Range samples and from 12 to 26 at Tamana. Adult male body size was similar at all sites. Tadpoles carried by male C. trinitatis at Tamana were significantly smaller (mean length 14.2 mm) than those carried by males at the five Northern range sites (mean length 16.4–16.7 mm). The smallest clutches and largest tadpoles were found at Mount St Benedict, where there was evidence of size-selective predation on tadpoles by fish. Tamana, where clutches were large and tadpoles small, differed from the Northern Range sites in terms of the physical environment (cave vs forest) and the abundance of invertebrates. We discuss possible ultimate and proximate causes of the differences in clutch size and tadpole size, particularly size-selective predation and availability of food.
Aspects of the population biology of the gregarious tree Cordia elaeagnoides in Mexican tropical deciduous forest
Authors: Van Groenendael Jan M. , Bullock Stephen H. , Pérez-Jiménez L. Alfredo 
Published: July 2009

ABSTRACTCordia elaeagnoides is locally important within a large area of southern México as a highly gregarious canopy tree of dry forest and as a timber species. Its recruitment is problematic so studies of its reproduction and population dynamics were undertaken. The distylous flowers are apparently self-compatible, and pollination and seed dispersal are by wind. Pre-dispersal mortality is largely from embryo abortion, and post-dispersal predation is mostly by generalist rodents. Some seeds may survive in enforced dormancy for two or more years. Recruitment was apparently absent for more than a decade, but had previously occurred within established stands, where size classes were interspersed at random. Population size structure suggests that recruitment over the last century occurred in several pulses. Growth rates determined from ring counts and remeasurement of marked trees support a size-age relationship. The youngest reproductive trees are estimated to be about 18 years old, and about 5% of the present population is over 95 years old.
Species richness and density of ground herbs within a plot of lowland rainforest in north-west Borneo
Authors: Poulsen Axel Dalberg 
Published: July 2009

ABSTRACTIn a I-ha plot all ground herb species were recorded. Within the plot selected properties were investigated in three 20 m × 20 m subplots. The number of ground herb species and individuals in the subplots were lowest near to a local hilltop and they increased towards the lowest part of the plot. There was no significant difference in canopy openness, or in thickness of leaf litter layer, between the upper and lower subplots. In the upper subplot the soil layer was thin and the weathered bedrock was close to the surface. In the lower subplot the soil was much deeper. The pH and concentrations of Mg were significantly lower and %loss-on-ignition, total P and total N concentrations were significantly higher in the upper subplot. Elevation and soil moisture were significantly correlated in the upper 10 cm of soil. It is not possible to select any one abiotic property as being the critical determinant of the gradient of ground herbs. However, it is suspected that the availability of water in the topsoil, particularly after droughts, may be more important than the soil nutrients in limiting herb distribution.
A comparison of ground-dwelling small mammal communities in primary and secondary tropical rainforests in China
Authors: Wu De-Lin , Luo Jia , Fox Barry J. 
Published: July 2009

ABSTRACTTrapping was conducted in primary and secondary forests to investigate the effects of past logging on small mammal communities. Thirteen I-ha sites were snap-trapped for three consecutive days in tropical monsoon rainforest in Xishuangbanna Nature Reserve, southern China. A total of 3900 trap-days yielded 198 captures, of which 118 were in the primary forest and 80 in the secondary forest. A total of 12 ground-dwelling species (eight Rodentia, Muridae; three Insectivora, Soricidae; one Insectivora, Erinaceidae) were caught, five (all Rodentia, Muridae) occurred in the primary forest and 11 in the secondary forest. The most abundant species wasNiviventer confucianus, accounting for 62% and 39% of the total captures in the primary and the secondary forests, respectively. In the secondary forest the mean abundances of the two dominant species,N. confucianusandMaxomys surifer, were reduced, and a non-commensal form ofRattus rattusdisappeared, butN. fulvescensshowed no change whileMus pahariincreased. The seven species which occurred only in secondary forest had very low abundance. Overall, the multivariate Mantel test showed the two communities to be significantly different. After logging, species diversity increased, and the two dominant species had increased body mass and their mean abundance decreased.
Changes in tree species abundance in a Neotropical forest: impact of climate change
Authors: Condit Richard , Hubbell Stephen P. , Foster Robin B. 
Published: July 2009

