R E S E A R C H A R T I C L E ABSTRACT: In support of natural resource agencies in Canada, the United States, and Mexico, we report on a series of component analyses and an updated Landscape Conservation Design for temperate • grassland conservation. We targeted 12 major grassland ecosystem types that occur across the Great Plains and Chihuahuan Desert regions. Component analyses included (1) documenting long-term trends in extent by grassland type, (2) identifying species of concern associated with the major grassland types, Continent- (3) documenting current protected areas including each grassland type, (4) assessing landscape intactness and connectivity among grassland areas, and (5) identifying Grassland Potential Conservation Areas Scale Landscape (GPCAs) to advance grassland conservation. Most severe declines in grassland extent have occurred in tallgrass prairie types, followed by mixed-grass, shortgrass, and semi-desert grasslands. Similar trends Conservation by type were documented for landscape intactness and connectivity. Some 174 species of vertebrates, invertebrates, and plants considered by NatureServe as critically imperiled, imperiled, or vulnerable are Design for strongly associated with these grassland types, and 103 are listed under protective legislation in one or more countries. Just 1.2% of historic extent for all types combined is currently found within designated Temperate protected areas. A total of 177 GPCAs were identified to represent grassland type diversity in areas least likely to conflict with other land uses. Within identified GPCAs, type-specific representation varied from Grasslands of the a low of just 1% of historic extent for Texas Blackland Tallgrass Prairie to a high of 27% for Western Great Plains and Great Plains Sand Prairie. Combined across all 12 grassland types, 15% of historic extent is represented. Chihuahuan Desert Index terms: Aichi Target 11, conservation land investments, Landscape Conservation Design, long-term trends in extent, temperate grassland types Patrick J. Comer1,5 INTRODUCTION the Great Plains to Mexico’s Chihuahuan 1Ecology Department Desert grasslands have declined by almost NatureServe Due to land use intensification (Hoekstra 70% since 1970. Among the diverse her- 1680 38th Street Suite 120 et al. 2005) and projected impacts of cli- bivores of the grasslands, the black-tailed Boulder, CO 80301 mate change (Sala et al. 2000), temperate prairie dog (Cynomys ludovicianus Ord), grasslands are considered among the most often considered a “keystone” species in Jon C. Hak1 threatened biomes worldwide. North Amer- these grasslands, has experienced dramatic 2 Kelly Kindscher ican prairies and desert grasslands have population decline due to multiple factors Esteban Muldavin3 sustained extensive loss to land conversion including use of poison, habitat conversion, and degradation since the 1800s due to and sylvatic plague, and was recently con- Jason Singhurst4 agricultural conversion, overgrazing, and sidered for listing under the Endangered infrastructure development (Buffington and Species Act (Hoogland 2013). 2Kansas Biological Survey Herbel 1965). Those grasslands, extending University of Kansas from the Canadian prairie provinces of Regional patterns in climate (from cool and 2101 Constant Avenue Manitoba, Saskatchewan, and Alberta, moist to hot and dry) and soils explain much Lawrence, KS 66047 south across the US Great Plains and of the natural variation in major temperate through the Chihuahuan Desert of Northern grassland types. Tallgrass prairies occur 3Natural Heritage New Mexico Mexico, have experienced similar declines in a north–south belt from Manitoba to Biology Department to others found worldwide. Significant east Texas. Mixed-grass prairies dominate MSC03 2020 1 University of New portions of the vast trinational area (3M the Canadian prairies, extending south Mexico km2) are considered a “breadbasket of the throughout the central Great Plains to Albuquerque, NM 87131 world” with some of the most productive central Texas. Both shortgrass and sand and intensively cultivated croplands and prairies, occurring on loamy and sandy 4Texas Parks and Wildlife Department pasture lands (Gauthier et al. 2003). soils, respectively, predominate the west- 4200 Smith School Road ern and southern Great Plains. Finally, Austin, TX 78744 Wildlife has paid a steep price for this semi-desert grasslands occur throughout agricultural output. Grassland birds have the Chihuahuan Desert in southern Arizona, seen sharp declines with increasingly frag- New Mexico, and west Texas, and extend • mented and converted habitat (With et al. south and east to San Luis Potosí and 2008; Hill et al. 2014), as have many other Nuevo León, Mexico (Figure 1). 