Comparison of 3 methods to estimate rabbit abundance in a Mediterranean environment

European rabbits (Oryctolagus cuniculus) are of special concern, for differ ent reasons. They are prey of many predators in Mediterranean ecosystems, a n important game species, and even a pest that causes economic losses. Henc e, estimate of population abundance is a major interest for conservation ma nagement and control programs. I estimated abundance of European rabbits in 6 different habitats by line transect sampling, pellet count, and warren c ount. Rabbits were most abundant in Mediterranean scrubland, closely follow ed by ash stands. Pastureland, lentiscus in plantations, and pine plantatio ns had 3, 7, and 27 times fewer rabbits than the Mediterranean scrubland, r espectively. Abundance determined by pellet counts corroborated results obt ained by line transect sampling, except in the Mediterranean scrubland habi tat, where number of pellets was less than expected. There was a significan t correlation between number of pellets and rabbit density when data from t he Mediterranean scrubland were replaced by data from pellet counts perform ed at the edge of the Mediterranean scrubland. Number (mean+/-SE) of warren s/100 m of transect was greatest for Mediterranean scrubland (3.5+/-0.5) an d least for pastureland (0.6+/-0.2). Number of entrances/warren also differ ed among habitats; warrens in the pastureland had more entrances (11+/-1.2) than warrens in other habitats (between 5.5+/-0.6 and 9.0+/-1.2). Entrance s were used more during spring (54.8%+/-4.3-74.6%+/-2.4) than during summer ; the only habitat where entrances were used regularly in summer was the pa stureland (54.6%+/-4.2 of entrances). Counting pellets and warrens can prov ide reliable estimates of rabbit abundance.