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1. Quantity and Quality of Orangutan Seed Dispersal in Gunung Palung National Park, Borneo, Indonesia

   Blackburn, Andrea; Rizal, Ahmad; Susanto, Tri Wahyu; Knott, Cheryl D (November 2019, Northeastern Evolutionary Primatologists Meeting 2019)

   Orangutans are large-bodied frugivores predicted to be effective seed dispersers. We studied Bornean orangutan (Pongo pygmaeus wurmbii) seed dispersal effectiveness, by measuring the quantity of seeds dispersed and the quality of dispersal in Gunung Palung National Park, Borneo, Indonesia (August 2018 to August 2019). For dispersal quality we conducted germination experiments, measured germination rates, and modeled dispersal distances. We systematically collected orangutan fecal samples, feeding behavior, and GPS tracks during focal follows. We sieved 549 fecal samples collected from 36 orangutans and identified the seeds, and of the fecal samples collected 75.2% contained seeds. A total of 24 genera were dispersed via endozoochory. Germination experiments were conducted with orangutan defecated seeds and seeds from fruits. A significantly higher percent of orangutan defecated seeds germinated for 5 out of 6 genera than control seeds with pulp (p<0.01). A significantly higher percent of orangutan defecated seeds germinated for 3 out of 6 genera compared to control seeds without pulp (p<0.01). Gut transit times in wild orangutans ranged from 39.5 to 87 hours. Finally, we modeled seed dispersal distances using orangutan movement tracks (n= 30) with gut passage durations of 45 and 60 hours. Gut retention times of 45 hours resulted in a mean dispersal distance of 507 ± 123m, and 60 hours resulted in a mean distances of 592 ± 115m. We conclude orangutans are effective seed dispersers, as orangutans disperse a wide variety of genera over medium to long distances and defecated seeds exhibit high germinability. Orangutans are large-bodied frugivores predicted to be effective seed dispersers. We studied Bornean orangutan (Pongo pygmaeus wurmbii) seed dispersal effectiveness, by measuring the quantity of seeds dispersed and the quality of dispersal in Gunung Palung National Park, Borneo, Indonesia (August 2018 to August 2019). For dispersal quality we conducted germination experiments, measured germination rates, and modeled dispersal distances. We systematically collected orangutan fecal samples, feeding behavior, and GPS tracks during focal follows. We sieved 549 fecal samples collected from 36 orangutans and identified the seeds, and of the fecal samples collected 75.2% contained seeds. A total of 24 genera were dispersed via endozoochory. Germination experiments were conducted with orangutan defecated seeds and seeds from fruits. A significantly higher percent of orangutan defecated seeds germinated for 5 out of 6 genera than control seeds with pulp (p<0.01). A significantly higher percent of orangutan defecated seeds germinated for 3 out of 6 genera compared to control seeds without pulp (p<0.01). Gut transit times in wild orangutans ranged from 39.5 to 87 hours. Finally, we modeled seed dispersal distances using orangutan movement tracks (n= 30) with gut passage durations of 45 and 60 hours. Gut retention times of 45 hours resulted in a mean dispersal distance of 507 ± 123m, and 60 hours resulted in a mean distances of 592 ± 115m. We conclude orangutans are effective seed dispersers, as orangutans disperse a wide variety of genera over medium to long distances and defecated seeds exhibit high germinability. Funders: National Science Foundation (BCS-1638823); National Geographic Society; US Fish and Wildlife Services (F19AP00798; F18AP00898); Disney Wildlife Conservation Fund 

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2. Fecal isotopes as indicators of weaning and diet in wild Bornean orangutans

   Knott, Cheryl D; Crowley, Brooke; Kane, Erin; Brown, Michelle; Susanto, Tri Wahyu (March 2019, American journal of physical anthropology)

   Orangutans have a 7.6 year average inter-birth interval, the longest of any mammal. Suckling occurs throughout that interval, until the birth of the next offspring, but it is unclear how important milk consumption is during that period, as we cannot assess the actual intake amount. Measurement of stable carbon isotope ratios (d13C), stable nitrogen isotope ratios (d15N) and nitrogen content of feces (%N) provide evidence of the transition between breast milk to solid food. Here we present pilot data on these isotopic ratios from matched fecal samples of mothers and offspring (n=43), collected from wild orangutans in Gunung Palung National Park, Borneo, Indonesia. We found that the youngest infant (2.3 yrs) had the highest d15N values overall, indicative of a higher percentage of animal products (milk) in the diet. Older juveniles (5.8 yrs) did not consistently show higher d15N than their mothers. This may indicate variation in suckling frequency or the amount of breast milk consumed per suckling session. Adolescents (10-13 yrs) showed significantly (GLMM, p< 0.007) lower d15N than samples taken from the same day on their mothers. This is surprising given that they were eating similar diets. We thus compare the isotopic signature of the plants consumed to examine the sources of this variation. We conclude that analysis of fecal samples collected from wild orangutans can be used to assess the relative importance of breast milk in the diet, but caution that isotopic excretion may also be effected by differences in the isotopic content of the diet. Funders: NSF (BCS-1638823, BCS-0936199); National Geographic; USFish/Wildlife (F15AP00812, F13AP00920, 96200-0-G249, 96200-9-G110); Leakey; Disney Wildlife Conservation; Wenner-Gren; Nacey-Maggioncalda; Orangutan Conservancy; Conservation-Food-Health; Woodland Park Zoo; Holloman Price; AZA; Ocean Park Conservation; USAID; Arcus 

