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Definiendo la fragmentación del bosque en base al ancho de los corredores: Influencia de los corredores divisores del bosque angostos sobre los pájaros nidificantes del bosque en el sudeste de Nueva Jersey
Author(s) -
Rich Adam C.,
Dobkin David S.,
Niles Lawrence J.
Publication year - 1994
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1046/j.1523-1739.1994.08041109.x
Subject(s) - transect , forest fragmentation , geography , fragmentation (computing) , abundance (ecology) , ecology , old growth forest , forestry , environmental science , habitat , biology
In studies of forest fragmentation, a fundamental inconsistency exists in the distance criterion used to define the discreteness of forest fragments. We examined three types of ubiquitous, narrow, forest‐dividing corridors for effects that influence the relative abundance and community composition of forest‐nesting birds. Fixed‐radius (100‐meter) point counts were conducted on 54 transects established along three width classes of corridors: unpaved roads (8 meters wide), paved roads (16 meters wide), and powerlines (23 meters wide). Transect locations were distributed equally among corridor edge, forest margin 100 meters from corridor edge, and forest interior 300 meters from corridor edge. Forest‐interior species of Neotropical migrants had significantly reduced relative abundances on edge transects along 16‐ and 23‐meter corridors, compared with 8‐meter corridors and with forest interior points along all three corridor‐width classes. At a landscape scale, the consequences of apparently small reductions in forest area by the presence of narrow forest‐dividing corridors may be cumulatively significant for abundances of forest‐interior species. Brown‐headed Cowbirds were more abundant than 20 of 21 forest‐interior Neotropical migrants. We found surprisingly high abundances of cowbirds associated with narrow forest‐dividing corridors, especially those with mowed grass. Corridor widths as narrow as 8 meters produce forest fragmentation effects in part by attracting cowbirds and nest predators to corridors and adjacent forest interiors. The most serious implication of this study is that narrow forest‐dividing corridors may function as ecological traps for forest‐interior Neotropical migrants. We suggest that these widespread corridors may be inconspicuous but important contributors to declines of forest‐interior nesting species in eastern North America.