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1.
As large nature reserves occupy only a fraction of the earth’s land surface, conservation biologists are critically examining the role of private lands, habitat fragments, and plantations for conservation. This study in a biodiversity hotspot and endemic bird area, the Western Ghats mountains of India, examined the effects of habitat structure, floristics, and adjacent habitats on bird communities in shade-coffee and cardamom plantations and tropical rainforest fragments. Habitat and birds were sampled in 13 sites: six fragments (three relatively isolated and three with canopy connectivity with adjoining shade-coffee plantations and forests), six plantations differing in canopy tree species composition (five coffee and one cardamom), and one undisturbed primary rainforest control site in the Anamalai hills. Around 3300 detections of 6000 individual birds belonging to 106 species were obtained. The coffee plantations were poorer than rainforest in rainforest bird species, particularly endemic species, but the rustic cardamom plantation with diverse, native rainforest shade trees, had bird species richness and abundance comparable to primary rainforest. Plantations and fragments that adjoined habitats providing greater tree canopy connectivity supported more rainforest and fewer open-forest bird species and individuals than sites that lacked such connectivity. These effects were mediated by strong positive effects of vegetation structure, particularly woody plant variables, cane, and bamboo, on bird community structure. Bird community composition was however positively correlated only to floristic (tree species) composition of sites. The maintenance or restoration of habitat structure and (shade) tree species composition in shade-coffee and cardamom plantations and rainforest fragments can aid in rainforest bird conservation in the regional landscape.  相似文献   

2.
三江平原湿地鸟类丰富度的空间格局及热点地区保护   总被引:1,自引:0,他引:1  
刘吉平  吕宪国 《生态学报》2011,31(20):5894-5902
全球气候变化和人类的开垦开发活动使湿地生物多样性遭到严重的干扰和破坏,导致生物多样性空间分布格局及热点地区的保护成为研究的热点。在对三江平原湿地鸟类预测的基础上,利用空间自相关方法分析三江平原湿地鸟类丰富度的空间分布格局,并找出湿地鸟类多样性的热点地区及优先保护顺序。研究结果表明,三江平原湿地鸟类丰富度高高集聚区主要分布在保护区及周边地区、河流和湖泊沿岸,是新建和扩建自然保护区的最佳区域。湿地鸟类丰富度高低集聚区主要分布在农田景观中,将它们设立成微型保护地块对于区域景观生态安全具有重要意义;利用湿地鸟类物种丰富度、国家级保护湿地鸟类、生境类型和结构、距最近保护区距离、破碎度、干扰度等指标,在研究区内共找到13个热点地区,总面积为1018.7km2,占研究区总面积的8%;利用系统聚类分析,将13个热点地区划分成3种优先保护顺序。构建的小区域范围内寻找生物多样性热点地区的方法,为相关政府部门更有效地进行湿地生物多样性的保护和管理提供科学依据。  相似文献   

3.
Evaluating the effectiveness of protected areas for sustaining biodiversity is crucial to achieving conservation outcomes. While studies of effectiveness have improved our understanding of protected‐area design and management, few investigations (< 5%) have quantified the ecological performance of reserves for conserving species. Here, we present an empirical evaluation of protected‐area effectiveness using long‐term measures of a vulnerable assemblage of species. We compare forest and woodland bird diversity in the Australian Capital Territory over 11 yr on protected and unprotected areas located in temperate eucalypt woodland and matched by key habitat attributes. We examine separately the response of birds to protected areas established prior to 1995 and after 1995 when fundamental changes were made to regional conservation policy. Bird diversity was measured in richness, occurrence of vulnerable species, individual species trajectories and functional trait groups. We found that protected areas were effective in maintaining woody vegetation cover in the study region, but were less effective in the protection of the target bird species assemblage. Protected areas were less species rich than unprotected areas, with significant declines in richness across sites protected prior to 1995. Small, specialised and vulnerable species showed stronger associations with unprotected areas than protected areas. Our findings indicate that recently established reserves (post‐1995) are performing similarly to unprotected woodland areas in terms of maintaining woodland bird diversity, and that both of these areas are more effective in the conservation of woodland bird populations than reserves established prior to 1995. We demonstrate that the conservation value of protected areas is strongly influenced by the physical characteristics, as well as the landscape context, of a given reserve and can diminish with changes in surrounding land use over time. Both protected areas and off‐reserve conservation schemes have important roles to play in securing species populations.  相似文献   

