bluuebunny/crossref_metadata_2025 huggingface dataset:
Seed-dispersal ofVouacapoua americana(Caesalpiniaceae) by caviomorph rodents in French Guiana
Authors: Forget Pierre-Michel
Published: July 2009

A possible mutualistic dispersal system between a large-seeded tree of French Guiana,Vouacapoua americana(Caesalpiniaceae), and caviomorph rodents,Myoprocta exilisandDasyprocta leporina, is described. Mast fruiting ofVouacapouaat the beginning of the wet season coincides with scatter-hoarding seed dispersal. During the wet season, almost 100% of marked seeds on three sites were removed: nearly 70% were buried and the rest were eaten by mammals. Unburied seeds were attacked by insects and/or lost their ability to germinate. Rodents preferred ungerminated seeds, and had no interest in germinated seeds. Seeds were buried individually near natural objects such as palms, branches, logs, lianas, roots and trees. After predation by rodents, seedling distribution did not differ from seed distribution. Most seeds were transported less than 5 m from the feeding plots but some were carried as far as 22.4 m. Between 40 and 85% of dispersed seeds were retrieved during the following month by rodents and eaten. The disinterest of caviomorph rodents in germinated seeds, because of rapid exhaustion of endosperm reserves, prevents feeding from hoardedVouacapouaduring the long dry season when resources are scarce. Seedlings emerging from forgotten or abandoned cached seeds appear to increase the recruitment ofVouacapoua americana.
The coexistence of two frugivorous bat species and the phenology of their food plants in Brazil
Authors: Marinho-Filho Jader S.
Published: July 2009

Carollia perspicillata and Sturnira lilium are two species of abundant and widely distributed phyllostomid bats. Both are frugivorous and frequently found coexisting in the same areas. A study on feeding habits and morphology of C. perspicillata and S. lilium was conducted at Serra do Japi, Sấo Paulo, south-eastern Brazil, investigating the mechanisms associated with their coexistence. The two species are fairly similar in morphology and feeding habits. Analysis of faeces produced by captured bats revealed that there is a significant difference in diet between the two species. C. perspicillata tends to specialize in fruits of the genus Piper and S. lilium specializes in Solarium fruits. The fruiting periods of the four species of Piper eaten by bats at the study site are successive, with little overlap and high productivity. The species of Solarium have long and overlapping fruiting periods, with very low productivity. Piper and Solarium provide food resources almost all year, allowing the food specialization that may be an important mechanism of resource partitioning between C. perspicillata and S. lilium.
Herbivory as an ecological process in a Kandelia candel (Rhizophoraceae) mangal in Hong Kong
Authors: Lee S. Y.
Published: July 2009

Natural levels and consequences of insect herbivory were studied for a Kandelia candel (Rhizophoraceae) dominated mangal at the Mai Po Marshes, Hong Kong. Grazing insects (mainly lepidopteran larvae) consumed, on average, 10.3% of the leaf area on K. candel, with >90% of the leaves suffering <30% loss. Natural median leaf longevity was significantly different between winter and summer-exposed leaves, being, respectively, 423.2 and 269.6 days. Observations showed that herbivore damage caused a reduction of leaf longevity, as severely damaged leaves were abscissed before intact, older leaves on the same branch. Experimental leaf area removal suggested that leaf life span reduction was significantly influenced by leaf age and degree of damage. However, the reduction was only significant (>40 days) when area loss was >40%. Leaves produced in summer were also more sensitive to damage than those produced in winter. As <5% of the leaves suffered >40% of area removal by insect grazing in nature, insect herbivory is considered an unimportant regulator of leaf litter dynamics for K. candel. At this intensity level, herbivory consumes 2.8–3.5% of the net above-ground primary production of the mangrove. There was also no significant difference in the final number of leaves and twigs produced by the branches with various degrees of leaf area removal. Other observed impacts of insects on the structure and function of the K. candel mangal are discussed.
Above-ground phytomass of a tropical deciduous forest on the coast of Jalisco, México
Authors: Martinez-Yrizar Angelina , Sarukhan Jose , Perez-Jimenez Alfredo , Rincon Emmanuel , Maass Jose Manuel , Solis-Magallanes Arturo , Cervantes Luis
Published: July 2009

Phytomass was determined for a tropical deciduous forest in Chamela, Jalisco, México. The mean canopy height was 6.9 m, and the total basal area was 25.6 m2ha−1(dbh > 3.0 cm). The estimated phytomass for this forest (85 Mg ha−1) is among the highest values for tropical dry forests with similar seasonal climates. A stepwise multiple regression analysis showed that phytomass can be predicted firstly by basal area (R2= 0.88), then by wood specific gravity (R2= 0.91), and finally by the inclusion of tree height in the regression (R2= 0.92). Each new independent variable explained significant variance in the phytomass estimation.
Patterns of forest diversity along the Tana River, Kenya
Authors: Medley Kimberly E.
Published: July 2009

