bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil and air temperatures during prescribed cerated fires in Central Brazil
Authors: Miranda Antonio Carlos , Miranda Heloisa Sinátora , de Fátima Oliveira Dias Inês , de Souza Dias Braulio Ferreira 
Published: July 2009

ABSTRACTAir and soil temperatures were measured during dry season heading fires in three different physiognomic forms of native vegetation common in Central Brazil: cerrado sensu stricto (dense scrub of shrubs and trees), campo cerrado (open scrub), and campo sujo (open grassland with scattered shrubs). The vegetation was protected from fire for 15 y in some areas, had been burned once every two years, and once each year in other areas. The temperatures were measured with type-k thermocouples and recorded at intervals of 22.5 sees. Air temperature measurements were taken at 1, 60 and 160 cm. Maximum air temperatures ranged from 85°C to 840°C, and the duration above 60°C varied from 20 to 270 seconds. In the soil, negligible temperature increases were recorded below 5 cm depth, whereas at 2 cm maximum soil temperatures varied from 29 to 38°C. Possible influences of fuel load and moisture on the recorded data and on the behaviour of fire in the cerrado ecosystems are discussed.
Fine-scale distributions of tropical animal mounds: a revised statistical analysis
Authors: Fisher Martin 
Published: July 2009

ABSTRACTDescriptions of the fine scale distribution of organisms have frequently been used to investigate various ecological phenomena. Unfortunately, the most widely used spatial analysis techniques are based on single index statistics, which convey only minimal information about the biological processes underlying the studied distributions. Such statistics cannot detect changes in pattern over different scales, and cannot identify some types of distribution. Additionally, both the use of such statistics on the distribution of individuals which have a non-negligible size, and the frequent failure to use an edge correction for points close to the boundaries of a sampled area, have led to the over-reporting of ‘spaced out’ (‘regular’) distributions. Using two spatial distributions recently analysed with a single index statistic (termite mounds, and earthmounds created by termites), I illustrate the benefits gained from using the spatial functionsK(t), G(y)andF(x)to analyse both ‘point events’ and events which have a non-negligible size. These functions are considerably more informative about the nature of a spatial pattern and offer wide scope for the fitting of spatial models to biological distributions.
How many species of pimplines (Hymenoptera: Ichneumonidae) are there in Costa Rica?
Authors: Gaston Kevin J. , Gauld Ian D. 
Published: July 2009

ABSTRACTThe species richness of pimpline ichneumonids was examined using catches from a network of Malaise traps operated throughout Costa Rica. More species were caught at some sites than at reasonably well-collected sites in other countries. When corrected for area, the species richness of ‘Pimplinae’ and Pimplini in Costa Rica as a whole is greater than that for virtually any other region recorded to date. The local richness of both groups appears to be a function of their regional richness. Many of the species found in Costa Rica apparently have large geographic ranges.
The fate of mature African Acacia pods and seeds during their passage from the tree to the soil
Authors: Miller Maxine F. 
Published: July 2009

ABSTRACTThe fate of mature Acacia tortilis pods on the tree and ground and A. nilotica pods on the ground were investigated at a site in South Africa. Pods on Acacia trees were browsed only by giraffe whereas pods on the ground were browsed by kudu, impala, steenbok and duiker. In the absence of giraffe most A. tortilis pods fell from the tree to the ground. When giraffe were present they consumed most A. tortilis pods at tree level. Bruchids infested 21.6–54.0% of seeds within pods on the tree. Once fallen, in the absence of browsing ungulates, A. tortilis and A. nilotica pod and seed disappearance could be attributed to burial by termites and ants, seed consumption by rodents and to decomposition; when browsing ungulates were present they consumed most pods on the ground. Between 20.0–47.6% of A. tortilis and 31.0–58.0% of A. nilotica seeds on the ground were infested by bruchids. Ungulate browsing had no effect on bruchid infestation of seeds. This study exemplifies the importance of browsing ungulates as consumers of Acacia pods. Although survival of A. tortilis and A. nilotica seeds was greatest in the absence of browsing ungulates the survival of seeds following pod consumption by ungulates is unknown.
The effects of commercial mechanised selective logging on a transect in lowland rainforest in the Lopé Reserve, Gabon
Authors: White Lee J. T. 
Published: July 2009

