Lutra 56(2)_Dekker et al_2013

Habitat use by female Geoffroy’s bats (Myotis emarginatus) at its two northernmost maternity roosts and the implications for their conservation

Geoffroy’s bat (Myotis emarginatus) has four known breeding colonies in the Netherlands. Two of these are the known most northerly maternity roosts of the species. Both colonies have received Natura 2000 status. In order to collect ecological data needed to develop a management plan of these two sites, seven female Geoffroy’s bats from these two breeding colonies were radio tagged and tracked during their foraging trips. The animals used woods, stables of cattle and sheep, and tree lanes, to a distance of up to 8 kilometres from the maternity roosts. The animals used tree lanes to fly from their roosts to the hunting areas, but also to forage. They spent the most time in woods (36%), stables (32%), and in tree lanes (29%), the remaining time (2%) was spent in urban areas, open fields and orchards. We did not observe any movement of individuals between the two colonies. The percentage of the night spent in stables was negatively correlated with outside temperature. Based on the ecology of Geoffroy’s bats and the data gathered in the telemetry study, we propose a number of recommendations for protecting these two colonies. These include conserving the breeding colony buildings and adapting management practices in an area of 8 kilometres around the colonies. The most important of these management practices are: conserving tree lines, insect-rich stables and woods In addition, the Dutch and German authorities should cooperate in controlling development projects (construction of roads or estate development) and other projects that may affect these landscape structures.