Blurring the lines between production and conservation lands: Bird use of prairie strips in row-cropped landscapes

Abstract

The widespread conversion of native ecosystems to row crops in the Midwestern United States has led to phenomenal agricultural productivity. However, agricultural intensification has also caused declines in soil and water quality, and losses in native biodiversity. Establishing perennial vegetation in crop-dominated landscapes has been shown to improve ecosystem functioning and expand the suite of ecosystem services provided by agricultural landscapes. Incorporating perennial vegetation can also provide habitat that is lacking in row-cropped landscapes. Given most agricultural lands are privately owned, and landowners’ dependence on farm income, it may not be feasible to transform large areas of row crops to perennials. Thus, in 2007, the STRIPs at Neal Smith National Wildlife Refuge project team initiated an experiment to test the hypothesis that interjecting small amounts of diverse prairie at key locations within agricultural landscapes will produce disproportionate improvements in ecosystem functioning and biodiversity. While the overall STRIPs experiment addresses several aspects of ecosystem functioning and ecosystem service delivery, the study presented here evaluates how birds respond to small amounts of prairie integrated into row crops. Bird response was measured in terms of total bird abundance, species richness, and diversity. I derived these measurements from surveys of breeding birds in 15 small experimental watersheds (0.5-3.2ha) with five treatments of varying percentages (0%, 10%, 20%, and 100%) and configurations of row-crop and prairie cover. The results indicate that birds respond positively to the establishment of small prairie strips within row-crop fields; the data demonstrate large shifts in abundance, species richness and diversity from 0% prairie treatments to 10-20% prairie treatments, and from the planting year to post-establishment years. Across the six years of study (2007-2012), we observed a total of 52 species using the experimental sites; 16 species comprised 99% of the observations, including many generalist species and some species of greatest conservation need. Red-winged Blackbird, Common Yellowthroat, American Goldfinch, Dickcissel, Field Sparrow, and Brown-headed Cowbird were the most common species observed across all years. We documented nesting for 11 species. Total bird abundance, species richness, and Simpson’s diversity were all significantly higher in experimental treatments containing prairie than in the entirely cropped treatment. Year and experimental block also had significant effects on the bird response. This experiment demonstrates that prairie strips incorporated into row crops have the potential to provide habitat for birds, including some species of conservation concern.