`Researchers Reintroduce Bats to Andalusian Olive Groves to Combat Pests - Olive Oil Times

Researchers Reintroduce Bats to Andalusian Olive Groves to Combat Pests

By Simon Roots
May. 4, 2022 13:11 UTC

After eval­u­at­ing the results of bat rein­tro­duc­tion across the Iberian penin­sula, the LIFE Olivares Vivos+ project announced the expan­sion of this ini­tia­tive due to the com­bi­na­tion of effec­tive olive pest reduc­tion and the sub­se­quent eco­log­i­cal and finan­cial ben­e­fits stem­ming from reduced use of arti­fi­cial pes­ti­cides and fer­til­iz­ers.

The ini­tia­tive was born in 2019 when a research team from the University of Évora, Portugal, con­ducted a series of sem­i­nars in Spain on the effi­cacy of bats as nat­ural pest con­trollers, high­light­ing their poten­tial as an eco­nom­i­cal and sus­tain­able alter­na­tive to the use of chem­i­cal prod­ucts.

During their visit, the team stud­ied the LIFE Olivares Vivos+ demon­stra­tion olive grove at Virgen de los Milagros, Jaén. Using pur­pose-built instru­ments and com­puter soft­ware, they iden­ti­fied between six and 10 dis­tinct bat species in the grove over the course of a sin­gle night.

See Also:Conservationists Hope to Replicate Success of Biodiversity Project in Northeast Spain

The rel­a­tively high num­ber of bats detected was attrib­uted to the Olivares Vivos olive farm­ing model, which is based on research car­ried out by the ecol­ogy depart­ment of the University of Jaén in con­junc­tion with the Arid Zones Experimental Station of the Spanish National Research Council.

This model seeks to reduce the neg­a­tive envi­ron­men­tal impact of olive farm­ing while increas­ing bio­di­ver­sity. This is accom­plished by intro­duc­ing non-crop native species, installing sup­port infra­struc­tures for fauna such as ponds, nest­ing boxes and fenc­ing posts; and the restora­tion of so-called unpro­duc­tive areas” in olive groves such as gul­lies, streams, tracks and walls.

These dif­fer­ences between the Olivares Vivos model and the largely uni­form high-den­sity and super-high-den­sity groves, now com­mon around the world, are vital to sup­port­ing insec­tiv­o­rous bats as, with­out envi­ron­men­tal vari­a­tion, echolo­ca­tion is inef­fec­tive.

A major study car­ried out by researchers from the University of Évora demon­strated that struc­tural sim­pli­fi­ca­tion dif­fer­en­tially influ­ences the activ­ity pat­terns of both insec­tiv­o­rous bats and insect pests within olive groves. Moreover, it sug­gested that struc­tural sim­pli­fi­ca­tion may strongly com­pro­mise bio­log­i­cal con­trols pro­vided by bats on major olive pests such as the olive fruit moth.

The vis­it­ing researchers con­cluded that the Olivares Vivos model rep­re­sents an excel­lent habi­tat for many species of bats, many of which are threat­ened or endan­gered in the region.

Since then, the two orga­ni­za­tions have col­lab­o­rated to improve the model fur­ther, specif­i­cally incor­po­rat­ing bat con­ser­va­tion into its objec­tives. New mea­sures result­ing from this col­lab­o­ra­tion include the intro­duc­tion of posts sev­eral meters high with a vari­ety of attached struc­tures to serve as shel­ter and nest­ing loca­tions.

Not only do these encour­age bats of var­i­ous species to col­o­nize the area, but they also serve as valu­able echolo­ca­tion ref­er­ence points sim­i­lar to land­marks. Such ref­er­ence points are impor­tant to bats’ abil­ity to map and effec­tively nav­i­gate the ter­ri­tory.

As with all Project LIFE ini­tia­tives, the rein­tro­duc­tion of bats to olive groves has very clear prac­ti­cal and eco­nomic objec­tives in addi­tion to those con­cern­ing the envi­ron­ment.

A sin­gle indi­vid­ual will typ­i­cally con­sume between 6,000 and 8,000 insects of vary­ing sizes and species per night. This means that although groves fol­low­ing the model con­tain a far greater degree of bio­log­i­cal diver­sity, reduc­ing pest species such as the olive fruit fly is still sig­nif­i­cant.

In addi­tion, bat guano is extremely rich in nitrates, to the extent that it has often been mined from caves world­wide for agri­cul­tural use.

This con­fers a fur­ther eco­nomic ben­e­fit to farm­ers through reduced input costs, as the very pests which the bats con­sume are then trans­formed into an effi­cient and envi­ron­men­tally-friendly fer­til­izer.

The encour­ag­ing results of the research to date also have pos­i­tive impli­ca­tions for the expan­sion of Project LIFE beyond Spain and into the Alentejo region of Portugal, the regions of Tuscany and Puglia in Italy; and both the Peloponnese and Crete in Greece.

All of these areas have both local and migra­tory bat pop­u­la­tions and are home to var­i­ous vul­ner­a­ble or threat­ened species that can ben­e­fit from this and sim­i­lar ini­tia­tives.


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