Effect of road corridors on plant diversity in the Qionglai mountain range, China

Abstract

We analyzed the impact of mountain roads on patterns of species richness and community dissimilarity along elevation gradients with linear mixed-effects models, assessed how non-native/annual species modified these patterns of diversity, and explored changes in the effects of road on plant diversity along topographic gradients through the generalized additive model (GAM). Data analysis showed that (i) species richness for all, native and perennial species was unimodal relative to elevation and peaked at middle elevations; these patterns were modified by colonization of non-native and annual species favored by roads; (ii) mountain roads homogenized community compositions by selective extinction of native perennial species and to a lesser extent by colonization of annuals, rather than by colonization of non-native species; roads did not affect beta diversity response to elevation gradient; and (iii) mountain roads only contributed 8.98 % plant diversity at the landscape level; species richness was affected more by roads than by beta diversity. Montane ecosystems showed strong resilience to the influence of road the at landscape level. We suggest that new roads be planned and constructed on northeast-facing slopes and at lower elevations in order to minimize negative impacts on native plant diversity.

Keywords

• Mountain roads
• Beta diversity
• Biotic homogenization
• Native perennial species