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1.
Aim  In response to a recent paper suggesting the failure of ecological niche models to predict between native and introduced distributional areas of fire ants ( Solenopsis invicta ), we sought to assess methodological causes of this failure.
Location  Ecological niche models were developed on the species' native distributional area in South America, and projected globally.
Methods  We developed ecological niche models based on six different environmental data sets, and compared their respective abilities to anticipate the North American invasive distributional area of the species.
Results  We show that models based on the 'bioclimatic variables' of the WorldClim data set indeed fail to predict the full invasive potential of the species, but that models based on four other data sets could predict this potential correctly.
Main conclusions  The difference in predictive abilities appears to centre on the complexity of the environmental variables involved. These results emphasize important influences of environmental data sets on the generality and ability of ecological niche models to anticipate novel phenomena, and offer a simpler explanation for the lack of predictive ability among native and invaded distributional areas than that of niche shifts.  相似文献   

2.
Niche conservatism and niche divergence are both important ecological mechanisms associated with promoting allopatric speciation across geographical barriers. However, the potential for variable responses in widely distributed organisms has not been fully investigated. For allopatric sister lineages, three patterns for the interaction of ecological niche preference and geographical barriers are possible: (i) niche conservatism at a physical barrier; (ii) niche divergence at a physical barrier; and (iii) niche divergence in the absence of a physical barrier. We test for the presence of these patterns in a transcontinentally distributed snake species, the common kingsnake ( Lampropeltis getula ), to determine the relative frequency of niche conservatism or divergence in a single species complex inhabiting multiple distinct ecoregions. We infer the phylogeographic structure of the kingsnake using a range-wide data set sampled for the mitochondrial gene cytochrome b . We use coalescent simulation methods to test for the presence of structured lineage formation vs. fragmentation of a widespread ancestor. Finally, we use statistical techniques for creating and evaluating ecological niche models to test for conservatism of ecological niche preferences. Significant geographical structure is present in the kingsnake, for which coalescent tests indicate structured population division. Surprisingly, we find evidence for all three patterns of conservatism and divergence. This suggests that ecological niche preferences may be labile on recent phylogenetic timescales, and that lineage formation in widespread species can result from an interaction between inertial tendencies of niche conservatism and natural selection on populations in ecologically divergent habitats.  相似文献   

3.
Aim Theoretical work suggests that species’ ecological niches should remain relatively constant over long‐term ecological time periods, but empirical tests are few. We present longitudinal studies of 23 extant mammal species, modelling ecological niches and predicting geographical distributions reciprocally between the Last Glacial Maximum and present to test this evolutionary conservatism. Location This study covered distributional shifts in mammal species across the lower 48 states of the United States. Methods We used a machine‐learning tool for modelling species’ ecological niches, based on known occurrences and electronic maps summarizing ecological dimensions, to assess the ability of ecological niches as modelled in one time period to predict the geographical distribution of the species in another period, and vice versa. Results High intertemporal predictivity between niche models and species’ occurrences indicate that niche conservatism is widespread among the taxa studied, particularly when statistical power is considered as a reason for failure of reciprocal predictions. Niche projections to the present for 8 mammal taxa that became extinct at the end of the Pleistocene generally increased in area, and thus do not support the hypothesis of niche collapse as a major driving force in their extinction. Main conclusions Ecological niches represent long‐term stable constraints on the distributional potential of species; indeed, this study suggests that mammal species have tracked consistent climate profiles throughout the drastic climate change events that marked the end of the Pleistocene glaciations. Many current modelling efforts focusing on anticipating climate change effects on species’ potential geographical distributions will be bolstered by this result — in essence, the first longitudinal demonstration of niche conservatism.  相似文献   

