Habitat fragmentation and species loss across three interacting trophic levels: effects of life-history and food-web traits.
Not all species are likely to be equally affected by habitat fragmentation; thus, we evaluated the effects of size of forest remnants on trophically linked communities of plants, leaf-mining insects, and their parasitoids. We explored the possibility of differential vulnerability to habitat area reduction in relation to species-specific and food-web traits by comparing species-area regression slopes. Moreover, we searched for a synergistic effect of these traits and of trophic level. We collected mined leaves and recorded plant, leaf miner, and parasitoid species interactions in five 100-m2 transects in 19 Chaco Serrano woodland remnants in central Argentina. Species were classified into extreme categories according to body size, natural abundance, trophic breadth, and trophic level. Species-area slopes differed between groups with extreme values of natural abundance or trophic specialization. Nevertheless, synergistic effects of life-history and food-web traits were only found for trophic level and trophic breadth: area-related species loss was highest for specialist parasitoids. It has been suggested that species position within interaction webs could determine their vulnerability to extinction. Our results provide evidence that food-web parameters, such as trophic level and trophic breadth, affect species sensitivity to habitat fragmentation.
Cagnolo
Luciano
L
Centro de Investigaciones Entomológicas de Córdoba (IMBIV-CONICET), FCEFyN, Universidad Nacional de Córdoba, Avenida Vélez Sarsfield 1611 (X5016GCA), Cordoba, Argentina. lcagnolo@efn.uncor.edu
Valladares
Graciela
G
Salvo
Adriana
A
Cabido
Marcelo
M
Zak
Marcelo
M
D001118:Argentina; D017753:Ecosystem; D053476:Extinction, Biological; D020387:Food Chain; D013045:Species Specificity