21418208
not annotated - annotated - LINNAEUS only
Soil nutrient status determines how elephant utilize trees and shape environments.
1. Elucidation of the mechanism determining the spatial scale of patch selection by herbivores has been complicated by the way in which resource availability at a specific scale is measured and by vigilance behaviour of the herbivores themselves. To reduce these complications, we studied patch selection by an animal with negligible predation risk, the African elephant. 2. We introduce the concept of nutrient load as the product of patch size, number of patches and local patch nutrient concentration. Nutrient load provides a novel spatially explicit expression of the total available nutrients a herbivore can select from. 3. We hypothesized that elephant would select nutrient-rich patches, based on the nutrient load per 2500 m(2) down to the individual plant scale, and that this selection will depend on the nitrogen and phosphorous contents of plants. 4. We predicted that elephant would cause more adverse impact to trees of lower value to them in order to reach plant parts with higher nutrient concentrations such as bark and root. However, elephant should maintain nutrient-rich trees by inducing coppicing of trees through re-utilization of leaves. 5. Elephant patch selection was measured in a homogenous tree species stand by manipulating the spatial distribution of soil nutrients in a large field experiment using NPK fertilizer. 6. Elephant were able to select nutrient-rich patches and utilized Colophospermum mopane trees inside these patches more than outside, at scales ranging from 2500 down to 100 m(2) . 7. Although both nitrogen and phosphorus contents of leaves from C. mopane trees were higher in fertilized and selected patches, patch choice correlated most strongly with nitrogen content. As predicted, stripping of leaves occurred more in nutrient-rich patches, while adverse impact such as uprooting of trees occurred more in nutrient-poor areas. 8. Our results emphasize the necessity of including scale-dependent selectivity in foraging studies and how elephant foraging behaviour can be used as indicators of change in the availability of nutrients.
Ann file
T1 Out-of-scope 36 44 elephant
T2 Species 439 455 African elephant
N2 Reference T2 Taxonomy:9785
T3 Out-of-scope 737 745 elephant
T4 Out-of-scope 968 976 elephant
T5 Out-of-scope 1139 1147 elephant
T6 Out-of-scope 1252 1260 Elephant
T7 Species 1437 1445 Elephant
N7 Reference T7 Taxonomy:9785
T8 Species 1501 1522 Colophospermum mopane
N8 Reference T8 Taxonomy:162715
T9 Species 1681 1690 C. mopane
N9 Reference T9 Taxonomy:162715
T10 Out-of-scope 2074 2082 elephant
N11 Reference T1 Taxonomy:9780 Elephantidae
N1 Reference T3 Taxonomy:9780 Elephantidae
N3 Reference T4 Taxonomy:9780 Elephantidae
N4 Reference T5 Taxonomy:9780 Elephantidae
N5 Reference T6 Taxonomy:9780 Elephantidae
N6 Reference T10 Taxonomy:9780 Elephantidae