Combined Abundance of All Vulnerable Marine Ecosystem Indicator Taxa Inadequate as Sole Determiner of Vulnerability, Antarctic Peninsula

Abstract

In order to achieve conservation objectives and preserve the biodiversity of the Southern Ocean, a variety of ecosystems must be protected. This holds especially true for the benthic communities of this region that are characteristically mosaic in their spatial distributions. As such, disparate communities cannot be comprehensively assessed by a single blanket methodology. Herein, evidence appropriate to the diverse characteristics of the communities encountered during a submarine expedition demonstrates the particular vulnerability of four sites that exemplify VMEs as defined by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and the UN’s Fisheries and Agriculture Organization (FAO). Three sites are identified as VMEs based on highly significant abundances of indicator taxa. A fourth is identified based on a high density of cold-water coral taxa, many of which were not observed in abundance at the sites that were triggered as vulnerable by a significantly high abundance of all indicator taxa. The VME at this latter site was richly diverse in coral taxa, many of which are considered particularly vulnerable to climate change, as well as critical for their potential for genuine blue carbon sequestration. As of November, 2018, all four sites are now registered with CCAMLR as VMEs and thus, are afforded protection from all bottom fishing activities. However, if consideration isn’t given to the composition and/or diversity of VME indicator taxa present, in addition to overall abundance/density, some of the most vulnerable communities are left at risk. A blanket threshold for all VME taxa adhered to in fisheries management of the Southern Ocean, and other high seas areas, is grossly insufficient. Without taking a more precautionary approach to identifying and protecting VMEs, CCAMLR will not be able to meet its conservation objectives and may even be putting Antarctic fisheries at risk.

Use of emerging technologies to help measure fjordic biodiversity and blue carbon: mini-manned submarines and autonomous underwater vehicle swarms

“…The example application we highlight is the ability of mini-submarines and AUVs to aid with biodiversity visualization and quantification in a species-and carbon-rich hotspot ecosystem, fjords. Although these tools could help science with some bottlenecks in field assessments, such as levels of biota density and (with calculations of mean carbon per individual per species) estimates of local carbon storage in macrobiota [17,22,23] , other applications of new technology are also needed. On a larger scale, the potential for marine technology to help with carbon capture and storage (CCS) is recognized as huge and may be key in aiding the next step of removal from the carbon cycle to sequestration.…”

“…Such data can then be directly compared across time (e.g., years, monitoring change) or space (habitats, environments or regions). It allows for the determination of change along polar basin troughs [23] , emerging fjords [17] , walls [24] or, when used in combination with physical collection of relevant local specimens and carbon content analyses of these, estimates of epibenthic carbon stocks [25] .…”

“…Each organism is identified as far as possible, and the density of each taxon or functional group is then scored using image analysis. Reference data of biomass (drymass, ash-free drymass and carbon composition) at size for the relevant taxon/functional groups are then referred to, such that the densities of each biota can be converted into estimated carbon per organism type, per size [17,[21][22][23][24]33] . Such data proves more powerful when combined with adjacent sediment core or grab collection, followed by the analysis of organic and inorganic carbon accumulation [34] .…”

Species Diversity and Community Structure of Macrobenthos in the Cosmonaut Sea, East Antarctica

“…Anthropogenic climate change is causing the retreat of glaciers [31], and the recovery of communities is predicted to be extremely slow because growth is slow in the cold waters of the Southern Ocean. Therefore, the protection of vulnerable communities as refugia becomes more urgent if their biodiversity is to survive the accelerated rate of glacial carving [32].…”

Vulnerable, but Still Poorly Known, Marine Ecosystems: How to Make Distribution Models More Relevant and Impactful for Conservation and Management of VMEs?

“…Coral communities (e.g. bamboo coral, Isididae) are very diverse, slow growing, and have been associated with populations of commercial fish, while being fragile and vulnerable to fishing gear (Maynou and Cartes, 2012;Lockhart and Hocevar, 2021). Forming structurally complex and functional habitats, VME indicator taxa have been depicted as "ecosystem engineers" (Kenchington et al, 2014;Lockhart and Hocevar, 2021) and have a critical influence on marine macrofaunal assemblages, through strengthened links between pelagic and benthic food webs (Ashford et al, 2019).…”