Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river

Douglas J. McCauley, Todd E. Dawson, Mary E. Power, Jacques C Finlay, Mordecai Ogada, Drew B. Gower, Kelly Caylor, Wanja D. Nyingi, John M. Githaiga, Judith Nyunja, Francis H. Joyce, Rebecca L. Lewison, Justin S. Brashares

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The common hippopotamus, Hippopotamus amphibius, transports millions of tons of organic matter annually from its terrestrial feeding grounds into aquatic habitats. We evaluated whether carbon stable isotopes (δ13C) can be used as tracers for determining whether H. amphibius-vectored allochthonous material is utilized by aquatic consumers. Two approaches were employed to make this determination: (1) lab-based feeding trials where omnivorous river fish were fed a H. amphibius dung diet and (2) field sampling of fish and aquatic insects in pools with and without H. amphibius. Lab trials revealed that fish fed exclusively H. amphibius dung exhibited significantly more positive δ13C values than fish not fed dung. Fish and aquatic insects sampled in a river pool used for decades by H. amphibius also exhibited more positive δ13C values at the end of the dry season than fish and insects sampled from an upstream H. amphibius-free reference pool. Fish sampled in these same pools at the end of the wet season (high flow) showed no significant differences in δ13C values, suggesting that higher flows reduced retention and use of H. amphibius subsidies. These data provide preliminary evidence that δ13C values may be useful, in certain contexts, for quantifying the importance H. amphibius organic matter.

Original languageEnglish (US)
Article number52
JournalEcosphere
Volume6
Issue number4
DOIs
StatePublished - Apr 1 2015

Fingerprint

Hippopotamus
stable isotopes
carbon isotope
stable isotope
rivers
carbon
nutrient
nutrients
fish
river
insect
aquatic insects
feces
organic matter
feeding ground
Hippopotamus amphibius
wet season
dry season
aquatic habitat
subsidies

Keywords

  • Allochthonous organic matter
  • Aquatic invertebrate
  • Carbon
  • Fish
  • Freshwater
  • Hippopotamus amphibius
  • Hydrology
  • Isotope
  • Kenya
  • River
  • Subsidy
  • Watershed

Cite this

Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river. / McCauley, Douglas J.; Dawson, Todd E.; Power, Mary E.; Finlay, Jacques C; Ogada, Mordecai; Gower, Drew B.; Caylor, Kelly; Nyingi, Wanja D.; Githaiga, John M.; Nyunja, Judith; Joyce, Francis H.; Lewison, Rebecca L.; Brashares, Justin S.

In: Ecosphere, Vol. 6, No. 4, 52, 01.04.2015.

Research output: Contribution to journalArticle

McCauley, DJ, Dawson, TE, Power, ME, Finlay, JC, Ogada, M, Gower, DB, Caylor, K, Nyingi, WD, Githaiga, JM, Nyunja, J, Joyce, FH, Lewison, RL & Brashares, JS 2015, 'Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river', Ecosphere, vol. 6, no. 4, 52. https://doi.org/10.1890/ES14-00514.1
McCauley, Douglas J. ; Dawson, Todd E. ; Power, Mary E. ; Finlay, Jacques C ; Ogada, Mordecai ; Gower, Drew B. ; Caylor, Kelly ; Nyingi, Wanja D. ; Githaiga, John M. ; Nyunja, Judith ; Joyce, Francis H. ; Lewison, Rebecca L. ; Brashares, Justin S. / Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river. In: Ecosphere. 2015 ; Vol. 6, No. 4.
@article{c1b430982a4c49068113bf613846a951,
title = "Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river",
abstract = "The common hippopotamus, Hippopotamus amphibius, transports millions of tons of organic matter annually from its terrestrial feeding grounds into aquatic habitats. We evaluated whether carbon stable isotopes (δ13C) can be used as tracers for determining whether H. amphibius-vectored allochthonous material is utilized by aquatic consumers. Two approaches were employed to make this determination: (1) lab-based feeding trials where omnivorous river fish were fed a H. amphibius dung diet and (2) field sampling of fish and aquatic insects in pools with and without H. amphibius. Lab trials revealed that fish fed exclusively H. amphibius dung exhibited significantly more positive δ13C values than fish not fed dung. Fish and aquatic insects sampled in a river pool used for decades by H. amphibius also exhibited more positive δ13C values at the end of the dry season than fish and insects sampled from an upstream H. amphibius-free reference pool. Fish sampled in these same pools at the end of the wet season (high flow) showed no significant differences in δ13C values, suggesting that higher flows reduced retention and use of H. amphibius subsidies. These data provide preliminary evidence that δ13C values may be useful, in certain contexts, for quantifying the importance H. amphibius organic matter.",
keywords = "Allochthonous organic matter, Aquatic invertebrate, Carbon, Fish, Freshwater, Hippopotamus amphibius, Hydrology, Isotope, Kenya, River, Subsidy, Watershed",
author = "McCauley, {Douglas J.} and Dawson, {Todd E.} and Power, {Mary E.} and Finlay, {Jacques C} and Mordecai Ogada and Gower, {Drew B.} and Kelly Caylor and Nyingi, {Wanja D.} and Githaiga, {John M.} and Judith Nyunja and Joyce, {Francis H.} and Lewison, {Rebecca L.} and Brashares, {Justin S.}",
year = "2015",
month = "4",
day = "1",
doi = "10.1890/ES14-00514.1",
language = "English (US)",
volume = "6",
journal = "Ecosphere",
issn = "2150-8925",
publisher = "Ecological Society of America",
number = "4",

