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.