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The loss of maize landraces is of major global concern. Landraces provide the genetic building blocks for the development of high yielding pest- and drought-tolerant maize varieties, and their loss reduces the capacity to adapt to changing environmental conditions. The extinction of maize landraces is an incidental effect of the planting decisions of farmers. Although maize landraces are important both as a staple food and the source of traditional specialty foods required in particular cultural events and ceremonies, they are frequently displaced by high-yielding cultivars. The study considers the factors influencing on-farm maize diversity in the Lacandon tropical forest in the Mexican state of Chiapas. Using a censored regression model fitted with cross-sectional household farmer data, the factors behind crop choices was investigated, paying particular attention to the relation between crop diversity, wealth, and income transfers. It was found that maize diversity bears a non-monotonic relation to wealth, but is positively associated with both agricultural subsidies and poverty support. Key words: Crop choice, crop diversity, Lacandon forest, maize diversity, poverty, on-farm conservation, Mexico, censored regression.

We consider the effect of emission charges on market structure, output, and emissions in Cournot competition. Assuming myopic decision making and a partial adjustment process, we analyze the impact of emission charges on the stability of duopoly/monopoly and on the level of emissions. We show that where marginal emission charges are increasing in the level of emissions, duopoly is stable. However, where marginal emission charges are decreasing in emissions, duopoly is unstable, and the system converges on monopoly. Equilibrium output and emissions are also shown to be higher under cost structures favoring monopoly than under cost structures favoring duopoly.

Land conversion and the resulting contact between domesticated and wild species has arguably been the single largest contributor to the emergence of novel epizootic and zoonotic diseases in the past century. An unintended consequence of these interactions is zoonotic or epizootic disease spillovers from wild species to humans and their domesticates. Disease spillovers are edge effects of land conversion and are sensitive to the size and shape of converted areas. We combine spatial metrics from landscape ecology with theoretical epidemiological models to understand how the size and shape of land conversion affect epizootic and zoonotic disease transmission of single and two species populations. We show that the less compact the converted area, and the the greater the depth of the contact zone, the more rapidly will an introduced disease spread through the domesticated population.

The network of international environmental agreements (IEAs) has been characterized as a complex adaptive system (CAS) in which the uncoordinated responses of nation states to changes in the conditions addressed by particular agreements may generate seemingly coordinated patterns of behavior at the level of the system. Unfortunately, since the rules governing national responses are ill understood, it is not currently possible to implement a CAS approach. Polarization of both political parties and the electorate has been implicated in a secular decline in national commitment to some IEAs, but the causal mechanisms are not clear. In this paper, we explore the impact of polarization on the rules underpinning national responses. We identify the degree to which responsibility for national decisions is shared across political parties and calculate the electoral cost of party positions as national obligations under an agreement change. We find that polarization typically affects the degree but not the direction of national responses. Whether national commitment to IEAs strengthens or weakens as national obligations increase depends more on the change in national obligations than on polarization per se. Where the rules governing national responses are conditioned by the current political environment, so are the dynamic consequences both for the agreement itself and for the network to which it belongs. Any CAS analysis requires an understanding of such conditioning effects on the rules governing national responses.

Chapter 11 focuses on protected areas. It considers how the principles developed in earlier chapters inform protected area design—especially their size, shape, and expected duration—and management. It covers the ecological principles involved (threat, distinctness, and representativeness), and their connection to the theory of island biogeography. It then discusses how these are modified by economic principles requiring that the benefits of protection need to offset the opportunities forgone by committing resources to the acquisition of the necessary rights, the additional cost of conservation effort, and the net costs to those impacted by the change in rights. It is shown how evaluation of the trade-offs involved makes it possible to identify the optimal size of individual protected areas, or the optimal structure of a network of protected areas.

Chapter 5 introduces the concept of value, and the methods used to obtain estimates of the value of scarce environmental goods and services—particularly the provision, cultural, and regulating ecosystem services. It discusses the concept of social opportunity cost, and shows how the concept informs our understanding of the trade-offs involved in application of the equimarginal principle. It clarifies the relation between the income and substitution effects of changes in value, compensating and equivalent variation, and the willingness to pay or willingness to accept. Valuation methods discussed include both revealed preference (travel cost, averting behavior, hedonic price, production function, replacement cost) and stated preference (contingent valuation, contingent behavior, choice modeling) approaches. The valuation of biodiversity is approached through the regulating ecosystem services, using a portfolio approach to the management of uncertainty. The chapter shows how managers may select which species to conserve so as to balance environmental risk and the benefits from ecosystems.

