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1.
Vignieri SN 《Molecular ecology》2005,14(7):1925-1937
In species affiliated with heterogeneous habitat, we expect gene flow to be restricted due to constraints placed on individual movement by habitat boundaries. This is likely to impact both individual dispersal and connectivity between populations. In this study, a GIS-based landscape genetics approach was used, in combination with fine-scale spatial autocorrelation analysis and the estimation of recent intersubpopulation migration rates, to infer patterns of dispersal and migration in the riparian-affiliated Pacific jumping mouse (Zapus trinotatus). A total of 228 individuals were sampled from nine subpopulations across a system of three rivers and genotyped at eight microsatellite loci. Significant spatial autocorrelation among individuals revealed a pattern of fine-scale spatial genetic structure indicative of limited dispersal. Geographical distances between pairwise subpopulations were defined following four criteria: (i) Euclidean distance, and three landscape-specific distances, (ii) river distance (distance travelled along the river only), (iii) overland distance (similar to Euclidean, but includes elevation), and (iv) habitat-path distance (a least-cost path distance that models movement along habitat pathways). Pairwise Mantel tests were used to test for a correlation between genetic distance and each of the geographical distances. Significant correlations were found between genetic distance and both the overland and habitat-path distances; however, the correlation with habitat-path distance was stronger. Lastly, estimates of recent migration rates revealed that migration occurs not only within drainages but also across large topographic barriers. These results suggest that patterns of dispersal and migration in Pacific jumping mice are largely determined by habitat connectivity. 相似文献
2.
1. Mazerolle et al. (2006) concluded that some aquatic invertebrate species, including bog‐associated species, readily colonise man‐made bog pools. In contrast, in Dutch bog remnants Van Duinen et al. (2003) found that a considerable number of bog‐associated species do not colonise newly created bog pools. 2. The conclusion of Mazerolle et al. (2006) is based on vagile aquatic invertebrates. Here, we question whether their conclusion can be extended to more sedentary species, which were not captured in the Canadian study, but made up an important part of the invertebrate assemblage in the Dutch study. This discrepancy could be caused by sampling artefacts, low colonisation rates of these species or an incomplete restoration of site conditions. 3. In Canada, chances of recolonisation may be higher than in the Netherlands, as natural and near‐natural bogs are more extensive. In the Netherlands, with low chances of recolonisation, persistence of species may be more important. To disentangle the relative importance of persistence and recolonisation, evaluations of the success of restoration projects need to cover the entire invertebrate assemblage, including both vagile and more sedentary species. 相似文献
3.
Abstract
Integration of habitat heterogeneity into spatially realistic metapopulation approaches reveals the potential for key cross-scale
interactions. Broad-scale environmental gradients and land-use practices can create autocorrelation of habitat quality of
suitable patches at intermediate spatial scales. Patch occupancy then depends not only on habitat quality at the patch scale
but also on feedbacks from surrounding neighborhoods of autocorrelated patches. Metapopulation dynamics emerge from how demographic
and dispersal processes interact with relevant habitat heterogeneity. We provide an empirical example from a metapopulation
of round-tailed muskrats (Neofiber
alleni) in which habitat quality of suitable patches was spatially autocorrelated most strongly within 1,000 m, which was within
the expected dispersal range of the species. After controlling for factors typically considered in metapopulation studies—patch
size, local patch quality, patch connectivity—we use a cross-variogram analysis to demonstrate that patch occupancy by muskrats
was correlated with habitat quality across scales ≤1,171 m. We also discuss general consequences of spatial heterogeneity
of habitat quality for metapopulations related to potential cross-scale interactions. We focus on spatially correlated extinctions
and metapopulation persistence, hierarchical scaling of source–sink dynamics, and dispersal decisions by individuals in relation
to information constraints. 相似文献
4.
John E. Banks Amanda N. Laubmeier H. Thomas Banks 《Agricultural and Forest Entomology》2020,22(1):30-40
- Diversifying agroecosystems by establishing or retaining natural vegetation in and around crop areas has long been recognized as a potentially effective means of bolstering pest control as a result of attracting more numerous and diverse natural enemies, although outcomes are inconsistent across species.
