Systematic nature positive markets.

Environmental markets are a rapidly emerging tool to mobilize private funding to incentivize landholders to undertake more sustainable land management. How units of biodiversity in these markets are measured and subsequently traded creates key challenges ecologically and economically because it determines whether environmental markets can deliver net gains in biodiversity and efficiently lower the costs of conservation. We developed and tested a metric for such markets based on the well-established principle of irreplaceability from systematic conservation planning. Irreplaceability as a metric avoids the limitations of like-for-like trading and allows one to capture the multidimensional nature of ecosystems (e.g., habitats, species, ecosystem functioning) and simultaneously achieve cost-effective, land-manager-led investments in conservation. Using an integrated ecological modeling approach, we tested whether using irreplaceability as a metric is more ecologically and economically beneficial than the simpler biodiversity offset metrics typically used in net gain and no-net-loss policies. Using irreplaceability ensured no net loss, or even net gain, of biodiversity depending on the targets chosen. Other metrics did not provide the same assurances and, depending on the flexibility with which biodiversity targets can be achieved, and how they overlap with development pressure, were less efficient. Irreplaceability reduced the costs of offsetting to developers and the costs of ecological restoration to society. Integrating economic data and systematic conservation planning approaches would therefore assure land managers they were being fairly rewarded for the opportunity costs of conservation and transparently incentivize the most ecologically and economically efficient investments in nature recovery.

Mercados sistemáticos que favorecen a la naturaleza Resumen Los mercados ambientales se están convirtiendo rápidamente en una herramienta para movilizar el financiamiento privado que incentiva a los terratenientes a realizar un manejo de suelo más sustentable. La forma de medir las unidades de biodiversidad y su intercambio subsecuente en estos mercados genera retos ecológicos y económicos importantes pues determina si el mercado ambiental puede generar ganancias netas de biodiversidad y reducir eficientemente el costo de la conservación. Desarrollamos y probamos una medida para dichos mercados con base en el principio bien establecido del carácter irremplazable tomado de la planeación sistemática de la conservación. Si se usa como medida, este carácter evita las limitantes del comercio en términos comparables y permite que se capture la naturaleza multidimensional de los ecosistemas (p. ej.: hábitats, especies, funcionamiento) y a la vez consigue inversiones rentables llevadas por el gestor para la conservación. Usamos una estrategia de modelado ecológico integrado para probar si usar el carácter irremplazable como medida tiene más beneficios ecológicos y económicos que las medidas más simples de compensación de la biodiversidad que se usan comúnmente en las políticas sin pérdida neta y de ganancia neta. El uso del carácter irremplazable aseguró que no hubiera pérdida neta o incluso ganancia neta de la biodiversidad según el objetivo elegido. Las otras medidas no proporcionaron la misma seguridad y fueron menos eficientes según la flexibilidad con la cual se logran los objetivos de biodiversidad y cómo se traslapan con la presión del desarrollo. El carácter irremplazable redujo los costos de la compensación para los desarrolladores y los costos de la restauración ecológica para la sociedad. Por lo tanto, la integración de los datos económicos y las estrategias de planeación sistemática de la conservación les asegurarían a los gestores de los terrenos que se les está compensando de manera justa por los costos de oportunidad de conservación e incentivaría con transparencia las inversiones con mayor eficiencia ecológica y económica en la recuperación de la naturaleza.

Ecological and economic implications of alternative metrics in biodiversity offset markets.

Policy tools are needed that allow reconciliation of human development pressures with conservation priorities. Biodiversity offsetting can be used to compensate for ecological losses caused by development activities. Landowners can choose to undertake conservation actions, including habitat restoration, to generate biodiversity offsets. Consideration of the incentives facing landowners as potential biodiversity offset providers and developers as potential buyers of credits is critical when considering the ecological and economic landscape-scale outcomes of alternative offset metrics. There is an expectation that landowners will always seek to conserve the least profitable land parcels, and, in turn, this determines the spatial location of biodiversity offset credits. We developed an ecological-economic model to compare the ecological and economic outcomes of offsetting for a habitat-based metric and a species-based metric. We were interested in whether these metrics would adequately capture the indirect benefits of offsetting on species not considered under a no-net-loss policy. We simulated a biodiversity offset market for a case study landscape, linking species distribution modeling and an economic model of landowner choice based on economic returns of the alternative land management options (restore, develop, or maintain existing land use). Neither the habitat nor species metric adequately captured the indirect benefits of offsetting on related habitats or species. The underlying species distributions, layered with the agricultural and development rental values of parcels, resulted in very different landscape outcomes depending on the metric chosen. If policy makers are aiming for the metric to act as an indicator to mitigate impacts on a range of closely related habitats and species, then a simple no-net-loss target is not adequate. Furthermore, to achieve the most ecologically beneficial design of offsets policy, an understanding of the economic decision-making processes of the landowners is needed.

