Predicting population responses to environmental change from individual-level mechanisms: towards a standardized mechanistic approach

Abstract

Animal populations will mediate the response of global biodiversity to environmental changes. Population models are thus important tools for both understanding and predicting animal responses to uncertain future conditions. Most approaches, however, are correlative and ignore the individual-level mechanisms that give rise to population dynamics. Here, we assess several existing population modelling approaches and find limitations to both ‘correlative’ and ‘mechanistic’ models. We advocate the need for a standardized mechanistic approach for linking individual mechanisms (physiology, behaviour, and evolution) to population dynamics in spatially explicit landscapes. Such an approach is potentially more flexible and informative than current population models. Key to realizing this goal, however, is overcoming current data limitations, the development and testing of eco-evolutionary theory to represent interactions between individual mechanisms, and standardized multi-dimensional environmental change scenarios which incorporate multiple stressors. Such progress is essential in supporting environmental decisions in uncertain future conditions.

Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

“…For instance, growth and development rates among female wood frog larvae are more sensitive to temperature than in their male counterparts (Lambert et al, 2018). Recognizing sources of within‐individual variation in thermal traits across ontogeny is paramount to predicting population responses to environmental changes (Agudelo‐Cantero & Navas, 2019; Johnston et al, 2019; Klockmann et al, 2017; Pincebourde & Casas, 2015). For example, vulnerability assessments may integrate measures of thermal traits across ontogeny to detect which stages or life‐history transitions are at greater risk of suffering climate change impacts.…”

Thermal Plasticity in Insects’ Response to Climate Change and to Multifactorial Environments

“…The ability of natural populations to react to environmental change will depend on the level and type of perturbation organisms experience, and also on their intrinsic capability to respond to it (Parmesan, 2006;Johnston et al, 2019). Phenotypic plasticity, the property by which living organisms express different phenotypes depending on environmental conditions, can impact their response to environmental perturbation, including that resulting from global climate change (Reed et al, 2011;Chevin et al, 2013;Merilä and Hendry, 2014;Sgrò et al, 2016;Bonamour et al, 2019).…”

Modeling Climatic Influences on Three Parasitoids of Low-Density Spruce Budworm Populations. Part 1: Tranosema rostrale (Hymenoptera: Ichneumonidae)

“…Modeling population-level interactions between trophic levels at the seasonal time scale is very well suited to individual-base modeling approaches, because it can handle multidimensional change scenarios and complex interactions [70]. In this paper, we showed that the timing of its first generation of adults that attack feeding larvae of the SBW [24] is most consistent with the hypothesis that the parasitoid overwinters as an egg or as a very young larva inside a diapausing larval host, a strategy known to be that of the other two parasitoids species that constitute this series: Actia interrupta [unpublished data of J.-C.T.]…”