Population viability analysis of the Philippine tarsier (Tarsius syrichta) in Corella, Bohol

• Main Authors: Arboleda, Irene Neri, Possingham, Hugh, Stott, Philip, Ball, Stephen
• Format: text
• Published: Animo Repository 2003
• Subjects: Tarsiers > Philippines > Bohol; Biology
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/11930
• Institution: De La Salle University

With the computer program ALEX we ran a series of simulations of the Philippine tarsier (Tarsius syrichta) wild population in Corella, Bohol, southeastern central Philippines. The use of plausible assumptions in the model indicated that, in the absence of any environmental catastrophe, a minimum viable habitat area of 60 has can support a population of 24 female tarsiers. Sensitivity analysis showed that the model's output was influenced by the values used for newborn, juvenile and adult mortality, but the effect of variation on adult mortality was more pronounced. The model showed that with regards to the newborn and juvenile mortality rate, if a sufficient high enough number (40 or more in a single patch) of female tarsiers are maintained, the effect on probability of extinction by slight variation on their rates can be reduced to a nearly negligible value. Adult mortality rate greatly influences the probability of extinction of the species. Measures should therefore be taken to reduce mortality in wild populations such as strict reinforcement on the ban for hunting, control of predator (cat) population and maintaining a large enough area so that variations in mortality will have reduced impact on population stability. Results in the introduction of catastrophe and variation in patch parameters, showed that tarsiers would have a better viability in several smaller and suitable patches maintained across its known distribution range rather than in just a few large patches of in just one big patch. An approach involving reconstructing or rehabilitating several degraded habitats across the known geographical distribution of T. syrichta must also be considered.