Access Type

Open Access Thesis

Date of Award

January 2013

Degree Type

Thesis

Degree Name

M.S.

Department

Biological Sciences

First Advisor

Daniel M. Kashian

Abstract

Grassland bird populations have declined across North America due to habitat loss but at a disproportionately higher rate in the midwestern United States, where extensive coverage of grasslands and other open land ecosystems have been converted to other land cover types. The upland sandpiper (Bartramia longicauda Bechstein, UPSA) is a migratory, area-sensitive, terrestrial shorebird that breeds in grasslands and other open land ecosystem types across their North American range. Although breeding habitats of the Great Plains contain the greatest concentrations of this species, anthropogenic openings such as hayfields and pastures serve as surrogate habitat elsewhere, as do remnant patches of native open land ecosystems that are less understood as UPSA habitats. The upland sandpiper may therefore represent a flagship species for restoration of native open land ecosystems and a novel conservation opportunity within human-maintained open land cover types. A dearth of information about UPSA habitat selection and use in Michigan (a state of decided importance for UPSA habitat east of the Mississippi River) and elsewhere in the eastern United States forces a reliance on data from studies conducted in other areas of the species' range for conservation and management efforts. I used two Michigan Breeding Bird Atlases (1983 to 1988 and 2002 to 2008) to compare areas where (1) breeding UPSA persisted for both Atlas periods (long-term occupied habitat); (2) breeding UPSA were present only in the first Atlas period (short-term occupied habitat); and (3) areas where UPSA was never located during the two sampling periods. Analyses were conducted at the scale of Atlas blocks (4.8 km2 blocks defined by the Michigan Breeding Bird Atlas), the largest openings in those Atlas blocks (ranging in size from 17 to 2225 ha), and 39 field sites. At the broadest scale, long-term and short-term occupied UPSA habitat were more commonly located in the northern Lower Peninsula of Michigan (NLP), typically on coarse-textured soils; random Atlas blocks in the southern Lower Peninsula (SLP) where UPSA was not present were more often located on fine-textured soils. These soils are typically associated with row crops and other intensively managed agricultural land covers. At the scale of openings within the Atlas blocks, openings containing long-term occupied habitat tended to be located within agricultural areas dominated by forage crops managed at a relatively low intensity (non-tilled) such as hayland and pasture; short-term occupied habitat tended to be in herbaceous open lands; and non-occupied open lands in the SLP were dominated by row crops. Field sampling in occupied patches in northern Michigan confirmed that UPSA use a wide range of open land cover types as breeding habitat, excluding row crops, even when woody plant coverage approached 50%. The location of short-term occupied habitat in xeric, sandy, fire-dependent ecosystems suggests a much more dynamic system compared to the more stable, human-maintained forage crops (pastures and hayfields) that characterize a larger proportion of long-term occupied habitat. UPSA habitat in Michigan therefore appears to depend more on human-associated cover types, which persist longer and change less than natural cover types in the absence of fire in this region. However, considerable opportunities exist for management of the more dynamic (short-term) habitats as a disproportionate area containing these ecosystem types are under public ownership. As such, conservation planning and management for UPSA in Michigan depends more strongly upon on understanding the long-term stability of cover types forming habitat rather than simply their differences in vegetation structure or composition.

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