ABSTRACTPlots of 1.25 and 11.25 ha were enumerated for trees and lianes ≥10 cm and trees ≥70 cm dbh respectively along a line transect in the Lopé Reserve, Gabon. In the small plot 511 trees and lianes of 116 species were found, and 175 trees of 48 species were present in the large plot. The plots were then subject to commercial mechanised logging and the enumerations were repeated once logging had been completed. The extraction rate was two trees ha−1and in the large plot a total of 31 (17.7%) trees representing 20.6% of the total original basal area died. Incidental damage in the small plot resulted in the loss of 10.8% of trees and lianes present, and 12.9% of the original basal area. Canopy cover was reduced by 10%. Damage levels were low compared with figures from most other tropical regions. The relevance of these figures to forest management in Gabon are discussed.
Avifauna in three vegetation types on Mundanthurai Plateau, South India
Authors: Johnsingh A. J. T. , Joshua Justus 
Published: July 2009

ABSTRACTPatterns of bird species diversity within three vegetation types were investigated by the line transect method on Mundanthurai Plateau, South India. Minimum numbers of species and individuals were seen in the study area during July and August. Such seasonal variation was more pronounced in riverine and dry deciduous forest than in the secondary vegetation which was avoided by most of the winter migrants. There was a greater species overlap between riverine and dry deciduous forest than between riverine and secondary vegetation.No relationship could be established between bird species diversity and tree species/foliage height diversity. The secondary vegetation had fewer specialized forest species and more generalists. Larger birds (>200 g) were rare but smaller ones (<50 g) were more common. The paper emphasizes that the conservation status of avifauna in managed forests in India needs to be assessed and monitored.
Seed dispersal by forest chimpanzees in Uganda
Authors: Wrangham Richard W. , Chapman Colin A. , Chapman Lauren J. 
Published: July 2009

ABSTRACTThe role of chimpanzees (Pan troglodytes) as seed dispersers in the Kibale Forest Reserve of western Uganda was assessed by analysing 1849 dung samples from two chimpanzee communities and by conducting germination trials on dispersed and non-dispersed seeds. Of the chimpanzee dung samples, 98.5% contained seeds, and fig seeds were the most common. The number of large seeds (>2 mm) per dung sample was often high, even for species with a relatively large seed. For example, Mimusops bagshawei has a 15-mm diameter seed and had an average of 26.5 seeds per sample. In addition, many seed species were found in the dung repeatedly over several months. Germination trials demonstrated that the species of seed commonly collected from dung were viable. Comparisons of both the rate and success of germination of chimpanzee-dispersed seeds with seeds collected directly from the parent trees, showed that gut passage increased the speed and probability of germination. The number of large seeds dispersed by the chimpanzee population was estimated at 369 large seeds km-1 day-1. We suggest that in Kibale, chimpanzees may play a more significant role in primary seed dispersal than implied by their low numbers and biomass.
Spatial distribution of gaps along three catenas in the moist forest of Taï National Park, Ivory Coast
Authors: Poorter Lourens , Jans Luc , Bongers Frans , Van Rompaey Renaat S. A. R. 
Published: July 2009

ABSTRACTThe spatial distribution of canopy gaps was analysed on three sites (total 71 ha) in the tropical moist forest of Tai National Park, Ivory Coast. Pattern analysis revealed a clustered distribution of gaps for two of the three sites. Catena dependent gap formation processes might explain local differences in the occurrence and distribution of gaps. Gap densities, sizes and percentage forest area in gap phase are higher on the upper and middle slope than on the crest or lower slope. As a consequence, regeneration of gap dependent tree species might be directed to the catena positions with the highest disturbance regime. The spatial distribution of gap dependent species can be clumped, not only due to the regeneration within gaps, but also due to the clustered nature of gap distribution on its own.
Structure, density and rarity in an Amazonian rainforest bird community
Authors: Thiollay Jean-Marc 
Published: July 2009

