bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tropical secondary forests
Authors: Brown Sandra , Lugo Ariel E. 
Published: July 2009

ABSTRACTThe literature on tropical secondary forests, defined as those resulting from human disturbance (e.g. logged forests and forest fallows), is reviewed to address questions related to their extent, rates of formation, ecological characteristics, values and uses to humans, and potential for management. Secondary forests are extensive in the tropics, accounting for about 40% of the total forest area and their rates of formation are about 9 million ha yr−1. Geographical differences in the extent, rates of formation and types of forest being converted exist.Secondary forests appear to accumulate woody plant species at a relatively rapid rate but the mechanisms involved are complex and no clear pattern emerged. Compared to mature forests, the structure of secondary forest vegetation is simple, although age, climate and soil type are modifying factors. Biomass accumulates rapidly in secondary forests, up to 100 t ha−1during the first 15 yr or so, but history of disturbance may modify this trend. Like biomass, high rates of litter production are established relatively quickly, up to 12–13 t ha−1yr−1by age 12–15 yr. And, in younger secondary forests (< 20 yr), litter production is a higher fraction of the net primary productivity than stemwood biomass production. More organic matter is pro duced and transferred to the soil in younger secondary forests than is stored in above-ground vegetation. The impact of this on soil organic matter is significant and explains why the recovery of organic matter in the soil under secondary forests is relatively fast (50 yr or so). Nutrients are accumulated rapidly in secondary vegetation, and are returned quickly by litterfall and decomposition for uptake by roots.We propose a model of the gains and losses, yields and costs, and benefits and tradeoffs to people from the current land-use changes occurring in the tropics. When the conversion of forest lands to secondary forests and agriculture is too fast or land-use stages are skipped, society loses goods and services. To avoid such a loss, we advocate management of tropical forest lands within a landscape perspective, a possibility in the tropics because land tenures and development projects are often large.
Ecology of the Asian elephant in southern India. II. Feeding habits and crop raiding patterns
Authors: Sukumar R. 
Published: July 2009

ABSTRACTThe Asian elephant's foraging strategy in its natural habitat and in cultivation was studied in southern India during 1981–83. Though elephants consumed at least 112 plant species in the study area, about 85% of their diet consisted of only 25 species from the order Malvales and the families Leguminosae, Palmae, Cyperaceae and Gramineae. Alteration between a predominantly browse diet during the dry season with a grass diet during the early wet season was related to the seasonally changing protein content of grasses.Crop raiding, which was sporadic during the dry season, gradually increased with more area being cultivated with the onset of rains. Raiding frequency reached a peak during October-December, with some villages being raided almost every night, when finger millet (Eleusine coracana) was cultivated by most farmers. The monthly frequency of raiding was related to the seasonal movement of elephant herds and to the size of the enclave. Of their total annual food requirement, adult bull elephants derived an estimated 9.3% and family herds 1.7% in quantity from cultivated land. Cultivated cereal and millet crops provided significantly more protein, calcium and sodium than the wild grasses. Ultimately, crop raiding can be thought of as an extension of the elephant's optimal foraging strategy.
Flora and reproductive phenology of the rain forest at Bukit Timah, Singapore
Authors: Corlett Richard T. 
Published: July 2009

ABSTRACTThe 71 ha Bukit Timah Nature Reserve contains the largest surviving area of primary rain forest in Singapore. The recorded vascular plant flora of the forest consists of at least 854 species: 787 angiosperms in 109 families, 65 pteridophytes and three gymnosperms. 58.6% of the species are trees or shrubs, 18.7% climbers, 12.3% terrestrial herbs, 8.8% epiphytes and hemi-epiphytes, 1.0% saprophytes and 0.6% parasites. The four families with most species -Rubiaceae, Euphorbiaceae, Orchidaceae and Moraceae - account for a quarter of the angio-sperm flora but contribute few large trees. Community reproductive phenology is charac-terized by supra-annual bursts of general flowering and fruiting, contrasting with a low back-ground level. After an exceptionally dry and sunny February, 1987, more than 150 species in 42 families flowered between late March and late May, followed by an equally well-defined fruiting peak 13 weeks later, between late June and late August.
Nitrogenase activity in soil and litter of a tropical lowland rain forest and an adjacent fernland in Sri Lanka
Authors: Maheswaran J. , Gunatilleke I. A. U. N. 
Published: July 2009

