Invasive species: solutions to the economic burden

To date, there are 544 species list­ed as inva­sive in France. Among them, the Asian hor­net dec­i­mates domes­tic bees, the tiger mos­qui­to spreads dengue fever and chikun­gun­ya, the prim­rose wil­low caus­es the dis­ap­pear­ance of aquat­ic plants that are close to it… This phe­nom­e­non is called ‘bio­log­i­cal inva­sion’ and these species have cer­tain char­ac­ter­is­tics in com­mon. First, they have been dis­placed by humans, often as unex­pect­ed pas­sen­gers in the trans­port of goods and peo­ple. Once intro­duced, they have sur­vived in their new envi­ron­ment, spread, and had var­i­ous impacts, such as elim­i­na­tion of local species, spread of dis­eases, alter­ation of ecosys­tems or dev­as­ta­tion of crops. 

Inva­sive species are not only a threat to bio­di­ver­si­ty, but also a major eco­nom­ic bur­den. We have recent­ly demon­strat­ed this by sum­maris­ing all exist­ing glob­al eco­nom­ic costs due to inva­sions since 1970, which total $1,288bn¹. This is only a tiny frac­tion of the actu­al costs, as it is only what has been esti­mat­ed and pub­lished. As such, the major­i­ty of the costs have not as yet been assessed. This fig­ure has been grow­ing steadi­ly, tripling every ten years until it reached an esti­mat­ed $163 bil­lion in 2017 alone. A new study just pub­lished in France specif­i­cal­ly shows that inva­sions cost between 1.1 and 10.2 bil­lion euros between 1993 and 2018².

These costs are asso­ci­at­ed with many socio-eco­nom­ic sec­tors (agri­cul­ture, health, tourism, real estate…), and thus affect a vari­ety of pri­vate and pub­lic actors. The bur­den of bio­log­i­cal inva­sions there­fore appears to be sys­temic and requires a strong and con­cert­ed pol­i­cy rather than one-off efforts. Below, we present three ways of tack­ling this burden.

The eco­nom­ic costs gen­er­at­ed by inva­sive species can be divid­ed into dam­age costs (loss of agri­cul­tur­al yields, tourism rev­enues, etc.) and man­age­ment costs (con­trol or erad­i­ca­tion of inva­sive pop­u­la­tions, etc.). All stud­ies show that invest­ment in pre­ven­tive mea­sures is the most cost-effec­tive and effi­cient strat­e­gy against bio­log­i­cal inva­sions. For exam­ple, ear­ly detec­tion and rapid erad­i­ca­tion of new inva­sions is much less cost­ly and has a much high­er suc­cess rate than late action, which often amounts to dam­age control.

It is there­fore essen­tial to strength­en ear­ly detec­tion and mon­i­tor­ing pro­grammes for alien species, so that an effec­tive response can be ini­ti­at­ed at the first sign of neg­a­tive impacts. The vari­ety of these impacts cou­pled with the com­plex­i­ty of imple­ment­ing research rec­om­men­da­tions requires inter­dis­ci­pli­nary and inter­sec­toral approach­es – still too rare – involv­ing ecol­o­gists, econ­o­mists, ana­lysts, soci­ol­o­gists and stake­hold­ers (e.g. bio­di­ver­si­ty managers). 

To raise aware­ness of bio­log­i­cal inva­sions among the gen­er­al pub­lic and pri­vate and pub­lic stake­hold­ers. It is cru­cial to raise aware­ness of pub­lic and pri­vate stake­hold­ers who are respon­si­ble for the translo­ca­tion of liv­ing organ­isms on an international/regional scale (e.g. activ­i­ties linked to trade or live­stock farm­ing) and/or who are vic­tims of their effects (e.g. farm­ers). It is also essen­tial to raise aware­ness among the gen­er­al pub­lic through var­i­ous media and edu­ca­tion­al chan­nels (e.g. in school cur­ric­u­la). Empow­er­ing con­sumers by pro­vid­ing infor­ma­tion on the ori­gin and risks of the organ­isms they buy, for exam­ple in the orna­men­tal trade [i.e. trade in exot­ic ani­mals or plants], would be an excel­lent way to reduce the risks of uncon­trolled intro­duc­tions into the wild.

