A disaggregated biodiversity offset accounting model to improve estimation of ecological equivalency and no net loss

Abstract

35Biodiversity offsetting is a mechanism aimed at achieving biodiversity gains to 36 compensate for the residual impacts of development activities on biodiversity. 37Estimating the ecological equivalence of biodiversity lost to development with that 38 gained by the offset requires a currency that captures the biota of interest and an 39 accounting model to evaluate the exchange. Ecologically robust, and user-friendly 40 decision support tools improve the transparency of biodiversity offsetting and assist in 41 the decision making process. Here we describe a tool developed for the New Zealand 42 Department of Conservation that offers a mechanism to transparently design and 43 evaluate biodiversity offsets intended to deliver no net loss. It is a relatively 44 disaggregated accounting model that balances like-for-like biodiversity trades using a 45 suite of area by condition currencies to calculate net present biodiversity value 46 (NPBV) to account individually for each measured biodiversity element of interest. 47The NPBV is used to evaluate whether a no net loss exchange is likely for each 48 biodiversity attribute. More disaggregated currencies have an advantage over 49 aggregated currencies (which use composite metrics) in that they account for each 50 itemised biodiversity element of concern. The disaggregated model we present can be 51 used to account for a variety of biodiversity types in an offset exchange, and for 52 different scales and complexities of development and impacts within both statutory 53 and voluntary frameworks. 54 55 Keywords biodiversity offsetting; disaggregated currencies; net present biodiversity 56 value 57 58 3

The many meanings of no net loss in environmental policy

“…Given the risks associated with over-or under-estimating future scenarios 13,15 , some authors have argued that using a reference scenario fixed at an explicit, known state such as 'now' or 'before the impact' carries less risk, and has the added advantage of simplicity 22 . Indeed, most non-specialists including public stakeholders probably presume this meaning of NNL (that is, no further loss of biodiversity compared to what now exists, whatever the cause of losses).…”

Modeling biodiversity benchmarks in variable environments

“…We estimated benchmarks for each of six growth forms: ferns, forbs, grasses, shrubs, trees, and others. Growth forms are an intermediate grouping that simplify the complexity of full species inventories without reducing these inventories to simple biodiversity metrics such as total species richness and total abundance or cover (Mayfield et al 2010, Maseyk et al 2016, Yen . We observed substantial variation in species richness and cover benchmarks among growth forms, which supports the use of disaggregated benchmarks in our study system.…”

Biodiversity Offset Program Design and Implementation

“…What is being accounted for at biodiversity banks is referred to as 'credit metrics' and affects the aim of conservation efforts and functioning of the regulatory market [9,60]. Options are vast; indicators can be practice or performance based and focus on area, functionality, species or habitat [60][61][62][63][64]. Moreno-Mateos et al (2015) discuss ecological, non-instrumental (intrinsic, cultural) and instrumental (ES) values of biodiversity that should be accounted for to avoid ecological as well as ethical losses [39].…”