Modelos ecológicos preditivos para avaliar os efeitos da elevação do nível do mar em macroinvertebrados bentônicos estuarinos

Abstract

Among the main effects of climate change in the coastal zone, the sea-level rise is one of the most relevant as it can lead to flooding, coastal erosion and salinization of soils and water bodies. Estuaries in particular may be the first environments to be affected by saline intrusion induced by sea-level rise. Changes in the salinity distribution pattern in the estuary can affect the organisms (fauna and flora), as they had to adapt to living in this ecosystem that is subject to strong gradients (e.g., salinity, sediment). Among the organisms that inhabit the estuary, the benthic fauna has been used successfully to assess ecological effects of natural or antroppgenic changes. Additionally, these organisms are used in the construction of predictive ecological models that can provide valuable information about the responses to future changes in the estuarine environment, such as sea level rise. This study proposes the investigation of i) the main predictive ecological models that use the benthic fauna; ii) the studies that simulated the effects of sea-level rise in estuaries and iii) to simulate the effect of sea-level rise on the macrobenthic spatial distribution in a estuary using species distribution modeling. The main predictive models applied to benthic organisms used species distribution modeling in environmental monitoring to predict human impacts and alterations caused by climate change and introductions of exotic species. The use of well-established approaches, the incorporation of machine learning techniques and the use of open-source software (e.g., R) contributed to the growth of this research topic. The main sea-level rise effects in estuaries were saline intrusion, flooding and the ecological effects associated with these two phenomena. The synthesis obtained with data from numerical models indicated a direct effect of sea-level rise on saline intrusion and highlighted the influence of river discharge. The ecological effects of saline intrusion and flooding have been studied primarily through manipulative experiments or using approaches based on geographic information systems (e.g., digital elevation models). Since numerical hydrodynamic models are more accurate in predicting such effects, the use of such predictions in ecological models should be encouraged. Species distribution modeling was successfully applied to predict the saline intrusion effects on the spatial distribution of eight families of benthic invertebrates in the Jaguaripe estuary. In general, local extinction and colonization processes resulted in migrations to the estuary innermost regions. These migrations can result in an effect known as estuary marinization and may cause important environmental changes as saline intrusion advances. This study showed that predictive ecological models are useful for understanding the ecological impacts of sea-level rise in estuarine benthic fauna and are an important tool for managers in planning mitigation actions.