Chapter 12 considers the conservation problem outside of protected areas, and how it reflects the principles described earlier. Topics addressed include the conservation of endangered wild species in unprotected areas and especially in agricultural areas; the in situ protection of the genetic diversity of livestock strains, crops, and crop wild relatives; and the ex situ protection of germ-plasm in zoos, arboreta, and seed banks. Protection of wild species on private lands covers the maintenance of habitat remnants important to the survival of endangered species, and the establishment and maintenance of biocorridors between habitats important to the survival of endangered species. Protection of domesticated species on agricultural and forestland covers the genetic erosion and genetic vulnerability of cultivated species that has followed the widespread adoption of high-yielding varieties.

Chapter 3 explores the Hotelling theory of conservation. It shows how the Hotelling arbitrage condition provides a test for whether it is optimal to convert or conserve a resource in some state. If the value of a resource when conserved is expected to grow faster than its value when converted, it will be optimal to conserve it. The chapter shows how the arbitrage condition applies to both nonrenewable and renewable resources, and how it is embodied in the conditions required for the optimal conversion/conservation of natural resources of both kinds. It also introduces Hamiltonian methods commonly used to optimize natural resource management, and shows the relation between Lagrangian and Hamiltonian methods. Finally, it discusses the relation between Hotelling conservation and the methods applied in conservation biology.

Many of the environmental changes that threaten biodiversity are negative externalities of agriculture, forestry, industrial production, infrastructural development, and urban growth. Examples include climate change, habitat loss and fragmentation, and the spread of pests and pathogens. Chapter 9 considers the nature of environmental externalities: whether they are public or private, whether unidirectional or reciprocal, and how they relate to wider environmental and socioeconomic conditions. It also considers the instruments available to internalize externalities at different scales, either by confronting those whose actions harm others with the full cost of the actions, or by compensating those whose actions confer benefits on others. Instruments discussed include the assignment of property rights, regulations and legal controls, and economic instruments such as pollution charges or payments for ecosystem services.

The conservation of ecosystems that either span national jurisdictions or extend beyond areas of national jurisdiction requires the establishment of governance mechanisms that operate above national governments, and hence that involve some cession of national sovereignty. This involves the coordination of national action, usually through the negotiation of bilateral or multilateral agreements. Chapter 14 considers the problem of conservation across national jurisdictions, focusing on ecosystems that span jurisdictions, migratory species, and the international movement of pests and pathogens as an incidental effect of trade and travel. It explores the impact of strategic behavior on the effectiveness of multilateral agreements, and the institutions developed to supply transboundary public goods such as climate mitigation.

Since the 1993 Convention on Biological Diversity, nation-states have asserted sovereign rights over all biological resources within their boundaries. Chapter 13 reviews the policies and instruments applied by governments to the conservation of natural capital in areas of national jurisdiction. Measures addressed include the assignment of property rights in biological resources; protective legislation; environmental offsets; incentive systems including taxes, subsidies, and payments for ecosystem services; and penalties. Particular attention is paid to common pool resource management regimes, legal restrictions on land use such as the US Endangered Species Act, biodiversity offsets, and payment systems such as the EU and US agri-environment schemes.

Chapter 7 considers the substitutability between produced and natural capital—assets used in the production of goods and services, and between environmental and other goods and services. It shows the ways in which the limits of substitutability are captured in both production and utility functions, and what this means for conservation. The chapter also discusses the relation between substitutability and the value of environmental inputs, using concepts of gross substitutability and complementarity, and the elasticity of substitution. The authors also note that the relative value of environmental inputs is frequently dependent on the environmental conditions under which production takes place.

Chapter 1 introduces the content and structure of the book. It identifies the main characteristics of the Hotelling approach to conservation, and the nature of the conservation problems it can address. It summarizes the evidence for large-scale, systematic changes in biodiversity and ecological functioning across biomes. It identifies what elements of the biophysical system have and have not been conserved, how this differs from one society to the next, and what has been gained or lost in the process. Finally, the chapter also discusses the different ways in which the conservation problem has been analyzed by natural and social scientists.

Chapter 10 addresses the relation between conservation, income, and wealth, focusing on the problem of biodiversity. It reconsiders the current consensus that poverty alleviation will reduce biodiversity loss. It addresses three dimensions of the problem: the role of income in the demand for natural resources; the empirical relation between income and biodiversity conservation; and the link between wealth, property rights, and the incentive to conserve. The first connects poverty, population growth, and the demand for natural resources. The second shows how biodiversity conservation and per capita income are related. The third connects poverty and property rights. It shows that for rural landholders to have an incentive to conserve their land, they also need to have secure rights. A necessary condition for land conservation to be optimal by the Hotelling principle is that the rights-holder can realize the gains to be had from conserving the resource.

