景观生态学与退化生态系统恢复

退化生态系统的恢复是一项艰巨任务,它需要考虑到所要恢复的退化生态系统的结构,多样性和其动态的整体性和长期性。现在对于退化生态系统恢复研究已经要使生态学家们关注受损生态系统的理论和实际问题。退化生态系统恢复所面临的挑战是理解和利用生态演替理论来完成并加速恢复进程。恢复的主要目标是建立一个自维持的,由不同的群落或生态系统组成的能够满足不同需要如生物保护和粮食生产需要的景观。景观生态学关注于大的空间尺度的生态学问题。景观生态学研究方法可以为退化生态系统恢复实践提供指导。在解决退化生态系统的恢复问题时,景观生态学的方法在理论和实践上是有效的。景观生态学中的核心概念和其一般原理斑块形状、生态系统间相互作用、镶嵌系列等都同退化生态系统的恢复有着密切的关系。如恢复地点的选择和适当的恢复要素的空间配置。在评价退化生态系统的恢复是否取得成功,利用景观生态学也具有重要的意义。景观生态学理论如景观格局与景观异质性理论,干扰理论和尺度理论都能够指导退化生态系统的恢复实践。同样地,退化生态系统的恢复可以为景观生态学的研究提供非常恰当的实验场。寓景观生态学思想于退化生态系统恢复过程是一种新的有效途径。     

Characterizing the post‐recolonization of Antechinus flavipes and its genetic implications in a production forest landscape

Production landscapes, where activities such as timber harvesting, grazing, and resource extraction take place, have considerably reduced the extent of natural habitats. The ecological restoration of these landscapes is, in many cases, the best remaining option to protect biodiversity. However, it is unclear whether restoration designed to avert biodiversity loss in restored landscapes can also maintain genetic diversity in recolonizing faunal populations. We employed core concepts in the field of population genetics to address questions of genetic diversity and gene flow in recolonizing faunal populations, using a small and vagile marsupial (Antechinus flavipes) inhabiting a mined landscape under restoration. We did not detect a disruption of gene flow that led to genetic substructuring, suggesting adequate levels of gene flow across the landscape. Parameters of neutral genetic diversity were high in groups of individuals sampled in both restored and unmined sites. Our results are encouraging as they indicate that ecological restoration has the potential to not just increase available habitat, but also to maintain genetic diversity. However, there is evidence that past anthropogenic disturbances affected the genetics of the population at the regional level. Although restoration at the local level may seem to be successful, it is necessary to manage populations at larger spatial scales than where restoration is conducted, and over long temporal scales, if genetic diversity is to be maintained in restored landscapes. The field of population genetics is an underused tool in ecological restoration yet can provide important insights into how well restoration achieves its goals.     

A Framework to Optimize Biodiversity Restoration Efforts Based on Habitat Amount and Landscape Connectivity

The effectiveness of ecological restoration actions toward biodiversity conservation depends on both local and landscape constraints. Extensive information on local constraints is already available, but few studies consider the landscape context when planning restoration actions. We propose a multiscale framework based on the landscape attributes of habitat amount and connectivity to infer landscape resilience and to set priority areas for restoration. Landscapes with intermediate habitat amount and where connectivity remains sufficiently high to favor recolonization were considered to be intermediately resilient, with high possibilities of restoration effectiveness and thus were designated as priority areas for restoration actions. The proposed method consists of three steps: (1) quantifying habitat amount and connectivity; (2) using landscape ecology theory to identify intermediate resilience landscapes based on habitat amount, percolation theory, and landscape connectivity; and (3) ranking landscapes according to their importance as corridors or bottlenecks for biological flows on a broader scale, based on a graph theory approach. We present a case study for the Brazilian Atlantic Forest (approximately 150 million hectares) in order to demonstrate the proposed method. For the Atlantic Forest, landscapes that present high restoration effectiveness represent only 10% of the region, but contain approximately 15 million hectares that could be targeted for restoration actions (an area similar to today's remaining forest extent). The proposed method represents a practical way to both plan restoration actions and optimize biodiversity conservation efforts by focusing on landscapes that would result in greater conservation benefits .     

