Populations and assemblages living on the edge: dung beetles responses to forests-pasture ecotones

MARTÍNEZ-FALCÓN, ANA PAOLA; ZURITA, GUSTAVO A.; ORTEGA-MARTÍNEZ, ILSE J.; MORENO, CLAUDIA E.

PeerJ

PeerJ

Año: 2018 vol. 6

Edge effects alter insect biodiversity in several ways. However, we still have a limitedunderstanding on simultaneous responses of ecological populations and assemblagesto ecotones, especially in human modified landscapes. We analyze edge effectson dung beetle populations and assemblages between livestock pastures and nativetemperate forests (Juniperus and pine-oak forests (POFs)) to describe howspecies abundances and assemblage parameters respond to edge effects throughgradients in forest-pasture ecotones. In Juniperus forest 13 species avoided theecotones: six species showed greater abundance in forest interior and sevenin pasturelands, while the other two species had a neutral response to the edge.In a different way, in POF we found five species avoiding the edge (four with greaterabundance in pastures and only one in forest), two species had a neutral response,and two showed a unimodal pattern of abundance near to the edge. At theassemblage level edge effects are masked, as species richness, diversity, functionalrichness, functional evenness, and compositional incidence dissimilarity did notvary along forest-pasture ecotones. However, total abundance and functionaldivergence showed higher values in pastures in one of the two sampling localities.Also, assemblage similarity based on species? abundance showed a peak near tothe edge in POF. We propose that conservation efforts in human-managedlandscapes should focus on mitigating current and delayed edge effects.Ecotone management will be crucial in livestock dominated landscapes to conserveregional biodiversity and the environmental services carried out by dung beetles.