ABSTRACTA 100-ha quadrat of primary rainforest in French Guiana was ccnsused over two consecutive years by the mapping method, and a 24-ha core area was intensively mistnetted at the same time. More extensive surveys were conducted in successively larger areas including up to a large part of the forested interior of the country. From a total of 441 resident species found in the rainforest zone, 248 were regularly recorded within the 100-ha plot, 157 of which had mean densities of more than 1 pair km-2. The total estimated density of birds was at least 829 pairs km-2. Only two dominant species exceeded 20 pairs km-2, while 52% of all the species were represented by less than 2 pairs km-2. The distribution of body masses and niche characteristics among the bird community is given as well as the sample bias of the mistnet captures.Rare species were a key component of this primary rainforest community. Several patterns of rarity were described and no marked and constant relationships were found between rarity and body size, habitat, diet, foraging behaviour or social system. Among a wide set of environmental constraints, the population of each species may be limited by a different combination of factors. Habitat heterogeneity, low, irregular and seasonal food availability, interspecific competition or heavy predation pressure were prominent and likely causes of the low density of most species which in turn facilitated the high species richness.
Abundance and diversity of spiders from the canopy of tropical rainforests with particular reference to Sulawesi, Indonesia
Authors: Russell-Smith A. , Stork N. E. 
Published: July 2009

ABSTRACTSpiders were sampled by knockdown insecticide fogging from the canopies of tropical rainforest sites in Dumoga-Bone National Park, Sulawesi, at altitudes of 210 m, 300 m, 400 m and 1150 m. The density of spiders in the canopies increased with altitude from 0.97 m−2at 210 m to 14.6 at 1150 m−2. Species numbers increased five-fold between 210 m and 1150 m but species diversity (α of the log series) was greatest at 210 m and least at 1150 m, partially due to dominance of the fauna by few species at the highest altitude. Similarity between the spiders' communities (as measured by the Morisita-Horn index) was greatest between canopies at 300 m and 400 m and least at 400 m and 1150 m.Theridiidae were abundant in forests at all altitudes, Pholcidae and Salticidae in the lowland forests between 210 m and 400 m and Clubionidae, Linyphiidae and Oonopidae in the montane forest at 1150 m. Theridiidae was the most species-rich family at all altitudes (22−30% of all species). Other species-rich families included Araneidae (7−19%) and Salticidae (8−17%) in lowland forests and Clubionidae (12%), Oonopidae (10%) and Salticidae (12%) in the montane forest.Published information on density, proportion and diversity of spiders in canopies of both tropical and temperate trees is reviewed and the results discussed in relation to those from the present study.
Effects of annual fires on the production of fleshy fruits eaten by birds in a Brazilian Amazonian savanna
Authors: Sanaiotti Tânia M. , Magnusson William E. 
Published: July 2009

ABSTRACTThis study describes changes in the numbers of plant species fruiting during six years in I ha of Amazonian savanna on the right bank of the Tapajós River, Brazil. The work was based on fleshy fruits from tree and shrub-layer species eaten by birds. The area was burned in the first two years, protected during the following two years and burned again in the last two years. The number of tree species fruiting did not differ significantly between years with and without fire. The number of shrub-layer species fruiting was markedly reduced in years with fire, but the responses varied between species. Data on changes in shrub cover after two consecutive years of fire indicate that species also respond differently in terms of biomass lost due to fires. The two most abundant genera of shrubs, Miconia and Myrcia, had their cover reduced by up to 95% and 72% respectively. The area made available by the loss of shrubs was occupied mainly by the grass Paspalum carinatum. The fires and the decrease in the availability of fruits occurred during the season in which most species of birds breed. An interval of less than three years between fires is insufficient for shrub-layer species to recover.
The canopy gap regime in a secondary Neotropical forest in Panama
Authors: Yavitt Joseph B. , Battles John J. , Lang Gerald E. , Knight Dennis H. 
Published: July 2009