- Little is known about the underlying mechanisms driving such differences in species responses, creating challenges for determining how best to manage landscapes for maximizing environmental services such as biological control.
- The present study addresses gaps in our understanding of the link between noncrop vegetation in field margins and pest suppression by using a system of partial differential equations to model population‐level predator–prey interactions, as well as spatial processes, aiming to capture the dynamics of crop plants, herbivores and two generalist predators.
- We focus on differences in how two predators (a carabid and a ladybird beetle) colonize crop fields where they forage for prey, examining differences in how they move into the fields from adjacent vegetation as a potential driver of differences in overall pest suppression.
- The results obtained demonstrate that predator colonization behaviour and spatial scale are important factors with respect to determining the effectiveness of biological control.
5.
Clay Trauernicht Brett P. Murphy Natalia Tangalin David M. J. S. Bowman 《Ecology and evolution》2013,3(2):286-297
We use the fire ecology and biogeographical patterns of Callitris intratropica, a fire‐sensitive conifer, and the Asian water buffalo (Bubalus bubalis), an introduced mega‐herbivore, to examine the hypothesis that the continuation of Aboriginal burning and cultural integration of buffalo contribute to greater savanna heterogeneity and diversity in central Arnhem Land (CAL) than Kakadu National Park (KNP). The ‘Stone Country’ of the Arnhem Plateau, extending from KNP to CAL, is a globally renowned social–ecological system, managed for millennia by Bininj‐Kunwok Aboriginal clans. Regional species declines have been attributed to the cessation of patchy burning by Aborigines. Whereas the KNP Stone Country is a modern wilderness, managed through prescribed burning and buffalo eradication, CAL remains a stronghold for Aboriginal management where buffalo have been culturally integrated. We surveyed the plant community and the presence of buffalo tracks among intact and fire‐damaged C. intratropica groves and the savanna matrix in KNP and CAL. Aerial surveys of C. intratropica grove condition were used to examine the composition of savanna vegetation across the Stone Country. The plant community in intact C. intratropica groves had higher stem counts of shrubs and small trees and higher proportions of fire‐sensitive plant species than degraded groves and the savanna matrix. A higher proportion of intact C. intratropica groves in CAL therefore indicated greater gamma diversity and habitat heterogeneity than the KNP Stone Country. Interactions among buffalo, fire, and C. intratropica suggested that buffalo also contributed to these patterns. Our results suggest linkages between ecological and cultural integrity at broad spatial scales across a complex landscape. Buffalo may provide a tool for mitigating destructive fires; however, their interactions require further study. Sustainability in the Stone Country depends upon adaptive management that rehabilitates the coupling of indigenous culture, disturbance, and natural resources. 相似文献
6.
The color of noise and the evolution of dispersal 总被引：2，自引：0，他引：2
Justin M. J. Travis 《Ecological Research》2001,16(1):157-163
The process of dispersal is vital for the long-term persistence of all species and hence is a ubiquitous characteristic of living organisms. A present challenge is to increase our understanding of the factors that govern the dispersal rate of individuals. Here I extend previous work by incorporating both spatial and temporal heterogeneity in terms of patch quality into a spatially explicit lattice model. The spatial heterogeneity is modeled as a two-dimensional fractal landscape, while temporal heterogeneity is included by using one-dimensional noise. It was found that the color of both the spatial and temporal variability influences the rate of dispersal selected as reddening of the temporal noise leads to a reduction in dispersal, while reddening of spatial variability results in an increase in the dispersal rate. These results demonstrate that the color of environmental noise should be considered in future studies looking at the evolution of life history characteristics. 相似文献
7.
