Modelling antropogenic impact on primary production of sado estuary

The assessment of human impact on complex estuarine systems is a multidisciplinary task that is highly demanding in terms of measurements and fieldwork. Nowadays the use of inexpensive and reliably modeling tools can substantially reduce the amount of measurements needed to characterize a system. These tools are also a convenient way to forecast the future evolution of the system and to study the impact of different scenarios of human influence. In this communication a modeling system composed by hydrodynamic, transport and ecological models is used to assess the current trophic state of Sado Estuary (Portugal) and to predict the future trends of the system based on different scenarios of human intervention. Special care is taken to the impact of changing riverine nutrient loads. Sado estuary is a large European estuary that has been considered until now in good trophic conditions with eutrophication appearing only in some isolated spots. Nevertheless in recent years some studies point out that the situation is changing. Sado estuary is a system with strong environmental opposing interests. It hosts a major industrial and urban center around the city of Setúbal and the upper reaches are used to intensive cultures such as rice. On the other hand the estuary possess an important ecological value since it is used by several important species of fish as a spawning and nursery area and it’s wetlands are used by many species of birds as winter shelters. Due to it’s importance the majority of Sado Estuary is considered as Natural Reserve.

Landscape metrics as indicators of coastal morphology and its use in ecological niche modelling of seagrass species

Dependence of some species on landscape structure has been proved in numerous studies. So far, however, little progress has been made in the integration of landscape metrics in the prediction of species associated with coastal features. Specific landscape metrics were tested as predictors of coastal shape using three coastal features of the Iberian Peninsula (beaches, capes and gulfs) at different scales. We used the landscape metrics in combination with environmental variables to model the niche and find suitable habitats for a seagrass species (Cymodocea nodosa) throughout its entire range of distribution. Landscape metrics able to capture variation in the coastline enhanced significantly the accuracy of the models, despite the limitations caused by the scale of the study. We provided the first global model of the factors that can be shaping the environmental niche and distribution of C. nodosa throughout its range. Sea surface temperature and salinity were the most relevant variables. We identified areas that seem unsuitable for C. nodosa as well as those suitable habitats not occupied by the species. We also present some preliminary results of testing historical biogeographical hypotheses derived from distribution predictions under Last Glacial Maximum conditions and genetic diversity data.