With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept ... more With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept of biodiversity hotspots has been useful in determining conservation priority areas. However, there has been limited research into how temporal variability in biodiversity may influence conservation area prioritization. To address this information gap, we present an approach to evaluate the temporal consistency of biodiversity hotspots in large marine ecosystems. Using a large scale, public monitoring dataset collected over an eight year period off the US Pacific Coast, we developed a methodological approach for avoiding biases associated with hotspot delineation. We aggregated benthic fish species data from research trawls and calculated mean hotspot thresholds for fish species richness and Shannon's diversity indices over the eight year dataset. We used a spatial frequency distribution method to assign hotspot designations to the grid cells annually. We found no areas containing consistently high biodiversity through the entire study period based on the mean thresholds, and no grid cell was designated as a hotspot for greater than 50% of the time-series. To test if our approach was sensitive to sampling effort and the geographic extent of the survey, we followed a similar routine for the northern region of the survey area. Our finding of low consistency in benthic fish biodiversity hotspots over time was upheld, regardless of biodiversity metric used, whether thresholds were calculated per year or across all years, or the spatial extent for which we calculated thresholds and identified hotspots. Our results suggest that static measures of benthic fish biodiversity off the US West Coast are insufficient for identification of hotspots and that long-term data are required to appropriately identify patterns of high temporal variability in biodiversity for these highly mobile taxa. Given that ecological communities are responding to a changing climate and other environmental perturbations, our work highlights the need for scientists and conservation managers to consider both spatial and temporal dynamics when designating biodiversity hotspots.
Two significant hydrocarbon spills have occurred in U.S. waters to date; the Exxon Valdez spill i... more Two significant hydrocarbon spills have occurred in U.S. waters to date; the Exxon Valdez spill in Prince William Sound, Alaska and the Deepwater Horizon blowout in the Gulf of Mexico. A review of the lessons learned and outcomes from these two deleterious events, in markedly differing geographic settings, offer unique insights into oil spill prevention and impacts to the in situ natural system. The differences between the two spills highlight the important role geographic setting plays on the severity of impacts and recovery of the local and regional ecosystem and economy. The lessons learned from both of these spills also offer key information to support science-based decision making for future spill prevention for a range of stakeholders. This paper reviews the environmental and economic impacts observed to highlight major differences between the two spills. Understanding how these trends and patterns affect impact severity and highlight knowledge/technology needs for each system provides critical information for research, managers, and decision makers especially as extreme offshore drilling increases in both the ultra-deepwater Gulf of Mexico and the offshore Arctic regions of the U.S.
Increasing interest in offshore hydrocarbon exploration has pushed the operational fronts associa... more Increasing interest in offshore hydrocarbon exploration has pushed the operational fronts associated with exploration efforts further offshore into deeper waters and more uncertain subsurface settings. This has become particularly common in the U.S. Gulf of Mexico. In this study we develop a spatial vulnerability approach and example assessment to support future spill prevention and improve future response readiness. This effort, which is part of a larger integrated assessment modeling spill prevention effort, incorporated economic and environmental data, and utilized a novel new oil spill simulation model from the U.S. Department of Energy's National Energy Technology Laboratory, the Blowout and Spill Occurrence Model (BLOSOM). Specifically, this study demonstrated a novel approach to evaluate potential impacts of hypothetical spill simulations at varying depths and locations in the northern Gulf of Mexico. The simulations are analyzed to assess spatial and temporal trends associated with the oil spill. The approach itself demonstrates how these data, tools and techniques can be used to evaluate potential spatial vulnerability of Gulf communities for various spill scenarios. Results of the hypothetical scenarios evaluated in this study suggest that under conditions like those simulated, a strong westward push by ocean currents and tides may increase the impacts of deep water spills along the Texas coastline, amplifying the vulnerability of communities on the local barrier islands. Ultimately, this approach can be used further to assess a range of conditions and scenarios to better understand potential risks and improve informed decision making for operators, responders, and stakeholders to support spill prevention as well as response readiness.
