In tro duc tionThe wild boar Sus scrofa Linnaeus, 1758 is cur rently in creas ing its abun dance in Eu rope and other parts of the world Tellería 1986, Gipson et al. 1998). This suid is the most widely dis trib uted wild un gu late in the Ibe rian Pen in sula (Rosell and Herrero 2002), where both its range and den si ties are in creasing Tellería 1986, Gortázar et al. 2000).The re cent in crease in wild boar pop u la tions in many Eu ro pean coun tries is thought to be a [327]

Aim This paper describes the dispersal process of roe deer (Capreolus capreolus Linnaeus, 1758) with respect to climatic factors, landscape characteristics and human activity. We hypothesized that environmental characteristics constrain the relative abundance and dispersal process of roe deer.Location The study was conducted in the Iberian Mountains, north-eastern Spain, during 1986-2000.Methods Roe deer colonization dates in the study area were obtained from a survey for large mammals and from direct interviews with the employees of the Fish and Game Agency. We used a 10 · 10 km UTM grid as the sampling unit (n ¼ 91). The relative abundance of roe deer was estimated by counting the number of pellet groups in line transects, which were representative of the habitat availability in the 10 · 10 km UTM grid. Climatic factors were obtained from meteorological stations placed near to the plot. Landscape structure indices, topography and human activity factors were obtained from digital maps using fragstats 3.3 and idrisi 32. We discarded a number of variables with no statistical significance and avoided multicollinearity by using Spearman rank correlation. Then, we used GLMz (with a multinomial error distribution and a logit link function) to analyse the influence of each variable considered in the dispersal process. Finally, GLMz (with a binomial error distribution and a logit link function) were used a posteriori to differentiate between the effects of the explanatory factors on a particular phase of the dispersal process. ResultsOur results indicate that proximity to a previously colonized grid significantly affected the global process of roe deer colonization. Independently of the proximity of the nearest population in the previous phase of colonization, our results also indicated that the dispersal process was influenced by precipitation and landscape structure, leading the species to colonize even apparently hostile places. Original nuclei of these populations occurred in territories with high and constant precipitation, and a landscape formed by mosaics of agricultural land with a high proportion of forests. During the expansion process, roe deer colonized territories with summer droughts, dominated by large agricultural patches and with few forest patches.Main conclusions These data support the working hypothesis that environmental characteristics constrain roe deer relative abundance and dispersal process through the Iberian Mountains. The location of the original nuclei of these populations probably had environmental conditions that were more favourable for the roe deer. Areas settled in the final phases of the dispersal process had low relative abundances of roe deer, and are likely to act mainly as dispersal corridors rather than being able to sustain viable populations themselves.

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Some populations of European wild rabbit (Oryctolagus cuniculus) in Spain have recovered after rabbit hemorrhagic disease, but others (the majority) have not recovered. The European wild rabbit is a keystone species in Spain's Mediterranean ecosystems, and several factors have been studied to determine what will stabilize populations and possibly propagate recovery. Many of the previous efforts to determine these pivotal factors have been short-term studies focused on few localities. Most management efforts and studies focused on the wellpreserved habitats of southwestern Spain. Our objective was to examine spotlight counts from 60 localities over the past 13 years following the arrival of rabbit hemorrhagic disease in Aragón, northeastern Spain, to estimate rabbit population trends using linear regressions. The number of rabbits seen was transformed into a rough kilometric abundance index. With this data, we calculated a population trend index only for those localities with 6 or more years of data (n=42). No clear population trends were observed for the study period at a regional scale [X ±SE, range]; (0.065±0.081 from −0.860 to 0.915). We also examined factors that potentially influence regional rabbit population trends, including vegetation, topography, soil softness, climate, predator population trends, and hunting pressure. Our results indicate that rabbit trends have their strongest positive correlation with low hunting pressure and are negatively affected in areas of hard soils. In Aragón, the best populations of endangered raptors are concentrated in the Central Valley, which is the same area where rabbit populations are currently increasing.

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