The urban ecology of bats in Singapore: understanding the human-wildlife interface

Urbanisation is a transformative land use change that has drastic ecological consequences worldwide, including biodiversity loss. There is more at stake in the tropics because these regions are global centres of biodiversity, yet very few studies of tropical wildlife in urban areas exist. Based in the urban tropics of Singapore, this thesis intends to fill a knowledge gap using acoustic approaches to sample biodiversity. I used acoustic recorders to quantify the impacts of major roads, the habitat value of green roofs, and the effects of large-scale transboundary smoke-haze pollution on biodiversity in Singapore. For the first two studies, bats were used as a focal taxon because of their ubiquity in the urban environment and their recommended roles as suitable indicators of the effects of urbanisation. Prior to these studies, acoustic guidelines for bat sampling were written and compiled. The third study involved soundscape recordings from a monitoring project, which coincided with one of the worst smoke-haze pollution events in Southeast Asia. The studies revealed that: i) Lighting on major roads had a negative impact on bat activity in both forest and urban habitats, and may present a barrier for forest-dependent bats, while some species utilised areas near to roads to some degree; ii) Green roofs supported substantial bat activity, especially on those that were newer, low, had higher shrub cover, higher night time temperature and a medium pruning regime, at the expense of pesticide use, and iii) Levels of acoustic activity dropped drastically during the peak of the pollution event and there was only partial recovery to pre-haze levels after 16 weeks. The outcomes from these three studies were informative for the design of mitigation and enhancement measures to support urban biodiversity, to identify future research directions using more process and mechanistic approaches to study the urban environment, and to explore avenues to involve citizens in biodiversity monitoring.