Model of population management for javan rhinoceros (Rhinoceros sondaicus) based on analysis of nutrition and stress levels as health parameters

Abstract

This research was designed to establish a model for population management for javan rhinoceros (Rhinoceros sondaicus), a critically endangered species inhabiting Ujung Kulon National Park. Population increase by 3% every year had been assigned by the Ministry of forestry and this rate of population increase heavily relied on the ability of this species to survive and to reproduce naturally. The habitat of the rhino has conditions that were not always favourable to the rhinos and these conditions could potentially trigger stress for these animals. The research was divided into three stages consisting of analysis of nutritions and digestibility profiles of three male rhinoceros, analysis of relationship between stress levels on hormone profile of these animals, and stress induction to model animals. Two horses were selected as models for stress on rhinoceros, as the stress induction could not be done on the rhinoceros directly due to their small numbers worldwide; thus designated as a criticaly endangered species. The results of this research showed that the feed profile directly correlated with the home range and the vegetation structure around each individual rhinoceros and there were indications that the rhinos experienced feed deficit in quantity and quality. Analysis using 3α, 11β-dihydroxy-CM as an indicator of glucocorticoid stress hormon levels suggested that the rhinos experienced greater stress during the dry season when the water source was significantly depleted. This fact was also consistent with the result from stress induction on horse as model animal suggesting that feed deficit created acute type stress while water deficit created a chronic type stress. Compilations of the results from the research stages were formulated into a model of population management for javan rhinoceros with recommendations such as: habitat enrichment using feed plants high in protein (Moringa citrifolia, Callicarpa longifolia, Chisocheton microcarphus), high in fat (Alstonia angustiloba, Callicarpa longifolia, Macaranga spp), high in energy (Derris thyorsifolia, Pterospermum javanicum, Percampyulus glances) with density of 15 per hectare (tree form) to 5,406 per hectare (seedling form); water availability can be enhanced by replenishing feed plants high in water contents such as: Paederia scandens, Alstonia scholaris, Costus speciosus, as well as maintaining access and trais to water sources that were available year round. The use of 3α, 11β- dihydroxy-CM needs to be validated using biological and chemical measures to investigate its potential use in monitoring stress levels of javan rhinos in the wild; horse can be used as relevant model animal for research in stress and its implications to the javan rhinoceros.