Value of protected areas to avian persistence across 20 years of climate and land-use change.

Establishing protected areas, where human activities and land cover changes are restricted, is among the most widely used strategies for biodiversity conservation. This practice is based on the assumption that protected areas buffer species from processes that drive extinction. However, protected areas can maintain biodiversity in the face of climate change and subsequent shifts in distributions have been questioned. We evaluated the degree to which protected areas influenced colonization and extinction patterns of 97 avian species over 20 years in the northeastern United States. We fitted single-visit dynamic occupancy models to data from Breeding Bird Atlases to quantify the magnitude of the effect of drivers of local colonization and extinction (e.g., climate, land cover, and amount of protected area) in heterogeneous landscapes that varied in the amount of area under protection. Colonization and extinction probabilities improved as the amount of protected area increased, but these effects were conditional on landscape context and species characteristics. In this forest-dominated region, benefits of additional land protection were greatest when both forest cover in a grid square and amount of protected area in neighboring grid squares were low. Effects did not vary with species' migratory habit or conservation status. Increasing the amounts of land protection benefitted the range margins species but not the core range species. The greatest improvements in colonization and extinction rates accrued for forest birds relative to open-habitat or generalist species. Overall, protected areas stemmed extinction more than they promoted colonization. Our results indicate that land protection remains a viable conservation strategy despite changing habitat and climate, as protected areas both reduce the risk of local extinction and facilitate movement into new areas. Our findings suggest conservation in the face of climate change favors creation of new protected areas over enlarging existing ones as the optimal strategy to reduce extinction and provide stepping stones for the greatest number of species.

Valor de las Áreas Protegidas para la Persistencia de Aves a lo largo de 20 Años de Cambio Climático y Cambios en el Uso de Suelo Resumen El establecimiento de áreas protegidas, donde las actividades humanas y los cambios en la cobertura de suelo están restringidos, es una de las estrategias más utilizadas para la conservación de la biodiversidad. Esta práctica está basada en la suposición de que las áreas protegidas guarecen a las especies de los procesos que ocasionan la extinción. Sin embargo, se ha cuestionado si las áreas protegidas pueden mantener la biodiversidad de cara al cambio climático y los cambios subsecuentes en su distribución. Evaluamos el grado al cual las áreas protegidas influyeron sobre los patrones de colonización y extinción de 97 especies de aves durante 20 años en el noreste de los Estados Unidos. Ajustamos los modelos de ocupación dinámica de visita única a los datos de los Atlas de Aves Reproductoras para cuantificar la magnitud del efecto de los causantes de colonización y extinción local (p. ej.: clima, cobertura de suelo, tamaño del área protegida) en paisajes heterogéneos que variaron en cantidad de área bajo protección. Las probabilidades de colonización y extinción mejoraron conforme aumentó el tamaño del área protegida, pero estos efectos fueron condicionales con respecto al contexto del paisaje y a las características de la especie. En esta región dominada por bosques, los beneficios de una protección adicional del suelo fueron mayores cuando la cobertura de bosque en una cuadrícula y el tamaño del área protegida en una cuadrícula adyacente fueron bajos. Los efectos no variaron acorde a los hábitos migratorios o al estado de conservación de la especie. El aumento en la cantidad de suelo protegido benefició a las especies en los márgenes de su extensión pero no en la extensión nuclear de la especie. La mayores mejorías en la colonización y en las tasas de extinción se acumularon para las aves de bosque en relación con especies generalistas o de hábitat abierto. En general, las áreas protegidas frenaron la extinción más veces de las que promovieron la colonización. Nuestros resultados indican que la protección de suelo permanece como una estrategia viable de conservación a pesar del cambio que existe en los hábitats y en el clima ya que las áreas protegidas reducen el riesgo de extinción local y facilitan el movimiento hacia zonas nuevas. Nuestros hallazgos sugieren que la conservación de cara al cambio climático favorece la creación de nuevas áreas protegidas por encima del aumento de las ya existentes como la estrategia óptima para reducir la extinción y proporcionar escalones para el mayor número de especies.

Hindcasting the impacts of land-use changes on bird communities with species distribution models of Bird Atlas data.

Habitat loss and degradation induced by human development are among the major threats to biodiversity worldwide. In this study, we tested our ability to predict the response of bird communities (128 species) to land-use changes in southern Quebec (~483,100 km2 ) over the last 30 yr (between 1984-1989 and 2010-2014) by using species distribution models (299,302 occurrences in 30,408 locations) from a hindcasting perspective. Results were grouped by functional guilds to infer potential impacts on ecosystem services, and to relate model transferability (i.e., ability of our models to be generalized to other times and scales) to specific functional and life-history traits. Overall, our models were able to accurately predict, both in space and time, habitat suitability for 69% of species, especially for granivorous, nonmigrant, tree-nesting species, and species that are tied to agricultural areas under intensive use. These findings indicate that model transferability depends upon specific functional and life-history traits, providing further evidence that species' ecologies affect the ability of models to accurately predict bird distributions. Declining bird species were mostly short-distance migrants that were associated with open habitats (agricultural and nonproductive forest) with aerial insectivorous or granivorous diets, which may be related to agricultural intensification and land abandonment. Land-use changes were positive for some forest bird species that were mainly associated with mixed and deciduous forests, generalist diets and tree-nesting strategies. Yet cavity-nesting birds have suffered substantial reductions in their distributions, suggesting that cumulative effects of intensive logging and wildfires on mature forests pose a threat for forest-specialist species. Habitat suitability changes predicted by our coarse-scale species distribution models partially agreed with the long-term trends reported by the North American Breeding Bird Survey. Our findings confirm land-use change as a key driving force for shaping bird communities in southern Quebec, together with the need to explicitly incorporate it into global change scenarios that better inform decision-makers on conservation and management.

Spatial models to account for variation in observer effort in bird atlases.

To assess the importance of variation in observer effort between and within bird atlas projects and demonstrate the use of relatively simple conditional autoregressive (CAR) models for analyzing grid-based atlas data with varying effort. Pennsylvania and West Virginia, United States of America. We used varying proportions of randomly selected training data to assess whether variations in observer effort can be accounted for using CAR models and whether such models would still be useful for atlases with incomplete data. We then evaluated whether the application of these models influenced our assessment of distribution change between two atlas projects separated by twenty years (Pennsylvania), and tested our modeling methodology on a state bird atlas with incomplete coverage (West Virginia). Conditional Autoregressive models which included observer effort and landscape covariates were able to make robust predictions of species distributions in cases of sparse data coverage. Further, we found that CAR models without landscape covariates performed favorably. These models also account for variation in observer effort between atlas projects and can have a profound effect on the overall assessment of distribution change. Accounting for variation in observer effort in atlas projects is critically important. CAR models provide a useful modeling framework for accounting for variation in observer effort in bird atlas data because they are relatively simple to apply, and quick to run.