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Trophic level delineation and resource partitioning in a South African afromontane forest bird community using carbon and nitrogen stable isotopes
Author(s) -
Symes Craig T.,
Woodborne Stephan M.
Publication year - 2010
Publication title -
african journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.499
H-Index - 54
eISSN - 1365-2028
pISSN - 0141-6707
DOI - 10.1111/j.1365-2028.2009.01201.x
Subject(s) - trophic level , isotopes of carbon , ecology , δ15n , δ13c , isotopes of nitrogen , niche , range (aeronautics) , ecosystem , stable isotope ratio , biology , nitrogen , chemistry , total organic carbon , physics , quantum mechanics , materials science , organic chemistry , composite material
Southern African forests are naturally fragmented yet hold a disproportionately high number of bird species. Carbon and nitrogen stable isotopes were measured in feathers from birds captured at Woodbush (n = 27 species), a large afromontane forest in the eastern escarpment of Limpopo province, South Africa. The δ 13 C signatures of a range of forest plants were measured to categorise the food base. Most plants sampled, including two of five grass species, had δ 13 C signatures typical of a C 3 photosynthetic pathway (−29.5 ± 1.9‰). Three grass species had a C 4 signature (−12.0 ± 0.6‰). Most bird species had δ 13 C values representing a predominantly C 3 ‐based diet (−24.8‰ to −20.7‰). δ 15 N values were as expected, with higher levels of enrichment associated with a greater proportion of dietary animal matter. The cohesive isotopic niche defining most species (n = 22), where the ranges for δ 13 C and δ 15 N were 2.4‰ and 3.4‰, respectively, highlight the difficulties in understanding diets of birds in a predominantly C 3 ‐based ecosystem using carbon and nitrogen stable isotopes. However, variation in isotopic values between and within species provides insight into possible niche width and the use of resources by different birds within a forest environment.