UC Santa Barbara

People around the world depend on healthy oceans for sustenance, employment, culture, and identity, among other valuable ecosystem services. Anthropogenic impacts from human activity on land and sea, coupled with increasing effects of climate change, drive declines in the health of marine biodiversity throughout the world’s oceans, which puts at risk those ecosystem services we value. Effective marine conservation efforts depend on understanding where and to what degree anthropogenic stressors are impacting marine ecosystems. In this dissertation, my colleagues and I catalogued and compared the activities and stressors contributing to marine biodiversity loss, noting those stressors imposing the greatest impacts and those for which risk of impact is poorly understood. We then mapped the footprint of cumulative impacts across ranges of 1,271 threatened and near-threatened marine species on a global scale from 2003 to 2013. We found that on average, species are substantially affected by human stressors across more than half their range, and these impact footprints expanded in scale and increased in intensity over the study period. Building upon a trait-based framework for estimating species vulnerability to human stressors, we expanded our mapping methodology to 21,267 marine animal species, examining patterns of impact through lenses of species richness, functional vulnerability, and representative habitats. I conclude by examining the current literature on applying machine learning methods to estimate species conservation status based on information on species traits, stressors, and environmental conditions. Using a value of information framework, I explore the improvement in expected outcome of conservation management decision based on incorporating additional predictor data or increasing the number of species used to train the model. The resulting conceptual model can help identify optimal investment in data collection and formal assessment of currently data-deficient species to accelerate our understanding of extinction risk of marine biodiversity. In all, the concepts and methods presented here can inform effective, equitable, and ecologically representative conservation efforts toward the goals proposed in the draft of the United Nations Convention on Biological Diversity Post-2020 Global Biodiversity Framework.