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1.
We tested the effect of cultivation on butterfly (Nymphalidae: Charaxes) and beetle (Coleoptera: Scarabaeidae: Cetoniinae) species richness and abundance along a cultivation intensification gradient. Results showed significant differences in species richness and abundance between natural woodlands and cultivated landscapes with larger differences in areas of high cultivation intensity. The results indicate that natural woodland clearing for cultivation purposes has negative impacts on arthropod diversity, a situation more severe in highly intensified cultivated areas. Our results imply that mosaics of different land‐use units, each in a different phase of clearance‐cultivation‐abandonment‐recovery‐clearance cycle could counter the negative effects of cultivation intensity on arthropod diversity.  相似文献   

2.
A substantial proportion of the existing tree plantations has been established following clearing of native forests. This form of conversion has become widely unaccepted, and there are increasing demands to reverse it through ecological restoration. Yet, there is a lack of integrated knowledge on how best to restore. Here, we reviewed 68 studies to identify the main factors determining establishment success of regeneration of native woody species when restoring natural forests from plantation forests using active and passive approaches, beneath existing canopies, and following their removal. According to the evidence collected, herbivory, within‐gap position, soil properties, and ground cover type and structure had limited influence on regeneration, showing significant effects in less than 26% of cases in which their influence was tested. In contrast, spatial landscape configuration, overstorey structure, ground vegetation structure, overstorey composition, and climate and geomorphology had significant effects in 67, 47, 47, 52, and 63% of cases, respectively. Regeneration diversity and abundance increased with proximity to natural vegetation remnants and seed sources. Lower canopy and understorey stocking levels positively influenced regeneration, as did interventions to reduce them. Canopy cover reduction proved especially effective in warmer regions, in stands of broadleaved species, younger ages (<30 years), higher densities (>1,000 trees/ha), and taller canopies (>20 m). Restoration of native forests can be optimized by adopting interventions that prove most effective, and prioritizing more responsive stand types. However, the specific stand attributes and environmental factors described should be further studied to understand the mechanisms underlying their influence on regeneration.  相似文献   

3.
1. Aquatic macrophyte diversity and water quality of 55 ponds in western Japan were related to land use and morphometric variables to identify the environmental factors that sustain biodiversity and the spatial extent at which these factors operate. 2. The relevant spatial extent for floating‐leaved macrophyte richness (500 m from pond edge) was larger than that for submerged macrophyte occurrence (10, 75 and 100 m), whereas emergent macrophyte richness was best explained at much larger extents (1000 m). Total macrophyte richness was explained at the extent of 500, 750 and 1000 m. The extents relevant for explaining the physicochemical condition of pond water (100 and 250 m) were similar to those for submerged and floating‐leaved macrophytes, suggesting that these two growth forms are more sensitive to water quality compared to emergent macrophytes. 3. Diversity of all three growth forms and that of total macrophytes collectively were inversely related to turbidity and nutrient concentration; among the three growth forms, submerged macrophytes were most affected by water quality. 4. Negative relationships were found between the proportion of urban area and the diversity of the three growth forms and that of total macrophytes and water quality. Species richness of emergent, floating‐leaved and total macrophytes decreased with depth and increased with surface area up to about 5000 m2, above which it declined. 5. Urbanisation and enlargement of ponds were the two main factors that decreased aquatic macrophyte diversity in irrigation ponds. To alleviate the adverse effects of urban areas on aquatic macrophyte diversity, our results suggest that management efforts should focus on the creation of buffer zones within the relevant spatial extent from the pond edge.  相似文献   

4.
景观格局与生态过程的耦合研究:传承与创新   总被引:4,自引:0,他引:4  
景观格局与生态过程的耦合关系是景观生态学研究的核心主题,耦合研究的范围和程度需要进一步系统梳理。从景观格局与生态过程耦合的内涵、方法等方面,系统总结了当前两者研究的特点以及存在问题。进一步从格局-过程耦合基本理论传承与提升、研究方法现代化和多元化、研究尺度多样化、研究对象的扩展与集成、自然-人文-社会视角的耦合、格局-过程耦合的管理和调控等六个方面展望了未来学科发展方向。最后,提出了未来创新目标,如提高景观格局量化的准确性和针对性、辨明景观格局影响的尺度性、增强生态过程模拟的时效性等。  相似文献   