Tropical forest vegetation occurs within a narrow corridor along the semi-arid lower floodplain of the Tana River, Kenya. An inventory of the woody flora and ecological study of 12 forest areas in the Tana River National Primate Reserve (TRNPR) describe the composition and structure of this riverine forest ecosystem and identify patterns of regional and local diversity. Only 175 species in 49 families are recorded in the woody flora, but the geographic affinities of 98 species are from four major floristic regions in Africa: Zanzibar-Inhambane (31%), Somalia-Masai (16%), Guinea-Congolian (12%), and Zambezian (1%). Ten species are rare and/or disjunct. Forests have a disturbed physiognomy characterized by a low mean height (14.4 m), high species importance attributable to a few trees, low density (409 ha−1) and coverage (23.1 m2 ha−1) of trees > 10 cm dbh, and an abundance of palms and lianes. Changes along the river in sediment deposition and hydrology explain the high diversity of landforms and corresponding forest types in the TRNPR vicinity, but the absence of trees which are most important near Bura, Acacia elalior, and near Wema, Barringtonia racemosa, suggests that the regional diversity of the ecosystem is inadequately protected. Preservation of key resources, such as the endangered primates, should be coupled with protection of the forest heterogeneity that characterizes this dynamic landscape.
Transfer of macro-nutrients to the atmosphere during experimental burnings in an open cerrado (Brazilian savanna)
Authors: Pivello Vania R. , Coutinho Leopoldo M.
Published: July 2009

This paper presents the quantities of macro-nutrients (N, P, K, Ca, Mg and S) released from the ground layer vegetation to the atmosphere during six experimental burnings, in a Brazilian open savanna, named ‘campo-cerrado’. The values were obtained by comparing the amounts of nutrients in the fuel and in the ash resulting after the burn, in three different seasons. On average, 20.6 kg of N, 1.6kg of P, 7.1 kg of K, 12.1kg of Ca, 3.0 kg of Mg, and 3.2kg of S ha−1 were transferred from the plant biomass to the atmosphere, representing mean percentages of 95% for N, 51% for P, 44% for K, 52% for Ca, 42% for Mg, and 59% for S. The burn season showed no significant influence on the amounts of nutrients transferred to the atmosphere. Some relationships involving the quantities of macro-nutrients released, fuel moisture, the combustion efficiency during the burns, and the initial standing biomass in the area were also tested. Comparing the average output of macro-nutrients to the atmosphere obtained in this study with their inputs via rainfall, in the same area, it was estimated that three years would be an adequate interval between prescribed burnings for this campo-cerrado, to speed up nutrient recycling without impoverishing the system.
Reproductive biology of two species of Kielmeyera (Guttiferae) in the cerrados of Central Brazil
Authors: Oliveira Paulo E. , Silva Jose C. S.
Published: July 2009

The reproductive process of two species of Kielmeyera, K. coriacea and K. speciosa, sympatric in savanna areas in central Brazil, has been studied. The trees have similar pollination systems and dispersal mechanisms but distinct phenological behaviours. Fast germination after the beginning of the wet season, early root swelling forming a xylopodium which enables survival during the dry season, and recurrent sprouting from the swollen root system during the first years of development were features of an establishment syndrome common to both species. The seedling survival after establishment was high; after five years 64% of the seedling cohort of K. coriacea was still alive. These seedlings, in natural conditions, remain poorly developed and resprout recurrently from the soil during some years. The recruitment of adult plants seems to occur from this ‘seedling bank’. The reproductive process was higher in K. coriacea during most stages of the reproductive process which may explain the smaller population size and distribution range of K. speciosa. For both species, the reproductive process as a whole was mainly affected by biotic factors in the wet season and not by seasonal drought or periodic fire.
Ant-tended scale insects (Hemiptera: Coccidae:Myzolecanium) within lowland rain forest trees in Papua New Guinea
Authors: Gullan Penny J. , Buckley Ralf C. , Ward Philip S.
Published: July 2009