ABSTRACTNitrogenase activity in the surface soil and litter layers from a tropical lowland rain forest and an adjacent fernland in Sri Lanka was measured by the acetylene reduction method. The total amount of acetylene reduced, a measure of biological nitrogen fixation, was greater in the fernland (38.4 µmol m−2 h−1) than in the forest (15.3–29.2 µmol m−2 h−1). In both ecosystems the nitrogenase activity was greater (59–85%) in the soil than in the litter layer. The rates of acetylene reduction in soil and litter showed an inverse relationship with the decay constants of mixed litter and a positive relationship was found between the rate of acetylene reduction and the C:extractable nitrogen ratio of the soil. The relatively greater rate of nitro genase activity coupled with the slower rate of litter decomposition in the fernland indicates that accumulation of nitrogen may result in the soil and litter layers of the deforested areas during their aggrading phases.
Termites, soil fertility and carbon cycling in dry tropical Africa: a hypothesis
Authors: Jones Julia Allen 
Published: July 2009

ABSTRACTTermites, particularly the mound building, fungus growing Macrotermitinae, reach densities of up to 400 termites m−2in soils of dry tropical Africa. The influence of Macrotermi tinae in increasing certain soil nutrients in mounds compared to adjacent soils has been documented, but the links between litter harvesting by termites, soil fertility, and global C cycling have not been explored. This study reviews the evidence from soil science, ecology and atmos pheric chemistry and generates hypotheses to explain the role of termites in dry tropical eco systems. It is suggested that termite activity exhaustively partitions litterfall among adjacent com peting colonies, where it is so thoroughly decomposed that little or no organic C is incorporated into the soils. Associated N, P, and cations build up in the mounds, but C apparently is emitted as CO2and CH4from the mounds. While not adequate to calculate nutrient fluxes through termites, the data available support the argument that termites contribute significantly to atmospheric fluxes of CO2and CH4. Moreover, they suggest a coupling of regional soil forming processes and the global C budget.
The influence of primary production on a raptor community in Hwange National Park, Zimbabwe
Authors: Hustler K. , Howells W. W. 
Published: July 2009

ABSTRACTWe studied the breeding success and distribution of three species of eagles, four species of vultures and one species of eagle owl on two areas of differing primary productivity from 1973 to 1984. Densities of all species were lower in areas with lower productivity. Breed-ing success on both biomes was similar, the lower densities of birds on the least productive biome apparently compensating for the lower productivity. Eagles produced more one-egg clutches, laid later and reared fewer young in the period of poor rainfall, probably as a result of reduced productivity. Vulture data were difficult to interpret because abundant food at breed-ing time was created by ungulate population management throughout the entire study period. Concentrations of all species on the more productive biome, and solitary breeding on the least productive biome by a normally colonially breeding species, suggests that primary production also influences vulture densities and perhaps breeding success.
The biosystematics and evolution of thePolyalthia hypoleucaspecies complex (Annonaceae) of Malesia. II. Comparative distributional ecology
Authors: Rogstad Steven H. 
Published: July 2009

ABSTRACTOne component of the high organismal diversity of tropical lowland rain forests is the existence of series of closely related, sympatric species. For example, the six distinct tree species of the monophyleticPolyalthia hypoleucacomplex regularly grow sympatrically in various combinations throughout the rain forests of Malesia. Theoretical and empirical evidence has been presented indicating that the members of such series either (1) are well differentiated with respect to at least one major niche component; or (2) may lack differentiated niches. In this study, certain sympatric members of the complex are shown to have clearly diverged in autecological characteristics that affect their distribution including: (1)P. glauca, P. hypoleuca, andP. sumatranadiffer in growth characteristics, height at maturity, seedling germination requirements, and are found on soils with differing degrees of hydration; (2)P. discolorgrows to a different height and on different substrate types than doesP. multinervis; and (3)P. glaucaandP. hypoleucaseedlings differ in transpiration characteristics and response to flooding and drought.
Seed-dispersal ofVouacapoua americana(Caesalpiniaceae) by caviomorph rodents in French Guiana
Authors: Forget Pierre-Michel 
Published: July 2009

ABSTRACTA 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

ABSTRACTCarollia 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

ABSTRACTNatural 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

ABSTRACTPhytomass 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 &gt; 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

ABSTRACTTropical 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

ABSTRACTThis 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

ABSTRACTThe 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

ABSTRACTEight 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

ABSTRACTThe 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

ABSTRACTPresent 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

ABSTRACTFloristic 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.