Environmental Systems Analysis Group

Many marine invertebrate species facing potential extinction have uncertain taxonomies and poorly known demographic and ecological traits. Uncertainties are compounded when potential extinction drivers are climate and ocean changes whose effects on even widespread and abundant species are only partially understood. The U.S. Endangered Species Act mandates conservation management decisions founded on the extinction risk to species based on the best available science at the time of consideration—requiring prompt action rather than awaiting better information. We developed an expert-opinion threat-based approach that entails a structured voting system to assess extinction risk from climate and ocean changes and
other threats to 82 coral species for which population status and threat response information was limited. Such methods are urgently needed because constrained budgets and manpower will continue to hinder the availability of desired data for many potentially vulnerable marine species. Significant species-specific information gaps and uncertainties precluded quantitative assessments of habitat loss or population declines and necessitated increased reliance on demographic characteristics and threat vulnerabilities at genus or family levels. Adapting some methods (e.g., a structured voting system) used during other assessments and developing some new approaches (e.g., integrated assessment of threats and demographic characteristics), we rated the importance of threats contributing to coral extinction risk and assessed those threats against population status and trend information to evaluate each species’ extinction risk over the 21st century. This qualitative assessment resulted in a ranking with an uncertainty range for each species according to their estimated likelihood of extinction. We offer guidance on approaches for future biological extinction risk assessments, especially in cases of data-limited species likely to be affected by global-scale threats.

Determining whether a species warrants listing as threatened or endangered under the U.S. Endangered Species Act depends on the government's assessment of the species’ extinction risk, usually in response to a petition. Deciding whether data are sufficient to make a listing determination is a challenging part of the process. We examined three case studies involving corals. A petition for deep-sea corals was rejected for full status review of the species, based on insufficient information on population trends and threats. Information on threats for 82 tropical corals was sufficient to propose listing of 66 species. Significant population declines and identified threats resulted in listing two Atlantic Acropora corals as ‘Threatened’. There was no decrease in journal publication rate on the Acropora species after that listing, and no decrease in research permit applications in marine protected areas. However, the effects of listings on research that might help to sustain or recover species remains largely unknown.

Marine conservation efforts are often focused on increasing stocks of species with low population abundances by reducing mortality or enhancing recruitment. However, global changes in climate and ocean chemistry are density-independent factors that can strongly affect corals whether they are scarce or abundant—sometimes, the abundant corals are most affected. Because reproductive corals are sessile, density-independent effects of global changes such as physiological stress and resultant mortality can decouple stock abundance from recruitment and may accelerate the downward spiral of their reproductive rates.

Determining whether a species warrants listing as threatened or endangered under the U.S. Endangered Species Act depends on the government's assessment of the species' extinction risk, usually in response to a petition. Deciding whether data are sufficient to make a listing determination is a challenging part of the process. We examined three case studies involving corals. A petition for deep-sea corals was rejected for full status review of the species, based on insufficient information on population trends and threats. Information on threats for 82 tropical corals was sufficient to propose listing of 66 species. Significant population declines and identified threats resulted in listing two Atlantic Acropora corals as 'Threatened'. There was no decrease in journal publication rate on the Acropora species after that listing, and no decrease in research permit applications in marine protected areas. However, the effects of listings on research that might help to sustain or recover species remains largely unknown.

Three trophic mass-balance models representing coral reef ecosystems along a fishery gradient were compared to evaluate ecosystem effects of fishing. The majority of the biomass estimates came directly from a large-scale visual survey program; therefore, data were collected in the same way for all three models, enhancing comparability. Model outputs-such as net system production, size structure of the community, total throughput, production, consumption, production-to-respiration ratio, and Finn's cycling index and mean path length-indicate that the systems around the unpopulated French Frigate Shoals and along the relatively lightly populated Kona Coast of Hawai'i Island are mature, stable systems with a high efficiency in recycling of biomass. In contrast, model results show that the reef system around the most populated island in the State of Hawai'i, O'ahu, is in a transitional state with reduced ecosystem resilience and appears to be shifting to an algaldominated system. Evaluation of the candidate indicators for fishing pressure showed that indicators at the community level (e.g., total biomass, community size structure, trophic level of the community) were most robust (i.e., showed the clearest trend) and that multiple indicators are necessary to identify fishing perturbations. These indicators could be used as performance indicators when compared to a baseline for management purposes. This study shows that ecosystem models can be valuable tools in identification of the system state in terms of complexity, stability, and resilience and, therefore, can complement biological metrics currently used by monitoring programs as indicators for coral reef status. Moreover, ecosystem models can improve our understanding of a system's internal structure that can be used to support management in identification of approaches to reverse unfavorable states.

Determining whether a species warrants listing as threatened or endangered under the U.S. Endangered Species Act depends on the government's assessment of the species’ extinction risk, usually in response to a petition. Deciding whether data are sufficient to make a listing determination is a challenging part of the process. We examined three case studies involving corals. A petition for deep-sea corals was rejected for full status review of the species, based on insufficient information on population trends and threats. Information on threats for 82 tropical corals was sufficient to propose listing of 66 species. Significant population declines and identified threats resulted in listing two Atlantic Acropora corals as ‘Threatened’. There was no decrease in journal publication rate on the Acropora species after that listing, and no decrease in research permit applications in marine protected areas. However, the effects of listings on research that might help to sustain or recove...