Se necesitan herramientas políticas que permitan la reconciliación entre las presiones del desarrollo humano y las prioridades de conservación. La compensación de biodiversidad puede usarse para reponer las pérdidas ecológicas causadas por las actividades de desarrollo. Los terratenientes pueden elegir realizar acciones de conservación, incluyendo la restauración del hábitat, para generar dichas compensaciones. Es importante considerar los incentivos para los terratenientes como proveedores potenciales de compensaciones de biodiversidad y para los desarrolladores como compradores potenciales de créditos cuando se contemplan los resultados ecológicos y económicos a escala de paisaje de estas medidas alternativas de compensación. Existe la expectativa de que los terratenientes siempre buscarán conservar los lotes menos rentables y, por lo tanto, esto determina la ubicación espacial de los créditos por compensación de biodiversidad. Desarrollamos un modelo para comparar los resultados ecológicos y económicos de la compensación en una medida basada en el hábitat y una basada en la especie. Nos interesaba saber si estas medidas indicarían adecuadamente los beneficios indirectos de la compensación para las especies no consideradas bajo una política de pérdida neta cero. Simulamos un mercado voluntario de biodiversidad para un estudio de casode un paisaje, el cual vinculó el modelado de la distribución de especies con el modelo económico de las elecciones de los terratenientes basadas en las ganancias económicas de las opciones alternativas de manejo de suelo (restaurar, desarrollar o mantener el uso de suelo existente). Ninguna de las dos medidas indicó adecuadamente los beneficios indirectos de la compensación para las especies o hábitats relacionados. La distribución subyacente de especies, en conjunto con los valores de renta agrícolas y de desarrollo de los lotes, derivó en resultados muy diferentes de paisaje según la medida seleccionada. Cuando los formuladores de políticas buscan que la medida actúe como un indicador para mitigar impactos en una gama de especies y hábitats relacionados cercanamente, no es adecuado un objetivo simple de pérdida neta cero. Además, para lograr el diseño con el mayor beneficio ecológico, se requiere comprender los procesos de decisión de los terratenientes.

Non-monetary numeraires: Varying the payment vehicle in a choice experiment for health interventions in Uganda.

Schistosomiasis is a serious health problem in many parts of Africa which is linked to poor water quality and limited sanitation resources. We administered a discrete choice experiment on water access and health education in rural Uganda, focussing on interventions designed to reduce cases of the disease. Unlike previous studies, we included a payment vehicle of both labour hours supplied per week and money paid per month within each choice set. We were thus able to elicit both willingness to pay and willingness to work for alternative interventions. Respondents exhibit high demand for new water sources. From the random parameter model, only households with knowledge about water-borne parasites are price sensitive and exhibit willingness to pay values. Through a latent class model specification, higher income respondents exhibit higher willingness to pay values for all programme attributes; however, lower income participants have higher willingness to work values for certain new water sources. We found a shadow wage rate of labour that is between 15 and 55% of the market wage rate.

The Effects of Disease on Optimal Forest Rotation: A Generalisable Analytical Framework.

The arrival of novel pathogens and pests can have a devastating effect on the market values of forests. Calibrating management strategies/decisions to consider the effect of disease may help to reduce disease impacts on forests. Here, we use a novel generalisable, bioeconomic model framework, which combines an epidemiological compartmental model with a Faustmann optimal rotation length model, to explore the management decision of when to harvest a single rotation, even-aged, plantation forest under varying disease conditions. Sensitivity analysis of the rate of spread of infection and the effect of disease on the timber value reveals a key trade-off between waiting for the timber to grow and the infection spreading further. We show that the optimal rotation length, which maximises the net present value of the forest, is reduced when timber from infected trees has no value; but when the infection spreads quickly, and the value of timber from infected trees is non-zero, it can be optimal to wait until the disease-free optimal rotation length to harvest. Our original approach provides an exemplar framework showing how a bioeconomic model can be used to examine the effect of tree diseases on management strategies/decisions.

