Rabbit warren distribution in relation to pasture communities in Mediterranean habitats: consequences for management of rabbit populations

Abstract

Iberian wild rabbit numbers have decreased in the last decades. The management implemented to recover rabbit populations includes several techniques, one of the most common being the construction of artificial rabbit warrens. To optimally distribute the artificial warrens in the field it is essential to understand natural warren microhabitat. Few studies have investigated the relationship between rabbits and grassland communities. In this work we study the spatial distribution and characteristics of rabbit warrens as well as their relation to grasslands in Mediterranean woodlands of central Spain. During the summer of 2001, three 12.5-ha study plots, including the most representative grassland communities of the area, were selected. All rabbit warrens were surveyed and the active and total entrances, shrub cover, grassland community and warren cover type were characterised. A grassland community selection index was calculated and the warren spatial distribution analysed. Ploughed lands and shallow soils were unsuitable for warren establishment. The mean number of burrow entrances per warren was 5.8 (4.4 active), and warren clustering occurred only in ploughed plots. However, pasture communities composed of annual and perennial species growing on unploughed deep sandy soils were preferentially selected. Most warrens (81.4%) were dug under some kind of protection such as shrub roots and rocks. According to our results, when designing rabbit restocking programs that include the provision of artificial warrens, unploughed deep soils with plenty of shrubs and rocks should be preferentially selected to locate the artificial warrens, which should be spaced so there are ~10 warrens per hectare and ~5–6 burrow entrances per warren.