This is a guest post by Lucie Bezombes, doc­toral stu­dent at EDF and IRSTEA (France). This com­ment is the expres­sion of the author’s thoughts and expe­ri­ences and as such is acknowl­edged as a fruit­ful con­tri­bu­tion to the dis­cus­sion on bio­di­ver­sity off­sets. If you want to react or clar­ify your own posi­tion (under­pin or dis­prove Lucie’s rea­son­ing), please leave a reply below!

An essen­tial issue for bio­di­ver­sity off­set to achieve “no net loss” is to demon­strate eco­log­i­cal equiv­a­lence between losses caused by impacts and gains due to off­set. Meth­ods of equiv­a­lence eval­u­a­tion have been devel­oped world­wide to esti­mate bio­di­ver­sity losses and gains so as to assess eco­log­i­cal equiv­a­lence and size off­set mea­sures. They have been devel­oped in a country-specific envi­ron­men­tal social-cultural pol­icy and eco­log­i­cal con­texts and are sub­se­quently adapted only in these con­texts. In France, no method has yet been imposed or sug­gested in leg­is­la­tion, which lead to het­ero­ge­neous off­set practices.

• Thus, the aim of my PhD is to develop a method to eval­u­ate eco­log­i­cal equiv­a­lence adapted to French con­text, tak­ing into account all key equiv­a­lence con­sid­er­a­tions: eco­log­i­cal (what bio­di­ver­sity is to assess? What indi­ca­tors best rep­re­sent this biodiversity?);
• spa­tial (how both impacted and off­set sites are inte­grated in sur­round­ing land­scape?); tem­po­ral (how to take into account interim losses due to time lag in ecosys­tems maturation?);
• and uncer­tain­ties (what con­sid­er­a­tion of pre­vi­ous off­set feed­backs to best size off­set accord­ing to off­set risks of failure?).

The method will be devel­oped to be oper­a­tional (the skill level required to imple­ment the method is rea­son­ably con­sis­tent with the cur­rent skill level of the envi­ron­men­tal con­sul­tancy and pub­lic author­ity involved in envi­ron­men­tal impact stud­ies in the coun­try, and that the method can be imple­mented in a small amount of time and at a rea­son­able cost), exhaus­tive (it takes account of all four above-mentioned key equiv­a­lence con­sid­er­a­tions, and that a max­i­mum amount of nec­es­sary infor­ma­tion is taken into account) and with sci­en­tific basis, to ensure objec­tive assess­ment based on eco­log­i­cal the­o­ries and input from pre­vi­ous studies).

My PhD is financed by the French gov­ern­ment “CIFRE” grant for PhD stu­dents and the Elec­tric­ité de France (EDF) Research and Devel­op­ment Depart­ment. I also do my PhD in part­ner­ship with IRSTEA Greno­ble (where I work most of the time) and the French National Museum of Nat­ural History.