Final Report Summary - BIOWEB (Towards an Ecosystem-based Approach of Marine Resources: Linking BIOodiversity, Food WEBs, Ecosystem Services and Drivers)
Marine ecosystems are subjected to various anthropogenic and environmental disturbances since historic times, which are cumulative and can act synergistically, additively or antagonistically. These are human activities such as fishing, pollution or eutrophication, and due to environmental drivers related to changes in oceanographic dynamics and, ultimately, primary productivity. To understand and predict ecosystem dynamics represent a scientific challenge although little is known about cumulative effects and their combined impacts. The objective of BIOWEB was to advance on the quantification on how the structure and functioning of marine food webs changes under human and environmental cumulative and combined disturbances, and develop an understanding of how the changes in diversity and abundance of marine organism impact ecosystem functioning, and ultimately the services that marine ecosystems provide to humans and to ecosystem health. In BIOWEB I have developed several complementary analyses using different datasets and indicators to advance on our understanding on human and environmental cumulative impacts on marine ecosystems. Results confirm that considering cumulative impacts in marine ecosystems are essential to explain past and current spatial-temporal dynamics of marine resources. Frequently, these impacts accumulate in a synergistic or antagonistic way, thus their impacts cannot be predicted as a simple sum of individual impacts. Cumulative impacts affect commercial resources, but also non-commercial resources, and ultimately translate into structure and functional changes of marine ecosystems, with impacts to ecosystem services, such as food production and food security. Fishing activities still have a large impact on marine resources worldwide, and their impacts are especially large in areas with a poor resource management. Habitat loss is also a source of big disturbance, especially in coastal areas, and it is increasing in offshore ecosystems due to exploration and exploitation of mineral resources and deep sea fishing. Pollution and eutrophication are also posing large impact on the coastal areas and due to shipping and boat activities, are also moving to offshore areas. Climate change effects are very important for some species and areas and will certainly increase in the future, with uncertain outcomes. In enclosed regions such as the Baltic or Mediterranean Sea, the impact of invasive species has exponentially increased and will continue to rise in the future. In general, marine ecosystems are changing towards ecosystems with smaller organisms (e.g. small fish and invertebrates). The importance of invertebrates in marine ecosystems is increasing, especially of those species that have high turnover rates (e.g. cephalopods, small crustaceans and pelagic cnidarians). These organisms tend to be less commercial and highly vulnerable to environmental fluctuations. There are also a larger proportion of invasive species, which in some cases have commercial value, but in other cases can be poisoning and dangerous for humans. These changes render marine ecosystems more variable, less resilient to perturbations and thus more prone to change to unknown states when cumulative human impacts are too high. Results from BIOWEB allow to progress towards a more complex and realistic analysis under the global change context, and evaluate the impact of human and environmental impacts on marine ecosystems.