《Evolutionary Applications》2018,11(8):1305-1321
Functional connectivity, quantified using landscape genetics, can inform conservation through the identification of factors linking genetic structure to landscape mechanisms. We used breeding habitat metrics, landscape attributes, and indices of grouse abundance, to compare fit between structural connectivity and genetic differentiation within five long‐established Sage‐Grouse Management Zones (MZ) I‐V using microsatellite genotypes from 6,844 greater sage‐grouse (Centrocercus urophasianus) collected across their 10.7 million‐km2 range. We estimated structural connectivity using a circuit theory‐based approach where we built resistance surfaces using thresholds dividing the landscape into “habitat” and “nonhabitat” and nodes were clusters of sage‐grouse leks (where feather samples were collected using noninvasive techniques). As hypothesized, MZ‐specific habitat metrics were the best predictors of differentiation. To our surprise, inclusion of grouse abundance‐corrected indices did not greatly improve model fit in most MZs. Functional connectivity of breeding habitat was reduced when probability of lek occurrence dropped below 0.25 (MZs I, IV) and 0.5 (II), thresholds lower than those previously identified as required for the formation of breeding leks, which suggests that individuals are willing to travel through undesirable habitat. The individual MZ landscape results suggested terrain roughness and steepness shaped functional connectivity across all MZs. Across respective MZs, sagebrush availability (<10%–30%; II, IV, V), tree canopy cover (>10%; I, II, IV), and cultivation (>25%; I, II, IV, V) each reduced movement beyond their respective thresholds. Model validations confirmed variation in predictive ability across MZs with top resistance surfaces better predicting gene flow than geographic distance alone, especially in cases of low and high differentiation among lek groups. The resultant resistance maps we produced spatially depict the strength and redundancy of range‐wide gene flow and can help direct conservation actions to maintain and restore functional connectivity for sage‐grouse. 相似文献
8.
Jiajia Liu Deyan Wu Xiaoyu Peng Shurong Zhou Corey J. A. Bradshaw 《Journal of Plant Ecology》2013,6(4):277
Aims We aim to quantify the relative importance of various endogenous and exogenous processes influencing the spatial distribution of the individuals of plant species at different temporal and spatial scales in a species-rich and high-cover meadow in the eastern Tibetan Plateau.Methods We calculated Green's index of dispersion to infer the spatial distribution patterns of 73 herbaceous species at two scales (0.25 and 1.0 m 2). We constructed a series of generalized linear models to test the hypotheses that different species traits such as mean plant stem density, per capita dry biomass, maximum plant height and mean seed mass contribute to their spatial distribution. We used the first principal component of soil C, N and P to explain abundance variation across quadrats and sub-plots.Important findings The individuals of the species studied were highly spatially aggregated. At both spatial scales, biomass and stem density explained the most variation in aggregation, but there was no evidence for an effect of mean seed mass on aggregation intensity. The effects of soil carbon, nitrogen and phosphorus at different depths affected plant abundance mostly at the broader spatial scale. Our results demonstrate that self-thinning and habitat heterogeneity all contribute to determine the spatial aggregation patterns of plant individuals in alpine meadow vegetation in the eastern Tibetan Plateau. 相似文献
9.
生物多样性的地理格局及其形成机制是宏生态学与生物地理学的研究热点。大量研究表明,景观尺度上的生境破碎化对物种多样性的分布格局具有重要作用,但目前尚不清楚这种作用是否足以在宏生态尺度上对生物多样性地理格局产生显著影响。利用中国大陆鸟类和哺乳动物的物种分布数据,在100 km×100 km网格的基础上生成了这两个类群生物的物种丰富度地理格局,进一步利用普通最小二乘法模型和空间自回归模型研究了物种丰富度与气候、生境异质性、景观破碎化的相关关系。结果表明,景观破碎化因子与鸟类和哺乳动物的物种丰富度都具有显著的关联关系,其方差贡献率可达约30%—50%(非空间模型)和60%—80%(空间模型),略低于或接近于气候和生境异质性因子。方差分解结果显示,景观破碎化因子与气候和生境异质性因子的方差贡献率的重叠部分达20%—40%。相对鸟类而言,景观破碎化对哺乳动物物种丰富度的地理格局具有更高的解释率。 相似文献
10.