Chapter 2 reviews key elements of decision theory as applied to the management of environmental resources. It illustrates the principles governing economic decisions generally, especially the equimarginal principle, and shows how these principles guide trade-offs between goods and services consumed by individuals or communities, or between inputs employed by households, firms, or public enterprises. It identifies the elements of decision problems involving constrained optimization, and shows how these elements appear in problems involving the conservation of scarce resources. It also introduces Lagrangian methods for the optimization of constrained decision problems, and provides an initial treatment of the role of discounting in decisions involving time.

Chapter 8 considers the conservation of environmental public goods. The nonexclusive and nonrival nature of public goods provide an incentive to free-ride on the efforts of others. The result is that such public goods are systematically undervalued and the underlying environmental assets—such as watersheds, habitats, and ecological communities—are underconserved. It shows how individuals determine their contribution to public goods (via a Nash-Cournot reaction curve), and compares the result to the contribution that would be made if resources were being allocated efficiently from the perspective of society. Types of environmental public goods considered include additive (climate change), best- and better-shot (defence), weakest- and weaker-link (infectious disease control), and local public goods (common pool resources). The chapter also shows how strategic behavior by the beneficiaries of public goods may lead to socially undesirable outcomes (such as prisoner’s dilemmas).

Chapter 6 examines the value of environmental assets, which lies in the discounted stream of services they offer. Their conservation depends on the expected rate of change in their value, if conserved, relative to the rate of return on alternative assets. This chapter considers how the portfolio of environmental assets—natural capital—has been valued at the national scale. The two main approaches adopted are the United Nations’ System of Environmental-Economic Accounts (SEEA), and the World Bank’s (Inclusive) Wealth Accounts. The authors consider both approaches, and what they mean for the sustainability and the efficiency of natural resource use. Particular attention is paid to the residual left over after taking account of all marketed inputs in production: total factor productivity.

Biodiversity is declining worldwide, and the costs of biodiversity losses are increasingly being recognized by economists. In this article, we first review the multiple meanings of biodiversity, moving from species richness and simple abundance-weighted species counts to more complex measures that take account of taxonomic distance and functionality. We then explain the ways in which protecting biodiversity generates economic benefits in terms of direct and indirect values. Empirical approaches to estimating direct and indirect values are presented, along with a selection of recent evidence on how substantial these values are. The use of asset accounting approaches to track biodiversity values over time is discussed, in the context of sustainable development paths. Finally, we review some important challenges in valuing biodiversity that remain to be solved.

Mick Common, who helped establish and define Ecological Economics, died on July 9 in Glasgow, Scotland. He was 78, and is survived by his wife Branwen and daughters Jane and Stephanie.

The growth in world trade has generated significant benefits to humankind, but it has also generated costs. Among these is an increase in the dispersal of pests and pathogens across the globe. International trade has been implicated in outbreaks of several re-occurring livestock diseases. This paper is focused on the risk of foot and mouth disease (FMD) associated with the international trade in live animals. A model was used to estimate FMD risk as a function of the international trade in live animals, controlling for the biosecurity measures undertaken by importing and exporting countries, and for the presence of endemic FMD reservoirs. It was found that the indirect risks associated with exports may be as great as the direct risks associated with imports. For countries where livestock production occurs in disease-free zones (with or without vaccination), the trade risks vary with both species and trading partner. These findings may assist the targeting of disease risk mitigation activities.

The term tragedy of the commons is widely used to describe the overexploitation of open access common pool resources. Open access allows potential resource users to continue to enter the resource up to the point where rents are exhausted. The resulting level of resource use is higher than the socially optimal level. In extreme cases, unlimited entry can lead to the collapse of the resource and the communities that depend on it. In this paper we use potential games to analyze the relation between costs of entry, costs of production, and the equilibrium number of resource users in open access regimes. We find that costs of access and costs of production determine the equilibrium number of resource users. We also find a natural link between Cournot competition and the tragedy of the commons. We discuss the relation between common pool resource management regimes and cost structure and show that cost structures are sufficient to determine the number of resource users accessing the resource.

