Vaissière A.C., Quétier F., Bierry A., Vannier C., Baptist F., Lavorel S. (2021), Modeling Alternative Approaches to the Biodiversity Offsetting of Urban Expansion in the Grenoble Area (France): What Is the Role of Spatial Scales in ‘No Net Loss’ of Wetland Area and Function? Sustainability 13 (11), 5951.

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It is increasingly common for developers to be asked to manage the impacts of their projects on biodiversity by restoring other degraded habitats that are ecologically equivalent to those that are impacted. These measures, called biodiversity offsets, generally aim to achieve ‘no net loss’ (NNL) of biodiversity. Using spatially-explicit modeling, different options were compared in terms of their performance in offsetting the impacts on wetlands of the planned urban expansion around Grenoble (France). Two implementation models for offsetting were tested: (a) the widespread bespoke permittee-led restoration project model, resulting in a patchwork of restored wetlands, and (b) recently-established aggregated and anticipated “banking” approaches whereby larger sets of adjacent parcels offset the impacts of several projects. Two ecological equivalence methods for sizing offsets were simulated: (a) the historically-prevalent area-based approach and (b) recently introduced approaches whereby offsets are sized to ensure NNL of wetland functions. Simulations showed that a mix of functional methods with minimum area requirements was more likely to achieve NNL of wetland area and function across the study area and within each subwatershed. Our methodology can be used to test the carrying capacity of a landscape to support urban expansion and its associated offsetting in order to formulate more sustainable development plans.

Diagne C., Leroy B., Vaissière A.C., Gozlan R.E., Roiz D., Jarić Y., Salles J.-M., Bradshaw C.J.A., Courchamp F. (2021) High and rising economic costs of biological invasions worldwide. Nature 592 (7855), 571-576.

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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.

Diallo M., Ollier S., Mayeur A., Fernandez-Manjarres J., García-Fernández A., Iriondo J.M., Vaissière A.C., Colas B. (2021) Plant translocations in Europe and the Mediterranean: geographic and climatic directions and distances from source to host sites. Journal of Ecology

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Although the number of plant translocations has been rapidly increasing for two decades, no study is available to date that examines the directions and distances of plant displacements, which is essential (though not sufficient) information for considering translocations as a management tool to enable species to cope with the consequences of climate change. In this paper we study the geographic and climatic directions and distances from source to host sites in 638 source-and-host site pairs of plant translocations that aimed to achieve viable populations in the last decades in the Western Palearctic (Europe and the Mediterranean). Translocation distances ranged from 0 to 661 km, but were generally short, most (82%) being less than 25 km, due to both ecological considerations and legal and administrative constraints. The host sites were not preferentially located in any geographic direction or in any altitude relative to the source sites. In contrast, on a climate compass constructed from a principal component analysis of seven bioclimatic variables, the host sites were slightly, but significantly, under colder climatic conditions than the source sites. This observation appears to be more the consequence of an effort to counteract already felt effects of climate change than to anticipate future changes. The climatic distance between source sites and actual host sites was generally smaller than between source sites and randomly selected host sites at a given distance or within a given geographical area, which may be the result of a desire to minimise climatic differences or differences in other ecological factors correlated with climatic differences. Synthesis. This study is the first to compare, geographically and climatically, the source sites of biological material and the host sites in translocations of wild plant species to obtain viable populations. Past translocations are in line with mitigating the consequences of global warming onplant species, because the host sites were in slightly cooler conditions than the source sites. Despite this, climate considerations seem to have been little taken into account in plant translocation projects and will certainly have to be much more so in a future with rapid anthropogenic climate change.

Vaissière A.C., Meinard Y. (2021). A policy framework to accommodate both the analytical and normative aspects of biodiversity in ecological compensation. Biological Conservation 253, 108897.

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Ecological compensation is a principle according to which negative impacts on biodiversity should be compensated for. Biodiversity offsetting (BO) is the requirement to compensate quantified losses by quantified biodiversity gains considered to be equivalent. Compensation policies reducing ecological compensation to BO overlook the fact that the notion of biodiversity has both analytical and normative aspects. To substantiate this idea, we analyze the French case, which is one of the most developed ecological compensation policies in the world. We show that this policy is torn between two antagonistic trends. The first trend leads decision-makers and practitioners to embark on a numerical quest for “no net loss” of biodiversity. The second trend explores new organizational strategies consisting of a change in spatiotemporal scale and scope. This second trend challenges the precepts of BO and the associated objective of no net loss. We argue that the first trend reflects the analytical aspect of biodiversity but ignores the normative one, while the second trend does the exact opposite. A serious ecological compensation policy should reconcile both aspects to do justice to the complexity of biodiversity. We elaborate the organizational building blocks of such a two-tier ecological compensation policy, which is key to participate in stopping the erosion of biodiversity.


