The transformation of native habitats into forest plantations for industrial purposes
frequently has negative consequences for biodiversity. We evaluated the
impact of eucalypt plantations on native bats in a Mediterranean area, taking
Portugal as a case study. We compared the overall bat activity, species richness
and Kuhl’s bat Pipistrellus kuhlii (the most abundant bat species in the area)
activity between eucalypt plantations and native montado habitat, and examined
the influence of stand, landscape and survey variables within plantations on the
response variables. A set of 11 plantation stands, three landscape and two survey
variables were employed as predictor variables using a zero-inflated Poisson generalized
linear mixed model. Hawking and generalist bats of the genus Pipistrellus
were the most frequently detected species. Bat activity, species richness and
P. kuhlii activity were higher in native montado than in any of the eucalypt stands.
Mature eucalypt plantations showed the highest bat activity, while clear-cut areas
showed the lowest. Generally, within eucalypt stands, complex high-level vegetation
structure, from the ground level up to 3 m high, and proximity to water points
were associated with higher levels of bat and P. kuhlii activity and species richness.
The results suggest that in order to promote bat diversity and activity in exotic
eucalypt plantations in the Mediterranean region, it is important to provide a high
density of water points, maintain plots of mature plantations and promote
understorey clutter.