title: Mismatch in microbial food webs: predators but not prey perform better in their local biotic and abiotic conditions.
abstract: Understanding how trophic levels respond to changes in abiotic and biotic conditions is key for predicting how food webs will react to environmental perturbations. Different trophic levels may respond disproportionately to change, with lower levels more likely to react faster, as they typically consist of smaller-bodied species with higher reproductive rates. This response could cause a mismatch between trophic levels, in which predators and prey will respond differently to changing abiotic or biotic conditions. This mismatch between trophic levels could result in altered top-down and bottom-up control and changes in interaction strength. To determine the possibility of a mismatch, we conducted a reciprocal-transplant experiment involving Sarracenia purpurea food webs consisting of bacterial communities as prey and a subset of six morphologically similar protozoans as predators. We used a factorial design with four temperatures, four bacteria and protozoan biogeographic origins, replicated four times. This design allowed us to determine how predator and prey dynamics were altered by abiotic (temperature) conditions and biotic (predators paired with prey from either their local or non-local biogeographic origin) conditions. We found that prey reached higher densities in warmer temperature regardless of their temperature of origin. Conversely, predators achieved higher densities in the temperature condition and with the prey from their origin. These results confirm that predators perform better in abiotic and biotic conditions of their origin while their prey do not. This mismatch between trophic levels may be especially significant under climate change, potentially disrupting ecosystem functioning by disproportionately affecting top-down and bottom-up control.
authors.affiliation: Department of Biology - Ecology and EvolutionUniversity of Fribourg Chemin du Musée 101700 Fribourg Switzerland; Department of Ecology and Evolutionary Ecology Yale University 165 Prospect Street New Haven Connecticut 06520.
authors.forename: Elodie C
authors.initials: EC
authors.lastname: Parain
authors.affiliation: Département de Biologie, Chimie et Géographie Université du Québec à Rimouski 300 Allée des Ursulines Rimouski Quebec G5L 3A1 Canada; Département de Biologie - Ecologie Terrestre Université de Sherbrooke 2500, boulevard de l'Université Sherbrooke Quebec J1K 2R1 Canada.
authors.forename: Dominique
authors.initials: D
authors.lastname: Gravel
authors.affiliation: Department of Biology - Ecology and Evolution University of Fribourg Chemin du Musée 10 1700 Fribourg Switzerland.
authors.forename: Rudolf P
authors.initials: RP
authors.lastname: Rohr
authors.affiliation: Department of Biology - Ecology and Evolution University of Fribourg Chemin du Musée 10 1700 Fribourg Switzerland.
authors.forename: Louis-Félix
authors.initials: LF
authors.lastname: Bersier
authors.affiliation: Department of Biology - Ecology and Evolution University of Fribourg Chemin du Musée 10 1700 Fribourg Switzerland.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Gray
keywords: Consumer‐resource; Sarracenia purpurea; predator–prey; reciprocal‐transplant experiment; temperature