Roost selection by the long-tailed bat, Chalinolobus tuberculatus, in temperate New Zealand rainforest and its implications for the conservation of bats in managed forests

Roost selection by the threatened New Zealand long-tailed bat (Chalinolobus tuberculatus) was examined in temperate beech (Nothofagus) rainforest in N ew Zealand. Seventy-three bats were radio-tracked during the summers of 199 3-1997 to 304 roost cavities in 291 different trees. Roost tree and site ch aracteristics were compared with those of 593 randomly selected trees. Bats selected roosts on the basis of topography, forest composition and tree ch aracteristics. Ninety-five percent of roost trees were in mature, open-stru ctured lowland forest on the relatively flat valley floor within 500 m of t he forest edge. Four tree species (including dead trees) were used as day r oosts. C. tuberculatus did not discriminate between tree species per se, bu t selected roost trees on the basis of functional characteristics associate d with these trees. Bats actively selected taller trees which had relativel y low canopy closure, larger stem diameters, larger trunk surface areas and greater numbers of cavities than random trees. Red beech (Nothofagus fusca ) and dead trees were most likely to provide these preferred characteristic s. Seventy-four percent of roost trees were c. 100- > 600 years of age. Suc h trees are targeted for removal under most forest management practices. Se lection of specialised roosts, high roost lability and low levels of roost re-use indicate that C. tuberculatus need large areas of mature forest. We predict that outside protected areas, the low availability of suitable roos t trees may limit bat populations. (C) 1999 Elsevier Science Ltd. All right s reserved.