Many efforts have been undertaken to reduce the impairment of stream ecosystems by wastewaters and other pollution, leading to a remarkable improvement of the water quality in most parts of Central Europe. Actually, the most severe disturbance to stream systems in Central Europe is the structural degradation of stream morphology. Restoration practices increasing the structural heterogeneity of formerly degraded stream sections are necessary to create new habitats at different scales that could provide habitat for a diverse invertebrate community. Increasing biodiversity of aquatic invertebrates strengthens the ecological integrity of streams and is therefore a desirable goal in stream restoration. Nevertheless, recent studies focusing on the effect of structural restoration of stream sections often displayed results that did not really met the preset goal of increasing invertebrate diversity. This might be due to sometimes severe disturbance caused by the restoration practice itself, impairing the established invertebrate community in the restored stream section. Additionally, the potential for immigration of new species into the restored stream section is often limited. Therefore, several important prerequisites must be accounted for in the planning of restoration practices to improve structurally degraded stream sections, when the goal of restoration is increasing invertebrate diversity. 相似文献
11.
森林木本植物的空间格局有助于揭示群落结构的形成机制与潜在的生态学过程,且对林分经营具有一定指导意义。在0—50 m尺度范围内综合分析了辽东山区4 hm2温带次生林样地多度10的树种空间格局。研究发现:(1)在完全随机零模型下,大部分树种呈现聚集格局,聚集格局树种的比例随尺度增加而降低;在32 m的较大尺度下,随尺度增加,随机和规则格局成为树种分布的主要形式;(2)在异质性泊松过程零模型下,55.9%的树种呈现随机格局,其余大部分树种在10 m的尺度下呈现聚集格局,且随尺度增加,规则格局成为主要形式;(3)在完全随机零模型下,树种属性(林层、径级和多度)显著地影响种群聚集度,而在异质性泊松过程零模型下,树种属性对种群聚集度不存在显著影响。综上,生境异质性、扩散限制和树种属性部分解释了辽东山区次生林木本植物空间分布格局,相对而言,生境异质性的效应更为突出。研究结果有助于揭示次生林群落生物多样性的维持机制。 相似文献
12.
森林群落内强烈生境异质性可能会驱动不同树种间形成空间隔离,从而塑造出与局域复杂生境相适应的群落树种空间结构。该文以广西喀斯特季节性雨林中具有不同生境异质性强烈程度的3个典型森林群落1 hm2样地为研究对象,通过分析主要树种的种内空间分布格局和种间关联格局来量化群落树种空间结构,检测其对喀斯特局域生境隔离作用的响应规律。结果表明：（1）3个森林群落树种的空间分布格局整体上以中小尺度聚集分布为主,在较小尺度（0～13 m）上聚集分布比例为85%,在中尺度（13～30 m）上逐步降低至60%,在较大尺度（>30 m）上降低至20%以下;随着生境异质性强烈程度的增加,群落内中小尺度种内聚集分布的比例逐步增加,平均值分别为63.1%、89.5%、94.4%。（2）3个森林群落树种的种间关联格局整体上以空间隔离和部分重叠为主;在小尺度（0～3 m）上二者共占50%,在中小尺度（3～20 m）上占70%,在较大尺度（>20 m）上逐步降低至40%;随着生境异质性强烈程度增加,群落中小尺度种间空间隔离和部分重叠的比例逐步增加,平均值分别为60.4%、70.2%、83.7%。综上结果表明,强烈的局域喀斯特生境异质性会增加群落树种的种内聚集分布强度,提高群落不同树种之间产生空间隔离的概率,说明局域复杂生境的隔离作用是塑造喀斯特森林群落树种空间结构的重要因素。该研究强调,在喀斯特石漠化区域进行植被生态恢复时,需充分评估不同地段生境条件,并参考相应原生境森林群落来配置树种及其空间组合。 相似文献
13.