}

TY - JOUR

T1 - Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river

AU - McCauley, Douglas J.

AU - Dawson, Todd E.

AU - Power, Mary E.

AU - Finlay, Jacques C

AU - Ogada, Mordecai

AU - Gower, Drew B.

AU - Caylor, Kelly

AU - Nyingi, Wanja D.

AU - Githaiga, John M.

AU - Nyunja, Judith

AU - Joyce, Francis H.

AU - Lewison, Rebecca L.

AU - Brashares, Justin S.

PY - 2015/4/1

Y1 - 2015/4/1

N2 - The common hippopotamus, Hippopotamus amphibius, transports millions of tons of organic matter annually from its terrestrial feeding grounds into aquatic habitats. We evaluated whether carbon stable isotopes (δ13C) can be used as tracers for determining whether H. amphibius-vectored allochthonous material is utilized by aquatic consumers. Two approaches were employed to make this determination: (1) lab-based feeding trials where omnivorous river fish were fed a H. amphibius dung diet and (2) field sampling of fish and aquatic insects in pools with and without H. amphibius. Lab trials revealed that fish fed exclusively H. amphibius dung exhibited significantly more positive δ13C values than fish not fed dung. Fish and aquatic insects sampled in a river pool used for decades by H. amphibius also exhibited more positive δ13C values at the end of the dry season than fish and insects sampled from an upstream H. amphibius-free reference pool. Fish sampled in these same pools at the end of the wet season (high flow) showed no significant differences in δ13C values, suggesting that higher flows reduced retention and use of H. amphibius subsidies. These data provide preliminary evidence that δ13C values may be useful, in certain contexts, for quantifying the importance H. amphibius organic matter.

AB - The common hippopotamus, Hippopotamus amphibius, transports millions of tons of organic matter annually from its terrestrial feeding grounds into aquatic habitats. We evaluated whether carbon stable isotopes (δ13C) can be used as tracers for determining whether H. amphibius-vectored allochthonous material is utilized by aquatic consumers. Two approaches were employed to make this determination: (1) lab-based feeding trials where omnivorous river fish were fed a H. amphibius dung diet and (2) field sampling of fish and aquatic insects in pools with and without H. amphibius. Lab trials revealed that fish fed exclusively H. amphibius dung exhibited significantly more positive δ13C values than fish not fed dung. Fish and aquatic insects sampled in a river pool used for decades by H. amphibius also exhibited more positive δ13C values at the end of the dry season than fish and insects sampled from an upstream H. amphibius-free reference pool. Fish sampled in these same pools at the end of the wet season (high flow) showed no significant differences in δ13C values, suggesting that higher flows reduced retention and use of H. amphibius subsidies. These data provide preliminary evidence that δ13C values may be useful, in certain contexts, for quantifying the importance H. amphibius organic matter.

KW - Allochthonous organic matter

KW - Aquatic invertebrate

KW - Carbon

KW - Fish

KW - Freshwater

KW - Hippopotamus amphibius

KW - Hydrology

KW - Isotope

KW - Kenya

KW - River

KW - Subsidy

KW - Watershed

UR - http://www.scopus.com/inward/record.url?scp=84928776030&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84928776030&partnerID=8YFLogxK

U2 - 10.1890/ES14-00514.1

DO - 10.1890/ES14-00514.1

M3 - Article

VL - 6

JO - Ecosphere

JF - Ecosphere

SN - 2150-8925

IS - 4

M1 - 52

ER -