5.
Understanding the effects of anthropogenic disturbances on biodiversity is important for conservation prioritization. This study examined the effects of vegetation degradation on bird diversity in Abiata‐Shalla Lakes National Park, Ethiopia. We surveyed birds and vegetation structure between January and March 2015 in disturbed (impacted by settlement and agriculture) and undisturbed (not impacted) transects of two vegetation types (savannah woodland and gallery forest). We compared between disturbed and undisturbed transects at local (within vegetation types) and landscape (across vegetation types) levels: (a) avian species richness of the entire assemblage and feeding guilds and (b) species assemblage composition. We found significantly greater mean and total bird species richness of the entire assemblage and insectivore and granivore feeding guilds in the undisturbed transects, while the nectarivore guild was totally absent in the disturbed transects. We also found significant differences in bird species assemblage composition between the disturbed and undisturbed transects both within and across the vegetation types, and bird species assemblage composition at the landscape level was positively correlated with tree abundance and understorey vegetation height. In conclusion, our results demonstrate and add to the increasing body of evidence concerning the adverse effects of human‐induced vegetation change on bird diversity.  相似文献   

6.
In order to guarantee the safety of genetically modified (GM) soybean crops, it is important to assess the potential toxicity of their expressed insecticidal proteins to non‐target organisms. In the present study, the effects of the GM soybean Insulin‐like Growth Factor (IGF), which is tolerant to the herbicide glufosinate, on plant‐dwelling non‐target insects and arachnids were evaluated in soybean agroecosystems. For comparison, the non‐GM parental cultivar of soybean Gwangan‐kong was used as a control. Data were collected in 2016 and 2017 via surveying at Ochang and Jeonju, Korea. In total, 13,031 individual insects and arachnids, representing 64 families in 11 orders, were captured during the study. Firstly, the results indicate that the GM soybean IGF did not negatively affect plant‐dwelling non‐target insects and arachnids. However, the numbers of captured individuals on both IGF and Gwangan‐kong were higher at Ochang in 2017. The occurrence of insect pests, natural enemies, and other insects differed significantly according to region, region and survey year, and survey year, respectively. In addition, the dominance, diversity, evenness, and richness indices for the collected insects varied significantly among the regions and survey years regardless of soybean variety. The score from PROXSCAL multidimensional scaling using combined data showed that insects and arachnids in different natural environments were separated by their cultivation regions and years irrespective of soybean cultivars.  相似文献   

7.
Landscape features notoriously affect spatial patterns of biodiversity. For instance, in dendritic ecological networks (such as river basins), dendritic connectivity has been proposed to create unique spatial patterns of biodiversity. Here, we compared genetic datasets simulated under a lattice‐like, a dendritic and a circular landscape to test the influence of dendritic connectivity on neutral genetic diversity. The circular landscape had a level of connectivity similar to that of the dendritic landscape, so as to isolate the influence of dendricity on genetic diversity. We found that genetic diversity and differentiation varied strikingly among the three landscapes. For instance, the dendritic landscape generated higher total number of alleles and higher global Fst than the lattice‐like landscape, and these indices also varied between the dendritic and the circular landscapes, suggesting an effect of dendricity. Furthermore, in the dendritic landscape, allelic richness was higher in highly connected demes (e.g. confluences in rivers) than in low‐connected demes (e.g. upstream and downstream populations), which was not the case in the circular landscape, hence confirming the major role of dendricity. This led to bell‐shaped distributions of allelic richness along an upstream–downstream gradient. Conversely, genetic differentiation (Fst) was lower in highly than in low‐connected demes (which was not observed in circular landscape), and significant patterns of isolation by distance (IBD) were also observed in the dendritic landscape. We conclude that in dendritic networks, the combined influence of dendricity and connectivity generates unique spatial patterns of neutral genetic diversity, which has implications for population geneticists and conservationists.  相似文献   

