Olive Grove Expansion Threatens Endangered Bird Species in Spain

According to researchers from the University of Córdoba and Ecuador’s Technical University of Manabí, the expan­sion of olive groves in Andalusia is impact­ing the habi­tat of the already scarce pop­u­la­tions of Eurasian great bus­tard and lit­tle bus­tard.

In a research arti­cle pub­lished in Bird Conservation International, the team eval­u­ated the per­cent­age of dif­fer­ent land uses between 2000 and 2018 using data from the Corine Land Cover inven­tory, a pan-European satel­lite land sur­vey data­base, con­cern­ing the birds’ nat­ural habi­tats and known ranges.

They found that over this period, new olive groves occu­pied 2.14 per­cent and 2.61 per­cent of the Andalusian range of the Eurasian great bus­tard and lit­tle bus­tard, respec­tively.

Though pre­vi­ously wide­spread through­out Eurasia, from the British Isles to China, some 60 per­cent of the sur­viv­ing pop­u­la­tion of the great bus­tard is now con­fined to the Iberian penin­sula.

The lit­tle bus­tard has suf­fered a sim­i­lar fate. Once breed­ing as far north as Poland, it has become extinct in its for­mer cen­tral-European range over the past few decades.

All bus­tards are nat­u­rally grass­land and steppe birds but are well-suited to open arable farm­land. It is the con­ver­sion of such farm­land to olive groves and other woody crop­land that the authors believe may threaten the species’ future, not only because of over­all habi­tat reduc­tion but also because of habi­tat frag­men­ta­tion.

Though capa­ble of fly­ing vast dis­tances, bus­tards are pri­mar­ily ground-dwelling and feed by for­ag­ing on veg­e­ta­tion and insects.

Iberian flocks of the great bus­tard, in par­tic­u­lar, appear to migrate only very rarely, and even then for rel­a­tively short dis­tances in response to extremes of tem­per­a­ture.

Therefore, ​“these changes in land­scape con­fig­u­ra­tion sug­gest a decline in both habi­tat avail­abil­ity and habi­tat qual­ity for steppe birds that could affect their dis­tri­b­u­tion and pop­u­la­tion size,” the researchers wrote.

“This arti­cle accu­rately shows the impact of habi­tat loss in cereal agrosys­tems in favor of woody crops, in this case, olive groves,” said José Eugenio Gutiérrez, a del­e­gate of SEO/BirdLife in Andalusia and head of the Life Olivares Vivos+ project. ​“It exposes the effect of this habi­tat loss on the great bus­tard and the lit­tle bus­tard, some­thing we already knew, but to which this inter­est­ing sci­en­tific work puts fig­ures.”

“Although the expan­sion of olive groves in the last two decades has not been so impor­tant quan­ti­ta­tively… it has been qual­i­ta­tively because it has occurred at the expense of farm­land [pre­vi­ously] ded­i­cated to cereal crops and has had an impact on the loss and frag­men­ta­tion of habi­tat that has added to that accu­mu­lated over pre­vi­ous decades,” he added.

Of par­tic­u­lar con­cern to con­ser­va­tion groups such as SEO/BirdLife is the authors’ obser­va­tion that ​“no dif­fer­ences were found in the pro­por­tion of new olive groves planted inside and out­side of Important Bird and Biodiversity Areas (IBAs) from 2000 to 2018, specif­i­cally des­ig­nated to con­serve these steppe birds.”

“This leads us to think that con­ser­va­tion pol­icy should be reviewed and improved to pre­vent changes in land use from being detri­men­tal to dif­fer­ent species,” they added.

In response to this and other stud­ies, both SEO/BirdLife and the Life Olivares Vivos+ project have made numer­ous rec­om­men­da­tions to regional, national, and E.U. gov­ern­ment bod­ies regard­ing the need to con­sider the habi­tats of steppe species when cre­at­ing agri­cul­tural and envi­ron­men­tal pol­icy.

Discussing the impli­ca­tions for the new Common Agricultural Policy (CAP), Gutiérrez affirmed his belief that ​“to con­serve our nat­ural her­itage (and, as we are see­ing, to improve our food inde­pen­dence), stop­ping this trans­for­ma­tion of farm­land into woody crop­land or solar pho­to­voltaic plants is a top pri­or­ity that must go through ade­quate strate­gic plan­ning at the ter­ri­to­r­ial level, and com­pli­ance with the envi­ron­men­tal objec­tives of the new CAP.”

“Biodiversity con­ser­va­tion can­not fall entirely on the shoul­ders of these farm­ers who resist change, and until the agri-food mar­ket (and con­sumers) have incor­po­rated bio­di­ver­sity into the rules of the game, it is time for agri­cul­tural pol­icy,” he added.

SEO/BirdLife said that if ade­quate man­age­ment plans are in place, the impact can be mit­i­gated. For exam­ple, in those cases where olive groves and arable land are inter­spersed in the so-called ​“mosaic” land­scape that pro­vides an over­all ben­e­fit to bio­di­ver­sity, includ­ing birdlife.

• SEO/BirdLife
• Cambridge University Press