Effects of Selective Logging on Bat Communities in the Southeastern Amazon

Abstract:  Although extensive areas of tropical forest are selectively logged each year, the responses of bat communities to this form of disturbance have rarely been examined. Our objectives were to (1) compare bat abundance, species composition, and feeding guild structure between unlogged and low-intensity selectively logged (1–4 logged stems/ha) sampling grids in the southeastern Amazon and (2) examine correlations between logging-induced changes in bat communities and forest structure. We captured bats in understory and canopy mist nets set in five 1-ha study grids in both logged and unlogged forest. We captured 996 individuals, representing 5 families, 32 genera, and 49 species. Abundances of nectarivorous and frugivorous taxa (Glossophaginae, Lonchophyllinae, Stenodermatinae, and Carolliinae) were higher at logged sites, where canopy openness and understory foliage density were greatest. In contrast, insectivorous and omnivorous species (Emballonuridae, Mormoopidae, Phyllostominae, and Vespertilionidae) were more abundant in unlogged sites, where canopy foliage density and variability in the understory stratum were greatest. Multivariate analyses indicated that understory bat species composition differed strongly between logged and unlogged sites but provided little evidence of logging effects for the canopy fauna. Different responses among feeding guilds and taxonomic groups appeared to be related to foraging and echolocation strategies and to changes in canopy cover and understory foliage densities. Our results suggest that even low-intensity logging modifies habitat structure, leading to changes in bat species composition.     

Inhibition of Amazon Deforestation and Fire by Parks and Indigenous Lands

Abstract:  Conservation scientists generally agree that many types of protected areas will be needed to protect tropical forests. But little is known of the comparative performance of inhabited and uninhabited reserves in slowing the most extreme form of forest disturbance: conversion to agriculture. We used satellite-based maps of land cover and fire occurrence in the Brazilian Amazon to compare the performance of large (>10,000 ha) uninhabited (parks) and inhabited (indigenous lands, extractive reserves, and national forests) reserves. Reserves significantly reduced both deforestation and fire. Deforestation was 1.7 (extractive reserves) to 20 (parks) times higher along the outside versus the inside of the reserve perimeters and fire occurrence was 4 (indigenous lands) to 9 (national forests) times higher. No strong difference in the inhibition of deforestation ( p = 0.11) or fire ( p = 0.34) was found between parks and indigenous lands. However, uninhabited reserves tended to be located away from areas of high deforestation and burning rates. In contrast, indigenous lands were often created in response to frontier expansion, and many prevented deforestation completely despite high rates of deforestation along their boundaries. The inhibitory effect of indigenous lands on deforestation was strong after centuries of contact with the national society and was not correlated with indigenous population density. Indigenous lands occupy one-fifth of the Brazilian Amazon—five times the area under protection in parks—and are currently the most important barrier to Amazon deforestation. As the protected-area network expands from 36% to 41% of the Brazilian Amazon over the coming years, the greatest challenge will be successful reserve implementation in high-risk areas of frontier expansion as indigenous lands are strengthened. This success will depend on a broad base of political support.     

Changing Drivers of Deforestation and New Opportunities for Conservation

Abstract: Over the past 50 years, human agents of deforestation have changed in ways that have potentially important implications for conservation efforts. We characterized these changes through a meta‐analysis of case studies of land‐cover change in the tropics. From the 1960s to the 1980s, small‐scale farmers, with state assistance, deforested large areas of tropical forest in Southeast Asia and Latin America. As globalization and urbanization increased during the 1980s, the agents of deforestation changed in two important parts of the tropical biome, the lowland rainforests in Brazil and Indonesia. Well‐capitalized ranchers, farmers, and loggers producing for consumers in distant markets became more prominent in these places and this globalization weakened the historically strong relationship between local population growth and forest cover. At the same time, forests have begun to regrow in some tropical uplands. These changing circumstances, we believe, suggest two new and differing strategies for biodiversity conservation in the tropics, one focused on conserving uplands and the other on promoting environmental stewardship in lowlands and other areas conducive to industrial agriculture.     