Payment for multiple forest benefits alters the effect of tree disease on optimal forest rotation length.

Forests deliver multiple benefits both to their owners and to wider society. However, a wave of forest pests and pathogens is threatening this worldwide. In this paper we examine the effect of disease on the optimal rotation length of a single-aged, single rotation forest when a payment for non-timber benefits, which is offered to private forest owners to partly internalise the social values of forest management, is included. Using a generalisable bioeconomic framework we show how this payment counteracts the negative economic effect of disease by increasing the optimal rotation length, and under some restrictive conditions, even makes it optimal to never harvest the forest. The analysis shows a range of complex interactions between factors including the rate of spread of infection and the impact of disease on the value of harvested timber and non-timber benefits. A key result is that the effect of disease on the optimal rotation length is dependent on whether the disease affects the timber benefit only compared to when it affects both timber and non-timber benefits. Our framework can be extended to incorporate multiple ecosystem services delivered by forests and details of how disease can affect their production, thus facilitating a wide range of applications.

The effects of invasive pests and pathogens on strategies for forest diversification.

Diversification of the tree species composition of production forests is a frequently advocated strategy to increase resilience to pests and pathogens; however, there is a lack of a general framework to analyse the impact of economic and biological conditions on the optimal planting strategy in the presence of tree disease. To meet this need we use a novel bioeconomic model to quantitatively assess the effect of tree disease on the optimal planting proportion of two tree species. We find that diversifying the species composition can reduce the economic loss from disease even when the benefit from the resistant species is small. However, this key result is sensitive to a pathogen's characteristics (probability of arrival, time of arrival, rate of spread of infection) and the losses (damage of the disease to the susceptible species and reduced benefit of planting the resistant species). This study provides an exemplar framework which can be used to help understand the effect of a pathogen on forest management strategies.

User fees across ecosystem boundaries: Are SCUBA divers willing to pay for terrestrial biodiversity conservation?

While ecological links between ecosystems have been long recognised, management rarely crosses ecosystem boundaries. Coral reefs are susceptible to damage through terrestrial run-off, and failing to account for this within management threatens reef protection. In order to quantify the extent to that coral reef users are willing to support management actions to improve ecosystem quality, we conducted a choice experiment with SCUBA divers on the island of Bonaire, Caribbean Netherlands. Specifically, we estimated their willingness to pay to reduce terrestrial overgrazing as a means to improve reef health. Willingness to pay was estimated using the multinomial, random parameter and latent class logit models. Willingness to pay for improvements to reef quality was positive for the majority of respondents. Estimates from the latent class model determined willingness to pay for reef improvements of between $31.17 - $413.18/year, dependent on class membership. This represents a significant source of funding for terrestrial conservation, and illustrates the potential for user fees to be applied across ecosystem boundaries. We argue that such across-ecosystem-boundary funding mechanisms are an important avenue for future investigation in many connected systems.

Do we care about sustainability? An analysis of time sensitivity of social preferences under environmental time-persistent effects.

Environmental cost-benefit analysis has traditionally assumed that the value of benefits is sensitive to their timing and that outcomes are valued higher, the sooner in time they occur following implementation of a project or policy. Though, this assumption might have important implications especially for the social desirability of interventions aiming at counteracting time-persistent environmental problems, whose impacts occur in the long- and very long-term, respectively involving the present and future generations. This study analyzes the time sensitivity of social preferences for preservation policies of adaptation to climate change stresses. Results show that stated preferences are time insensitive, due to sustainability issues: individuals show insignificant differences in benefits they can experience within their own lifetimes compared to those which occur in the longer term, and which will instead be enjoyed by future generations. Whilst these results may be specific to the experimental design employed here, they do raise interesting questions regarding choices over time-persistent environmental problems, particularly in terms of the desirability of interventions which produce longer-term benefits.

Trophy hunters' willingness to pay for wildlife conservation and community benefits.

