Effect of land use and climate on the diversity of moth guilds with different habitat specialization

An assemblage of moth species at a suburb of Prague (50°5′11″N,14°18′06″E) was monitored by a highly efficient mercury light trap for 23 years (1967–1976, 1980–1992). Species caught were divided into guilds according to habitat specialisation, and analysed using species richness S , Shannon’s diversity H and evenness J as the response variables, and the individual years of monitoring and effects of mean annual temperature and precipitation as the explanatory variables. Overall, 424 species were recorded: 25 early successional arable land species (43% of all caught individuals), 116 forest species feeding on trees and shrubs, 33 forest species feeding on woodland herbs and lichens, 92 forest-steppe species, 116 grassland species, 28 wetland species, and 14 non-specialized generalists. The diversity of habitat-specialised species responded mainly to land use changes, whereas the diversity of generalists reflected long-term meteorological trends. Species richness of specialists whose habitats in the vicinity of the trap have declined in extent decreased, the numbers of those whose habitats remained intact did not exhibit any particular trend, whereas the numbers of generalists increased, and their diversity positively responded to warming. It is concluded that the habitat specialists and generalists react to environmental changes differently. Non-specialised species appear more sensitive indicators of climate changes than habitat specialists because for the latter the indication of climate changes can be overlaid by changes in habitat use.