热带胶园土壤磷素形态和生物有效性

采用Hedley的磷素分级方法研究热带胶园土壤磷的形态,结果表明、热带胶园土壤磷主要以ResidualP、NaOH－Po和NaOH－Pi形态存在;各种形态磷的损失质量分数均高于38％;其中ResidualP和NaOH－Po的损失量最高,分别占全磷损失量的52％和16％,它们是长期耕作条件下热带胶园土壤磷两种最重要的有效磷源。     

The Response of Avian Feeding Guilds to Tropical Forest Disturbance

Abstract:  Anthropogenic habitat disturbance is a major threat to tropical forests and understanding the ecological consequences of this disturbance is crucial for the conservation of biodiversity. There have been many attempts to determine the ecological traits associated with bird species' vulnerability to disturbance, but no attempt has been made to synthesize these studies to show consensus. We analyzed data from 57 published studies (covering 1214 bird species) that investigated the response of tropical bird assemblages to moderate forest disturbance (e.g., selective logging). Our results show that the mean abundance of species from six commonly reported feeding guilds responded differently to disturbance and that species' ecological traits (body size, local population size, and geographic range size) and evolutionary relationships may influence responses in some guilds. Granivore abundance increased significantly and insectivore and frugivore abundance decreased significantly following disturbance. These general conclusions were robust to the effects of ecological traits and phylogeny. Responses of carnivores, nectarivores, and omnivores were less clear, but analyses that accounted for phylogeny indicated that these guilds declined following disturbance. In contrast to the other guilds, the reported responses of carnivores and nectarivores differed among regions (Asia vs. Neotropics) and were influenced by the sampling protocols used in different studies (e.g., time since disturbance), which may explain the difficulty in detecting general responses to disturbance in these guilds. Overall, general patterns governed the responses of species to habitat disturbance, and the differential responses of guilds suggested that disturbance affects trophic organization and thus ecosystem functioning.     

Nutrients in soil solution following selective logging of a humid tropical ‘terra firme’ forest north of Manaus,Brazil

Sustainable use of the Amazon forest for timber production is conditioned by the effect of logging on the system's nutrient cycling. This paper reports the results of a soil moisture and soil water chemistry monitoring campaign before and immediately after a selective logging which removed 35 m³ wood/ha. Soil moisture was measured using tensiometers, and soil water chemistry using suction samplers in five disturbance classes: tractor tracks, clearing centres, clearing edges, forest edges and untouched forest. The results show that the soil under the tractor tracks and clearings contained more moisture than under the untouched forest. The suction samplers extracted substantially more nitrate, ammonium, calcium, magnesium and potassium from the clearing centres, the tractor tracks and the clearing edges than from the forest sites. The results are explained in terms of altered microbial activity, changes in crown interception and uptake by roots.     

Environmental implications of tropical deforestation

SUMMARY

Forests are fundamental and vital components of the world ecosystems. The essential links between forest and man are now receiving renewed and urgent attention, and there is increasing awareness that the value of forests to life on Earth is beyond economic value, and should be above political considerations. Tropical forests, generally marked out by richness in species, are found in more than 80 countries and account for roughly one-third of the world's forest cover. They encompass a wide variety of forest types found under diverse environmental conditions — from lush, constantly wet rain forests to arid thorn woodlands. These forests have been estimated to cover about 1715 million hectares in Africa alone. They have provided habitats for wildlife and wood, fibre, food and many other products to generations of mankind and are invaluable genetic resources of plants. Rapid population growth has, however, resulted in increasing the pressure on these forests, with a consequent decline in their qualitative and quantitative values. Throughout the world, forest lands have been cleared extensively for agriculture, and deforestation continues today. In the tropics, 10–25 million ha are being lost each year, with Africa alone losing 4–5 million ha annually. It has been estimated that, at this rate, the remaining tropical forest would disappear in 60–80 years; thereby leading to catastrophic environmental changes. The serious impact of these changes on the environment and on human needs is awakening world attention, and alarming consequences have sometimes been suggested. This paper highlights the major causes of tropical deforestation and its environmental consequences. Possible efforts to arrest the unpleasant trend are discussed.     

Organochlorine pesticide in water and bottom sediment from Aiba Reservoir (Southwestern Nigeria)

Levels of organochlorine pesticides (OCPs) in water and sediment from Aiba reservoir (Southwestern Nigeria) have been assessed. The aim of the study was to investigate the pollution status of the reservoir water and the bottom sediment. Analytical measurements were carried out for 20 OCPs using standard literature methods. The results showed higher levels of OCPs in the bottom sediment than the water. Significant positive correlations at p<0.05 level were observed for OCPs compounds in water except γ-BHC and endosulfan III, whereas in sediments α-chlordane, dieldrin, endosulfan II, pp-DDT, endrin ketone and methoxychlor did not show any correlation, and aldrin was negatively correlated with pp-DDD. The mean levels of OCPs in both water and sediments were higher, in most cases, than recommended levels for drinking water. Owing to possible toxicity and bioaccumulation tendency of OCPs by the aquatic habitats, the levels of OCPs detected in water and sediment samples could be a source of future health problems. Environmental monitoring of the reservoir is highly recommended.     

