Rapidly changing environments have serious consequences for native animal populations. Anthropogenic pressures brought on by human settlement often force large land mammals like the African elephant (Loxodonta africana) to adapt much quicker than natural evolution pace accommodates. Several factors have disrupted their daily and seasonal rhythms. The most severe effects stem from the loss of habitat combined with a warming world that has decreased vegetative nutritional access. Dr. Isabelle Szott led an international group of conservation biologists and endocrine researchers from South Africa and the UK to investigate how these human-caused effects may be detected using metabolic hormones, such as triiodothyronine (T3), without waiting for body condition and reproductive rates to deteriorate at the population level.
How Does The Thyroid Fit In?
Endocrine markers, such as thyroid hormones, provide significant conservation value for monitoring and quantifying the energetic state of the elephants and their caloric intake. Having a sufficient caloric intake directly affects the animals’ wellbeing and ability to reproduce. Thyroid hormones like T3 that control metabolism and appetite have been studied in captive populations for this reason. Managers of wild populations must clearly understand the correlation between hormone concentration and environmental factors in natural habitats for effective conservation efforts.
Samples and Their Part
To that end, the scientists collected 188 fecal samples from elephants at the Madikwe Game Reserve in South Africa. They extracted T3 from each sample and measured its concentration using Triiodothyronine (T3) ELISA Kits (K056-H) from Arbor Assays. Researchers also measured population, temperature, and food availability using the normalized difference vegetation index (NDVI). The researchers related increasing NDVI to higher T3 concentrations, showing that elephants consumed more food and expended more energy as expected with more vegetation available. However, that relationship disappeared as the environment’s temperature rose, indicating that the elephants reverted to a resting metabolic state during heat waves regardless of food availability. This could have serious implications on the native population’s health as climate change continues to create warmer conditions, disrupting their natural foraging and migration patterns that accommodate the seasonal variation in vegetation growth.
While the environmental implications are bleak, studies like this are vital in understanding the most effective strategies that wildlife conservation managers can use to keep elephant populations healthy, such as providing additional targeted water sources and forage for the animals in their region.