In the face of fundamental land-use changes, the potential for trophy hunting to contribute to conservation is increasingly recognized. Trophy hunting can, for example, provide economic incentives to protect wildlife populations and their habitat, but empirical studies on these relationships are few and tend to focus on the effects of benefit-sharing schemes from an ex post perspective. We investigated the conditions under which trophy hunting could facilitate wildlife conservation in Ethiopia ex ante. We used a choice experiment approach to survey international trophy hunters' (n = 224) preferences for trips to Ethiopia, here operationalized as trade-offs between different attributes of a hunting package, as expressed through choices with an associated willingness to pay. Participants expressed strong preferences and, consequently, were willing to pay substantial premiums for hunting trips to areas with abundant nontarget wildlife where domestic livestock was absent and for arrangements that offered benefit sharing with local communities. For example, within the range of percentages considered in the survey, respondents were on average willing to pay an additional $3900 for every 10 percentage points of the revenue being given to local communities. By contrast, respondents were less supportive of hunting revenue being retained by governmental bodies: Willingness to pay decreased by $1900 for every 10 percentage points of the revenue given to government. Hunters' preferences for such attributes of hunting trips differed depending on the degree to which they declared an interest in Ethiopian culture, nature conservation, or believed Ethiopia to be politically unstable. Overall, respondents thus expressly valued the outcomes of nature conservation activities--the presence of wildlife in hunting areas--and they were willing to pay for them. Our findings highlight the usefulness of insights from choice modeling for the design of wildlife management and conservation policies and suggest that trophy hunting in Ethiopia could generate substantially more financial support for conservation and be more in line with conservation objectives than is currently the case.

La Disposición de los Cazadores de Trofeos a Pagar por la Conservación de la Vida Silvestre y los Beneficios de la Comunidad Resumen De frente a los cambios fundamentales en el uso de suelo, el potencial de que la caza de trofeos contribuya a la conservación es reconocido cada vez más. Este tipo de caza puede, por ejemplo, proporcionar incentivos económicos para proteger poblaciones de vida silvestre y su hábitat, pero los estudios empíricos sobre estas relaciones son pocos y tienden a enfocarse en los efectos de los esquemas de compartir beneficios desde una perspectiva ex post. Investigamos las condiciones bajo las cuales la caza de trofeos podría facilitar la conservación de vida silvestre en Etiopía de forma ex ante. Usamos una estrategia de experimento de opciones para encuestar a cazadores internacionales de trofeos (n = 224) sobre sus preferencias por viajes a Etiopía, usados aquí como compensaciones entre los diferentes atributos de un paquete de caza, expresadas a través de opciones con una disposición asociada a pagar. Los participantes expresaron fuertes preferencias y, en consecuencia, estaban dispuestos a pagar primas sustanciales por viajes de caza a áreas con abundantes especies no cazadas y donde el ganado doméstico estaba ausente, y por arreglos que ofrecían compartir beneficios con la comunidad local. Por ejemplo, dentro del rango de porcentajes considerados en la encuesta, los respondientes estaban, en promedio, dispuestos a pagar unos $3900 adicionales por cada 10 puntos porcentuales de los ingresos que se otorgan a la comunidad local. En contraste, los respondientes no apoyaron la idea de que el gobierno retenga los ingresos: la disposición a pagar disminuyó en $1900 por cada 10 puntos porcentuales de los ingresos otorgados al gobierno. Las preferencias de los cazadores por dichos atributos de los viajes de caza difirieron dependiendo del grado al cual declararon un interés por la cultura etíope, la conservación de la naturaleza o su creencia en la inestabilidad política de Etiopía. En general, los respondientes así valoraron explícitamente los resultados de las actividades de conservación de la naturaleza - la presencia de vida silvestre en áreas de caza - y su disposición a pagar por ellos. Nuestros hallazgos resaltan la utilidad de percepción a partir del modelado de opciones para el diseño de planes de manejo de vida silvestre y políticas de conservación y sugieren que la caza de trofeos en Etiopía puede generar sustancialmente más apoyo financiero para la conservación y estar más en línea con los objetivos de conservación que los planes de manejo actuales.

Can macrophyte harvesting from eutrophic water close the loop on nutrient loss from agricultural land?