5 Corresponding author: grassland-dependent plants and animals. [email protected]; (703) 797- For example, the grassland avian commu- Patterns in habitat loss vary among grass- 4802 nity is among the highest conservation con- lands and are also related to climate and Natural Areas Journal 38:196–211 cern due to rapidly declining populations soils, which influence agricultural poten- (NABCI 2016). Species that migrate from tial. By combining agricultural potential 196 Natural Areas Journal Volume 38 (2), 2018 Figure 1. Approximate historical extent of 12 major temperate grassland types. Volume 38 (2), 2018 Natural Areas Journal 197 with distribution of infrastructure and intact habitat, establishing redundancy Gap Analysis Program (https://gapanalysis. access to markets, one can identify major where needed, ensuring fine-scale and usgs.gov/gaplandcover/; see type descrip- trends of grassland conversion over the past broad-scale connectivity for species and tions at http://explorer.natureserve.org/). century. More recent trends in agricultural processes, providing refugia for species Recent investments in continental-scale intensification of the Chihuahuan Desert from rapid landscape change, and restoring mapping have identified 12 major grassland (Pool et al. 2014), biofuel production targeted habitats and species. The project types across this trinational area. (Wright and Wimberly 2013), and energy was designed to demonstrate the capacity development (Pruitt et al. 2009; Fargione of available data and analytical tools and Within the United States, LANDFIRE has et al. 2012) have introduced pockets of approaches to identify priority conservation produced map products for “biophysical rapid change across the region (Drummond areas to focus individual decisions and setting” of major upland ecological system et al. 2012). conservation investments by agencies, and type—effectively an estimate of potential/ potential coordinated efforts. Below we historical location and extent—using in- Prevailing patterns of land ownership shape report on a series of component analyses ductive modeling that utilizes field-based conservation priorities and actions in these leading to an updated Landscape Conser- observations of each type and correlates temperate grasslands. Privately held lands vation Design (LCD) identifying Grassland these with mapped information on cli- prevail throughout the Canadian and US Potential Conservation Areas (GPCAs) as mate, landform, and soil (Rollins 2009). prairies, while communal land ownership focal areas for conservation action. NatureServe then applied the same meth- is more frequently encountered in Mexico. ods with data extending across temperate Private ownership predominates where Component analyses included: Canada and south across Mexico (Comer agricultural productivity remains high, and (a) documenting long-term trends in extent et al. unpub. data) to provide a complete so historic triggers for concentrated public of 12 major temperate grassland types; distribution for each major grassland type ownership (e.g., tax-reversion of lands (b) identifying species of concern associ- at spatial resolutions of approximately 5-ha during the Great Depression) were limited ated with the major grassland types; minimum map unit. Using these estimates to shortgrass prairie and desert grasslands (c) documenting current protected areas of historical extent, the 12 most extensive (Gauthier et al. 2003; Samson et al. 2004). including each grassland type; grassland types were identified and served Given these ownership patterns, conserva- (d) assessing landscape intactness and as the focus for this analysis. Figure 1 tion largely takes place on lands controlled connectivity among grassland areas; and depicts predicted historical extent of each by private individuals, corporations, or (e) complete landscape conservation of the 12 major temperate grassland types. communal land stewards. Consequently, a design to identify GPCAs to advance These grassland types range in estimated mix of public land acquisition, government grassland resiliency. historical extent from a high of nearly subsidies for private conservation action, 630,000 km2 for Northwest Great Plains conservation easements, and multi-stake- Brief summaries of methods and results are Mixed-grass Prairie, occurring from Ne- holder partnerships (Gauthier et al. 2003; provided with each component analysis. braska north across southeastern Alberta, to Drum et al. 2015) may be important for a low of 8100 km2 for Chihuahuan Sandy addressing pervasive and critical threats to Plains Semi-Desert Grassland occurring in these grasslands, and to achieving desired TRENDS IN EXTENT OF MAJOR cross border region of Texas, New Mexico, conservation outcomes. GRASSLAND TYPES and