Estimating population dynamics (the number, gender, age and relatedness of individuals in a population) and viability (reproductive ability, adaptability) is essential to understanding the degree of security or threat facing a species. However, many methods of analysing these factors intrinsically change the value of the data. For example, anesthetising free-ranging animals repeatedly to take blood and tissue samples to determine reproductive and health status can cause so much stress that reproduction is inhibited, health is affected and may change the population’s behaviour towards that individual.
Zoo-based populations give us a unique opportunity to assess individuals that are accustomed to human contact, increasing confidence in the baseline data collected. Perhaps more importantly, having detailed knowledge of the Zoo-based population allows us to develop techniques for assessing population parameters non-invasively. For example, we now know that faecal and urine samples from an individual mirror hormone levels in the blood, with some delay. The Wildlife Reproductive Centre (WRC)based at the Taronga Western Plains Zoo can now collect information about the reproductive cycles of females, seasonality, diagnose pregnancy and predict when birth will occur in many species without even coming close to the animal. We can also assess levels of adrenal hormones (which indicate stress), take genetic samples and tell a great deal about diet and general health from these same “remote” samples.
Reproductive and adrenal hormones are metabolised to smaller fractions and excreted in the urine and faeces. The type of hormone fractions (called metabolites) and the way they are excreted (in urine or faeces) may differ from species to species. Specific techniques have been developed and validated for each species of interest, so that hormone concentrations can be assessed non-invasively. These techniques can be used to evaluate hormones from captive and wild animals, and combined with behavioural observations they increase our understanding of the biology of each species.
The Wildlife Reproductive Centre at Taronga Western Plains Zoo was the first of its kind in Australia when it was built in 1994. The WRC works with other staff within the Taronga Conservation Society Australia, other wildlife organisations or academic collaborators to gain information needed for the management of captive or free-ranging populations and to answer fundamental questions about reproductive biology and population dynamics and viability.
The WRC also incorporates the Animal Gene Storage Resource Centre of Australia (AGSRCA) which was established as a joint venture between the Taronga Conservation Society Australia and the Monash Institute of Reproduction and Development in 1995, and includes “frozen zoos” of genetic material at both sites. This program aims to develop new techniques to collect, preserve and store genetic material from endangered and other important species including the Black Rhinoceros, Greater Bilby, Common Wombat, Tasmanian Devil and African Wild Dog.