Biodiversity offsets and the challenge of achieving no net loss

Sentiment and attitudes toward offsetting and the biodiversity market in online media articles

Biodiversity offsetting, a conservation approach to offset loss of habitat and ecosystem services, has been widely accepted and implemented in different legislative frameworks around the globe. I assigned sentiment scores (from -3 [very negative] to +3 [very positive]) to online news articles to examine public sentiment toward offsetting. I identified 86 pertinent articles published from 2013 to 2023 by web scraping online media outlets through keywords. I examined article content based on topics commonly associated in scientific literature with offsetting, such as risks or financial aspects. Most articles were from Australia (44%), 16% were from the United Kingdom, and 5% were from Colombia and Madagascar. Three distinct groups covered finances (n = 47), species, and social impacts of offsetting (n = 23) and offsetting frameworks (n = 16). Articles covering monetary and finance aspects had a lower predicted sentiment score (-0.72, 95% CI -0.98 to -0.47) than articles that covered new, alternative offsetting forms (-0.15, 95% CI -0.46 to 0.17), such as mitigation banking and credits. In articles focused on charismatic species and loss of livelihood, offsetting risk and social issues were associated with low sentiment scores (<-0.85). Sentiment scores were high for articles on offsetting at a multicountry or global scale (0.47, 95% CI -0.06 to 0.99), and scores were the lowest in Australia (-1.03, 95% CI -1.36 to -0.70). Public sentiment based on media articles was generally negative toward offsetting, and many of the ecological and methodological issues and risks were reflected in the articles, but mitigation measures as a prerequisite to offsetting were mentioned in only 18% of all articles. With the seemingly high public interest in conservation and hence offsetting, it will be imperative to expand the current breadth of information about offsetting that is being communicated or made available to the public.

Achieving biodiversity net gain by addressing governance gaps underpinning ecological compensation policies

Biodiversity compensation policies have emerged around the world to address the ecological harms of infrastructure expansion, but historically compliance is weak. The Westminster government is introducing a requirement that new infrastructure developments in England demonstrate they achieve a biodiversity net gain (BNG). We sought to determine the magnitude of the effects of governance gaps and regulator capacity constraints on the policy's potential biodiversity impacts. We collated BNG information from all new major developments across six early-adopter councils from 2020 to 2022. We quantified the proportion of the biodiversity outcomes promised under BNG at risk of noncompliance, explored the variation in strategies used to meet developers' biodiversity liabilities, and quantified the occurrence of simple errors in the biodiversity metric calculations. For large developments and energy infrastructure, biodiversity liabilities frequently met within the projects' development footprint. For small developments, the purchase of offsets was most common. We estimated that 27% of all biodiversity units fell into governance gaps that exposed them to a high risk of noncompliance because they were associated with better-condition habitats delivered on-site that were unlikely to be monitored or enforced. More robust governance mechanisms (e.g., practical mechanisms for monitoring and enforcement) would help ensure the delivery of this biodiversity on-site. Alternatively, more biodiversity gains could be delivered through off-site biodiversity offsetting. For the latter case, we estimated that the demand for offsets could rise by a factor of 4; this would substantially increase the financial contributions from developers for conservation activities on private land. Twenty-one percent of development applications contained a simple recurring error in their BNG calculations. One-half of these applications were approved by councils, which may indicate under-resourcing in council development assessments. Our findings demonstrate that resourcing and governance shortfalls risk undermining the policy's effectiveness.

Translocation of deadwood in ecological compensation: A novel way to compensate for habitat loss

Restoration of degraded habitat is frequently used in ecological compensation. However, ecological restoration suffers from innate problems of long delivery times of features shown to be good proxies for biodiversity, e.g., large dead trees. We tested a possible way to circumvent this problem; the translocation of hard-to-come deadwood substrates from an impact area to a compensation area. Following translocation, deadwood density in the compensation area was locally equivalent to the impact area, around 20 m3 ha-1, a threshold for supporting high biodiversity of rare and red-listed species. However, deadwood composition differed between the impact and compensation area, showing a need to include more deadwood types, e.g., late decomposition deadwood, in the translocation scheme. To guide future compensation efforts, the cost for translocation at different spatial scales was calculated. We conclude that translocation of deadwood could provide a cost-efficient new tool for ecological compensation/restoration but that the method needs refinement.

Mitigation bank applications for freshwater systems: Control mechanisms, project complexity, and caveats

Biodiversity and mitigation banking has become a popular alternative offsetting mechanism, especially for freshwater species and systems. Central to this increase in popularity is the need for sound control mechanisms to ensure offset functionality. Two commonly used mechanisms are monitoring requirements and staggered release of bank credits over time. We used data from 47 banks in the United States, targeting freshwater systems and species. Based on the 47 banks meeting our criteria we showed that control mechanisms generally scale with increased project complexity and that banks release most of their total credit amount within the first 3 years. We further showed that advance credits are common and can increase the potential for credit release without providing tangible ecological benefits. Physical and biological assessment criteria commonly used by banks let us identify three main bank types focusing on connectivity, physical aspects, and habitat and species and their application possibilities and caveats to provide different ecosystem benefits for freshwater species and systems affected by anthropogenic development.

Assessment of the sustainability and producibility of adobe constructions reinforced with Ca-based binders: Environmental life cycle analysis (LCA) and 3D printability

This study investigated the usability of adobe samples reinforced with calcium-based binders in a 3D-printed technique. These adobe samples' physical, mechanical, durability and microstructure characteristics were investigated and their 3D printability characteristics experimentally. In the case of adobe production by 3D-printing method, the compressive strength decreased by 9-33 % compared to mold casting. While the thermal conductivity coefficient of adobe samples varied between 0.833 and 1.421 W/mK, the thermal conductivity was reduced by 43 % thanks to the preference for gypsum. Within the scope of the LCA analysis, the slightest effect in terms of environmental damage was observed in mixtures containing gypsum compared to cement and slaked lime mixtures. As a result, it was determined that adobe's physical and mechanical characteristics could be improved by using gypsum, lime and cement, and these mixtures can be used in 3D-printing. It was determined that more sustainable adobe production is possible with gypsum and lime.

