Predicting across scales: Theory development and testing

Landscape ecologists deal with processes that occur at a variety of temporal and spatial scales. The ability to make predictions at more than one level of resolution requires identification of the processes of interest and parameters that affect this process at different scales, the development of rules to translate information across scales, and the ability to test these predictions at the relevant spatial and temporal scales. This paper synthesizes discussions from a workshop on Predicting Across Scales: Theory Development and Testing that was held to discuss current research on scaling and to identify key research issues.     

基于景观生态学的带状公园植物景观美学研究

应用景观生态学理论与方法,提出了城市带状公园绿地植物景观设计的一般以及特殊美学要求,并以甘肃徽县滨河带状公园规划设计为典型案例,提出时移景异、季相突出,情景交融、诗情画意,生态廊道、城市绿脉的植物规划设计理念,阐述构建具有生态美、地方美、文化美的植物景观群落的方法。对干旱、半干旱地区城市带状公园特色的植物景观营造和生态构建做了有意义的探索。     

基于GIS的城市绿地系统景观生态评价

以哈尔滨市群力新区绿地系统为研究对象,在遥感和GIS技术支持下,从绿地类型的基本斑块特征、斑块类型等级、景观异质性及景观破碎化4个层面上选取14个指数,对群力新区绿地景观格局进行分析。结果表明:研究区绿地率低,各类型绿地斑块数分布失衡,面积差异较大,形状复杂程度各异。景观多样性较好,优势度明显,但缺失绿地类型,且分布不均匀,破碎化水平较高。针对研究区绿地景观格局中存在的问题,提出群力新区绿地生态规划建议,使研究区绿地系统具有良好的景观格局,更有效的发挥城市绿地的生态功能。     

Post-fire aspen seedling recruitment across the Yellowstone (USA) Landscape

Landscape patterns of quaking aspen (Populus tremuloides) seedling occurrence and abundance were studied after a rare recruitment event following the 1988 fires in Yellowstone National Park, Wyoming, USA. Belt transects (1 to 17 km in length, 4 m width) along 18 foot trails were surveyed for aspen seedlings on the subalpine plateau of the Park, along gradients of elevation and geologic substrate, during the summer of 1996. Aspen seedling presence and density were characterized as a function of elevation, geologic substrate, slope, aspect, vegetation/cover type, presence of burned forest, and distance to nearest adult aspen stand. Presence of aspen seedlings was best predicted by the incidence of burned forest and proximity to adult aspen; aspen seedlings were only found in burned forest and were more likely to occur closer to adult aspen clones. When tested against independent data collected in 1997, the logistic regression model for aspen seedling presence performed well (overall accuracy = 73%, Tau_p = 0.41). When present, variation in aspen seedling density at local scales (≤ 200 m) was largely explained by elevation, with higher densities observed at lower elevations. At broad scales (> 1 km), seedling density was a function of cover type, elevation, aspect, slope, and burn severity, with greater seedling density in more severely burned forested habitats on southerly, shallow slopes at lower elevations. Aspen seedling densities ranged from 0 to 46,000 seedlings/ha with a median density of 2,000/ha on sites where they occurred. Aspen seedlings were most abundant in the south central and southwest central regions of the park, approximately an order of magnitude less abundant in the southeast region, and nearly absent in the north central area. Establishment of new aspen stands on Yellowstone's subalpine plateau would represent a substantial change in the landscape. However, the long-term fate of these postfire aspen seedlings is not known. This revised version was published online in August 2006 with corrections to the Cover Date.     