4.
Spatial modelling of species distributions has become an important tool in the study of biological invasions. Here, we examine the utility of combining distribution and ecological niche modelling for retrieving information on invasion processes, based on species occurrence data from native and introduced ranges. Specifically, we discuss questions, concerning (1) the global potential to spread to other ranges, (2) the potential to spread within established invasions, (3) the detectability of niche differences across ranges, and (4) the ability to infer invasion history through data from the introduced range. We apply this approach to two congeneric pavement ants, Tetramorium sp.E (formerly T. caespitum (Linnaeus 1758)) and T. tsushimae Emery 1925, both introduced to North America. We identify (1) the potential of both species to inhabit ranges worldwide, and (2) the potential of T. sp.E and T. tsushimae, to spread to 23 additional US states and to five provinces of Canada, and to 24 additional US states and to one province of Canada, respectively. We confirm that (3) niche modelling can be an effective tool to detect niche shifts, identifying an increased width of T. sp.E and a decreased width of T. tsushimae following introduction, with potential changes in niche position for both species. We make feasible that (4) combined modelling could become an auxiliary tool to reconstruct invasion history, hypothesizing admixture following multiple introductions in North America for T. sp.E, and a single introduction to North America from central Japan, for T. tsushimae. Combined modelling represents a rapid means to formulate testable explanatory hypotheses on invasion patterns and helps approach a standard in predictive invasion research.  相似文献   

5.
Evolutionary processes such as adaptation, ecological filtering, and niche conservatism involve the interaction of organisms with their environment and are thus commonly studied along environmental gradients. Elevational gradients have become among the most studied environmental gradients to understand large-scale patterns of species richness and composition because they are highly replicated with different combinations of geographical, environmental and historical factors. We here review the literature on using elevational gradients to understand evolutionary processes in ferns. Some phylogenetic studies of individual fern clades have considered elevation in the analysis or interpretation and postulated that fern diversification is linked to the colonization of mountain habitats. Other studies that have linked elevational community composition and hence ecological filtering with phylogenetic community composition and morphological traits, usually only found limited phylogenetic signal. However, these studies are ultimately only correlational, and there are few actual tests of the evolutionary mechanisms leading to these patterns. We identify a number of challenges for improving our understanding of how evolutionary and ecological processes are linked to elevational richness patterns in ferns: i) limited information on traits and their ecological relevance, ii) uncertainties on the dispersal kernels of ferns and hence the delimitation of regional species pools from which local assemblages are recruited, iii) limited genomic data to identify candidate genes under selection and hence actually document adaptation and selection, and iv) conceptual challenges in developing clear and testable hypotheses to how specific evolutionary processes can be linked to patterns in community composition and species richness.  相似文献   

6.
Aim To understand the relative contributions of environmental factors, dispersal limitations and the presence of sperm donors in determining the distribution of the Amazon molly (Poecilia formosa), a sperm‐dependent unisexual fish species of hybrid origin. To explore niche similarities and/or differences between the hybrid and parental species. To evaluate whether large‐scale abiotic factors can explain a successful introduction of both P. formosa and Poecilia latipinna. Location South‐east United States, Mexico and Central America. Methods We used abiotic variables in ecological niche modelling (ENM) to identify regions with suitable conditions for the presence of the Amazon molly and its two parental species (P. latipinna and Poecilia mexicana). We also used a recently developed metric to calculate the degree of niche overlap between the hybrid and its parental species. Results ENM produced highly significant models [all area under the curve (AUC) > 0.99 for the three species]. Annual mean temperature and minimum temperature of the coldest month were the variables that best explained the distribution of the Amazon molly. With the exception of south Florida, few areas beyond the known distribution of the species were predicted to have suitable environmental conditions. The hybrid species niche overlaps partially with the parental species. However, given the available data, it is neither more similar nor more different than expected by chance. Main conclusions Two different processes are acting to limit the distribution of P. formosa. At the northern limit, although a sperm donor species is present further north, suitable environmental conditions are absent from nearby locations. At the southern limit, a sperm donor species is present and areas with good environmental conditions are present at nearby locations, suggesting that dispersal ability is the limiting factor. We found that the hybrid species overlaps in a similar way with both parental species while still having its own niche identity. This result may be explained by the fact that hybrid species inherit characteristics of two ecologically divergent species, which can result in intermediate or even transgressive phenotypes. These results support recent work on the role of hybridization in diversification.  相似文献   

