Urbanization impacts on the trophic guild composition of bird communities

CRISTALDI, MAXIMILIANO; GIRAUDO, ALEJANDRO R; ARZAMENDIA VANESA; BELLINI, GISELA P.

JOURNAL OF NATURAL HISTORY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2017 vol. 51 p. 2385 - 2404

0022-2933

Urbanization transforms the landscape and generates loss ofpristine habitats. We investigated the urbanization effect onbird communities in a growing South American city (Santa Fe,Argentina) and hypothesized that if habitat structure andhuman disturbance change along an urban gradient, the richnessand abundance of trophic guilds should also vary accordingly.We placed 50 transects 100 m long × 50 m wide in fivedistricts with different levels of urbanization, determined byhabitat structure variables. We recorded the number and abundanceof species and the amount of pedestrians and vehiclespassing through each transect. We recorded 23% of all birdspecies known for the Santa Fe province and categorizedthem within 19 trophic guilds. The percentage of area coveredby herbaceous vegetation, water bodies and trees and shrubshad a positive relationship with the richness and abundance ofmost of trophic guilds (hawking aerial, terrestrial, bark andfoliage insectivores; terrestrial and generalized granivores; generalized,aquatic diving and foliage omnivores; hawking aerial,aquatic diving and striding carnivores; nectarivores; and aquaticfilters). Pavement surface and human disturbance variables hada negative relationship with the richness, and high buildingsand pavement surface had a positive relationship with theabundance of terrestrial omnivores and coursing aerial insectivores.Variation partitioning revealed that habitat structure andhuman disturbance were better predictors of the richness thanthe abundance of each trophic guild. Results showed thattrophic guilds associated to vegetation strata were seen toincrease their richness and abundance towards green areas,even if they presented generalist or specialist habits. Urbanplanners should conserve or manage the surrounded naturalspaces when the growth of the city is directed to these areasand increase the availability of environmental features withinthe urban matrix.