Responses of Chilean forest birds to anthropogenic habitat fragmentation across spatial scales

Although it is recognized that anthropogenic forest fragmentation affects habitat use by organisms across multiple spatial scales, there is uncertainty about these effects. We used a hierarchical sampling design spanning three spatial scales of habitat variability (landscape > patch > within-patch) and generalized mixed-effect models to assess the scale-dependent responses of bird species to fragmentation in temperate forests of southern Chile. The abundances of nine of 20 bird species were affected by interactions across spatial scales. These interactions resulted in a limited effect of within-patch habitat structure on the abundance of birds in landscapes with low forest cover, suggesting that suitable local habitats, such as sites with dense understory cover or large trees, are underutilized or remain unused in highly fragmented landscapes. Habitat specialists and cavity-nesters, such as tree-trunk foragers and tapaculos, were most likely to exhibit interactions across spatial scales. Because providing additional sites with dense understory vegetation or large habitat trees does not compensate the negative effect of the loss of forest area on bird species, conservation strategies should ensure the retention of native forest patches in the mixed-use landscapes.     

Landscape effects on mallard habitat selection at multiple spatial scales during the non-breeding period

Previous studies that evaluated effects of landscape-scale habitat heterogeneity on migratory waterbird distributions were spatially limited and temporally restricted to one major life-history phase. However, effects of landscape-scale habitat heterogeneity on long-distance migratory waterbirds can be studied across the annual cycle using new technologies, including global positioning system satellite transmitters. We used Bayesian discrete choice models to examine the influence of local habitats and landscape composition on habitat selection by a generalist dabbling duck, the mallard (Anas platyrhynchos), in the midcontinent of North America during the non-breeding period. Using a previously published empirical movement metric, we separated the non-breeding period into three seasons, including autumn migration, winter, and spring migration. We defined spatial scales based on movement patterns such that movements >0.25 and <30.00 km were classified as local scale and movements >30.00 km were classified as relocation scale. Habitat selection at the local scale was generally influenced by local and landscape-level variables across all seasons. Variables in top models at the local scale included proximities to cropland, emergent wetland, open water, and woody wetland. Similarly, variables associated with area of cropland, emergent wetland, open water, and woody wetland were also included at the local scale. At the relocation scale, mallards selected resource units based on more generalized variables, including proximity to wetlands and total wetland area. Our results emphasize the role of landscape composition in waterbird habitat selection and provide further support for local wetland landscapes to be considered functional units of waterbird conservation and management.     

Surface metrics for landscape ecology: a comparison of landscape models across ecoregions and scales

Context

The patch-mosaic model is lauded for its conceptual simplicity and ease with which conventional landscape metrics can be computed from categorical maps, yet many argue it is inconsistent with ecological theory. Gradient surface models (GSMs) are an alternative for representing landscapes, but adoption of surface metrics for analyzing spatial patterns in GSMs is hindered by several factors including a lack of meaningful interpretations.

Objectives

We investigate the performance and applicability of surface metrics across a range of ecoregions and scales to strengthen theoretical foundations for their adoption in landscape ecology.

Methods

We examine metric clustering across scales and ecoregions, test correlations with patch-based metrics, and provide ecological interpretations for a variety of surface metrics with respect to forest cover to support the basis for selecting surface metrics for ecological analyses.

Results

We identify several factors complicating the interpretation of surface metrics from a landscape perspective. First, not all surface metrics are appropriate for landscape analyses. Second, true analogs between surface metrics and patch-based, landscape metrics are rare. Researchers should focus instead on how surface measures can uniquely measure spatial patterns. Lastly, scale dependencies exist for surface metrics, but relationships between metrics do not appear to change considerably with scale.

Conclusions

Incorporating gradient surfaces into landscape ecological analyses is challenging, and many surface metrics may not have patch analogs or be ecologically relevant. For this reason, surface metrics should be considered in terms of the set of pattern elements they represent that can then be linked to landscape characteristics.

     

Habitat and food supply across multiple spatial scales influence the distribution and abundance of a nocturnal aerial insectivore

Context

Conservation research often focuses on individual threats at a single spatial scale, but population declines can result from multiple stressors occurring at different spatial scales. Analyses incorporating alternative hypotheses across spatial scales allow more robust evaluation of the ecological processes underlying population declines.

Objectives

Populations of many aerially insectivorous birds are declining, yet conservation efforts remain focused on habitat due to an absence of data on changes in prey availability. We evaluate the potential for prey and habitat availability at multiple spatial scales to influence a population of eastern whip-poor-wills (Antrostomus vociferous).

