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Following the introductions carried out in late 1960s, Eastern cottontail Sylvilagus floridanus Allen, 1890 rapidly colonized the Po Plain (northern Italy), following the Po River and its tributaries. We monitored a cottontail population using the line-transect method from autumn 2005 to spring 2009 in a 8.2-km2 study area located along the Po River, and we investigated species habitat requirements by assessing the presence/absence of faecal pellets in 200 randomly distributed plots from September 2006 to August 2007 and by Resource Selection Probability Function through logistic regression analyses and multi-model inference. The cottontail population varied dramatically over time in size, with a great drop at the end of the breeding period. Cottontails selected foraging habitats at the macro- and micro-scales, with some differences among seasons. Two macro-habitat variables differed significantly between used and unused plots through seasons: arboriculture stands were always greater in presence plots, whereas winter cereals were always greater in absence ones. On the macro-level, woody and herbaceous habitats, such as fallow fields, characterized presence plots. At the micro-habitat level, presence plots were associated with permanent dense cover except during summer. Several logistic regression models were built through seasons and ranked using the Akaike’s Information Criterion. Arboriculture stands enhanced cottontail presence mostly during the growing season contrary to crop fields. Hedgerows were used according to availability during feeding activity. Cottontail habitat selection varied according to seasonal changes in resource availability and suitability of the different habitat types.
In northern Italy, the range of the Eastern cottontail (Sylvilagus floridanus) largely overlaps with that of the native European hare (Lepus europaeus) on the Po Plain. Both species appear to have similar habitat requirements. We studied habitat selection by hares and cottontails during feeding activity from September 2006 to August 2007 in two areas where they occur alone (allopatry) and in one area where they occur together (sympatry). The three areas were basically similar, so that shifts in habitat use observed in sympatry should reflect the response to interspecific competition. Habitat selection was examined at micro- and macro-habitat levels throughout seasons. Habitat breadth of both species followed the change of resource availability through seasons in allopatry as well as in sympatry. No shifts in habitat use were evident at macro-habitat level, even during autumn which was the limiting season. Exploitation of shared habitats by the two species seems to be promoted by differential micro-habitat use within macro-habitat types. Cottontails used woods with dense understory in greater proportion than hares, and their present sites were concentrated within the maximum distance of 20 m of the nearest shelter site. Hares were more likely than cottontails to exploit crops, and their sites were distributed even greater than 80 m away from permanent cover patches. The habitat heterogeneity of agricultural ecosystems within the sympatry range could buffer the negative effects of external factors (climate, human disturbance and predation) on hares, and enhance the chances of exploitation of shared habitats by both species.
Mexico has eight endemic lagomorph species, several of which are endangered. For conservation reasons it is necessary to know more about their diet. In a first step we applied the method of fecal pellet analysis to the cottontailSylvilagus floridanus (Allen, 1890). Since it is common in Mexico, information on its diet should provide a useful baseline with which to compare the diets of other Mexican lagomorphs. At Ixtacuixtla, we recorded vegetation and analyzed fecal pellet content once in August (wet season) and once in March (dry season) at 4 sampling sites representing different habitat types. The comparison of vegetation and diet records suggestedS. floridanus to occupy the same dietary niche in the different habitats. Measures of niche breadth showedS. floridanus to be neither a generalist nor a specialist. Nevertheless, it appeared to be quite selective in consuming particular herb and grass species even when they became scarce during the dry season. Since the vegetation record only poorly represented the rabbits’ diet, a more focused approach is suggested for future studies: first, to identify the relevant food species in the diet, second, to obtain data on the availability of these, and third, to concentrate on time points when changes in resource state could be a limiting factor.
In northern Italy, the native European hare (Lepus europaeus) and the introduced Eastern cottontail (Sylvilagus floridanus) can occur together at a local scale, as a result of cottontail introduction and expansion into the European hare range. Hare populations are limited in Italy by habitat loss, diseases, and most important by overhunting, and many areas within hare range in northern Italy are undergoing increasing anthropogenic impact. Therefore, quantitative studies on resource selection and exploitation by both species will be of great interest to evaluate the degree of habitat overlap and to search for exploitation competition evidences. We studied habitat selection during resting time by both species in two areas where they occur alone and in one area where they occur together. Habitat selection by the two species was examined at micro- and macro-habitat scales during autumn–winter and spring–summer. Both species selected ecotonal zones between arboriculture stands and crops and between arboriculture stands and spontaneous vegetation (i.e., herbaceous, bush, and woody permanent species), which were the less available in the area of sympatry. No habitat shifts were evident at macro-habitat level because the two species showed a differential micro-habitat use within patches. On the whole, it seems that habitat heterogeneity promoted daytime segregation between the two species. In particular, edges between crops and canopy habitats should be improved, thus reducing chance of intra- and inter-specific encounters.
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