Offsetting environmental impacts beyond climate change: the Circular Ecosystem Compensation approach

Since the Paris Agreement entered into force, climate neutrality and associated compensation schemes are even more on the agenda of politics and companies. Challenges of existing offsetting schemes include the rather theoretical saving scenario and the limited scope of considered impacts. To address some of these limitations, this paper proposes the Circular Ecosystem Compensation (CEC) approach based on monetization of LCA results and Ecosystem Valuation. CEC consists of six steps: i) carrying out a life cycle assessment, ii) reducing the environmental impacts, iii) determining environmental costs applying monetization methods, iv) deriving the environmental value based on restoration costs methods, v) implementing the ecological restoration of ecosystems and vi) monitoring of the renaturation measures. Thus, CEC allows to offset a broad set of environmental impacts beyond climate change (e.g., acidification, eutrophication, land use, water use) in a real ecosystem by renaturation of degraded ecosystems. Environmental burdens and environmental benefits are balanced on a monetary basis, as the renaturation measures are monetized and used to compensate the monetized LCA results, e.g., of a product, organization or individual. In a case study, the implementation of the approach is presented to show the practical implementation of the CEC. The challenges of CEC include the integration of further impact categories, the availability of up-to-date and reliable monetization methods, the asynchrony and time-lag of the compensation from an ecosystem and biodiversity perspective and the proof of cost-efficiency of the renaturation measures. It is further discussed, if CEC can be a step beyond "climate neutrality" towards "environmental neutrality". The proposed approach should be further tested and is intended to foster progress in more comprehensive and robust offsetting of environmental impacts beyond climate change.

Guidelines for selecting an appropriate currency in biodiversity offset transactions

When designing biodiversity offset transactions, selecting the appropriate currency for measuring losses and gains to biodiversity is crucial. Poorly designed currencies reduce the likelihood that the proposed offset will sufficiently compensate for the development impact on the affected biota. We present a framework for identifying appropriate offset currencies for terrestrial biodiversity features, either vegetation communities or particular species. The guidelines were developed based on a review of issues and solutions presented in the existing literature, including government policies and guidance. We assert that while benchmark-based condition scores provide a suitable offset transaction currency for vegetation communities, this approach is also commonly applied to individual species based on the often-unproven assumption that vegetation quality is a proxy for the value of a site to that species. We argue that species are better served by species-specific currencies based on either species abundance, or the suitability and amount of the habitat available. For species where it is practical and meaningful to measure the abundance on site, an abundance-based currency using either directly observable or proxy indicators is the most representative measure of the net impact on the species. In other instances, such as when species are difficult to locate, or not reliably present on site, a currency based on the quality and amount of habitat is preferable. The habitat-quality component should be measured relative to its value for the species, with the most important attributes weighted accordingly. Ensuring the currency used in biodiversity offset transactions is practical to measure, and relevant to the species or vegetation community is an important step in minimising the net biodiversity losses from unavoidable impacts.

A Meta-analysis on the Effectiveness of Offsetting Strategies to Address Harm to Freshwater Fishes

Offsetting aims to compensate for negative impacts due to authorized anthropogenic impacts associated with development. While anchored into legislation, residual or chronic impacts can occur after offset establishment. Advice and best practice on how to approach these impacts is rare. To address this, we reviewed 30 projects based on a systematic review and meta-analysis in freshwater ecosystems dealing with residual or long-term negative impacts to provide application advice for: habitat creation, habitat restoration, and biological and chemical manipulation. Project information was obtained through Boolean search terms and web-scraping. Habitat creation projects had a pooled effect size of 0.8 and offsetting ratios of 1:5 with high biomass increases of &gt;140% compared to pre-establishment, associated with them. Habitat restoration projects targeted a wide range of species and communities with a pooled effect size of 0.66, offset ratios ranging from 1:1.2 to 1:4.6, and biomass increases generally &gt; 100% compared to pre-restoration. Biological manipulation had the lowest effect size (0.51) with stocking being highly variable both in terms of biomass benefits and project outcomes pointing towards being mostly applicable in cases of direct fish harm not related to habitat aspects. We conclude that (1) all three assessed approaches have a potential application use for offsetting residual or chronic harm with approach-specific caveats. (2) Implementation costs differ across offset methods, with connectivity and side-channel projects having the lowest biomass gain per area costs (3) Time to first benefits required one to two years with time lags needing to be accounted for in the implementation and monitoring process.

A global overview of biodiversity offsetting governance

We analyze the development of biodiversity offsetting governance through a research-weaving approach. Here, we combine information from a systematized review of the literature and a qualitative analysis of the institutional developments in different world regions. Through this triangulation, we synthesize and map the different developmental streams of biodiversity offsetting governance around the globe over the last four decades. We find that there is a global mainstreaming of core principles such as avoidance, no-net-loss, and a mitigation hierarchy, as well as pooling and trading of offsets for unavoidable residual damages. Furthermore, we can observe an ongoing diversification of institutional designs and actors involved. Together this constitutes an emerging regime complex of biodiversity offsetting governance that comes with both a set of shared norms and a growing institutional complexity. While this may imply institutional innovation through diversification and policy experimentation, it also raises questions regarding the effectiveness of offsetting practices.