Methods

We assess relationships between landcover (topographical map and satellite imagery) and insect abundance (moths and beetles from blacklight traps), and whip-poor-will distribution and abundance within eastern Canada using Ontario breeding bird atlas data (1980s and 2000s), acoustic recordings (regional), and point counts (local).

Results

Whip-poor-will occurrence in both atlas time periods was positively associated with forest area and fragmentation, but only a delayed effect of urban area explained reductions in detection. Contemporary regional whip-poor-will presence was positively related to moth abundance, and local whip-poor-will abundance was best predicted by area of open-canopy forest, anthropogenic linear disturbance density, and beetle abundance. Our finding that bird presence and abundance were associated with human activity and insect abundance across spatial scales suggests factors beyond habitat structure are likely driving population declines in whip-poor-wills and other aerial insectivores.

Conclusions

This study demonstrates the importance of examining multiple hypotheses, including seasonally and locally variable food availability, across a range of spatial scales to direct conservation efforts.

     

“产业、生态、景观、游憩”四位一体功能的生态农庄规划设计

随着国家对休闲农业的重视以及农村土地流转政策的实施,以"生态农庄"为模式的乡村旅游产品逐渐得到市民的青睐。生态农庄应具备以产业、生态、景观与游憩为"四位一体"的功能。现以江苏阅田生态农庄规划设计为例,从产业规划、生态规划、景观规划以及游憩规划角度出发,研究生态农庄的规划设计。     

Landscape context affects site occupancy of pond-breeding anurans across a disturbance gradient in the Brazilian Cerrado

Context

The Brazilian Cerrado, a global biodiversity hotspot, is being converted to agricultural production. Amphibians in particular are susceptible to agricultural practices that threaten both their wetland and upland habitats. Although local site variables are important for determining species occurrence, site occupancy is also mediated by the broader landscape and management context in which the site occurs.

Objectives

Investigate the relative effects of broad-, intermediate-, and local-scale factors on species occurrence for pond-breeding anurans within different landscapes across an agricultural-disturbance gradient in the Cerrado.

Methods

Ponds were surveyed for adult anurans over 3 years within 18 landscapes (each 625 km²) that varied in their degree of agricultural land use (landscape context). We analyzed species distribution models for eight pond-breeding anurans, using hierarchical binomial generalized linear models.

Results

The broader landscape context had a significant effect on the incidence of pond-breeding anurans, even after accounting for variation in other environmental factors at more local (pond) or intermediate (1-km²) scales. The top-ranked models for most species included some combination of broad-, intermediate- and local-scale factors, however. These covariates influenced species occurrence in different ways, with the response to agricultural disturbance varying among species. Although some species were negatively affected, others appeared to benefit from agricultural activities that increased breeding habitat (e.g., impoundments to provide water for cattle).

Conclusions

Landscape context, the degree to which landscapes have been transformed by agricultural land use, has a major influence on the distribution of pond-breeding anurans in the Brazilian Cerrado.

     

Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest

Context

Dead wood is a key habitat for saproxylic species, which are often used as indicators of habitat quality in forests. Understanding how the amount and spatial distribution of dead wood in the landscape affects saproxylic communities is therefore important for maintaining high forest biodiversity.

Objectives

We investigated effects of the amount and isolation of dead wood on the alpha and beta diversity of four saproxylic species groups, with a focus on how the spatial scale influences results.

Methods

We inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichens on 62 plots in the Sihlwald forest reserve in Switzerland. We used GLMs to relate plot-level species richness to dead wood amount and isolation on spatial scales of 20–200 m radius. Further, we used GDMs to determine how dead wood amount and isolation affected beta diversity.

Results

A larger amount of dead wood increased beetle richness on all spatial scales, while isolation had no effect. For fungi, bryophytes and lichens this was only true on small spatial scales. On larger scales of our study, dead wood amount had no effect, while greater isolation decreased species richness. Further, we found no strong consistent patterns explaining beta diversity.

