Comparing dominance relationships and movement of native marble trout (Salmo marmoratus) and introduced rainbow trout (Oncorhynchus mykiss).

Behaviour observations of the endangered native marble trout (Salmo marmoratus, Cuvier, 1829) and introduced rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) in the laboratory and in a tributary to the Idrijca River in Slovenia were combined to study the movements and dominance relationships between individuals of the two species in an open field test. Under laboratory conditions, no difference between the species was detected for neither time spent actively or distance moved. In species paired tests, rainbow trout initiated more aggressive behaviours towards marble trout than vice versa, and rainbow trout were clearly the dominant individuals. After simultaneous release in the river, marble trout immediately left the release area and spent twice as long time as rainbow trout until they settled in an area of the river; therefore, the release site was immediately occupied exclusively by rainbow trout. Thus, the dominant and aggressive behaviour of rainbow trout seen in the laboratory before release might have influenced marble trout's subsequent behaviour in the river, by marble trout leaving the areas occupied by rainbow trout and moving to locations further away from the release site. In the field, the marble trout occupied sites individually, whereas rainbow aggregated at a few locations. Rainbow trout showed higher movement activity in the morning compared to marble trout. There was a positive correlation between swimming speed in the laboratory and movement in the field for marble trout but not for rainbow trout. In conclusion, the results in this study support the need to end stocking of rainbow trout in rivers with native marble trout. To better understand the interaction between the species, and to develop efficient management plans to protect the native marble trout, reference behaviours should first be understood, and future research in sites where the two species do not co-exist is needed. This is especially important for marble trout for which behavioural research and data are lacking.

Engaging stakeholders in the assessment of NBS effectiveness in flood risk reduction: A participatory System Dynamics Model for benefits and co-benefits evaluation.

There is an imperative worldwide need to identify effective approaches to deal with water-related risks, and mainly with increasingly frequent floods, as well as with severe droughts. Particularly, policy and decision-makers are trying to identify systemic strategies that, going beyond the mere risk reduction, should be capable to deal simultaneously with multiple challenges (such as climate resilience, health and well-being, quality of life), thus providing additional benefits. In this direction, the contribution of Nature Based Solutions (NBS) is relevant, although their wider implementation is still hampered by several barriers, such as the uncertainty and lack of information on their long-term behavior and the difficulty of quantitatively valuing their multidimensional impacts. The activities described in the present paper, carried out within the EU funded project NAIAD, mainly aim at developing a participatory System Dynamic Model capable to quantitatively assess the effectiveness of NBS to deal with flood risks, while producing a multiplicity of co-benefits. The adoption of a participatory approach supported both to increase the available knowledge and the awareness about the potential of NBS and hybrid measures (e.g. a combination of NBS and socio-institutional ones). Specific reference is made to one of the demos of the NAIAD project, namely the Glinscica river case study (Slovenia).

Assessing stakeholders' risk perception to promote Nature Based Solutions as flood protection strategies: The case of the Glinscica river (Slovenia).

Evidences from flood risk management demonstrated that a deep understanding of the main physical phenomena to be addressed is often not enough but should be also integrated with stakeholders' knowledge and risk perception. Particularly, the effectiveness of flood risk management strategies is highly dependent on stakeholders' perception and attitudes, which play a critical role on how individuals and institutions act to mitigate risks. Furthermore, practitioners and policy-makers realized that grey infrastructures may not be the most suitable solution to reduce flood risk, and that a shift from grey solutions to Nature Based Solutions is required. Within this framework, the present work describes a methodology to enhance the Nature Based Solutions implementation by facilitating the generation, acquisition and diffusion of different stakeholders' risk perceptions. It is based on the combination of Problem Structuring Methods for the elicitation of stakeholders' risk perceptions through individual Fuzzy Cognitive Maps, and Ambiguity Analysis for the investigation of differences in risk perceptions and problem framing. The outputs of the Ambiguity Analysis, used during a participatory workshop, facilitated a dialogue aligning the divergences and promoting the social acceptance of Nature Based Solutions. These results of the implementation of this multi-step methodology in the Glinscica river basin (Slovenia) are discussed.

Natural Assurance Scheme: A level playing field framework for Green-Grey infrastructure development.

This paper proposes a conceptual framework to systematize the use of Nature-based solutions (NBS) by integrating their resilience potential into Natural Assurance Scheme (NAS), focusing on insurance value as corner stone for both awareness-raising and valuation. As such one of its core goal is to align research and pilot projects with infrastructure development constraints and priorities. Under NAS, the integrated contribution of natural infrastructure to Disaster Risk Reduction is valued in the context of an identified growing need for climate robust infrastructure. The potential of NAS benefits and trade-off are explored by through the alternative lens of Disaster Resilience Enhancement (DRE). Such a system requires a joint effort of specific knowledge transfer from research groups and stakeholders to potential future NAS developers and investors. We therefore match the knowledge gaps with operational stages of the development of NAS from a project designer perspective. We start by highlighting the key role of the insurance industry in incentivizing and assessing disaster and slow onset resilience enhancement strategies. In parallel we place the public sector as potential kick-starters in DRE initiatives through the existing initiatives and constraints of infrastructure procurement. Under this perspective the paper explores the required alignment of Integrated Water resources planning and Public investment systems. Ultimately this will provide the possibility for both planners and investors to design no regret NBS and mixed Grey-Green infrastructures systems. As resources and constraints are widely different between infrastructure development contexts, the framework does not provide explicit methodological choices but presents current limits of knowledge and know-how. In conclusion the paper underlines the potential of NAS to ease the infrastructure gap in water globally by stressing the advantages of investment in the protection, enhancement and restoration of natural capital as an effective climate change adaptation investment.