The diversity of plant species in the proboscis monkey’s habitat as a species reference for habitat restoration

Abstract

Most of the Proboscis monkey (Nasalis larvatus) habitat is outside the protected area, so the potential for destruction is high. One of the efforts to improve its habitat is habitat restoration. This study aims to determine plant species for proboscis monkey habitat restoration based on reference habitats. The research was conducted at eight locations in East Kalimantan, Indonesia i.e. Kuala Samboja, Mahakam Delta, Suwi River, Ohong River, Berau Delta (mangrove and riverine), Sungai Wain, and Kutai National Park. Vegetation analysis with line-plot sampling method with a total sample of all locations of 11.7 ha. The results showed that the habitat included three main types: mangrove, riverine, and riverine-near coastal. A total of 152 tree species, 41 of which were potential proboscis monkey feed. The highest plant species diversity value was in the riverine forest-Berau Delta of 1.25, while the lowest was in the mangrove forest-Berau Delta of 0.54. Species that are a food source and have good adaptation in riverine habitat are Vitex pinnata, Dillenia excelsa, Garcinia spp, Heritiera littoralis, Ilex cymosa, Cerbera manghas, Hevea braziliensis, and Sonneratia caseolaris. Whereas in mangrove habitat are Avicennia alba, A. officinalis, Bruguiera gymnorrhiza, B. parvifolia, Rhizophora apiculata, and S. alba. They are recommended for habitat restoration.

Camptostemon philippinensis, a new record of endangered mangrove species in the Balikpapan Bay, East Kalimantan, Indonesia

“…This discovery is assumed to be proboscis monkey bite marks, given that leaves are the primate's primary food source (folivorous) (Boonratana, 1993). Other mangrove species on Balikpapan Bay reported to have a high preference as a food source for proboscis monkeys are R. apiculata (Tangah & Bernard, 2010), S. alba, and S. caseolaris (Atmoko, 2022).…”

“…On the other hand, mangrove vegetation has a strong interaction with the presence of proboscis monkeys because the monkeys like young leaves, seeds, and mangrove fruit as food sources (Boonratana, 1993). Atmoko (2022) has reported as many as 41 plant species as food sources for proboscis monkeys from several habitats in East Kalimantan. In addition, proboscis monkeys often choose large mangrove trees on the banks of rivers or seas as sleeping trees to avoid predators.…”

Habitat use of proboscis monkey (Nasalis larvatus) in production forests of West Kalimantan, Indonesia

“…For example, Wakushima et al (1994) showed that S. alba grows in soil with high salinity and high pH and B. gymnorrhiza in soil exhibiting varying pH levels. S. alba has been reported to be a high preference plant for proboscis monkey food resource selection (Atmoko et al 2022). However, additional research in the future is required to understand the specific correlation of pH on resource selection of the proboscis monkey.…”