Marine conservation efforts are often focused on increasing stocks of species with low population abundances by reducing mortality or enhancing recruitment. However, global changes in climate and ocean chemistry are density-independent factors that can strongly affect corals whether they are scarce or abundant—sometimes, the abundant corals are most affected. Because reproductive corals are sessile, density-independent effects of global changes such as physiological stress and resultant mortality can decouple stock abundance from recruitment and may accelerate the downward spiral of their reproductive rates.

Wide-scale and sudden shifts in several biological and environmental systems of NW Europe have been reported in recent years, and attributed to a range of factors, both climatic and anthropogenic. To examine whether there is any evidence of coinciding region-wide environmental shifts, we gathered existing long-term data series on a wide range of physical and biological parameters from the 1960s to the present and, following the methods of a similar recent study on North Pacific regime shifts, we analysed the data using principal component analysis and regime shift analysis to identify the extent and timing of regime shifts in NW Europe. The end-point of a regime (i.e. the year) was determined using a sliding window in regime shift analysis. Additionally we applied chronological clustering to the (1) combined data, (2) biological data and (3) environmental data. In all 3 cases, the same regimes were identified. Our results indicate that substantial regime shifts occurred in the marine ecosystem in 1979 and 1988 and perhaps also in 1998, although results were less clear-cut in the latter case. These regime shifts were most evident among the biological data series, but they appeared to have been triggered by earlier shifts in a number of environmental factors. Salinity and weather conditions played an important role in the 1979 shift, while in the 1988 shift, temperature and weather conditions were the predominant factors. Our results confirm those of the North Pacific study, with concomitant changes in physical and biological indices. This indicates a shift in climate-ocean interactions throughout the entire temperate zone of the Northern Hemisphere.

Three trophic mass-balance models representing coral reef ecosystems along a fishery gradient were compared to evaluate ecosystem effects of fishing. The majority of the biomass estimates came directly from a large-scale visual survey program; therefore, data were collected in the same way for all three models, enhancing comparability. Model outputs–such as net system production, size structure of the community, total throughput, production, consumption, production-to-respiration ratio, and Finn's cycling index and mean path length–indicate that the systems around the unpopulated French Frigate Shoals and along the relatively lightly populated Kona Coast of Hawai'i Island are mature, stable systems with a high efficiency in recycling of biomass. In contrast, model results show that the reef system around the most populated island in the State of Hawai'i, O'ahu, is in a transitional state with reduced ecosystem resilience and appears to be shifting to an algal-dominated system. Evaluation of the candidate indicators for fishing pressure showed that indicators at the community level (e.g., total biomass, community size structure, trophic level of the community) were most robust (i.e., showed the clearest trend) and that multiple indicators are necessary to identify fishing perturbations. These indicators could be used as performance indicators when compared to a baseline for management purposes. This study shows that ecosystem models can be valuable tools in identification of the system state in terms of complexity, stability, and resilience and, therefore, can complement biological metrics currently used by monitoring programs as indicators for coral reef status. Moreover, ecosystem models can improve our understanding of a system's internal structure that can be used to support management in identification of approaches to reverse unfavorable states.

Ecosystem modelling is increasingly used to explore ecosystem-level effects of changing environmental conditions and management actions. For coral reefs there has been increasing interest in recent decades in the use of ecosystem models for evaluating the effects of fishing and the efficacy of marine protected areas. However, ecosystem models that integrate physical forcings, biogeochemical and ecological dynamics, and human induced perturbations are still underdeveloped. We applied an ecosystem model (Atlantis) to the coral reef ecosystem of Guam using a suite of management scenarios prioritized in consultation with local resource managers to review the effects of each scenario on performance measures related to the ecosystem, the reef-fish fishery (e.g., fish landings) and coral habitat. Comparing tradeoffs across the selected scenarios showed that each scenario performed best for at least one of the selected performance indicators. The integrated 'full regulation' scenario outperformed other scenarios with four out of the six performance metrics at the cost of reef-fish landings. This model application quantifies the socio-ecological costs and benefits of alternative management scenarios. When the effects of climate change were taken into account, several scenarios performed equally well, but none prevented a collapse in coral biomass over the next few decades assuming a business-as-usual greenhouse gas emissions scenario.

Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) bio-mass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers, generally meaning that declines in ecosystem metrics are not as steep as the sum of individual effects of the drivers. These analyses offer one way to quantify impacts

Coral reefs are increasingly threatened despite being essential to coastal and island economies, particularly in the Pacific. The diving industry relies on healthy reefs and can be positively and/or negatively impacted by ecological change. Quantifying divers' ecological preferences that influence economic outcomes can help inform managers and justify conservation. Utilizing non-market valuation, we assess SCUBA divers' preferences for ecological attributes of coral reef ecosystems in Guam, estimate WTP for coastal and watershed management, and investigate drivers influencing preferences. A discrete choice experiment grounded in ecosystem modeling reveals divers prefer reefs with greater ecological health (higher fish biomass, diversity, and charismatic species). Individuals with stronger environmental values expressed stronger ecological preferences. Fish biomass improvement from low (b25 g/m 2) to high (N 60 g/m 2) was worth N$2 million/year. The presence of sharks and turtles together was the preeminent attribute, worth $15–20 million/year. Divers are willing to voluntarily contribute ($900thousand) towards watershed sediment-reduction projects that could benefit divers by improving reef conditions. Few policies are in place worldwide collecting fees from divers for coral reef management, and none in Guam. Our results suggest that understanding divers' preferences and the drivers behind them may assist managers in designing policies that capture divers WTP and create partners in conservation.