Modelling Species Response to Climate Change in Sub-Antarctic Islands: Echinoids As a Case Study for the Kerguelen Plateau
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THE KERGUELEN PLATEAU: MARINE ECOSYSTEM + FISHERIES Proceedings of the Second Symposium Kerguelen plateau Marine Ecosystems & Fisheries • SYMPOSIUM 2017 heardisland.antarctica.gov.au/research/kerguelen-plateau-symposium Modelling species response to climate change in sub-Antarctic islands: echinoids as a case study for the Kerguelen Plateau Thomas Saucède1, Charlène Guillaumot1,2, Loïc N. Michel3,4, Salomé Fabri-Ruiz1,2, Alexis Bazin1, Marie Cabessut1, Aurora García-Berro1, Amélie Mateos1, Olivier Mathieu1, Chantal De Ridder2, Philippe Dubois2, Bruno Danis2, Bruno David1, Angie Díaz5, Gilles Lepoint3, Sébastien Motreuil1, Elie Poulin6 and Jean-Pierre Féral7 1 Biogéosciences, UMR 6282 CNRS, Université Bourgogne Franche-Comté, 6 bd Gabriel, F-21000 Dijon, France, [email protected] 2 Laboratoire de Biologie marine CP160/15, Université Libre de Bruxelles, 50 av. Roosevelt, B1050 Bruxelles, Belgium 3 Laboratory of Oceanology, Freshwater and Oceanic Sciences Unit of reSearch (FOCUS), University of Liège, B6C, Allée du 6 Août 15, Quartier Agora, Sart- Tilman, B4000 Liège, Belgium 4 Ifremer, Centre de Bretagne, REM/EEP, Laboratoire Environnement Profond, F-29280 Plouzané, France 5 Departamento de Zoología, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile 6 Instituto de Ecología y Biodiversidad (IEB), Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Las Palmeras # 3425, Ñuñoa, Santiago, Chile 7 Aix Marseille Université/CNRS/IRD/UAPV, IMBE-Institut Méditerranéen de Biologie et d’Ecologie marine et continentale, UMR 7263, Station Marine d’Endoume, Chemin de la Batterie des Lions, 13007 Marseille, France Corresponding author: [email protected] Abstract In the Kerguelen Islands, the multiple effects of climate change are expected to impact coastal marine habitats. Species distribution models (SDM) can represent a convenient tool to predict the biogeographic response of species to climate change but biotic interactions are not considered in these models. Nevertheless, new species interactions can emerge in communities exposed to environmental changes and the structure of biotic interactions is directly related to the potential resilience of ecosystems. Trophic interaction studies can help predict species vulnerability to environmental changes using carbon (δ13C) and nitrogen (δ15N) stable isotope ratios to generate trophic models. Using new available data inputs, we generated robust SDM and trophic interaction models to assess the potential response and sensitivity of three echinoid species to future worst-case scenarios of environmental change in the Kerguelen Plateau region. The two modelling approaches provide contrasting insights into the potential responses of each species to future environmental changes with both approaches identifying Abatus cordatus to be particularly vulnerable due to its narrow ecological niche and endemism to near-shore areas. Coupling insights gained from trophic niche ecology with species distribution modelling represents a promising approach that can improve our understanding and ability to predict the potential responses of species to future habitat changes. Second Kerguelen Plateau Symposium: marine ecosystem and fisheries: 95–116 95 Modelling species response to climate change Saucède et al. Modéliser la réponse des espèces au changement climatique dans les iles subantarctiques : étude de cas chez les oursins du Plateau des Kerguelen Résumé Les multiples effets du changement climatique impactent d’ores et déjà les habitats marins côtiers des îles Kerguelen. Les modèles de distribution d’espèces (SDM) peuvent permettre de prédire la réponse des espèces au changement climatique mais ces modèles n’intègrent pas le rôle joué par les interactions entre espèces. La structure de ces interactions est pourtant déterminante dans le potentiel de résilience des écosystèmes. Elle peut être modifiée et de nouvelles interactions peuvent émerger dans les communautés exposées aux changements environnementaux. L’étude des interactions trophiques permet d’évaluer en partie la vulnérabilité des espèces aux changements environnementaux, l’analyse de bio-marqueurs tels que les rapports isotopiques du carbone (δ13C) et de l’azote (δ15N) permettant en particulier de produire des modèles d’interactions trophiques. Afin d’évaluer la réponse potentielle et la sensibilité d’espèces des Kerguelen aux changements environnementaux, nous avons produit des modèles de distribution d’espèces et de niche trophique grâce à de nouvelles données de terrain. Trois études de cas ont été choisies parmi les oursins, éléments communs et abondants des communautés benthiques côtières des Kerguelen. Les deux