Eutrophication is a major water pollution issue and can lead to excessive growth of aquatic plant biomass (APB). However, the assimilation of nutrients into APB provides a significant target for their recovery and reuse, and harvesting problematic APB in impacted freshwater bodies offers a complementary approach to aquatic restoration, which could potentially deliver multiple wider ecosystem benefits. This critical review provides an assessment of opportunities and risks linked to nutrient recovery from agriculturally impacted water-bodies through the harvesting of APB for recycling and reuse as fertilisers and soil amendments. By evaluating the economic, social, environmental and health-related dimensions of this resource recovery from 'waste' process we propose a research agenda for closing the loop on nutrient transfer from land to water. We identify that environmental benefits are rarely, if ever, prioritised as essential criteria for the exploitation of resources from waste and yet this is key for addressing the current imbalance that sees environmental managers routinely undervaluing the wider environmental benefits that may accrue beyond resource recovery. The approach we advocate for the recycling of 'waste' APB nutrients is to couple the remediation of eutrophic waters with the sustainable production of feed and fertiliser, whilst providing multiple downstream benefits and minimising environmental trade-offs. This integrated 'ecosystem services approach' has the potential to holistically close the loop on agricultural nutrient loss, and thus sustainably recover finite resources such as phosphorus from waste.

Valuing the commons: An international study on the recreational benefits of the Baltic Sea.

The Baltic Sea provides benefits to all of the nine nations along its coastline, with some 85 million people living within the catchment area. Achieving improvements in water quality requires international cooperation. The likelihood of effective cooperation is known to depend on the distribution across countries of the benefits and costs of actions needed to improve water quality. In this paper, we estimate the benefits associated with recreational use of the Baltic Sea in current environmental conditions using a travel cost approach, based on data from a large, standardized survey of households in each of the 9 Baltic Sea states. Both the probability of engaging in recreation (participation) and the number of visits people make are modeled. A large variation in the number of trips and the extent of participation is found, along with large differences in current annual economic benefits from Baltic Sea recreation. The total annual recreation benefits are close to 15 billion EUR. Under a water quality improvement scenario, the proportional increases in benefits range from 7 to 18% of the current annual benefits across countries. Depending on how the costs of actions are distributed, this could imply difficulties in achieving more international cooperation to achieve such improvements.

Quantifying preferences for the natural world using monetary and nonmonetary assessments of value.

Given that funds for biodiversity conservation are limited, there is a need to understand people's preferences for its different components. To date, such preferences have largely been measured in monetary terms. However, how people value biodiversity may differ from economic theory, and there is little consensus over whether monetary metrics are always appropriate or the degree to which other methods offer alternative and complementary perspectives on value. We used a choice experiment to compare monetary amounts recreational visitors to urban green spaces were willing to pay for biodiversity enhancement (increases in species richness for birds, plants, and aquatic macroinvertebrates) with self-reported psychological gains in well-being derived from visiting the same sites. Willingness-to-pay (WTP) estimates were significant and positive, and respondents reported high gains in well-being across 3 axes derived from environmental psychology theories (reflection, attachment, continuity with past). The 2 metrics were broadly congruent. Participants with above-median self-reported well-being scores were willing to pay significantly higher amounts for enhancing species richness than those with below-median scores, regardless of taxon. The socio-economic and demographic background of participants played little role in determining either their well-being or the probability of choosing a paying option within the choice experiment. Site-level environmental characteristics were only somewhat related to WTP, but showed strong associations with self-reported well-being. Both approaches are likely to reflect a combination of the environmental properties of a site and unobserved individual preference heterogeneity for the natural world. Our results suggest that either metric will deliver mutually consistent results in an assessment of environmental preferences, although which approach is preferable depends on why one wishes to measure values for the natural world.

Self-reported benefits and risks of open water swimming to health, wellbeing and the environment: Cross-sectional evidence from a survey of Scottish swimmers.

Engaging with natural environments benefits human health by providing opportunities for social interactions, enhancing mental wellbeing and enabling outdoor spaces for physical exercise. Open water swimming has seen a rapid increase in popularity, partly due to the physical health benefits it can provide but also with the growing interest in (re)connecting with nature for environment-health interactions. Using a national-scale online survey of 717 open water swimmers, the aim of this study was to investigate patterns and trends in the perceived benefits and risks of open water swimming to both public health and the environment; and to understand whether these perceived risks and benefits vary across different typologies of swimmers and open water, or 'blue space', environments. Strong associations were found between the most important self-reported benefit associated with open water swimming and both participant age and the categorisation of their typical swim style. All but one of the age-groups surveyed perceived mental wellbeing benefits to be the most important benefit of open water swimming; whilst those aged over 65 identified physical rather than mental wellbeing benefits to be the most important outcome. Participants who preferred lake swimming reported greater concern regarding possible environmental damage caused by the increasing popularity of open water swimming compared to those engaging in river or sea swimming. However, the majority of participants perceived the risks to the environment from open water swimming to be minimal. Our study adds to the growing evidence that open water swimming is perceived by participants as benefitting their mental and physical wellbeing. Improved understanding of the benefits and risks of engaging with blue spaces used for open water swimming can contribute to co-designed policy development to promote safer, healthier and more sustainable outdoor recreation opportunities associated with this increasingly popular outdoor pursuit.

