Functional roles and redundancy of demersal Barents Sea fish: Ecological implications of environmental change

Abstract

When facing environmental change and intensified anthropogenic impact on marine ecosystems, extensive knowledge of how these systems are functioning is required in order to manage them properly. However, in high-latitude ecosystems, where climate change is expected to have substantial ecological impact, the ecosystem functions of biological species have received little attention, partly due to the limited biological knowledge of Arctic species. Functional traits address the ecosystem functions of member species, allowing the functionality of communities to be characterised and the degree of functional redundancy to be assessed. Ecosystems with higher functional redundancy are expected to be less affected by species loss, and therefore less sensitive to disturbance. Here we highlight and compare typical functional characteristics of Arctic and boreal fish in the Barents Sea and address the consequences of a community-wide reorganization driven by climate warming on functional redundancy and characterization. Based on trait and fish community composition data, we assessed functional redundancy of the Barents Sea fish community for the period 2004–2012, a period during which this northern region was characterized by rapidly warming water masses and declining sea ice coverage. We identified six functional groups, with distinct spatial distributions, that collectively provide a functional characterization of Barents Sea fish. The functional groups displayed different prevalence in boreal and Arctic water masses. Some functional groups displayed a spatial expansion towards the northeast during the study period, whereas other groups showed a general decline in functional redundancy. Presently, the observed patterns of functional redundancy would seem to provide sufficient scope for buffering against local loss in functional diversity only for the more speciose functional groups. Furthermore, the observed functional reconfiguration may affect future ecosystem functioning in the area. In a period of rapid environmental change, monitoring programs integrating functional traits will help inform management on ecosystem functioning and vulnerability.

Climate-driven benthic invertebrate activity and biogeochemical functioning across the Barents Sea polar front

“…Whether climate-driven changes in the functional architecture of communities lead to the decline, maintenance or enhancement of ecosystem functioning will not only depend on the level of functional redundancy across multiple supporting processes [113,114] but also on the environmental circumstances under which faunal reorganization take place. As there is a strong coupling between export flux, including episodic events of sinking ice algae aggregates [115], community structure [116] and benthic carbon cycling [117], it follows that complex dependencies between trait composition and the timing and quality of organic matter are likely.…”

Does functional redundancy affect ecological stability and resilience? A review and meta‐analysis

“…We excluded articles that were not relevant to the topic or did not link difference in functional redundancy to other measures of community stability or ecosystem function. We identified 32 replicate studies (i.e., quantitative assessments) across 15 published articles which met our set selection criteria and were retained for the quantitative meta‐analysis (Auster and Link 2009, Pillar et al 2013, Rice et al 2013, Gerisch 2014, Brandl et al 2016, Lipoma et al 2016, Nash et al 2016, Kaiser‐Bunbury et al 2017, Aune et al 2018, Correia et al 2018, da Costa Santana et al 2018, Richardson et al 2018, Sanders et al 2018, Bruno et al 2019, McLean et al 2019, Data ). These 15 articles included in the meta‐analysis spanned five continents and diverse biomes across aquatic and terrestrial realms (Appendix : Fig.…”

Deep demersal fish communities respond rapidly to warming in a frontal region between Arctic and Atlantic waters

“…The decrease in Arctic species might be explained by their low affiliation to the pelagic zone, low tolerance to increasing temperatures and increased predation from—and competition with the increasingly abundant boreal species. These are in general of larger body size, opportunistic, highly migratory and often more adaptive in a changing environment (Aune et al, 2018 ; Sunday et al, 2015 ). Many of these boreal species practice vertical diel migrations and feed in the upper water column, which connects them to changes in surface processes.…”