马达加斯加森林开发

砍伐森林不是一种新现象．在这项研究中，一些数据用来表示马达加斯加在不同方面对森林开发和利用．基于本文研究的目的，我们定义了主要开发用法，譬如非法木材业，灌木火，耕种和燃料采伐．结果表明，那些测量的数据非常重要以致于引起我们足够的重视，而且数据表明在今后几年中森林砍伐量将达到最大值．     

南京市典型森林群落枯枝落叶层的生态功能研究

对南京市5种典型森林群落枯枝落叶层现存量、营养元素氮磷贮存量、持水量以及吸纳重金属等生态功能的研究结果表明,5种典型森林群落枯枝落叶层现存量、对氮的贮存能力以及最大拦蓄量均以麻栎-栓皮栎群落最大;对磷和5种重金属的贮存量以银杏群落最大,麻栎-栓皮栎群落次之;枫香-桂花和三角枫群落的各项生态功能相对较弱。建议在南京市的城市森林规划和建设中,应保护好现存的地带性植物群落———以麻栎-栓皮栎为优势种的落叶阔叶林群落或营建类地带性植物群落,维护林地枯枝落叶层的完整性,将有助于改善城市生态环境。     

Linear Strips of Rain Forest Vegetation as Potential Dispersal Corridors for Rain Forest Insects

The potential of linear strips of vegetation to act as corridors to facilitate dispersal is examined for three taxa of insects in lowland rain forest in northeastern Australia. The taxa selected were ants, butterflies, and dung beetles, all of which are taxonomically well known and could be considered bioindicator groups. The sampling design encompassed four habitats, namely rain-forest interior, rain-forest edge, rain-forest linear strip (corridor), and arable land. Ants and dung beetles were sampled using baited pitfall traps, and visual surveys were used to census butterflies. Potential increase in dispersal was examined by first identifying those species that specialized on the rain-forest interior habitat and then determining whether these species were present in the linear strips as opposed to the surrounding arable land. Two species of butterfly and two species of dung beetle were identified as rain-forest interior specialists, and two of these species were found in the linear strips but not in the arable habitat. This result supports the concept that the presence of corridors can increase the potential for dispersal of these species. But the remaining rain-forest interior species did not occur in the linear strips, which suggests that corridors will not increase dispersal for these species.     

沙质海岸带木麻黄林与天然林主要种群的生态位特征比较

通过样地调查比较分析了沙质海岸带木麻黄(Casuarina equisetifolia)林与天然林主要种群的生态位宽度和生态位重叠这2种重要的生态位特征。结果表明,依照各种群在2种林分中生态位宽度的变化,可将其划分为生态位扩展型、衰退型、敏感型和稳定型4个种群类型;天然林中的演替优势种在木麻黄林的灌木种群中已有较大数量的分布,且具有较大的生态位宽度值,但由于人工林生态位分化不良,种间竞争相对激烈,群落组成不稳定;天然林中大部分乡土树种生态位宽度较之在木麻黄林中大为增加,但除敏感型种群和潺槁木姜子(Litsea glutinosa)、雀梅藤(Sageretia thea)以外,天然林中其他种群的生态位重叠值较之在木麻黄林中有所降低,说明经过长期的协同进化,天然林种间生态位分化程度高,竞争相对缓和。总体来看,以乡土树种为优势种的天然林生态位配置比人工林更优化,对维持群落的稳定更有意义,因此实现乡土树种与木麻黄的合理配置对建设稳定型沿海防护林体系具有重要的参考价值。     

Invertebrates and Boreal Forest Management

Logging has ecological effects on invertebrates in Fennoscandian boreal forest. Especially affected are species associated with micro-habitats of natural old-growth forest, such as coarse woody debris, large deciduous trees, and patches of wet swamp-forest. Furthermore, the effective control of forest fires has adversely affected many species that require burned substrates. Although old-growth specialists tend to disappear from clear-cuts, local invertebrate species richness (α-diversity) may increase as forest generalists persist and numerous open-habitat species appear. This seems true at least for taxa (e.g., ground-beetles and spiders) that are not directly associated with the characteristic micro-habitats of old growth mentioned above. However, at the landscape or biogeographical scale intensive logging tends to homogenize forest habitats and lead to declines of sensitive species. Based on these findings three complementary approaches appear useful for the maintenance of boreal biodiversity while harvesting timber. (1) Undisturbed old-growth forests must be set aside to sustain specialist species and to serve as sources for recolonization. (2) Because these reserves are not, and will probably not be, large and regionally representative enough, ecologically sound silvicultural practices must be developed using natural disturbance regimes as guidelines. (3) Restoration of habitats and the process of natural regeneration through fire is imperative for the recovery of associated species assemblages. However, the process of recovery presupposes that colonists are available, which may not always be the case.     

