Fish biodiversity scenarios in the Seine basin under global change and connectivity constraints – SEINARIOS

Living organisms that face global change, and subsequent major environmental disruptions, have three options: to move and find more suitable environmental conditions, to adapt to new environmental conditions, or to extinct [1]. To better predict ecological dynamics and remedy biodiversity loss, several modelling approaches have been developed. However, the understanding and integration of species dispersal and extinction still require development, in particular when it comes to ecosystems highly fragmented by anthropogenic infrastructures [2,3]. Traditional models of fish species distribution that are habitat-centred do not explicitly take into account the quality neither the connectivity of landscape matrix and hydrological network across which the organisms migrate and disperse [4,5]. While ecological connectivity is a key concept in metacommunity ecology [6] and an essential property of the landscape to maintain biodiversity [7,8], its modelling is genuinely challenging [9–11], in particular in multi-taxa context [12] and anthropized ecosystems. The hydrological connectivity underlying the ecological connectivity is modified by different types of anthropogenic infrastructures (e.g. dams, sluices, channels) [2,13]. Furthermore, water flow variations [14,15] and growing drought periods [16] as expected in France, may modify both longitudinal and lateral connectivity [17,18], favour fish species invasions and/or extinctions [19,20], and amplify the consequences of global change on biodiversity [21]. To now, all these relationships and the corresponding uncertainties remain to be elucidated, characterized and quantified in order to better predict biodiversity distribution.

The thesis aims to address the following question: what is the role of connectivity and riverscape context in the future of biodiversity under global change, and subsequent hydrological modifications in an anthropized basin?

To address this question, your work will mainly consist in analysing data and developing modelling approaches that can explicitly integrate hydroclimatic and landscape factors, as well as functional, longitudinal and lateral connectivity into predictive models of species distribution and of biodiversity. This will allow disentangling the respective role of the different factors in species distribution. You will then use these models with scenarios of hydroclimatic, landscape and human development changes as projected in the basin in order to produce scenarios of future biodiversity. Your work will apply on the particular case of the Seine basin, in virtue of the tight cooperation and partnership with the public Seine-Normandy Water Agency. You will have several large datasets already available in the research unit (e.g. fish monitoring observations >1200 stations, river barriers, land-cover / land-uses, hydroclimatic archives and simulations) and you will compile additional datasets during the PhD in collaboration with the basin’s stakeholders (e.g. scenarios of future land, water and river uses). You will be strongly encouraged to build collaborations with other INRAE research units (e.g. RiverLy in Lyon), and national and international institutions (e.g. via on-going NAVIDIV project: https://www.fondationbiodiversite.fr/en/the-frb-in-action/programs-and-projects/le-cesab/navidiv/) to perform inter-basin and transnational comparisons. Ultimately, these biodiversity scenarios accounting for global change and connectivity constraints will allow you to identify and prioritize areas for preserving ecological connectivity and biodiversity and provide guidance for sustainable basin management.

**Main activities**
Your activities will mainly be to: handle fish monitoring and environmental data, process GIS data, use, adapt and develop connectivity models for fish species [e.g.22–26], develop and apply spatial-explicit statistical modelling of joint species distributions [e.g.27,28], build and handle scenarios of hydroclimatic, land-use and river use changes in collaboration with an transdisciplinary team, project future distribution of species, and biodiversity depending on combinations of contrasted scenarios, and estimate the uncertainties across the different steps of the work [e.g.29–31].

**PhD location & supervision**
You will be hosted by the research unit Anthropized Continental Hydrosystems – Resources, Risks, Restoration (HYCAR) at INRAE, located in Antony (92, Ile-de-France region, France). HYCAR (https://www6.jouy.inrae.fr/hycar) gathers competencies in hydrology, ecology and ecological engineering. Its topics of research include water resources and risks (estimation, prediction and management), ecological functioning and restoration of freshwater ecosystems under multiple anthropogenic pressures across scales, and modelling and remediation of pollutant transfer from agricultural practices. In this research unit, you will belong to the team River Hydroecology (https://hef.inrae.fr/).
You will be co-supervised by the lab Evolution & Biological Diversity (University of Toulouse, France), and more specifically, by the team AQUAECO (https://edb.cnrs.fr/recherche/equipe-aquaeco/) that works on the impacts of climate change, ecosystem fragmentation, biological invasions and resource overexploitation in freshwater ecosystems. You will belong to the Graduate School SEVAB in Toulouse. In virtue of this co-supervision and graduate school location, you will sometimes have to travel between Antony and Toulouse (c.a. twice a year).
Your thesis will be co-supervised by Dr. Aliénor Jeliazkov (metacommunity ecology; INRAE Antony), Dr. Guillaume Thirel (hydroclimatology; INRAE Antony), and Prof. Gaël Grenouillet (habilitated; fish community ecology under scenarios of global change; EDB lab). You will benefit from the support and expertise of the River Hydroecology team, including Dr. Jérôme Belliard (fish communities of the Seine river basin) and Dr. Céline Le Pichon (functional connectivity in freshwater ecosystems).

**Funding, salary & working environment**
– The PhD is co-funded by the INRAE’s research program Biosefair “Promote biodiversity and strengthen networks of ecosystem services” and the public Seine-Normandy Water Agency.
– Gross salary: 1,874 EUR / month (provisional net salary 1,506 EUR / month). Travels fees in relation to the PhD work will be covered.
– On-site access to institutional catering, sport & culture club, and car parking facilities
– INRAE Antony: Easy access by public transport (https://www6.jouy.inrae.fr/hycar/Comment-venir-a-INRAE-Antony/Acces); at one hour from amazing Paris.

**Duration & starting date**
Contract type: doctoral contract
Duration: 36 month (3 years)
Starting date: From the 1st of October 2021 and at latest the 1st of December 2021

**Expected skills**
– Required: MSc degree (Master of Science) in Ecology; Experience in research; Experience in statistical modelling (including in R); Abilities in GIS processing
– Highly recommended: Experience in species distribution modelling and/or ecological connectivity modelling; Experience with freshwater ecosystems
– Potential assets: Knowledge on fish communities; Inclination towards metacommunity ecology; Drawn to inter- and transdisciplinary work
– Expected traits: Autonomous in the work; Good interpersonal skills; Organised.

**To apply to the position:* *
The application should include:
(1) CV
(2) cover letter showing your interest in the topic and your personal vision of the research to be realised (2 pages max.)
(3) the name and contact details of 2 to 5 reference persons
(4) if possible, MSc degree diploma and/or prelims transcript of marks or equivalent.

Please send your application to the whole supervisory team: Alienor Jeliazkov ([email protected]), Guillaume Thirel ([email protected]), Gaël Grenouillet ([email protected]), Jérôme Belliard ([email protected]) and Céline Le Pichon ([email protected]) **by specifying [PHDSEINARIOS] in the mail subject**.

**Application deadline: ** 15th of August 2021
The interviews will be held as we go along the recruitment process.

**For any question, please feel free to contact us. **

**Cited literature references**
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3. Zajicek, P., Radinger, J. & Wolter, C. Disentangling multiple pressures on fish assemblages in large rivers. Sci. Total Environ. 627, 1093–1105 (2018).
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29. Buisson, L., Thuiller, W., Casajus, N., Lek, S. & Grenouillet, G. Uncertainty in ensemble forecasting of species distribution. Glob. Change Biol. 16, 1145–1157 (2010).
30. Stoklosa, J., Daly, C., Foster, S. D., Ashcroft, M. B. & Warton, D. I. A climate of uncertainty: accounting for error in climate variables for species distribution models. Methods Ecol. Evol. 6, 412–423 (2015).
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