Effects of habitat fragmentation on foraging behaviour of tits and related species: does niche space vary in relation to size and degree of isolation of forest fragments?

We studied the winter foraging niches of tits and related species in deciduous forest fragments varying in size between 1 and 30 ha (plus one forest of 200 ha) in order to investigate the influence of forest fragmentation on foraging niches. Very few correlations between niche structure (foraging niche, width and overlap) and forest size or isolation turned out to be significant. This implies that either the species that disappear in small fragments are those that suffer most from competition (making the effect unmeasurable), or that competition is relatively unimportant for niche structure. In any case we find no evidence that foraging niches are strongly affected by the changes (in habitat and/or community structure) associated with fragmentation.