首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
    
Understanding the roles of ecological drivers in shaping biodiversity is fundamental for conservation practice. In this study, we explored the effects of elevation, conservation status, primary productivity, habitat diversity and anthropogenic disturbance (represented by human population density and birding history) on taxonomic, phylogenetic and functional avian diversity in a subtropical landscape in southeastern China. We conducted bird surveys using 1‐km transects across a total of 30 sites, of which 10 sites were located within a natural reserve. Metrics of functional diversity were calculated based on six functional traits (body mass, clutch size, dispersal ratio, sociality, diet and foraging stratum). We built simultaneous autoregression models to assess the association between the ecological factors and diversity of the local avian communities. Local avian diversity generally increased with increasing habitat diversity, human population density and primary productivity. We also detected phylogenetic and functional clustering in these communities, suggesting that the avian assemblages were structured mainly by environmental filtering, rather than interspecific competition. Compared with sites outside the natural reserve, sites within the natural reserve had relatively lower avian diversity but a higher level of phylogenetic heterogeneity.  相似文献   

2.
Determinants of avian species richness at different spatial scales   总被引:9,自引:1,他引:9  
ABSTRACT. Studies of factors influencing avian biodiversity yield very different results depending on the spatial scale at which species richness is calculated. Ecological studies at small spatial scales (plot size 0.0025–0.4 km2) emphasize the importance of habitat diversity, whereas biogeographical studies at large spatial scales (quadrat size 400–50,000 km2) emphasize variables related to available energy such as temperature. In order to bridge the gap between those two approaches the bird atlas data set of Lake Constance was used to study factors determining avian species diversity at the intermediate spatial scales of landscapes (quadrat size 4–36 km2). At these spatial scales bird species richness was influenced by habitat diversity and not by variables related to available energy probably because, at the landscape scale, variation in available energy is small. Changing quadrat size between 4 and 36 km2, but keeping the geographical extension of the study constant resulted in profound changes in the degree to which the amount of different habitat types was correlated with species richness. This suggests that high species diversity is achieved by different management regimes depending on the spatial scale at which species richness is calculated. However, generally, avian species diversity seems to be determined by spatial heterogeneity at the corresponding spatial scale. Thus, protecting the diversity of landscapes and ecosystems appears to ensure also high levels of species diversity.  相似文献   

3.
    
Vegetation complexity is an important predictor of animal species diversity. Specifically, taller vegetation should provide more potential ecological niches and thus harbor communities with higher species richness and functional diversity (FD). Resource use behavior is an especially important functional trait because it links species to their resource base with direct relevance to niche partitioning. However, it is unclear how exactly the diversity of resource use behavior changes with vegetation complexity. To address this question, we studied avian FD in relation to vegetation complexity along a continental‐scale vegetation gradient. We quantified foraging behavior of passerine birds in terms of foraging method and substrate use at 21 sites (63 transects) spanning 3,000 km of woodlands and forests in Australia. We also quantified vegetation structure on 630 sampling points at the same sites. Additionally, we measured morphological traits for all 111 observed species in museum collections. We calculated individual‐based, abundance‐weighted FD in morphology and foraging behavior and related it to species richness and vegetation complexity (indexed by canopy height) using structural equation modeling, rarefaction analyses, and distance‐based metrics. FD of morphology and foraging methods was best predicted by species richness. However, FD of substrate use was best predicted by canopy height (ranging 10–30 m), but only when substrates were categorized with fine resolution (17 categories), not when categorized coarsely (8 categories). These results suggest that, first, FD might increase with vegetation complexity independently of species richness, but whether it does so depends on the studied functional trait. Second, patterns found might be shaped by how finely we categorize functional traits. More complex vegetation provided larger \"ecological space\" with more resources, allowing the coexistence of more species with disproportionately more diverse foraging substrate use. We suggest that the latter pattern was driven by nonrandom accumulation of functionally distinct species with increasing canopy height.  相似文献   

4.
    
