Guild indicator species on a landscape scale-an example with four avian habitat

Abstract

The ability to predict the patch occurrence of a deciduous forest bird guild through an indicator species was tested using published data . Except for the indicator, the Longtailed Tit (LT), the guild consisted of the Marsh Tit (MT), the Blue Tit (BT) and the Lesser Spotted Woodpecker (LW). All single species, as well as the entire guild, occurred more often like LT than expected by chance. Over all, 86% of the guild occurred in concurrence with LT. When LT was present the mean number of guild species was 3.52 and when absent 0.79. The occurrence pattern of the guild did not change when one multi-sampled region in Sweden was compared with patches scattered throughout four countries, whereas concurrence was more significant in studies from the boreal zone than from the nemoral zone. The guild showed a nested structure in patch occupancy, where the occurrence of LW strongly predicted that of the entire guild. However, because of the better overall statistical agreement in relation to the guild, the Long-tailed Tit, or rather, its known thresholds regarding habitat fragmentation, are suggested as suitable indicators for the occurrence of this guild.