Spatial ecology and pollination services of the lesser short-tailed bat (Mystacina tuberculata) in Pureora Forest, New Zealand

Abstract

Recent research shows that lesser short-tailed bats (Mystacina tuberculata) are more important pollinators of native plants than was previously thought. Therefore, it is imperative that the extent of pollination services provided by M. tuberculata is further explored so that a more comprehensive understanding of its contribution to the ecology of New Zealand forests is achieved. The single study to have investigated the relative contribution of M. tuberculata to the pollination of a variety of native plants was conducted on one of the few M. tuberculata populations inhabiting the comparatively pristine ecosystem of Little Barrier Island (Hauturu). Given that M. tuberculata now highly restricted in its geographic range and many populations occur in fragmented landscapes, it is of particular importance to gain knowledge of the bats pollination services in modified ecosystems. Therefore, the aim of this study was to better understand the patterns of space use of M. tuberculata and its contribution to pollination of native plants in the Pureora Forest, a fragmented forest on mainland New Zealand where M. tuberculata still occurs in abundance. Radio telemetry was used to assess the foraging movements of female M. tuberculata while the composition of plant species visited by M. tuberculata was determined using phenological surveys in conjunction with weekly sampling of pollen from the fur of the bats. Special consideration was given to the association of M. tuberculata with the native wood rose (Dactylanthus taylorii). Results show that although the movement patterns of M. tuberculata are similar between Pureora and a previously studied population from the Eglington Valley in Fiordland, the individuals in this study ranged over considerably smaller areas. Bats’ space-use was influenced by the onset of flowering in D. taylorii. A pollen analogue experiment showed extensive within-patch movement of D. taylorii pollen, and to a lesser extent, directed dispersal of pollen between spatially isolated patches. Finally, the plants whose pollen M. tuberculata was found to carry have all been previously identified as potential food sources for lesser short-tailed bats. However, this study shows that two of these plant species may compete for the pollination services of M. tuberculata; evidence is provided of these plants adapting the timing of their flowering to reduce this competition. The findings of this study will build on the limited knowledge of the foraging behaviour and spatial ecology of M. tuberculata, both generally and in relation to the pollination services it provides.