Population trends of North Finnish land birds in relation to their habitat selection and changes in forest structure

摘要: Long-term trends in the 22 most abundant land bird species breeding northern Finland were related to their habitat selection patterns. Independent data sets used describe long-term population (POP), edge preferences (EDGE) and effects of changing age structure forests on density (AGE). AGE combined present birds with North Finnish from 1950s 1970s. EDGE correlated positively though not significantly POP. When taken into account simultaneously, a significant correlation POP emerged (67% variance accounted). Southern an exception; seem depend changes southern Finland. The sedentary old have plummeted during recent decades results for this group (Parus montanus, P. cristatus, cinctus, Certhia familiaris, Perisoreus infaustus) agreed well finding that fragmentation are mainly responsible among forest north. Our seemingly indicate close tracking environmental resources by community. However, as geographical scale study is broad (northern opposed one site) temporal rather than years, simple saturation hypothesis inevitable inference data; if there resources, it terms populations whole An alternative provided numbers high-quality low-quality sites; view, regional pattern result complicated dynamics mosaic local populations.