Meeting Abstract

21.5  Wednesday, Jan. 4  From Tissues to Landscapes: Using Physiology to Answer Landscape Level Questions in Large Mammals DUNKIN, R.C.*; TINKER, M.T.; WILLIAMS, T.M.; Univ. of California Santa Cruz; USGS-Western Ecological Research Center; Univ. of California Santa Cruz

Elephants, the largest land mammal, are highly dependent on surface water for efficient heat dissipation. As a result, they must shuttle between two critical resources, water holes to satisfy thermoregulatory demands and quality foraging areas to meet nutritional needs. This lifestyle has physiological consequences for the elephant and substantial landscape-level impacts associated with elephant grazing. Here we examine how climate interacts with relative food abundance, thermal physiology and water use patterns of elephants. Relationships between ambient temperature (Ta), water flux, and heat transfer of adult elephants (n=13, mean body mass=3801kg) were empirically measured and used to construct a physiology–climate based stochastic dynamic state variable model (SDSV). Using this model, four food quantity-climate scenarios were used to explore how limitations in surface water, ambient temperature, and food abundance/quality together influence spatial-use patterns and habitat impacts by elephants. Elephants relied on evaporative cooling to dissipate more than 100% of resting heat production at Ta≥28oC. This temperature-water relationship resulted in predicted mean ranging distances from water that were more than 4 fold greater in habitats with mild climate (Tamax=21.2oC) relative to warmer climates (Tamax=32.9oC). Reduction of elephant abundance in overcrowded reserves using surface water management has gained recent interest, yet determination of whether a population is water limited has proven difficult. These data demonstrate that physiology based approaches to landscape level patterns can provide powerful process driven tools for evaluating habitat needs and impacts of large mammals. Supported by WWQ and SICB.