Thermoregulation in Homopus signatus
Relatively low environmental temperatures in winter and spring, when food is available in the Namaqualand winter rainfall region, appear to require considerable basking time for Homopus signatus to elevate body temperatures to levels that can support activity and metabolism. This basking time is not available for other activities. Currently, several factors might facilitate the species spend a significant amount of its time budget basking. However, anthropogenic impacts, including climate change, may alter these factors and consequently behavioural time budgets and body temperatures. The aim of this study was to determine if low environmental temperatures are challenging H. signatus at times when food is available, indicating its potential vulnerability for anthropogenic impact.
Materials and methods
We used radiotelemetry, iButtons, and tortoise models.
Timeframe and status
The study started in 2012, and would finalise in 2014. However, it was extended to 2015 as a result of low tortoise activity in 2014. The data processing and publishing started in 2014 and ended in 2017.
Homopus signatus basking to elevate its body temperature.
Two students from the Van Hall-Larenstein University of Applied Sciences (Netherlands) have measured individual time budgets. The study was a collaboration with the Chelonian Biodiversity and Conservation programme of the University of the Western Cape, and the Northern Cape Department of Environment and Nature Conservation (South Africa).
Total budget was circa € 22,000. This amount included resources that were invested by fieldwork volunteers and students, and did not contain salary: all participants in the Homopus Research Foundation work as volunteers and do not receive salary.