Effects of Forest Type and Human Presence on Bonobo (Pan paniscus) Density in the Salonga National Park1

Abstract

Our study elucidates how forest type characteristics and human presence influence bonobo (Pan paniscus) densities and assesses whether the SalongaNational Park harbors a substantial bonobo population. We searched 11 locations in the Salonga for the presence of bonobos and sampled 9 study sites using line transects to estimate relative bonobo nest density, the proportion of forest types, and the intensity of human activity. We classified forests into broad types by overstory and understory composition, canopy cover, and hydrology, and calculated encounter rates for bonobo, human, and large mammal signs. Bonobo signs occurred in 8 of 11 locations but varied widely in frequency. Mean density was 0.72 nest-builders/km 2 , but density was not uniform across sites (range = 0-2.8 nest-builders/km 2 ). Of 11 forest types encountered, the most common were mixed mature forest with an herbaceous (Marantaceae) understory (36.8%), with a woody understory (23.6%), and old secondary forest with a Marantaceae understory (10.5%). Nest sites occurred only in these forest types, called nest-forest types. Bonobo density was highest in locations comprising >80% nest-forest types. Nests 1 We dedicate this paper in humble gratitude to the Sandra and Fred Young family in recognition of their exceptional interest and generous support to ensure that bonobos survive in their homeland. 603 0164-0291/06/0400-0603/0 C 2006 Springer Science+Business Media, Inc. 604 Reinartz et al. occurred more frequently in the mixed mature/Marantaceae forest. Nest-site density correlates positively with the nest-forest patch length we encountered on transects, implying that forest patch size and consistency may influence bonobo density. Mean nest group size correlates positively with proportion of nest-forest types found at a site, suggesting that increased resource availability-nesting sites and food-allows larger group size. A significant inverse association existed between bonobo density and human presence.

The Golden-bellied Mangabey Cercocebus chrysogaster (Primates: Cercopithecidae): distribution and conservation status

“…1) were: (1) across the 24,000 km 2 landscape defined at the southern limit by the Sankuru River and going north to include twenty percent of the SNP comprised by the watershed of the Lokoro River systems during the period intermittently between 1994(Thompson unpub. data, 1997, 2002, (2) the region between the Lokoro River to the Salonga-Looto River during the period -2002(Inogwabini & Omari 2005Reinartz et al 2006) within the SNP, and (3) the region between the Kwa-Kasai and Lulonga rivers, west of lake Maindombe, including the area between the Lulonga River and Congo River, the swamps of Ngiri River, the forest between the Ngiri and Ubangi rivers, and the forest around and adjacent to Lake Tumba; limited in the north by a straight line from Mobeka parallel to the equator joining the Ubangi River during the period [2005][2006][2007]. All three surveys combined three methods: (1) straight line transects with variable lengths (Buckland et al 1993;Hall et al 1997), (2) comprehensive or guided reconnaissance (Walsh et al 2001;Blake 2002), and (3) forest exploration, known as reconnaissance (Hall et al 1997;Van Krunkelsven et al 2000;White & Edwards 2002).…”

Habitat use of bonobos (Pan paniscus) at Wamba: Selection of vegetation types for ranging, feeding, and night‐sleeping

“…Sympatric chimpanzees preferred using small patches of primary forest that provided more fruit than other forest types throughout the year of study, and also preferred using secondary forest when figs were in season in the forest type [Basabose, 2005]. Because detecting food distribution over a wide area is difficult without exhaustive ground-based vegetation surveys, classifying forest habitats by certain general characteristics, such as succession level and types of understory (such as Marantaceae or woody), is one way to measure resource availability [Reinartz et al, 2006]. If it is possible to differentiate habitat selection by forest type, one may extrapolate the selection pattern to a wider area through the use of spatial modeling using GIS and remotely sensed data.…”

Spatiotemporal Variation in Bonobo (Pan paniscus) Habitat Use in a Forest–Savanna Mosaic

“…In future studies, we need to independently assess human activities in this region to evaluate the direct influence of human proximity on bonobo spatial distribution at this site on the periphery of the bonobo home range. Previous studies demonstrate clear negative relationships between human presence and bonobo presence (Hickey et al 2013;Reinartz et al 2006). However, relatively high bonobo densities occur near villages for which eating bonobos is a taboo (Thompson et al 2008), showing the need to consider the sociocultural context to assess the influence of humans on bonobo distribution, as shown for other primate species (Estrada et al 2006;Riley and Fuentes 2011;Setchell et al 2017;Strindberg et al 2018).…”

“…However, other studies in bonobos have found no effect of fruit availability on THV consumption (Malenky and Wrangham 1994;White and Wrangham 1988). Finally, bonobos have been described as nesting mostly in mixed terra firma forest, also called primary forest or dry forest, with a predominance of mixed forest with Marantaceae understory (Hashimoto et al 1998;Idani et al 1994;Kano 1992;Reinartz et al 2006;Terada et al 2015).…”