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Title: Seed Dispersal Effectiveness in Two Populations of Bornean Orangutans (Pongo pygmaeus wurmbii)
Orangutans consume large quantities of ripe fruit and disperse intact seeds over wide areas. However, few studies have quantified seed dispersal in orangutans (Galdikas 1982; Nielsen et al. 2012). We hypothesized that orangutans are effective seed dispersers. This was tested by identifying, measuring and counting seeds in orangutan feces and recording fecal coordinates to determine seed spatial distribution patterns. Orangutan feces were collected opportunistically from March- September 2015 at the Tuanan Research Station (n=97) and from July- August 2016 at the Cabang Panti Research Station in Gunung Palung National Park, Indonesia (n=98). The feces were sieved, seeds were counted, and seed morphotypes were identified in at least 96% of fecal samples. Flanged males, unflanged males, adult females, and juveniles independent enough from their mother to allow for fecal collection, were all observed dispersing seeds. Four fruit genera were dispersed at Cabang Panti and nine fruit genera were dispersed at Tuanan. At Cabang Panti, the largest intact seed size recorded was 2.29cm in length and the smallest seeds dispersed were less than 1mm Ficus seeds. At Tuanan, 31% of fecal samples had 2 or more genera, 42% had 1 genera, and 26% had no seeds. We used descriptive GIS to describe the spatial distribution of the dispersed seeds. We concluded that orangutans have an important role in fruit tree recruitment. They disperse intact seeds of varying sizes and disperse several different genera of seeds. Future research will measure seed dispersal distances and orangutan gut-passage rates to establish the orangutan seed shadow. Funders include the National Geographic Society, the Leakey Foundation, the US Fish and Wildlife Service, United States Agency for International Development, and the National Science Foundation (BCS-0936199).  more » « less
Award ID(s):
0936199
PAR ID:
10039655
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
American journal of physical anthropology
Volume:
162
Issue:
S64
ISSN:
0002-9483
Page Range / eLocation ID:
122
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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