James N. Sanchirico

Global economic potential for reducing carbon dioxide emissions from mangrove loss

Mangroves are among the most threatened and rapidly disappearing natural environments worldwide. In addition to supporting a wide range of other ecological and economic functions, mangroves store considerable carbon. Here, we consider the global economic potential for protecting mangroves based exclusively on their carbon. We develop unique high-resolution global estimates (5′ grid, about 9 × 9 km) of the projected carbon emissions from mangrove loss and the cost of avoiding the emissions. Using these spatial estimates, we derive global and regional supply curves (marginal cost curves) for avoided emissions. Under a broad range of assumptions, we find that the majority of potential emissions from mangroves could be avoided at less than

Coral reef habitats as surrogates of species, ecological functions, and ecosystem services

10 per ton of CO2. Given the recent range of market price for carbon offsets and the cost of reducing emissions from other sources, this finding suggests that protecting mangroves for their carbon is an economically viable proposition. Political-economy considerations related to the ability of doing business in developing countries, however, can severely limit the supply of offsets and increases their price per ton. We also find that although a carbon-focused conservation strategy does not automatically target areas most valuable for biodiversity, implementing a biodiversity-focused strategy would only slightly increase the costs.

Political economy of marine reserves: Understanding the role of opportunity costs

Habitat maps are often the core spatially consistent data set on which marine reserve networks are designed, but their efficacy as surrogates for species richness and applicability to other conservation measures is poorly understood. Combining an analysis of field survey data, literature review, and expert assessment by a multidisciplinary working group, we examined the degree to which Caribbean coastal habitats provide useful planning information on 4 conservation measures: species richness, the ecological functions of fish species, ecosystem processes, and ecosystem services. Approximately one-quarter to one-third of benthic invertebrate species and fish species (disaggregated by life phase; hereafter fish species) occurred in a single habitat, and Montastraea-dominated forereefs consistently had the highest richness of all species, processes, and services. All 11 habitats were needed to represent all 277 fish species in the seascape, although reducing the conservation target to 95% of species approximately halved the number of habitats required to ensure representation. Species accumulation indices (SAIs) were used to compare the efficacy of surrogates and revealed that fish species were a more appropriate surrogate of benthic species (SAI = 71%) than benthic species were for fishes (SAI = 42%). Species of reef fishes were also distributed more widely across the seascape than invertebrates and therefore their use as a surrogate simultaneously included mangroves, sea grass, and coral reef habitats. Functional classes of fishes served as effective surrogates of fish and benthic species which, given their ease to survey, makes them a particularly useful measure for conservation planning. Ecosystem processes and services exhibited great redundancy among habitats and were ineffective as surrogates of species. Therefore, processes and services in this case were generally unsuitable for a complementarity-based approach to reserve design. In contrast, the representation of species or functional classes ensured inclusion of all processes and services in the reserve network.

Evaluating the New Zealand Individual Transferable Quota Market For Fisheries Management

The creation of marine reserves is often controversial. For decisionmakers, trying to find compromises, an understanding of the timing, magnitude, and incidence of the costs of a reserve is critical. Understanding the costs, in turn, requires consideration of not just the direct financial costs but also the opportunity costs associated with reserves. We use a discrete choice model of commercial fishermen’s behavior to examine both the short-run and long-run opportunity costs of marine reserves. Our results can help policymakers recognize the factors influencing commercial fishermen’s responses to reserve proposals. More generally, we highlight the potential drivers behind the political economy of marine reserves.

Optimal approaches for balancing invasive species eradication and endangered species management

The New Zealand ITQ system is a dynamic institution that has had many refinements since its inception more than 15 years ago. Nonetheless, the basic tenets of the system - setting a total allowable catch and leaving the market to determine the most profitable allocation of fishing effort - have remained intact. This paper assesses the New Zealand system to identify areas of success and/or possible improvement or expansion within it. The reasons for doing so are to highlight beneficial features and to identify features of the New Zealand ITQ system that are relevant to other potential tradable permit markets. Beneficial features include simple standardized rules for quota definition and trading across species and areas; very few restrictions on quota trading and holding; relative stability in the rules over time; and low levels of government involvement in the trading process. We find evidence that supports the assertion that fishers behave in a reasonably rational fashion and that the markets are relatively efficient. We do not find major changes in participation in these fisheries as a result of the system. We find evidence that suggests that the ITQ system is improving the profitability of fisheries in New Zealand. In general the evidence thus far suggests that the market is operating in a reasonably efficient manner and is providing significant economic gains. These factors suggest that New Zealand would want to have non-economic justifications for any significant changes to the system.

Designing a Cost-Effective Marine Reserve Network: A Bioeconomic Metapopulation Analysis

Conservation vs. eradication Whats an ecologist to do when an endangered bird lives in an invasive grass? Ecosystems are complicated networks, with one species relying on another, and managing one species in isolation may damage other members of a community. Lampert et al. (see the Perspective by Buckley and Han) looked at the conflict between eradicating a damaging invasive grass species and protecting an endangered bird species that uses the grass as its home. The most effective management and restoration approach focused not on eradicating the invasive grass as quickly as possible but on making changes slowly enough that the birds could adapt. This approach may prove useful in other situations in which active restoration conflicts with other conservation goals. Science, this issue p. 1028; see also p. 975 Protecting endangered birds that nest in invasive grass requires a measured approach [Also see Perspective by Buckley and Han] Resolving conflicting ecosystem management goals—such as maintaining fisheries while conserving marine species or harvesting timber while preserving habitat—is a widely recognized challenge. Even more challenging may be conflicts between two conservation goals that are typically considered complementary. Here, we model a case where eradication of an invasive plant, hybrid Spartina, threatens the recovery of an endangered bird that uses Spartina for nesting. Achieving both goals requires restoration of native Spartina. We show that the optimal management entails less intensive treatment over longer time scales to fit with the time scale of natural processes. In contrast, both eradication and restoration, when considered separately, would optimally proceed as fast as possible. Thus, managers should simultaneously consider multiple, potentially conflicting goals, which may require flexibility in the timing of expenditures.