China's Mismatch of Public Awareness and Biodiversity Threats under Economic Trade

China is one of the countries with high biodiversity on the globe, but suffers extreme biodiversity loss due to the increasingly interconnected economy. Understanding the nation-level public awareness of biodiversity under economic trades is crucial for implementing sustainable production and consumption of Sustainable Development Goals (SDGs). This study is the first to assess the public awareness of biodiversity loss associated with China's interprovincial trades by utilizing social media data and the multiregion input-output (MRIO) table. Results show that China's interprovincial trades cause heavy threats not only to local species but to distant species. Approximately 60% of provinces displace over half of their consumption-based biodiversity threats to other provinces. Nevertheless, individuals do not clearly realize their responsibility for the distant biodiversity they consumed, with a large mismatch both in popularity (Gini index = 0.51, Robin index = 39.57) and donation (Gini index = 0.69, Robin index = 54.58). To alleviate this phenomenon, our analysis suggests that the expansion of national-level nature reserves may be effectively beneficial to public biodiversity awareness, showing significantly positive partial correlation coefficients with individuals' popularity and donations. These insights provided by this study offer targeted information for conservation and call for synergistic collaboration between the civil society, especially consumers, and governments to turn the tide of biodiversity loss.

'Old wine in a new bottle': conceptualization of biodiversity offsets among environmental practitioners in Uganda

Biodiversity offsets are increasingly adopted to mitigate the negative impacts of development activities on biodiversity. However, in practice, there are inconsistencies in how biodiversity offsets are understood and implemented. Based on interviews with environmental practitioners, the study sought to explore the conceptual understanding of biodiversity offsets among personnel involved in the design and implementation of offset schemes in Uganda. The study employed a 'technical use analysis' to seek personal interpretation and operationalization of the concept of biodiversity offsets. The results revealed that the concept tends to be simplified and adjusted to individual, project, and country contexts. The respondents had varied perceptions of biodiversity offsets in practice as compared to the theoretical concept. Biodiversity offsets were classified under five terms: trade-offs, payments, substitutes, compensations, and mitigation measures. The terms were derived from perceived inability of the measure to attain no net loss, and similarities of biodiversity components and services across impact and offset sites. Biodiversity offsets were thus considered no different from ordinary environmental conservation measures, contributing nothing unique to the conservation agenda. The study concludes that widespread implementation of biodiversity offsets under prevailing perceptions will escalate biodiversity loss. The study recommends emphasis on attaining no net loss through implementing outcome-based offsets as opposed to purpose-based offsets, that require delivering of 'no net loss' gains prior to projects being considered biodiversity offsets.

Assessing Conservation and Mitigation Banking Practices and Associated Gains and Losses in the United States

Conservation and mitigation banks allow their proponents to buy credits to offset the negative residual impacts of their development projects with the goal of no net loss (NNL) in the ecosystem function and habitat area. However, little is known about the extent to which these bank transactions achieve NNL. We synthesized and reviewed 12,756 transactions in the United States which were related to meeting area and ecological equivalence (n = 4331) between the approved negative impact and offset. While most of these transactions provided an offset that was equal to or greater than the impacted area, approximately one quarter of the transactions, especially those targeting wetlands, did not meet ecological equivalence between the impact and offset. This missing ecological equivalence was often due to the significantly increasing use of preservation, enhancement, and rehabilitation over creating new ecosystems through establishment and re-establishment. Stream transactions seldom added new ecosystem area through creation but mainly used rehabilitation in order to add offset benefits, in many cases leading to a net loss of area. Our results suggest that best practice guidance on habitat creation as well as the incentivization of habitat creation must increase in the future to avoid net loss through bank transactions and to meet the ever-accelerating global changes in land use and the increased pressure of climate change.

The Bighorn Habitat Assessment Tool: A Method to Quantify Conservation Value on Landscapes Impacted by Mining

We present a methodology to assess the conservation value of mitigation lands for desert bighorn sheep (Ovis canadensis nelsoni) within landscapes impacted by historic and ongoing industrial uses. The Bighorn Habitat Assessment Tool (BHAT) was developed to support the adaptive management of the Cushenbury population of bighorn sheep located on the north slope of the San Bernardino Mountains in southern California, USA. We use a novel formulation of conservation value integrating the results of resource selection function analysis and reclamation credits, reflecting the degree to which degraded habitat is enhanced to benefit wild sheep. Our method seeks to balance conservation objectives simultaneously with the economic development of a working mine landscape. Specifically, the BHAT can be used to (a) establish a habitat reserve providing maximum benefit to the unique requirements of bighorn sheep; (b) incentivize voluntary action by industry to ensure mining activities are compatible with conservation; (c) allow for the evaluation of multiple mine planning and resource management alternatives; and (d) ensure that future compensatory mitigation actions for mining activity are grounded in the best available science. Our methodology is transferrable to the management of other wild sheep populations occupying mine-influenced landscapes for which sufficient data are available to complete resource selection analyses.

Ecological equivalence assessment: The potential of genetic tools, remote sensing and metapopulation models to better apply the mitigation hierarchy

Within the framework of the mitigation hierarchy, biodiversity offsetting is the main tool promoted to reach No Net Loss. One of the determining factors of offsetting success is the evaluation of ecological equivalence. Various equivalence assessment methods (EAMs) have been developed to provide a framework to evaluate the balance between expected biodiversity losses and gains. In the context of achieving No Net Loss, EAMs must address challenges of Operationality, Currency, Uncertainty, Spatial scale and Time frame. In this study, we investigated the way the most widely used EAMs address these challenges, positing that certain tools from ecological science could limit the trade-offs between these challenges and improve the ecological assessment process. To this end, we analysed the risks and benefits associated with the inclusion of genetic tools (landscape genetics and eDNA), remote sensing and metapopulation models in selected EAMs. Our results revealed trade-offs between these five challenges, in particular between Operationality and Currency. The EAMs varied strongly in these two aspects, depending on the general assessment approach and the biodiversity component they focus on. To a lesser degree, Time frame and Spatial scale also differed between the methods. We identified that the integration of the different tools differs among them, being easier for remote sensing and metapopulation models than for the genetic tools. Nevertheless, the integration resulted in benefits compared to the current use of the methods - benefits that included improving the objectivation of the assessment and the automatization potential. The tools also show potential for automatization, which could have major benefits for operationality. In terms of risks, the integration of these tools increases the technical complexity of the methods, requiring new skills, and would change the overall approach of the ecological assessment.

