Resource information
It is recognized that wildlife populations exhibit spatial and temporal variability in patterns of species richness across heterogeneous landscapes. This phenomenon can prove problematic for environmental practitioners when attempting to complete comprehensive environmental assessments (EAs) with limited field surveys. A better understanding of regional spatio-temporal patterns in population dynamics should enhance site-level decision-making. In this study, the variability of seasonal data across the Credit River Watershed, southern Ontario, is assessed for a hierarchy of conservation measures including species richness, and two conservation wildlife response guilds based on primary habitat and area sensitivity. Bird populations were monitored at 24 forest monitoring plots across the watershed by the authors twice a season from 2003 to 2010 following the protocol of Environment Canada's Forest Bird Monitoring Program. The monitoring plots are located within four land management zones identified as 1) urban, 2) transitional, 3) escarpment and 4) rural. Data from the monitoring program are used to compare species richness among plots across the watershed and among land management zones. In addition, the variability of records from each plot over the 8year period was determined by means of the Coefficient of Variation (CV) statistic. The mean variability of these records at each site within each land management zone was determined in order to assess whether the temporal variability of bird records might affect the integrity of short term assessments. Finally, a one-way ANOVA was applied to learn whether the result of short-term assessments may be further compounded by differences in the response of selected bird guilds to landscape heterogeneity. The results show that there is a significant difference in mean richness of forest birds among the four management zones. The ANOVAs indicate that significant difference is due to the temporal variability of a) breeding forest interior birds rather than edge birds or generalist species and b) breeding area sensitive species rather than area non-sensitive species. Recommendations are made that environmental assessments targeting forest interior bird populations need to plan sampling strategies that recognize this variability, especially for sites within the transitional and urban zones. Planning in the transition or urbanizing landscape should incorporate landscape ecology principles to sustain current levels of richness in forest species.