ABSTRACTThe abundance of all tree and shrub species has been monitored for eight years in a 50 ha census plot in tropical moist forest in central Panama. Here we examine population trends of the 219 most numerous species in the plot, assessing the impact of a long-term drying trend. Population change was calculated as the mean rate of increase (or decrease) over eight years, considering either all stems ≥10 mm diameter at breast height (dbh) or just stems ≥100 mm dbh. For stems ≥10 mm, 40% of the species had mean growth rates <1% per year (either increasing or decreasing) and 12% had changes ≥5% per year. For stems ≥100 mm, the figures were 38% and 8%.Species that specialize on the slopes of the plot, a moist microhabitat relative to the plateau, suffered significantly more declines in abundance than species that did not prefer slopes (stems ≥10 mm dbh). This pattern was due entirely to species of small stature: 91% of treelets and shrubs that were slope-specialists declined in abundance, but just 19% of non-slope treelets and shrubs declined. Among larger trees, slope and non-slope species fared equally. For stems ≥100 mm dbh, the slope effect vanished because there were few shrubs and treelets with stems ≥100 mm dbh. Another edaphic guild of species, those occurring preferentially in a small swamp in the centre of the plot, were no more likely to decline in abundance than non-swamp species, regardless of growth form. Species that preferentially colonize canopy gaps in the plot were slightly more likely to decrease in abundance than non-colonizing species (only for stems ≥10 mm dbh, not ≥100 mm). Despite this overall trend, however, several colonizing species had the most rapidly increasing populations in the plot.The impact of a 25-year drying trend and an associated increase in the severity of the 4-month dry season is having an obvious impact on the BCI forest. At least 16 species of shrubs and treelets with affinities for moist microhabitats are headed for extinction in the plot. Presumably, these species invaded the forest during a wetter period prior to 1966. A severe drought of 1983 that caused unusually high tree mortality contributed to this trend, and may also have been responsible for sharp increases in abundance of a few gap-colonizers because it temporarily opened the forest canopy. The BCI forest is remarkably sensitive to a subtle climatic shift, yet we do not know whether this is typical for tropical forests because no other large-scale censuses exist for comparison.
Diet, growth and movements of juvenile crocodiles Crocodylus porosus Schneider in the Klias River, Sabah, Malaysia
Authors: Sah Shahrul Anuar Mohd , Stuebing Robert B. 
Published: July 2009

ABSTRACTA total of 14 spotlight surveys were carried out from January 1992 to February 1993 along 37 km of the Klias River in north-western Sabah, Malaysia. Surveys were at low tide between 1900 and 0600 h from a survey boat at 15 km h−1 by two observers. A total of 221 sightings were made, which varied between 2 and 29 per survey (mean 15.8). A total of 55 juvenile crocodiles were captured, with 16 recaptures. Calculated density was 0.9–1.8 individuals km−1, while the estimated crocodile population was 46.1 ± 10.2 (SD) for the survey area. Percentage sightings according to total length were: 42% ≤0.5 m; 40% >0.5-≤1.0 m; 5% > 1.0-≤3.0; and 13% eyes only. Recapture of 16 tagged juveniles suggested that hatchlings ≤0.5 m total length remained within >0.5 km of their release point for at least one month, and juveniles 0.5-≤1.0 m more than one year. Hatchlings had growth rates between 0.01 and 0.08 cm d−1 and 0.3 and 1.5 g d−1, while larger juveniles grew at least 0.11 cm d−1 and 2.7–2.9 g d−1. Stomachs of hatchlings and juveniles contained crabs (Ocypodidae), prawns (Atyidae), insects and small fish (Hemiramphidae). Relatively large numbers of juvenile Crocodylus porosus (82.4%) in the Klias River suggests that the area, though under hunting pressure, is desirable as a site for the conservation of C. porosus in the Sabah.
Relationships between herb layer and canopy composition in a tropical rain forest successional mosaic in Singapore
Authors: Turner I. M. , Tan H. T. W. , Chua K. S. 
Published: July 2009

