Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

• Main Authors: Charalampos Dimitriadis, Ivoni Fournari–Konstantinidou, Laurent Sourbès, Drosos Koutsoubas, Stelios Katsanevakis
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Diversity
• Subjects: alien species; herbivores; niche theory; marine protected areas
• Online Access: https://www.mdpi.com/1424-2818/13/2/71

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.