Synopsis:
This study investigated the magnitude of change in landscape structure resulting from road and logging since the onset of timber harvesting in 1950. Overall, roads were found to have had a greater impact on landscape structure than logging. A three-fold increase in road density between 1950 and 1993 accounted for most of the changes in landscape configuration including mean patch size, edge density, and core area. Change in landscape structure varied as a function of landscape extent. At a large scale of 228,000 ha, change in landscape change over time was trivial, suggesting that the landscape is capable of incorporating disturbances with minimal impact. At intermediate scales of 1000-10,000 ha, change in landscape structure was very evident, suggesting that there is an optimal range of scales for detecting changes in landscape structure in the study area.
Conclusions:
Overall, roads were found to have had a greater impact on landscape structure than logging. A three-fold increase in road density between 1950 and 1993 accounted for most of the changes in landscape configuration including mean patch size, edge density, and core area. Change in landscape structure varied as a function of landscape extent.
Thresholds/Learnings:
Conservative estimate of edge effect: 50-100m
Caveats:
Without a framework within which to interpret landscape structure (i.e. a range of expected values for landscape structure variability), it was difficult to interpret the findings of this study in a meaningful way.
