TY  - JOUR
A1  - Koussoroplis, Apostolos-Manuel
A1  - Pincebourde, Sylvain
A1  - Wacker, Alexander
T1  - Understanding and predicting physiological performance of organisms in fluctuating and multifactorial environments
JF  - Ecological monographs : a publication of the Ecological Society of America.
N2  - Understanding how variance in environmental factors affects physiological performance, population growth, and persistence is central in ecology. Despite recent interest in the effects of variance in single biological drivers, such as temperature, we have lacked a comprehensive framework for predicting how the variances and covariances between multiple environmental factors will affect physiological rates. Here, we integrate current theory on variance effects with co-limitation theory into a single unified conceptual framework that has general applicability. We show how the framework can be applied (1) to generate mathematically tractable predictions of the physiological effects of multiple fluctuating co-limiting factors, (2) to understand how each co-limiting factor contributes to these effects, and (3) to detect mechanisms such as acclimation or physiological stress when they are at play. We show that the statistical covariance of co-limiting factors, which has not been considered before, can be a strong driver of physiological performance in various ecological contexts. Our framework can provide powerful insights on how the global change-induced shifts in multiple environmental factors affect the physiological performance of organisms.
KW  - co-limitation
KW  - covariance
KW  - eco-physiology
KW  - feeding rate
KW  - global change
KW  - multiple stressors
KW  - nonlinear averaging
KW  - nutrients
KW  - scale transition
KW  - temperature
KW  - temporal ecology
KW  - variance
Y1  - 2017
U6  - https://doi.org/10.1002/ecm.1247
SN  - 0012-9615
SN  - 1557-7015
VL  - 87
SP  - 178
EP  - 197
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Koussoroplis, Apostolos-Manuel
A1  - Schälicke, Svenja
A1  - Raatz, Michael
A1  - Bach, Moritz
A1  - Wacker, Alexander
T1  - Feeding in the frequency domain
BT  - Coarser-grained environments increase consumer sensitivity to resource variability, covariance and phase
JF  - Ecology letters
N2  - Theory predicts that resource variability hinders consumer performance. How this effect depends on the temporal structure of resource fluctuations encountered by individuals remains poorly understood. Combining modelling and growth experiments with Daphnia magna, we decompose the complexity of resource fluctuations and test the effect of resource variance, supply peak timing (i.e. phase) and co-limiting resource covariance along a gradient from high to low frequencies reflecting fine- to coarse-grained environments. Our results show that resource storage can buffer growth at high frequencies, but yields a sensitivity of growth to resource peak timing at lower ones. When two resources covary, negative covariance causes stronger growth depression at low frequencies. However, negative covariance might be beneficial at intermediate frequencies, an effect that can be explained by digestive acclimation. Our study provides a mechanistic basis for understanding how alterations of the environmental grain size affect consumers experiencing variable nutritional quality in nature.
KW  - Cholesterol
KW  - covariance
KW  - Daphnia
KW  - digestive acclimation
KW  - dynamic energy budgets
KW  - food quality
KW  - phosphorus
KW  - storage
KW  - unbalanced diets
Y1  - 2019
U6  - https://doi.org/10.1111/ele.13267
SN  - 1461-023X
SN  - 1461-0248
VL  - 22
IS  - 7
SP  - 1104
EP  - 1114
PB  - Wiley
CY  - Hoboken
ER  -