Effects of environmental and intrinsic factors on the reproduction of insular European wild rabbits (Oryctolagus cuniculus cuniculus Linnaeus 1758)

Abstract

Abstract European wild rabbits (Oryctolagus cuniculus cuniculus) have been recently recognized as serious crop pests on Lemnos Island, Greece. With an aim to understand the population dynamics, rabbit reproduction was studied in relation to environmental and intrinsic factors, by a postmortem examination of 273 adults (162 males, 111 females), collected from February 2007 to January 2008. Reproductive activity peaked in the spring and was higher in agricultural than in phryganic habitats for females [pregnant: agricultural 74.5%, phryganic 54.0%, p=0.041; average number of implanted embryos: agricultural 5.56±0.21 standard error (SE), phryganic 4.07±0.21 SE, p=0.0002], but not for males (fertile: agricultural 38.8%, phryganic 31.2%, p=0.308). Classification tree models included explanatory variables with monthly time lags to detect important effects. The male reproductive status (i.e. proportion fertile) was favored by a low maximum temperature in the sampling month (<21.5°C), whereas under a higher maximum temperature male fertility was favored by a high vegetation quality (>14.2% crude protein, CP), good body condition and low mean temperature (<20.5°C). A low maximum temperature at conception (<20.0°C; 1 month time lag) favored pregnancy status (i.e. proportion pregnant). At a higher maximum temperature, pregnancy was favored by a high vegetation cover (>86.8%) at conception. Vegetation quality higher than 10.9% CP resulted in a medium to high number of implanted embryos (2 months time lag), further determined by a high vegetation cover (>90.8%; 2 months time lag) and a low population density (<1.9 ind·ha−1). The results identified temperature and habitat quality as prime drivers of reproduction, and ultimately population dynamics. Such information could prove useful for successful rabbit management on Lemnos and other similar areas.