Climate-driven flucturation in surface-water availability and the buffering role of artificial pumping in an African savanna : potential implication for herbivore dynamics
In arid and semiarid environments surface-water strongly constrains the distribution and abundance of large herbivores during the dry season. Surprisingly, we know very little about its variability in natural ecosystems. Here we used long-term data on the dry-season occurrence of water at individual waterholes to model the surface-water availability across Hwange National Park, Zimbabwe, under contrasted climatic and management scenarios. Without artificial pumping only 19.6% of the park occurred within 5 km of water under average climatic conditions. However surface-water availability was strongly influenced by annual rainfall, and over 20 years the variability of the surface area of the park occurring within 5 km of water was slightly larger than the variability of rainfall. This contrasts with the usual buffered response of vegetation production to rainfall fluctuations, and suggests that the variability in dry-season foraging range determined by surface-water availability could be the main mechanism regulating the population dynamics of large herbivores in this environment. Artificial pumping increased surface-water availability and reduced its variability over time. Because changes in surface-water avail-ability could cause the greatest changes in forage availability for large herbivores, we urge ecologists to investigate and report on the variability of surface-water in natural ecosystems, particularly where rapid climate changes are expected.
| Main Authors: | , , |
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| Format: | article biblioteca |
| Language: | eng |
| Subjects: | L20 - Écologie animale, |
| Online Access: | http://agritrop.cirad.fr/541968/ http://agritrop.cirad.fr/541968/1/document_541968.pdf |
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