Delineating Grassland Bird Conservation Areas in the U.S. Prairie Pothole Region

Abstract

Conservation of birds is increasingly focused on the importance of landscape characteristics to sustain populations. Implementing conservation on a landscape scale requires reliable spatial models that provide biological context for conservation actions. Before species-specific models relating grassland birds to their habitat at landscape scales existed, we created a conceptual model and applied it to spatial data to identify priority grassland habitats for the protection and restoration of populations of area sensitive grassland birds in the Prairie Pothole Region. Since that time, these Grassland Bird Conservation Areas have been widely used to guide conservation, and variations of these models have been adopted in other regions; however, the process used to delineate them (i.e., the conceptual models) is poorly understood by many users. We describe that process here and offer perspectives on the utility and limitations of conceptual models, especially on the value of making assumptions that commonly underlie management decisions explicitly, thereby making the assumptions testable, and hopefully increasing management transparency, credibility, and efficiency.

Do natural areas in urban landscapes support successful reproduction by a group of conservation priority birds?

“…Across North America, grassland bird populations have declined steadily for several decades primarily because of loss and fragmentation of grassland habitat (Herkert, 1995;Sauer et al, 2009). To curtail these declines, conservation efforts have focused on protecting large core grassland patches surrounded by a matrix with substantial grassland cover and minimal woody vegetation and urban land cover (Sample & Mossman, 1997;Johnson et al, 2010). These principles have been conceptually formalized under the 'grassland bird conservation area' (BCA) model (Sample & Mossman, 1997).…”

“…However, these studies of reproductive success have concentrated on agricultural or forested landscapes, with no studies examining landscapes with significant amounts of urban land cover. While the BCA model assumes urban land cover to be a hostile matrix to grassland birds and habitat located in urban landscapes is assumed to be of poor quality (Johnson et al, 2010), this assumption remains untested and may wrongly depreciate the value of habitat in urban landscapes.…”

Quantifying avian relative abundance and ecosystem service value to identify conservation opportunities in the Midwestern U.S.

“…We classified patches of suitable habitat into GBCAs using criteria modified from Johnson et al (2010). Classifications were based on patch size and proportion of grassland cover in the matrix surrounding the patch (Table 3).…”

“…Core patches and their surrounding matrix can be thought of as conservation or management units, for example, when a core is a protected area. GBCAs have been identified in the Prairie Pothole Region of the U.S. (Johnson et al 2010), and in the states of Missouri and Iowa (Jacobs et al 2005(Jacobs et al , 2012. Surprisingly, bird observations are not used to identify or rank GBCAs because the identification process occurs at scales larger than available observational data.…”

“…Grassland bird conservation has included the protection of large tracts and complexes of grassland habitat referred to as Grassland Bird Conservation Areas (GBCAs; e.g., Johnson et al 2010). This framework was developed to prioritize conservation given the sensitivity of many grassland birds to habitat fragmentation (Herkert 1994, Herkert et al 2003, but see Benson et al 2013), but GBCA designation does not by itself equate with any level of protection.…”