4.
Areas allocated for industrial logging and community‐owned forests account for over 50% of all remaining tropical forests. Landscape‐scale conservation strategies that include these forests are expected to have substantial benefits for biodiversity, especially for large mammals and birds that require extensive habitat but that are susceptible to extirpation due to synergies between logging and hunting. In addition, their responses to logging alone are poorly understood due to their cryptic behavior and low densities. In this study, we assessed the effects of logging and hunting on detection and occupancy rates of large vertebrates in a multiple‐use forest on the Guiana Shield. Our study site was certified as being responsibly managed for timber production and indigenous communities are legally guaranteed use‐rights to the forest. We coupled camera‐trap data for wildlife detection with a spatially explicit dataset on indigenous hunting. A multi‐species occupancy model found a weak positive effect of logging on occupancy and detection rates, while hunting had a weak negative effect. Model predictions of species richness were also higher in logged forest sites compared to unlogged forest sites. Density estimates for jaguars and ocelots in our multiple‐use area were similar to estimates reported for fully protected areas. Involvement of local communities in forest management, control of forest access, and nesting production forests in a landscape that includes protected areas seemed important for these positive biodiversity outcomes. The maintenance of vertebrate species bodes well for both biodiversity and the humans that depend on multiple‐use forests.  相似文献   

5.
The impacts of human pressure, habitat changes, and efficiency of conservation measures on the non-passerine bird community were assessed in the Sudanian belt of Burkina Faso. Three regions with increasingly large protected areas and higher conservation status were compared. In each region, natural savanna woodlands were also compared to traditionally cultivated areas. Six groups of diurnal raptors and six groups of other large bird species were counted along 167 5-km transect counts during the dry season. Within savanna woodlands, the only significant and consistent declines from the little disturbed Eastern National Parks to the more populated and exploited Western forest reserves were those of the largest terrestrial game birds (Guinea fowl, Bustard, Ground Hornbill), eagles and vultures, which became virtually extinct in the least protected areas. Although some species groups maintained substantial, if not higher populations in cultivated areas (rollers, non-game terrestrial birds, several raptors), the overall abundance of both raptor and non-raptor species declined markedly (50–65%) from natural savanna woodlands to tree-dotted cultivated and fallow fields. Again large game birds, eagles and vultures were absent from every agricultural areas censused. Yet, all of them were still commonly recorded in the same natural and cultivated areas during surveys I conducted in the same regions from 1968 to 1973. The main factors correlated with large bird extinctions or declines from national parks to mere forest reserves and from natural woodlands to fields were first related to hunting, then to habitat degradation and fragmentation through intensive cattle grazing and wood cutting and extension of cultivated areas.  相似文献   

6.
Although an increasing number of studies have shown that diverse, multi-strata agroforestry systems can contribute to the conservation of tropical biodiversity, there is still debate about how the biodiversity within agroforestry systems compares to that of intact forest and alternative land uses. In order to assess the relative importance of agroforestry systems for biodiversity conservation, we characterized bat and bird assemblages occurring in forests, two types of agroforestry systems (cacao and banana) and plantain monocultures in the indigenous reserves of Talamanca, Costa Rica. A total of 2,678 bats of 45 species were captured, and 3,056 birds of 224 species were observed. Agroforestry systems maintained bat assemblages that were as (or more) species-rich, abundant and diverse as forests, had the same basic suite of dominant species, but contained more nectarivorous bats than forests. Agroforestry systems also contained bird assemblages that were as abundant, species-rich and diverse as forests; however the species composition of these assemblages was highly modified, with fewer forest dependent species, more open area species and different dominant species. The plantain monocultures had highly modified and depauperate assemblages of both birds and bats. Across land uses, bird diversity and species richness were more closely correlated with the structural and floristic characteristics than were bats, suggesting potential taxon-specific responses to different land uses. Our results indicate that diverse cacao and banana agroforestry systems contribute to conservation efforts by serving as habitats to high numbers of bird and bat species, including some, but not all, forest-dependent species and species of known conservation concern. However, because the animal assemblages in agroforestry systems differ from those in forests, the maintenance of forests within the agricultural landscape is critical for conserving intact assemblages at the landscape level.  相似文献   

