Habitat type drives the distribution of non‐indigenous species in fouling communities regardless of associated maritime traffic

Abstract

Aim: Biological invasions and changes in land and sea use are among the five major causes of global biodiversity decline. Shipping and ocean sprawl (multiplication of artificial structures at the expense of natural habitats) are considered as the major forces responsible for marine invasions and biotic homogenization. And yet, there is little evidence of their interplay at multiple spatial scales. Here, we aimed to examine this interaction and the extent to which the type of artificial habitat alters the distribution of native and non-indigenous biodiversity. Location: Southeast Pacific-Central Chilean coastline.Methods: Settlement plates were deployed upon two types of artificial habitats (floating and non-floating hard substrates) at a total of ten study sites, exposed to either international or local traffic. After colonization periods of 3 and 13 months, plates were retrieved to determine their associated fouling sessile assemblages at an early and late stage of development, respectively. Putative confounding factors (temperature, metal concentrations) were taken into account.Results: While traffic type had no detectable effect, there were strong differences in community structure between habitats, consistent across the study region. These differences were driven by non-indigenous species which contributed to 58% and 40% of the community structure in floating habitats after 3 and 13 months, respectively-roughly 10 times greater than in their non-floating counterparts. Assemblages on floating structures also displayed a lower decline in similarity with increasing distance between sampling units, being thus more homogenous than non-floating habitats at the regional scale. Main conclusions:With the absence of international traffic effect, the colonization success by non-indigenous species appears to be mainly habitat-dependent and driven by local propagules. Floating structures not only provide specific niches but characteristics shared with major introduction and dispersal vectors (notably hulls), and in turn constitute important corridors to invasions and drivers of biotic homogenization at multiple scales. | 63LECLERC Et aL.

Monitoring Non-indigenous Species in Port Habitats: First Application of a Standardized North American Protocol in the Mediterranean Sea

“…Several methodologies for sampling fouling communities in port habitats have been developed over the years. Most common techniques include (i) Rapid Assessment Surveys-RAS (e.g., Cohen et al, 2005;Campbell et al, 2007;Olenin et al, 2007;Minchin, 2012;Lehtiniemi et al, 2015;Marchini et al, 2015;Gewing and Shenkar, 2017;Ulman et al, 2017); (ii) net-assisted scraping (e.g., Ferrario et al, 2017;Ulman et al, 2017;Tempesti et al, 2020), including quadrat scraping during snorkeling or scuba diving (e.g., Neves et al, 2007;Awad et al, 2014;Ulman et al, 2019b); and artificial substrate units (ASU), such as (iii) two-dimensional settlement panels (e.g., Relini, 1977;Canning-Clode et al, 2013;Dos Santos Schwan et al, 2016;Lezzi et al, 2017;Marasinghe et al, 2018;Carlton, 2019;Leclerc et al, 2019); and (iv) three-dimensional artificial habitat collectors (e.g., Fowler et al, 2013;Gestoso et al, 2019;Outinen et al, 2019;Holmes and Callaway, 2020;Obst et al, 2020;Ros et al, 2020). Any of the above methods involves both advantages and disadvantages, and their success or suitability depend on the aim of the study.…”

Tanaididae (Crustacea, Tanaidacea, Tanaidomorpha, Tanaidoidea) on a Floating Dock, West Beach, Adelaide, South Australia: Introduced or Indigenous?

“…Despite the lack of pelagic life stage, an anthropogenic component to dispersal is possible for these tube-dwelling peracarids. Artificial floating docks represent a habitat favourable for species transported in hull fouling communities (Leclerc et al 2020). The agreement between the 655 nt CO1 sequences from the West Beach Hexapleomera species and H. sasuke collected in Japan, and perhaps also with the shorter CO1 sequence from a Zeuxo species collected in the Eastern Mediterranean, provide evidence supporting the long distance transport of this tanaid species.…”

“…Non-indigenous and cryptogenic species (of undetermined origin) are more prominent on hard substrates, especially among fouling communities on artificial structures and pilings (Hewitt et al 2004;Glasby et al 2007;Albano & Obenat 2019). Floating artificial structures, in particular, are colonised by non-indigenous species (Leclerc et al 2020). While crustaceans are among the more common marine invaders (Hewitt et al 2004;Ruiz et al 2015), tanaids are rarely included in records of introduced species.…”

First mussel settlement observed in Antarctica reveals the potential for future invasions

“…Although the initial steps of colonization may be hampered by a loss of facilitating taxa (e.g. barnacles), Mytilus have the potential to spread in a broad arrays of environments and habitats, ranging from diversified submerged moving vectors 25,37 to depauperate and ice-influenced intertidal shores 34 . At the extreme, the formation of extensive beds as observed in both indigenous and invaded regions 38 could have major impacts on native biodiversity, food web dynamics and ecosystem processes (e.g., nutrient dynamics) 3,39 .…”