Habitat Loss,Fragmentation, and Restoration

The loss and fragmentation of habitat is a major threat to the continued survival of many species. We argue that, by including spatial processes in restoration management plans, the effects of habitat loss and fragmentation can be offset. Yet few management plans take into account spatial effects of habitat conservation/restoration despite the importance of spatial dynamics in species conservation and recovery plans. Tilman et al. (1997) found a “restoration lag” in simulations of species restoration when randomly selecting habitat for restoration. Other studies have suggested that the placement of restored habitat can overcome effects of habitat loss and fragmentation. Here we report the findings of simulations that examine different regional management strategies, focusing on habitat selection. We find that nonrandom restoration practices such as restoring only habitat that is adjacent to those occupied by the target species can dramatically reduce or negate any restoration lag. In fact, we find that the increase in patch occupancy of the landscape can be greater than two-fold in the adjacent versus the random scenarios after only two restoration events, and this increase can be as great as six-fold during the early restoration phase. Many restoration efforts have limitations on both funds and available sites for restoration, necessitating high potential success on any restoration efforts. The incorporation of spatial analyses in restoration management may drastically improve a species' chance of recovery. Therefore, general principles that incorporate spatial processes and sensible management are needed to guide specific restoration efforts.     

The restoration of biodiversity: where has research been and where does it need to go?

The practice of ecological restoration is a primary option for increasing levels of biodiversity by modifying human-altered ecosystems. The scientific discipline of restoration ecology provides conceptual guidance and tests of restoration strategies, with the ultimate goal of predictive landscape restoration. I construct a conceptual model for restoration of biodiversity, based on site-level (e.g., biotic and abiotic) conditions, landscape (e.g, interpatch connectivity and patch geometry), and historical factors (e.g., species arrival order and land-use legacies). I then ask how well restoration ecology has addressed the various components of this model. During the past decade, restoration research has focused largely on how the restoration of site-level factors promotes species diversity-primarily of plants. Relatively little attention has been paid to how landscape or historical factors interplay with restoration, how restoration influences functional and genetic components of biodiversity, or how a suite of less-studied taxa might be restored. I suggest that the high level of variation seen in restoration outcomes might be explained, at least in part, by the contingencies placed on site-level restoration by landscape and historical factors and then present a number of avenues for future research to address these often ignored linkages in the biodiversity restoration model. Such work will require carefully conducted restoration experiments set across multiple sites and many years. It is my hope that by considering how space and time influence restoration, we might move restoration ecology in a direction of stronger prediction, conducted across landscapes, thus providing feasible restoration strategies that work at scales over which biodiversity conservation occurs.     

From Biodiversity to Ecodiversity: A Landscape-Ecology Approach to Conservation and Restoration

An environmental revolution is urgently needed that will lead to a post-industrial symbiosis between man and nature. This can be realized only if the present unrestrained biological impoverishment and neotechnological landscape degradation are replaced by the creation of healthy and attractive landscapes. Restorationists can fulfill a vital role in this process. They must broaden their scales from biodiversity restoration in small, protected nature islands to the large-scale restoration of natural and cultural landscapes. To achieve this they must restore not only the patterns of vegetation but also the processes that create these patterns, including human land uses. Their goal should be to restore the total biological, ecological, and cultural landscape diversity, or “ecodiversity,” and its intrinsic and instrumental values of highly valuable, endangered seminatural, agricultural and rural landscapes. For this purpose it is essential to maintain and restore the dynamic flow equilibrium between biodiversity, ecological, and cultural landscape heterogeneity, as influenced by human land uses, which occur at different spatial and temporal scales and intensities. Recent advances in landscape ecology should be utilized for broader assessment of ecodiversity, including proposed indices of ecodiversity, new techniques such as Intelligent Geographical Information Systems (IGIS), and Green Books for the holistic conservation and restoration of valuable endangered landscapes. Restoration ecology can make an important contribution to an urgently needed environmental revolution. This revolution should lead to a new symbiosis between man and nature by broadening the goal of vegetation restoration to ecological and cultural landscape restoration, and thereby to total landscape ecodiversity.     