7.
Bird habitat conservation may require different management strategies for different seasonal bird assemblages. We studied habitat use by winter birds in forest and scrubland habitat patches in the northern Negev, Israel. Our goal was to assess whether differences in responses to landscape and habitat structure between breeding and non-breeding seasons require changes in future conservation plans that have been suggested for the Negev breeding bird community. We evaluated habitat and area effects on bird abundance and distribution and tested whether species habitat use during winter involves niche shifts. Compared with breeding birds, a larger proportion of winter bird species occupied both scrubland and forest. As in summer, forest bird species responded to habitat structure, whereas scrubland species were associated with both habitat structure and area. Resident birds disperse into habitats in which they were not present during summer. Consequently, for several species, the correlation between bird densities and environmental factors showed a better fit at the landscape rather than at the habitat scale. In addition, rather than niche shift, birds actually extended their niche breadth. Nest site selection may constrain bird distribution into a realized niche, smaller than their fundamental niche. Despite the scale differences in habitat use, the similar species diversity patterns between seasons suggest that both winter and summer birds would benefit from conservation of scrub patches larger than 50 ha, and enrichment of foliage layers within the planted forests.  相似文献   

8.
实现有效生物多样性保护的关键在于提升生物多样性丰富的人口密集区的保护效率。北京人口密集且生物多样性丰富, 存在3类具有生态保护功能的区划——自然保护区、生态保护红线和限制建设线。上述区域可视为生态保护潜力区。本文以在北京有分布的30种受胁鸟类为主要对象, 探讨现有生态保护潜力区对这些物种栖息地的覆盖程度, 并对如何改善上述受胁鸟类栖息地的保护状况进行了建议。根据物种对栖息地的选择, 基于高分辨率卫星解译的土地利用类型图, 利用最大熵模型(MaxEnt)掩膜栖息地分布图, 得到各受胁鸟类的预测空间分布。叠加这些分布获得北京受胁鸟类丰富度分布格局并进行验证。依据物种丰富度高低, 将受胁鸟类栖息地划分为一至四级(最重要的栖息地是一级栖息地, 以此类推)。同时, 依据地表覆盖类型和人类活动强度高低将北京市域划分为城市建成区、乡村生境区和自然生境区。分别计算3类保护潜力区对上述3类区域以及四级栖息地的覆盖面积比例。结果表明: (1) 95.64%的一级关键栖息地和86.32%的二级关键栖息地分布在乡村生境区, 但仅有0.69%和15.15%的乡村生境区分别被自然保护区和生态保护红线覆盖; (2)未受到自然保护区和生态保护红线覆盖的一、二级关键栖息地主要为水域和沼泽地等湿地、高覆盖度草地和部分耕地, 以及含有较高比例水体的大型城市绿地。基于以上结果, 我们建议至少在一定区域内试行如下保护措施: (1)严格保护湿地及其周边的高覆盖度草地, 确保面积不减少; (2)维持基本农田规模和粮食种植模式; (3)将乡村生境区位于河道附近的水域、沼泽地、高覆盖草地和灌木林纳入生态保护红线范围; (4)在公园绿地中划定生物多样性保护区; (5)优化平原地区林地结构。以上措施将使北京的受胁鸟类栖息地得到更好保护, 为中国东部人口密集区生物多样性保护提供示范。  相似文献   

9.
Hunting is one of the human activities that directly affect wildlife and has received increasing attention given its socioeconomic dimensions. Most studies have been conducted on coastal and wetland areas and showed that hunting activity can greatly affect bird behaviour and distribution. Hunting-free reserves for game species are zones where birds find an area of reduced disturbance. We evaluated the effect of hunting activities on the behaviour and use of hunting-free areas of lapwings Vanellus vanellus , golden plovers Pluvialis apricaria and little bustards Tetrax tetrax in agricultural areas. We compared the habitat use and behaviour of birds on days before, during and after hunting took place. All three studied species showed strong behavioural responses to hunting activities. Hunting activity increased flight probability and time spent vigilant (higher on hunting days than just before and after a hunting day), to the detriment of resting. We also found distributional (use of hunting-free reserve) responses to hunting activities, with hunting-free reserves being used more frequently during hunting days. Thus, reserves can mitigate the disturbance caused by hunting activities, benefiting threatened species in agricultural areas. Increasing the size or number of hunting-free areas might be an important management and conservation tool to reduce the impacts of hunting activities.  相似文献   

