Kangaroo metabolism does not cause the relationship between bone collagen δ
15N and water availability
You are here
Murphy, BP and Bowman, DMJS, Kangaroo metabolism does not cause the relationship between bone collagen δ
15N and water availability, Functional Ecology, 20, (6) pp. 1062-1069. ISSN 0269-8463 (2006) [Refereed Article]
1. A negative relationship between water availability and the abundance of 15N relative to 14N (expressed as δ15N) in the bone collagen of herbivores has been widely reported. However, the relative importance of dietary δ15N and animal metabolism in producing this effect remains unclear. 2. To evaluate the relative importance of these two factors, we examined variation in δ15N of both grass foliage and kangaroo (Macropus spp.) bone collagen. We assessed whether the offset between grass and bone collagen δ15N was constant with respect to water availability. 3. An index of water availability (annual actual evapotranspiration/annual potential evapotranspiration) explained a considerable proportion of the variation in both grass δ15N (R2 = 0.40) and bone collagen δ15N (R2 = 0.57), and the slopes of these negative relationships were similar, with a near-constant δ15N offset between grass foliage and bone collagen. 4. This finding suggests that dietary δ15N is the main cause of the negative relationship between kangaroo bone collagen δ15N and water availability, with metabolic factors having little discernible effect. © 2006 The Authors.
Repository Staff Only:
item control page