Double Trouble: Synergy between Habitat Loss and the Spread of the Alien Species Caulerpa cylindracea (Sonder) in Three Mediterranean Habitats

Abstract

The role of habitat degradation on the spread of the alien green alga Caulerpa cylindracea is reported here by comparing observations achieved through a multi-year assessment on three Mediterraneans habitats, namely Posidonia oceanica meadows, Phyllophora crispa turf, and coralligenous reefs. Due to the peculiarity of the study site, both natural-reference and impacted conditions were investigated. C. cylindracea occurred in all the studied habitats under impacted conditions. High susceptibility to the invasion characterized impacted P. oceanica, where Caulerpa cover reached 70.0% in summer months. C. cylindracea cover did not differ significantly among conditions in P. crispa turf, where values never exceeded 5.0%. Conversely, the invasive green algae was low in abundance and patchily distributed in coralligenous reefs. Our results confirmed that habitat loss enhances the spread of C. cylindracea, although with different magnitudes among habitats. Dead matte areas of P. oceanica represented the most vulnerable habitat among those analyzed, whereas coralligenous reefs were less susceptible to the invasion under both the studied conditions.

Detecting trends in seagrass cover through aerial imagery interpretation: Historical dynamics of a Posidonia oceanica meadow subjected to anthropogenic disturbance

“…Due to its wide distribution and unique features, P. oceanica is protected by EU legislation and local measures both at species and habitat levels. Despite the legal framework, P. oceanica meadows are rapidly declining during the last century mainly due to human activities, climate changes and alien species invasion (Casoli et al, 2021;Jordà et al, 2012;Mancini et al, 2019;Marba et al, 2014;Montefalcone et al, 2007;Ruiz and Romero, 2003;Telesca et al, 2015). Although a widespread regression of P. oceanica meadows is reported at the basin level, the magnitude of this decline derived from anthropogenic pressures may vary depending on the considered geographic location and mapping technique (Bonacorsi et al, 2013).…”

Managing invasive hybrids through habitat restoration in an endangered salamander system

“…An appealing alternative strategy for managing biological invasions leverages natural selection, enabled through habitat restoration, to favor native taxa and reduce or eliminate non-native individuals or genotypes. Human-mediated habitat degradation is one of the most common predictors of successful biological invasions (14, 15). Such landscape modification can shift selective pressures, creating novel, invadable niches that select for non-native genotypes (e.g.…”