Rabbits, refuges and resources : how foraging of herbivores is affected by living in burrows

Small herbivores such as rabbits, pika and marmots create spatial patterns in vegetation around their burrows by grazing. This PhD thesis focuses on these refuge-living herbivores.<o:p></o:p></span>By performing experiments with rabbits, he showed that looking for predators causes the spatial patterns: this<span class=GramE>costs</span>more foraging time as the burrow is farther, causing a preference for foraging close to the burrow. The animals can stay close to their burrow when the vegetation grows, but are forced to graze larger areas as plant growth declines, and are negatively affected by the seasonal deterioration of plant quality. Models predict that this will have repercussions for population density, but can be countered by large grazers. Ir. Dekker also showed that large grazers also affect refuge living herbivores through changes in vegetation structure: this alters the timing of their activity.<o:p></o:p></span>The spatial variation in grazing by refuge living herbivores potentially increases variation in structure and diversity in the vegetation. That way, these small, refuge living herbivores are an important addition to large grazers