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Biodiversity: understanding nature to preserve it better

Agroecology: the path to agricultural biodiversity

Denis Couvet, President of the Foundation for Research on Biodiversity and Professor at Muséum National d'Histoire Naturelle
On October 18th, 2022 |
3 min reading time
Denis Couvet
Denis Couvet
President of the Foundation for Research on Biodiversity and Professor at Muséum National d'Histoire Naturelle
Key takeaways
  • Agriculture is the human activity that has the greatest impact on the environment and biodiversity.
  • Agroecology is a model that considers ecological processes and biodiversity, which could alleviate the problems of traditional agriculture.
  • Soil degradation has reduced global land area productivity by 23%.
  • Expecting agriculture to provide energy is cost-effective, but ecologically unsustainable.
  • We need to ensure that public policies work towards relevant agricultural practices, going beyond the CAP.

Why do we want to reduce the impact of agri­cul­ture on the environment?

Because this impact is major. The IPCC con­sid­ers that, at glob­al lev­el, one third of green­house gas emis­sions come from agri­cul­ture. There is also a direct impact on bio­di­ver­si­ty, through the trans­for­ma­tion of habi­tats – this is of course a con­se­quence of defor­esta­tion – the use of fer­tilis­ers and pes­ti­cides, the expan­sion of inva­sive species, and the with­draw­al of bio­mass and water nec­es­sary for ecosys­tems. Agri­cul­ture is the human activ­i­ty that has the great­est impact on bio­di­ver­si­ty, lead­ing to a seri­ous phe­nom­e­non known as “defau­na­tion”. The future of bio­di­ver­si­ty depends to a large extent on the type of agri­cul­ture that is devel­oped, and con­verse­ly, the future of agri­cul­ture depends on agri­cul­tur­al bio­di­ver­si­ty. It should be remem­bered that every year, $235–577bn of agri­cul­tur­al pro­duc­tion world­wide is at risk because of the dis­ap­pear­ance of pollinators.

We often talk about the use of agro-ecol­o­gy to lim­it the envi­ron­men­tal impact of agri­cul­ture… But what is it?

Agri­cul­ture has devel­oped on the basis of an indus­tri­al mod­el, with uni­for­mi­ty and stan­dard­i­s­a­tion of prac­tices. But from a sci­en­tif­ic point of view, this approach is ill-suit­ed to the diver­si­ty of agri­cul­tur­al land­scapes. You can’t grow maize and soya every­where, or there will be seri­ous envi­ron­men­tal impacts! Agri­cul­tur­al pro­duc­tion is not diverse enough because some farms stick to very basic rota­tion sys­tems, such as the maize/soya com­bi­na­tion, where­as they should be made more com­plex, with legumes and longer rota­tions to max­imise the syn­er­gies in each crop.

Biodiversité agricole
Bio­di­ver­si­ty decline in agri­cul­tur­al land due to land use inten­si­fi­ca­tion. Source: EASAC1.

Agroe­col­o­gy is a mod­el that takes into account eco­log­i­cal process­es and bio­di­ver­si­ty. It empha­sis­es crop diver­si­ty and the impor­tance of soil, fau­na and flo­ra bio­di­ver­si­ty; it inte­grates more eco­log­i­cal infra­struc­tures such as hedges, thick­ets, and ponds. Hedges and thick­ets are home to birds, pol­li­na­tors, and pest con­trol species such as par­a­sitoids and ground bee­tles. It is also nec­es­sary to reduce the size of the plots. The entire organ­i­sa­tion of farms must there­fore be reconsidered.

To do so, it is nec­es­sary to cre­ate rel­e­vant and ambi­tious finan­cial and oth­er incen­tives. We need to go fur­ther than the Com­mon Agri­cul­tur­al Pol­i­cy (CAP)2.

What about the soil? Is it a ques­tion of cul­ti­vat­ing it less?

In real­i­ty, this is a com­pli­cat­ed ques­tion, which is not sci­en­tif­i­cal­ly clear-cut. Work­ing the soil less deeply allows us to ben­e­fit more from the work of micro-organ­isms and earth­worms. How­ev­er, it can help with weed con­trol and improve soil aer­a­tion… The bal­ance between all these fac­tors is there­fore com­plex to find. But the stakes are high: soil degra­da­tion has reduced the pro­duc­tiv­i­ty of the entire world’s land sur­face by 23%.

Agri­cul­ture is also being called upon to pro­vide energy…

But the sus­tain­abil­i­ty of this is being called into ques­tion. Pro­duc­ing addi­tion­al crops for first-gen­er­a­tion agro­fu­els (bioethanol, biodiesel) has many impacts on bio­di­ver­si­ty. Mak­ing bio­fu­els or bio­gas from waste also has its lim­its, as its avail­abil­i­ty is prob­a­bly not that great. For exam­ple, there is lit­tle organ­ic waste on a farm. Straw, for exam­ple, is used in ani­mal hus­bandry or to regen­er­ate the soil: it is a pre­cious com­mod­i­ty! Agri­cul­ture is thus essen­tial­ly a recy­cling economy.

Soil degra­da­tion has reduced the pro­duc­tiv­i­ty of the entire world’s land sur­face by 23%.

More and more farm­ers are invest­ing in bio­methanis­ers, instal­la­tions that pro­duce bio­gas from plant prod­ucts or live­stock manure. This is cur­rent­ly extreme­ly prof­itable, as it is sup­port­ed by sub­si­dies. But is it real­ly worth­while from an eco­log­i­cal point of view, espe­cial­ly if crops are grown specif­i­cal­ly to fuel them?

But then, is agroe­col­o­gy also organ­ic farm­ing? Sus­tain­able agri­cul­ture? Con­ser­va­tion agriculture?

It is indeed an “umbrel­la: con­cept that cov­ers all these prac­tices and many oth­ers. It remains dif­fi­cult to assess the advan­tages and dis­ad­van­tages of each prac­tice from a sci­en­tif­ic point of view. They can all con­tribute to reduc­ing the impact of agri­cul­ture on bio­di­ver­si­ty. The Euro­pean Acad­e­my of Sci­ences pro­pos­es yet anoth­er vari­ant, “regen­er­a­tive agriculture”.

Degree of land­scape sim­pli­fi­ca­tion due to agri­cul­tur­al inten­si­fi­ca­tion. Source: EASAC3.

These prac­tices engage us as con­sumers but also as cit­i­zens. We need to ensure that our pub­lic poli­cies sup­port envi­ron­men­tal­ly and social­ly rel­e­vant agri­cul­tur­al prac­tices. But it isn’t easy! Agroe­col­o­gy requires more work, and there­fore more labour on the farm. This will inevitably have an impact on the price of prod­ucts, which may be dif­fi­cult for con­sumers to accept – polit­i­cal sup­port is needed.

So polit­i­cal will is key. There is now talk of an agri­cul­tur­al Green Deal on a Euro­pean scale, is this good news?

This is a very rel­e­vant con­tri­bu­tion pro­duced by the Pres­i­den­cy of the Euro­pean Union, while the CAP has just been reformed by the Euro­pean Com­mis­sion for the next five years… in a rather dif­fer­ent vein from the Green Deal. So, we cur­rent­ly have two com­pet­ing agri­cul­tur­al philoso­phies in Europe, which need to be reconciled.

Interview by Agnès Vernet

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