PS 8-74
Characterization and prediction of future habitat suitability for three bird species inhabiting the Rio Grande Bosque, NM
Future expected changes in climate and human activity threaten many riparian habitats, particularly in the southwestern US. As part of an ongoing project to assess future climate, fire and hydrological change for riparian species along the Rio Grande, New Mexico, we report the results of an ecological niche model analysis for three bird species. Our objective was to identify important areas for conservation efforts given future changes in distribution and availability of suitable habitat. Using Maximum Entropy (MaxEnt3.3.3) modeling, we characterized habitat relationships and generated spatial predictions of habitat suitability for Lucy’s warbler (Oreothlypis luciae), the Southwestern willow flycatcher (Empidonax traillii extimus) and yellow-billed cuckoo (Coccyzus americanus). Observation data came from museum collections as well as surveys conducted by RMRS. We downloaded current and future (2060) climate and habitat variables from three recent analyses: Bureau of Reclamation’s CMIP3 Climate and Hydrology Projections, Rehfeldt et al. 2006, and Notaro et al. 2012. Future conditions were based on climate models run under an A2 scenario. We ran 5000 iterations to optimize each model, used crossvalidation to test model fit and compared spatial bias correction and regularization techniques on model performance. We used jackknife resampling to estimate relative importance of individual variables.
Results/Conclusions
The models performed well in predicting summer habitat and we found proximity to water was an important variable for all three bird species. For the yellow-billed cuckoo, elevation, potential evapotranspiration, and precipitation during the warmest quarter were also important indicators for suitable habitat. For the Southwestern willow flycatcher, slope, biome, and mean diurnal temperature range were important and for Lucy’s warbler, elevation, mean diurnal range of temperature, and maximum temperature in July were important predictors. By 2060, all species are likely to experience reductions in availability of suitable habitat. Suitable habitat is predicted to occur in areas further north and at higher elevations and becomes more dispersed across the landscape. Future locations of suitable habitat shift across ownership boundaries and highlight potential foci for restoration and conservation. The presence of non-climate indicator variables also points to important management considerations. This study provides an example of a presence-only habitat model that can be used to inform the management of species that are expected to lose a great deal of habitat under climate change. These habitat models can also be combined with other assessment methods to more fully understand the range of potential impacts for species under changing climate.