Mitigation translocation as a management tool

Mitigation translocation is a subgroup of conservation translocation, categorized by a crisis-responsive time frame and the immediate goal of relocating individuals threatened with death. However, the relative successes of conservation translocations with longer time frames and broader metapopulation- and ecosystem-level considerations have been used to justify the continued implementation of mitigation translocations without adequate post hoc monitoring to confirm their effectiveness as a conservation tool. Mitigation translocations now outnumber other conservation translocations, and understanding the effectiveness of mitigation translocations is critical given limited global conservation funding especially if the mitigation translocations undermine biodiversity conservation by failing to save individuals. We assessed the effectiveness of mitigation translocations by conducting a quantitative review of the global literature. A total of 59 mitigation translocations were reviewed for their adherence to the adaptive scientific approach expected of other conservation translocations and for the testing of management options to continue improving techniques for the future. We found that mitigation translocations have not achieved their potential as an effective applied science. Most translocations focused predominantly on population establishment- and persistence-level questions, as is often seen in translocations more broadly, and less on metapopulation and ecosystem outcomes. Questions regarding the long-term impacts to the recipient ecosystem (12% of articles) and the carrying capacity of translocation sites (24% of articles) were addressed least often, despite these factors being more likely to influence ultimate success. Less than half (47%) of studies included comparison of different management techniques to facilitate practitioners selecting the most effective management actions for the future. To align mitigation translocations with the relative success of other conservation translocations, it is critical that future mitigation translocations conform to an established experimental approach to improve their effectiveness. Effective mitigation translocations will require significantly greater investment of time, expertise, and resources in the future.

Quality assessment of mitigation translocation protocols for protected plants in France

Mitigation translocations are increasingly used worldwide in response to land planning pressures. The quality of translocation protocols and their adjustment to the ecological traits of the translocated populations are crucial to optimise translocation success. We studied the quality of translocation protocols presented in derogation requests, a mandatory step in France to translocate a protected plant species. We analysed 103 translocation proposals for 93 different species in 92 files examined between 2018 and 2020. After tracing the history of the place of translocations in legal procedures in France, we assessed each translocation proposal according to an evaluation grid, which involved the quantity and quality of information on plant species and translocation sites in the files and the quality of translocation protocols. We have shown that the translocation protocols are of low quality, with a lot of missing information. The biology and ecology of the species suggested for translocation are not sufficiently known, nor are the ecological characteristics of the host sites. Derogation requests that received a favourable opinion from the assessment body are more likely to propose a protected host site and post-translocation monitoring. We believe that, to optimise their outcome, mitigation translocations need to be improved upstream, with more detailed protocols and better species knowledge. We highly recommend following the same guidelines for mitigation translocations as for conservation translocations.

Precision, Applicability, and Economic Implications: A Comparison of Alternative Biodiversity Offset Indexes

The rates of ecosystem degradation and biodiversity loss are alarming and current conservation efforts are not sufficient to stop them. The need for new tools is urgent. One approach is biodiversity offsetting: a developer causing habitat degradation provides an improvement in biodiversity so that the lost ecological value is compensated for. Accurate and ecologically meaningful measurement of losses and estimation of gains are essential in reaching the no net loss goal or any other desired outcome of biodiversity offsetting. The chosen calculation method strongly influences biodiversity outcomes. We compare a multiplicative method, which is based on a habitat condition index developed for measuring the state of ecosystems in Finland to two alternative approaches for building a calculation method: an additive function and a simpler matrix tool. We examine the different logic of each method by comparing the resulting trade ratios and examine the costs of offsetting for developers, which allows us to compare the cost-effectiveness of different types of offsets. The results show that the outcomes of the calculation methods differ in many aspects. The matrix approach is not able to consider small changes in the ecological state. The additive method gives always higher biodiversity values compared to the multiplicative method. The multiplicative method tends to require larger trade ratios than the additive method when trade ratios are larger than one. Using scoring intervals instead of using continuous components may increase the difference between the methods. In addition, the calculation methods have differences in dealing with the issue of substitutability.

Mitigating the Impacts of Development Corridors on Biodiversity: A Global Review

Development corridors are extensive, often transnational and linear, geographical areas targeted for investment to help achieve sustainable development. They often comprise the creation of hard infrastructure (i.e., physical structures) and soft infrastructure (i.e., policies, plans, and programmes) involving a variety of actors. They are globally widespread, and likely to be a significant driver of habitat loss. Here, we describe the development corridors phenomenon from a biodiversity perspective and identify the elements of best practice in biodiversity impact mitigation. We use these to carry out a review of the peer reviewed literature on corridors to respond to three questions: (i) how impacts on biodiversity and ecosystem services are assessed; (ii) what mitigation measures are discussed to manage these impacts; and (iii) to what extent do these measures approximate to best practice. We found that of 271 publications on development corridors across all continents (except for Antarctica) mentioning biodiversity or ecosystem services, only 100 (37%) assessed impacts on biodiversity and 7 (3%) on ecosystem services. Importantly, only half of these (52, 19% of the total 271 articles) discussed mitigation measures to manage these impacts. These measures focused on avoidance and minimisation and there was scant mention of restoration or ecological compensation illustrating a deficient application of the mitigation hierarchy. We conclude that the academic literature on corridors does not give sufficient consideration to comprehensive mitigation of biodiversity impacts. To change this, impact assessment research needs to acknowledge the complexity of such multi-project and multi-stakeholder initiatives, quantify biodiversity losses due to the full suite of their potential direct, indirect and cumulative impacts, and follow all the steps of the mitigation hierarchy impact framework. We suggest a series of research avenues and policy recommendations to improve impact assessments of corridors towards achieving better biodiversity outcomes.

