Benthic species of the Kerguelen Plateau show contrasting distribution shifts in response to environmental changes

Abstract

Marine life of the Southern Ocean has been facing environmental changes and the direct impact of human activities during the past decades. Benthic communities have particularly been affected by such changes although we only slowly understand the effect of environmental changes on species physiology, biogeography, and distribution. Species distribution models (SDM) can help explore species geographic responses to main environmental changes. In this work, we modeled the distribution of four echinoid species with contrasting ecological niches. Models developed for [2005–2012] were projected to different time periods, and the magnitude of distribution range shifts was assessed for recent‐past conditions [1955–1974] and for the future, under scenario RCP 8.5 for [2050–2099]. Our results suggest that species distribution shifts are expected to be more important in a near future compared to the past. The geographic response of species may vary between poleward shift, latitudinal reduction, and local extinction. Species with broad ecological niches and not limited by biogeographic barriers would be the least affected by environmental changes, in contrast to endemic species, restricted to coastal areas, which are predicted to be more sensitive.

Benthic ecoregionalization based on echinoid fauna of the Southern Ocean supports current proposals of Antarctic Marine Protected Areas under IPCC scenarios of climate change

“…In the sub‐Antarctic regions, the predicted changes in echinoid assemblages in South America, on the Campbell and Kerguelen plateaus are consistent with recent studies (Griffiths et al, ; Guillaumot et al, ). High extinction rates predicted for the Crozet islands, Kerguelen Plateau, and South Georgia could be related to a southward migration of the Antarctic Circumpolar Current, and particularly of the sub‐Antarctic and Polar fronts (Allan et al, ).…”

“…This high level of endemicity and the prevalence of a taxonomically limited number of speciose groups were found in many other marine groups in the Antarctic, and particularly on the continental shelf where species flocks were identified (Chenuil et al, ; Clarke & Crame, ; Eastman, ; Lecointre et al, ). Endemicity is even more pronounced in the less‐extended sub‐Antarctic ecoregions ( H. luculentum [#10], A. cordatus [#8], A. dufresni [ # 11 and #12], A. canaliculata [#8, #9, and #10], and species of the genus Pseudechinus [#8, #9, or #11, #12] and Goniocidaris [#10]) as already highlighted in previous studies (David et al, ; Fabri‐Ruiz et al, ; Guillaumot et al, ; Saucède et al, ). Species endemicity and adaptation to cold and subzero water temperatures make these organisms particularly vulnerable to climate warming, especially along the Antarctic Peninsula and in the sub‐Antarctic islands, which are subject to fast warming and are impacted by the synergetic effects of multiple stressors such as changes in sea ice regimes and seasonality, ice‐shelf collapse and iceberg scouring, reduced salinity, and increased in UV‐B radiation (Fabri‐Ruiz et al, ; Guillaumot et al, ; Gutt et al, ; Meredith & King, ; Turner et al, ).…”

“…This high level of endemicity and the prevalence of a taxonomically limited number of speciose groups were found in many other marine groups in the Antarctic, and particularly on the continental shelf where species flocks were identified (Chenuil et al, 2018;Clarke & Crame, 2010;Eastman, 2000;Lecointre et al, 2013). Endemicity is even more pronounced in the less-extended sub- (David et al, 2005;Fabri-Ruiz et al, 2018;Guillaumot et al, 2018;Saucède et al, 2014). Species endemicity and adaptation to cold and subzero water temperatures make these organisms particularly vulnerable to climate warming, especially along the Antarctic Peninsula and in the sub-Antarctic islands, which are subject to fast warm- Depth, sea ice concentration, and seafloor temperature are the three environmental factors that most contribute to the definition of ecoregions ( Figure 3) which is in line with previous findings obtained for Antarctic echinoids Pierrat et al, 2012).…”

“…ENM offers a baseline for detecting, monitoring, and predicting the impact of climate change on species and biota (Gutt et al, 2015(Gutt et al, , 2017Kennicutt et al, 2014). An increasing number of studies have used ENM over the last decade to predict the distribution of pelagic species in the SO (Duhamel et al, 2014;Loots, Koubbi, & Duhamel, 2007;Nachtsheim, Jerosch, Hagen, Plötz, & Bornemann, 2017;Pinkerton et al, 2010;Thiers, Delord, Bost, Guinet, & Weimerskirch, 2017; Xavier, Raymond, Jones, & Griffiths, 2016) but few were developed for benthic organisms (see however: Basher & Costello, 2016;Fabri-Ruiz, Danis, David, & Saucède, 2018;Gallego, Dennis, Basher, Lavery, & Sewell, 2017;Guillaumot et al, 2018;Pierrat et al, 2012).…”

“…Marine life of the SO displays unique physiological characteristics and life-history traits including high levels of endemism (Griffiths, Barnes, & Linse, 2009;Kaiser et al, 2013;Saucède, Pierrat, & David, 2014), adaptations to seasonally subzero water temperatures with high sensitivity to increase in temperature due to their narrow thermal niche (Cheng & William, 2007;Peck, 2016Peck, , 2018Portner, Peck, & Somero, 2007), and brooding (David & Mooi, 1990;Hunter & Halanych, 2008;Sewell & Hofmann, 2011), which make it particularly vulnerable to environmental changes (Guillaumot et al, 2018;Ingels et al, 2012;Lohrer, Cummings, & Thrush, 2013;Peck, 2005;Peck, Morley, & Clark, 2010;Peck, Webb, & Bailey, 2004). Multiple impacts of climate change have been documented on SO benthic marine ecosystems that are particularly endangered (Bonsell & Dunton, 2018;Constable et al, 2014;Le Guen et al, 2018;Reygondeau & Huettmann, 2014;Rogers et al, 2020;Sen Gupta et al, 2009).…”