The role of seed banks in coastal plant community response to climate change: Implications for restoring ecosystem resiliency.

摘要

Accelerated sea-level rise and increased intensity of tropical storm events have challenged the conventional approaches to conservation and restoration of coastal ecosystems. In coastal communities, where survival will depend largely on the ability of species to adapt to rapidly shifting conditions or become established farther inland, historic assemblages may be lost. Seed banks may be an important component of resilience and recovery in response to altered inundation regimes, should they contain species able to adapt or migrate inland. This study assess the ability of seed banks to act as ecological buffers to storm surge disturbances and to instill ecological resilience in degraded and vulnerable coastal ecosystems. Above-ground, seed bank and propagule assemblages were surveyed from historic communities at the Grand Bay National Estuarine Research Reserve. Artificial storm surge experiments revealed that that seed banks were not well distributed throughout the coastal transition communities and that seed bank responses following storm surges are likely to vary among the different plant communities. While some relict species are expected to respond following disturbances, ruderal species are especially dominant in the upland seed bank communities and may, at least in the short term, cause shifts away from the historical assemblages. The apparent absence of seaward species in the upland seed banks may make assisted migration an important tool for the survival of communities unable to keep pace. Community response following translocation of propagule bank application onto highly degraded buyout properties suggested that this technique may be an effective tool in introducing resilience into ecosystems already experiencing the effects of climate change. They resulted in the establishment of diverse and variable communities, containing indicator species from a number of historic communities with varying environmental tolerances. Long-term monitoring of community change and reproductive output of target species may indicate the utility of community translocation in creating resilient and future-adapted communities.