Browsing by large herbivores might either increase or decrease preference for the plant by other herbivores,depending on the plant response.Using a cafeteria test,we studied the preference by root voles(Microtus oecon...Browsing by large herbivores might either increase or decrease preference for the plant by other herbivores,depending on the plant response.Using a cafeteria test,we studied the preference by root voles(Microtus oeconomus[Pallas,1776])for bilberry(Vaccinium myrtillus L.)previously subjected to 4 levels of simulated moose(Alces alces[Linnaeus,1758])density.The different levels of moose density were simulated at population densities relevant for Fennoscandian conditions,in exclosures situated along a site productivity gradient.We expected:(i)voles to prefer bilberry from high productivity sites over low productivity sites;(ii)voles to prefer browsed bilberry,if plants allocate resources to compensatory growth or to avoid browsed bilberry if plants allocate resources to defense;(iii)these effects to increase with increasing simulated moose density;and(iv)the concentration of plant chemicals and the plant morphology to explain vole preference.Specifically,we predicted that voles would prefer:(i)plants with high nitrogen content;(ii)plants with low content of defensive substances;and(iii)tall plants with long shoots.Voles preferred bilberry from the high productivity sites compared to the low productivity sites.We also found an interaction between site productivity and simulated moose density,where voles preferred unbrowsed plants at low productivity sites and intermediate levels of browsing at high productivity sites.There was no effect of plant chemistry or morphology on vole preference.We conclude that moose browsing impacts the food preference of voles.With the current high densities of moose in Fennoscandia,this could potentially influence vole food selection and population dynamics over large geographical areas.展开更多
基金This study was funded by Hedmark University College.The moose simulation experiment,including sampling of bilberry used in this experiment,was financed by the Swedish Research Council for Environmental,Agricultural Sciences and Spatial Planning,and the Swedish Environmental Protection Agency(grants to I-L Persson and K Danell)The forest companies Assi Domän/Sveaskog and Holmen Skog kindly allowed us to work on their land.The study was conducted in accordance with current Norwegian and Swedish laws,under the necessary permits(2007/11612 ART-VI-ID and STFDU1058).
文摘Browsing by large herbivores might either increase or decrease preference for the plant by other herbivores,depending on the plant response.Using a cafeteria test,we studied the preference by root voles(Microtus oeconomus[Pallas,1776])for bilberry(Vaccinium myrtillus L.)previously subjected to 4 levels of simulated moose(Alces alces[Linnaeus,1758])density.The different levels of moose density were simulated at population densities relevant for Fennoscandian conditions,in exclosures situated along a site productivity gradient.We expected:(i)voles to prefer bilberry from high productivity sites over low productivity sites;(ii)voles to prefer browsed bilberry,if plants allocate resources to compensatory growth or to avoid browsed bilberry if plants allocate resources to defense;(iii)these effects to increase with increasing simulated moose density;and(iv)the concentration of plant chemicals and the plant morphology to explain vole preference.Specifically,we predicted that voles would prefer:(i)plants with high nitrogen content;(ii)plants with low content of defensive substances;and(iii)tall plants with long shoots.Voles preferred bilberry from the high productivity sites compared to the low productivity sites.We also found an interaction between site productivity and simulated moose density,where voles preferred unbrowsed plants at low productivity sites and intermediate levels of browsing at high productivity sites.There was no effect of plant chemistry or morphology on vole preference.We conclude that moose browsing impacts the food preference of voles.With the current high densities of moose in Fennoscandia,this could potentially influence vole food selection and population dynamics over large geographical areas.
