Alien Invasions, Ecological Restoration in Cities and the Loss of Ecological Memory

TLDR

Ecological memory, comprising remnants such as soil properties, spores, and species, can guide post‑disturbance community assembly but is often weakened or mismatched in urban sites, necessitating directed restoration. The study calls for further research to document and conserve ecological memory to guide ecological restoration amid future ecosystem changes. Effective invasive species control requires addressing both within‑patch and between‑patch memory dynamics. Loss of ecological memory promotes invasive species establishment, which can then form a new stable domain with its own memory and resilience.

Abstract

Abstract After a community or ecosystem is lost, it may leave behind an ecological memory. The site history, soil properties, spores, seeds, stem fragments, mycorrhizae, species, populations, and other remnants may influence the composition of the replacement community or ecosystem to varying degrees. The remnants may also hold the site to a trajectory that has implications for ecological restoration. This is true in urban situations in particular where repeated disturbance has masked the history of the site. The ecological memory remaining may be insufficient for a site to heal itself; restoration activities are required to direct the future of the site. Conversely, in light of climate change and other rapidly changing environments, the existing ecological memory may be poorly suited to the new conditions and restoration projects need to create new and perhaps novel ecosystems. The loss of ecological memory facilitates the establishment of foreign invasive species. These invasives may eventually create a new stability domain with its own ecological memory and degree of resilience. To be successful, invasive species control must address both internal within patch memory of invasives and external between patch memory. Further research is necessary to document and conserve ecological memory for ecological restoration in response to future ecosystem changes.