10.
基于ZONATION的岷山山系多物种保护规划   总被引:1,自引:0,他引:1  
肖静  崔莉  李俊清 《生态学报》2016,36(2):420-429
空间布局不尽合理是我国的自然保护区发展面临的问题之一,优化现有的自然保护区体系是在资源有限的情况下实现自然保护区的保护效益最大化的最佳途径。以岷山地区为主要研究区域,以25种珍稀濒危物种为主要研究对象,通过MAXENT与ZONATION模型模拟,鉴别出岷山地区珍稀濒危物种保护优先区,并提出了自然保护区空间选址的优化方案。研究结果表明,(1)在物种出现点记录较少的情况下,MAXENT模型依然能够比较准确地预测出物种的分布状况;(2)目前建立的保护区对25个物种的平均保护比例为51.8%;(3)通过ZONATION鉴定的优先区总面积为19958.7 km~2,岷山地区现有的29个自然保护区只保护了目标优先区的47.1%,九寨沟中部与南部,平武北部,平武与北川的交界处,北川西北部等地都存在保护空缺。建议在保护空缺的6个地方新建或扩建自然保护区,并在规划时考虑这些区域内部的优先次序。新提出的保护体系能将物种栖息地的保护比例提高至77.9%。研究结果对于岷山及全国其他生物多样性保护关键地区保护体系的规划都具有重要的借鉴意义。  相似文献   

11.
Protected areas are meant to preserve native local communities within their boundaries, but they are not independent from their surroundings. Impoverished habitat quality in the matrix might influence the species composition within the protected areas through biotic homogenization. The aim of this study was to determine the impacts of matrix quality on species richness and trait composition of bird communities from the Finnish reserve area network and whether the communities are being subject of biotic homogenization due to the lowered quality of the landscape matrix. We used joint species distribution modeling to study how characteristics of the Finnish forest reserves and the quality of their surrounding matrix alter species and trait compositions of forest birds. The proportion of old forest within the reserves was the main factor in explaining the bird community composition, and the bird communities within the reserves did not strongly depend on the quality of the matrix. Yet, in line with the homogenization theory, the beta‐diversity within reserves embedded in low‐quality matrix was lower than that in high‐quality matrix, and the average abundance of regionally abundant species was higher. Influence of habitat quality on bird community composition was largely explained by the species' functional traits. Most importantly, the community specialization index was low, and average body size was high in areas with low proportion of old forest. We conclude that for conserving local bird communities in northern Finnish protected forests, it is currently more important to improve or maintain habitat quality within the reserves than in the surrounding matrix. Nevertheless, we found signals of bird community homogenization, and thus, activities that decrease the quality of the matrix are a threat for bird communities.  相似文献   

12.
The lowland areas of the Himalayan region are subjected to immense anthropogenic pressure because of least representation in the protected area network. Kitam Bird Sanctuary is the only representative protected area that occurs below 1000 m in Sikkim state of India (a part of globally significant biodiversity hotspot of Himalayas) and serves as the refuge for various species of flora and fauna. Here we studied butterfly diversity and community composition in Kitam Bird Sanctuary (a small protected area of 6 km2 geographical area) following point count method spread across predetermined transects. Altogether 1674 butterflies belonging to 111 species and six families were recorded after completion of 240 point counts. Among these, 18 species are federally protected under the Wildlife (Protection) Act (1972) of India. Most of the butterflies were forest specialist in terms of habitat preference, whereas based on host plant specificity, the butterfly community was mostly dominated by generalist feeder (Oligophagous II and Polyphagous). Butterfly community parameters showed a strong correlation with habitat variables. While Kitam Bird Sanctuary is primarily designated for conservation of lowland birds, the high diversity of butterflies both in terms of taxonomic richness and trait composition suggests that the sanctuary harbors an ideal habitat for butterflies of the tropical region and invites conservation attention.  相似文献   

