Landscape‐scale greater prairie‐chicken–habitat relations and the Conservation Reserve Program

Abstract

Both the abundance of greater prairie‐chickens (Tympanuchus cupido pinnatus) and the area of grassland enrolled in the Conservation Reserve Program (CRP) in northwestern Minnesota, USA, have recently declined. Although wildlife conservation is a stated objective of the CRP, the impact of the CRP on greater prairie‐chicken populations has not been quantified. To address that information need, we evaluated the association between greater‐prairie chicken lek density (leks/km2), the number of males at leks (males/lek), and CRP enrollments in the context of landscape structure and composition in northwestern Minnesota. Using data from standardized prairie‐chicken surveys and land cover in 17 41‐km2 survey blocks during 2004–2016, we used a mixed‐effect model and a layered approach in an information‐theoretic framework at multiple spatial scales to identify covariates related to prairie‐chicken abundance. At the landscape scale, lek density was best explained by the amount of CRP grassland and wetland, grassland and wetland with long‐term conservation goals (state, federal, and The Nature Conservancy owned); other wetlands managed with variable or no continuity in conservation goals; the contiguity of grasslands; and the number of patches of grasslands and wetlands in each survey block each year. Increasing the amount of CRP grassland in 41‐km2 survey blocks by 1 km2 (2.4%) resulted in a corresponding increase of 6% in lek density. At the lek scale, the number of males per lek was best explained by the amount of CRP grassland and other grassland, CRP wetland and other wetland, forests, developed areas, shrubland, and the contiguity of CRP grassland. Increasing the amount of CRP grassland in the 2‐km breeding‐cycle habitat radius around a lek by 25% (3 km2) corresponded to a 5% increase in males per lek. Our results suggest that both increasing the quantity of grassland CRP and wetland CRP enrollments and aggregating CRP grassland enrollments may increase greater prairie‐chicken abundance. © 2019 The Wildlife Society.

Simulating Strategic Implementation of the CRP to Increase Greater Prairie‐Chicken Abundance

“…All covariates except the area of other wetlands and the number of grassland patches had a positive relationship with the abundance of greater prairie-chickens. The best-supported model of males/lek (log-transformed) at the lek scale included the percent areas CRP grasslands, grasslands with a long-term conservation focus (state-, federal-, and TNC-managed), CRP wetlands, wetlands managed with a long-term conservation focus (state-, federal-, and TNC-managed), other wetlands, forests, developed lands, shrublands, and the contiguity of grassland CRP (Adkins et al 2019). All covariates except the percent areas of other wetlands, forests, and developed lands had a positive relationship with the abundance of greater prairie-chickens.…”

“…We also considered the proportion of survey blocks or leks for which there were predicted increases in greater prairie-chicken abundance compared with predicted abundance under current conditions as an indication of an effect of CRP grasslands on greater prairie-chickens. We used FRAGSTATS (McGarigal et al 2012) to calculate the area of CRP grasslands, the area of CRP wetlands, the contiguity of grasslands, and the number of patches of grasslands and wetlands in each survey block for each land-cover scenario and used these measures to derive predictions of greater prairie-chicken abundance (leks/km 2 ) from the landscape-scale model of Adkins et al (2019). The area of grasslands and wetlands represented abundance of greater prairie-chicken habitat, contiguity represented the spatial distribution of habitat, and the number of patches of grasslands and wetlands represented fragmentation of habitat in our study areas.…”

“…We used these predicted landscapes to assess the effects of removing CRP enrollments on landscape composition, configuration, and fragmentation, and consequent effects on greater prairiechicken abundance. We modified the 2016 land-cover map by reclassifying expiring CRP enrollment areas to cropland and calculated leks/km 2 or males/lek and associated confidence intervals for expiration scenarios using the average normalized root mean square error (NRMSE) from the predictive models of Adkins et al (2019). CRP enrollments scenarios.-We evaluated 2 approaches to adding CRP enrollments to the landscape in northwestern Minnesota in the context of the core and corridor goals of the Minnesota Prairie Conservation Plan (MPCP; Minnesota Prairie Plan Working Group 2011): small (4,040 m 2 ) parcels added randomly and large (80,000 m 2 ) parcels added strategically to increase connectivity and decrease fragmentation as prescribed in the MPCP.…”

“…Predicted changes in the density of greater prairie-chicken males/lek, and land-cover metrics at the lek scale associated with Conservation Reserve Program (CRP) expiration scenarios and Minnesota Prairie Conservation Plan (MPCP) enrollment scenarios. Predicted changes are relative to the predictions based on cover-type composition present in 2016 and derived from the models of Adkins et al (2019). Land-cover metrics considered included percent combined CRP grasslands and wetlands and contiguity index of CRP grasslands at the lek scale in northwestern Minnesota, USA, 2004USA, -2016.…”

Multi-targeted management of upland game birds at the agroecosystem interface in midwestern North America

“…Breeding leks of prairie chicken have also increased as a direct result of the land-use characteristics most often promoted by CRP-lands (i.e., smaller residential-farmstead plots, reduced forest patches, and more expansive habitat parcels) [114]. Promoting an increase in the number of leks will also elevate the numbers of resident and competing males [115], an important consideration given the presence of dominant family groups [36]. Similarly, the retention of abundant grass and forb cover on CRP-fields also serves to promote nest survival in prairie chicken [116], a situation that similarly resonates with pheasant and quail.…”