Diagne C., Leroy B., Gozlan R.E., Vaissière A.C., Assailly C., Nuninger L., Roiz D., Jourdain F., Jarić I., Courchamp F. (2020). INVACOST: a public database of the economic costs of biological invasions worldwide. Scientific Data 7, 277.

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Biological invasions are responsible for tremendous impacts globally, including huge economic losses and management expenditures. Efficiently mitigating this major driver of global change requires the improvement of public awareness and policy regarding its substantial impacts on our socio-ecosystems. One option to contribute to this overall objective is to inform people on the economic costs linked to these impacts; however, until now, a reliable synthesis of invasion costs has never been produced at a global scale. Here, we introduce InvaCost as the most up-to-date, comprehensive, harmonised and robust compilation and description of economic cost estimates associated with biological invasions worldwide. We have developed a systematic, standardised methodology to collect information from peer-reviewed articles and grey literature, while ensuring data validity and method repeatability for further transparent inputs. Our manuscript presents the methodology and tools used to build and populate this living and publicly available database. InvaCost provides an essential basis (2419 cost estimates currently compiled) for worldwide research, management efforts and, ultimately, for data-driven and evidence-based policymaking.

Vaissière A.C., Quétier F., Calvet C., Levrel H., Wunder S. (2020). Biodiversity offsets and payments for environmental services: clarifying the family ties. Ecological Economics 169, 106428.

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Biodiversity Offsets (BO) and Payments for Environmental Services (PES) are sometimes used interchangeably to characterize innovative economic tools to conserve or restore biodiversity, ecosystems, or their services. We assume that a confusion between PES and BOcan have negative implications for biodiversity conservation. In this paper, we argue that these two tools follow different targets and have different founding principles, and thus, their basic mode of functioning would only coincide under special circumstances and institutional contexts. Here, we propose a new definition of BO, delimiting them more clearly from PES, and use practical examples to underscore conceptual differences. Both tools require specific policy framework conditions, in terms of rights, responsibilities, and enforcement. If unmet, however, the implications for biodiversity conservation outcomes are stronger for BO than for PES since BO are explicitly linked to biodiversity losses, while PES typically are not. PES experiences can certainly inform BO implementationvis-à-vis contract design and enforcement, but these PES lessons need to be enacted vis-à-vis BO specific requirements, in order not to underestimate generic risks in their implementation: if a PES scheme fails, payments can be stopped; if a BO fails, biodiversity losses remain.

Vaissière A.C., Quétier F., Calvet C., Latune J. (2020). Quelles implications possibles du monde agricole dans la compensation écologique ? Vers des approches territoriales. Sciences, Sciences, Eaux et Territoires 31 Eviter, réduire, compenser : et si on l’organisait à l’échelle des territoires ? 38–43.

English title: What involvement of the agriculture sector in ecological compensation? Toward territorial approaches

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Getting farmers and other rural stakeholders actively engaged in biodiversity offsetting requires to assess the compatibility of biodiversity offset goals with the management practices that farmers are actually willing to carry out on their land. We describe the impediments to enrolling farmers as offset providers and assess innovations available to overcome them. Lastly, we offer perspectives on using offset financing to foster a sectorial and landscape-level ‘agro-ecological’ transition of farming systems.

Bas A., Imbert I., Clermont S., Reinert M.-E., Berté C., Calvet C, Vaissière A.C. (2020). Approches anticipées et planifiées de la compensation écologique en Allemagne : vers un retour d’expérience pour la France ? Sciences, Eaux et Territoires 31 Eviter, réduire, compenser : et si on l’organisait à l’échelle des territoires ? 44–49.

English title: Anticipated and planned approaches of ecological compensation in Germany: toward a feedback for France?

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The mitigation hierarchy was introduced in 1976 in the first French and German laws on nature protection. While planned and pooled compensation organizations appeared in Germany at the end of the 1990s, it was not until the beginning of 2010 in France that we observed a shift towards a more pooled (mitigation banks institutionalized in 2016 in the Biodiversity Act) and planned (recent emergence of anticipated land strategies at the regional or local level) compensation organization. However, the type of biodiversity and the implementation modalities targeted by the different modes of compensation organization differ between the two countries. In this article, we put into perspective the German and French ecological compensation systems.


Roussel S., Tardieu L., Vaissière A.C. (2019). Compensation Écologique et Agriculture : Est-Ce Compatible ? La Revue Economique, 70, 123-137.

