Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Abstract

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects' compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.wetland Cumplimiento y Función Ambiental de las Compensaciones por Biodiversidad en las Aguas Dulces de América del Norte y Europa Resumen: El cambio del uso de suelo causado por el desarrollo humano es un causante fundamental de la pérdida de biodiversidad. Para reducir estos impactos se gastan miles de millones de dólares en las compensaciones por biodiversidad. Sin embargo, todavía son raros los estudios de evaluación de la efectividad de los proyectos de compensación que examinen componentes como el cumplimiento general y la función de los proyectos. Revisamos 577 proyectos de compensación en ecosistemas de agua dulce que incluyeran las medidas del tamaño del proyecto, el tipo de ecosistema acuático (p. ej.: arroyo, humedal), la medida de compensación (p. ej.: mejoramiento, restauración, creación) y una evaluación del cumplimiento y eléxito funcional del proyecto. La información sobre los proyectos se obtuvo de bases de datos científicas y del gobierno y de la literatura gris. A pesar de la inversión considerable que existe para los proyectos de compensación persistieron problemas cruciales. Aunque el cumplimiento y la función estuvieron relacionados entre sí, un nivel alto de cumplimiento no garantizó un * email jonathan.ruppert@trca.on.ca Article impact statement: Despite legislation in places like the United States, EU, Australia, and Canada, biodiversity offsets do not show high levels of ecosystem function.Freshwater Offsets nivel alto de función. Sin embargo, los proyectos grandes en relación con elárea tuvieron una mejor función que los proyectos pequeños. La función incrementó cuando los proyectos se enfocaban en la productividad o en características específicas del ecos...

The ecological outcomes of biodiversity offsets under “no net loss” policies: A global review

“…Imperfect compliance rates per se do not guarantee failure of NNL policies from an ecological perspective, as the effects of compliance failure might be outweighed by offset multipliers (Bull, Lloyd, & Strange, ). However, a recent global review including gray literature demonstrated that compliance with offset permit criteria often considerably exceeds the ecological functional performance of those offsets, indicating that achieving compliance is often insufficient to achieve NNL (Theis et al., ). Additionally, low compliance rates do indicate that regulatory enforcement of offset outcomes is often lacking, potentially demonstrating limited institutional interest in the true outcomes of offsetting, thus weakening the probability of NNL outcomes (Walker et al., ).…”

“…Such pecuniary enforcement measures have been demonstrated in the context of other environmental policies to have direct and indirect benefits, such as both increasing compliance rates within punished firms, and inducing spillovers improving compliance within unpunished firms (Gray & Shimshack, ). While improving compliance is likely key, if NNL policies fail to use an appropriate reference system (either the pre‐impact site or control site) to define the compliance criteria for offsets, then even achieving full compliance may well fail to achieve NNL of biodiversity across the paired impacted and offset sites (Theis et al., ).…”

“…Papers were included in our database if they reported observed (i.e., not simulated) ex‐post ecological or land cover‐related outcomes of polices with an explicit NNL‐or‐better objective for aspects of biodiversity. We limited our search to peer‐reviewed publications only (including conference proceedings and book chapters) to attempt to overcome the data quality issues highlighted by other reviews of offset studies that include the gray literature (Theis et al., ), but recognize that the majority of NNL implementation occurs outside academic evaluation. Papers reporting evaluations of individual offset projects were included if they specified the impacts (as a minimum defining the impacted habitat and area) associated with the offsets, thus allowing for a rudimentary assessment of biodiversity losses and gains.…”

Three ways to deliver a net positive impact with biodiversity offsets

“…Step 2 is minimization of impacts, for example, via planning or technical solutions. Project impacts seem to be reduced to the level of compliance with environmental regulation (Theis et al 2020), but it is questionable whether businesses are willing to invest substantial extra money into reducing impacts even further. Putting these initial misgivings aside, our main argument here is about the third level of the mitigation hierarchy, local rehabilitation.…”

The Role of “No Net Loss” Policies in Conserving Biodiversity Threatened by the Global Infrastructure Boom

“…Lastly, even if conservation interventions are implemented in line with offset obligations, incomplete understanding of restoration ecology or the effectiveness of the implemented offset actions can lead to a failure to achieve NNL in biodiversity or ecosystem function. 32,34,87 The Future of No Net Loss Over the last decade, there has been fierce debate about the merits of NNL and biodiversity offsetting and the degree to which it can help achieve or potentially unintentionally undermine conservation outcomes. 37,88,89 Empirical explorations of unintended outcomes remain scarce and largely inconclusive so far (e.g., no evidence for ''license to trash'' in Levrel et al 51 or Gibbons et al 54 ); nevertheless, there is clearly in some contexts merit to the idea that NNL and offsetting policies have been designed by policymakers and influenced by the private sector to ''sell'' the narrative that infrastructural expansion and environmental protection can go hand in hand 75,90 without deep reflection on the considerable barriers to achieving true NNL in practice or the place-based nature of biodiversity and cultural value.…”