Road-class composition and the spatial scaling of ecological asynchrony

This is the authors' abstract. We don't add key points for this paper.

Road density and road-class composition describe different aspects of infrastructure, but their associations with ecological scaling remain unclear. We examined these associations across 78 biodiversity–stability scaling units: 31 US NEON plant sites and 47 RivFishTIME fish basins, including 43 in Europe. A multiscale main-road share index summarized the relative contribution of GRIP highways and primary roads to total road density. In the core richness-adjusted model, the index was negatively associated with asynchrony–area scaling (zAsAR; standardized coefficient, −0.240). The 95% interval after first-stage uncertainty propagation was −0.483 to −0.002, and the three-response Holm P value was 0.1464. The coefficient remained negative after adjustment for measured total road density, although statistical support varied across model specifications and multiplicity adjustments. Within the identity zEStAR = zSStAR + zAsAR, the positive species-stability coefficient partly offset the negative asynchrony coefficient; both species-stability and total-stability associations were uncertain. Separate-system estimates were more negative for plants, but both intervals and their difference spanned zero. Individual units influenced the pooled coefficient's magnitude and precision. Road-class composition may help describe variation in asynchrony scaling, although the available evidence is limited and geographically uneven. The index measures composition, and temporal mismatch between road layers and biological records prevents inference about ecological responses to road construction.