In this con­text, build­ing bridges between sci­ence and soci­ety is there­fore the key ele­ment. These bridges include (i) the for­mal­i­sa­tion of inter­sec­toral net­works ded­i­cat­ed to research and man­age­ment of bio­log­i­cal inva­sions, (ii) the organ­i­sa­tion of dis­cus­sion work­shops and spe­cif­ic and con­tin­u­ous train­ing, and (iii) the devel­op­ment of par­tic­i­pa­to­ry sci­ence pro­grammes, which rep­re­sent a major asset due to their triple edu­ca­tion­al, sci­en­tif­ic and man­age­ment role. For exam­ple, there is now an appli­ca­tion devel­oped by Europe (Inva­sive Alien Species Europe³) that allows any cit­i­zen to send pho­tos of new pre­sumed species with a view to deploy­ing rapid respons­es in terms of man­age­ment. Despite its inter­est, this appli­ca­tion is not wide­ly publicised. 

There is also great poten­tial in par­tic­i­pa­to­ry sci­ence tools based on arti­fi­cial intel­li­gence to iden­ti­fy species, such as the Pl@ntNet appli­ca­tion, which is a great tool for the ear­ly detec­tion of inva­sions⁴, but is large­ly under-exploit­ed at present. We there­fore empha­sise the need for deci­sion-mak­ers to be involved to achieve con­cert­ed and effi­cient man­age­ment of these bio­log­i­cal invasions. 

Despite the increase in nation­al and inter­na­tion­al laws to com­bat bio­log­i­cal inva­sions, the mag­ni­tude of their dam­age con­tin­ues to accel­er­ate, which sug­gests that these laws remain insuf­fi­cient. There is a need to strength­en species black­lists by rapid­ly updat­ing them once impacts are proven, and to con­sid­er a shift in the legal par­a­digm towards whitelists, i.e. the delib­er­ate intro­duc­tion of new alien species must be autho­rised in advance on the basis of an inva­sion risk assess­ment. Those respon­si­ble for delib­er­ate intro­duc­tions should be held crim­i­nal­ly liable as a deterrent. 

Biose­cu­ri­ty, which con­sists of the inter­cep­tion of alien species pri­or to their intro­duc­tion, is the most effec­tive and cost-effi­cient tool to com­bat the impacts of bio­log­i­cal inva­sions. For exam­ple, some coun­tries severe­ly affect­ed by bio­log­i­cal inva­sions, such as New Zealand and Aus­tralia, have put in place high­ly effec­tive biose­cu­ri­ty pro­to­cols for both tourism and inter­na­tion­al trade. These mea­sures require sub­stan­tial staffing, par­tic­u­lar­ly for the imple­men­ta­tion of sur­veil­lance, quar­an­tine and dis­in­fec­tion pro­to­cols; but they offer insur­ance and a very sig­nif­i­cant net ben­e­fit com­pared to the exces­sive­ly high costs of dam­age and man­age­ment of invasions. 

In France, this legal frame­work and biose­cu­ri­ty mea­sures still appear to be lack­ing, as sug­gest­ed by the recent his­to­ry of inva­sions in France such as the Asian hor­net⁵, the tiger mos­qui­to⁶, the mug­wort⁷, gar­den flat­worms⁸, or the Xylel­la fas­tidiosa bac­teri­um⁹. As island sys­tems are even more frag­ile to inva­sions than con­ti­nen­tal ones, rein­forced biose­cu­ri­ty mea­sures should be imple­ment­ed, par­tic­u­lar­ly in the French over­seas ter­ri­to­ries, includ­ing trav­el between over­seas territories.

Bio­log­i­cal inva­sions cause enor­mous eco­nom­ic loss­es for soci­ety. This loss of earn­ings that we have esti­mat­ed is only the hid­den face of an ice­berg whose total amount is cur­rent­ly unquan­tifi­able, giv­en the diver­si­ty and scale of the impacts of inva­sions – and we are only talk­ing about the mon­e­tary cost here, ignor­ing the irrepara­ble eco­log­i­cal and health costs. Nev­er­the­less, we do have the keys to fight this bur­den since the prob­lem does not lie with the dis­placed species, but rather with our activ­i­ties that cause these dis­place­ments, over which we do have control.