Dose Dependent Interactions Between Ammonification Potential and Bacteria in Three Tropical Pond Ecosystems

Using six different doses of peptone (0.25, 0.50, 0.75, 1.0, 1.25 and 1.50 gl^-1) and nine different periods of inclubation (1, 2, 3, 4, 6, 8, 10, 12 and 14 days), the rates of ammonification potential (AP) were monitored in three tropical ponds of differetn ecological status, during winter and summer periods. During the winter, the AP (ammonifying bacteria) exhibited peaks on day 4 of incubation in all the test doses of peptone in all the three ponds, except in the lowest dose in eutrophic and chemically polluted pond where the peaks preceded by a day. the responses of AP to the lowest doses of substrate did not differ between summer and winter, while the AP-peaks at higher doses were delayed by 2 days in summer. the concentrations of nitrate in vitro were the inverse and direct functions of the AP and dissolved oxygen of water. at moderate dose (0.75 gl^-1) of peptone, both AP and dissolved oxygen at higher doses, and by AP at the lowest dose of peptone.     

西双版纳补蚌地区望天树林近20 a来物种多样性变化研究

通过对1988年和2006年西双版纳补蚌地区望天树林样方资料的比较研究,探讨了望天树林群落近20a来在物种多样性方面的变化.研究结果表明,在2006年的样方中,望天树仍然具有最大的优势度,该群落仍然是以望天树为优势种的单优群落.在群落自身演替以及外界环境干扰的影响下,幼树、灌木和藤本植物种类和数量明显增加,而草本植物和附生植物减少.分析乔木层的物种多样性变化发现,尽管2006年样方在植物种类和数量上都要高于1988年样方,但辛普森指数和均匀度指数并未增加,很可能是样方中形成了林窗的结果.另外,乔木层中物种优势度变化非常明显,少数优势种衰退了,少数变得更优势.1988年的两个样方中分别有50%和40%的物种被后来的物种所取代,物种替换现象特别显著,外界环境的干扰可能是导致物种成分替换的主要原因.图2表1参23     

Psychological stress and marginalization as indicators of human carrying capacity in deforesting areas

SUMMARY

A scheme in which psychological factors are considered in effective forest management planning is proposed. A central role is played by human carrying capacity, the resilience of people to deal with the consequences of environmental degradation. Stress and marginalization are taken as indicators of human carrying capacity. A study in Côte d'Ivoire is described in which psychological stress and marginalization were studied in individuals from environments which show different degrees of degradation. Three related hypotheses are proposed: first that individuals living in or near a degrading forest are more stressed and marginalized than individuals in a reference group living in Abidjan; second that people living near the forest with the most sustained and severe degradation would be more stressed and marginalized; finally, that members of autochthonous cultural groups show higher stress and marginalization levels than members of migrant groups. The results of our study showed that people living near the degraded forest were more stressed but not marginalized unless the degradation was severe and sustained. Females were more stressed than males and members of both sexes from autochthonous cultural groups were more prone to stress and marginalization than members of migrant groups.     

Shrinking Tropical Forests, Human Agents of Change, and Conservation Policy

Abstract:  Human agents of landscape transformation in the tropics affect forests differently as the forests decline in size. Five agents of change—road builders, corporate concession holders, community forest managers, park advocates, and urban consumers—have different effects on large forests in remote tropical regions than they do on remnant forests in settled agricultural regions. Because forests vary so much in size across tropical regions, these differences in the effects of agents on forests have important implications for regional conservation efforts. To make these implications explicit, I compared the effects of the five agents in regions with large forests with their effects in regions with small forests. The comparisons indicated that, as forests declined in size, new roads no longer destroyed forests, corporate loggers left the forests, community forest managers became more effective, parks became less feasible as a means of conservation, and urban consumers initiated tree planting. My results suggest that awareness about the changing effects of humans on landscapes with shrinking forests can serve as a useful tool in formulating regionally appropriate policies for conserving tropical forests.     