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3. Orangutan Seed Dispersal in Gunung Palung National Park, Borneo, Indonesia: Dispersal Quantity, Germination Rates, Gut Transit Times, and Dispersal Distances

   Blackburn, Andrea; Susanto, Tri Wahyu; Knott, Cheryl D (March 2020, 7th Frugivores And Seed Dispersal Symposium 2020)

   Orangutans are large-bodied frugivores predicted to be important seed dispersers, however little is known about their seed dispersal effectiveness. To understand wild Bornean orangutan (Pongo pygmaeus wurmbii) seed dispersal effectiveness, we measured the quantity of seeds dispersed, and we considered the quality of dispersal by measuring germination rates of gut-passed and control seeds, gut transit times, and dispersal distances. Research was conducted in Gunung Palung National Park, Borneo, Indonesia (August 2018 to August 2019). We systematically collected orangutan fecal samples, feeding behavior, and GPS tracks during consecutive full-day focal follows. We sieved 549 fecal samples collected from 36 orangutans to count and identify seeds (>2mm). Out of the fecal samples collected, 413 (75.2%) contained seeds. A total of 24 genera were dispersed via endozoochory. Orangutan fecal samples contained a mean of 1.17 genera (range 0-7). Germination experiments were conducted with orangutan defecated seeds and seeds from fruit. A significantly higher percent of orangutan defecated seeds germinated for 5 out of 6 genera than control seeds with pulp (p<0.01). A significantly higher percent of orangutan defecated seeds germinated for 3 out of 6 genera compared to control seeds without pulp (p<0.01). Gut transit times in wild orangutans ranged from 39.5 to 87 hours (n=6). Finally, we modeled seed dispersal distances using orangutan movement tracks (n= 30) with gut passage durations of 45 and 60 hours. Gut retention times of 45 hours resulted in a mean dispersal distance of 507 ± 123m (range 69 - 1341), and 60 hours resulted in a mean distance of 592 ± 115m (range 83 - 1260). We conclude orangutans are effective seed dispersers with similar efficacy to other great apes. Orangutans disperse a wide variety of genera over medium to long distances and gut passed seeds germinate at higher rates compared with controls. Keywords: Ecology, Seed dispersal effectiveness, Movement, Tropical, Asia Funders: National Science Foundation (BCS-1638823); National Geographic Society; US Fish and Wildlife Services (F19AP00798; F18AP00898); Disney Wildlife Conservation Fund 

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4. Diet alters rodent fecal pellet size: implications for paleoecological and demographic studies using fecal dimensions

   https://doi.org/10.1093/jmammal/gyab098  

   Maurer, Maya; Peralta Martínez, Karen; Trevelline, Brian K.; Tripoli, Domenique; Dearing, M. Denise; Derting, Terry; Martinez Mota, Rodolfo; Pasch, Bret; Kohl, Kevin D.; Zollner, ed., Patrick (September 2021, Journal of Mammalogy)

   Abstract Measurements of fecal pellet size can provide important information about wild mammals, such as body size and demographic information. Previous studies have not rigorously tested whether diet can confound these measurements. Furthermore, it is unknown whether diet might alter fecal dimensions directly or through changes in animal physiology. Here, we studied three closely related rodent species that differ in natural feeding strategies. Individuals were fed diets that varied in protein and fiber content for 5 weeks. We then measured body size, fecal widths and lengths, and the radius of the large intestine. Diet composition significantly changed fecal widths in all species. High-fiber content significantly increased fecal widths and would cause overestimations of body size if applied to wild feces. Using path analysis, we found that fiber can increase fecal widths both directly and indirectly through increasing the large intestine radius. Protein affected each species differently, suggesting that protein effects vary by species feeding strategy and existing physiology. Overall, diet and large intestine morphology can alter fecal pellet measurements. Studies using fecal measurements therefore must consider these effects in their conclusions. 

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5. Mule deer do more with less: comparing their nutritional requirements and tolerances with white-tailed deer

   https://doi.org/10.1093/jmammal/gyab116  

   Staudenmaier, Anna R.; Shipley, Lisa A.; Camp, Meghan J.; Forbey, Jennifer S.; Hagerman, Ann E.; Brandt, Abigail E.; Thornton, Daniel H.; Moore, ed., Ben (November 2021, Journal of Mammalogy)

   Abstract Congeneric species often share ecological niche space resulting in competitive interactions that either limit co-occurrence or lead to niche partitioning. Differences in fundamental nutritional niches mediated through character displacement or isolation during evolution are potential mechanisms that could explain overlapping distribution patterns of congenerics. We directly compared nutritional requirements and tolerances that influence the fundamental niche of mule (Odocoileus hemionus) and white-tailed deer (O. virginianus), which occur in allopatry and sympatry in similar realized ecological niches across their ranges in North America. Digestible energy and protein requirements and tolerances for plant fiber and plant secondary metabolites (PSMs) of both deer species were quantified using in vivo digestion and intake tolerance trials with six diets ranging in content of fiber, protein, and PSMs using tractable deer raised under identical conditions in captivity. We found that compared with white-tailed deer, mule deer required 54% less digestible protein and 21% less digestible energy intake per day to maintain body mass and nitrogen balance. In addition, they had higher fiber, energy, and dry matter digestibility and produced glucuronic acid (a byproduct of PSM detoxification) at a slower rate when consuming the monoterpene α-pinene. The mule deers’ enhanced physiological abilities to cope with low-quality, chemically defended forages relative to white-tailed deer might minimize potential competitive interactions in shared landscapes and provide a modest advantage to mule deer in habitats dominated by low-quality forages. 

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