Farmers' valuation and willingness to pay for vaccines to protect livestock resources against priority infectious diseases in Ghana.

INTRODUCTION: Livestock vaccination coverage rates remain low in many lower and middle income countries despite effective vaccines being commonly available. Consequently, many preventable infectious livestock diseases remain highly prevalent, causing significant animal mortalities and threatening farmers' livelihood and food security. This study sought to assess farmers' maximum willingness to pay (WTP) for contagious bovine pleuropneumonia (CBPP), and peste-des-petits-ruminants (PPR) vaccination of cattle, and sheep and goats, respectively. METHODS: Overall, 350 ruminant livestock farmers were randomly selected from three districts located in the northern, middle and southern farming belts of Ghana. We implemented a double-bounded dichotomous contingent valuation experiment, where farmers indicated their WTP for vaccinating each livestock specie(s) owned at randomly assigned price points. WTP responses were analyzed using maximum likelihood estimation, and factors influencing WTP were assessed using censored regression analysis accounting for village-level clustering. RESULTS: Mean WTP for CBPP vaccination was USD 1.43 or Ghanaian Cedi (GHC) 8.63 (95% CI: GHC 7.08-GHC 10.19) per cattle. Mean WTP for PPR vaccination was USD 1.17 or GHC 7.02 (95% CI: GHC 5.99-GHC 8.05) per sheep, and USD 1.1 or GHC 6.66 (95% CI: GHC 5.89-GHC 7.44) per goat. WTP was positively associated with resilience, limited knowledge about vaccines (assessed prior to WTP experiment), farmland size, and male gender, after adjusting for other covariates. To attain 70% vaccination coverage in Ghana, vaccination costs should be no larger than GHC 5.30 (USD 0.88) for CBPP per cattle and GHC 3.89 (USD 0.65) and GHC 3.67 (USD 0.61), respectively, for PPR vaccines per sheep and goat. CONCLUSIONS: Ruminant livestock farmers in Ghana value vaccination highly, and are, on average, willing to pay vaccination costs that exceed the prevailing market prices (GHC 6 for CBPP and GHC 5 for PPR vaccination) to protect their livestock resources. To achieve 70% coverage, only minor subsidies would likely be required. These results suggest that effective disease control in these settings should be possible with appropriate distribution strategies.

The cost of policy simplification in conservation incentive programs.

Incentive payments to private landowners provide a common strategy to conserve biodiversity and enhance the supply of goods and services from ecosystems. To deliver cost-effective improvements in biodiversity, payment schemes must trade-off inefficiencies that result from over-simplified policies with the administrative burden of implementing more complex incentive designs. We examine the effectiveness of different payment schemes using field parameterized, ecological economic models of extensive grazing farms. We focus on profit maximising farm management plans and use bird species as a policy-relevant indicator of biodiversity. Common policy simplifications result in a 49-100% loss in biodiversity benefits depending on the conservation target chosen. Failure to differentiate prices for conservation improvements in space is particularly problematic. Additional implementation costs that accompany more complicated policies are worth bearing even when these constitute a substantial proportion (70% or more) of the payments that would otherwise have been given to farmers.

Challenges of integrating economics into epidemiological analysis of and policy responses to emerging infectious diseases.

COVID-19 has shown that the consequences of a pandemic are wider-reaching than cases and deaths. Morbidity and mortality are important direct costs, but infectious diseases generate other direct and indirect benefits and costs as the economy responds to these shocks: some people lose, others gain and people modify their behaviours in ways that redistribute these benefits and costs. These additional effects feedback on health outcomes to create a complicated interdependent system of health and non-health outcomes. As a result, interventions primarily intended to reduce the burden of disease can have wider societal and economic effects and more complicated and unintended, but possibly not anticipable, system-level influences on the epidemiological dynamics themselves. Capturing these effects requires a systems approach that encompasses more direct health outcomes. Towards this end, in this article we discuss the importance of integrating epidemiology and economic models, setting out the key challenges which such a merging of epidemiology and economics presents. We conclude that understanding people's behaviour in the context of interventions is key to developing a more complete and integrated economic-epidemiological approach; and a wider perspective on the benefits and costs of interventions (and who these fall upon) will help society better understand how to respond to future pandemics.