ABSTRACTWe mapped the occurrence of canopy gaps periodically between 1978 and 1990 in a 1.5 ha study plot within a 70-year-old (in 1978) Neotropical forest on Barro Colorado Island (BCI), Republic of Panama. The total area of the forest under canopy gaps in the plot averaged 4.3% (3.1% to 5.7%, 95% CI). There was high year-to-year variability in the rate of new gap formation. On the basis of repeated observations for four yearly intervals, the annual rate of new gap formation ranged from 0.45% y−1to 6.5% y−1. Most gaps were small. The mean size of individual gaps originally was 79 m2(range: 8-604 m2). However, large gaps (≥150 m2) occurred more frequently than expected for a secondary forest on BCI. Gaps closed rapidly the first year after formation but the rate of closure slowed thereafter. Despite the absence of any obvious environmental gradients, gaps were spatially clustered. Even in this relatively small plot, there seemed to be distinct gap-prone and gap-free areas.
Litter dynamics of recently harvested and mature bamboo savannas in a dry tropical region in India
Authors: Tripathi S. K. , Singh K. P. 
Published: July 2009

ABSTRACTAnalysis of litterfall, nutrient return and floor mass dynamics was made in mature and recently harvested bamboo savanna sites in a dry tropical region in India. The total annual litterfall was 590 and 267 g m–2in mature and harvested sites, respectively. Of the total litterfall, 58–77% by weight was contributed by leaf litter. Although litterfall occurred throughout the year, as much as 72–83% of the leaf litterfall was recorded during winter (December–February). Seasonal distribution of total litterfall was: rainy 12–22% of annual, winter 64–65% and summer 13–22%. Nutrient concentrations in bamboo leaf litter were low compared with the other species growing in the same region. Annual nutrient return through litterfall amounted to: 28–49 kg N ha–1, 1.32.9 kg P ha–1, 33–85 kg Ca ha–1, 12–32 kg K ha–1and 1.4–2.8 kg Na ha–1. While maximum accumulations of fresh litter on the ground occurred in summer, the partly decayed and particulate litter categories peaked in the rainy season. Decaying litter categories showed 1.5–3 times greater nutrient concentrations than the concentrations in fresh leaf litter. Marked immobilization of N and P occurred in decomposing leaf and particulate litter. The mean annual nutrient content of the floor was (kg ha–1): N 29–40, P 1.0–1.9, Ca 13.8–23.9, K 14.6–15.3 and Na 0.85–0.99. The annual turnover in litter layer was: 63–81% for dry mass and 64–90% for different nutrients.
Community structure and evolution of insectivorous bats in the Palaeotropics and Neotropics
Authors: Heller Klaus-Gerhard , Volleth Marianne 
Published: July 2009

ABSTRACTThe most diverse known communities of insectivorous bats in the Palaeotropics and Neotropics are similar in alpha diversity (number of species). However, they show distinct differences with respect to wing morphology and the echolocation behaviour of their component species. In the Palaeotropics, most bat families are clearly separated in wing morphospace. The morphological niche of Rhinolophidae is vacant in the Neotropics, but primitive echolocators using sound primarily for scanning the environment rather than for prey capture are much more frequent there than in the Palaeotropics. In our opinion, a large portion of this difference can be traced to the different evolutionary histories of the respective communities. Bat families of different geographical origin are involved and their foraging styles obviously evolved differently in the Old and New World.
The role of the white-eyed vireo in the dispersal ofBurserafruit on the Yucatan Peninsula
Authors: Greenberg Russell , Foster Mercedes S. , Marquez-Valdelamar Laura 
Published: July 2009