8.
9.
An important aspect of biodiversity is the relative importance of species in the functioning of ecosystems; this is particularly so for the soil biota which regulate organic matter and nutrient dynamics in soil. This paper explores some of the relationships between biodiversity and ecosystem processes, using the example of the nearctic earthworm fauna in the glacial refugium of the southern USA. Competitive exclusion of nearctic earthworm species by exotic species has been postulated but there is little direct evidence of it; habitat alteration is the likely cause of native species decline. Reduced earthworm diversity may or may not strongly affect certain ecosystem processes, but more diverse assemblages may more effectively exploit soil resources and influence a wider array of processes. Nearctic species may be better adapted than exotics to local conditions and thus more strongly influence ecosystem processes. Earthworm communities provide a clear case for the union of functional and taxonomic biodiversity studies, because of the recognized ecological strategies of many species. However, some nearctic taxa may deviate from these strategies. Earthworms utilize course woody debris in forests both as a refuge and a resource, while enhancing the decomposition of wood. Management strategies to maintain or increase biodiversity of soil biota should include residual wood on the forest floor. An important task for ecosystem management is to restore biodiversity in degraded ecosystems; introduction programmes and techniques such as periodic burning may increase the abundance and diversity of native earthworm species. Whole ecosystem conservation and management are probably the most practical ways to conserve biodiversity generally and may be the only ways to maintain soil biodiversity.  相似文献   

10.
The loss and degradation of woody vegetation in the agricultural matrix represents a key threat to biodiversity. Strategies for habitat restoration in these landscapes should maximize the biodiversity benefit for each dollar spent in order to achieve the greatest conservation outcomes with scarce funding. To be effective at scale, such strategies also need to account for the opportunity cost of restoration to the farmer. Here, we critique the Whole‐of‐Paddock Rehabilitation program, a novel agri‐environment scheme which seeks to provide a cost‐effective strategy for balancing habitat restoration and livestock grazing. The scheme involves the revegetation of large (minimum 10 ha) fields, designed to maximize biodiversity benefits and minimize costs while allowing for continued agricultural production. The objectives and design of the scheme are outlined, biodiversity and production benefits are discussed, and we contrast its cost‐effectiveness with alternative habitat restoration strategies. Our analysis indicates that this scheme achieves greater restoration outcomes at approximately half the cost of windbreak‐style plantings, the prevailing planting configuration in southeastern Australia, largely due to a focus on larger fields, and the avoidance of fencing costs through the use of existing farm configuration and infrastructure. This emphasis on cost‐effectiveness, the offsetting of opportunity costs through incentive payments, and the use of a planting design that seeks to maximize biodiversity benefits while achieving production benefits to the farmer, has the potential to achieve conservation in productive parts of the agricultural landscape that have traditionally been “off limits” to conservation.  相似文献   

11.
全球变化对土壤动物多样性的影   总被引:1,自引:0,他引:1  
吴廷娟 《生态学杂志》2013,24(2):581-588
陆地生态系统由地上和地下两部分组成,二者相互作用共同影响生态系统过程和功能.土壤动物在生物地球化学循环方面起着重要作用.随着人们对土壤动物在生态系统过程中重要性的认识,越来越多的研究表明全球变化对土壤动物多样性产生深刻影响.土地利用方式的改变、温度增加和降雨格局的改变能直接影响土壤动物多样性.CO2浓度和氮沉降的增加主要通过影响植物群落结构、组成和化学成分对土壤动物多样性产生间接影响.不同环境因子之间又能相互作用共同影响土壤动物多样性.了解全球变化背景下不同驱动因子及其交互作用对土壤动物多样性的影响,有助于更好地预测未来土壤动物多样性及相关生态学过程的变化.  相似文献   