Metapopulations in multifractal landscapes: on the role of spatial aggregation

The use of fractals in ecology is currently pervasive over many areas. However, very few studies have linked fractal properties of landscapes to generating ecological mechanisms and dynamics. In this study I show that lacunarity (a measure of the landscape texture) is a well suited ecologically scaled landscape index that can be explicitly incorporated in metapopulation models such as the classical Levins equation. I show that the average lacunarity of an aggregated landscape is linearly correlated to the habitat that a species with local spatial processed information may perceive. Lacunarity is a computationally feasible index to measure, and is related to the metapopulation capacity of landscapes. A general approach to multifractal landscapes has been conceived, and some analytical results for self-similar landscapes are outlined, including the specific effect of landscape heterogeneity, decoupled from that of contagion by dispersal. Spatially explicit simulations show agreement with the semi-implicit method presented.     

Mapping functional connectivity

An objective and reliable assessment of wildlife movement is important in theoretical and applied ecology. The identification and mapping of landscape elements that may enhance functional connectivity is usually a subjective process based on visual interpretations of species movement patterns. New methods based on mathematical morphology provide a generic, flexible, and automated approach for the definition of indicators based on the classification and mapping of spatial patterns of connectivity from observed or simulated movement and dispersal events. The approach is illustrated with data derived from simulated movement on a map produced from satellite imagery of a structurally complex, multi-habitat landscape. The analysis reveals critical areas that facilitate the movement of dispersers among habitat patches. Mathematical morphology can be applied to any movement map providing new insights into pattern-process linkages in multi-habitat landscapes.     

A restoration genetics guide for coral reef conservation

Worldwide degradation of coral reef communities has prompted a surge in restoration efforts. They proceed largely without considering genetic factors because traditionally, coral populations have been regarded as open over large areas with little potential for local adaptation. Since, biophysical and molecular studies indicated that most populations are closed over shorter time and smaller spatial scales. Thus, it is justified to re-examine the potential for site adaptation in corals. There is ample evidence for differentiated populations, inbreeding, asexual reproduction and the occurrence of ecotypes, factors that may facilitate local adaptation. Discovery of widespread local adaptation would influence coral restoration projects mainly with regard to the physical and evolutionary distance from the source wild and/or captive bred propagules may be moved without causing a loss of fitness in the restored population. Proposed causes for loss of fitness as a result of (plant) restoration efforts include founder effects, genetic swamping, inbreeding and/or outbreeding depression. Direct evidence for any of these processes is scarce in reef corals due to a lack of model species that allow for testing over multiple generations and the separation of the relative contributions of algal symbionts and their coral hosts to the overall performance of the coral colony. This gap in our knowledge may be closed by employing novel population genetic and genomics approaches. The use of molecular tools may aid managers in the selection of appropriate propagule sources, guide spatial arrangement of transplants, and help in assessing the success of coral restoration projects by tracking the performance of transplants, thereby generating important data for future coral reef conservation and restoration projects.     

Multiple successional pathways in human‐modified tropical landscapes: new insights from forest succession,forest fragmentation and landscape ecology research

Old‐growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human‐modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio‐economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land‐use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio‐temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well‐preserved biodiversity‐rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i) succession must be examined using more comprehensive explanatory models, providing information about the forces affecting not only the presence but also the persistence of species and ecological groups, particularly of those taxa expected to be extirpated from HMTLs; (ii) SS research should integrate new aspects from forest fragmentation and landscape ecology research to address accurately the potential of secondary forests to serve as biodiversity repositories; and (iii) secondary forest stands, as a dynamic component of HMTLs, must be incorporated as key elements of conservation planning; i.e. secondary forest stands must be actively managed (e.g. using assisted forest restoration) according to conservation goals at broad spatial scales.     

Scale‐dependent effects of forest restoration on Neotropical fruit bats

Neotropical fruit bats (family Phyllostomidae) facilitate forest regeneration on degraded lands by dispersing shrub and tree seeds. Accordingly, if fruit bats can be attracted to restoration sites, seed dispersal could be enhanced. We surveyed bat communities at 10 sites in southern Costa Rica to evaluate whether restoration treatments attracted more fruit bats if trees were planted on degraded farmlands in plantations or island configurations versus natural regeneration. We also compared the relative influence of tree cover at local and landscape spatial scales on bat abundances. We captured 68% more fruit bat individuals in tree plantations as in controls, whereas tree island plots were intermediate. Bat activity also responded to landscape tree cover within a 200‐m radius of restoration plots, with greater abundance but lower species richness in deforested landscapes. Fruit bat captures in controls and tree island plots declined with increasing landscape tree cover, but captures in plantations were relatively constant. Individual species responded differentially to tree cover measured at different spatial scales. We attribute restoration effects primarily to habitat structure rather than food resources because no planted trees produced fruits regularly eaten by bats. The magnitude of tree planting effects on fruit bats was less than previous studies have found for frugivorous birds, suggesting that bats may play a particularly important role in dispersing seeds in heavily deforested and naturally regenerating areas. Nonetheless, our results show that larger tree plantations in more intact landscapes are more likely to attract diverse fruit bats, potentially enhancing seed dispersal.     

