Grant: Discovery Grants Program - Individual

Ultimately, natural resource management influences individual organisms. It is often assumed that individuals of mobile species will simply move elsewhere to avoid newly-disturbed areas but few studies have been conducted to confirm this. In 2006, we established a set of experimental plots and we marked nearly all males of a migratory bird species (Ovenbird) prior to the treatment of half of these plots through selection harvesting during the next winter. This harvest treatment removed 30-40% of the wood volume. We have monitored the response of Ovenbird populations and individually-marked males ever since. We have also monitored the response of the Brown Creeper, another forest bird species that is a year-round resident or short-distance migrant in the study region. Surprisingly, in the first year after harvesting, almost as many male Ovenbirds returned to their territory as in the controls. However, 4 years after, a lower proportion of birds from the 2006 cohort are still present in treated plots than in controls. We will pursue this research to answer the following questions: (1) have the 2006 Ovenbirds suffered a higher mortality in treated plots than in controls? (2) If so, does immigration maintain the density of Ovenbirds in treated plots? (3) What is the approximate region from which these immigrants come from? (4) Does the reproductive success of the Brown Creeper and the Ovenbird fluctuate with the abundance of nest predators and, ultimately, in response to cycles in seed production? (5) Are these phenomena influenced by the harvest treatment? Neither of these bird species is currently rare but both are sensitive to forestry across their range. This research will thus provide information that will be critical to ensure that proactive conservation strategies are designed to maintain healthy populations of these and ecologically-similar species. Preventive research should receive as much attention as species recovery if we are to address the ultimate causes of biodiversity loss. So far, our work has influenced N.B. forest management policy, specifically to characterize forests of high conservation value.