Effects of Selection Logging on Birds in Northern Belize1

We compared bird diversity and frequency in selection logged and unlogged forest to determine the effects of recent selection logging on avian biodiversity in a subtropical, moist evergreen forest. We used a combination of mist netting and fixed-radius point counts to assess bird communities in February and March 1993 in northwestern Belize. Vegetation structure and composition was similar in logged and unlogged forest. The 66 most common species occurred with statistically similar frequency in logged and unlogged forest although 13 species were two times more frequent in intact forest. Numbers of total bird species were similar between logging gaps and the logged forest matrix, and between the logged forest matrix and unlogged forests. A comparison of numbers of species in 26 guilds based on migration strategy, diet, foraging substrate, and height strata also showed them to be similar regardless of logging history. Our results differed from previous studies that reported lower bird species richness and abundance of individual species in logged tropical forests than in unlogged forest. The differences might be explained by the lower logging intensity and/or greater levels of natural disturbance in our study area compared to previous studies.     

The implications of improved communications for participatory forest management in Tanzania

Following the 1998 National Forest Policy and Forest Act of 2002, participatory forest management (PFM) is being introduced in Tanzania. PFM has two key objectives: to reduce forest degradation thereby increasing ecosystem services, and to improve the livelihoods of local villagers. A unique data set collected in 2006 suggests that significant challenges remain with respect to communicating the new forest policies if the objectives of PFM are to be achieved. First, villagers as a group are much less well informed than other stakeholders, and their knowledge is often inaccurate. Second, women are less likely than men to have heard of the changes. Third, how PFM will contribute to poverty reduction (a key objective of PFM) is not always clear. Fourth, environmental degradation may not be reduced as much as anticipated – without alternatives sources, villagers often continue to cut trees for charcoal and firewood in the protected forests. Finally, several mismatches in perceptions are identified that could lead to difficulties in implementing PFM.     

Traditional management of forests: plant and bird community responses to alternative restoration of oak–hazel woodland in Sweden

Species richness of vascular plants and birds were examined in relation to five types of management (including abandonment) of oak-hazel woodland in south-central Sweden. The biodiversity of this type of woodland is affected by lengthy management in contrast to present emphasis on the fragmentation of more or less pristine forests. The woodlands derive from old deciduous forests but were a source of agricultural commodities from medieval time to end of the 19th century. Vascular plants and birds were censused during spring–summer for four years. Total number of plant species, species of field layer forbs, breeding birds and migrant birds were more numerous at simulated original management with mowing of small interior grasslands than at mechanical clearing or abandonment. Summer grazing led to intermediate numbers. Exotic plants were more common at long-time abandonment. Species richness of trees and shrubs, graminoids, all spring birds, resident birds and non-passerine birds did not exhibit any difference between treatments. Inter-site variation in species richness was usually smaller at abandonment than at true management. Species richness of plants and birds showed positive correlation in the particularly large sites examined. The general findings were in accordance with the intermediate disturbance hypothesis. Original management would secure most potential plant and bird species but extensive cattle grazing would also retain many species.     

The peninsula effect on bird species in native eucalypt forests in a wood production landscape in Australia

The peninsula effect – a decrease in species richness from the base to the tip of a peninsula – has been tested for a diverse range of taxa at continental and regional scales. We investigated the peninsula effect at a local scale by examining bird species occurrence in riparian strips (peninsulas) of native eucalypt forest within a radiata pine plantation in the Tumut region, south-eastern Australia. Peninsulas were elongated but 'blind' extensions of a core area of native eucalypt forest. Birds were surveyed by the area search method, within 1.0-ha quadrats established along peninsulas ( n =14), in October and November 2002. Data were analysed using generalized linear mixed models. A significant decrease in bird species richness from the base towards the tip of the peninsulas was observed. The proportion of large bird species recorded per quadrat showed a significant decrease from the base towards the tip of the peninsulas. This pattern was not observed for small birds. Several species were more abundant at the base of the peninsulas than away from the core area of eucalypt forest. The peninsula effect can occur locally in landscape mosaics. Factors leading to the observed patterns of species occurrence may be distinct from those proposed in investigations of the peninsula effect with a biogeographical (macroscale) context. In our microscale study, foraging incursions of individual birds from the core area of native forest through peninsulas were a major factor giving rise to higher bird species richness in the more basal portions of peninsulas.     

Have we been successful? Monitoring horizontal forest complexity for forest restoration projects

Forest management today often seeks to restore ecological integrity and enhance human well‐being by increasing forest complexity, resilience, and functionality. However, effective and financially expedient monitoring of forest complexity is challenging. In this study, we developed a practical and inexpensive technique to measure horizontal forest complexity. This monitoring method uses intuitively understandable data (imagery) and facilitates stakeholder participation in the adaptive management process within collaborative projects. We used this technique to determine if current restoration projects are successfully achieving their spatial restoration goals. We focused on the Colorado Front Range Landscape Restoration Initiative (CFRLRI) as a representative of the typical collaborative restoration projects underway in formerly fire‐dependent dry conifer forests. The developed monitoring method is practical and cost‐effective by using free aerial imagery to map, quantify, and analyze the distribution of canopy cover pre‐ and post‐treatment. We found the CFRLRI has successfully reduced canopy cover (from 44 to 26% on average) and increased some aspects of horizontal forest complexity. The application of these monitoring techniques has allowed the CFRLRI collaborative group to objectively quantify changes to horizontal forest complexity, and has facilitated stakeholder communication about forest spatial patterns. These methods could be adapted for use by other similar forest restoration projects around the world by utilizing increasingly available satellite or aerial imagery.     