7.
8.
Interspecific competition might drive the evolution of ecological niches and result in pairs of formerly competing species segregating along ecological gradients following a process of character displacement. This mechanism has been proposed to account for replacement of related species along gradients of elevation in many areas of the world, but the fundamental issue of whether competition is responsible for the origin of elevational replacements has not been tested. To test hypotheses about the role of interspecific competition in the origin of complementary elevational ranges, I combined molecular phylogenetics, phylogeography, and population genetic analyses on Buarremon torquatus and B. brunneinucha (Aves, Emberizidae), whose patterns of elevational distribution suggest character displacement or ecological release. The hypothesis that elevational distributions in these species changed in opposite directions as a result of competition is untenable because: (1) a historical expansion of the range of B. brunneinucha into areas occupied by B. torquatus was not accompanied by a shift in the elevational range of the former species; (2) when B. brunneinucha colonized the range of B. torquatus, lineages of the latter distributions had already diverged; and (3) historical trends in effective population size do not suggest populations with elevational ranges abutting those of putative competitors have declined as would be expected if competition caused range contractions. However, owing to uncertainty in coalescent estimates of historical population sizes, the hypothesis that some populations of B. torquatus have declined cannot be confidently rejected, which suggests asymmetric character displacement might have occurred. I suggest that the main role of competition in elevational zonation may be to act as a sorting mechanism that allows the coexistence along mountain slopes only of ecologically similar species that differ in elevational distributions prior to attaining sympatry. The contrasting biogeographic histories of B. brunneinucha and B. torquatus illustrate how present-day ecological interactions can have recent origins, and highlights important challenges for testing the hypothesis of character displacement in the absence of data on population history and robust reconstructions of the evolution of traits and geographic ranges.  相似文献   

9.
Aim The goal of this study was to determine the extent of suitable habitats across the basins and ranges of the Great Basin for 13 montane mammals in the present and during the Last Glacial Maximum (LGM). For all these mammal species, we test whether: (1) more suitable habitat was available in basin areas during the LGM; (2) suitable habitat shifted upwards in elevation between the LGM and the present; (3) more ranges have suitable habitat than are currently occupied; and (4) these species are currently restricted to suitable habitats at higher‐elevation range areas. We also examine whether and how much distributional response varies among these montane mammal species. Location The Great Basin of western North America. Methods We re‐examine the past and present distributions of 13 Great Basin montane mammals using ecological niche modelling techniques that utilize now widely available species occurrence data and new, fine‐scale past climatological GIS layers in the present and at the LGM. These methods provide an objective, repeatable means for visual comparison of past and present modelled distributions for species examined in previous biogeographical studies. Results Our results indicate greater areal and lower elevational suitable habitat in the LGM than at present for nearly all montane mammals, and that there is more suitable habitat at present than is currently occupied. Our results also show that lowland areas provide suitable dispersal routes between ranges for most of the montane mammals both at the LGM and at present. However, three of the 13 species have little to no predicted suitable habitat in the LGM near currently occupied ranges, in contrast to the pattern for the other 10. For these species, the model results support more recent long‐distance colonization. Main conclusions Our finding of suitable lowland dispersal routes in the present for most species supports and greatly extends similar findings from single‐species studies. Our results also provide a visually striking confirmation that changes in species distribution and colonization histories of Great Basin montane mammals vary in a fashion related to the tolerances and requirements of each of these species; this has previously been hypothesized but not rigorously tested for multiple montane mammals in the region.  相似文献   

10.
Local biological communities are made up of species, each of which has its own particular relationship with the environment. To the extent that these autecological niches limit species’ distributions, and by extension community composition, models of species’ ecological niches can predict species composition at particular sites, or at least provide a null hypothesis of potential species composition in the absence of effects of species interactions. We developed distributional predictions (ecological niche models) for 89 species occurring in dry tropical forest in the Balsas Basin of south‐western Mexico using an interpolation technique, and predicted the species likely to occur at 8 sites across the region. Onsite field inventory data were then used to test the community predictions, all of which were statistically significant. These results suggest that inventory efforts can be made more efficient by development beforehand of hypotheses that focus onsite collecting and inventory.  相似文献   