Food chains culminating with temperate insectivorous passerines are well described, yet whether trophic webs can be site‐specific remains a largely unexplored question. In the case of site‐ or habitat‐specificity of food webs, stable isotope signatures of bird feathers may enable assignment of unmarked individuals to a site or a habitat of origin. We address this question in landscapes that include contrasting forest habitat patches with either deciduous Downy Oak Quercus humilis or evergreen Holm Oak Quercus ilex as dominant tree species. First, we examine the spatial variation across habitats and sites in the stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) along the oak leaf–Tortrix moth Tortrix viridana caterpillar–Blue Tit Cyanistes caeruleus food chain. Secondly, we assess whether the isotopic signatures allow for correct assignment of individual birds to their site or habitat of origin. At the scale of the landscape, stable isotope values enabled identification of the different components of the Blue Tit food chain: from oak leaves to Blue Tit nestlings and yearling birds. However, isotopic signatures were site‐specific (i.e. geographical) more than habitat‐specific (i.e. deciduous vs. evergreen oaks). Discriminant analyses correctly assigned 85% of nestlings and 83% of resident yearling birds, indicating a pronounced effect of site on Blue Tit feather isotopic signatures. We thereby demonstrate that isotopes reflect a stronger association of locally born birds to the local features of their habitat than that of un‐ringed yearling birds, whose plumage may have grown while in a wider geographical area. This study provides evidence of site‐specific isotopic signatures from oak leaves to Blue Tit feathers at a fine spatial scale. 相似文献
14.
Rieks D. van Klinken Justine V. Murray Javier N. Garcia Anthony R. Clarke 《The Annals of applied biology》2019,175(3):350-362
Control of mobile pests frequently requires area‐wide management (AWM) that spans commercial and non‐commercial habitats. Spatial modelling of habitat suitability can guide investment and implementation of AWM, but current approaches rarely capture population drivers, including local foraging, at an appropriate spatial resolution. To support the development of AWM for the fruit fly pest, Bactrocera tryoni (Tephritidae), we developed a habitat suitability model for the three premier fruit‐growing regions in south‐eastern Australia (~34,780 km2). Expert elicitation and published literature was used to develop a Bayesian network to model the drivers of B. tryoni habitat suitability, as determined by the ability of populations to persist and increase. The effect of uncertainty was tested through sensitivity analysis. The model was then linked with spatially explicit data (at 10 m resolution) to generate risk maps, using moving windows to capture local foraging movement. Habitat suitability was most strongly influenced by host availability within a distance of 200 m. Climate stress, and soil moisture for pupation, was also limiting. Experts were uncertain regarding the relative importance of drivers of host availability (host preference, host density, fruit seasonality), but this did not greatly affect model outputs. Independent trapping data supported model predictions, but their value was limited as traps were placed almost exclusively in optimal or suitable habitat. Amenability to AWM, when assessed as the ratio of suitable or optimal habitat that was under non‐horticultural versus horticultural land‐uses, differed by region (0.15–1.17). However, risk‐mapping did identify where ratios were locally most favourable (lowest). Also, predominantly local dispersal by B. tryoni suggests AWM for pest suppression could be applied at a landscape‐scale. Results show that a relatively simple model could capture the multi‐scale drivers of population dynamics and the complexity of landscapes sufficiently to guide AWM of a mobile pest. 相似文献
15.
1. The Grampians National Park in Victoria is a ‘hot spot’ for freshwater crayfish diversity, with seven species from six genera occurring in sympatry. Few studies have examined how multiple species of freshwater crayfish co‐exist across landscapes consisting of a mosaic of perennial and seasonal habitats. Despite their endemicity and likely key role in freshwaters, the ecology and biology of these crayfish remains unknown. 2. This study determined the distribution and habitat use of five crayfish species (Euastacus bispinosus, Cherax destructor, Geocharax falcata, Gramastacus insolitus and Engaeus lyelli). Seasonal sampling surveys ascertained whether crayfish distribution was related to habitat type, environmental or physicochemical variables, catchment or season. 3. Distribution was directly related to habitat type and the environmental and physicochemical variables that characterised habitats. Engaeus lyelli, G. falcata and G. insolitus occurred predominantly in floodplain wetlands and flooded vegetation habitats, E. bispinosus occurred only in flowing soft‐sediment channels and C. destructor was found in all catchments and habitat types studied. Gramastacus insolitus co‐occurred with G. falcata at all sites except two, so no distinct habitat separations were apparent for these two species. 4. A high percentage cover of boulders was the best indicator of crayfish absence, and discriminated between habitat types and crayfish species: it was probably a surrogate for a larger range of environmental and physicochemical variables. Catchment and season did not affect crayfish distribution. 5. These crayfish species varied in their degree of habitat specialisation from strongly generalist (C. destructor) to occupying only a specific habitat type (E. bispinosus). Some species appeared specialised for seasonal wetlands (G. insolitus and G. falcata). Overlap in site occupancy also varied: G. insolitus and G. falcata distributions were strongly associated, whereas C. destructor appeared to occur opportunistically across habitats, both alone and co‐occurring with all the other species. 6. Management strategies to conserve multiple species of crayfish co‐existing within landscapes will need to incorporate a range of perennial and seasonal habitat types to ensure sufficient space is available for species to maintain different occupancy patterns. Given that water resources are under increasing pressure and are strongly regulated within the Grampians National Park, this may present a conservation challenge to water managers in this location. 相似文献
16.