When is translocation required for the population recovery of old‐growth epiphytes in a reforested landscape?

It is often assumed that species recolonization follows from the restoration of key habitat structure. Thus, forest restoration focuses on the recovery of trees into deforested landscapes, so that a multitude of associated organisms can achieve “colonization credit” and recolonize from remnant source populations into restored habitat. This opportunity for recolonization exists because species vulnerable to habitat loss may experience an “extinction debt,” during which their remnant populations decline only slowly to equilibrium with a deforested landscape. These persistent but declining populations become propagule sources for recolonization. To test limits to “colonization credit,” this study focused on old‐growth dependent lichen epiphytes, using a simulation to identify a hypothetical threshold at which: (1) the number of remnant populations, and (2) their population sizes, are too low to achieve recolonization and population recovery, despite efforts placed into forest restoration. The results show that for a landscape scenario relevant to the industrialized temperate zone, with less than 5% of old‐growth forest remaining, and ambitions for restoration to circa 10–15% forest cover, there is a failure to achieve population recovery over long timescales (i.e. within 600 years), making translocation a necessary option. This delay represents a “colonization deficit” that may be a common feature in ecological restoration more generally.     

城市河流的景观生态学研究:概念框架

城市河流作为城市景观中一种重要的生态廊道,其功能的正常实现与否关系到整个城市的可持续发展。通过分析当前城市河流的研究概况,发现应用景观生态学原理对城市河流展开多尺度、多学科的综合研究是实现“自然-人类-水体”可持续发展的必然趋势。从景观生态学的角度出发,结合城市河流的特点,提出了更为综合的、景观水平上的城市河流研究的概念框架。特别针对景观生态学研究的核心问题,对城市河流的研究尺度、格局分析、干扰程度等重要方面进行了详细论述,以期在景观水平上构建城市河流的可持续发展预案。     

Variable history of land use reduces the relationship to specific habitat requirements of a threatened aquatic insect

The hutchinsonian realized niche of a species is the most common tool for selecting the actions needed when restoring habitats and establishing conservation areas of species. However, defining the realized niche of a species is problematic due to variation across spatial and temporal scales. In this study we tested the hypothesis that habitat parameters defining the realized niche of a species can be derived from a regional study and that national changes in land use influence the perception of the realized niche across different landscapes. We described the realized habitat niche of the threatened dragonfly Leucorrhinia pectoralis, in four Estonian landscapes which all have undergone more than 20 years of habitat degradations. We recorded the presence/absence of L. pectoralis and measured 7 habitat variables for 140 lakes and ponds located in one restored and three un-restored landscapes. Lake size and proportion of short riparian vegetation were significantly positive parameters determining the presence of L. pectoralis across landscape types. The species was much more habitat specific in the restored landscape, with larger influence of other habitat parameters. Our data suggest that the realized niche of the species in the un-restored landscapes was constrained by the present-day habitats. The study demonstrate that if a species realized niche is derived from local distribution patterns without incorporating landscape history it can lead to an erroneous niche definition. We show that landscape restoration can provide knowledge on a species’ habitat dependencies before habitat degradation has occurred, provided that restoration mitigation reflects the former landscape characteristics.     

Designing optimal human‐modified landscapes for forest biodiversity conservation

Agriculture and development transform forest ecosystems to human‐modified landscapes. Decades of research in ecology have generated myriad concepts for the appropriate management of these landscapes. Yet, these concepts are often contradictory and apply at different spatial scales, making the design of biodiversity‐friendly landscapes challenging. Here, we combine concepts with empirical support to design optimal landscape scenarios for forest‐dwelling species. The supported concepts indicate that appropriately sized landscapes should contain ≥ 40% forest cover, although higher percentages are likely needed in the tropics. Forest cover should be configured with c. 10% in a very large forest patch, and the remaining 30% in many evenly dispersed smaller patches and semi‐natural treed elements (e.g. vegetation corridors). Importantly, the patches should be embedded in a high‐quality matrix. The proposed landscape scenarios represent an optimal compromise between delivery of goods and services to humans and preserving most forest wildlife, and can therefore guide forest preservation and restoration strategies.     