13.
掌握野生动植物本底资源是各级自然保护区生物多样性监测研究和保护管理的重要环节。为了建立龙溪-虹口国家级自然保护区内兽类和鸟类多样性资源的长期监测机制,于2013年9月至2014年11月,我们采用红外相机技术在龙溪沟和虹口峡谷等区域按公里网格布设了57个监测点,调查地面活动的兽类和鸟类。红外相机累计工作达11,847个工作日,共记录到兽类和鸟类物种61种,其中兽类5目12科21种,鸟类3目10科40种,包括猎隼(Falco cherrug)、光背地鸫(Zoothera mollissima)、长尾地鸫(Zoothera dixoni)、灰翅鸫(Turdus boulboul)、锈脸钩嘴鹛(Pomatorhinus erythrogenys)、红嘴鸦雀(Conostoma aemodium)和褐鸦雀(Paradoxornis unicolor)7种鸟类为保护区新记录种。调查到的兽类被列为国家I级和II级重点保护野生动物的分别为4种和5种,被IUCN红色名录评估为“濒危EN”和“易危VU” 的物种各3种,被评为 “近危NT”级别的物种有4种;鸟类被列为国家II级重点保护野生动物的有5种,被IUCN红色名录评估为“濒危EN”的物种有1种。本次调查补充更新了龙溪-虹口自然保护区地栖息鸟类名录,初步了解了保护区内地面活动大中型兽类和鸟类的物种组成和分布,为保护区建立野生动物红外相机常规监测和保护管理提供了基础数据。  相似文献   

14.
杨萍  杨永峰  杨宜男  程亚文  王立  王原 《生态学报》2023,43(22):9206-9217
鸟类栖息地会随着季节迁徙而改变,基于此对以珍稀濒危鸟类保护为主要目标的自然保护区进行动态分区管理,能够有效提高土地利用效率,协调生物多样性保护与其他生态系统服务功能利用。通过MaxEnt模型分析预测安徽升金湖国家级自然保护区鸟类繁殖季和越冬季的栖息地范围,并采用空间叠加分析方法得到动态分区方案。结果发现:繁殖季鸟类栖息地适宜性受到人口密度、丰水期土地利用类型、距居民点距离、距道路距离等环境因素的影响;越冬季鸟类受到距道路距离、人口密度、距枯水期水体距离、枯水期土地利用类型等环境因素的影响。运用ArcGIS水文工具分析出升金湖国家级自然保护区汇水单元作为其动态区划单元,根据鸟类栖息地季节性变化的特点结合分析结果叠加分析,将安徽升金湖国家级自然保护区划分为核心栖息地保护区、繁殖季栖息地保护区、越冬季栖息地保护区和一般控制区。核心栖息地保护区要进行全年严格保护,繁殖季栖息地保护区和越冬季栖息地保护区在相应鸟类栖息时段严格管控、非栖息时段可合理利用,一般控制区则全年可允许合理的行为活动。季节性动态分区方案注重解决安徽省升金湖国家级自然保护区生态环境保护和社区发展之间的矛盾问题,便于未来保护区生态保护规划决策的制定和实施,进一步丰富了以季节性栖息物种为主要保护对象的自然保护区的动态功能分区研究理论与方法体系,为制定提高自然保护区空间利用效率的生态管理策略提供了参考依据。综上,建议在升金湖国家级自然保护区生态环境保护和社区发展中,依据保护区季节性动态分区特征,实行分区管制,制定对应的生态环境保护和发展的措施。  相似文献   

15.
Quantifying how human-modified landscapes shape the distribution of biodiversity is critical for developing effective conservation strategies. To address this, we evaluated three hypotheses (habitat area, habitat configuration and matrix heterogeneity hypotheses) that predict responses of biodiversity to landscape structure in human-modified landscapes. We compared characteristics of landscape structure that influence taxonomic (TD), functional (FD), and phylogenetic (PD) dimensions of biodiversity of breeding birds in temperate forests. Relationships between biodiversity and landscape structure were assessed at multiple spatial scales for 20 forest interior sites in northeastern USA. We assessed if relationships with landscape structure were consistent among dimensions and assemblages of different groups (residents, migrants and all birds). Relationships between dimensions of biodiversity and landscape structure were more prevalent for FD and PD than for TD. Forest amount and configuration were rarely associated with any dimensions of biodiversity. In contrast, the identity of the matrix and heterogeneity of the landscape were frequently associated with biodiversity, but relationships differed among groups of birds. For example, FD of all birds was associated positively with landscape diversity but FD of residents was associated negatively with landscape diversity, suggesting that landscape diversity surrounding forests may increase overall FD of birds but that not all groups of species respond similarly. Indeed, biodiversity of migrants was only weakly related to landscape structure. Differences among relationships to landscape structure for bird groups and spatial scales suggests that management plans should consider local decisions within a regional framework to balance potentially conflicting needs of species groups in human-dominated landscapes.  相似文献   

