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Toward a new generation of Ecological Assessment tools for the Management Coastal environment

Periodic Reporting for period 1 - TEAM-Coast (Toward a new generation of Ecological Assessment tools for the Management Coastal environment)

Reporting period: 2018-07-16 to 2020-07-15

"More than 60% of the worldwide population live on or near a coastline. These areas, at the interface between land and sea, are of considerable socio-cultural and economic importance (e.g. for tourism). They also host extraordinary biodiversity that supports many significant services to humankind such as maintenance of fisheries, water purification or carbon sequestration. However, human activities have deleterious effects the world’s coastal environments and their biodiversity. Among the main stressors are water pollution, urban development and habitat degradation, introduction of alien species, climate changes and their associated effects (e.g. water temperature increase, ocean acidification, sea-level rise). Yet, although these pressures often act simultaneously, their cumulative impacts on coastal biodiversity are poorly understood, mainly for two reasons. First, traditional approaches for monitoring coastal biodiversity present multiple constraints that limit observations to a small number of taxa, and restrain the extent of studies. Second, studies often focus on the impact of a single stressor and ignore interacting effects between stressors. Therefore, to efficiently improve the health of coastal environments, we need more integrative approaches to improve the monitoring of coastal biodiversity, and to disentangle the effects of the different stressors on biodiversity. To reach this goal, and thus support adapted management strategies, the TEAM-Coast project aims at developing a new generation of tools, based on molecular approaches named ‘environmental DNA’ (i.e. the study of genetic material retrieved in environmental samples such as water and sediments). These environmental DNA-based methods for monitoring biodiversity (also called ""eDNA biomonitoring"") seek to identify species living in a given area from DNA they release in the environment. These approaches have proved to be powerful tools for obtaining comprehensive and standardised biodiversity datasets in a relatively rapid and cost-efficient way. The TEAM-Coast project pursues thus three main objectives. The first one aims at developing protocols for the large-scale implementation of eDNA biomonitoring in costal environments. The second one aims at precisely describing the diversity and distribution of species assemblages, including species of ecological and economical interest, and at the same time identifying each of the main anthropogenic pressures, in order to finally assess the responses of communities to each of these pressures acting jointly. Ultimately, this project aims at developing ecological risk assessment models, based on environmental DNA data, and test management scenarios for striking the balance between human activities and the ecological integrity of coastal environments."
This project is conducted in collaboration between several institutions in France and Australia, and aims at developing a proof-of-concept for the integration of eDNA biomonitoring data into ecological risk assessment models. The study site is located in Northern Queensland, Australia. There, our work focuses on the combined impacts of two of the main sources of aquatic biodiversity loss worldwide: run off of contaminants of different nature (e.g. nutrients, pesticides, metals) into coastal waters and the introduction of alien species (i.e. species that are novel in a region because of their transport by human activities, such as shipping or aquaculture). Hundreds of water and sediment samples were collected in several estuaries and one harbour, reflecting a human-induced disturbance gradient. We first defined and assessed the appropriate strategy for the sampling, a pre-requisite for reliable eDNA analyses. Then, we developed protocols for the large-scale implementation of eDNA biomonitoring; we notably validated the use of fast and cheap DNA extraction protocol for the DNA-based biomonitoring of sediment biodiversity. DNA contained in these environmental samples was extracted and processed to identify species present at each sampling site. Five species groups of ecological and economic importance were targeted, including diatoms, fish and crustacea. eDNA data provided fine-scale resolution on the diversity and the composition of each of these groups in each sampled location. By combining these data with the levels for each stressor (measured locally), we identified the main factors (both natural and of anthropogenic origin) that affect biodiversity; and characterized the different responses of biological community (biodiversity) to human pressures. Results notably show a long-lasting differentiation of all biological communities under the influence of anthropogenic pressures, not necessarily in term of richness but rather of community composition. Meanwhile, we elaborated DNA-based strategies for monitoring species living on hard substrate (rocks, pontoons etc.), identifying alien species and evaluating the threat related with their presence (on-going experiment). Data currently available are being introduced into cutting-edge tools for assessing ecological risks. These models will allow to rank the relative importance of each stressor in each location, evaluate associated risks, and test management scenarios. Underlying models have been developed and their parametrization is currently in course.
Environmental DNA-based biodiversity monitoring evolved rapidly in the recent years, and is expected to be more and more adopted by authorities for examining ecosystem health. In this project, we developed dedicated and optimized protocols for the large-scale eDNA biomonitoring of coastal environments that will be useful to popularize the approach. We already characterized coastal biodiversity modifications in response to anthropogenic pressures, but additional data will provide new insights on seasonal changes. We further expect to obtain complementary information on communities living on hard substrate, and to properly assess the risks associated with alien species. Finally, this project proposes to go a step forward in the use of eDNA biomonitoring by developing ecological risks assessment models based on these methods. Studying a single stressor on a small number of taxa is now out-dated, and more integrative approaches are required to understand the responses of biological communities to the different pressures they are facing, and anticipating their restoration. Protection of coastal environments is at the heart of societal concerns due to their socio-economic importance and strong cultural identity. This project aims thus at providing a proof-of-concept for the integration of eDNA biodiversity data into ecological risk assessment models at a scale relevant for managers. These will be useful for public institutions, decision-makers and managers, wishing to develop integrative management models striking the balance between socio-economic interests and the maintenance of biodiversity and ecosystem health. As such, this project will provide concrete tools for management and policy-decision making process regarding conservation and the sustainable development of coastal areas.