English title: Biodiversity offsetting and agriculture: is this compatible?

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Biodiversity Offsets (BO) are activities that provide measurable ecological gains that are equivalent to the ecological losses induced by development projects. In France, BO have been very poorly implemented since their introduction in the 1976 Nature Protection Act. The new Law on Biodiversity voted in August 2016 specifies the implementation framework of BO and introduces more coercive rules. Provided that almost 60% of the French territory is dedicated to agricultural activities, farmers may be particularly asked to be BO operators. In this paper, we investigate through a choice experiment if farmers are ready to become BO operators and under which conditions they would enrol in BO contracts. Besides, we analyse how the agricultural sector specificities may involve preference heterogeneity for BO contracts. We show that the BO contracts requirements will not lead to a systematic involvement of farmers. This allows us to suggest direction for BO contracts to be proposed by planners, with regards to farmers’ profiles according to the types of impacts they have to offset.


Scemama P., Kermagoret C., Levrel H., Vaissière A.C. (2018). L’économie néo-institutionnelle comme cadre de recherche pour questionner l’efficacité de la compensation écologique, in Dossier : La fabrique de la compensation écologique : controverses et pratiques. Natures Sciences Sociétés, 26 (2), 150–158. 

English title: New institutional economics as a research framework to investigate the efficiency of ecological offsets

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Any analysis of the effectiveness of a public policy implies adopting a normative approach, i.e. defining “what should be” and then discussing the best way to achieve it. In the context of ecological compensation, this objective is defined as the achievement of equivalence between the losses related to a project and the gains linked to the compensatory measures. This equivalence is based on a substitution logic, which is the core concern of environmental economics. In this paper, we start by presenting the contributions of this theoretical field to the study of compensation effectiveness. We also highlight its limitations. This led us to give preference to the framework of the new institutional economics which studies the effectiveness of the compensation as a problem of organization of the actors, taking into account their institutional and environmental background. Moreover, we show that the hypotheses underlying the reasoning of environmental economics set the debate in the sphere of weak sustainability while its political reading is more closely related to the sphere of strong sustainability for which the new institutional economics offer original and relevant contributions.

Vaissière A.C., Tardieu L., Quétier F., Roussel S. (2018). Preferences for Biodiversity Offset Contracts on Arable Land: A Choice Experiment Study with Farmers. European Review of Agricultural Economics, 45 (4), 553–582.

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Biodiversity Offsetting (BO) is aimed at achieving no net loss of biodiversity in the context of economic development. Through a choice experiment in northern France, we show that farmers have a clear preference for not signing up BO contracts. The contracts they accept may only be suitable for offsetting temporary impacts on already degraded areas of natural habitat but not for permanent impacts on high quality habitat. By increasing the enroled acreage in a BO per farmer, the introduction of a conditional monetary bonus can improve the organisational and ecological efficiency of BO, although with an increased cost for developers.


Vaissière A.C., Levrel H., Pioch S. (2017). Wetland mitigation banking: Negotiations with stakeholders in a zone of ecological-economic viability. Land Use Policy 69, 512-518.

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Wetland mitigation banking (WMB) is an organizational form that attempts to balance the ecological goals of wetland conservation and the economic goals of development with the aim of improving the implementation of wetland offsetting. Given the resulting tension, it is important to understand how the way stakeholders employ the WMB regulatory framework affects the goal of No Net Loss of wetlands. In this study, we interviewed WMB stakeholders in Florida in the United States to identify their strategies during negotiations around different aspects of defining wetland mitigation credits (e.g. service areas, types of credit and credit release schedules). Using the approach of New Institutional Economics, we found that within a framework of well-defined rules that nonetheless allow flexibility, WMB enables a field of action for negotiating within a zone of ecological-economic viability – in part due to the stakeholders’ interest in maintaining a good reputation in this field. Outside of this zone of viability a wetland mitigation bank proposal collapses for economic or ecological reasons.

Vaissière A.C., Levrel H., Scemama P. (2017). Biodiversity offsetting: clearing up misunderstandings between conservation and economics to take further action. Biological Conservation 206: 258–262.

