Ecology, Environment and Conservation Paper

THE NEST DECAY RATES OF INFANT BORNEAN ORANGUTANS (PONGO PYGMAEUS WURMBII, TIEDEMANN 1808) AT NYARU MENTENG REINTRODUCTION CENTER IN PALANGKA RAYA INDONESIA

Fouad Fauzi, Soemarno, Aminudin Afandhi and Amin Setyo Leksono

Abstract

This research was conducted to analyze the decay time of the nests of infant Bornean orangutans at the Arboretum Nyaru Menteng Reintroduction Center, Palangka Raya, and Central Kalimantan. The 14 nest were observed from 8 infant orangutans. The observations on the nest were carried out until 72 days to see the color changes and determine the nest class. The environmental factors such as temperature and humidity were recorded daily. Nest material was identified to tree species. The average of decay time was 48 days or (mean ± SD = 48 ± 14 days) = 34 to 62 days. The longest decay of the nest was a night nest in the Shorea smithiana trees with 68 days resistance. The decay rate of the nest class was strongly influenced by the factors that were directly related to the making of a nest; the skill of a infant orangutan in making a nest, the strength of a branch or tree branch and the thickness of the leaves for making a nest and climatic factors such as temperature and humidity. Correlation test results between nest class with a temperature of 0.248 (weak correlation) and not significant (0.374> 0.025) as well as correlation between nest classes with humidity (-0.228). On the contrary there was a strong correlation between temperature and humidity but negative (-0.889), it means that the increase of temperature decreased the humidity.