ABSTRACTClusters of four circular forest plots, 0.2 ha in total area, were inventoried for canopy tree (≥30 cm gbh) and terrestrial herb floristic composition at 46 sites in the Central Catchment Nature Reserve, Singapore. The Nature Reserve covers a complex mosaic of lowland tropical forest of different successional stages, with much of the area covered in secondary forest 50–100 years old developed on exhausted agricultural soils. A total of 449 species of tree and 59 species of terrestrial herb were recorded from the clusters. Facultatively-terrestrial epiphytes were excluded from the analysis. Possible reasons for the low herb diversity are discussed. There was a marked similarity between ordinations (detrended correspondence analysis) of the clusters based on tree canopy composition weighted by species relative contribution to cluster total basal area and the herb flora composition, with a highly significant correlation between first axis scores of the two ordinations. Both ordinations showed the three clusters from freshwater swamp forest to be highly distinctive from the rest. The two forest strata exhibited a parallel response to the successional gradient, though the low diversity and patchy distribution of the herb flora blurred the distinction between primary and secondary communities more clearly seen in canopy composition.
Production of metabolic gases by nests of the termiteMacrotermes jeanneliin Kenya
Authors: Darlington J. P. E. C. , Zimmerman P. R. , Greenberg J. , Westberg C. , Bakwin P. 
Published: July 2009

ABSTRACTNests of a fungus-growing termiteMacrotermes jeannelidischarge all their metabolic gases through a single outlet to the atmosphere. This made it possible to measure the production of metabolic gases, and the rates of water loss, for intact nests in the field. Rates of production of carbon dioxide and methane from isolated nest components (different termite castes and intact fungus combs) were measured. Using previously published nest population data and fungus comb weights in relation to nest size, the expected gas production rates for intact nests were calculated. These estimates were compared with direct observations of the gaseous outflow from intact nests. The rates were in reasonable agreement, but some nests emitted excess carbon dioxide, probably produced by respiration of tree roots and non-termite soil organisms. Large nests may have a total gas outflow of 100,000 to 400,000 1 d–1including 800 to 1500 1 d–1of CO2and 0.5 to 1.3 1 d–1of CH4. Nests lose water at the rate of up, to 13 1 d–1gross, but allowing for ambient humidity the net water loss was up to about 5 1 d–1. Some of this is metabolic water, but the larger proportion comes from the soil. Area-based estimates of gas production were made for this and two other species ofMacrotermes, but they are not accurate because the field distribution and mound density are not adequately known.
Abundance and diversity of soil macrofauna in northern Botswana
Authors: Dangerfield J. M. 
Published: July 2009

ABSTRACTThe abundance and diversity of soil macrofauna were assessed in a range of vegetation types in northern Botswana. Hand-sorting of soil was used to extract all fauna greater than 2 mm body length from sandy soils in both the dry season (June) and towards the end of the single rainy season (February). Abundance varied significantly between samples from within a sampling location, within a vegetation type and occasionally between seasons. Greater densities were found in wet season samples from locations within closed canopy woodland except where permanent water was a significant feature of the habitat. Overall abundance was comparable to published estimates from more moist tropical and temperate habitats suggesting an important role for soil macrofauna in semi-arid systems. Ordinal level diversity also varied significantly within vegetation types and with season.
Erratum
Authors: Green P. 
Published: July 2009

Green, P. T. (1997)Red crabs in rain forest on Christmas Island, Indian Ocean: activity patterns, density and biomass. Vol. 13 Part 1: 17–38. On page 29 the phrase: “but a significant correlation existed across sites (r=0.81, n=44, P<0.001).” should read: “but a significant correlation existed across sites (r=-0.69, n=44, P<0.001).”On page 33 the phrase “but the same correlation accounted for 81% of total variation when all sites were analysed together.” should read: “but the same correlation accounted for 48% of total variation when all sites were analysed together.”