With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept ... more With the ongoing crisis of biodiversity loss and limited resources for conservation, the concept of biodiversity hotspots has been useful in determining conservation priority areas. However, there has been limited research into how temporal variability in biodiversity may influence conservation area prioritization. To address this information gap, we present an approach to evaluate the temporal consistency of biodiversity hotspots in large marine ecosystems. Using a large scale, public monitoring dataset collected over an eight year period off the US Pacific Coast, we developed a methodological approach for avoiding biases associated with hotspot delineation. We aggregated benthic fish species data from research trawls and calculated mean hotspot thresholds for fish species richness and Shannon's diversity indices over the eight year dataset. We used a spatial frequency distribution method to assign hotspot designations to the grid cells annually. We found no areas containing consistently high biodiversity through the entire study period based on the mean thresholds, and no grid cell was designated as a hotspot for greater than 50% of the time-series. To test if our approach was sensitive to sampling effort and the geographic extent of the survey, we followed a similar routine for the northern region of the survey area. Our finding of low consistency in benthic fish biodiversity hotspots over time was upheld, regardless of biodiversity metric used, whether thresholds were calculated per year or across all years, or the spatial extent for which we calculated thresholds and identified hotspots. Our results suggest that static measures of benthic fish biodiversity off the US West Coast are insufficient for identification of hotspots and that long-term data are required to appropriately identify patterns of high temporal variability in biodiversity for these highly mobile taxa. Given that ecological communities are responding to a changing climate and other environmental perturbations, our work highlights the need for scientists and conservation managers to consider both spatial and temporal dynamics when designating biodiversity hotspots.
Two significant hydrocarbon spills have occurred in U.S. waters to date; the Exxon Valdez spill i... more Two significant hydrocarbon spills have occurred in U.S. waters to date; the Exxon Valdez spill in Prince William Sound, Alaska and the Deepwater Horizon blowout in the Gulf of Mexico. A review of the lessons learned and outcomes from these two deleterious events, in markedly differing geographic settings, offer unique insights into oil spill prevention and impacts to the in situ natural system. The differences between the two spills highlight the important role geographic setting plays on the severity of impacts and recovery of the local and regional ecosystem and economy. The lessons learned from both of these spills also offer key information to support science-based decision making for future spill prevention for a range of stakeholders. This paper reviews the environmental and economic impacts observed to highlight major differences between the two spills. Understanding how these trends and patterns affect impact severity and highlight knowledge/technology needs for each system provides critical information for research, managers, and decision makers especially as extreme offshore drilling increases in both the ultra-deepwater Gulf of Mexico and the offshore Arctic regions of the U.S.
Increasing interest in offshore hydrocarbon exploration has pushed the operational fronts associa... more Increasing interest in offshore hydrocarbon exploration has pushed the operational fronts associated with exploration efforts further offshore into deeper waters and more uncertain subsurface settings. This has become particularly common in the U.S. Gulf of Mexico. In this study we develop a spatial vulnerability approach and example assessment to support future spill prevention and improve future response readiness. This effort, which is part of a larger integrated assessment modeling spill prevention effort, incorporated economic and environmental data, and utilized a novel new oil spill simulation model from the U.S. Department of Energy's National Energy Technology Laboratory, the Blowout and Spill Occurrence Model (BLOSOM). Specifically, this study demonstrated a novel approach to evaluate potential impacts of hypothetical spill simulations at varying depths and locations in the northern Gulf of Mexico. The simulations are analyzed to assess spatial and temporal trends associated with the oil spill. The approach itself demonstrates how these data, tools and techniques can be used to evaluate potential spatial vulnerability of Gulf communities for various spill scenarios. Results of the hypothetical scenarios evaluated in this study suggest that under conditions like those simulated, a strong westward push by ocean currents and tides may increase the impacts of deep water spills along the Texas coastline, amplifying the vulnerability of communities on the local barrier islands. Ultimately, this approach can be used further to assess a range of conditions and scenarios to better understand potential risks and improve informed decision making for operators, responders, and stakeholders to support spill prevention as well as response readiness.
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Papers by Jake R Nelson