Foraging strategies on rangelands: Effects on intake and animal performance

Abstract

Rangelands exhibit extreme spatial and temporal variability in forage quality and availability. The animals that utilise these rangelands have consequently evolved a range of foraging strategies in an attempt to cope with this variability and maintain nutrient intake. In general, animals respond to and exploit spatial variability at all scales by selecting those items or units which optimise the intake of digestible nutrients and hence animal production. Animals similarly employ a variety of strategies to cope with temporal variability on rangelands. These strategies may include adjusting foraging behaviour and/or exploiting critical resources or resource areas to buffer temporal variability in feed quality or supply.

While current understanding of short term foraging processes operating in small scale, relatively simple environments is acceptable, our understanding and ability to predict longer term processes operating at the larger scale in more complex rangeland environments is poor. Consequently, our ability to predict foraging behaviour on rangelands and hence animal intake and production or the impact of animals on specific areas is severely limited. The major challenge therefor, is to advance our current information, theory and models upwards from the small scale to accommodate and realistically simulate, the larger, more complex systems operating on rangelands.