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

Abstract

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.

Screening for Hyperthermophilic Electrotrophs for the Microbial Electrosynthesis of Organic Compounds

“…The temporal variation of impacts was not taken into account. Still, invasive alien species can regress after an invasion phase, following a so-called "boom and bust" invasion pattern, as has been reported for Caulerpa cylindracea, C. taxifolia, L. lallemandii and S. schimperi (Iveša et al 2006;Montefalcone et al 2015;Dimitriadis et al 2021;Santamaría 2021). Unfortunately, the literature of marine invasions sorely lacks scientific articles showing the evolution of invaded sites over several decades (Strayer et al 2017;Ojaveer et al 2018).…”

Prvi nalaz tupousne barakude Sphyraena chrysotaenia (Klunzinger, 1884.) i indopacifičke vrste ježinca Diadema setosum (Leske, 1778.) u morskom zaštićenom području otoka Zakintos (Jonsko more, Grčka)

“…This sea urchin is a dominant epibenthic grazer which in high densities can transform rocky reefs to barrens, outcompete indigenous echinoid species, and induce cascading effects on coastal ecosystems (Muthiga and McClanahan, 2020). Zakynthos MPA already suffers from overgrazing of rocky reefs by the thriving populations of other non-indigenous (Siganus luridus and Siganus rivulatus) and indigenous (Sparisoma cretense) herbivorous species, which are causing complex cascading effects in this protected ecosystem (Dimitriadis et al, 2021). Thus, a possible outbreak of D. setosum would further amplify the on-going biodiversity loss and ecosystem structure alteration of Zakynthos Island, as previously demonstrated in the eastern Mediterranean (Rilov et al, 2018).…”

Assessing the Effect of Full Protection on the Biomass of Ericaria amentacea and Understory Assemblages: Evidence from Two Mediterranean Marine Protected Areas

“…MPAs are the main global strategy to conserve and restore marine biodiversity and associated ecosystem services [76,77]. However, they cannot provide an exhaustive solution to the complexity of human-driven environmental issues affecting marine ecosystems [78,79], often leading to contrasting outcomes depending on reserve features, social and environmental contexts, and ecology and biology of species involved [32,42,80]. Our findings do not support the hypothesis of a significant effect of no-take zones in increasing the biomass of E. amentacea stands and associated assemblages with respect to control areas under lower levels of protection, although further investigations to increase the spatial and temporal extents of these assessments are needed.…”