Comments On “Assembling A Diet From Different Places”
Prins and Van Langevelde (Chapter 7) use a linear-programming model to assess the extent to which ruminants of different size are able to satisfy their nutrient, energy and protein requirements from a landscape composed of two ‘food’ patches that differ in their relative densities of these important nutritional variables. Amongst their findings they conclude that, overall, small species are less able to balance their nutritional requirements when patches are widely dispersed than are large species, and are, therefore, more likely to be found in fine-grained (i.e., more closely dispersed food patches) than in course-grained ecosystems. Whilst this is an interesting and testable hypothesis, I will argue that it is the ‘foodscape’, not the landscape, that foraging animals respond to. My view is that the conclusions are an artefact of the model description rather than an actuality of the real world in which ruminants forage for a living. I posit that the dispersion of food in the landscape is a species-specific construct with the result that the foodscape of two species foraging in the same landscape will differ because of their differing views of food and their differing ability to select that food from the array of non-food on offer (see also Underwood 1983).