Plant assemblage – substrate matching to inform nature-based solutions to coastal erosion

Coastal areas are high-energy, dynamic environments that are economically vital to the surrounding communities. However, these areas are increasingly threatened by climate change and anthropogenic pressures. In addition to engineering infrastructure for coastal protection, coastal vegetation implemented as a nature-based solution can play a significant role in protecting and buffering against coastal hazards. As a result of these pressures that coastal vegetation faces, many projects have emerged to restore these critical habitats. Coastal Newfoundland is highly influenced by human settlement and disturbance, with a landscape characterized by rocky coastlines and a mosaic of coniferous forests and coastal barrens with low-lying plants. Given that climate change is affecting coastal ecotones, one might also question whether these changing conditions favour the establishment of non-native species. We sampled 27 bays on the Island of Newfoundland, Canada, to explore the linkages between vegetation and the substrates on which it grows along cool-climate, boreal coasts. We used Non-metric Multidimensional Scaling (NMDS) to investigate the connection between vegetation species and substrates, and then employed generalized linear models to further examine the relationship between the amount of vegetation coverage on substrates and the presence of native versus non-native species. Our findings revealed that rocky sand and soil substrates have a higher vegetation coverage than the other substrates. Additionally, our models showed that native species are more frequently found on rocky and sandy substrates, while non-native vegetation species are more frequently found on soil substrates. These insights can guide decision-making processes when selecting vegetation for nature-based solutions aimed at protecting the coastal areas of the Avalon Peninsula.