12.
林业活动和森林片断化对甲虫多样性的影响及保护对策   总被引:7,自引:3,他引:4  
森林片断化是造成生物多样性丧失的主要原因之一,而林业活动是导致森林片断化的重要因素,同时也在森林恢复中起重要作用。本文从小尺度、局域尺度以及生物地理尺度(大尺度)3个生态尺度分析林业活动和森林片断化对甲虫多样性的影响。在小尺度下,林业活动能够通过改变森林生境或微生境的类型和特性而影响甲虫物种分布。在局域尺度下,林业活动(尤其是森林砍伐)往往能提高许多甲虫类群(如步甲)的物种丰富度(α多样性),这主要与来自周围环境物种扩散以及保留了若干耐受新环境能力较强的森林物种有关;然而,对森林生境依赖性很强的特有种受到了森林片断化的负面影响,面临局域种群灭绝的危险。在生物地理尺度下,林业活动(伐木或森林恢复)使森林生境单一化、异质性降低,从而导致对森林生境变化敏感的物种种群数量降低甚至灭绝。基于以上结果,可以归纳出3个基本原则用于指导林业管理,既能保证林业经济收益,又能维持森林生物多样性。首先,保留大面积的原始森林作为特有种的栖息环境基地,为这些物种在将来森林恢复后重新定居提供资源;其次,由于保护区内原始森林面积有限,且所代表的生境类型有限,所以发展依据自然干扰模式的新伐木方法十分必要;最后,依据自然规律(如火灾)进行森林恢复和天然演替,避免森林的单一化,丰富森林生境类型。  相似文献   

13.
14.
第5届国际生态恢复学会大会于2013年10月6—11日在美国威斯康星州麦迪逊召开.来自50多个国家的约1200位代表参加了本次大会,讨论了生态恢复不同领域的最新进展.会议中关于生态恢复评价的探讨主要从生态恢复评价指标体系的建立、生态恢复的评价方法、生态恢复监测与动态评价三方面展开.会议强调了生态恢复评价在生态恢复过程中的重要地位,关注了生态恢复评价研究中面临的挑战.对我国生态恢复评价研究主要有以下启示: 1)加强构建全面、综合的评价指标体系,注重评价过程的多方参与;2)注重生态恢复评价的尺度效应与尺度转换研究;3)拓展3S技术在生态恢复评价中的应用,促进生态恢复动态监测的发展;4)积极开展国际交流合作,提升我国生态恢复研究的国际影响力.
  相似文献   

15.
There exist a number of key macroecological patterns whose ubiquity suggests that the spatio‐temporal structure of ecological communities is governed by some universal mechanisms. The nature of these mechanisms, however, remains poorly understood. Here, we probe spatio‐temporal patterns in species richness and community composition using a simple metacommunity assembly model. Despite making no a priori assumptions regarding biotic spatial structure or the distribution of biomass across species, model metacommunities self‐organise to reproduce well‐documented patterns including characteristic species abundance distributions, range size distributions and species area relations. Also in agreement with observations, species richness in our model attains an equilibrium despite continuous species turnover. Crucially, it is in the neighbourhood of the equilibrium that we observe the emergence of these key macroecological patterns. Biodiversity equilibria in models occur due to the onset of ecological structural instability, a population‐dynamical mechanism. This strongly suggests a causal link between local community processes and macroecological phenomena.  相似文献   

16.
Climate and land‐use change jointly affect the future of biodiversity. Yet, biodiversity scenarios have so far concentrated on climatic effects because forecasts of land use are rarely available at appropriate spatial and thematic scales. Agent‐based models (ABMs) represent a potentially powerful but little explored tool for establishing thematically and spatially fine‐grained land‐use scenarios. Here, we use an ABM parameterized for 1,329 agents, mostly farmers, in a Central European model region, and simulate the changes to land‐use patterns resulting from their response to three scenarios of changing socio‐economic conditions and three scenarios of climate change until the mid of the century. Subsequently, we use species distribution models to, first, analyse relationships between the realized niches of 832 plant species and climatic gradients or land‐use types, respectively, and, second, to project consequent changes in potential regional ranges of these species as triggered by changes in both the altered land‐use patterns and the changing climate. We find that both drivers determine the realized niches of the studied plants, with land use having a stronger effect than any single climatic variable in the model. Nevertheless, the plants' future distributions appear much more responsive to climate than to land‐use changes because alternative future socio‐economic backgrounds have only modest impact on land‐use decisions in the model region. However, relative effects of climate and land‐use changes on biodiversity may differ drastically in other regions, especially where landscapes are still dominated by natural or semi‐natural habitat. We conclude that agent‐based modelling of land use is able to provide scenarios at scales relevant to individual species distribution and suggest that coupling ABMs with models of species' range change should be intensified to provide more realistic biodiversity forecasts.  相似文献   