《Current biology : CB》2023,33(6):1153-1161.e4
  相似文献   

5.
6.
田长城  蒋学龙  彭华  范朋飞  周守标 《生态学报》2007,27(10):4002-4010
无量山是黑长臂猿景东亚种的唯一分布区,现栖息着98群500余只黑长臂猿。长臂猿是典型的树栖性灵长类动物,通过对无量山西坡大寨子地区250个样方的调查,分析了随海拔梯度升高,黑长臂猿栖息地植被乔木层物种多样性和结构的变化情况。共记录乔木111种,隶属于33科;木质藤本23种,隶属于18科。其中优势科主要有樟科(Lauraceae)、木兰科(Magnoliaceae)、壳斗科(Fagaceae)、山茶科(Theaceae)和杜鹃花科(Ericaceae)。根据不同海拔乔木层物种组成的差异,该区可划分为半湿润常绿阔叶林(2100~2300m)和中山湿性常绿阔叶林(2400~2600m)两种植被类型。多样性指数(Shannon-Wiener指数)随海拔升高在两种植被类型中均呈下降趋势;均匀度指数(Pielou指数)在半湿润常绿阔叶林中呈下降趋势,在中山湿性常绿阔叶林中无明显变化。半湿润常绿阔叶林中,阳坡的乔木物种多样性低于阴坡;而阳坡物种多样性在两种植被类型间差异显著。随着海拔的升高,乔木层的平均高度和上层乔木(Ⅰ层)的比例均逐渐降低,但下层乔木却呈上升趋势。6种优势乔木树种的种群年龄结构分析表明,该区植被的乔木层呈现稳定增长的趋势。  相似文献   

7.
    
The biotic resistance theory relates invader success to species richness, and predicts that, as species richness increases, invasibility decreases. The relationship between invader success and richness, however, seems to be positive at large scales of analysis, determined by abiotic constraints, and it is to be expected that it is negative at small scales, because of biotic interactions. Moreover, the negative relationship at small scales would be stronger within species of the same functional group, because of having similar resource exploitation mechanisms. We studied the relationship between the cover of a worldwide invader of grasslands, Hieracium pilosella L., and species richness, species diversity and the cover of different growth forms at two different levels of analysis in 128 sites during the initial invasion process in the Fuegian steppe, Southern Patagonia, Argentina. At regional level, the invader was positively correlated to total (r = 0.28, P = 0.003), exotic (r = 0.273, P = 0.004), and native species richness (r = 0.210, P = 0.026), and to species diversity (r = 0.193, P = 0.041). At community level, we found only a weak negative correlation between H. pilosella and total richness (r = ?0.426, P = 0.079) and diversity (r = ?0.658, P = 0.063). The relationship between the invader and other species of the same growth form was positive both at regional (r = 0.484, P < 0.001) and community (r = 0.593, P = 0.012) levels. Consequently, in the period of establishment and initial expansion of this exotic species, our results support the idea that invader success is related to abiotic factors at large scales of analysis. Also, we observed a possible sign of biotic constraint at community level, although this was not related to the abundance of species of the same growth form.  相似文献   

8.
  总被引:2,自引:0,他引:2  
Aim Small mammal species richness and relative abundance vary along elevational gradients, but there are different patterns that exist. This study reports the patterns of distribution and abundance of small mammals along the broader elevational gradient of Mt. Qilian range. Location The study was conducted in the Mt. Qilian range, north‐western China, from June to August 2001. Methods Removal trapping was conducted using a standardized technique at 7 sites ranging between 1600 and 3900 m elevation within three transects. Correlation, regression and graphical analyses were used to evaluate the diversity patterns along this elevational gradient. Results In total, 586 individuals representing 18 nonvolant small mammal species were collected during 20 160 trap nights. Species composition was different among the three transects with 6 (33%) of the species found only within one transect. Elevational distribution and relative abundance of small rodents showed substantial spatial variation, with only 2 species showing nonsignificant capture frequencies across elevations. Despite these variations, some general patterns of elevational distribution emerged: humped‐shape relationships between species diversity and elevation were noted in all three transects with diversity peaks at middle elevations. In addition, relative abundance was negatively correlated with elevation. Conclusions Results indicate that maximum richness and diversity of nonvolant small mammals occurred at mid‐elevations where several types of plants reached their maximum diversity and primary productivity, and where rainfall and humidity reached a maximum. It is demonstrated that the mid‐elevation bulge is a general feature of at least a large portion of the biota on the Mt. Qilian range.  相似文献   

