Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces

Blumenthal, Scott A.; Chritz, Kendra L.; Rothman, Jessica M.; Cerling, Thure E.

doi:10.1073/pnas.1215782109

Cited by 49 publications

(93 citation statements)

References 76 publications

(105 reference statements)

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“…that were probable seed dispersers, and also inferred to have had a significant dietary component of leaves, were assigned to a mixed fruit-and-leaves dietary category (Dataset S1). If an organism's diet contains low levels of C4 vegetation, it can be difficult to distinguish between folivory and frugivory using stable isotope analyses because C3 plants often exhibit high isotopic variability (20); a mixed fruit-and-leaves diet category provides a conservative assignment for potentially ambiguous diets. We simulated the evolutionary history of diet using stochastic character mapping, a method for inferring discrete character changes that accommodates phylogenetic uncertainty (21,22) (Fig.…”

Section: Significancementioning

confidence: 99%

Implications of lemuriform extinctions for the Malagasy flora

Federman

Dornburg

Daly

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Madagascar's lemurs display a diverse array of feeding strategies with complex relationships to seed dispersal mechanisms in Malagasy plants. Although these relationships have been explored previously on a case-by-case basis, we present here the first comprehensive analysis of lemuriform feeding, to our knowledge, and its hypothesized effects on seed dispersal and the long-term survival of Malagasy plant lineages. We used a molecular phylogenetic framework to examine the mode and tempo of diet evolution, and to quantify the associated morphological space occupied by Madagascar's lemurs, both extinct and extant. Using statistical models and morphometric analyses, we demonstrate that the extinction of large-bodied lemurs resulted in a significant reduction in functional morphological space associated with seed dispersal ability. These reductions carry potentially far-reaching consequences for Malagasy ecosystems, and we highlight large-seeded Malagasy plants that appear to be without extant animal dispersers. We also identify living lemurs that are endangered yet occupy unique and essential dispersal niches defined by our morphometric analyses.anachronism | extinction | lemurs | Madagascar | seed dispersal

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Section: Significancementioning

confidence: 99%

Implications of lemuriform extinctions for the Malagasy flora

Federman

Dornburg

Daly

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…The difficulty in resolving energy pathways when potential sources are numerous and diverse is encountered in terrestrial (e.g., Blumenthal et al 2012), freshwater (e.g., Rasmussen 2010) and marine ecosystems (e.g., Baker et al 2013). It is particularly common at the boundary of aquatic and terrestrial systems, where there is a range of potential terrestrial, littoral, benthic macrophyte and microalgal sources (Bunn et al 2003, Connolly 2003, Bouillon and Connolly 2009.…”

Section: Introductionmentioning

confidence: 99%

Spatial analysis of carbon isotopes reveals seagrass contribution to fishery food web

Connolly

Waltham

2015

Ecosphere

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Citation: Connolly, R. M., and N. J. Waltham. 2015. Spatial analysis of carbon isotopes reveals seagrass contribution to fishery food web. Ecosphere 6(9):148. http://dx.doi.org/10.1890/ES14-00243.1Abstract. Despite the widespread use of carbon stable isotopes to distinguish among potential energy pathways in food webs, their usefulness is limited where potential basal carbon sources are numerous and diverse. We measured carbon isotope values of the major fisheries species, the mostly carnivorous Scylla serrata (giant mud crab), and potential basal, autotrophic sources supporting the food web. Conventional mixing modelling of autotroph and crab isotope data could not differentiate contributions from different sources. Pooling of modelled contributions from sources with similar isotope values indicated a role for organic matter from seagrass meadows or saltmarshes, but still did not define contributions well. Crab isotope data from a subsequent, spatially explicit survey of 14 sites, selected to represent different distances from key habitats, were analyzed using multiple regression. Crab isotope values showed a significant relationship with distance from seagrass (R 2 ¼ 0.87), but not with distance from mangroves or saltmarsh grass. Alongside seagrass meadows, crabs had very enriched isotope values, demonstrating their reliance on sources with enriched isotope values (seagrass and algae epiphytic on seagrass, 65-90% of their energy intake). At the site furthest from seagrass (21 km), crabs assimilated carbon primarily from depleted sources such as mangroves and terrestrial organic matter from coastal catchments (70-85%). Explicit spatial analysis of isotope data following a comprehensive survey revealed energy pathways not evident in conventional analyses.

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“…Scat is, however, an ideal substrate; it is abundant, turns over rapidly, and can be collected opportunistically without needing to capture the target animal. Both feeding studies [9,17–20] and field tests [7,12,13,21,22] support the notion that scat stable isotope values do reflect ingested diet for many organisms. Most of these studies have focused on mammalian herbivores rather than omnivores or carnivores.…”

Section: Introductionmentioning

confidence: 84%

“…Gross fecal analysis (GFA) techniques are also likely to severely overestimate the importance of small diet items [3–6]. Stable isotope analyses of scat have the potential to provide a quick and possibly more accurate means of gaining dietary information from scat while also allowing for non-invasive isotopic investigation of short-term dietary shifts that might otherwise be masked by long-term averaging in other animal tissues [7–14]. …”

Section: Introductionmentioning

confidence: 99%

Isotopic ecology of coyotes from scat and road kill carcasses: A complementary approach to feeding experiments

Reid

Koch

2017

PLoS ONE

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Scat is frequently used to study animal diets because it is easy to find and collect, but one concern is that gross fecal analysis (GFA) techniques exaggerate the importance of small-bodied prey to mammalian mesopredator diets. To capitalize on the benefits of scat, we suggest the analysis of scat carbon and nitrogen isotope values (δ13C and δ15N). This technique offers researchers a non-invasive method to gather short-term dietary information. We conducted three interrelated studies to validate the use of isotopic values from coyote scat: 1) we determined tissue-to-tissue apparent C and N isotope enrichment factors (ε13* and ε15*) for coyotes from road kill animals (n = 4); 2) we derived diet-to-scat isotope discrimination factors for coyotes; and 3) we used field collected coyote scats (n = 12) to compare estimates of coyote dietary proportions from stable isotope mixing models with estimates from two GFA techniques. Scat consistently had the lowest δ13C and δ15N values among the tissues sampled. We derived a diet-to-scat Δ13C value of -1.5‰ ± 1.6‰ and Δ15N value of 2.3‰ ± 1.3‰ for coyotes. Coyote scat δ13C and δ15N values adjusted for discrimination consistently plot within the isotopic mixing space created by known dietary items. In comparison with GFA results, we found that mixing model estimates of coyote dietary proportions de-emphasize the importance of small-bodied prey. Coyote scat δ13C and δ15N values therefore offer a relatively quick and non-invasive way to gain accurate dietary information.

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Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces

Cited by 49 publications

References 76 publications

Implications of lemuriform extinctions for the Malagasy flora

Implications of lemuriform extinctions for the Malagasy flora

Spatial analysis of carbon isotopes reveals seagrass contribution to fishery food web

Isotopic ecology of coyotes from scat and road kill carcasses: A complementary approach to feeding experiments

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