Are Landscape Configuration Metrics Worth Including When Predicting Specialist and Generalist Bird Species Density? A Case of the Generalised Additive Model Approach

Due to the complexity of factors that influence species density on a large geographical scale, the effectiveness of the species distribution model (SDM) is still debatable. That is why the buffer zone (the area within 100 m from the outside edge of the patch), the core, i.e. (patches excluding the 100 m buffer zone from the patch’s edge) and patch shape are explored in this study to see how they affect the density of habitat specialist and generalist bird species. Two sets of generalised additive models were generated separately for each of the four bird species: One set of models contained landscape configuration metrics as an additional predictor variable, and the other did not. The results showed that models including the core, the buffer zone and the shape of patches turned out to be definitely better than models without them. Specialist species, the Corn bunting and the Wood nuthatch, are more likely to occur in the core of the preferred patches, and they choose those of a simple shape; while generalist species, the Whinchat and the Tree pipit, are more probable to be present in the buffer zone of a more complicated shape. Thus, the results clearly show that specific landscape configuration models can improve the predictive power of SDMs and can be used as an effective tool for predicting species density and functional bird diversity (specialist and generalist). Furthermore, from the applied ecology perspective, detailed landscape configuration metrics can be considered as a surrogate of elusive habitat conditions.     

Generalised Additive Models and Random Forest Approach as effective methods for predictive species density and functional species richness

Environmental and Ecological Statistics - Species distribution modelling (SDM) is a family of statistical methods where species occurrence/density/richness are combined with environmental...     

House sparrows benefit from the conservation of white storks

As with many farmland bird species, the house sparrow Passer domesticus is declining in Europe, mainly due to intensification of agriculture reducing nest sites and food supplies. During 2002–2005, we studied the population size and nest site characteristics of house sparrows breeding within white stork Ciconia ciconia nests in a large area of agricultural landscape within western Poland. To explain sparrow density within stork nests, we examined characteristics of white stork nests (position, age, productivity) and the farm type around the nest. House sparrow density was greatest in the longest established (and hence larger) white stork nests located on traditionally managed farms. Two recent changes appear to have adverse effects on house sparrows. The first is the intensification of farming and the second is active management of white stork nests on electric poles to reduce nest size and thus avoid both disruption to the electrical supply and electrocution of white storks. Because the white stork has such a high profile in Poland, there are numerous schemes to conserve and enhance this species. In conclusion, we clearly show that protecting one species can have valuable, although unplanned, benefits to another species of conservation interest, the house sparrow.