9.
General circulation models (GCM) predict that increasing levels of atmospheric carbon dioxide (CO2) and other greenhouse gases will lead to dramatic changes in climate. It is known that the spatial variability of species richness over continental spatial scales is strongly correlated with contemporary climate. Assuming that this relationship between species richness and climate persists under conditions of increased CO2, what changes could we expect to occur in terms of species richness? To address this question, I used observed relationships between contemporary richness and climate, coupled with climate projections from five GCM, to project these future changes. These models predict that the richness of vertebrate ectotherms will increase over most of the conterminous United States. Mammal and bird richness are predicted to decrease in much of the southern US and to increase in cool, mountainous areas. Woody plant richness is likely to increase throughout the North and West and to decrease in the southwestern deserts. These projections represent changes that are likely to occur over long time scales (millennia); short-term changes are expected to be mainly negative.  相似文献   

10.
    
Biodiversity conservation in human-inhabited landscapes is increasingly gaining attention due to the global decline of species. Understanding the impact of human activities on avian functional ecology is becoming increasingly important as habitats are transformed. We assessed the influence of habitat fragmentation on avian functional diversity (FD), focusing on metrics like functional richness (FRic), evenness (FEve) and divergence (FDiv). We calculated the FRic, FEve and FDiv across habitats using ‘fundiversity’ R package. We also calculated the Enhanced Vegetation Index (EVI) and estimated land-use cover of the study area from Landsat 8 images. We observed higher FD in minimally disturbed habitats, where among the habitats, woodland had high FD while human settlement had low. This supports the intermediate disturbance hypothesis, which suggests that moderate disturbance can increase species diversity. Our findings emphasise the pivotal role of fragmented habitats in shaping avian functional ecology, with environmental variables such as the EVI influencing diversity across habitats. Hence, we promote sustainable conservation connectivity, proper land management practices and conservation-friendly agricultural practices for sustainable biodiversity conservation.  相似文献   

11.
Research on island species–area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity–area relationship (IDAR). Here, we undertake the first comparative evaluation of IDARs at the global scale using 51 avian archipelagic data sets representing true and habitat islands. Using null models, we explore how richness-corrected functional and phylogenetic diversity scale with island area. We also provide the largest global assessment of the impacts of species introductions and extinctions on the IDAR. Results show that increasing richness with area is the primary driver of the (non-richness corrected) IPDAR and IFDAR for many data sets. However, for several archipelagos, richness-corrected functional and phylogenetic diversity changes linearly with island area, suggesting that the dominant community assembly processes shift along the island area gradient. We also find that archipelagos with the steepest ISARs exhibit the biggest differences in slope between IDARs, indicating increased functional and phylogenetic redundancy on larger islands in these archipelagos. In several cases introduced species seem to have ‘re-calibrated’ the IDARs such that they resemble the historic period prior to recent extinctions.  相似文献   

