Landscape-scale conservation mitigates the biodiversity loss of grassland birds.

The decline of biodiversity from anthropogenic landscape modification is among the most pressing conservation problems worldwide. In North America, long-term population declines have elevated the recovery of the grassland avifauna to among the highest conservationpriorities. Because the vast majority of grasslands of the Great Plains are privately owned, the recovery of these ecosystems and bird populations within them depend on landscape-scale conservation strategies that integrate social, economic, and biodiversity objectives. The Conservation Reserve Program (CRP) is a voluntary program for private agricultural producers administered by the United States Department of Agriculture that provides financial incentives to take cropland out of production and restore perennial grassland. We investigated spatial patterns of grassland availability and restoration to inform landscape-scale conservation for a comprehensive community of grassland birds in the Great Plains. The research objectives were to (1) determine how apparent habitat loss has affected spatial patterns of grassland bird biodiversity, (2) evaluate the effectiveness of CRP for offsetting the biodiversity declines of grassland birds, and (3) develop spatially explicit predictions to estimate the biodiversity benefit of adding CRP to landscapes impacted by habitat loss. We used the Integrated Monitoring in Bird Conservation Regions program to evaluate hypotheses for the effects of habitat loss and restoration on both the occupancy and species richness of grassland specialists within a continuum-modeling framework. We found the odds of community occupancy declined by 37% for every 1 SD decrease in grassland availability [loge (km2 )] and increased by 20% for every 1 SD increase in CRP land cover [loge (km2 )]. There was 17% turnover in species composition between intact grasslands and CRP landscapes, suggesting that grasslands restored by CRP retained considerable, but incomplete, representation of biodiversity in agricultural landscapes. Spatially explicit predictions indicated that absolute conservation outcomes were greatest at high latitudes in regions with high biodiversity, whereas the relative outcomes were greater at low latitudes in highly modified landscapes. By evaluating community-wide responses to landscape modification and CRP restoration at bioregional scales, our study fills key information gaps for developing collaborative strategies, and for balancing conservation of avian biodiversity and social well-being in the agricultural production landscapes of the Great Plains.

Scaling up private land conservation to meet recovery goals for grassland birds.

Long-term population declines have elevated recovery of grassland avifauna to among the highest conservation priorities in North America. Because most of the Great Plains is privately owned, recovery of grassland bird populations depends on voluntary conservation with strong partnerships between private landowners and resource professionals. Despite large areas enrolled in voluntary practices through U.S. Department of Agriculture's Lesser Prairie-chicken (Tympanuchus pallidicinctus) Initiative (LPCI), the effectiveness of Farm Bill investments for meeting wildlife conservation goals remains an open question. Our objectives were to evaluate extents to which Conservation Reserve Program (CRP) and LPCI-grazing practices influence population densities of grassland birds; estimate relative contributions of practices to regional bird populations; and evaluate percentages of populations conserved relative to vulnerability of species. We designed a large-scale impact-reference study and used the Integrated Monitoring in Bird Conservation Regions program to evaluate bird population targets of the Playa Lakes Joint Venture. We used point transect distance sampling to estimate density and population size for 35 species of grassland birds on private lands enrolled in native or introduced CRP plantings and LPCI-prescribed grazing. Treatment effects indicated CRP plantings increased densities of three grassland obligates vulnerable to habitat loss, and LPCI grazing increased densities of four species requiring heterogeneity in dense, tall-grass structure (α = 0.1). Population estimates in 2016 indicated the practices conserved breeding habitat for 4.5 million birds (90% CI: 4.0-5.1), and increased population sizes of 16 species , totaling 1.8 million birds (CI: 1.4-2.4). Conservation practices on private land benefited the most vulnerable grassland obligate species (AICc weight = 0.53). By addressing habitat loss and degradation in agricultural landscapes, conservation on private land provides a solution to declining avifauna of North America and scales up to meet population recovery goals for the most imperiled grassland birds.

Ampliación de la Conservación en Terrenos Privados para Cumplir los Objetivos de Recuperación para Aves de Pastizales Resumen La declinación a largo plazo de las poblaciones ha posicionado a la recuperación de la avifauna de los pastizales entre las prioridades de conservación más importantes en América del Norte. Debido a que la mayor parte de las Grandes Planicies es propiedad privada, la recuperación de las poblaciones de aves de los pastizales depende de la conservación voluntaria sumada a la colaboración entre los terratenientes privados y los profesionales de la gestión de recursos. A pesar de que varias áreas se encuentran inscritas en prácticas voluntarias por medio de la Iniciativa de la Gallina de Pradera Menor (Tympanuchus pallidicinctus) (IGPM), la efectividad de la inversión del Proyecto de Ley de Granjas para cumplir con los objetivos de conservación de fauna todavía permanece como una pregunta abierta. Nuestros objetivos se enfocaron en evaluar hasta qué punto el Programa de Reservas de Conservación (PRC) y las prácticas de forrajeo de la IGPM influyen sobre la densidad poblacional de las aves de los pastizales; estimar las contribuciones relativas de las prácticas para las poblaciones de aves regionales; y evaluar el porcentaje de poblaciones conservadas en relación con la vulnerabilidad de la especie. Diseñamos un estudio a gran escala con referencia de impactos y usamos el programa de Monitoreo Integrado en las Regiones de Conservación de Aves para evaluar los objetivos poblacionales de las aves del Proyecto Conjunto de Playa Lakes. Usamos un muestreo de distancia por puntos en transecto para estimar la densidad y el tamaño poblacional de 35 especies de aves de pastizales en los terrenos privados inscritos en plantaciones nativas o introducidas del PRC y en las zonas de forrajeo prescritas por la IGPM. Los efectos del tratamiento indicaron que las plantaciones del PRC incrementaron la densidad de tres especies estrictas de pastizales vulnerables a la pérdida del hábitat, mientras que el forrajeo de la LPCI incrementó la densidad de cuatro especies que requieren heterogeneidad en la estructura de pastos altos y gruesos (α = 0.1). Las estimaciones poblacionales indicaron que las prácticas conservaron el hábitat de reproducción para 4.5 millones de aves (90% IC 4.0 - 5.1) e incrementaron el tamaño poblacional de 16 especies, para un total de 1.8 millones de aves (IC 1.4 - 2.4). Las prácticas de conservación en terrenos privados beneficiaron a las especies estrictas de pastizales más vulnerables (peso AICc = 0.53). Al abordar la pérdida y degradación del hábitat en los paisajes agrícolas, la conservación en terrenos privados proporciona una solución para la avifauna en declinación de América del Norte y se amplía para cumplir con los objetivos de recuperación establecidos para las aves de pastizales que se encuentran en mayor peligro.