We. Magnusson et al., Size and carbon acquisition in lizards from Amazonian savanna: Evidence from isotope analysis, ECOLOGY, 82(6), 2001, pp. 1772-1780
We studied the effects of lizard size, and availability of C-3 and C-4 plan
ts, on stable carbon-isotope (delta C-13) ratios of lizards in an Amazonian
savanna. Availability of C-3 and C-4 plants was estimated from 500-point q
uadrats in each of 38 plots of 3.75 ha. Ratios of delta C-13 in muscle tiss
ue were used to estimate the contribution:, of C-3- and C-4-based food chai
ns to the diets of four species of lizards: Cnemidophorus lemiscatus, Kentr
opyx slriata, Ameiva ameiva, and Anolis auratus. The relative contributions
of C-3 and C-4 plants to the diets of the lizards were affected by the ext
ent of shrub cover in C. lemniscatus, A. auratus, and possibly in K. striat
a. However, there was a strong effect of lizard size among and within lizar
d species. These results are at variance with a previous evaluation of diet
overlap among size classes of these species that was based on overlap in p
rey taxonomic categories. This indicates that species and/or size classes o
f predators on arthropods may obtain their energy from food chains based on
different autotrophic sources. despite high overlap in the taxonomic categ
ories of prey.