12.
中国阿勒泰地区位于新疆北部, 与哈萨克斯坦、俄罗斯、蒙古国交界, 该区包含阿尔泰山及山前荒漠和绿洲, 属于全球200个生物多样性最丰富和最具代表性生态区之一的阿尔泰-萨彦岭生物热点地区。阿勒泰地区生境多样, 鸟类物种资源丰富。尽管以往曾在阿勒泰地区进行过一些鸟类调查, 但对于该地区不同景观和生境类型中鸟类物种丰富度和分布尚无详尽报道。本文通过2013-2016年在中国境内阿尔泰山及山前平原地区对不同生境类型中的鸟类进行实地调查, 并总结文献资料及观鸟爱好者的记录数据, 重新整理了阿勒泰地区鸟类名录及地理分布, 分析了鸟类的物种组成、区系成分; 通过鸟类分布位点数据, 选取气候、土地覆被类型、人类足迹指数及地形共4类环境因子作为自变量建立MaxEnt生态位模型, 通过模拟77种鸟类的适宜分布区并叠加分布图层, 获得了阿勒泰地区的鸟类物种丰富度分布格局。结果表明: 阿勒泰共记录鸟类344种, 隶属19目55科149属, 其中雀形目163种。在垂直海拔带上, 鸟类物种数分别为高山裸岩带24种, 高山草甸带35种, 山地森林草原带172种, 低山灌木带130种, 荒漠草原带84种, 平原绿洲带173种, 以及各海拔带的湿地与水域生境中水鸟92种; 在区系成分上, 以北方型鸟类为主(170种, 占49.4%), 其次为广布种(93种, 占27.0%)。阿尔泰山地的鸟类区系呈现出西伯利亚动物区系特征, 山前平原地区呈现蒙新区分布特征, 因此, 阿勒泰地区动物地理区系属于古北界欧洲-西伯利亚亚界阿尔泰-萨彦岭区阿尔泰亚区; 山前平原地区属于古北界中亚亚界蒙新区西部荒漠亚区。MaxEnt模型推测阿勒泰地区山前平原绿洲地区、山地森林草原带和低山灌木带具有较高的鸟类物种丰富度, 尤其是额尔齐斯河流域下游的绿洲带宽阔, 鸟类物种丰富, 而高山区和荒漠生境中鸟类物种相对较少。模型预测的结果与实际调查情况相符。阿勒泰地区应采用生态友好的经济发展策略, 加强对乔木和灌木的保护, 这有助于维持较高的鸟类物种多样性。此外, 降低生境破碎化不仅对该地区物种保护有重要作用, 也对维持阿尔泰-萨彦岭生物热点地区的山地鸟类多样性有重要意义。  相似文献   

13.
14.
    
Aim In recent years evidence has accumulated that plant species are differentially sorted from regional assemblages into local assemblages along local‐scale environmental gradients on the basis of their function and abiotic filtering. The favourability hypothesis in biogeography proposes that in climatically difficult regions abiotic filtering should produce a regional assemblage that is less functionally diverse than that expected given the species richness and the global pool of traits. Thus it seems likely that differential filtering of plant traits along local‐scale gradients may scale up to explain the distribution, diversity and filtering of plant traits in regional‐scale assemblages across continents. The present work aims to address this prediction. Location North and South America. Methods We combine a dataset comprising over 5.5 million georeferenced plant occurrence records with several large plant functional trait databases in order to: (1) quantify how several critical traits associated with plant performance and ecology vary across environmental gradients; and (2) provide the first test of whether the woody plants found within 1° and 5° map grid cells are more or less functionally diverse than expected, given their species richness, across broad gradients. Results The results show that, for many of the traits studied, the overall distribution of functional traits in tropical regions often exceeds the expectations of random sampling given the species richness. Conversely, temperate regions often had narrower functional trait distributions than their smaller species pools would suggest. Main conclusion The results show that the overall distribution of function does increase towards the equator, but the functional diversity within regional‐scale tropical assemblages is higher than that expected given their species richness. These results are consistent with the hypothesis that abiotic filtering constrains the overall distribution of function in temperate assemblages, but tropical assemblages are not as tightly constrained.  相似文献   

15.
: 2014年3月21日-5月9日,采用样线法与定点观察法对沈阳市周边26个重要生态保护地春季迁徙期鸟类多样性进行了调查。共记录鸟类16目40科94种。其中,国家Ⅰ级重点保护鸟类2种;国家Ⅱ级重点保护鸟类4种。居留型组成以夏候鸟和旅鸟为主,共占记录鸟类物种总数的77.7%。区系组成以古北界种为主,占74.5%。生态型中鸣禽最多,占36.2%。不同调查样地的鸟类组成与多样性指数存在较大差异,水库湿地鸟类数量最多;湿地公园物种丰富度最高;森林生态系统鸟类多样性较高;沙地生境鸟类多样性较低。调查发现部分生态保护地存在人为干扰程度较大、生态破坏严重、生境类型高度单一等生态问题。针对相应的生态保护地应进一步加强生态环境治理,为鸟类生存提供良好的栖息环境。  相似文献   

