Abstract
M.Sc. (Biodiversity and Conservation)
The relative activity levels of the Egyptian free-tailed bat (Tadarida aegyptiaca) and Cape
serotine bat (Neoromicia capensis) were monitored in eight study areas spanning across the
Eastern Cape, Western Cape and Northern Cape of South Africa. The detected activity levels
were then used to study the habitat use and temporal distribution (across the night and
months of monitoring period) of both species. The effect of weather conditions (namely
temperature, relative humidity, wind speed, precipitation and barometric pressure), moon
phase and moonlight on activity was also examined. The understanding of these aspects of
the ecology of N. capensis and T. aegyptiaca were then used as guidelines to conserve these
species with regards to wind farm development in South Africa.
Bat activity was monitored by means of a total of seventeen passive monitoring systems
consisting of SM2BAT+ bat detectors. The monitoring systems were deployed on the study
areas to detect and record bat echolocation calls on a continuous basis throughout the
night. Activity was recorded for a variable length of time, between 3 and 12 months, for
each study area. The bat detectors were powered by solar energy systems.
Habitat use by these species was analysed by comparing the activity amongst the different
study areas. Both species showed considerable activity in most study areas depicting them
to mostly be generalists inhabiting many habitats across the country. Bat activity amongst
the different land use types, vegetation types and climate regions was studied. N. capensis
showed significantly higher activity in a fruit farming area and T. aegyptiaca was significantly
less abundant in dry and arid conditions than cooler humid environments. The preference
for habitat based on altitude and height above the ground was assessed. The highest activity
occurred in coastal regions of 0 – 500 m altitude. N. capensis was found to prefer activity at
canopy height, and T. aegyptiaca is more of an opportunistic species making use of the most
profitable vertical airspace at any one time
Analysis of the hourly and monthly distribution of bat activity showed that it can be highly
variable across a range of temporal scales from all study areas. On a broad scale, N. capensis
was found to limit nightly activity within the first four hours of sunset, mostly peaking within
the second hour. T. aegyptiaca tends towards peak activity within the first three hours of
the evening, thereafter sustaining more or less constant activity until the ninth hour after
sunset. For both N. capensis and T. aegyptiaca, activity in the Eastern Cape is greater over
the months of September to March. Western Cape activity shows a general increase into the
warm months of September – December followed by a decrease over the hot months of
January and February. From the limited data set, activity in the Northern Cape seems to be
highest over the months of November, December and April...