17.
Determining the mechanisms that underlie species distributions and assemblages is necessary to effectively preserve biodiversity. This cannot be accomplished by examining a single taxonomic group, as communities comprise a plethora of interactions across species and trophic levels. Here, we examine the patterns and relationships among plant, mammal, and bird diversity in Madagascar, a hotspot of biodiversity and endemism, across taxonomic, phylogenetic, and functional axes. We found that plant community diversity and structure are shaped by geography and climate, and have significant influences on the taxonomic, phylogenetic and functional diversity of mammals and birds. Patterns of primate diversity, in particular, were strongly correlated with patterns of plant diversity. Furthermore, our findings suggest that plant and animal communities could become more phylogenetically and functionally clustered in the future, leading to homogenization of the flora and fauna. These results underscore the importance and need of multi‐taxon approaches to conservation, given that even small threats to plant diversity can have significant cascading effects on mammalian and avian community diversity, structure, and function.  相似文献   

18.
The global decline of corals has created an urgent need for effective, science‐based methods to augment coral populations and restore important ecosystem functions. To meet this challenge, the field of coral restoration has rapidly evolved over the past decade. However, despite widespread efforts to outplant corals and monitor survivorship, there is a shortage of information on the effects of coral restoration on reef communities or important ecosystem functions. To fill this knowledge gap, we examined the effects of restoration on three major criteria: diversity, community structure, and ecological processes. We conducted surveys of four restored sites in the Florida Keys ranging in restoration effort (500–2,300 corals outplanted) paired with surveys of nearby, unmanipulated control sites. Coral restoration successfully enhanced coral populations, increasing coral cover 4‐fold, but manifested in limited differences in coral and fish communities. Some restored sites had higher abundance of herbivorous fish, rates of herbivory, or more juvenile‐sized corals, but these effects were limited to individual reefs. Damselfish were consistently more abundant at restored compared to control sites. Despite augmenting target coral populations, 3 years of coral restoration has not facilitated many of the positive feedbacks that help reinforce coral success. In a time of increasingly frequent disturbances, it is urgent we hasten the speed at which reefs recover important ecological processes, such as herbivory and nutrient cycling, that make reefs more resistant and resilient if we are to achieve long‐term restoration success.  相似文献   

19.
20.
This review focuses on recent ecological changes in the Sahel. While other recent reviews focused mainly on agricultural changes, remote sensing, and the evolution and distribution of biodiversity, no review focused on ecological changes over time although these changes needed to be summarized to better understand the recent and often dramatic species declines across the Sahel during the last half century. Therefore, I conducted a literature review to summarize these changes, in particular changes to (i) land‐use and land‐cover, (ii) wetlands, (iii) plants, (iv) birds, especially large and migratory birds and (v) large mammals. The main conclusion is that the exceptionally severe Sahel drought in the late 20th century was extremely detrimental to both human society and nature, but thereafter, rainfall, agricultural productivity and human welfare increased again. As human populations and their ecological footprint increased dramatically, the Sahel's biodiversity continued to become more and more impoverished, whereby woody vegetation, migratory birds, and large birds and mammals suffered particularly severe declines. Besides the agricultural expansion, the other main reasons for these declines are wetland conversions, increased fire frequency, overharvesting, persecution, poisoning and death caused by human artefacts and disturbance. More effective protected areas are urgently needed, which could also generate much needed tourism revenue.  相似文献   

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