Making the connection: expanding the role of restoration genetics in restoring and evaluating connectivity

The success of restoration activities is affected by connectivity with the surrounding landscape. From a genetic perspective, landscape connectivity can influence gene flow, effective size, and genetic diversity of populations, which in turn have impacts on the fitness and adaptive potential of species in restored areas. Researchers and practitioners are increasingly using genetic data to incorporate elements of connectivity into restoration planning and evaluation. We show that genetic studies of connectivity can improve restoration planning in three main ways. First, by comparing genetic estimates of contemporary and historical gene flow and population size, practitioners can establish historical baselines that may provide targets for restoration of connectivity. Second, empirical estimates of dispersal, landscape resistance to movement, and adaptive genetic variance can be derived from genetic data and used to parameterize existing restoration planning tools. Finally, restoration actions can also be targeted to remove barriers to gene flow or mitigate pinch‐points in corridors. We also discuss appropriate methods for evaluating the restoration of gene flow over timescales required by practitioners. Collaboration between restoration geneticists, ecologists, and practitioners is needed to develop practical and innovative ways to further incorporate connectivity into restoration practice.     

Spatial and Temporal Considerations in Restoring Habitat for Wildlife

An accumulated body of theory and empirical evidence suggests that habitat selection by animals is a scale‐dependent, hierarchical process. Hierarchy theory predicts that habitat suitability is influenced by the interaction of factors at multiple spatial scales from the microsite to the landscape and that higher‐order factors impose constraints at lower levels. For instance, large‐scale factors such as landscape context may make a site unsuitable for a species even if the vegetation structure and composition are appropriate. In addition, the spatial arrangement of habitat elements at all scales must be considered when planning restoration efforts. For example, the presence of snags does not ensure that the site will be suitable for snag‐dependent species. The size, age, and spacing of snags and their juxtaposition to other habitat elements must also be considered. Finally, all habitats are dynamic, and therefore the ecological processes that contribute to those dynamics must be maintained or suitable substitutes included in the recovery plan. When considering restoring habitat for wildlife, we recommend that managers: (1) identify the wildlife species they want to target for restoration efforts, (2) consider the size and landscape context of the restoration site and whether it is appropriate for the target species, (3) identify the habitat elements that are necessary for the target species, (4) develop a strategy for restoring those elements and the ecological processes that maintain them, and (5) implement a long‐term monitoring program to gauge the success of the restoration efforts.     

A multiscale analysis of gene flow for the New England cottontail,an imperiled habitat specialist in a fragmented landscape

Landscape features of anthropogenic or natural origin can influence organisms' dispersal patterns and the connectivity of populations. Understanding these relationships is of broad interest in ecology and evolutionary biology and provides key insights for habitat conservation planning at the landscape scale. This knowledge is germane to restoration efforts for the New England cottontail (Sylvilagus transitionalis), an early successional habitat specialist of conservation concern. We evaluated local population structure and measures of genetic diversity of a geographically isolated population of cottontails in the northeastern United States. We also conducted a multiscale landscape genetic analysis, in which we assessed genetic discontinuities relative to the landscape and developed several resistance models to test hypotheses about landscape features that promote or inhibit cottontail dispersal within and across the local populations. Bayesian clustering identified four genetically distinct populations, with very little migration among them, and additional substructure within one of those populations. These populations had private alleles, low genetic diversity, critically low effective population sizes (3.2–36.7), and evidence of recent genetic bottlenecks. Major highways and a river were found to limit cottontail dispersal and to separate populations. The habitat along roadsides, railroad beds, and utility corridors, on the other hand, was found to facilitate cottontail movement among patches. The relative importance of dispersal barriers and facilitators on gene flow varied among populations in relation to landscape composition, demonstrating the complexity and context dependency of factors influencing gene flow and highlighting the importance of replication and scale in landscape genetic studies. Our findings provide information for the design of restoration landscapes for the New England cottontail and also highlight the dual influence of roads, as both barriers and facilitators of dispersal for an early successional habitat specialist in a fragmented landscape.