Metrics and Equivalence in Conservation Banking

Offsets are increasingly used to compensate for unavoidable development impacts on species and habitats. Many offset programs pursue no net loss, but research on the success of these programs is lacking, including research on conservation banking’s success in conserving protected species under the US Endangered Species Act. This article provides a case study analysis of two conservation banks in the state of California, comparing the conservation gains provided by banks with the losses from development impacts. It provides an analysis of credits and metrics to determine whether the gains are equal to the losses in terms of type, condition, and amount. Results do show that the gains exceed the losses in terms of acreage. However, the program uses indirect metrics (acreage), and the equivalence of the losses and gains, besides habitat type and size, is not reflected. Banks provide a baseline in their documentation and conduct monitoring of species abundance and habitat quality, but they do not use it to measure additional conservation gains. More detailed metrics and transparent indices to certify the acres in production could allow for a quantification of conservation benefits and an evaluation of program success. However, selecting standardized metrics is challenging because they need to be species-specific to reflect the goal of species recovery, and still be operational in practice.

When is an Offset Not an Offset? A Framework of Necessary Conditions for Biodiversity Offsets

Biodiversity offsets have become a widely accepted means of attempting to compensate for biodiversity loss from development, and are applied in planning and decision-making processes at many levels. Yet their use is contentious, and numerous problems with both the concept and the practice have been identified in the literature. Our starting point is the understanding that offsets are a kind of biodiversity compensation measure through which the goal of no net loss (or net gain) of biodiversity can be at least theoretically achieved. Based on a typology of compensation measures distinguishing between habitat protection, improvement (including restoration, habitat creation and improved management practices) and other compensation, we review the literature to develop a framework of conditions that must be met if habitat protection and improvement initiatives can be truly considered offsets and not merely a lesser form of compensation. It is important that such conceptual clarity is reflected in offset policy and guidance, if offsets are to be appropriately applied and to have any chance of fully compensating for biodiversity loss. Our framework can be used to support the review and ongoing development of biodiversity offset policy and guidance, with the aim of improving clarity, rigour and therefore the chances that good biodiversity outcomes can be achieved.

Three ways to deliver a net positive impact with biodiversity offsets

Biodiversity offsetting is the practice of using conservation actions, such as habitat restoration, management, or protection, to compensate for ecological losses caused by development activity, including construction projects. The typical goal of offsetting is no net loss (NNL), which means that all ecological losses are compensated for by commensurate offset gains. We focused on a conceptual and methodological exploration of net positive impact (NPI), an ambitious goal that implies commitment beyond NNL and that has recently received increasing attention from big business and environmental nongovernmental organizations. We identified 3 main ways NPI could be delivered: use of an additional NPI multiplier; use of slowly developing permanent offsets to deliver additional gains after NNL has first been reached during a shorter offset evaluation time interval; and the combination of permanent offsets with partially temporary losses. An important and novel variant of the last mechanism is the use of an alternate mitigation hierarchy so that gains from the traditional third step of the mitigation hierarchy (i.e., onsite rehabilitation) are no longer be counted toward reduced offset requirements. The outcome from these 3 factors is that for the same ecological damage, larger offsets will be required than previously, thereby improving offset success. As a corollary, we show that offsets are NNL only at 1 ephemeral point in time, before which they are net negative and after which they become either NPI or net negative impact, depending on whether permanent offsets are combined with partially temporary losses or if temporary offset gains are combined with partially permanent losses. To achieve NPI, offsets must be made permanent, and they must achieve NNL during an agreed-upon offset evaluation period. An additional NPI-multiplier and use of the modified mitigation hierarchy will deliver additional NPI gains. Achieving NPI is fully conditional on prior achievement of NNL, and NNL offsets have been frequently observed to fail due to inadequate policy requirements, poor planning, or incomplete implementation. Nevertheless, achieving NPI becomes straightforward if NNL can be credibly reached first.

Achieving biodiversity net gain in a neoliberal economy: The case of England

The United Kingdom Government intends to require land development in England to contribute to improving biodiversity values. The basis for this, the offsetting of impacts on biodiversity, stems from and reinforces a neoliberal economic approach, fits with the privatising of conservation, and at a landscape level may improve biodiversity values. However, challenging decision-makers is the current lack of robust evidence that offsetting works, meaning allowing development despite uncertain future biodiversity benefits. Additionally, financial support for local government is declining, making it unclear whether and how effective independent auditing of biodiversity net gain will be.

Moving towards integrating soil into spatial planning: No net loss of soil-based ecosystem services

Degradation of ecosystems and the related loss of ecosystem services have called for new policies to achieve no net loss (NNL) of or even net gain between detrimental environmental impacts and restoration or preservation measures. While biodiversity offsetting has a long tradition, soils have rarely been considered in the accounting. Considering the crucial role of soil for ecosystem functioning and biodiversity and the increasing pressure on soil resources, we investigate how a NNL strategy building on a soil-based ecosystem services index can help steer sustainable spatial development. An ecosystem services' soil quality index allows to explicitly address the interests of a broad range of stakeholder on soil uses. Using a market-driven spatial planning instrument based on a land price fee linked to the soil quality index, we demonstrate how soil quality loss and related ecosystem services could be reduced by up to 60% compared to current practice in a case study in Switzerland. More importantly, the suggested instrument allows to account for the spatial variability of the supply of the ecosystem services and the diversity of stakeholder demands for various soil qualities. We close with a discussion on the consequences of implementing a soil-based NNL strategy for spatial development and its generic application for steering settlement development.

