Ranging behaviour of translocated roe deer in a Mediterranean habitat: seasonal and altitudinal influences on home range size and patterns of range use

Abstract

In this study we investigated the causes of seasonal variation in the home ranges of roe deer reintroduced to the Gardunha Mountains (Portugal). From May 2002 to April 2003, 1 year after the animals had been released, we collected data using radio-tracking techniques for five monitored animals (two males and three females). We found differences in the size of home ranges between seasons, with home ranges larger in summer than winter (minimum convex polygon peeled to 95%: summer 409.64"98.20 ha, winter 116.20"17.90 ha). This is contrary to evidence from central and northern Europe, where home ranges are typically larger in winter than summer. Moreover, two of the sampled females and one of the males tended to use higher elevations in summer. Comparisons between Mediterranean populations and those in central and northern Europe showed that Mediterranean populations in the winter easily fulfil their needs within a small area, whereas in the hot dry summer a larger area is needed. Furthermore, individuals prefer a higher, cooler mountainous habitat in summer, which is likely to be a means of avoiding warmer temperatures.

Factors affecting roe deer occurrence in a Mediterranean landscape, Northeastern Portugal

“…The abundance of roe deer pellet groups was investigated at a wide spatial scale (buffer with 12.6-km population scale) and a home range scale (buffer with 1.26 km). The smallest buffer (1.26 km), termed home range, was calculated based on home ranges values found by Carvalho et al (2008), in Portugal and in similar Mediterranean habitat types (Lamberti et al 2006). The largest buffer (12.6 km) represents a wider spatial scale, representing how the surrounding landscape potentially affected roe deer occurrence.…”

“…It is unknown however, which factors shape roe deer distribution in the mosaic Mediterranean landscapes, such as those occurring in the north of Portugal. This population of roe deer is undoubtedly of high conservation and ecological interest since it: (i) occupies the edge of its southwestern distribution range (Holt and Keitt 2005); (ii) occurs at low densities and is thus relatively prone to extinction as a consequence of potential environmental changes (Lande 1993); (iii) occupies a Mediterranean ecosystem, completely different from the well studied populations of central and northern Europe (Carvalho et al 2008) and (iv) constitutes the main wild prey for the endangered Iberian wolf Canis lupus signatus (Vos 2000). Most of the information of the effect of predators (e.g.…”

Roe deer reintroduction in central Portugal: a tool for Iberian wolf conservation

“…The values vary between 1 and 9 (factor on the vertical axis is more important than the factor on the horizontal axis) or 1/3 and 1/9 (factor on the vertical axis is less important than the factor on horizontal axis). (Rosell et al 1996;Carvalho et al 2008).…”

“…macro-habitat, landscape structure variables, as well as human disturbance and topographic factors). The smallest buffer (1.26 km), termed the home range, was calculated based on home range values in Portugal reported by Carvalho et al (2008) and in similar Mediterranean habitats (Rosell et al 1996, Lamberti et al 2006. The largest buffer (12.6 km) represents a wider spatial scale and indicates how the surrounding landscape potentially affected roe deer occurrence.…”

“…Some animals will be fitted with GPS collars and the information obtained by this method will be related to other ecological issues related to the project. Although studies with telemetry (GPS) in roe deer are common in the rest of Europe, in Portugal this technique has not been used for this species (but see Carvalho et al 2008). The information obtained will not only be used to improve potential habitat models and predict population expansion, but will also be of use to develop an adaptive management plan crucial to such reintroduction initiatives (Sarrazin & Barbault 1996).…”