Remote Forest Refugia for Fijian Wildlife

Abstract:  On Pacific islands non-native rats and mongooses threaten many native species. In Fiji we compared visitation rates of rats and mongooses at bait stations and measured biomass of leaf-litter invertebrates to assess the relative predation pressure from these species in forest areas at different distances from the forest edge. Forest areas over 5 km from the forest edge had significantly fewer baits encountered by rats or mongooses than did natural forest areas nearer agricultural and urban habitats. Remote forest areas may function as a last refuge for island species threatened by predation from non-native rats and mongooses. The biomass of leaf-litter invertebrates in remote forest areas was higher, indicating a refuge effect for some taxa targeted by rats and mongooses. Protection of the few remaining large blocks of natural forests on Pacific islands may be the most cost-effective approach for conserving many island endemics threatened by rats and mongooses. Logging roads can compromise this refuge effect by acting as dispersal routes for rats into natural forests.     

Transvalued Species in an African Forest

Abstract: We combined ethnographic investigations with repeated ecological transect surveys in the Dzanga‐Sangha Dense Forest Reserve (RDS), Central African Republic, to elucidate consequences of intensifying mixed use of forests. We devised a framework for transvaluation of wildlife species, which means the valuing of species on the basis of their ecological, economic, and symbolic roles in human lives. We measured responses to hunting, tourism, and conservation of two transvalued species in RDS: elephants (Loxodonta cyclotis) and gorillas (Gorilla gorilla). Our methods included collecting data on encounter rates and habitat use on line transects. We recorded cross‐cultural variation in ideas about and interactions with these species during participant observation of hunting and tourism encounters and ethnographic interviews with hunters, conservation staff, researchers, and tourists. Ecologically, gorillas used human‐modified landscapes successfully, and elephants were more vulnerable than gorillas to hunting. Economically, tourism and encounters with elephants and gorillas generated revenues and other benefits for local participants. Symbolically, transvaluation of species seemed to undergird competing institutions of forest management that could prove unsustainable. Nevertheless, transvaluation may also offer alternatives to existing social hierarchies, thereby integrating local and transnational support for conservation measures. The study of transvaluation requires attention to transnational flows of ideas and resources because they influence transspecies interactions. Cross‐disciplinary in nature, transvalution of species addresses the political and economic challenges to conservation because it recognizes the varied human communities that shape the survival of wildlife in a given site. Transvaluation of species could foster more socially inclusive management and monitoring approaches attuned to competing economic demands, specific species behaviors, and human practices at local scales.     

Rarity in Neotropical Forest Mammals Revisited

The identification of rare species is an important goal in conservation biology. Recent attempts to classify rare species have emphasized dichotomies in such characteristics as local population density, area of distribution, and degree of ecological specialization. In particular, Arita et al. (1990) dichotomized 100 Neotropical forest mammals according to local population density and area of distribution. Among these species of mammals, mean body mass was significantly associated with local population density and area of distribution. We argue that the effects of body mass should be removed before species are classified with respect to rarity. We re-evaluated the data on Neotropical mammal species, using regression analyses to remove the effects of body mass on population density and area of distribution, followed by analysis of residuals. This new method resulted in substantial changes in the dichotomous classification of rare species. We combined the analysis of regression residuals with a ranking procedure that assumed that local population density and area of distribution were equally important in their effects on rarity. The new ranking technique produced another different classification of the rarity of the Neotropical forest mammal species. A graphical analysis showed that ranked species differed substantially in their degree of rarity, and in the importance of local population density, area of distribution, or both, to their degree of rarity. The ranking method allows the species of greatest concern to be singled out, it can be modified to include additional variables such as niche breadth, and it should be helpful for making conservation decisions.