Increasing the cost-effectiveness of nutrient reduction targets using different spatial scales.

In this paper, we investigate the potential gains in cost-effectiveness from changing the spatial scale at which nutrient reduction targets are set for the Baltic Sea, with particular focus on nutrient loadings from agriculture. The costs of achieving loading reductions are compared across five levels of spatial scale, namely the entire Baltic Sea; the marine basin level; the country level; the watershed level; and the grid square level. A novel highly-disaggregated model, which represents decreases in agricultural profits, changes in root zone N concentrations and transport to the Baltic Sea is used. The model includes 14 Baltic Sea marine basins, 14 countries, 117 watersheds and 19,023 10-by-10 km grid squares. The main result which emerges is that there is a large variation in the total cost of the program depending on the spatial scale of targeting: for example, for a 40% reduction in loads, the costs of a Baltic Sea-wide target is nearly three times lower than targets set at the smallest level of spatial scale (grid square). These results have important implications for both domestic and international policy design for achieving water quality improvements where non-point pollution is a key stressor of water quality.

Field-level bird abundances are enhanced by landscape-scale agri-environment scheme uptake.

Despite two decades of agri-environment schemes (AESs) aimed at mitigating farmland biodiversity losses, the evidence that such programmes actually benefit biodiversity remains limited. Using field-level surveys, we assess the effectiveness of AESs in enhancing bird abundances in an upland area of England, where schemes have been operating for over 20 years. In such a region, the effects of AESs should be readily apparent, and we predict that bird abundances will co-vary with both field- and landscape-scale measures of implementation. Using an information theoretic approach, we found that, for abundances of species of conservation concern and upland specialists, measures of AES implementation and habitat type at both scales appear in the most parsimonious models. Field-level bird abundances are higher where more of the surrounding landscape is included in an AES. While habitat remains a more influential predictor, we suggest that landscape-scale implementation results in enhanced bird abundances. Hence, measures of the success of AESs should consider landscape-wide benefits as well as localized impacts.

Spontaneous divergence of disease status in an economic epidemiological game.

We introduce a game inspired by the challenges of disease management in livestock farming and the transmission of endemic disease through a trade network. Success in this game comes from balancing the cost of buying new stock with the risk that it will be carrying some disease. When players follow a simple memory-based strategy we observe a spontaneous separation into two groups corresponding to players with relatively high, or low, levels of infection. By modelling the dynamics of both the disease and the formation and breaking of trade relationships, we derive the conditions for which this separation occurs as a function of the transmission rate and the threshold level of acceptable disease for each player. When interactions in the game are restricted to players that neighbour each other in a small-world network, players tend to have similar levels of infection as their neighbours. We conclude that success in economic-epidemiological systems can originate from misfortune and geographical circumstances as well as by innate differences in personal attitudes towards risk.

Freshwater blue space and population health: An emerging research agenda.

Growing evidence suggests that access and exposure to water bodies or blue spaces can provide a variety of health and well-being benefits. Attempts to quantify these 'blue-health' benefits have largely focused on coastal environments, with freshwater blue spaces receiving far less attention despite over 50% of the global population living within 3 km of a body of freshwater and populations living in landlocked areas having limited coastal access. This critical review identifies opportunities to improve our understanding of the relationship between freshwater blue space and health and well-being and outlines key recommendations to broaden the portfolio of emerging research needs associated with the field of blue-health. Recognising fundamental distinctions in relationships between health outcomes and access and exposure to freshwater versus coastal blue space is critical and further research is required to determine the mechanisms that link exposure to freshwater blue space with tangible health outcomes and to understand how such mechanisms vary across a range of freshwater environments. Furthermore, methodological improvements are necessary as spatial approaches adopted to quantify access and exposure to freshwater blue space often fail to account for the unique physical characteristics of freshwater and come with a variety of limitations. Based on the findings of this review, a suite of research needs are proposed, which can be categorised into three broad themes: (i) establishing a freshwater blue-health methodological framework; (ii) advancing the empirical freshwater blue-health evidence base; and (iii) promoting freshwater blue-health opportunities. When taken together, these research themes offer opportunities to advance current understanding and better integrate freshwater blue space into the wider nature-health research agenda.