approches de modélisation prédisent des réponses contrastées des espèces aux changements environnementaux futurs selon le scénario le plus pessimiste du GIEC. D’autre part, les deux modèles identifient la même espèce, Abatus cordatus, comme étant particulièrement menacée en raison d’une niche écologique étroite et de son fort endémisme. L’utilisation conjointe de modèles de distribution et de modèles trophiques représente une réelle perspective d’amélioration des prédictions de réponse des espèces aux changements environnementaux. Keywords: species distribution model, trophic niche, isotopic niche, biotic interaction, distribution dynamics Introduction invasive species (Smith, 2002; Allan et al., 2013; Kargel et al., 2014; Molinos et al., 2015; Byrne In the Southern Ocean, and in the sub-Antarctic et al., 2016). Although no exotic species has been islands in particular, the multiple effects of climate reported in coastal marine habitats of the Kerguelen change are already perceptible and include, among Islands yet, this eventuality is not to be excluded other factors, an increase in sea-surface temperature (CCAMLR, 2008, 2013; Hureau, 2011; Féral et al., (Mélice et al., 2003; Ansorge et al., 2009, 2014), a 2019). decrease in rains, an increase in wind speed, and a rise of sunshine hours (Smith, 2002; Mélice et al., Species distribution modelling (SDM) has long 2003; Rouault et al., 2005; Le Roux et al., 2008). retained the attention of ecologists as a useful Future scenarios predict warmer, fresher, and more tool to predict species distribution range shifts in acidic waters, in addition to more extreme climatic response to climate change (Tingley et al., 2014; events and a more intense seasonality (Allan et Guillera-Arroita et al., 2015) and to address conser- al., 2013; Turner et al., 2014; Gutt et al., 2015). vation issues (Ross and Howell, 2013; Marshall et Such changes are expected to alter the structure al., 2014; Reiss et al., 2015; Zucchetta et al., 2016; and functioning of marine ecosystems (Allan et Hill et al., 2017). SDM relates species occurrence al., 2013; Gutt et al., 2015; Féral et al., 2016) and records with environmental predictors (Elith et may lead to shifts in species distributions and in al., 2006; Elith and Leathwick, 2009) to estimate extreme cases, local extinctions (Walther et al., a species’ ecological niche and predict the poten- 2002; Doney et al., 2011). Coastal marine habitats tial extent of suitable areas (Phillips et al., 2017). of the sub-Antarctic islands are particularly at risk Distribution range shifts under climate change can because shallow-water species do not necessarily be predicted by modelling species’ suitable areas have the opportunity to migrate to more favourable according to diverse ecological scenarios (Guisan areas. Moreover, new conditions such as warmer and Thuiller, 2005; Reiss et al., 2015). High- waters, may favour the expansion of exotic and risk areas for species viability can be depicted 96 Second Kerguelen Plateau Symposium: marine ecosystem and fisheries Saucède et al. Modelling species response to climate change on so-called risk maps, which can prove useful are only able to feed on a limited number of food for conservation purposes (Elith and Leathwick, sources (i.e. species with small trophic niches) and 2009; Václavík and Meentemeyer, 2012; Sànchez- typically exhibit low trophic plasticity. This makes Carnero et al., 2016), to define reference sites for them more vulnerable to qualitative and quantita- environmental monitoring (Constable et al., 2014; tive changes in food availability. Gutt et al., 2015, 2018), and for the establishment and management of marine protected areas (Chown Knowledge about trophic ecology of inves- et al., 2017; Coetzee et al., 2017; Gutt et al., 2018). tigated species is highly needed to improve the reliability of model predictions. Over the last dec- Running species distribution models to pre- ades, stable isotopes have proven to be one of the dict the geographic response of species to climate most reliable integrative trophic markers, and have change requires extensive and reliable information become a near-universal tool in ecology (Boecklen systems. Initiatives such as the Census of Ant- et al., 2011). The concept underlying this technique arctic Marine Life (CAML) and the International can be summarised by the idiom ‘you are what Polar Year (2007–2008) have recently contributed you eat’, whereby the isotopic composition of a to improving knowledge of species distribution consumer is a proportional mixture of the isotopic patterns in the Southern Ocean, by initiating and compositions of its food sources, with a slight implementing strong data policies at SCAR (the enrichment towards the heaviest isotope (Boecklen Scientific Committee on Antarctic research) level. et al.,