Rhino conservation in Kenya
Chester Zoo Conservation Scholar Nick Harvey from the University of Manchester is working with us to investigate the conservation physiology of the Eastern black rhino as part of his PhD. He tells us more about his project and what he hopes to achieve.
“Due to the first poaching crisis of the 1970s and 1980s, Kenya’s conservation strategy for the Eastern black rhino is focused on the creation and maintenance of specially fenced and protected areas called sanctuaries. From the mid-1980s, individuals from outside these areas, considered as non-viable populations, were translocated into them.
“This originally focused on four of these sanctuaries but more have been established since and their populations founded using rhinos from the original four. This led to a significant decrease in poaching and a growth in numbers from 380 in 1987 to 458 in 2003. There are now around 700 individuals in Kenya, spread across a range of national parks and reserves, on private conservancies, and on municipal and community land.
“Our partner, the Kenya Wildlife Service (KWS), has a long term vision of a ‘meta-population in Kenya of 2,000 Eastern African subspecies of black rhino managed in natural habitat in the long term.’ Currently, population performance varies between reserves with some of them missing the targets set by the International Union for Conservation of Nature (IUCN) and KWS.
“The breeding success of Eastern black rhinos at zoos has improved in recent years and this is in part due to the physiological research carried out at Chester Zoo by Conservation Scholar Alumni Katie Edwards. During her PhD, Katie measured the progesterone, testosterone and glucocorticoid content of faecal samples taken from rhinos. Her work has contributed a ‘baby boom’ in the zoo population. The aim of my work is to take similar techniques and apply them to the population in the wild with the aim of using the information gained to support those populations.
“During my fieldwork, I will take faecal samples from populations in different conservancies in Kenya and will measure a number of parameters in order to try and determine what the causes of the variation in breeding rates are. Glucocorticoids can give an indication of stress levels. Chronic stress, as indicated by abnormal glucocorticoid concentrations, leads to a diversion of resources away from reproduction potentially leading to a range of pathologies effects that reduce fitness by damaging reproductive function, survival or both. Chronically decreased thyroid hormones represent nutritional stress. It has been shown that average testosterone concentration is positively correlated with the number of offspring fathered per year spent in the reproductive age of black rhinos in zoos.
“Studying the testosterone, glucocorticoid and thyroid levels of wild males and correlating these results with habitat quality and other environmental factors will provide a valuable insight into the causes behind the variation in their breeding success. For females, I will analyse glucocorticoids and thyroid concentrations, which will allow me to determine whether variation in breeding success between individuals is caused by chronic stress and/or nutritional stress.
“In order to study the intra-population variation in breeding success, I am going to target three females and three males on each reserve, across a gradient of breeding success for each sex. This will allow me to compare glucocorticoids levels in both sexes and testosterone levels between high performing and low performing individuals across reserves.
“Faecal analysis can also be used to estimate diet quality for wild herbivores. Measurements can be carried out alongside hormonal studies to aid in attributing cause to incidences of poor population performance.
“Another factor that may negatively influence breeding success of individuals and therefore the growth of a population is helminth infection. Estimating the parasite load of individuals within a population can therefore be a conservation-relevant indicator of population health and could help in explaining sub-optimal performance. Faecal egg counts are often used as a non-invasive way of estimating parasite load in wild, threatened populations and so I will look at this too as part of my research.”
Nick Harvey is a student on the NERC-funded Earth, Atmosphere and Oceans doctoral training programme and is supervised by Dr Susanne Shultz, Dr Angela Harris, Dr Bradley Cain, Dr Cathy Walton and Dr Sue Walker and his research is supported by the Kenyan Wildlife Service. Nick will travel to Kenya to conduct his fieldwork soon so more updates on his PhD will follow.