New paper on bio­di­ver­sity off­sets in Bio­log­i­cal Conservation

A new paper has been pub­lished by J. W. Bull, E. J. Milner-Gulland, K. B. Sut­tle and N. J. Singh in Bio­log­i­cal Con­ser­va­tion (Vol­ume 178, Octo­ber 2014, Pages 2–10): “Com­par­ing bio­di­ver­sity off­set cal­cu­la­tion meth­ods with a case study in Uzbek­istan”.

The paper is Open Access funded by Nat­ural Envi­ron­ment Research Coun­cil and can be accessed here: http://www.sciencedirect.com/science/article/pii/S0006320714002663

Abstract

Bio­di­ver­sity off­sets are inter­ven­tions that com­pen­sate for eco­log­i­cal losses caused by eco­nomic devel­op­ment, seek­ing ‘no net loss’ (NNL) of bio­di­ver­sity over­all. Cal­cu­lat­ing the eco­log­i­cal gains required to achieve NNL is non-trivial, with var­i­ous method­olo­gies avail­able. To date, there has been no com­par­i­son among method­olo­gies for a com­mon case study. We use data on indus­trial impacts in Uzbek­istan to pro­vide such a comparison.

We quan­tify losses from 40 years of gas extrac­tion, using empir­i­cal data on veg­e­ta­tion impacts along­side esti­mates of dis­rup­tion to mam­mals. In doing so, we imple­ment a novel tech­nique by esti­mat­ing spa­tial ‘func­tional forms’ of dis­tur­bance to cal­cu­late bio­di­ver­sity impacts. We then use a range of off­set method­olo­gies to cal­cu­late the gains required to achieve NNL. This allows a crude com­par­i­son of the poten­tial bio­di­ver­sity out­comes of “in kind” off­sets (here, veg­e­ta­tion restora­tion) with “out of kind” off­sets (pro­tect­ing fauna from poaching).

We demon­strate that dif­fer­ent meth­ods for cal­cu­lat­ing the required off­set activ­i­ties result in diver­gent out­comes for bio­di­ver­sity (expressed in habi­tat con­di­tion x area, or ‘weighted area’), and dif­fer­ent tra­jec­to­ries in bio­di­ver­sity out­comes over time. An Aus­tralian method is cur­rently being con­sid­ered for adop­tion in Uzbek­istan, but we show that it would require care­ful adjust­ments to achieve NNL there.

These find­ings high­light that the method used to quan­tify losses and gains strongly influ­ences the bio­di­ver­sity out­comes of off­set­ting, imply­ing that off­sets gen­er­ated using dif­fer­ent method­olo­gies are not trans­fer­able between juris­dic­tions. Fur­ther, con­ser­va­tion gains from out of kind off­sets may out­weigh those from strict in kind NNL interpretations.