Growth-survival trade-offs and the restoration of non-forested open ecosystems

Abstract

The growth-survival trade-off has been extensively documented for phanerophyte species, whereas there is little evidence for non-phanerophyte species. However, information on the growth-survival trade-offs in non-phanerophyte species could be of great use in non-forested open ecosystem restoration by providing insights for plant production and transplantation, thus impacting the planning of cost-effective restoration actions. In this study, we explored the relationship between growth and survival of individual plants of non-phanerophyte species used in a coastal dune restoration project, and we investigated whether plant functional traits explained patterns of trade-off between growth and survival. We monitored 355 individual plants of 13 perennial non-phanerophyte species belonging to foredune and transition dune communities every 30 days after planting and calculated relative growth and survival rates. In addition, we regressed the relationship between growth and survival on values of leaf and floral traits. We found that, besides being a widely recognised axis of life history variation in phanerophyte species, the growth-survival trade-off can also be observed in perennial non-phanerophyte species. Species of different coastal dune communities (i.e., foredune vs. transition dune communities) differed with respect to the growth-survival trade-off, with plant species of foredune communities exhibiting higher growth but lower survival rates than plant species of transition dune communities. Leaf dry matter content and mean number of floral displays explained species position on the growth-survival trade-off axis; species with relatively high growth and low survival rates exhibited an acquisitive strategy, with low values of leaf dry matter content, but also a low sexual reproductive effort, as revealed by low number of floral displays. In contrast, plant species with relatively low growth and high survival rates exhibited a conservative strategy but also high sexual reproductive effort, suggesting that trade-offs occur in resource allocation among vegetative and reproductive plant structures. The trade-off we found between growth and survival in perennial non-phanerophyte species provides useful insights for planning cost-effective ecosystem restoration actions of non-forested open ecosystems, especially when the actions are nature-based and involve planting individual plants. The results of this study suggest that individual plant production for coastal dune restoration should disproportionately target plant species of foredune communities because they have low survival rates associated with low sexual reproductive effort. Planning plant production based on ecological knowledge of plant species’ growth and survival after planting in the field could help achieve restoration goals while meeting project cost-effectiveness requirements.