Local conditions and policy design determine whether ecological compensation can achieve No Net Loss goals

Many nations use ecological compensation policies to address negative impacts of development projects and achieve No Net Loss (NNL) of biodiversity and ecosystem services. Yet, failures are widely reported. We use spatial simulation models to quantify potential net impacts of alternative compensation policies on biodiversity (indicated by native vegetation) and two ecosystem services (carbon storage, sediment retention) across four case studies (in Australia, Brazil, Indonesia, Mozambique). No policy achieves NNL of biodiversity in any case study. Two factors limit their potential success: the land available for compensation (existing vegetation to protect or cleared land to restore), and expected counterfactual biodiversity losses (unregulated vegetation clearing). Compensation also fails to slow regional biodiversity declines because policies regulate only a subset of sectors, and expanding policy scope requires more land than is available for compensation activities. Avoidance of impacts remains essential in achieving NNL goals, particularly once opportunities for compensation are exhausted.

Countries are adopting ecological compensation policies aimed at achieving no net loss of biodiversity and ecosystem services. Here, Sonter and colleagues apply spatial simulation models to case studies in Australia, Brazil, Indonesia, and Mozambique to show that compensation alone is not sufficient to preserve biodiversity.

Environmental mitigation hierarchy and biodiversity offsets revisited through habitat connectivity modelling

Biodiversity loss is accelerating because of unceasing human activity and land clearing for development projects (urbanisation, transport infrastructure, mining and quarrying …). Environmental policy-makers and managers in different countries worldwide have proposed the mitigation hierarchy to ensure the goal of "no net loss (NNL) of biodiversity" and have included this principle in environmental impact assessment processes. However, spatial configuration is hardly ever taken into account in the mitigation hierarchy even though it would greatly benefit from recent developments in habitat connectivity modelling incorporating landscape graphs. Meanwhile, national, European and international commitments have been made to maintain and restore the connectivity of natural habitats to face habitat loss and fragmentation. Our objective is to revisit the mitigation hierarchy and to suggest a methodological framework for evaluating the environmental impact of development projects, which includes a landscape connectivity perspective. We advocate the use of the landscape connectivity metric equivalent connectivity (EC), which is based on the original concept of "amount of reachable habitat". We also refine the three main levels of the mitigation hierarchy (impact avoidance, reduction and offset) by integrating a landscape connectivity aspect. We applied this landscape connectivity framework to a simple, virtual habitat network composed of 14 patches of varying sizes. The mitigation hierarchy was addressed through graph theory and EC and several scenarios of impact avoidance, reduction and compensation were tested. We present the benefits of a habitat connectivity framework for the mitigation hierarchy, provide practical recommendations to implement this framework and show its use in real case studies that had previously been restricted to one or two steps of the mitigation hierarchy. We insist on the benefits of a habitat connectivity framework for the mitigation hierarchy and for ecological equivalence assessment. In particular, we demonstrate why it is risky to use a standard offset ratio (the ratio between the amount of area negatively impacted and the compensation area) without performing a connectivity analysis that includes the landscape surrounding the zone impacted by the project. We also discuss the limitations of the framework and suggest potential improvements. Lastly, we raise concerns about the need to rethink the strategy for biodiversity protection. Given that wild areas and semi-natural habitats are becoming scarcer, in particular in industrialised countries, we are convinced that the real challenge is to quickly reconsider the current vision of "developing first, then assessing the ecological damage", and instead urgently adopt an upstream protection strategy that would identify and protect the land that must not be lost if we wish to maintain viable species populations and ecological corridors allowing them the mobility necessary to their survival.

Trends in biodiversity and habitat quantification tools used for market-based conservation in the United States

Market-based conservation mechanisms are designed to facilitate the mitigation of harm to and conservation of habitats and biodiversity. Their potential is partly hindered, however, by the quantification tools used to assess habitat quality and functionality. Of specific concern are the lack of transparency and standardization in tool development and gaps in tool availability. To address these issues, we collected information via internet and literature searchers and through conversations with tool developers and users on tools used in U.S. conservation mechanisms, such as payments for ecosystem services (PES) and ecolabel programs, conservation banking, and habitat exchanges. We summarized information about tools and explored trends among and within mechanisms based on criteria detailing geographic, ecological, and technical features of tools. We identified 69 tools that assessed at least 34 species and 39 habitat types. Where tools reported pricing, 98% were freely available. More tools were applied to states along the U.S. West Coast than elsewhere, and the level of tool transferability varied markedly among mechanisms. Tools most often incorporated conditions at numerous spatial scales, frequently addressed multiple risks to site viability, and required 1-83 data inputs. Most tools required a moderate or greater level of user skill. Average tool-complexity estimates were similar among all mechanisms except PES programs. Our results illustrate the diversity among tools in their ecological features, data needs, and geographic application, supporting concerns about a lack of standardization. However, consistency among tools in user skill requirements, incorporation of multiple spatial scales, and complexity highlight important commonalities that could serve as a starting point for establishing more standardized tool development and feature-incorporation processes. Greater standardization in tool design may expand market participation and facilitate a needed assessment of the effectiveness of market-based conservation.

Scale dependency of conservation outcomes in a forest-offsetting scheme

Offset schemes help avoid or revert habitat loss through protection of existing habitat (avoided deforestation), through the restoration of degraded areas (natural regrowth), or both. The spatial scale of an offset scheme may influence which of these 2 outcomes is favored and is an important aspect of the scheme's design. However, how spatial scale influences the trade-offs between the preservation of existing habitat and restoration of degraded areas is poorly understood. We used the largest forest offset scheme in the world, which is part of the Brazilian Forest Code, to explore how implementation at different spatial scales may affect the outcome in terms of the area of avoided deforestation and area of regrowth. We employed a numerical simulation of trade between buyers (i.e., those who need to offset past deforestation) and sellers (i.e., landowners with exceeding native vegetation) in the Brazilian Amazon to estimate potential avoided deforestation and regrowth at different spatial scales of implementation. Allowing offsets over large spatial scales led to an area of avoided deforestation 12 times greater than regrowth, whereas restricting offsets to small spatial scales led to an area of regrowth twice as large as avoided deforestation. The greatest total area (avoided deforestation and regrowth combined) was conserved when the spatial scale of the scheme was small, especially in locations that were highly deforested. To maximize conservation gains from avoided deforestation and regrowth, the design of the Brazilian forest-offset scheme should focus on restricting the spatial scale in which offsets occur. Such a strategy could help ensure conservation benefits are localized and promote the recovery of degraded areas in the most threatened forest landscapes.