Eight species ofMyzolecaniumBeccari (Hemiptera: Homoptera: Coccoidea: Coccidae) are reported from ant nests in stem cavities of living lowland rain forest trees in Papua New Guinea. The coccids are confined to this microhabitat but are associated with a taxonomically broad range of ants and host trees. Attendant ants belonged to six species in three genera and two subfamilies:AnonychomyrmaDonisthorpe (Dolichoderinae),CrematogasterLund (Myrmicinae) andPodomyrmaF. Smith (Myrmicinae). Host plants belonged to at least five families and included both apparently specialized (with domatia) and unspecialized species. Saplings containing the nests ofAnonychomyrma scrutator(F. Smith),Anonychomyrmasp. 1 andPodomyrma laevifronsF. Smith were dissected and the structure of nest chambers and their contents recorded. Only some chambers had entrance holes, but many were interconnected by transverse passages. The coccids were in low numbers and fairly evenly distributed between ant-occupied chambers. The characteristics of theMyzolecanium-ant association, the role of the coccids as trophobionts, and the nature of the plant associations are discussed. Taxonomically, new combinations are proposed by P. J. Gullan for three species previously placed inCryptostigmaFerris:Myzolecanium endoeucalyptus(Qin & Gullan),M. magnetinsulae(Qin & Gullan), andM. robertsi(Williams & Watson).
Spatial and temporal components of species diversity in Auchenorrhyncha (Insecta: Hemiptera) communities of Indochinese montane rain forest
Authors: Novotný Vojtěch
Published: July 2009

The Auchenorrhyncha community within the understorey of a montane monsoon rain forest in Vietnam is described. It was highly diverse, with 328 morphospecies in a sample of 1611 specimens. The community was variable in species composition with respect to space (between sites 1–5 km distant) and time (between early and late wet seasons). Differences in species composition attributable to spatial heterogeneity and to seasonal variation were of a comparable magnitude when examined by the CCA ordination. Auchenorrhyncha density, estimated by sweeping, was generally low, at 1 to 2 individuals m−3 of vegetation. There was a negative correlation between the species' population size in the early and the late wet seasons.
The implications of climate and gap microclimate for seedling growth conditions in a Bornean lowland rain forest
Authors: Brown Nick
Published: July 2009

Present theories of tropical rain forest regeneration dynamics suggest that different tree species specialize on the microclimates of different sizes of canopy gap. A detailed analysis of the microclimates of closed forest and 10 canopy gaps of different sizes was carried out in lowland dipterocarp rain forest, Sabah, Malaysian Borneo. It reveals that gaps exhibit considerable spatial and temporal variation in microclimate. As a consequence the relationship between microclimate and gap sizes is not simple. Gaps of the same size do not necessarily have the same microclimate and may favour the growth of different seedling species. Chance location and timing of gap creation play an important role in regeneration dynamics.
A comparative study of cerrado (sensu stricto) vegetation in Central Brazil
Authors: Felfili Jeanine Maria , da Silva Manoel Claudio
Published: July 2009

Floristic and structural comparisons and a numerical classification were performed to identify the priority areas for conservation of genetic resources in central Brazil. The main type of woody vegetation, cerrado sensu stricto (savanna woodland with 10–60% tree cover), was sampled under a uniform methodology in six selected sites (total sample of 6 ha) scattered in a physiographic unit called the Pratinha Plateau located between 15–20° S and 46–49° W. A total of 6971 trees belonging to 139 species and 42 families was measured. Each site had a combination of 50–80 species and approximately 30 families but only 22 species from 14 families were common to all sites. Similarity decreased with distance, indicating the existence of geographical gradients as the physical characteristics were relatively uniform and the soils were dystrophic at all sites. The most dissimilar sites, in the localities of Patrocínio-MG and Paracatu-MG were recommended for the establishment of conservation units. The already existent conservation units arc all clumped in the Federal District and are not enough to protect the genetic heritage of the plateau. Floristics and phytosociological surveys based on land system zoning were recommended as useful tools in planning conservation areas at a regional level to preserve the maximum biodiversity.
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

Air 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

Descriptions 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

The 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

The 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

Plots 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

Patterns 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

The 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

The 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

A 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

Spiders 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

This 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

We 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

Analysis 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

The 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

White-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

A 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

Introduced 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

Effects 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.
Do elephants over-utilize mopane woodlands in northern Botswana?
Authors: Ben-Shahar Raphael
Published: July 2009

