A multi-model approach to guide habitat conservation and restoration for the endangered San Bernardino kangaroo rat

The San Bernardino kangaroo rat (Dipodomys merriami parvus) is a federally listed endangered species endemic to Southern California and limited to three remaining populations. Its native habitat of alluvial fan sage scrub faces many anthropogenic threats, including urban and agricultural development, and the resulting flood control and fire suppression. With the loss of natural processes such as scouring or burning from floods and fires, the mosaic of seral stages across the landscape has shifted to dense vegetation, and active restoration may be necessary to provide suitable habitat for the San Bernardino kangaroo rat. Species distribution modeling using the partitioned Mahalanobis distance method on all occurrence points collected in the past 16 years revealed that alluvial scrub cover and fluvent soils were most strongly associated with San Bernardino kangaroo rat occupancy. Through surveys at 14 locations across the species’ range, we identified non-native grass cover, shrub cover, bare ground and sandy soils as microhabitat features related to San Bernardino kangaroo rat abundance. We also calculated the optimal range of cover for each habitat type that was correlated with higher kangaroo rat abundance. The results of this multiple-model approach can be used by the agencies to assess the value of conserved habitat, set targets for microhabitat enhancement to facilitate population growth and expansion, or identify receiver sites should translocation be required for recovery. This work lays the foundation for more coordinated and strategic restoration efforts, given the compressed and rigid timelines of development projects that continue to impact remaining San Bernardino kangaroo rat populations.