ECOSYSTEM SENSITIVITY TO INVASIVE SPECIES - EnSIS
The introduction of invasive species is now considered a major problem to marine ecosystems. The American jack knife clam Ensis directus represents a well-investigated and -documented example of such invasion in North-West European coastal waters. Given its high densities and habitat preferences, a major impact onto the Abra alba community, the biologically highest valuated macrobenthic community along the Belgian coast, was hypothesized. The high densities in combination with its fast growth further feed the discussion on a possible future commercial exploitation of the species. However, before being able to tackle both issues, still many ecological baseline questions remain unanswered. The project “Ecosystem Sensitivity to Invasive Species – EnSIS” will aim at (1) characterizing the ecological features of E. directus in Belgian waters, (2) evaluating the ecological impacts of E. directus’ introduction and (3) assessing the impact of possible E. directus’ fisheries.
As no reliable data on Ensis spp. populations are available from the Belgian part of the North Sea (BPNS), a first necessary and inevitable step will be to collect baseline field information on Ensis directus, using the most appropriate and reliable sampling techniques (Work package 1 “New data collection”). This newly collected data on E. directus’ distribution as well as population size and structure, in relation to its habitat features and accompanying macrobenthic fauna, will then feed into Work package 2 “Ecological features”, where (1) its habitat and spatial distribution will be both directly characterized or assessed as well as mapped through habitat suitability modeling and (2) its accompanying macrobenthic species assemblage will be qualified and quantified. Based on this knowledge the impact of E. directus on the spatial distribution of wintering seaducks, mainly black scoter Melanitta nigra and velvet scoter Melanitta fusca, at the BPNS will be assessed (Work package 3). Work package 3 will further focus on the identification of the potential impact of E. directus on the indigenous macrobenthic fauna through a comparison of existing macrobenthic data from before versus after its introduction in 1987. Work package 4 will finally address the impact of a possible future E. directus fisheries on (1) its accompanying macrofauna, making use of (a) the habitat suitability modeling exercise from Work package 2 as well as (b) a biological trait analysis as a function of fisheries disturbance and (2) on its population, using literature data on E. directus (and other bivalve) population dynamics and life history features.
Given the need for a wide expertise regarding E. directus and, by extension, macrobenthos and its habitat in general, a research team with a diverse expertise was set up. Each partner brings in a specific expertise, needed to comply with the objectives of this project. Having a rich background in (1) invasive species’ field biology and macrobenthos research in general en (2) project coordination, the KBIN-MUMM team is selected as project coordinator. This macrobenthos expertise is completed with the macrobenthos expertise from UGENT- Marine Biology Section, more specifically its experiences with habitat suitability modeling and grain size analysis, and from IMARES, our foreign partner with a unique expertise in Ensis spp. stock assessment. Supplementary expertise for seaducks was retrieved from INBO, whereas KBIN-MUMM further ascertains the provision of (full-coverage) environmental information on the BPNS and put its expertise with acoustic techniques at the disposal of the consortium.