Evidence from southern African semi-arid savannas suggests that high elephant densities in nature reserves cause the over-utilization of woodlands. Northern Botswana, with its prolific elephant population, is expected to follow such a pattern unless the densities of elephants which could be sustained by indigenous woodlands are determined and maintained at carrying capacity. Above ground biomass production was estimated for mopane (Colophospermum mopane) woodlands, a principal food source for elephants, which grows over much of northern Botswana. Densities of trees and shrubs, dimensions of plants and elephant densities were recorded within stratified plots situated according to a regional rainfall gradient. Mean estimates of above ground biomass (foliage and twigs) were 9.41 and 7.83 t ha−1 for shrubs and trees respectively. A logistic model described the maximum levels of biomass removal from plants before over-utilization of mopane occurred. Variables incorporated in the model included above ground biomass of mopane shrubs and trees, growth rates of plants and expected off-take by elephants. The model predicted a complete biomass regain within 10 y if no elephant browsing occurs. Intensive elephant browsing in woodlands containing 15 elephants km−2, however, can suppress biomass production if growth rates of plants fall below 70% of the maximum annual rate. Nonetheless, there was no substantial evidence to suggest that elephants will reduce the biomass of mopane woodlands in northern Botswana below a sustainable level if their numbers are allowed to increase considerably beyond the current estimate.
Seed viability of Afromontane tree species in forest soils
Authors: Teketay Demel , Granström Anders
Published: July 2009

The fate of seeds of eight tree species was followed during 4 y of storage in the soil of an Afromontane forest at Gara Ades in the eastern highlands of Ethiopia. Seeds were enclosed in nylon mesh bags and buried at 5 cm soil depth. The bags were exhumed at intervals and the viability of the seeds was assessed by germination and cutting tests. Seeds ofBersama abyssinicaandEkebergia capensisgerminated in the soil almost completely within a year after burial. The seeds ofJuniperus procera, Olea europaeaandPodocarpus falcatusalso germinated to a substantial degree in the soil but with a distribution over several years, and some seeds of these species remained viable at the end of the 4-y period. Germination in the soil was very low in seeds ofAcacia abyssinicaandCroton macrostachyusthroughout the whole burial period and the seeds kept their viability. InC. macrostachyusfresh seeds were highly dormant, but after 3 y or more in the soil they germinated readily in the laboratory suggesting an altered dormancy with time in the soil. Dormancy in seeds ofA. abyssinicaandIndigofera rothiiwas not altered throughout the study period as evidenced by marginal or no germination during incubation in the laboratory. The differential seed behaviour observed during storage in the soil can be an indicator of the regeneration strategy of the species studied.B. abyssinica, E. capensis, J. procera, O. europaeaandP. falcatusform seedling banks on the forest floor and lack persistent soil seed reserves in contrast toA. abyssinica, C. macrostachyusandI. rothiiwhich accumulate reserves of long-lived seeds in the soil. The generally high levels of dormancy and somewhat extended viability in the soil, even in several of the species producing seedlings in undisturbed forest, may have been selected for under a climate of seasonal drought and unreliable rainfall that characterizes this region.
Altitudinal zonation of rain forest on Bukit Belalong, Brunei: soils, forest structure and floristics
Authors: Pendry Colin A. , Proctor John
Published: July 2009

Bukit Belalong, Brunei, is a small mountain (913 m) of uniform shale lithology with continuous primary rain forest from its base to its summit. Three 0.25 ha plots were established at each of three altitudes (200, 500 and 850 m) to investigate the altitudinal zonation of the soils and the vegetation. One soil profile from each altitude is described and chemical analyses of the soils indicate that they are similar at all altitudes. In each plot all trees ≥10 cm dbh were measured and identified as far as possible. Maximum tree height was greatest at 200 m (60 m) and least at 850 m (33 m). Tree density (number of individuals ha−1) increased with altitude. The forest at 850 m was the most species- and family-rich, but since the ratio of species to individuals did not vary significantly among altitudes, the higher species richness is attributed partly to the larger number of trees sampled. The Dipterocarpaceae was the most important family in terms of basal area at all altitudes, but its proportion of basal area was much smaller at 850 m than at the other altitudes. The Dipterocarpaceae was the most diverse family at 200 m and 500 m, but at 850 m its diversity was exceeded by the Lauraceae, Myrtaceae and Euphorbiaceae and equalled by the Clusiaceae. The forests at 200 m and 500 m are classified as lowland rain forest and that at 850 m is classified as a lower montane forest.
Seed predation in a tropical mangrove forest: a test of the dominance-predation model in northern Australia
Authors: McGuinness Keith A.
Published: July 2009

