Amphipod assemblages associated with native habitat-forming seaweeds of the Alboran Sea: influence by environmental protection and biogeographical patterns

Abstract

Context Despite the key ecological role played by epifaunal communities associated with macroalgae in temperate coastal rocky shores worldwide, biodiversity and ecological patterns of their associated invertebrate communities are still poorly known. Aims The present study aims to compare the amphipod assemblages associated with the dominant canopy-forming macroalgae in shallow subtidal habitats of the Alboran Sea, as well as to explore its biogeographical patterns and the influence of protection measures. Methods Replicate samples of both Ericaria selaginoides (=Cystoseira tamariscifolia) and Halopteris scoparia were collected at two different bioregions within the Alboran Sea and both inside and outside marine protected areas. Key results Amphipoda was the dominant taxon within the mobile epifaunal community, both in terms of number of species (47 different species were recorded) and individuals (>70% of the total abundance). Assemblages associated with E. selaginoides and H. scoparia differed and showed a marked response to the Mediterranean–Atlantic gradient in this region; species related to warmer waters become increasingly dominant towards the east. However, there were no significant differences in amphipod assemblage composition, abundance or species richness between protected and non-protected areas. Conclusions Obtained results highlighted the relevance of these native macroalgae as habitat for epifauna, as well as the influence of macroalgal identity and regional biogeographical patterns on amphipod distribution. Implications This study provides valuable baseline information to monitor human-induced changes such as coastal pollution, invasive species, and climate change. It also draws attention about the uncertain response of epifaunal communities to management strategies (such as marine protected areas) and ecological processes (e.g. increasing predation pressure).

The role of grazers in early-life stages of Cystoseira sensu lato can be crucial in the restoration of marine forests

“…), and an isopod (Idotea balthica) was assessed in laboratory. The species and their densities were selected in function of field observations and information reported in the literature for fucoid species (Engkvist et al, 2000;Chemello and Milazzo, 2002;Gozler et al, 2010;Gunnarsson and Berglund, 2012;Suzuki et al, 2020;Hong et al, 2021;Navarro-Barranco et al, 2022).…”

“…Although local stressors and regional variations can control marine forest dynamics (Krumhansl et al, 2016;Smale, 2020;Verdura et al, 2021;Smith et al, 2022), many studies have shown how sea urchins, native and invasive herbivorous fish, and even omnivorous fish are potential threats to macroalgal communities and responsible for the formation of turfs or barren ground extensions (Tegner et al, 1995;Vergeś et al, 2014;Vergeś et al, 2016;Papadakis et al, 2021). Mesograzers associated with marine forests such as decapods, gastropods, amphipods, and isopods can significantly participate in the grazing of different life stages of forest-forming species, but little is known about the magnitude of their possible effects (Arrontes et al, 2004;Jonne et al, 2006;Molis et al, 2010;Gunnarsson and Berglund, 2012;Hong et al, 2021;Navarro-Barranco et al, 2022).…”