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STRUCTURE AND COMPOSITION OF RIPARIAN BOREAL FOREST: NEW METHODS FOR ANALYZING EDGE INFLUENCE
Author(s) -
Harper K. A.,
Macdonald S. E.
Publication year - 2001
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/0012-9658(2001)082[0649:sacorb]2.0.co;2
Subject(s) - transect , ecotone , taiga , gradient analysis , understory , environmental science , boreal , ecology , riparian forest , riparian zone , canopy , geography , forestry , ordination , habitat , biology
Riparian ecotones at lakeshore edges are prominent features on the heterogeneous boreal forest landscape. We introduce a new method (the critical values approach), which incorporates inherent variability in interior forest, to quantify distance of edge influence at lakeshore forest edges. We use this method to examine the variation in forest structure and composition along the lakeshore forest edge‐to‐interior gradient in the mixedwood boreal forest. Our objectives were: (1) to quantify distance of edge influence for forest structure and composition at lakeshore forest edges; and (2) to investigate spatial pattern in vegetation along the edge‐to‐interior gradient. Trees, coarse woody material, saplings, shrubs, and herbs were sampled in plots at varying distances along 200‐m transects established perpendicular to lakeshore forest edges. Distance of edge influence was determined by comparing mean values at different positions along the transect to critical values established from a randomization test of interior forest data. The spatial pattern of four selected species along the edge‐to‐interior gradient was assessed using split moving window analysis and wavelet analysis. The results suggest that a distinct lakeshore forest edge community exists. This community was ∼40 m wide and was characterized by greater structural diversity, larger amounts of coarse woody material, and more saplings and mid‐canopy trees than interior forest. Distance of edge influence for understory composition was generally greater than for forest structure. Patterns of response for different species along the edge‐to‐interior gradient were related to shade tolerance. Lakeshore forest edges are distinct landscape elements, but their prominence depends on the reference forest, species, and scale.