The effectiveness, costs and coastal protection benefits of natural and nature-based defences

Marine reserves are gaining attention around the world as a tool to both conserve ocean resources and improve the productivity of fisheries. Using simulation analysis, we investigate the inherent bioeconomic trade-offs in a limited-entry fishery associated with cost-effective designs of marine reserve networks—that is, the trade-offs between the degree of connectedness of a site and the biological and economic heterogeneity. We find in many cases that closing two low-value patches can result in larger biological gains and lower costs than closing one high-value patch. We also simulate biological productivity effects after creation of a reserve and find that under special conditions, aggregate sustainable rents are maximized with the closing of a portion of the fishable habitat. Finally, we find that the biological gains of implementing a more rationalized management system can outweigh the gains from closing multiple subpopulations under open access.

Mapping Ecosystem Functions to the Valuation of Ecosystem Services: Implications of Species-Habitat Associations for Coastal Land-Use Decisions

There is great interest in the restoration and conservation of coastal habitats for protection from flooding and erosion. This is evidenced by the growing number of analyses and reviews of the effectiveness of habitats as natural defences and increasing funding world-wide for nature-based defences–i.e. restoration projects aimed at coastal protection; yet, there is no synthetic information on what kinds of projects are effective and cost effective for this purpose. This paper addresses two issues critical for designing restoration projects for coastal protection: (i) a synthesis of the costs and benefits of projects designed for coastal protection (nature-based defences) and (ii) analyses of the effectiveness of coastal habitats (natural defences) in reducing wave heights and the biophysical parameters that influence this effectiveness. We (i) analyse data from sixty-nine field measurements in coastal habitats globally and examine measures of effectiveness of mangroves, salt-marshes, coral reefs and seagrass/kelp beds for wave height reduction; (ii) synthesise the costs and coastal protection benefits of fifty-two nature-based defence projects and; (iii) estimate the benefits of each restoration project by combining information on restoration costs with data from nearby field measurements. The analyses of field measurements show that coastal habitats have significant potential for reducing wave heights that varies by habitat and site. In general, coral reefs and salt-marshes have the highest overall potential. Habitat effectiveness is influenced by: a) the ratios of wave height-to-water depth and habitat width-to-wavelength in coral reefs; and b) the ratio of vegetation height-to-water depth in salt-marshes. The comparison of costs of nature-based defence projects and engineering structures show that salt-marshes and mangroves can be two to five times cheaper than a submerged breakwater for wave heights up to half a metre and, within their limits, become more cost effective at greater depths. Nature-based defence projects also report benefits ranging from reductions in storm damage to reductions in coastal structure costs.

Secure sustainable seafood from developing countries

Habitats and the ecosystem services they provide are part of the world’s portfolio of natural capital assets. Like many components of this portfolio, it is difficult to assess the full economic value of these services, which tends to over-emphasize the value of extractive activities such as coastal development. Building on recent ecological studies of species–habitat linkages, we use a bioeconomic model to value multiple types of habitats as natural capital, using mangroves, sea grass, and coral reefs as our model system. We show how key ecological variables and processes, including obligate and facultative behaviors map into habitat values and how the valuation of these ecological processes can inform decisions regarding coastal development (habitat clearing). Our stylized modeling framework also provides a clear and concise road map for researchers interested in understanding how to make the link between ecosystem function, ecosystem service, and conservation policy decisions. Our findings also highlight the importance of additional ecological research into how species utilize habitats and that this research is not just important for ecological science, but it can and will influence ecosystem service values that, in turn, will impact coastal land-use decisions. While refining valuation methods is not necessarily going to lead to more rational coastal land-use decisions, it will improve our understanding on the ecological–economic mechanisms that contribute to the value of our natural capital assets.

Use of Incentive-Based Management Systems to Limit Bycatch and Discarding

Require improvements as conditions for market access Demand for sustainably certified wild-caught fish and crustaceans is increasingly shaping global seafood markets. Retailers such as Walmart in the United States, Sainsburys in the United Kingdom, and Carrefour in France, and processors such as Canadianbased High Liner Foods, have promised to source all fresh, frozen, farmed, and wild seafood from sustainable sources by 2015 (1, 2). Credible arbiters of certifications, such as the Marine Stewardship Council (MSC), require detailed environmental and traceability standards. Although these standards have been met in many commercial fisheries throughout the developed world (3), developing country fisheries (DCFs) represent only 7% of ~220 total MSC-certified fisheries (4, 5). With the United Nations Food and Agriculture Organization reporting that developing countries account for ~50% of seafood entering international trade, this presents a fundamental challenge for marketers of sustainable seafood (see the photo).