Towards Unpacking the Theory Behind, and a Pragmatic Approach to Biodiversity Offsets

The use of biodiversity offsets to compensate for residual impacts on biodiversity resulting from a development or land-use change, is becoming more prevalent. While much has been published on this topic, there has been little published on the theoretical foundation on which biodiversity offsets are based. This paper seeks to unpack the theoretical and practical tenets of biodiversity offsets in relation to the public trust doctrine, responsibilities of the developer and the State, and significant unmitigable impacts on biodiversity. It was reasoned that the responsibility of the developer and the life of a biodiversity offset are finite, and that the concept of 'in perpetuity' may not exist practically and in law. It was further discovered that a sound understanding of the public trust doctrine is critical for consistent offset-based decision-making, particularly in those circumstances where an impasse between the potential significant loss to biodiversity and an indispensable need for a development or land-use change arises.

Biodiversity Offset Program Design and Implementation

Biodiversity offsets are applied in many countries to compensate for impacts on the environment, but research on regulatory frameworks and implementation enabling effective offsets is lacking. This paper reviews research on biodiversity offsets, providing a framework for the analysis of program design (no net loss goal, uncertainty and ratios, equivalence and accounting, site selection, landscape-scale mitigation planning, timing) and implementation (compliance, adherence to the mitigation hierarchy, leakage and trade-offs, oversight, transparency and monitoring). Some more challenging aspects concern the proper metrics and accounting allowing for program evaluation, as well as the consideration of trade-offs when regulations focus only on the biodiversity aspect of ecosystems. Results can be used to assess offsets anywhere and support the creation of programs that balance development and conservation.

Expert predictions of changes in vegetation condition reveal perceived risks in biodiversity offsetting

Biodiversity offsetting typically involves the trade of certain losses of habitat with uncertain future conservation benefits. Predicting the latter requires estimates of two outcomes; the biodiversity losses without conservation management (averted loss), and the biodiversity gains with conservation management (management gain). However, because empirical data to inform these estimates are limited, they are normally guided by expert opinion, often derived via unstructured methods without consideration of uncertainty. Here we used a structured elicitation with 29 experts to gather estimates of averted loss and management gain at offset sites. We used two methods; (i) experts estimated change in an aggregate biodiversity value (vegetation condition) and; (ii) experts provided probabilistic estimates of change for individual vegetation condition attributes, such as the richness and cover of plant growth forms. On average, experts predicted there would be only modest improvements with conservation management, yet uncertainty and variation among experts was large; in some cases, conservation benefits were not predicted. Estimates of change in vegetation condition suggested that benefits were from both averted loss and management gains and were thought to most likely arise in cases where starting condition was low to moderate. Similar patterns were observed for individual vegetation condition attributes, with management gains, relative to a reference, tending to be negatively correlated with starting value. Our study finds that: (i) on average, gains at offset sites are expected to be small, (ii) at many sites, experts do not believe gains can be obtained, and (iii) experts' opinions can be divergent resulting in elevated levels of uncertainty. The potential for losses under conservation management highlights the need to: identify those components of biodiversity most likely to benefit from conservation management; better understand those situations when offset obligations are most likely to be met and conversely those situations with higher risk; and further develop offset mechanisms that encourage early or prior gains. These findings together with the global proliferation of biodiversity offsetting, provide a strong imperative to improve empirical data and investment in long-term, site-based monitoring of biodiversity outcomes at offset sites.

Water quality improvements offset the climatic debt for stream macroinvertebrates over twenty years

Many species are accumulating climatic debt as they fail to keep pace with increasing global temperatures. In theory, concomitant decreases in other stressors (e.g. pollution, fragmentation) could offset some warming effects, paying climatic debt with accrued environmental credit. This process may be occurring in many western European rivers. We fit a Markov chain model to ~20,000 macroinvertebrate samples from England and Wales, and demonstrate that despite large temperature increases 1991-2011, macroinvertebrate communities remained close to their predicted equilibrium with environmental conditions. Using a novel analysis of multiple stressors, an accumulated climatic debt of 0.64 (±0.13 standard error) °C of warming was paid by a water-quality credit equivalent to 0.89 (±0.04)°C of cooling. Although there is finite scope for mitigating additional climate warming in this way, water quality improvements appear to have offset recent temperature increases, and the concept of environmental credit may be a useful tool for communicating climate offsetting.

No net loss for people and biodiversity

Governments, businesses, and lenders worldwide are adopting an objective of no net loss (NNL) of biodiversity that is often partly achieved through biodiversity offsetting within a hierarchy of mitigation actions. Offsets aim to balance residual losses of biodiversity caused by development in one location with commensurate gains at another. Although ecological challenges to achieve NNL are debated, the associated gains and losses for local stakeholders have received less attention. International best practice calls for offsets to make people no worse off than before implementation of the project, but there is a lack of clarity concerning how to achieve this with regard to people's use and nonuse values for biodiversity, especially given the inevitable trade-offs when compensating biodiversity losses with gains elsewhere. This is particularly challenging for countries where poor people depend on natural resources. Badly planned offsets can exacerbate poverty, and development and offset impacts can vary across spatial-temporal scales and by location, gender, and livelihood. We conceptualize the no-worse-off principle in the context of NNL of biodiversity, by exploring for whom and how the principle can be achieved. Changes in the spatial and temporal distribution of biodiversity-related social impacts of a development and its associated offset can lead to social inequity and negatively impact people's well-being. The level of aggregation (regional, village, interest group, household, and individual) at which these social impacts are measured and balanced can again exacerbate inequity in a system. We propose that a determination that people are no worse off, and preferably better off, after a development and biodiversity offset project than they were before the project should be based on the perceptions of project-affected people (assessed at an appropriate level of aggregation); that their well-being associated with biodiversity losses and gains should be at least as good as it was before the project; and that this level of well-being should be maintained throughout the project life cycle. Employing this principle could help ensure people are no worse off as a result of interventions to achieve biodiversity NNL.

