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Appropriate Spatial Scale (appropriate + spatial_scale)
Selected AbstractsModelling species distributions in Britain: a hierarchical integration of climate and land-cover dataECOGRAPHY, Issue 3 2004Richard G. Pearson A modelling framework for studying the combined effects of climate and land-cover changes on the distribution of species is presented. The model integrates land-cover data into a correlative bioclimatic model in a scale-dependent hierarchical manner, whereby Artificial Neural Networks are used to characterise species' climatic requirements at the European scale and land-cover requirements at the British scale. The model has been tested against an alternative non-hierarchical approach and has been applied to four plant species in Britain: Rhynchospora alba, Erica tetralix, Salix herbacea and Geranium sylvaticum. Predictive performance has been evaluated using Cohen's Kappa statistic and the area under the Receiver Operating Characteristic curve, and a novel approach to identifying thresholds of occurrence which utilises three levels of confidence has been applied. Results demonstrate reasonable to good predictive performance for each species, with the main patterns of distribution simulated at both 10 km and 1 km resolutions. The incorporation of land-cover data was found to significantly improve purely climate-driven predictions for R. alba and E. tetralix, enabling regions with suitable climate but unsuitable land-cover to be identified. The study thus provides an insight into the roles of climate and land-cover as determinants of species' distributions and it is demonstrated that the modelling approach presented can provide a useful framework for making predictions of distributions under scenarios of changing climate and land-cover type. The paper confirms the potential utility of multi-scale approaches for understanding environmental limitations to species' distributions, and demonstrates that the search for environmental correlates with species' distributions must be addressed at an appropriate spatial scale. Our study contributes to the mounting evidence that hierarchical schemes are characteristic of ecological systems. [source] Linking ecological theory with stream restorationFRESHWATER BIOLOGY, Issue 4 2007P. S. LAKE Summary 1. Faced with widespread degradation of riverine ecosystems, stream restoration has greatly increased. Such restoration is rarely planned and executed with inputs from ecological theory. In this paper, we seek to identify principles from ecological theory that have been, or could be, used to guide stream restoration. 2. In attempts to re-establish populations, knowledge of the species' life history, habitat template and spatio-temporal scope is critical. In many cases dispersal will be a critical process in maintaining viable populations at the landscape scale, and special attention should be given to the unique geometry of stream systems 3. One way by which organisms survive natural disturbances is by the use of refugia, many forms of which may have been lost with degradation. Restoring refugia may therefore be critical to survival of target populations, particularly in facilitating resilience to ongoing anthropogenic disturbance regimes. 4. Restoring connectivity, especially longitudinal connectivity, has been a major restoration goal. In restoring lateral connectivity there has been an increasing awareness of the riparian zone as a critical transition zone between streams and their catchments. 5. Increased knowledge of food web structure , bottom-up versus top-down control, trophic cascades and subsidies , are yet to be applied to stream restoration efforts. 6. In restoration, species are drawn from the regional species pool. Having overcome dispersal and environmental constraints (filters), species persistence may be governed by local internal dynamics, which are referred to as assembly rules. 7. While restoration projects often define goals and endpoints, the succession pathways and mechanisms (e.g. facilitation) by which these may be achieved are rarely considered. This occurs in spite of a large of body of general theory on which to draw. 8. Stream restoration has neglected ecosystem processes. The concept that increasing biodiversity increases ecosystem functioning is very relevant to stream restoration. Whether biodiversity affects ecosystem processes, such as decomposition, in streams is equivocal. 9. Considering the spatial scale of restoration projects is critical to success. Success is more likely with large-scale projects, but they will often be infeasible in terms of the available resources and conflicts of interest. Small-scale restoration may remedy specific problems. In general, restoration should occur at the appropriate spatial scale such that restoration is not reversed by the prevailing disturbance regime. 10. The effectiveness and predictability of stream ecosystem restoration will improve with an increased understanding of the processes by which ecosystems develop and are maintained. Ideas from general ecological theory can clearly be better incorporated into stream restoration projects. This will provide a twofold benefit in providing an opportunity both to improve restoration outcomes and to test ecological theory. [source] An ecosystem-scale predictive model of coastal seagrass distributionAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2010A. Grech Abstract 1.Maintaining ecological processes that underpin the functioning of marine ecosystems requires planning and management of marine resources at an appropriate spatial scale. 2.The Great Barrier Reef World Heritage Area (GBR) is the world's largest World Heritage Area (approximately 348,000,km2) and second largest marine protected area. It is difficult to inform the planning and management of marine ecosystems at that scale because of the high cost associated with collecting data. To address this and to inform the management of coastal (approximately 15,m below mean sea level) habitats at the scale of the GBR, this study determined the presence and distribution of seagrass by generating a Geographic Information System (GIS)-based habitat suitability model. 3.A Bayesian belief network was used to quantify the relationship (dependencies) between seagrass and eight environmental drivers: relative wave exposure, bathymetry, spatial extent of flood plumes, season, substrate, region, tidal range and sea surface temperature. The analysis showed at the scale of the entire coastal GBR that the main drivers of seagrass presence were tidal range and relative wave exposure. Outputs of the model include probabilistic GIS-surfaces of seagrass habitat suitability in two seasons and at a planning unit of cell size 2,km×2,km. 4.The habitat suitability maps developed in this study extend along the entire GBR coast, and can inform the management of coastal seagrasses at an ecosystem scale. The predictive modelling approach addresses the problems associated with delineating habitats at the scale appropriate for the management of ecosystems and the cost of collecting field data. Copyright © 2010 John Wiley & Sons, Ltd. [source] Wildlife habitat strips and native forest ground-active beetle assemblages in plantation nodes in northeast TasmaniaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2005Simon Grove Abstract, In Tasmania, plantation establishment is often concentrated in ,nodes', a practice that can result in a high degree of fragmentation of remaining native forest in these areas. In this study we examined the sensitivity of ground-active beetles to the effects of conversion of native forest to plantation in which remaining native forest is largely confined to narrow wildlife habitat strips. At five damp sclerophyll forest sites in northeast Tasmania, pitfall sampling was carried out along the middle axis of a wildlife habitat strip, in the young plantation surrounding the strip, and at three distances in from the edge of nearby continuous native forest. The study documented a rich fauna, particularly for carabids. Species composition varied among sites, emphasising the need for adequate regional reservation of native forest at appropriate spatial scales. While plots in plantations and strips supported similar numbers of species as continuous native forest, they usually differed in assemblage composition. In general, assemblages in strips appeared to be intermediate in composition between those of continuous native forest and plantations. Significant differences corresponding to a progressive change in assemblage composition with distance into continuous native forest from its edge were detected for one, possibly two, sites. Plots in strips were generally more similar in assemblage composition to those near the edge of continuous native forest than to those towards its interior. Within the study area, strips may promote the survival of species that otherwise associate with the edges of continuous native forest, but they may provide less effective habitat for species that associate with native forest interiors. However, they still harbour many native forest species which are rare or absent in plantations. Although only based on a short-term sampling program, the study implies that future strips in Tasmanian damp sclerophyll forest could better benefit some forest interior species if prescriptions were to specify wider strips. However, a clearer conservation outcome might be to ensure the continuance of a sufficiently comprehensive, adequate and representative network of native forest formal reserves (in addition to wildlife habitat strips) containing damp sclerophyll forest. These should be large enough to cater for forest interior species, and dispersed at a spatial scale appropriate to the rate of species turnover found among ground-active beetle assemblages in these forests. [source] | ||||||||||