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Biodiversity offsetting (BO) is increasingly adopted as a conservation tool by many countries while it has received several critics among which its possible links to several forms of Nature economicization. We believe that some of these concerns rest on misunderstandings generated by the difficulty to interpret economic principles from ecological viewpoints and the lack of a common language between conservationists and economists. Because this issue is vivid and the concepts not yet stabilized, key aspects of the potential advances and limits of BO to conservation practice must be clarified. This short communication (1) addresses the links between the BO concept and the central sustainability principle and (2) clarifies key assumptions regarding three potential Nature economicization roles recurrently attributed to BO. We show that the BO principle reflects a move from welfare equivalency mostly inherited from mainstream economic approach based on weak sustainability criteria toward an ecological economic approach based on strong sustainability criteria and the quest for ecological equivalence. However, the way the countries implement BO influences the possibility to reach strong sustainability. Although we show that BO could be linked to a certain acceptance of “commodification”, we suggest that BO can neither be considered as a “marketization” and nor generally as a “privatization” of Nature. We therefore argue that these conceptual misunderstandings should not hamper conservation objectives and that BO must be framed within interdisciplinary approaches combining ecology, economy and socio-political aspects. We conclude that conservation science has a major role to play in defining the boundaries of BO.

Levrel H., Scemama P., Vaissière A.C. (2017). Should we be wary of mitigation banking? Evidence regarding the risks associated with this wetland offset arrangement in Florida. Ecological Economics 135: 136–149. 

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This paper describes and analyzes the risks associated with using mitigation banking for the conservation of wetlands in Florida in the United States. First, we attempt to identify and summarize the main ecological and socio-economic risks regarding mitigation banking that have been discussed in previous studies. Then we analyze the institutional responses adopted by US regulators to limit these risks. We have used empirical evidence including interviews and data analysis to assess the effectiveness of these responses. Our main findings are that the recent regulatory responses adopted to face risks associated with mitigation banking seem to be more effective than what is often assumed. These responses are underpinned by the emergence of a hybrid mode of governance that combines market characteristics and regulatory constraints, and which contributes to enforcing wetland compensation in Florida. However, we also observed some risks inherent in this system, in particular the redistribution of ecosystem services, as the distance between impact sites and compensation sites seems to have increased in Florida in the last several years. In addition, the question is still pending regarding whether or not No Net Loss of wetlands is really achieved through mitigation banking.

Pioch S., Johnston M. W., Vaissière A.C., Berger F., Jacob C., Dodge R. (2017). An update of the Visual_HEA software to improve the implementation of the Habitat Equivalency Analysis method. Ecological Engineering 105, 276-283. 

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The Visual_HEA software tool was created in 2006 to facilitate the assessment of losses and gains in ecosystem services related to compensatory mitigation under the United States National Resource Damage Assessment Act (NRDA). Habitat Equivalency Analysis (HEA) is an ecological equivalence assessment method under NRDA that can be performed using the Visual_HEA software and for which it was named. The newers version – 2.6 – was recently enhanced and tested over several years to be adapted to the European context and to facilitate adherence to the Environmental Liability Directive (2004/35/EC) to compensate for environmental damages. Herein, enhancements, limitations, and a turnkey method of calculating variable gain and loss rates over space and time using the 2.6 version of the software are discussed. Major functionality enhancements include a quarterly discount calculation, increased decimal precision, gain calculations that extend into perpetuity, and the elimination of many small software “bugs”. A case study about the accidental pollution of the Mimizan River from a sodium hypochlorite spill at a paper mill illustrates the new functionalities of the software. The use of the HEA method to assess ecosystem services related to biodiversity offset has been widespread thanks to the development of this user-friendly software package. Furthermore, the HEA method implemented in Visual HEA_2.6 is recommended by the European Commission to enforce its Environmental Liability Directive and to size mitigations after accidental environmental damages.


Vaissière A.C., Bierry A., Quétier F. (2016). Mieux compenser les impacts sur les zones humides : modélisation de différentes approches dans la région de Grenoble. Sciences Eaux & Territoires 21, 14–19. PDF

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Limiter autant que possible les impacts sur les milieux humides est une obligation pour tout projet d’aménagement devant faire l’objet d’une autorisation. En cas d’impacts résiduels négatifs significatifs, des mesures compensatoires permettant de rétablir la qualité environnementale de la zone impactée à un niveau au moins équivalent à son état initial doivent être menées sur d’autres zones dégradées. À travers l’exemple de la région de Grenoble, en pleine expansion urbaine, cet article propose d’analyser plusieurs méthodes innovantes de mise en œuvre de politiques de compensation écologique en utilisant une approche plus intégrée et adaptée aux besoins du territoire.

Jacob C., Vaissière A.C., Bas A., Calvet C. (2016). Investigating the inclusion of ecosystem services in biodiversity offsetting. Ecosystem Services 21, 92–102. 