森林木质藤本数量过度增长的机制与生态效应

木质藤本是维持森林物种多样性的组成部分。近年来,热带、亚热带森林尤其是次生林内的木质藤本数量的过度增长给森林的恢复和健康发展造成了威胁。至今,国内尚少有研究对森林木质藤本过多的现象、增长机制与生态效应进行综合认识。该文梳理国内外相关文献,从木质藤本数量增长的机制与生态效应进行分析和总结,综合相关研究认为：(1)木质藤本数量的增长与干旱化加剧、大气CO₂浓度上升、自然干扰和森林破碎化有关,在环境变化的情况下,木质藤本在形态、行为、生理等方面比树木更具优势,表现为更快的生长速率、更强的繁殖力和可塑性以及资源利用效率。(2)木质藤本主要通过遮荫胁迫、资源竞争和机械压力与损伤等方式对树木造成影响。(3)木质藤本过度增长在个体水平上会阻碍树木生长、生殖并引起树木死亡,在群落水平上会改变物种组成、降低多样性,在生态系统水平上会降低森林碳储量,改变碳、矿质养分和水分循环过程等。因此,建议结合野外长期监测与控制实验开展木质藤本数量动态与环境变化关系、森林干扰对木质藤本生长的影响、木质藤本对环境变化的响应及适应机理、木质藤本数量过度增长的生态效应评价研究。同时,应积极探索合理的森林...     

Habitat relationships of forest birds on Tutuila Island, American Samoa

Aim Our knowledge of landbirds on tropical Pacific islands is often comprised of brief, one-time surveys. We know little of species’ habitat preferences, and this information is critical for understanding the resource requirements or population status of native species and the impacts of human activity on island birds. Location Tutuila Island, American Samoa. Methods The spatial patterns in forest birds were investigated. This island harbours large tracts of native forest, a variety of disturbed and non-native forests, and some relatively healthy bird populations. The distribution of birds was correlated with forest types using habitat data collected at fifty-seven sites and avian census data collected monthly for 1–4 years at these sites. Results Differences in location and in vegetation structure and composition between native and non-native habitats are important influences on the distribution of birds on Tutuila. Among native species, for example, the purple-capped fruit-dove (Ptilinopus porphyraceus Temminck) is dependent upon native habitat, the Samoan starling (Aplonis atrifusca Peale) occurs in all habitats, and the cardinal honeyeater (Myzomela cardinalis Gmelin) is more abundant in low elevation, non-native habitat. Conclusions This research reinforces the importance of quantitative assessment of habitat relationships in the study and conservation of Pacific birds.     

次生林概念与生态干扰度

近一个世纪强烈的人为干扰使世界范围内的原始林面积锐减,次生林已成为中国乃至世界森林资源的主体.虽然在文献与现实中\"次生林（Secondary forest）\"被广泛使用,但次生林的概念在各个国家,甚至同一国家或地区以及各种不同文献中存在相互矛盾的情况,这给次生林研究与经营实践带来诸多不便;而不准确的次生林定义也为与各个层次的决策制定者及公众之间的交流带来了障碍.本文在查阅大量国内外关于次生林概念文献的基础上,结合近年来关于次生林生态与经营研究实践,综合分析了次生林概念的不确定性,同意以往次生林定义中的基本内涵,并认为：次生林是由于人为破坏性干扰或异常自然干扰使原始林固有的林分结构、物种组成或基本功能发生了显著变化,经过天然更新或人工诱导天然更新恢复形成的林分.但该定义中仍存在着很多不确定性, 如:怎样的干扰为\"人为破坏性干扰\"和\"异常自然干扰\";\"林分结构、物种组成或基本功能\"发生了怎样的变化为\"显著变化\";\"人工诱导天然更新\"中\"人工\"参与的成分比例如何等.次生林概念是在20世纪初由植物演替学家提出,当时未考虑干扰的持续性;而实际上,无论是次生林还是原始林,均是森林生态系统演替过程中的某一状态,在现代森林生态系统研究中,应重新规范\"次生林\"的概念.考虑到\"次生林\"定义的不确定性或困难性,建议使用\"森林自然度\"或\"森林生态系统成熟度\"或\"森林干扰度\"来表达现实森林所处的状态,但该方面的研究与实践尚需加强.     

Ecological study of pseudoscorpion fauna in the soil organic layer in managed and abandoned secondary forests

We surveyed pseudoscorpion fauna in the soil organic layer in managed and abandoned secondary forests in Hiroshima Prefecture, Japan, and studied the effects of forest management on the pseudoscorpions. The vegetation structure was generally more developed in abandoned stands than in managed stands. The depth of the soil organic layer was not significantly different between the two stand types. We observed a total of seven pseudoscorpion species belonging to five genera. Pseudoscorpion species richness and densities were higher in abandoned stands than in managed stands. We did not find any pseudoscorpions in stands where the summed vegetation cover was less than 150%.An erratum to this article can be found at