AUTHOR=Greeve Youk , Bergström Per , Strand Åsa , Lindegarth Mats 

TITLE=Estimating and scaling-up biomass and abundance of epi- and infaunal bivalves in a Swedish archipelago region: Implications for ecological functions and ecosystem services

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 10 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2023.1105999

DOI=10.3389/fmars.2023.1105999

ISSN=2296-7745

ABSTRACT=Coastal habitats are important zones of both ecological functions and ecosystem services. Both of these are currently under threat due to increased human activity. As suspension-feeders, bivalves play a key role in maintaining some of the regulatory functions of coastal ecosystems. Additionally, depending on their general life habits (epi- or infaunal), they provide other functions that influence the processes and thus the services of their surroundings. To understand how bivalves shape ecosystem services detailed information on their abundance, biomass and distribution at an ecosystem scale is critical. This information is critically lacking in the area of this study, the Swedish west coast. In order to alleviate this problem, a survey was conducted especially designed to representatively sample both epi- and infaunal bivalves from randomized locations in a naturally heterogeneous archipelagic region. Both abundances and biomass was recorded for all bivalve species in shallow habitats (<2 m). By stratifying sampling sites by exposure and sample locations by depth, it was possible to extrapolate our results over the whole study area using GIS layers. It was found that even though there exist a great variability among sites, in general epifaunal bivalves outweigh infaunal bivalves approximately 6 to 1 in biomass. In terms of abundance, the ratio is more or less reversed and infaunal  outnumber epifaunal species 3 to 1. Most bivalves were found at an intermediate level of exposure, but due to the areal extend of the sheltered inner-archipelago this was the most important habitat for bivalve abundance and biomass. It was also found that invasive epifaunal oyster Magallana gigas and the invasive infaunal clam Ensis leei both dominated their respective groups in terms of biomass. Though the survey was relatively small, these results serve as a valuable insight of the relative importance of epi- and infaunal bivalves in this region. They also provide a starting baseline for attempts to quantify ecosystem services provided by certain species or groups of bivalves in the future.