Intensive Agriculture Blamed for Bird Population Decline in Spain

The lat­est Atlas of Breeding Birds in Spain shows a pop­u­la­tion decline of about 27 per­cent in birds linked to agri­cul­tural envi­ron­ments.

The inten­si­fi­ca­tion of farm­ing meth­ods is the dri­ving force, accord­ing to SEO/BirdLife, with super-high-den­sity olive groves being par­tic­u­larly detri­men­tal to key species.

SEO/BirdLife noted that although such a sig­nif­i­cant aver­age decline is deeply con­cern­ing, many indi­vid­ual species have suf­fered even more sig­nif­i­cant losses.

The rufous-tailed scrub robin, for exam­ple, saw a decline of nearly 95 per­cent since 2003; the lit­tle bus­tard, about 69 per­cent from 1998 to 2018; and the black-bel­lied sand­grouse, 34 per­cent between 2005 and 2009.

The most sig­nif­i­cant over­all threats to all three of these species in Spain are rooted in wide­spread changes to agri­cul­tural meth­ods.

Previous research showed that farm­land is the most impor­tant habi­tat for bird con­ser­va­tion in Europe, har­bor­ing more than 50 per­cent of bird species in the European Union and 55 per­cent of European bird species on the International Union for Conservation of Nature’s Red List.

The Iberian penin­sula is par­tic­u­larly impor­tant to many endan­gered and vul­ner­a­ble species, with some 60 per­cent of the sur­viv­ing global pop­u­la­tion of the great bus­tard now con­fined to Spain and Portugal, for exam­ple.

The inten­si­fi­ca­tion of agri­cul­ture has changed the Spanish land­scape rad­i­cally in recent decades. With increased pro­duc­tiv­ity as its sole dri­ving force, it has led to the mas­sive expan­sion of mono­cul­tures, the reduc­tion of wild and fal­low areas, the trans­for­ma­tion of large areas of dry land into irri­gated land, and the wide­spread use of pes­ti­cides and her­bi­cides.

These fac­tors have decreased the quan­tity and qual­ity of ter­ri­tory avail­able to wildlife in gen­eral and birds in par­tic­u­lar.

Monocultures, by def­i­n­i­tion, reduce bio­di­ver­sity, lead­ing to fewer plants with seeds as a food source, fewer places to breed and less shel­ter from preda­tors and the ele­ments.

In the case of super-high-den­sity olive groves, immense tracts of land are used mostly for uni­form rows of olive trees and much of the other veg­e­ta­tion is removed.

Not only does this cre­ate an envi­ron­ment hos­tile to wildlife, but it also involves the destruc­tion of the exist­ing envi­ron­ment, lead­ing to the death or dis­place­ment of the entire local ecosys­tem.

As many species of bird are migra­tory, com­plex and long-estab­lished migra­tion routes can also be inter­rupted or irrev­o­ca­bly bro­ken.

Over the same period, the sig­nif­i­cant decline in European insects has also affected bird pop­u­la­tions since approx­i­mately 60 per­cent of all known bird species are at least partly insec­tiv­o­rous.

A 2017 analy­sis esti­mated a sea­sonal decline of 76 per­cent and a mid-sum­mer decline of 82 per­cent in fly­ing insect bio­mass since 1990.

The exact causes of this decline remain unre­solved. Still, the study’s authors noted that ​“agri­cul­tural inten­si­fi­ca­tion, includ­ing the dis­ap­pear­ance of field mar­gins and new crop pro­tec­tion meth­ods, has been asso­ci­ated with an over­all decline of bio­di­ver­sity in plants, insects, birds and other species in the cur­rent land­scape.”

In addi­tion to the gen­eral decline of fly­ing insects, inten­sive farm­ing meth­ods result in dras­ti­cally reduced num­bers of local ground prey species such as spi­ders, cater­pil­lars and grasshop­pers.

This results from the same fac­tors that make the envi­ron­ments hos­tile to the birds, most notably lack of ground cover, an engi­neered mono­cul­ture, uni­for­mity of land­scape and increased use of arti­fi­cial her­bi­cides, pes­ti­cides and fer­til­iz­ers.

The land­scape has been fur­ther altered by the con­struc­tion of vast indus­trial and trans­port infra­struc­tures and, more recently, renew­able energy instal­la­tions such as pho­to­voltaic and wind farms.

Due to their com­mer­cial nature, many of these projects are sited on land deemed ​“unpro­duc­tive” by humans but vital to other species as their nat­ural habi­tats.

Discussing the impli­ca­tions for the new Common Agricultural Policy (CAP) in 2022, José Eugenio Gutiérrez, del­e­gate of SEO/BirdLife in Andalusia and head of the Life Olivares Vivos+ project, said that ​“to con­serve our nat­ural her­itage… 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.”

The Olivares Vivos farm­ing model, based on research car­ried out by the ecol­ogy depart­ment of the University of Jaén and the Arid Zones Experimental Station of the Spanish National Research Council 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 restor­ing so-called ​“unpro­duc­tive areas” in olive groves such as gul­lies, streams, tracks, and walls.

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 agri­cul­tural bird species when cre­at­ing agri­cul­tural and envi­ron­men­tal poli­cies.

• SEO/Bird Life