PATTERNS OF FOREST USE AND ENDEMISM IN RESIDENT BIRD COMMUNITIES OF NORTH-CENTRAL MICHOACAN, MEXICO

We compared breeding avian communities among 11 habitat types in north -central Michoacan, Mexico, to determine patterns of forest use by end emic and nonendemic resident species. Point counts of birds and vegeta tion measurements were conducted at 124 sampling localities from May t hrough July, in 1994 and 1995. Six native forest types sampled were pi ne, pine-oak, oak-pine, oak, fir, and cloud forests; three habitat typ es were plantations of Eucalytus, pine, and mixed species; and the rem aining two habitats were shrublands and pastures. Pastures had lower b ird-species richness and abundance than pine, oak-pine, and mixed-spec ies plantations. Pine forests had greater bird abundance and species r ichness than oak forests and shrublands. Species richness and abundanc e of endemics were greatest in fir forests, followed by cloud forests. Bird abundance and richness significantly increased with greater tree -layer complexity, although sites with intermediate tree complexity al so supported high abundances. When detrended correspondence-analysis s cores were plotted for each site, bird species composition did not dif fer substantially among the four native oak-and-pine forest types, but cloud and fir forests, Eucalyptus plantations, and mixed-species plan tations formed relatively distinct groups. Plantations supported a mix ture of species found in native forests, shrublands, and pastures. Pas tures and shrublands shared many species in common, varied greatly amo ng sites in bird-species composition, and contained more species speci fic to these habitats than did forest types. (C) 1998 Elsevier Science B.V.