Oral Presentation- Symposium 12th International Mammalogical Congress

Habitat islands in the sky: Bat use of green roofs in a tropical city (#372)

Benjamin PYH Lee 1 2 , Zoe G Davies 2 , Matthew J Struebig 2
  1. National Parks Board, Singapore
  2. Durrell Institute of Conservation & Ecology, University of Kent, Canterbury, Kent, United Kingdom

Green roofs, which are building rooftops with a growing substrate and vegetation, have great potential for urban biodiversity conservation, apart from providing other ecosystem services such as reduction in storm-water runoff. We investigated the habitat value of intensive green roofs for bats in highly urbanised Singapore using an acoustic approach. Bat activity (as measured by bat passes) was monitored using stationary bat detectors for seven nights each over 24 green roofs, which were stratified into ‘low’ (≤ 24 m) and ‘high’ roofs (> 24 m). Roof characteristics, management regimes and surrounding land cover metrics were investigated as possible predictors of bat activity using generalised linear mixed models (GLMMs). Four bat species (Scotophilus kuhlii, Saccolaimus saccolaimus, Taphozous melanopogon and Myotis muricola) were recorded. The most common species was S. kuhlii, which accounted for 80.3% of all bat passes, and the mean number of bat passes recorded per night was 30.6, pooled across all four species. Planted roof area was not a predictor of bat activity but the age and height of roofs had a strong negative influence. Bats responded positively to structural features of the roof vegetation. Green roof maintenance operations such as pruning and pesticide application had positive and negative effects respectively on bat activity. Finally, at a landscape scale, there was some evidence that the lack of vegetation in the immediate area of the roof (125 m buffer) negatively affected bat activity. Some recommendations are made to improve green roofs as habitats for tropical bats.