16.
Farmland birds belong to the most endangered group of vertebrates in Europe. They are an important component of farmland biodiversity considering the numerous functions they perform (e.g. seed dispersal, improving germination, increasing gene flow, nutrient recycling, and pest control). Therefore, their decline imposes substantial risks on agricultural ecosystems. In general, farmland bird conservation includes land-use and management alterations leading to less-intensive farming and land-sparing for breeding habitats (e.g. agri-environment-climate schemes, and organic farming). However, theoretical concepts describing farmland biodiversity maintenance and applied conservation measures usually ignore the role of singular, often very small, natural or man-made elements in an agricultural landscape. These elements play a role in the populations of certain species, their biology and in the general species richness of farmland. Furthermore, the importance of these elements has never been empirically tested, which means that conservationists and practitioners are not aware of their measurable value for birds. Herein, we define and identify singular point elements in the agricultural landscape (SPELs) which are potentially important for breeding farmland birds. We also describe each SPEL and evaluate its importance for birds in farmland based on a systematic review of the available literature. Using a horizon-scanning technique, we then polled field ornithologists about their personal observations of birds in relation to SPELs and the evaluation of the potential roles of such structures for birds. We identified 17 SPELs that vary in naturalness and age: singular trees, singular shrubs, erratic boulders, puddles, electricity pylons, wind turbines, spiritual sites, hunting platforms, fence and border posts, wells, road signs, scarecrows, piles of manure, piles of brushwood/branches, piles of stones/debris, piles of lime, and haystacks. Analysis of the literature revealed knowledge gaps, because some SPELs are frequently mentioned in ecological studies (e.g. trees, shrubs, pylons), but others such as spiritual sites, stones, hunting platforms, wells, road signs, or piles of lime are ignored. Despite the fact that some authors incorporate the effects of some SPELs in their studies, little research to date has aimed to assess the impact of various SPELs on farmland bird species numbers and distribution. Horizon scanning revealed that ornithologists often observe birds on various SPELs and thus, attribute to SPELs many functions that are important for maintaining bird populations. Horizon scanning also highlighted the importance of SPELs for many declining bird species and suggested possible mitigation of negative changes in the agricultural landscape by retaining SPELs within fields. We suggest that a better understanding of the role of SPELs for farmland birds is required. We also recommend that SPELs are considered as a potential tool for the conservation of birds, and existing conservation programs such as agri-environment-climate schemes and organic farming should be updated accordingly. Finally, we suggest that SPELs are included in predictive models that evaluate habitat suitability for farmland biodiversity.  相似文献   

17.
There are few opportunities to evaluate the relative importance of landscape structure and dynamics upon biodiversity, especially in highly fragmented tropical landscapes. Conservation strategies and species risk evaluations often rely exclusively on current aspects of landscape structure, although such limited assumptions are known to be misleading when time-lag responses occur. By relating bird functional-group richness to forest patch size and isolation in ten-year intervals (1956, 1965, 1978, 1984, 1993 and 2003), we revealed that birds with different sensitivity to fragmentation display contrasting responses to landscape dynamics in the Brazilian Atlantic Forest. For non-sensitive groups, there was no time-lag in response: the recent degree of isolation best explains their variation in richness, which likely relates to these species’ flexibility to adapt to changes in landscape structure. However, for sensitive bird groups, the 1978 patch area was the best explanatory variable, providing evidence for a 25-year time-lag in response to habitat reduction. Time-lag was more likely in landscapes that encompass large patches, which can support temporarily the presence of some sensitive species, even when habitat cover is relatively low. These landscapes potentially support the most threatened populations and should be priorities for restoration efforts to avoid further species loss. Although time-lags provide an opportunity to counteract the negative consequences of fragmentation, it also reinforces the urgency of restoration actions. Fragmented landscapes will be depleted of biodiversity if landscape structure is only maintained, and not improved. The urgency of restoration action may be even higher in landscapes where habitat loss and fragmentation history is older and where no large fragment remained to act temporarily as a refuge.  相似文献   