Aqua regia extractable trace elements in surface soils of venezuela

Surface soils (0–15 cm) were sampled at 10–20 km intervals along two transects in Venezuela. One (1162 km, 70 samples) ran west to east parallel with the Caribbean coastline, the other (920 km, 92 samples) ran south to north from the frontier with Brazil to the Caribbean shore. Sampling took place in both a wet and a dry season. Trace metals were extracted from dried, sieved (<2 mm) soil with boiling aqua regia followed by analysis by ICP or flame AAS. Metal values did not differ significantly between the two seasons and dates were averaged. Geometric mean values for the west–east transect were: Cr=41.5, Cu 17.9, Cs 3.6, Li=13.9, Mn=294, Ni=21.3, Pb=17.4, Sr=39.4, V=60.4 and Zn = 83.7g g^–1, respectively. Similarly, for the south–north transect Cr=21.3, Cu=4.3, Cs=1.1, Li=2.0, Mn=55.7, Ni=4.4, Pb=6.1, Sr=13.3, V=28.2 and Zn=16.7g g^–1, respectively. A classification of samples by lithology showed surface soil composition to be related to rock composition. Metal values were low in the soils in the south of the country, in the Guyana highlands (Gran Sabana). Low Zn contents were prevalent. Lead contents were affected by roadside fallout from vehicles using leaded petrol except that high Pb contents of soils in the Gran Sabana were of more complex origin.     

The distribution,metabolism and toxicity of 14c-DDT in model aquarium tanks with fish and sediment simulating a tropical marine environment

Studies conducted on the distribution, fate and metabolism of DDT in a model ecosystem simulating a tropical marine environment of fish, Gobious nudiceps, Lethrinus harak, Gobious keinesis, Gobious nebulosis and white shrimp (Panaeus setiferus), show that DDT concentration in the water decreases rapidly within the first 24?h. Rapid accumulation of the pesticide in the biota also reaches a maximum level in 24?h before gradually declining. The bioaccumulation factors calculated for the fish species (G. keinesis) and white shrimp (P. Setiferus) were 270 and 351, respectively, after 24?h. There was a steady build up of DDT residues in the sediment during the first 24?h which continued to a maximum concentration of 6.66?ng/g in the seawater/fish/sediment ecosystem after 3 weeks and 5.27?ng/g in the seawater/shrimps/sediment ecosystem after 2.7 days. The depuration of the accumulated pesticide was slow with only 54% lost in G. nudiceps within 3 days of exposure in fresh sea water. By contrast, depuration was fast in the white shrimp, which lost 97% of the accumulated pesticide under the same conditions. DDT was found to be toxic to two of the fish species (G. nebulosis and L. harak) and to white shrimp, and the degree of toxicity was dependent on the particular species. The 24?h LC₅₀ at room temperature for the fish species G. nebulosis and white shrimp was found to be 0.011 and 0.116?mg/kg, respectively. These levels are comparable to the ones recorded for the temperate organisms. Degradation of DDT to its primary metabolites, DDE and DDD, was found in all the compartments of the ecosystem with DDE being the major metabolite in the fish, shrimps and sediment, while in seawater, DDD dominated as the major metabolite.     

The environmental fate of thymol,a novel botanical pesticide,in tropical agricultural soil and water

In this study, the environmental fate of thymol, including hydrolysis, aqueous photolysis, soil sorption and soil degradation, was studied under conditions that simulated the tropical agricultural environment. This study was undertaken to supply basic information for evaluating the environmental risks of applying this new botanical pesticide to tropical crop production. The results showed that the hydrolysis of thymol was pH-dependent and accelerated by acidic conditions and high temperatures. However, the hydrolysis rate was far lower than the aqueous photolysis rate, indicating that direct photolysis is an important dissipation pathway for thymol in water. The sorption of thymol by three tropical soils was consistently well described by the Freundlich model, and the sorption coefficients increased in the order sandy soil < loamy soil < clay soil, a characterization that depended on the organic carbon contents of the soil. The soil degradation rate of thymol decreased in the order sandy soil > loamy soil > clay soil, which has a negative correlation with the sorption of thymol in soils. We concluded that the degradation rates of thymol in tropical soil and water are fast: thymol in water is photodegraded (50%) by sunlight within 28 h, and the thymol in soils is degraded (50%) within 8.4 d. Therefore, the environmental risk to the surrounding soils and water of thymol application for tropical crop production is low.     

