PREMOSGAMES · Predictive model of seagrass growth and meadow spreads

Final Activity Report Summary - PREMOSGAMES (Predictive model of seagrass growth and meadow spreads)

Recently, seagrass meadows and their associated ecosystem have been included in the European Directive (2000/60/CE) as a key factor in coastal zones that must be monitored as a quality element. However, although seagrass meadows are among the richest and most productive ecosystems on earth, they are declining as a result of natural and human-induced disturbances in coastal and estuarine waters worldwide. This project was aimed to build a predictive spatially explicit seagrass model as a tool for scientists and managers in the development of future policies aimed at management, monitoring and restoration of seagrass meadows. Besides this main aim several secondary objectives were defined in the course of the project. A step-wise approach was adopted in the implementation of the project in which each step has its own scientific innovative objective. Below the main steps accomplished in the project are summarised. - The theoretical framework necessary to develop complex functional-structural seagrass models has been developed and published in an international peer-review journal. A basic assumption of the method is that each seagrass species has imprinted in its genome a range for the plant dynamic parameters (plastochrone indices, leaf elongation rates, rhizome elongation rates, leaf loss rates, branching pattern, etc...), which finally leads to the individual shoot morphology and plant architecture. Plants are arranged in a meadow, whose features (density, canopy properties, meadow development, etc...) are emergent properties depending on the individual plant morphology. Through the meadow properties, physical and chemical drivers such as light, hydrodynamic conditions or nutrient concentrations will be modified. Individual plants will respond to these changes, which in turn will change the properties of the meadow etc. until a new steady state is reached. - The pattern of growth of the seagrass Zostera noltii and the dependence of plant morphology on dynamic parameters have been described and published in an international peer-review journal. This description was essential since it allowed generalising the pattern of growth. Based on this description the model was upgraded also for a large number of seagrass species. In addition, the individual plant development and features of the belowground system and its dependence on apical dominance and clonal integration has been described and published. Results from this study demonstrated that seagrasses may optimise their branching pattern and meristem development with respect to abiotic conditions and that branch formation and rhizome network development is a species-specific trait and has a strong seasonal and site-specific dependence. - Dynamic plant parameters (plastochrone indices, leaf elongation rates, rhizome elongation rates, leaf loss rates, branching pattern ...) showed a high dependence on light levels, nutrient supply and hydrodynamic conditions. This set of data was used to parameterise the dynamic plant parameters and thereby include into the model both the macro and micro-abiotic gradients generated by meadow development. Results derived from this set of experiments have been published in different international peer-review journals. - The interaction between flow characteristics (flow velocity, waves...) and canopy properties (interspecific differences and intra-specific variability) showed a large influence on several crucial processes occurring at plant, meadow and community levels (water renewal within the canopy, nutrient uptake, food supply to filter feeders organisms, light climate within the canopy). These new findings were essential in upgrading the model results beyond seagrass meadow to the ecosystem level.

Data: CORDIS, © European Union