Distribution and preference of landscape features and foraging sites of insectivorous bats in Hong Kong urban parks

Abstract

Hong Kong is a densely populated city of seven million people; fast urbanization has removed or isolated lot of green area into fragments with a matrix of buildings. However, urban green area such as urban park may act as refuges for bats to use within urban environment. Since 2002, the Agriculture, Fisheries and Conservation Department (AFCD) has conducted a long-term baseline ecological survey on bat species. However, there still is an information gap of insectivorous bat in Hong Kong urban area due to some technical limitations. To fill this gap, this study conducted active acoustic surveys in urban parks. Besides, in order to have a better understanding on insectivorous bats in urban parks, investigation was carried out so as to examine how landscape features of urban park influence insectivorous bats and their preference of foraging sites. Forty-eight systematic bat acoustic surveys were conducted in 24 urban parks during autumn 2015 and spring 2016. A total of 13 insectivorous bat species were recorded. With updated distribution map of them, local status of Hypsugo pulveratus and Pipistrellus tenuis should be considered as a common or very common species. The result also showed different bats species preferred different foraging sites; two landscape features of urban park, green area (p<0.05) and water surface area (p<0.05) significantly contributed to the abundance of insectivorous bat in urban parks. Therefore, park managers should avoid excessive and unnecessary pruning and topping, frequent drying of water bodies. Since the sudden reduction of foraging sites and source of insects may have a critical influence on bat abundance.