Habitat and landscape associations of breeding birds in forested peatlands, Minnesota, USA.

Abstract

I compared breeding bird habitat use and community metrics among ten lowland conifer cover types in northern Minnesota. Breeding birds were sampled at 130 points distributed throughout black spruce, tamarack and white cedar forests within the Agassiz Lowland Subsection (ALS), Minnesota. Birds were sampled three times in the spring and summer of 2013 and twice during the spring and summer of 2014. I identified ten lowland conifer cover types using hierarchical clustering then identified distinctive breeding bird species of the ten lowland conifer cover types through indicator species analyses-percent perfect indication (PPI). Connecticut Warbler (Oporornis agilis) was most distinctive in semi-productive black spruce-tamarack bog cover types (PPI=40, P<0.01). Boreal Chickadee (Poecile hudsonicus) was most distinctive in productive black-spruce-tamarack bog cover types (PPI=8, p<0.01). Species such as the Nashville Warbler (Leiothlypis ruficapilla), Yellow-rumped Warbler (Setophaga coronata) and White-throated Sparrow (Zonotrichia albicollis) were ubiquitous across many lowland conifer cover types. The cluster analysis identified two bird communities that responded to differences in vegetation at the landscape level. Results from the Canonical Correspondence Analysis (CCA) showed significant relationships between breeding birds and vegetation variables (p<0.01). The results from the CCA ordination support the ten cover types identified from the hierarchical cluster analysis. These findings can inform forest and wildlife management decisions that will benefit the conservation and management of breeding birds in lowland conifer forests of the ALS. Disturbances such as logging, insect outbreaks, fire and climate change have the capacity to significantly alter bird communities within these lowland coniferous forests. Data presented here can improve our predictions of how the ALS avifauna will change given future changes to lowland conifer forests in the ALS.