Studies of predation on propagules of the mangroves Avicennia marina, Bruguiera exaristata, Ceriops tagal and Rhizophora stylosa were made in a forest in northern Australia to test the generality of the dominance-predation model. This model states that an inverse relationship exists between the dominance of a species in the canopy of mangrove forests and the rate of predation on the propagules of that species. Significant differences in predation were found among the four species, and among patches of forest dominated by the different species. Predators attacked more than 50% of the propagules of all species except R. stylosa, so are likely to significantly affect forest structure. The intensity of predation did not, however, vary as the dominance-predation model predicted. Instead, predation on the propagules of a species appeared to depend on the availability of propagules of other, more highly preferred, species.
Reproductive allocation and pollinator distributions in cauliflorus trees in Trinidad
Authors: Warren John M. , Emamdie Debbie Z. , Kalai
Published: July 2009

Little information is available to test the various theories which have been proposed to explain the evolution of cauliflory. This study provides such data from observations in Trinidad of the numbers of potential pollinators visiting trunk and canopy flowers and on the size of canopy and trunk flowers and fruits. Subsidiary observations were made on the partitioning of resources between the sexes within flowers. Significantly more potential insect pollinators were trapped around the trunk flowers of two cauliflorous species than were caught around their canopy flowers. Trunk flowers were found to be larger than canopy flowers in four of the seven cauliflorous species studied, but they were smaller in one species. The higher probability of fruit set on trunks than in the canopy may have selected for cauliflory and subsequently increased trunk flower size in insect-pollinated understorey tropical trees. There was a tendency for flowers on the trunk not only to be larger but also to allocate relatively more dry weight to female parts and result in larger fruit than those in the canopy. These observations are consistent with Wallace's theory of the evolution of cauliflory, which argues that the condition arose in the dark understorey of the tropical forest, as a result of selection for trunk flowers which are more apparent to pollinators than are canopy flowers. However, other explanations for the evolution of cauliflory are not precluded as they are not mutually exclusive.
Mass and nutrient dynamics of decaying litter fromPassiflora mollissimaand selected native species in a Hawaiian montane rain forest
Authors: Scowcroft Paul G.
Published: July 2009

The structure and functioning ofAcacia koa-Metrosideros polymorphaforests between 1200 and 1800 m elevation on the island of Hawaii are being threatened byPassiflora mollissima, an aggressive introduced liana from South America. This study was done to evaluate the short-term decomposition dynamics ofPassifloraand selected native leaf and twig litter. The nutrient-rich, non-sclerophyllousPassifloraleaves completely disappeared in less than 5 mo. The estimated time for native leaf litter to lose 95% of initial dry weight ranged from 1.65 y for N-richAcaciaphyllodes to 6.67 y forCibotium glaucum; for woody litter, the time ranged from 4.5 y forAcaciatwigs to 23 y forAcaciabark. Except forCibotiumfrond litter, decay rates were significantly correlated with initial lignin-ash ratios.Passifloralitter did not accelerate decomposition ofAcaciaandMetrosiderosleaf litter.Passiflora, Acacia, andMetrosiderosleaf litter showed net mineralization of N, P, Ca, K, and Mg during the study.Cibotiumfrond litter showed significant accumulation of N, Ca, and Mg; P levels stayed constant and K was rapidly lost. In general, twigs experienced a net loss of most nutrients, while bark experienced either no change or a significant net gain of nutrients. Nutrient cycling has increased inP. mollissimainfested forests.
The distribution of organic carbon in major components of forests located in five life zones of Venezuela
Authors: Delaney M. , Brown S. , Lugo A. E. , Torres-Lezama A. , Quintero N. Bello
Published: July 2009

One of the major uncertainties concerning the role of tropical forests in the global carbon cycle is the lack of adequate data on the carbon content of all their components. The goal of this study was to contribute to filling this data gap by estimating the quantity of carbon in the biomass, soil and necromass for 23 long-term permanent forest plots in five life zones of Venezuela to determine how C was partitioned among these components across a range of environments. Aboveground biomass C ranged from 70 to 179 Mg ha−1and soil C from 125 to 257 Mg ha−1, and they represented the two largest C components in all plots. The C in fine litter (2.4 to 5.2 Mg ha−1), dead wood (2.4 to 21.2 Mg ha−1) and roots (23.6 to 38.0 Mg ha−1) accounted for less than 13% of the total C. The total amount of C among life zones ranged from 302 to 488 Mg ha−1, and showed no clear trend with life zone. In three of the five life zones, more C was found in the dead (soil, litter, dead wood) than in the live (biomass) components (dead to live ratios of 1.3 to 2.3); the lowland moist and moist transition to dry life zones had dead to live ratios of less than one. Results from this research suggest that for most life zones, an amount equivalent to between 20 and 58% of the aboveground biomass is located in necromass and roots. These percentages coupled with reliable estimates of aboveground biomass from forest inventories enable a more complete estimation of the C content of tropical forests to be made.