18.
Semiarid Mediterranean areas patchily forested with Pinus halepensis Mill. are often affected by urbanisation plans, which influence the conservation of biodiversity in the remaining fragments. We assessed forest biodiversity in eleven Pinus halepensis patches of the municipality of Murcia (SE Spain), on the basis of the abundance, richness and conservation value of birds and woody flora. Under the hypothesis that biodiversity is conditioned by pine density, modulated by other patch features (age, physical substrate, surrounding land uses), mixed regression models were used to relate biodiversity indicators with environmental gradients, detected through principal component analyses (PCAs) performed on three sets of variables: landscape (L); habitat structure (H); and, stand development (S). PCA-L related patch size and connectivity to the abundance of typical woodland birds and to floral and bird species richness. PCA-H related shrub cover associated with Sylvia melanocephala Gmelin., to rock and dry grassland cover, a feature of moderately disturbed areas preferred by Lanius senator L. PCA-S associated taller trees and better physical conditions with canopy dwelling and soil probing bird species, respectively. The bird or plant conservation value of patches did not generally match their protection status, which was confirmed by the analysis of a larger sample of 36 natural patches. A negative relationship between floristic value and pine density suggests that reducing the density of reforestations can lead to more diverse and self-sustaining wooded formations. In contrast, conservation value for birds did not decrease with reforestation, stressing the need to use ornithological and floristic indexes as complementary assessment tools. The results seem useful for building a municipal network of reserves connecting higher status protected areas.  相似文献   

19.
ABSTRACT The islands of the Caribbean contain habitat of critical importance to a large number of endemic and resident birds, as well as many overwintering Neotropical migrants, and they rank as a globally outstanding conservation priority ecoregion and biodiversity hotspot. Considerable research from the region has focused on the ecology of permanent resident species, and these studies have had particular significance for threatened species management, especially parrot biology and conservation, but also for tropical community ecology in general. Work by ornithologists in the Caribbean has been instrumental in improving our understanding of the ecology of overwintering Neotropical migrants and in developing long‐term monitoring programs. Although Caribbean‐based studies of birds have resulted in significant contributions in many important areas of ecological research, there is a great need for additional research. Especially needed are studies with application to the management of resident species, and studies of how bird populations may be affected by pathogens, parasites, plants, and other types of biotic interactions. Studies focusing on how bird species and populations are affected by global climate change, and cumulative, landscape‐level changes in land use are also needed. Along with additional research, scientists have an important role to play in building capacity to prepare the next generation of biologists in the region who will need to address mounting challenges related to biodiversity protection. As with many conservation efforts, funding is a critical need for almost all organizations and agencies involved in research, conservation action, and capacity building in the West Indies.  相似文献   

20.
Protected areas are valuable in conserving tropical biodiversity, but an insufficient understanding of species diversity and distributions makes it difficult to evaluate their effectiveness. This is especially true on Borneo, a species rich island shared by three countries, and is particularly concerning for bats, a poorly known component of mammal diversity that may be highly susceptible to landscape changes. We reviewed the diversity, distributions and conservation status of 54 bat species to determine the representation of these taxa in Borneo’s protected areas, and whether these reserves complement each other in terms of bat diversity. Lower and upper bound estimates of bat species composition were characterised in 23 protected areas and the proposed boundaries of the Heart of Borneo conservation area. We used lower and upper bound estimates of species composition. By using actual inventories, species representation was highly irregular, and even if some reserves were included in the Heart of Borneo, the protected area network would still exhibit low complementarity. By inferring species presence from distributions, composition between most reserves was similar, and complementarity was much higher. Predicting species richness using abundance information suggested that bat species representation in reserves may lie between these two extremes. We recommend that researchers better sample biodiversity over the island and address the conservation threats faced in Borneo both within and outside protected areas. While the Heart of Borneo Initiative is commendable, it should not divert attention from other conservation areas.  相似文献   

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