5. Individual responses of bats to habitat selection

Bats respond differently to roosts as well as foraging habitats (or home ranges) according to their reproductive state. The energy needs of reproductive females are such that they become a lot more demanding than the other individuals [82]. Myotis bechsteinii and Plecotus auritus which are two ecologically and morphologically similar species illustrate this different use of available resources influenced by their reproductive status. Pregnant females of M. bechsteinii have smaller home ranges than non-reproductive females, change roost frequently often selecting roosts high in the trees and entering into a torpor when meteorological conditions deteriorate [31, 82]. Then, lactating females and young forage over high-quality habitats while non-reproductive females forage in lower-quality habitats such as conifer or young broadleaved stands. Social exchanges take precedence when selecting roosts, with colonies settling in large cavities without much vegetation clutter at the entrance allowing for several individuals to leave and enter the roost at a time [32]. On the contrary, pregnant females of P. auritus use large home ranges and can roost alone in a tree far from the main colony for several days. Lactating females systematically stay within the colony, foraging in good-quality habitats close to the cavity. Non-reproductive females use the same types of habitats but forage further from the colony [31]. Thus, the conservation of a network of cavities is clearly crucial for both species, including the preservation of woodpecker hollows at elevated positions on trees for M. bechsteinii. The same advice applies to other species with behavioural differences in the utilisation of tree cavities and habitat selection in Europe such as Myotis daubentonii [64] and Myotis nattereri [31], and on other continents, such as Myotis septentrionalis [65], Eptesicus fuscus [74], Chalinolobus tuberculatus [70, 83] and Mystacina tuberculata [84].