Conclusions

Our multi-taxon study shows that habitat amount and isolation can strongly differ in the spatial scale on which they influence local species richness. To generally support the species richness of different saproxylic groups, dead wood must primarily be available in large amounts but should also be evenly distributed because negative effects of isolation already showed at scales under 100 m.

     

Predicting connectivity,population size and genetic diversity of Sunda clouded leopards across Sabah,Borneo

Landscape Ecology - The Sunda clouded leopard is vulnerable to forest loss and fragmentation. Conservation of this species requires spatially explicit evaluations of the effects of landscape...     

Influence of landscape structure and stand age on species density and biomass of a tropical dry forest across spatial scales

Three central related issues in ecology are to identify spatial variation of ecological processes, to understand the relative influence of environmental and spatial variables, and to investigate the response of environmental variables at different spatial scales. These issues are particularly important for tropical dry forests, which have been comparatively less studied and are more threatened than other terrestrial ecosystems. This study aims to characterize relationships between community structure and landscape configuration and habitat type (stand age) considering different spatial scales for a tropical dry forest in Yucatan. Species density and above ground biomass were calculated from 276 sampling sites, while land cover classes were obtained from multi-spectral classification of a Spot 5 satellite imagery. Species density and biomass were related to stand age, landscape metrics of patch types (area, edge, shape, similarity and contrast) and principal coordinate of neighbor matrices (PCNM) variables using regression analysis. PCNM analysis was performed to interpret results in terms of spatial scales as well as to decompose variation into spatial, stand age and landscape structure components. Stand age was the most important variable for biomass, whereas landscape structure and spatial dependence had a comparable or even stronger influence on species density than stand age. At the very broad scale (8,000–10,500 m), stand age contributed most to biomass and landscape structure to species density. At the broad scale (2,000–8,000 m), stand age was the most important variable predicting both species density and biomass. Our results shed light on which landscape configurations could enhance plant diversity and above ground biomass.     

How landscape ecology can promote the development of sustainable landscapes in Europe: the role of the European Association for Landscape Ecology (IALE-Europe) in the twenty-first century

In Europe, landscape research has a long tradition of drawing on several disciplines. ‘National schools’ of landscape research developed, which were related to the characteristic landscapes found in the different countries and to specific linguistic meanings and legal traditions when using landscape related concepts. International co-operation demands a certain harmonization of these concepts for better mutual understanding. The 2000 European Landscape Convention provided an important momentum to rethink research, policy and management of landscapes from the perspective of sustainable development and participatory planning. Landscape ecology as a transdisciplinary science with a dynamic and holistic perspective on landscape offers a great potential for an integrative approach. The specificity of the European landscape research rests on its long history and on integration based on the great diversity of the landscapes, characterised by an intimate relationship between the varied natural environment and the different cultural traditions which define the identity of countries, regions and people. Within a unified Europe, with increasing international and trans-border co-operation and increasing common environmental problems, the creation of a specific European Association for Landscape Ecology (IALE-Europe), in addition to the existing international association and its national chapters, became justified by the need for a collaborative endeavour to address the specific problems of landscapes in Europe and to stimulate co-operation between landscape ecologists in research, education and practice.     

Occupancy pattern of a long-horned beetle in a variegated forest landscape: linkages between tree quality and forest cover across spatial scales

Context

Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.

Objectives

We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.

Methods

We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).

Results

Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.

Conclusions

M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.

     

生态与园林交融的绵竹猕猴桃农业园景观设计

生态农业是按照生态学和循环经济理论和原理,利用动物、植物、微生物之间的相互关系,应用现代科学技术和系统方法,形成农业生态环境与经济发展的良性循环.生态农业不仅要满足农业生产要求,还应大力发展农业生态系统中的文化功能.现以绵竹市猕猴桃农业园为例,依据农业生态学原理制定了一个循环农业的产业模式,并将农业生态技术与园林造园艺术相结合,将湿地景观与生态净水相结合,力求营造一个高产、生态、优美和农耕文化浓厚的农业园.