  Competition is a major force in structuring ecological communities. The
strength of competition can be measured using the concept of a niche. A niche
comprises the set of requirements of an organism in terms of habitat,
environment and functional role. The more niches overlap, the stronger
competition is. The niche breadth is a measure of specialization: the smaller
the niche space of an organism, the more specialized the organism is. It
follows that, everything else being equal, generalists tend to be more
competitive than specialists. In this paper, we compare the outcome of
competition among generalists and specialists in a spatial versus a nonspatial
habitat in a heterogeneous environment. Generalists can utilize the entire
habitat, whereas specialists are restricted to their preferred habitat type. We
find that although competitiveness decreases with specialization, specialists
are more competitive in a spatial than in a nonspatial habitat as patchiness
increases.

Probability