Vegetation structure and prey abundance requirements of the Iberian lynx: implications for the design of reserves and corridors

1. Habitat alteration and fragmentation are two of the greatest threats to biodiversity. The conservation of most species in highly encroached areas r equires reserves that are connected by suitable habitat corridors to increa se the effectiveness of the area under protection. However, the quality req uired for such corridors is still debated. This study investigated the habi tat characteristics (vegetation structure and prey abundance) of sites used by resident and dispersing Iberian lynx in south-western Spain. 2. Vegetation structure and an index of rabbit abundance (the staple prey o f lynx) were measured at sites used by radio-collared lynx in 1996 and 1997 . Data from 128 plots used by resident lynx and 310 plots used by dispersin g individuals were compared with data from 162 randomly located plots in si tes considered to be unused by lynx. 3. Resident sites had a lower percentage of tree cover, shorter tree height , higher percentage of tall shrub cover, higher percentage of overall under storey and higher number of rabbit pellets than both dispersal and unused s ites. The height of the short shrub layer was taller and the rabbit abundan ce index was higher in dispersing sites than in unused sites. 4. Gender did not affect habitat selection by lynx. During dispersal, lynx frequently (50% of cases) used vegetation patches narrower than 300 m. In t hese cases, sites used by lynx had higher understorey cover and taller shru b height than adjacent unused sites. The percentage of short shrub cover us ed by lynx increased with the length of time taken to disperse; this was th e only variable that changed over time. 5. Range size of resident individuals declined significantly with the index of rabbit abundance but increased with the percentage of short shrub cover . Both variables were good predictors of range size. 6. The study shows that corridors connecting reserves do not have to be pri me habitats; they can even support moderate habitat degradation due to huma n activity. This result has implications both for the conservation of exist ing corridors, and for the restoration of the many corridors between reserv es that have been lost.