MICROCLIMATIC CONDITIONS IN MATERNITY CAVES OF THE BENT-WING BAT, MINIOPTERUS-SCHREIBERSII - AN ATTEMPTED RESTORATION OF A FORMER MATERNITYSITE

A 2-year study of Bat and Robertson caves in south-eastern South Austr alia provided information on the microlimatic conditions in a maternit y cave of the bat Miniopterus schreibersii. The study also monitored c hanges in the temperature and humidity conditions in what is believed to be a former maternity site, Robertson Cave, following restoration o f the damaged done. The maternity cave, Bat Cave, was characterised by mild hypoxic and hypercapnic conditions, high relative humidity, and temperatures in the roosting area of around 30-degrees-C. Accumulated guano deposits had some areas of heat generation, but the bats themsel ves appeared to be the primary modifiers of their own microenvironment . To support this finding, the recapping of Robertson Cave resulted in high humidities and a narrow range of temperature fluctuations; howev er, the temperature never reached the levels seen in Bat Cave. Our con clusion that the heat production of the bats themselves is the prime f actor affecting microclimatic conditions necessary for breeding may re late to the observation that few maternity sites serve large and wides pread populations of this species.