16.
Aim We examined the relationship between species richness and morphological complexity of terrestrial mammal communities along an elevational gradient. Location The gradient is in the Sonoran Desert in Southern California and extends from a sand dune habitat near sea level to coniferous forest ending at >2600 m. Methods Morphological diversity, characterized by both size and shape of coexisting mammal species, was estimated within and between sites from projections of variables on principal components axes. Similarities among species were calculated as Euclidean distances. To tease apart size and shape, we constructed two principal component analyses: one based on log-transformed original measurements, the other on log-transformed proportional shape variables. To test whether species number accounted for the morphological diversity at each site we designed two null models. The models generated were random communities generated from the forty-two-species pool. Indices of morphological diversity for real communities were compared with the results of 500 simulations of each null model. Results Species richness varied along the gradient, peaking in the mid-elevation agave-ocotillo habitat. Morphological diversity of shapes and sizes correlated strongly with species richness. Locomotor, tooth, and skull traits were all important in distinguishing among species. Main conclusions Two important patterns emerged: (1) diversity of both sizes and of shapes of species within communities correlated positively with species number, and both sets of variables behaved similarly across this gradient; (2) the most species rich sites were not composed of specialists on these best places, but rather, a community of species derived from overlapping faunal groups.  相似文献   

17.
The reservoirs studied are located on a very important migratory flyway in the Mexican Central Plateau. The survey included the waterfowl, macrophytes and physico-chemical parameters of three localities visited on ten occasions during a 1-year period. A total of 23 waterfowl species were observed: 6 transients, 10 winter visitants, and 7 residents. A period of increased richness was detected in winter, when migratory species arrive at the reservoirs. A canonical correspondence analysis showed segregation patterns of the species for the use of the space. Migratory ducks occurred in Umécuaro, where there is a larger variety of macrophytes and eutrophication occurs. Loma Caliente was the area with less eutrophication and was not preferred by ducks. Gallinago gallinago and Ardea herodias were the species with the highest frequency of occurrence, while the Effluent was the preferred site of resident species. Although the reservoirs studied are small, they are suitable for a significative number of species to be considered as a waterfowl protection and conservation zone.  相似文献   

18.
19.
  总被引:6,自引:0,他引:6  
Rapid anthropogenic climate change is already affecting species distributions and ecosystem functioning worldwide. We applied niche-based models to analyse the impact of climate change on tree species and functional diversity in Europe. Present-day climate was used to predict the distributions of 122 tree species from different functional types (FT). We then explored projections of future distributions under one climate scenario for 2080, considering two alternative dispersal assumptions: no dispersal and unlimited dispersal. The species-rich broadleaved deciduous group appeared to play a key role in the future of different European regions. Temperate areas were projected to lose both species richness and functional diversity due to the loss of broadleaved deciduous trees. These were projected to migrate to boreal forests, thereby increasing their species richness and functional diversity. Atlantic areas provided an intermediate case, with a predicted reduction in the numbers of species and occasional predicted gains in functional diversity. This resulted from a loss in species within the broadleaved deciduous FT, but overall maintenance of the group. Our results illustrate the fact that both species-specific predictions and functional patterns should be examined separately in order to assess the impacts of climate change on biodiversity and gain insights into future ecosystem functioning.  相似文献   

20.
外来种入侵与物种多样性   总被引:18,自引:2,他引:18  
在入侵生态学研究方面 ,物种多样性与生物入侵之间的关系已成为当前研究和争论的焦点。自Elton的经典假说提出以来 ,物种丰富度高的群落比物种贫乏的群落更能抵抗外来种入侵的观点得到广泛接受。一些理论模型和多样性处理实验支持了该假说。但现在越来越多的野外观测和实验研究开始对这一经典假说提出异议 ,甚至反对。同时 ,在入侵生态学广泛受到关注的今天 ,大量的实验研究也提出了一些新的观点。本文对Elton经典假说提出以来全球有关物种多样性与生物入侵关系的主要研究及其观点进行了评述 ,以期为我国有关研究工作的开展提供参考。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号