Search results for "Spatial"
showing 10 items of 2121 documents
Spatial patterns of woody plant and bird diversity: functional relationships or environmental effects?
2008
Aim To understand cross-taxon spatial congruence patterns of bird and woody plant species richness. In particular, to test the relative roles of functional relationships between birds and woody plants, and the direct and indirect environmental effects on broad-scale species richness of both groups. Location Kenya. Methods Based on comprehensive range maps of all birds and woody plants (native species > 2.5 m in height) in Kenya, we mapped species richness of both groups. We distinguished species richness of four different avian frugivore guilds (obligate, partial, opportunistic and non-frugivores) and fleshy-fruited and non-fleshy-fruited woody plants. We used structural equation modelli…
Spatial autocorrelation and the selection of simultaneous autoregressive models
2007
Aim Spatial autocorrelation is a frequent phenomenon in ecological data and can affect estimates of model coefficients and inference from statistical models. Here, we test the performance of three different simultaneous autoregressive (SAR) model types (spatial error = SAR err , lagged = SAR lag and mixed = SAR mix ) and common ordinary least squares (OLS) regression when accounting for spatial autocorrelation in species distribution data using four artificial data sets with known (but different) spatial autocorrelation structures. Methods We evaluate the performance of SAR models by examining spatial patterns in model residuals (with correlograms and residual maps), by comparing model para…
Species richness of migratory birds is influenced by global climate change
2007
Aim Global climate change is increasingly influencing ecosystems. Long-term effects on the species richness and composition of ecological communities have been predicted using modelling approaches but, so far, hardly demonstrated in the field. Here, we test whether changes in the composition of bird communities have been influenced by recent climate change. Location Europe. Methods We focus on the proportion of migratory and resident bird species because these groups are expected to respond differently to climatic change. We used the spatial relationship between climatic factors and bird communities in Europe to predict changes in 21 European bird communities under recent climate change.…
Impact of climate change on migratory birds: community reassembly versus adaptation
2007
Aim Species can respond to global climate change by range shifts or by phenotypic adaptation. At the community level, range shifts lead to a turnover of species, i.e. community reassembly. In contrast, phenotypic adaptation allows species to persist in situ , conserving community composition. So far, community reassembly and adaptation have mostly been studied separately. In nature, however, both processes take place simultaneously. In migratory birds, climate change has been shown to result in both exchange of species and adaptation of migratory behaviour. The aim of our study is to predict the impact of global climate change on migratory bird communities and to assess the extent to which …
The global distribution of frugivory in birds
2009
Aim To examine patterns of avian frugivory across clades, geography and environments. Location Global, including all six major biogeographical realms (Afrotropics, Australasia, Indo-Malaya, Nearctic, Neotropics and Palaearctic). Methods First, we examine the taxonomic distribution of avian frugivory within orders and families. Second we evaluate, with traditional and spatial regression approaches, the geographical patterns of frugivore species richness and proportion. Third, we test the potential of contemporary climate (water–energy, productivity, seasonality), habitat heterogeneity (topography, habitat diversity) and biogeographical history (captured by realm membership) to explain geo…
The Role of Spatial Plans Adopted at the Local Level in the Spatial Planning Systems of Central and Eastern European Countries
2022
The article deals with the issue of spatial plans at the local level. The aims of this paper are (1) extracting the characteristics of local spatial plans that can be compared more broadly (2) identifying, on this basis, the role of spatial plans at the local level in the countries of Central and Eastern Europe (CEE). In achieving these aims, the authors have critically examined spatial plans and their performance, as well as the planning systems they belong to. Hence, they have investigated the types of local plans in each country, their legal features, and the layout of their content. This examination has revealed a host of problems in the workings of the CEE planning systems. The article…
Scale-related patterns in the spatial and environmental components of stream macroinvertebrate assemblage variation
2007
Aim We examined the relative contributions of spatial gradients and local environmental conditions to macroinvertebrate assemblages of boreal headwater streams at three hierarchical extents: bioregion, ecoregion and drainage system. We also aimed to identify the environmental variables most strongly related to assemblage structure at each study scale, and to assess how the importance of these variables is related to regional context and spatial structuring at different scales. Location Northern Finland (62–68° N, 25–32° E). Methods Variation in macroinvertebrate data was partitioned using partial canonical correspondence analysis into components explained by spatial variables (nine terms…
Disentangling the effects of area, energy and habitat heterogeneity on boreal forest bird species richness in protected areas
2009
Aim One of the few general laws in ecology is that species richness is a positive function of area. However, it has been proposed that area would merely be a proxy for energy. Additionally, habitat heterogeneity has been found to be an important factor determining species richness. Yet the relative importance of those relationships is little known, and it is still unclear how they are brought about. We aimed to dissect which factors drive the species richness of boreal forest birds, and to identify the most probable mechanisms. Location Forested protected areas in Finland. Methods Using bird line census data collected in 104 protected areas, we ran simultaneous autoregressive models to e…
Geographical Distribution of Unemployment: An Analysis of Provincial Differences in Italy
2007
Unemployment rates appear to vary widely at a subregional (e.g., local or provincial) level. Using spatial econometric models for spatial autocorrelation, this paper focuses attention on the spatial structure of regional unemployment disparities of Italian provinces. On the basis of findings from the economic literature and of the available socio-economic data, various model specifications including different explanatory variables are tested to investigate the geographical distribution of unemployment in the 103 provinces of Italy for the years 1998 and 2003. The results suggest that there is a clear explanation of unemployment differentials in terms of spatial equilibrium and disequilibriu…
The Local versus Global Dilemma of the Effects of Structural Funds
2011
This paper extends the analysis by Dall'erba and Le Gallo dealing with the impact of structural funds on the growth process of European regions. Like most of the other 18 contributions assessing the efficiency of structural funds, our article was based on a global model of b-convergence: one coefficient pertaining to the structural funds variable was estimated for the whole sample. In this paper, we extend this approach by performing local estimations, where one coefficient is estimated for each region, so that the impact of structural funds can be regionally differentiated. As in the previous contribution, the presence of spatial spillover effects is taken into account using spatial econom…