TPOS notes:
This study of habitat use by the rare Henslow's sparrow in eastern Kansas sampled grassland sites in the fragmented agricultural landscape ("Western Corn Belt Plains" ecoregion) as well as the extensive remnant grasslands of the Flint Hills. The species avoided woody vegetation and cropland, preferring landscapes with a higher proportion of grassland; for example, individuals were more likely to be detected in smalll patches of CRP embedded in rangeland than small patches of CRP surrounded by agricultural land. However, even in the Flint Hills the sparrows occupied less than 4% of the grassland area preferring CRP to intensively managed rangeland (typically grazed or burned then grazed). By using multiple sampling periods, researchers found that the sparrows were highly mobile within any given year, and in some cases occupied sites after mid-June that had been burned earlier in the year, though none were detected at completely burned sites during early season sampling.
First online 10/5/17 in Landscape Ecology.
Authors
Mark R. Herse, Michael E. Estey, Pamela J. Moore, Brett K. Sandercock, W. Alice Boyle
Abstract
Purpose
Wildlife conservation requires understanding how landscape context influences habitat selection at spatial scales broader than the territory or habitat patch.
Objectives
We assessed how landscape composition, fragmentation, and disturbance affected occurrence and within-season site-fidelity of a declining grassland songbird species (Henslow’s Sparrow, Ammodramus henslowii).
Methods
Our study area encompassed eastern Kansas (USA) and North America’s largest remaining tracts of tallgrass prairie. We conducted 10,292 breeding-season point-count surveys over 2 years, and related occurrence and within-season site-occupancy dynamics of sparrows to landscape attributes within 400-, 800-, and 1600-m radii.
Results
Sparrows inhabited < 1% of sites, appearing and disappearing locally within and between breeding seasons. Early in spring, sparrows responded to landscape attributes most strongly within 400-m radii, settling in areas containing > 50% unburned prairie. Later in summer, sparrows responded to landscape attributes most strongly within 800-m radii, settling in areas containing > 50% unfragmented prairie, including sites burned earlier the same year. Sparrows avoided landscapes containing woody vegetation, disappeared from hayfields after mowing, and were most likely to inhabit landscapes containing Conservation Reserve Program (CRP) fields embedded within rangeland.
Conclusions
Landscape context influenced habitat selection at spatial scales broader than both the territory and habitat patch. Protecting contiguous prairies from agricultural conversion and woody encroachment, promoting CRP enrollment, and maintaining portions of undisturbed prairie in working rangelands each year are critical to reversing the conservation crisis in North America’s remaining grasslands. As landscape change alters natural areas worldwide, effective conservation requires suitable conditions for threatened species at multiple spatial scales.
Citation
Herse, M.R., Estey, M.E., Moore, P.J. et al. Landscape Ecol (2017). https://doi.org/10.1007/s10980-017-0574-z
Friday, November 3, 2017 at 1:00PM