17.
该研究以湖北木林子保护区优势种翅柃(Eurya alata)为研究对象,编制静态生命表,绘制存活曲线、死亡率和消失率曲线;采用成对相关函数分析各龄级的空间分布特征,双变量成对相关函数分析不同生活史阶段间的空间关系,为阐明木林子保护区常绿落叶阔叶混交林不同构建规律在物种多样性维持机制中的作用提供理论参考。结果显示:(1)翅柃属增长型种群,存活曲线趋于Deevey-Ⅱ型,死亡率和消失率曲线呈单峰型。(2)翅柃Ⅰ～Ⅴ龄级呈现聚集分布且随径级增加而减弱,Ⅵ、Ⅶ龄级在较大尺度上随机分布。(3)在完全随机零模型下,各生活史阶段均呈空间正关联;在先决条件零模型下,成年树与幼树、小树小尺度上呈无关联和负关联,其余生活史阶段间呈正关联,较大尺度上无关联。研究表明,翅柃种群幼树个体丰富,更新状态良好,在自然演替过程中,生境过滤、扩散限制和密度制约均可能驱动种群的构建过程。 相似文献
18.
Understanding factors that ameliorate the impact of habitat loss is a major focus of conservation research. One key factor influencing species persistence and evolution is the ability to disperse across increasingly patchy landscapes. Here we ask whether interpatch distance (a proxy for habitat loss) and dispersal strategy can interact to form thresholds where connectivity breaks down. We assayed dispersal across a range of interpatch distances in fruit flies carrying allelic variants of a gene known to underlie differences in dispersal strategy. Dispersal‐limited flies experienced a distinct negative threshold in connectivity at greater interpatch distances, and this was not observed in more dispersive flies. Consequently, this differential response of dispersal‐limited and more dispersive flies to decreasing connectivity suggests that habitat loss could have important implications on the evolution and maintenance of genetic variation underlying dispersal strategy. 相似文献
19.
Y. R. Delettre 《Aquatic Ecology》1992,26(2-4):269-271
Terrestrial Chironomidae were studied for one year in four closely related habitats (pondbanks, woodland, grassland, heathland). Community structure and emergence phenology are analysed and compared with the aerial flow composition and timing. The contribution of local emergence to aerial flow is estimated using Principal Component Analysis with Instrumental Variables (PCAIV). Results are discussed, taking in account larval capabilities, adults behaviour and landscape heterogeneity. 相似文献
20.
Abstract The reduction and fragmentation of forest habitats is expected to have profound effects on plant species diversity as a consequence of the decreased area and increased isolation of the remnant patches. To stop the ongoing process of forest fragmentation, much attention has been given recently to the restoration of forest habitat. The present study investigates restoration possibilities of recently established patches with respect to their geographical isolation. Because seed dispersal events over 100 m are considered to be of long distance, a threshold value of 100 m between recent and old woodland was chosen to define isolation. Total species richness, individual patch species richness, frequency distributions in species occurrences, and patch occupancy patterns of individual species were significantly different among isolated and nonisolated stands. In the short term no high species richness is to be expected in isolated stands. Establishing new forests adjacent to existing woodland ensures higher survival probabilities of existing populations. In the long term, however, the importance of long‐distance seed dispersal should not be underestimated because most species showed occasional long‐distance seed dispersal. A clear distinction should be made between populations colonizing adjacent patches and patches isolated from old woodland. The colonization of isolated stands may have important effects on the dynamics and diversity of forest networks, and more attention should be directed toward the genetic traits and viability of founding populations in isolated stands. 相似文献