Animal-mediated seed dispersal is important for promoting forest regeneration and sustainability. Animal movement influences the distribution of seeds across the environment, resulting in spatially aggregated seed dispersal patterns. Animal seed dispersal patterns likely play an important role in the spatial structuring of tree populations: where a seed disperser moves influences the seed distribution. Environmental parameters that shape a disperser’s movement also influence the spatial distribution pattern of their seed dispersal. Orangutans are highly frugivorous and have been shown to disperse intact viable seeds. GPS locations were recorded for all orangutan defecations (n=1721) from 2014 to 2016 at the Cabang Panti Research Station in Gunung Palung National Park (GPNP), Indonesia. Our pilot research at GPNP measured seeds in fecal samples (n=98 fecal samples) and demonstrated that orangutan fecal samples do have intact seeds in more than 95% of t heir feces. A kernel density map was made using the defecation data to calculate the spatial density distribution of the defecations. A geographically weighted regression model (GWR) analyzed how well spatial parameters (altitude, slope, distance to river, and normalized difference vegetation index) predict the spatial density distribution of orangutan seed dispersal. All parameters in the GWR were statistically significant (R2=0.80, p<0.001) and showed low values for collinearity. The results show that orangutan seed dispersal is aggregated in space and the seed dispersal pattern is significantly shaped by environmental variables. This study provides us a better understanding of how the environment plays a role in determining animal behavior which influences the seed spatial distribution.
Funders include the National Science Foundation (BCS-1638823), National Geographic Society, US Fish and Wildlife (F15AP00812), Leakey Foundation, Disney Wildlife Conservation Fund, and Nacey-Maggioncalda Foundation.
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Moving through ecology: orangutan positional behavior in a mosaic habitat
Documenting the ways in which organisms physically move through space and the influences of habitat structure on their movement and posture are fundamental to understanding their spatial ecology. Movement ecology is thus a significant influence on animal cognition, morphology, diet, group structure, etc. Evidence to date demonstrates that orangutans of different species (Pongo abelii, P. wurmbii) living in similar habitats exhibit positional behavior more similar to each other than to conspecifics in disparate habitats. Therefore, it is a reasonable hypothesis that orangutan positional behavior is a function of habitat rather than morphological constraints. Here, we test this hypothesis by examining the positional behavior of orangutans living in Gunung Palung National Park in West Kalimantan, Indonesia, a primary forest mosaic composed of seven distinct habitats. We use 33,358 instantaneous scan samples collected every 5 minutes during full day follows of habituated adult orangutans (N=27) to examine postural behavior, locomotor modes, and structure use with a null hypothesis of no differences in positional behavior or support use profiles between habitats. We found significant differences in the profiles of orangutan postural behavior (G=216.2, p<0.001), locomotor behavior (G=45.34, p<0.001), and support use (G=137.8, p<0.001) in 5 distinct habitats within Gunung Palung National Park. Orangutans within the same population move through and use distinct habitats in different ways. This underscores the role of local ecology in structuring organisms’ space use as well as the importance of behavioral plasticity to primates’ movement ecology.
Funding: National Science Foundation (BCS-1638823, BCS-0936199); National Geographic Society; US Fish and Wildlife (F15AP00812, F12AP00369, 98210-8-G661); Leakey Foundation; Disney Wildlife Conservation Fund; Wenner-Gren Foundation; Nacey-Maggioncalda Foundation
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- NSF-PAR ID:
- 10110990
- Date Published:
- Journal Name:
- American journal of physical anthropology
- Volume:
- 168
- Issue:
- S68
- ISSN:
- 0002-9483
- Page Range / eLocation ID:
- 119
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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