Does society benefit from encouraging or discouraging private infectious disease-risk mitigation? Private individuals routinely mitigate infectious disease risks through the adoption of a range of precautions, from vaccination to changes in their contact with others. Such precautions have epidemiological consequences. Private disease-risk mitigation generally reduces both peak prevalence of symptomatic infection and the number of people who fall ill. At the same time, however, it can prolong an epidemic. A reduction in prevalence is socially beneficial. Prolongation of an epidemic is not. We find that for a large class of infectious diseases, private risk mitigation is socially suboptimal—either too low or too high. The social optimum requires either more or less private mitigation. Since private mitigation effort depends on the cost of mitigation and the cost of illness, interventions that change either of these costs may be used to alter mitigation decisions. We model the potential for instruments that affect the cost of illness to yield net social benefits. We find that where a disease is not very infectious or the duration of illness is short, it may be socially optimal to promote private mitigation effort by increasing the cost of illness. By contrast, where a disease is highly infectious or long lasting, it may be optimal to discourage private mitigation by reducing the cost of disease. Society would prefer a shorter, more intense, epidemic to a longer, less intense epidemic. There is, however, a region in parameter space where the relationship is more complicated. For moderately infectious diseases with medium infectious periods, the social optimum depends on interactions between prevalence and duration. Basic reproduction numbers are not sufficient to predict the social optimum.

A “cap and trade” style system for managing whale harvests represents a potentially useful approach to resolve the current gridlock in international whale management. The establishment of whale permit markets, open to both whalers and conservationists, could reveal the strength of conservation demand. However, while much is known about demand for whale-based products there is uncertainty about demand for conservation and the willingness of conservation interests to engage in the market. This makes it difficult to predict the outcome of a hypothetical whale permit market. As a thought experiment, we develop a bioeconomic model to evaluate the influence of economic uncertainty about demand for whale conservation or harvest. We use simulations over a wide range of parameterizations of whaling and conservation demands to examine the potential ecological consequences of the establishment of a whale permit market in Norwegian waters under bounded (but substantial) economic uncertainty. We find that while a whale conservation market has the potential to yield a wide range of conservation and harvest outcomes, the most likely outcomes are those in which conservationists buy all whale permits. This article is protected by copyright. All rights reserved

This paper investigates the impact of change in sectoral water supply on employment, value-added output, and indirect business tax, in Maricopa County, Arizona using input–output model. We developed extended modified input–output approach that incorporates each source of water as a separate sector, and that allows for substitution between water sources, and estimated the economic impact of a change in surface water supplies under two scenarios. Scenario I assumes that total water supply/use decreases by 1%, but the reduction comes only from surface water use, holding groundwater use constant. Scenario II assumes that surface water supply/use in all industries decreases by 1%, and the reduction in surface water use is replaced by the exact amount of more expensive groundwater. We found that the magnitude of economic impact depends on consumer’s responsiveness to water price change. When price elasticity of water demand is relatively low (≤0.2), the economic impact of a 1% reduction in surface water...

Highly pathogenic avian influenza (HPAI) H5N1 has led to the death or destruction of millions of domesticated and wild birds and caused hundreds of human deaths worldwide. As with other HPAIs, H5N1 outbreaks among poultry have generally been caused by contact with infected migratory waterfowl at the interface of wildlands and human-dominated landscapes. Using a case–control epidemiological approach, we analyzed the relation between habitat protection and H5N1 outbreaks in China from 2004 to 2017. We found that while proximity to unprotected waterfowl habitats and rice paddy generally increased outbreak risk, proximity to the most highly protected habitats (e.g., Ramsar-designated lakes and wetlands) had the opposite effect. Protection likely involves two mechanisms: the separation of wild waterfowl and poultry populations and the diversion of wild waterfowl from human-dominated landscapes toward protected natural habitats. Wetland protection could therefore be an effective means to control avian influenza while also contributing to avian conservation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13280-019-01238-2) contains supplementary material, which is available to authorized users.

The National Seed Strategy for Rehabilitation and Restoration aims to increase the use of native seeds in rehabilitation and restoration projects. This requires the development of a native seed supply industry. This paper examines the challenge of developing native seed supply for Bureau of Land Management (BLM) land holdings in the Colorado Plateau, USA. On the demand side of the market, native seed requirements are linked to events that trigger the need for restoration, such as wildfires, which are highly variable. The variability of demand is moderated somewhat by fire management and seed acquisition policies, but remains high. Acquisitions of native seeds are typically smaller in quantity and more variable than acquisitions of non-native seeds. Prices of native seeds are typically higher and more variable than prices of non-native seeds, while the price elasticity of demand for native seeds is typically lower than for non-native seeds. The variability of demand for native seeds has discouraged development of a native seed supply industry. We find that adoption of policies to stabilize demand, supported by contracts with growers, could help to encourage the emergence of a strong field-grown native seed sector in the Colorado Plateau.

