The “Known” Projections of human drivers

1. The “Known”Projections of human drivers • Human population density will increase, especially in developing countries and on the coast • In developing countries this will increase most human impacts on coastal ecosystems: • Habitat loss and degradation • Shoreline development • Physical disturbance (humans, tourism, …) • Degradation in water quality • Nutrient loading • Chemical pollution • Oxygen depletion • Freshwater conversion / changes in hydrograph • Species invasions • Where human drivers intensify their ecological impact will depend largely on management practices, technology transfer, education • Developed countries will see leveling off in most impacts • Land use changes: • Deforestation is leveling off • Agriculture will intensify especially in developing countries • Projected large increases in protein demand (aquaculture, life-stock production) will increase nutrient loading • Accelerated sea level rise will increase loss of shallow estuarine and coastal habitat (e.g. wetlands, oysters, seagrasses)

2. The “Known”Projections of impacts on biodiversity • Large shifts in species compositions resulting in new mixes of species • simplification and homogenization • extinctions and extirpations • Accelerated invasions • Increase in small, fast-growing, opportunistic species • Decline in specialists • Recovery of some protected taxa • Range contractions and expansions • Loss of habitat diversity and complexity • Increase in variability , surprises, extreme events • This increases possibility of exceeding thresholds and increase likelihood of catastrophic and possibly irreversible events (e.g. 1998 global bleaching event) • Increasingly stressed and degraded ecosystems will be less resilient, more susceptible to change, disease, HAB, especially when cumulative human impacts occur. • We know stressors will increase in tropical zones where there is lot of biodiversity but lack of data

3. The Unknown of human drivers • Human population: • Trends of human migration (more or less in the coastal zone in developing countries) • Increasing urbanization having net benefits or harm on coastal environment. • Will technology transfer between developed countries and developing countries allow them to skip or speed through the same destruction the developed countries already have experienced? • Effectiveness of best management practices in controlling human impacts. • Complex interactions among human drivers: • synergistic effects, surprises, feed backs • thresholds • Identity of introduced species, diseases, HAB. • Link between human health and ecosystem “health”?

4. The Unknown impacts on diversity • Broad trends are known, but regional predictions are difficult (e.g. climate change) • How new mixes of species will interact • Evolutionary responses of species to change • Synergistic effects of increased variability and decreased resilience • Lag times of human impacts on species / ecosystems (i.e. nitrogen storage, pollutants in sediments) • Predictions of recovery vs. non-recovery, lots of surprises: e.g. slower than expected (Atlantic cod) or faster than expected (rockweed in the Baltic) some species recover from very reduced numbers (e.g. elephant seals) others don’t (Northern right whale) • Baselines as feasible goals for restoration and conservation? • Effects on cryptic species diversity

5. The Unknowable, and the significance of not knowing • Abrupt changes in people’s attitude and behavior towards the environment • Precise prediction of catastrophic events in space and time (storms, floods, disease, HAB, social disruption, economic disruption, …) • Significance: we have to live with dynamic ecosystems and uncertainties

6. Gaps in knowledge: what do we need to know and why • Cumulative effects of diverse drivers • Threshold and feedback effects

7. Is it possible to reverse the trajectory of degradation? • Cleanup of Baltic Sea • Recovery of sea otters, elephant seals in CA • Restoration of Swedish wetlands and saltmarshes