11.
Aim Species distribution models (SDMs) have been used to address a wide range of theoretical and applied questions in the terrestrial realm, but marine‐based applications remain relatively scarce. In this review, we consider how conceptual and practical issues associated with terrestrial SDMs apply to a range of marine organisms and highlight the challenges relevant to improving marine SDMs. Location We include studies from both marine and terrestrial systems that encompass many geographic locations around the globe. Methods We first performed a literature search and analysis of marine and terrestrial SDMs in ISI Web of Science to assess trends and applications. Using knowledge from terrestrial applications, we critically evaluate the application of SDMs in marine systems in the context of ecological factors (dispersal, species interactions, aggregation and ontogenetic shifts) and practical considerations (data quality, alternative modelling approaches and model validation) that facilitate or create difficulties for model application. Results The relative importance of ecological factors to be considered when applying SDMs varies among terrestrial and marine organisms. Correctly incorporating dispersal is frequently considered an important issue for terrestrial models, but because there is greater potential for dispersal in the ocean, it is often less of a concern in marine SDMs. By contrast, ontogenetic shifts and feeding have received little attention in terrestrial SDM applications, but these factors are important to many marine SDMs. Opportunities also exist for applying more advanced SDM approaches in the marine realm, including mechanistic ecophysiological models, where water balance and heat transfer equations are simpler for some marine organisms relative to their terrestrial counterparts. Main conclusions SDMs have generally been under‐utilized in the marine realm relative to terrestrial applications. Correlative SDM methods should be tested on a range of marine organisms, and we suggest further development of methods that address ontogenetic shifts and feeding interactions. We anticipate developments in, and cross‐fertilization between, coupled correlative and process‐based SDMs, mechanistic eco‐physiological SDMs, and spatial population dynamic models for climate change and species invasion applications in particular. Comparisons of the outputs of different model types will provide insight that is useful for improved spatial management of marine species.  相似文献   

12.
Aim The oceans harbour a great diversity of organisms whose distribution and ecological preferences are often poorly understood. Species distribution modelling (SDM) could improve our knowledge and inform marine ecosystem management and conservation. Although marine environmental data are available from various sources, there are currently no user‐friendly, high‐resolution global datasets designed for SDM applications. This study aims to fill this gap by assembling a comprehensive, uniform, high‐resolution and readily usable package of global environmental rasters. Location Global, marine. Methods We compiled global coverage data, e.g. satellite‐based and in situ measured data, representing various aspects of the marine environment relevant for species distributions. Rasters were assembled at a resolution of 5 arcmin (c. 9.2 km) and a uniform landmask was applied. The utility of the dataset was evaluated by maximum entropy SDM of the invasive seaweed Codium fragile ssp. fragile. Results We present Bio‐ORACLE (ocean rasters for analysis of climate and environment), a global dataset consisting of 23 geophysical, biotic and climate rasters. This user‐friendly data package for marine species distribution modelling is available for download at http://www.bio‐oracle.ugent.be . The high predictive power of the distribution model of C. fragile ssp. fragile clearly illustrates the potential of the data package for SDM of shallow‐water marine organisms. Main conclusions The availability of this global environmental data package has the potential to stimulate marine SDM. The high predictive success of the presence‐only model of a notorious invasive seaweed shows that the information contained in Bio‐ORACLE can be informative about marine distributions and permits building highly accurate species distribution models.  相似文献   

13.
Aim Various techniques model a species’ niche and potential distribution by comparing the environmental conditions of occurrence localities with those of the overall study region (via a background or pseudoabsence sample). Here, we examine how changes in the extent of the study region (ignored or under‐appreciated in most studies) affect models of two rodents, Nephelomys caracolus and Nephelomys meridensis. Location North‐central South America. Methods We used Maxent to model the species' potential distributions via two methods of defining the study region. In Method 1 (typical of most studies to date), we calibrated the model in a large study region that included the ranges of both species. In Method 2, we calibrated the model using a smaller study region surrounding the localities of the focal species, and then applied it to the larger region. Because the study region of Method 1 is likely to include areas of suitable conditions that are unoccupied because of dispersal limitations and/or biotic interactions, this approach is prone to overfitting to conditions found near the occupied localities. In contrast, Method 2 should avoid such problems but may require further assumptions (‘clamping’ in Maxent ) to make predictions for areas with environmental conditions beyond those found in the smaller study region. For each method, we calculated several measures of geographic interpredictivity between predictions for the species (cross‐species AUC, cross‐species omission rate, and proportional geographic overlap). Results Compared with Method 1, Method 2 revealed a larger predicted area for each species, less concentrated around known localities (especially for N. caracolus). It also led to higher cross‐species AUC values, lower cross‐species omission rates and higher proportions of geographic overlap. Clamping was minimal and occurred primarily in regions unlikely to be suitable. Main conclusions Method 2 led to more realistic predictions and higher estimates of niche conservatism. Conclusions reached by many studies depend on the selection of an appropriate study region. Although detailed information regarding dispersal limitations and/or biotic interactions will typically be difficult to obtain, consideration of coarse distributional patterns, topography and vegetational zones often should permit delimitation of a much more reasonable study region than the extremely large ones currently in common use.  相似文献   

