High and rising economic costs of biological invasions worldwide.

Biological invasions are responsible for substantial biodiversity declines as well as high economic losses to society and monetary expenditures associated with the management of these invasions1,2. The InvaCost database has enabled the generation of a reliable, comprehensive, standardized and easily updatable synthesis of the monetary costs of biological invasions worldwide3. Here we found that the total reported costs of invasions reached a minimum of US$1.288 trillion (2017 US dollars) over the past few decades (1970-2017), with an annual mean cost of US$26.8 billion. Moreover, we estimate that the annual mean cost could reach US$162.7 billion in 2017. These costs remain strongly underestimated and do not show any sign of slowing down, exhibiting a consistent threefold increase per decade. We show that the documented costs are widely distributed and have strong gaps at regional and taxonomic scales, with damage costs being an order of magnitude higher than management expenditures. Research approaches that document the costs of biological invasions need to be further improved. Nonetheless, our findings call for the implementation of consistent management actions and international policy agreements that aim to reduce the burden of invasive alien species.

Moving forward socio-economically focused models of deforestation.

Whilst high-resolution spatial variables contribute to a good fit of spatially explicit deforestation models, socio-economic processes are often beyond the scope of these models. Such a low level of interest in the socio-economic dimension of deforestation limits the relevancy of these models for decision-making and may be the cause of their failure to accurately predict observed deforestation trends in the medium term. This study aims to propose a flexible methodology for taking into account multiple drivers of deforestation in tropical forested areas, where the intensity of deforestation is explicitly predicted based on socio-economic variables. By coupling a model of deforestation location based on spatial environmental variables with several sub-models of deforestation intensity based on socio-economic variables, we were able to create a map of predicted deforestation over the period 2001-2014 in French Guiana. This map was compared to a reference map for accuracy assessment, not only at the pixel scale but also over cells ranging from 1 to approximately 600 sq. km. Highly significant relationships were explicitly established between deforestation intensity and several socio-economic variables: population growth, the amount of agricultural subsidies, gold and wood production. Such a precise characterization of socio-economic processes allows to avoid overestimation biases in high deforestation areas, suggesting a better integration of socio-economic processes in the models. Whilst considering deforestation as a purely geographical process contributes to the creation of conservative models unable to effectively assess changes in the socio-economic and political contexts influencing deforestation trends, this explicit characterization of the socio-economic dimension of deforestation is critical for the creation of deforestation scenarios in REDD+ projects.

Combining direct and indirect impacts to assess ecosystem service loss due to infrastructure construction.

The destruction of natural habitats and the associated loss of Ecosystem Services (ES) are rarely jointly assessed and quantified in Environmental Impact Assessment (EIA). Based on a terrestrial transport infrastructure project, the objective of this paper is to quantify the potential loss of ES associated with direct and indirect impacts, and illustrate their contribution to decision-making for route options. We first quantify how much of each type of ES is generated by different land units in the absence of the infrastructure (baseline conditions). We then estimate ES loss caused by infrastructure construction in a way that discriminates among different types of ES and losses because some ES, in addition to losses that are directly proportional to the surface impacted, can show additional indirect losses associated with landscape connectivity. In addition, we illustrate how the assessment of threshold effects in particular ecosystem types that may be most sensitive to their occurrence can affect the estimation of ES loss. We compare implementation options to provide an example of how choices can be improved by assessing ES loss associated with a combination of direct and indirect impacts. This kind of analysis could be used more generally to assess development projects simply by adapting the framework of analysis to the type of project and the ecosystems concerned.

The rising global economic costs of invasive Aedes mosquitoes and Aedes-borne diseases.