Adsorption‐desorption hysteresis of α‐endosulfan in tropical soils using isotopic techniques

This study was designed to evaluate the adsorption‐desorption hysteresis of endosulfan (1,2,3,4, 7,7‐hexachlorobicyclo[2,2,1]‐2‐heptene‐5,6‐bisoxymethylene sulfite) in selected tropical soils. Two major tropical soils from Thailand were selected, Rangsit lowland soils (Rangsit series) and Phrabat upland soils (Pakchong series). The soil types were sub‐divided into plow soils, 0–20cm depth from the surface, and subsoils, 20–40cm depth. Adsorption was determined in 24h batch equilibrium, with five different concentrations of ¹⁴C endosulfan ranging from 1.04 to 16.64 ng/mg soils. Four successive desorption studies were performed continuously after three adsorption concentrations, 24h for each successive. Adsorption coefficient values (K _ads) as determined by Freundlich model ranged from 0.02 to 0.14 and found to be higher in Rangsit soils as expected when compared with Phrabat soils. Desorption was hysteresis in every desorption study. Desorption coefficient values (K _des) were higher than adsorption (K _des).     

热带人工林生物物理参数及生物量对RADARSAT SAR信号响应研究

合成孔径侧视雷达穿透冠层而获得树干信息的特点使得其具有在南方NDVI易饱和地区的生物量估测方面优于光学遥感。文章利用地面实测调查数据,首次系统地研究了热带人工林生物物理参数及生物量对RADARSAT-SAR信号响应。结果表明:RADARSAT-SAR后向散射系数与森林生物量、树高、胸径可以用对数模型模拟。对于本实验区人工速生林来说,在森林生物量小于40 t.hm-2时RADARSAT-SAR后向散射系数与森林生物量具有较强相关性。桉树树高与后向散射系数的相关系数大于桉树胸径与后向散射系数关系。松树胸径与后向散射系数相关系数高于树高与后向散射系数的相关系数。研究结果为SAR在热带森林研究中的应用提供了一定的理论基础。     

Comparative sensitivity of three life stages of the tropical mysid,Metamysidopsis insularis to six toxicants

Test protocols citing mysids as a standard test species often recommend juveniles (48 h) as the most appropriate life stage for testing. Acute toxicity tests were conducted with six standard toxicants, with three life stages of Metamysidopsis insularis; juveniles (48 h), late juveniles (7–12 days) and adults (>13 days), to determine whether there were significant differences in the sensitivity between life stages. Three of the compounds tested (sodium dodecyl sulphate, potassium dichromate, and potassium chloride) showed a significantly higher 96 h-LC₅₀ for the adults when compared to the juveniles and late juveniles. Four of the compounds tested showed significantly higher 24 h- and 48h-LC₅₀ for the adults when compared to both the late juveniles and juveniles. Twenty-four hour-LC₅₀ values for juveniles were also significantly higher than the 48 and 96 h values. However, for the late juveniles and adults this was only true of a few compounds. Further, the 48 and 96 h values were statistically similar. Therefore, for M. insularis it may be appropriate to conduct acute toxicity test with juvenile for a 48 h period.     

热带林业实验中心森林病虫害防治对策

林病虫害已成为林业发展的一大难题,对中国林科院热带林业实验中心森林病虫害类型、危害特点等进行分析,并提出了具体有效防治措施与方法.参6.     

Frog, Bat, and Dung Beetle Diversity in the Cloud Forest and Coffee Agroecosystems of Veracruz, Mexico

Abstract:  We compared the species diversity of copronecrophagous beetles (Scarabaeinae) , bats, and frogs in tropical montane cloud forest (original vegetation) and shaded coffee plantations (an agroecosystem common to the region) for a landscape in central Veracruz, Mexico. We sampled in three tropical montane cloud forest fragments and in three coffee plantations with traditional polyculture shade between 1998 and 2001. The three indicator groups responded differently to the transformation of tropical montane cloud forest into shaded coffee plantations. The species richness of frogs was one-fifth less in coffee plantations than in forest fragments, and only one-third of the frog species occurred in both forest fragments and coffee plantations. The number of beetle species and their abundance was significantly greater in coffee plantations than in the forest fragments, whereas species richness and species composition of bats were virtually the same in both habitats. The majority of the abundant species remained as such in both communities, but species that were less abundant were not scarce in both habitats. We attributed differences in the species assemblages to the differing degrees of penetrability of the borders of the two habitat types (especially for the coffee plantations) and to the differences in life-history traits among species. Shaded coffee plantations form a matrix that envelops the remaining fragments of cloud forest. Together they connect the forest fragments with the other habitats of the landscape and represent a highly functional resource for the preservation of biodiversity that serves as a complement to but not a substitute for cloud forest in this notably modified landscape.