14.
戴文渊  陈年来  李金霞  张芮 《生态学报》2021,41(4):1332-1340
作为生态环境至关重要的因素,水生态安全格局是生态安全格局的关键组成部分,科学评估水生态安全状况,进行生态系统管理及保护,对促进经济社会发展具有重要意义。选取甘肃地区17个流段为研究对象,基于SENCE (社会-经济-自然复合生态系统)概念构建涵盖经济发展、社会进步、自然资源、生态环境4方面33指标的初步水生态安全评价指标体系,基于改进生态位理论结合模糊系统分析对初步水生态安全评价指标体系进行优化,最终得到28指标构成的水生态安全评价优化指标体系,运用优化后指标体系对17流段2016-2018年间水生态安全状况模糊综合评价。结果表明:水生态安全状况良好(一级、二级)以上占比分别为35.3%、41.2%、35.3%,一般(三级)占比分别为57.8%、52.0%、46.1%,较差(四级)占比分别为23.5%、11.8%、11.8%,大致呈正态分布,且年际变化小,基本保持稳定。年平均降水量、河川基流量、地表水源供应量、生态环境用水量、节水灌溉面积等指标累计指标权重达47.75%,是影响水生态安全状况的主要影响因子。  相似文献   

15.
蒋啸  周旭  肖杨  罗雪  杨大方 《生态学报》2021,41(7):2571-2581
以湖泊生态系统健康维护为目标的生态管控分区成为水环境保护与治理的重要手段,有助于全面掌握流域生态状况,对流域生态经济可持续发展具有重要参考价值。以红枫湖流域为例,从水文水资源、物理结构、水质、生物、社会服务功能5个方面对湖泊生态系统健康进行评价。运用ArcGIS空间分析工具,以200 m×200 m格网为评价单元辨析流域生态敏感性和生态服务功能空间分异特征,进而运用SOFM聚类方法优选聚类方案,划定生态管控分区。结果表明:1)红枫湖湖泊生态系统健康评分为68.4分,属健康状态,物理结构是当前威胁红枫湖湖泊生态系统健康的主要因子;2)红枫湖流域生态敏感性及生态服务功能空间差异明显,生态环境脆弱,生态服务功能较低;3)红枫湖流域生态管控分区划为优先控制区、重点控制区、缓冲控制区及一般控制区,应实施差异化管理,重点任务是调结构、转方式,逐步修复生态系统。  相似文献   

16.
17.
The paper deals with the hypothesis that ecosystems have well-defined potentials of biodiversity. These potentials can be quantified as information entropy of the corresponding ecosystem type. The hypothesis is verified for the diversity of plant species.

A vegetation database of North-Central European forests containing more than 12000 relevés is analyzed computationally. The samples are classified into ecosystem types that are homogeneous with respect to vegetation patterns, ecological site factors, and, implicitly, with respect to ecosystem processes. Growing numbers of relevés are selected randomly from the representatives of different ecosystem types and investigated mathematically.

Shannon information (product of logarithmic species number and evenness) obeys a hyperbolic saturation equation approaching a finite value on infinite area. This asymptotic limit defines the ecological potential of species diversity. Within a given plant-geographical region, it is determined by ecological site factors like climate and soil controlling interrelations between plants. Competition relationships and hence potentials of phytodiversity are altered by management significantly. The curve of evenness versus area size is hump-shaped. Maximum evenness is proportional to the ecological potential of species diversity. The area size where evenness attains its maximum can be interpreted as the minimum area of the respective forest type. The ecological potentials of plant species diversity modelled from information entropies correspond to vegetation patterns consisting of a limited number of plant species. These vegetation patterns are closely related to ecosystem processes like nutrient cycling, plant nutrition, evapotranspiration, microbial processes, or net-primary production. Revealing the relationships between vegetation patterns and ecosystem processes allows scaling functional information from local measurement scales up to regional scales.