Invasive Aedes aegypti and Aedes albopictus mosquitoes transmit viruses such as dengue, chikungunya and Zika, posing a huge public health burden as well as having a less well understood economic impact. We present a comprehensive, global-scale synthesis of studies reporting these economic costs, spanning 166 countries and territories over 45 years. The minimum cumulative reported cost estimate expressed in 2022 US$ was 94.7 billion, although this figure reflects considerable underreporting and underestimation. The analysis suggests a 14-fold increase in costs, with an average annual expenditure of US$ 3.1 billion, and a maximum of US$ 20.3 billion in 2013. Damage and losses were an order of magnitude higher than investment in management, with only a modest portion allocated to prevention. Effective control measures are urgently needed to safeguard global health and well-being, and to reduce the economic burden on human societies. This study fills a critical gap by addressing the increasing economic costs of Aedes and Aedes-borne diseases and offers insights to inform evidence-based policy.

Questioning emissions-based approaches for the definition of REDD+ deforestation baselines in high forest cover/low deforestation countries.

BACKGROUND: REDD+ is being questioned by the particular status of High Forest/Low Deforestation countries. Indeed, the formulation of reference levels is made difficult by the confrontation of low historical deforestation records with the forest transition theory on the one hand. On the other hand, those countries might formulate incredibly high deforestation scenarios to ensure large payments even in case of inaction. RESULTS: Using a wide range of scenarios within the Guiana Shield, from methods involving basic assumptions made from past deforestation, to explicit modelling of deforestation using relevant socio-economic variables at the regional scale, we show that the most common methodologies predict huge increases in deforestation, unlikely to happen given the existing socio-economic situation. More importantly, it is unlikely that funds provided under most of these scenarios could compensate for the total cost of avoided deforestation in the region, including social and economic costs. CONCLUSION: This study suggests that a useful and efficient international mechanism should really focus on removing the underlying political and socio-economic forces of deforestation rather than on hypothetical result-based payments estimated from very questionable reference levels.

Massive yet grossly underestimated global costs of invasive insects.

Insects have presented human society with some of its greatest development challenges by spreading diseases, consuming crops and damaging infrastructure. Despite the massive human and financial toll of invasive insects, cost estimates of their impacts remain sporadic, spatially incomplete and of questionable quality. Here we compile a comprehensive database of economic costs of invasive insects. Taking all reported goods and service estimates, invasive insects cost a minimum of US$70.0 billion per year globally, while associated health costs exceed US$6.9 billion per year. Total costs rise as the number of estimate increases, although many of the worst costs have already been estimated (especially those related to human health). A lack of dedicated studies, especially for reproducible goods and service estimates, implies gross underestimation of global costs. Global warming as a consequence of climate change, rising human population densities and intensifying international trade will allow these costly insects to spread into new areas, but substantial savings could be achieved by increasing surveillance, containment and public awareness.

The seagrass Posidonia oceanica: Ecosystem services identification and economic evaluation of goods and benefits.

Posidonia oceanica is a marine angiosperm endemic from the Mediterranean. Despite their protection, its meadows are regressing. The economic valuation of ecosystem services (ES) assesses the contribution of ecosystems to human well-being and may provide local policy makers help in territorial development. To estimate the economic value of P. oceanica seagrass and the meadows that it forms to better account its presence in coastal development, identification and assessment of ES provided are first performed. Then goods and benefits (GB) and their economical values are estimated. In total, 25ES are identified and 7GB are economically evaluated. The economic value of GB provided by P. oceanica ranges between 25.3 million and 45.9 million€/year which means 283-513€/ha/year. Because of the lack of existing available data, only 7GB linked to 11/25ES have been estimated. Despite this overall undervaluation, this study offers a value for coastal development policies to take into account.

Valuing biodiversity and ecosystem services: Why put economic values on Nature?

The evaluation of ecosystems and biodiversity has become an important field of investigation for economists. Although their interest has been largely motivated by the search for arguments in favour of broader conservation policies, both the methods and the meaning of the results remain controversial. This article aims at clarifying the interest and limitations of these works, by revisiting a number of issues, such as the economic qualification of the services that human societies take from biodiversity and ecological systems in general, the specificities of their contribution to human well-being and the consequences of a valuation of biodiversity based on ecosystem services. We conclude with a discussion of the purposes of evaluations: improving public policies or creating new markets?