ABSTRACTWhite-eyed vireos (Vireo griseus) winter in the forests and secondary growth of the Yucatan Peninsula whereBursera simaruba(Burseraceae) is an abundant tree. Twenty-five per cent of all white-eyed vireos observed foraging visitedBurseratrees. In addition, presence and abundance of territorial white-eyed vireos in small forest patches were correlated with the size of theBurseracrop. Vireos were the most reliable dispersers ofBurseraseeds. These birds visited 32 of 35 trees observed for at least three hours. They accounted for approximately half of all bird visits, and two-thirds of the seeds dispersed. Most of the other species rarely visited (<5% of visits) or failed to remove seeds from the tree.Peculiarities of phenology and fruit structure may contribute to the tendency ofBurserato be dispersed by relatively few species. The capsules ofBurserafruits do not open when the fruit ripens; birds apparently locate ripe fruit using visual cues, although these are few. In addition, only a small portion of the crop ripens daily over a 7- or 8-month period. The vireo-Bursera simarubarelationship, found regionally on the Yucatan Peninsula, may result from the prolonged fruit ripening period (October-March), the relatively depauperate frugivore community and the relatively high density of smallBurseratrees in the hurricane-disturbed dry forests.Small trees at all times, and all trees from October to February, depend upon territorial vireos for continuous, highly efficient local dispersal of a small number of fruits. In March and April residual fruits ripen rapidly and synchronously, attracting a greater variety of visitors for broad spectrum dispersal during a period of food scarcity. Thus,Burserahas an unusual two-phase phenological pattern, perhaps alternately to take advantage of both specialized and opportunistic dispersers.
Ecological relationships between columnar cacti and nectar-feeding bats in Mexico
Authors: Valiente-Banuet Alfonso , Arizmendi María Del Coro , Rojas-Martínez Alberto , Domínguez-Canseco Laura 
Published: July 2009

ABSTRACTA bibliographical and herbarium investigation on the pollination syndrome of Mexican columnar cacti (tribe Pachycereeae) was conducted. Most Mexican species of columnar cacti show a chiropterophilic-pollination syndrome and they flower synchronously in March to May. The floral biology, reproductive system and visitors (to both fruits and flowers) ofNeobuxbaumia tetetzo, the most abundant and dominant columnar cactus of succulent forest in the Tehuacan Valley, were studied. This species reached densities ofc.1200 individuals ha−1. The batsLeptonycteris curasoaeandChoeronycteris mexicanawere its only pollinators, whilst a more diverse array of visitors disperse seeds. Contrary to findings for multiple pollinators of columnar cacti in extratropical deserts in North America, the relationships betweenN. tetetzoand nectar-feeding bats was strong and tightly coupled in Mexico.
Germination and seedling establishment of two native and one invading African grass species in the Brazilian cerrado
Authors: Klink Carlos Augusto 
Published: July 2009

ABSTRACTIntroduced either accidentally or purposefully for the creation of cultivated pastures, African grasses are becoming major invaders of ecological reserves and national parks of the Brazilian savannas, the cerrado. African grasses are particularly good colonizers of disturbed sites. Germination in the field and laboratory, and seedling establishment in the field were studied for the African species Andropogon gayanus Kunth var. bisquamulatus (Hochst.) Hack., and for the native species Echinolaena infltxa (Poiret) Chase and Schizachyrium tenerum Nees. The African species had a higher and faster germination rate than the two native species, but its seedling mortality was higher. The main cause of seedling mortality in the field was herbivory by ants. It is suggested that the invasion of cerrado by African grasses depends on the kind of management being practised.
Germination and development of sown mahogany (Swietenia macrophyllaKing) in secondary tropical dry forest habitats in Costa Rica
Authors: Gerhardt Karin 
Published: July 2009

ABSTRACTEffects of irradiance, root competition and water availability on germination and seedling establishment ofSwietenia macrophyllaKing were investigated in tropical secondary dry forests in the Guanacaste Conservation Area, Costa Rica. The fate of seeds sown in the beginning and the middle of the rainy season was studied in abandoned pasture, and in deciduous and semi-evergreen secondary forest. In the pasture, experimental treatments were mown and unmown grass. In the forest sites, thinning to increase light and trenching to reduce root competition were combined in a factorial design. Effects of moisture availability on germination were tested by supplementing natural rainfall in the initial rainy month. Germination at the beginning of the rainy season was not influenced by the supplementary water and was higher in the semi-evergreen forest than in the deciduous forest and pasture. In the forests, germination was little affected by irradiance or root competition. More seeds germinated in unmown than in mown pasture during the initial rains, but were not influenced by mowing when sown in the peak of the rainy season. Seedling mortality was low (>10%) during the initial months, but increased greatly in the dry season. Seedlings germinating early in the rainy season had a higher survival than those germinating later. The relatively slight effects of the different treatments and habitats on seedling establishment suggest that this species is rather insensitive to the large microsite variation in secondary vegetation.