It is suggested to explore genetic, proteomic, and species data in order to derive comprehensive ecological potentials of biodiversity on various levels from population to landscape. The expected results could improve the understanding of the relationship between biodiversity and ecosystem functioning as well as the sustainability of ecosystem management.  相似文献   


18.
农田生态补偿作为一种控制化肥用量与面源污染的公共政策工具,其补偿标准将决定政策内化外部效应的实际效果。以南京市溧水区水稻种植户为对象,综合运用成本收益法、能值分析法和双边界二分式CVM法,测定基于政府和农户双重视角下的稻田化肥减施生态补偿标准。研究结果表明:化肥污染环境成本量化视角下南京市水稻种植过程中的折纯化肥投入参考值为268.75 kg hm~(-2)a~(-1),相比2017年南京市的实际化肥用量312.48 kg hm~(-2)a~(-1)仍有约14%的下降空间;绝大多数种植户愿意在接受平均补偿标准为882.49元hm~(-2)a~(-1)的前提之下减少化肥投入至参考用量;受教育程度越高、家中务农人数越多、化肥投入成本越高的稻农更倾向于接受生态补偿,而种植面积较大的农户以及年长男性种植户对减施化肥持更谨慎的态度。研究结果为南京市农业面源污染防治和稻田生态补偿标准制定提供了一定的理论支撑,在实际补偿发放过程中,单一的补偿标准无法保障公平公正,需建立与作物种植类型、化肥减施成效相挂钩的分级生态补偿制度,从而激励农户尽可能减少化肥投入。  相似文献   

19.
闵庆文  何永涛  李文华  李贵才 《生态学报》2004,24(10):2130-2135
从农业气象学原理出发 ,森林植被的生态需水可以理解为林地的蒸散耗水量。根据土壤水分有效性的划分 ,林木暂时凋萎含水量和生长阻滞含水量分别是能保证林木基本生存和正常生长时土壤含水量的下限 ,据此可以作为林地最小生态需水定额和适宜生态需水定额计算的依据 ,其数值通过计算林地的潜在蒸散并利用土壤水分修正系数和林木系数进行订正获得。根据遥感图像资料 ,在 GIS支持下 ,计算了泾河流域现有林地生长季的最小生态需水量和适宜生态需水量 ,分别为 2 0 396 0× 10 4 m3和340 330× 10 4 m3。  相似文献   

20.
李潇  吴克宁  刘亚男  冯喆  谢家麟 《生态学报》2019,39(23):8806-8816
开展山水林田湖草生态保护修复是生态文明建设的重要内容,将生态系统服务评价成果与山水林田湖草生态保护修复工程相结合,以国家第三批山水林田湖草生态保护修复试点-河南省南太行地区鹤山区为例,探究生态系统服务评价成果在区域山水林田湖草生态保护修复中的应用。结果表明,近年来鹤山区生态系统服务价值整体呈下降趋势且生态环境破坏严重。其中,2014-2017年鹤山区各土地类型二级服务ESV减少了303.95万元。研究期内,水资源供给、气体调节功能、气候调节、净化环境、水文调节、土壤保持、生物多样性和美学景观等8项生态服务价值都出现不同程度的下降;在鹤山区生态保护修复工作中需要重点关注生态系统的水文调节、净化环境、土壤保持和生物多样性等服务功能,相应的生态保护修复工程应集中在河道生态修复与湿地保护、矿山生态环境修复与土地整治、森林及生物多样性保护修复;鹤山区山水林田湖草生态保护修复工程能够提升区域生态服务价值。其中,工程实施后的生态系统服务价值总量预计能达到36407.95万元,比2017年增加7741.96万元,增长率为27%且各项生态服务价值均有提升。研究结果对鹤山区山水林田湖草生态保护修复工程的实施有一定的指导性作用。  相似文献   

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