Seasonal variation in the reproductive activity of the wild rabbit (Oryctolagus cuniculus algirus) in a Mediterranean ecosystem

Abstract

To establish a successful strategy for managing wild rabbit (Oryctolagus cuniculus algirus) populations it is essential to have a clear understanding of reproductive biology. In Portugal, previous work suggested a seasonal pattern of reproductive activity for this species. In this study we present additional information on the seasonal reproductive activity of the wild rabbit as well as data on the influence that environmental factors have on the onset and length of the breeding season. The study was carried out in Pancas, southern Portugal, from October 1997 to September 1998. Rabbits were collected every two months and post mortem analyses were performed. In the males, circulating concentration of testosterone, gonadal weight, daily sperm production, diameter of the seminiferous tubules and the thickness of epithelial cells were measured. The numbers of corpora lutea, embryos and placental scars were recorded in the females. To assess abundance and quality of food, samples of herbaceous vegetation were collected and analysed for water, fibre and crude protein content. The reproductive season extended from November to June with a peak in March/April, with both sexes showing an annual cycle of gonadal development and subsequent regression. All analysed females were pregnant and/or lactating between March and June. The mean litter size estimated by counting the embryos in the uteri was 3.90 ± 0.50. Daily sperm production was highest between November and April. Testicular function was strongly correlated with environmental temperature and the water content of the vegetation, and both testicular and ovarian development were correlated with vegetation biomass.

Hunting for answers: rabbit (Oryctolagus cuniculus) population trends in northeastern Spain

“…It is therefore likely that the average hunting pressure documented in our study is based on lower numbers than occurred during the early and mid 1990s. This is not the first time that hunting activities have been examined in relation to rabbit survival in the Iberian Peninsula (Gonçalves et al 2002;Angulo and Villafuerte 2003). As mentioned earlier, for simplicity, our study estimated hunting pressure as hunters per square kilometer and suggested that recovering populations are associated with fewer hunters in an area.…”

“…However, management can simply change the time of hunting without changing hunting pressure. Changing the time of year that rabbits are currently hunted from winter to late spring or summer has been suggested in Spain (Angulo and Villafuerte 2003) and Portugal (Gonçalves et al 2002). Both of these studies contended that changing the hunting season to fit around the main breeding season of the rabbit in the beginning of the year will minimize the killing of adult rabbits of high reproductive value, thereby increasing the growth rate of the population.…”

Influence of habitat management on the abundance and diet of wild rabbit (Oryctolagus cuniculus algirus) populations in Mediterranean ecosystems

“…In the managed areas, reproductive parts of plants were also more frequently ingested. Particularly in autumn and spring, these correspond to important dietary components, for their high water and protein content, essential for reproduction (Gonçalves et al 2002). Spontaneous graminoides, like D. glomerata, were also present in high frequencies at different moments in all study sites, suggesting that in this region this could be an essential trophic component for the wild rabbit, probably due to the plant's high palatability and nutritional value (Marques and Mathias 2001).…”

Rabbit Oryctolagus Cuniculus Habitats in Mediterranean Scrubland: The Role of Scrub Structure and Composition

“…after the end of the breeding season (Gonçalves et al 2002), by systematically searching for activity signs (footprints, faecal pellets, scratches and direct observation of animals) along the network of dirt roads and firebreaks crossing the study area. These tracks provided the main discontinuities in otherwise densely vegetated terrain where rabbit signs appeared largely absent and systematic surveys were virtually impossible.…”