Research article - Peer-reviewed, 2017
Enhanced leaf nitrogen status stabilizes omnivore population density
Liman, Anna-Sara; Dalin, Peter; Bjorkman, ChristerAbstract
Plant traits can mediate the strength of interactions between omnivorous predators and their prey through density effects and changes in the omnivores' trophic behavior. In this study, we explored the established assumption that enhanced nutrient status in host plants strengthens the buffering effect of plant feeding for omnivorous predators, i.e., prevents rapid negative population growth during prey density decline and thereby increases and stabilizes omnivore population density. We analyzed 13 years of field data on population densities of a heteropteran omnivore on Salix cinerea stands, arranged along a measured leaf nitrogen gradient and found a 195 % increase in omnivore population density and a 63 % decrease in population variability with an increase in leaf nitrogen status from 26 to 40 mgN x g(-1). We recreated the leaf nitrogen gradient in a greenhouse experiment and found, as expected, that increasing leaf nitrogen status enhanced omnivore performance but reduced per capita prey consumption. Feeding on high nitrogen status host plants can potentially decouple omnivore-prey population dynamics and allow omnivores to persist and function effectively at low prey densities to provide "background level" control of insect herbivores. This long-term effect is expected to outweigh the short-term effect on per capita prey consumption-resulting in a net increase in population predation rates with increasing leaf nitrogen status. Conservation biological control of insect pests that makes use of omnivore background control could, as a result, be manipulated via management of crop nitrogen status.Keywords
Plant traits; Trophic omnivory; Population dynamics; Trophic status; Leaf nitrogenPublished in
Oecologia2017, volume: 183, number: 1, pages: 57-65
Authors' information
Liman, Anna-Sara
Swedish University of Agricultural Sciences, Department of Ecology
Dalin, Peter
Swedish University of Agricultural Sciences, Department of Ecology
Swedish University of Agricultural Sciences, Department of Ecology
Associated SLU-program
SLU Future Forests
SLU Network Plant Protection
UKÄ Subject classification
Ecology
Publication Identifiers
DOI: https://doi.org/10.1007/s00442-016-3742-y
URI (permanent link to this page)
https://res.slu.se/id/publ/79267