Thursday, May 29, 2008 - 2:15 PM
566

Zagat's Guide for the finned set? site-specific variation in conspecific C:N ratios may reveal differences in food availability and habitat quality

Karen H. Gaines, Biology, University of New Mexico, MSC03-2020, Albuquerque, NM 87131

During the process of starvation, carbon-rich molecules such as carbohydrates and lipids tend to be broken down first in a consumer’s body, resulting in decreasing tissue C:N ratios as starvation proceeds.  Therefore, the elemental composition of an organism can provide valuable information about the nutritional status and diet quality of that individual when compared to its conspecifics in similar habitats.  While attempting to characterize the degree of spatial variability in habitat quality and food web structure in a series of desert sinkholes, the C:N ratios of conspecific fish and aquatic invertebrates were compared across sites and found to exhibit significant site-specific differences.  For instance, the mean C:N ratio for Pecos pupfish in one site was significantly higher than C:N ratios in the other three sinkholes in which it is found, while the mean C:N ratios for two kinds of predatory odonate larvae and corixid adults in that site were lower than values for their conspecifics elsewhere.  These and other differences in conspecific elemental ratios suggest that superficially similar sites may represent habitats of dramatically different qualities for focal taxa, and that species introduction efforts should be made with these differences in mind.


Web Page: stoichiometry, C:N ratio, food web

See more of Food Webs III
See more of Contributed Sessions

See more of The Nabs 56th Annual Meeting (25-28 May, 2008)