One of the main physical effects of the depletion of aquifers is land subsidence – the lowering of the land-surface elevation as a result of groundwater overdraft. A second effect is the development of earth fissures as a result of the horizontal movement of sediments during subsidence. To determine the value of these effects we investigated the impact of land subsidence and earth fissures on residential property values in Maricopa County, Arizona. Using 82,716 arms-length property sales between 2004 and 2010, we estimated a fixed effects hedonic price model. We found that existing and future land subsidence, and earth fissures had a negative impact on the property values. The mean value of properties located in land subsidence features was lower than those located outside land subsidence features, and the disamenity associated with earth fissures was largest for properties located in land subsidence features.

Three interrelated world trends may be exacerbating emerging zoonotic risks: income growth, urbanization, and globalization. Income growth is associated with rising animal protein consumption in developing countries, which increases the conversion of wild lands to livestock production, and hence the probability of zoonotic emergence. Urbanization implies the greater concentration and connectedness of people, which increases the speed at which new infections are spread. Globalization-the closer integration of the world economy-has facilitated pathogen spread among countries through the growth of trade and travel. High-risk areas for the emergence and spread of infectious disease are where these three trends intersect with predisposing socioecological conditions including the presence of wild disease reservoirs, agricultural practices that increase contact between wildlife and livestock, and cultural practices that increase contact between humans, wildlife, and livestock. Such an intersection occurs in China, which has been a "cradle" of zoonoses from the Black Death to avian influenza and SARS. Disease management in China is thus critical to the mitigation of global zoonotic risks.

More than two-thirds of all wild capture marine fish stocks are currently being exploited at or beyond the maximum sustainable yield. Many coastal systems, including the mangrove forests and coral reefs that serve as fish nurseries, have been severely depleted through coastal habitat conversion and land-based emissions. Nutrient runoff is responsible for an increasing number of dead zones—areas of the ocean so depleted of oxygen that they cannot sustain life. Reasons for this include the facts (a) that many ocean resources are effectively open access (b) that markets fail to signal the true scarcity of many marine resources, and (c) that governments fail either to protect against or to correct for the inability of markets to allocate resources. This paper considers the problems of overexploitation and pollution of marine systems, and reviews the impact of institutions on each problem. It then discusses the options for reform.

Economic Growth, Human Development, and Welfare" of the 2018 Report of the International Panel on Social Progress (IPSP). Mission of the IPSP: The International Panel on Social Progress (IPSP) will harness the competence of hundreds of experts about social issues and will deliver a report addressed to all social actors, movements, organizations, politicians and decision-makers, in order to provide them with the best expertise on questions that bear on social change. The Panel will seek consensus whenever possible but will not hide controversies and will honestly present up-to-date arguments and analyses, and debates about them, in an accessible way. The Panel will have no partisan political agenda, but will aim at restoring hope in social progress and stimulating intellectual and public debates. Different political and philosophical views may conceive of social progress in different ways, emphasizing values such as freedom, dignity, or equality. The Panel will retain full independence from political parties, governments, and organizations with a partisan agenda. While the Panel will primarily work for the dissemination of knowledge to all relevant actors in society, it will also foster research on the topics it will study and help to revive interest for research in social long-term prospective analysis

One effect of the Green Revolution has been the displacement of landraces and traditional livestock strains. Although humankind has historically cultivated more than 7000 species, 15 crops now provide 90% of the world’s food energy intake. The shift from traditional to modern production systems has led to genetic erosion of many crop species, and to the disappearance of a number of landraces—plants that are morphologically distinct, have some genetic integrity but are also genetically variable and dynamic, and have distinctive properties in terms of yield, date of maturity, pest and disease resistance. The paper evaluates the effects of genetic erosion on wealth. Local wealth effects stem from the role of landraces and wild crop relatives in managing environmental risk, especially in the least developed countries. Global wealth effects stem from the fact that loss of genetic resources reduces our capacity to adapt to environmental (especially climate) change. Using the conservation principle implicit in the Hotelling arbitrage condition, it will consider the efficiency and equity implications of genetic erosion in agriculture and forestry and will address the particular conservation challenge posed by the need for genetically dynamic crop resources to be conserved in situ.