Surveys along unpaved roads can be a valuable, unbiased source of information for species distribution models

Predicting Species Distributions from Samples Collected along Roadsides

KYLE P. MCCARTHY, ROBERT J. FLETCHER JR,CHRISTOPHER T. ROTA and RICHARD L. HUTTO

Conservation Biology

Volume 26, Issue 1, pages 68–77, February 2012

Currently we do not know whether roadside sampling limits the accuracy of predictions generated by species distribution models. The researchers here tested whether roadside sampling affects the accuracy of predictions generated by species distribution models by using a prospective sampling strategy designed specifically to address this issue. They built models from roadside data and validated model predictions at paired locations on unpaved roads and 200 m away from roads, spatially and temporally independent from the data used for model building.

 The researchers predicted species distributions of 15 bird species on the basis of point-count data from a landbird monitoring program in Montana and Idaho (U.S.A.). They used hierarchical occupancy models to account for imperfect detection. The researchers expected predictions of species distributions derived from roadside-sampling data would be less accurate when validated with data from off-road sampling than when it was validated with data from roadside sampling and that model accuracy would be differentially affected by whether species were generalists, associated with edges, or associated with interior forest. Model performance measures (kappa, area under the curve of a receiver operating characteristic plot, and true skill statistic) did not differ between model predictions of roadside and off-road distributions of species. Performance measures did not differ among edge, generalist, and interior species, despite a difference in vegetation structure along roadsides and off road.  2 of the 15 species were found more likely to occur along roadsides.

The researchers contend that surveys along unpaved roads can be a valuable, unbiased source of information for species distribution models.