Ecological impacts of invasive ecosystem engineers: A global perspective across terrestrial and aquatic systems

In both terrestrial and aquatic ecosystems, invasive species are a major driver of global change that is increasing in scope and impact due to the increase in global trade, habitat modification and climate change. Among invasive species, those that are known as ‘ecosystem engineers’ are considered a specific, highly influential, type of invaders, where an invader significantly alters the new environment, either physically or chemically. In this context, this perspective review discusses the different types of possible impacts of invasive ecosystems engineers (IEE) in terrestrial, freshwater, and marine ecosystems. Scanning the relevant literature on the topic, we find a 12-year lag in the use of terms relevant to the concept of ecosystem engineers in invasion-related publications since the first publication of the concept in 1994, with a steep increase in use between 2006 and 2014. A bibliometric mapping showed a high level of connectedness between related terms and clusters, suggesting an ample flow of concepts, ideas and knowledge between realms, ecosystems and regions, and researchers that study them. Throughout this essay, we illustrate with recent examples the context-dependency of their (positive and negative) impacts in the three realms. We review the distinction between autogenic (altering the environment for other species with their body) and allogenic (altering the environment for other species with their actions) ecosystem engineering in the context of alien species. We also put a spotlight on the well-studied engineering effects of IEE plants and macroalgae, terrestrial and aquatic bioturbators and burrowers as well as highly effective consumers. We finalize with discussing how IEE can strongly affect ecosystem services for human wellbeing and explore the possible contribution of IEE in restoring functions and services in the face of climate change in highly invaded and fast-warming systems like the southeastern Mediterranean Sea or areas that face frequent fires for example. We claim that the last topic has received little attention from the scientific community and should be given priority in future studies. Read the free Plain Language Summary for this article on the Journal blog.