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In response to growing international interest regarding the consideration of ecosystem services (ES) in the framework of biodiversity offsetting (BO) and the current lack of guidelines on the subject, we investigated the potential inclusion of ES in BO, highlighting the risks and opportunities. Our argument is premised on the assumption that a practical link already exists between the two and that most of the tools required to make this approach operational are available. But so far, ES are not explicitly taken into account when calculating and designing offsets (whether regulatory or voluntary). One way to integrate ES in BO is to use the Environmental Impact Assessments’ framework, here we propose a logical way to integrate ES at each step of the implementation of the mitigation hierarchy and provide details on the links with existing practice. In our proposal, the inclusion of ES is presented as a way to complement current approaches based on the assessment of habitats/species/ecological functions rather than to replace them. We argue that measures proposed to offset biodiversity losses, in addition to respecting ecological performance standards, should equally be chosen to minimize residual losses of ES. The latter require offsetting by different types of complementary measures. Implementing these recommendations as good practice should strengthen the weight of biodiversity, demonstrate consideration of social equity, and result in better acceptance of development projects and the measures proposed to offset them.


Vaissière A.C., Levrel H. (2015). Biodiversity offset markets: what are they really? An empirical approach to wetlands mitigation banking. Ecological Economics 110, 81–88. PDF

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In the United States, the most recent regulatory tool for carrying out biodiversity offsets for wetlands is the mitigation banking system. This system aims to compensate for many small impacts on wetlands by carrying out restoration projects on fewer but larger wetland areas in order to reach the goal of no net loss of biodiversity. Mitigation banking has been criticized based on its categorization as an environmental “market”. This paper discusses the real nature of biodiversity offset markets, using three complementary approaches: a conventional economic approach, an empirical sociological approach, and a new institutional economics theory approach. To accomplish this, we carried out a field research study in Florida. The results show that the mitigation banking system is a hybrid organizational form halfway between a market and a hierarchy. Compared to permittee responsible mitigation, it has interesting specific features resulting from political tradeoffs, which seem adapted to implement public policy dealing with the complex and poorly predictable issue of biodiversity. Thus, it may be a useful organizational innovation to implement ecological compensation more efficiently, provided it is properly regulated.


Vaissière A.C., Levrel H., Pioch S., Carlier A. (2014). Biodiversity offsets for offshore wind farm projects: the current situation in Europe. Marine Policy 48, 172–183. PDF

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The European Union׳s energy policy aims to increase the proportion of energy derived from renewable sources in Europe. Marine renewable energy, offshore wind energy especially, contributes to the renewable energy mix. Offshore wind farms appear to be clean, and are supported by governments and NGOs as a way to reduce the use of conventional energy resources and thus decrease greenhouse gas emissions. However, developing infrastructure in marine areas can impact marine ecosystems. European directives ask offshore wind farm developers to carry out an Environmental Impact Assessment (EIA) including a mitigation hierarchy, i.e. envisaging measures that would avoid, reduce, and if possible offset significant adverse effects on ecosystems and human activities. This paper reviews EIA reports from seven European countries and is focused on impacts on the open water marine environment. According to the reports, measures have been taken for avoiding and reducing impacts, so there should be no significant negative residual impacts and hence no need of offsets. But the mitigation hierarchy for ecological impacts seems to have been incompletely implemented, because it is unlikely that there are no significant residual impacts. The paper proposes some technical and ecological explanations, followed by some governance and social explanations, for the absence of biodiversity offsets.


Vaissière A.C., Levrel H., Hily C., Le Guyader D. (2013). Selecting ecological indicators to compare maintenance costs related to the compensation of damaged ecosystem services. Ecological Indicators 29, 255–269. PDF

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The aim of this paper is to compare different maintenance costs of ecosystem service arising from a hypothetical case of environmental damage in order to help to understand how the different ecosystem services are considered in decision making processes. Compensatory measures are aimed precisely at maintaining the level of supply of ecosystem services. According to the literature, compensatory measures like restoration are usually applied to specific ecosystem services. We used the Millennium Ecosystem Assessment (MEA) categories of ecosystem service. For each MEA category, several ecological indicators are selected, and the cost of the compensatory measures required to fulfill the goal of no net loss is assessed using the Habitat Equivalency Analysis (HEA). The results of this analysis highlight differences between compensatory measures and their associated costs depending on the category of ecosystem services targeted. Maintenance costs are high for regulating services, low for provisioning services, and more difficult to determine for cultural services (high or low depending on the indicator selected). We discuss the implications of this result, noting that it is more rational for project developers to focus their attention on provisioning services if the legal regulation of compensation is lax or if indicators relative to cultural and regulating services are not precise enough.