TY - JOUR
T1 - Extensive browsing by a conventional grazer? Stable carbon isotope analysis reveals extraordinary dietary flexibility among Sanga cattle of North Central Namibia
AU - Radloff, Frans G.T.
AU - Waal, Cornelis Van der
AU - Bond, Alexander L.
N1 - Author not employed by UHI at time of publication.
PY - 2013/8/1
Y1 - 2013/8/1
N2 - Intraspecies dietary flexibility, such as variable consumption of graze vs. browse in herbivores, has received scant attention on a spatial scale despite growing evidence of substantial variability within and among populations, especially in bovids. Here, we report on extraordinary differences in cattle diet among two communal pasture areas across seasons in northern Namibia: King Nehale (KN, open grassland) and Okongo (OK, dense woodland). Percentage C3 browse and C4 grass consumption was determined from δ13C values of dung samples, using a Bayesian stable-isotope mixing model (SIAR - stable isotope analysis in R). During the wet and early dry season, KN cattle consumed 11 and 19% browse, respectively, and the OK cattle consumed 84% browse. At the end of the dry season, the browse intake of KN cattle increased to 33% while that of OK cattle decreased to 55%. Vegetation structure influenced the graze/browse consumption strongly in both areas. A better understanding of this extraordinary dietary flexibility is imperative as anthropogenically driven habitat change is projected to lead to the extinction of perceived grazing specialists.
AB - Intraspecies dietary flexibility, such as variable consumption of graze vs. browse in herbivores, has received scant attention on a spatial scale despite growing evidence of substantial variability within and among populations, especially in bovids. Here, we report on extraordinary differences in cattle diet among two communal pasture areas across seasons in northern Namibia: King Nehale (KN, open grassland) and Okongo (OK, dense woodland). Percentage C3 browse and C4 grass consumption was determined from δ13C values of dung samples, using a Bayesian stable-isotope mixing model (SIAR - stable isotope analysis in R). During the wet and early dry season, KN cattle consumed 11 and 19% browse, respectively, and the OK cattle consumed 84% browse. At the end of the dry season, the browse intake of KN cattle increased to 33% while that of OK cattle decreased to 55%. Vegetation structure influenced the graze/browse consumption strongly in both areas. A better understanding of this extraordinary dietary flexibility is imperative as anthropogenically driven habitat change is projected to lead to the extinction of perceived grazing specialists.
KW - Bos taurus africanus
KW - bovid
KW - browser
KW - carbon-13
KW - diet
KW - grazer
KW - herbivore
KW - isotope ecology
KW - isotope measurements and methods
UR - http://www.scopus.com/inward/record.url?scp=84885928812&partnerID=8YFLogxK
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U2 - 10.1080/10256016.2013.789025
DO - 10.1080/10256016.2013.789025
M3 - Article
C2 - 23859529
AN - SCOPUS:84885928812
SN - 1025-6016
VL - 49
SP - 318
EP - 324
JO - Isotopes in Environmental and Health Studies
JF - Isotopes in Environmental and Health Studies
IS - 3
ER -