The Simplification of Biological Diversity in International and EU Law

Every system that manages or assesses biodiversity rests on a simplification of its complexity. The simplification of biodiversity is debatable and difficult; even, for example, regarding the elements on which the assessment and management should focus. Nevertheless, within law, there are assessment and management schemes that are based on a simplified understanding of the meaning of [the construct of] ‘biodiversity’. For example, the Ecosystem Approach, European Union (EU) Habitats Directive, and the EU Water Framework Directive try to assess the status of different biodiversity elements based on their different ‘biodiversity’ simplifications. As the conservation of biodiversity is a vital global question, it is important to include the right elements within the ‘biodiversity’ construct to achieve no net loss. Based on international and EU law, I conceptualize a consistent legal simplification of ‘biodiversity’.

Accounting for no net loss: A critical assessment of biodiversity offsetting metrics and methods

Biodiversity offset strategies are based on the explicit calculation of both losses and gains necessary to establish ecological equivalence between impact and offset areas. Given the importance of quantifying biodiversity values, various accounting methods and metrics are continuously being developed and tested for this purpose. Considering the wide array of alternatives, selecting an appropriate one for a specific project can be not only challenging, but also crucial; accounting methods can strongly influence the biodiversity outcomes of an offsetting strategy, and if not well-suited to the context and values being offset, a no net loss outcome might not be delivered. To date there has been no systematic review or comparative classification of the available biodiversity accounting alternatives that aim at facilitating metric selection, and no tools that guide decision-makers throughout such a complex process. We fill this gap by developing a set of analyses to support (i) identifying the spectrum of available alternatives, (ii) understanding the characteristics of each and, ultimately (iii) making the most sensible and sound decision about which one to implement. The metric menu, scoring matrix, and decision tree developed can be used by biodiversity offsetting practitioners to help select an existing metric, and thus achieve successful outcomes that advance the goal of no net loss of biodiversity.

A Global Mitigation Hierarchy for Nature Conservation

Efforts to conserve biodiversity comprise a patchwork of international goals, national-level plans, and local interventions that, overall, are failing. We discuss the potential utility of applying the mitigation hierarchy, widely used during economic development activities, to all negative human impacts on biodiversity. Evaluating all biodiversity losses and gains through the mitigation hierarchy could help prioritize consideration of conservation goals and drive the empirical evaluation of conservation investments through the explicit consideration of counterfactual trends and ecosystem dynamics across scales. We explore the challenges in using this framework to achieve global conservation goals, including operationalization and monitoring and compliance, and we discuss solutions and research priorities. The mitigation hierarchy's conceptual power and ability to clarify thinking could provide the step change needed to integrate the multiple elements of conservation goals and interventions in order to achieve successful biodiversity outcomes.

Outcomes from 10 years of biodiversity offsetting

We quantified net changes to the area and quality of native vegetation after the introduction of biodiversity offsetting in New South Wales, Australia-a policy intended to "prevent broad-scale clearing of native vegetation unless it improves or maintains environmental values." Over 10 years, a total of 21,928 ha of native vegetation was approved for clearing under this policy and 83,459 ha was established as biodiversity offsets. We estimated that no net loss in the area of native vegetation under this policy will not occur for 146 years. This is because 82% of the total area offset was obtained by averting losses to existing native vegetation and the rate that these averted losses accrue was over-estimated in the policy. There were predicted net gains in 10 of the 14 attributes used to assess the quality of habitat. An overall net gain in the quality of habitat was assessed under this policy by substituting habitat attributes that are difficult to restore (e.g. mature trees) with habitat attributes for which restoration is relatively easy (e.g. tree seedlings). Long-term rates of annual deforestation did not significantly change across the study area after biodiversity offsetting was introduced. Overall, the policy examined here provides no net loss of biodiversity: (i) many generations into the future, which is not consistent with intergenerational equity; and (ii) by substituting different habitat attributes, so gains are not equivalent to losses. We recommend a number of changes to biodiversity offsetting policy to overcome these issues.

How economic contexts shape calculations of yield in biodiversity offsetting

We examined and analyzed methods used to create numerical equivalence between sites affected by development and proposed conservation offset sites. Application of biodiversity offsetting metrics in development impact and mitigation assessments is thought to standardize biodiversity conservation outcomes, sometimes termed yield by those conducting these calculations. The youth of biodiversity offsetting in application, however, means little is known about how biodiversity valuations and offset contracts between development and offset sites are agreed on in practice or about long-term conservation outcomes. We examined how sites were made commensurable and how biodiversity gains or yields were calculated and negotiated for a specific offset contract in a government-led pilot study of biodiversity offsets in England. Over 24 months, we conducted participant observations of various stages in the negotiation of offset contracts through repeated visits to 3 (anonymized) biodiversity offset contract sites. We conducted 50 semistructured interviews of stakeholders in regional and local government, the private sector, and civil society. We used a qualitative data analysis software program (DEDOOSE) to textually analyze interview transcriptions. We also compared successive iterations of biodiversity-offsetting calculation spreadsheets and planning documents. A particular focus was the different iterations of a specific biodiversity impact assessment in which the biodiversity offsetting metric developed by the U.K.'s Department for Environment, Food and Rural Affairs was used. We highlight 3 main findings. First, biodiversity offsetting metrics were amended in creative ways as users adapted inputs to metric calculations to balance and negotiate conflicting requirements. Second, the practice of making different habitats equivalent to each other through the application of biodiversity offsetting metrics resulted in commensuration outcomes that may not provide projected conservation gains. Third, the pressure of creating value for money diminished projected conservation yields.