Experimental population of soil mites Sancassania berlesei. Past environments shape the distribution of phenotypic traits via selection and plasticity. One such trait, individual body
size is commonly used in size-dependent demographic analyses to represent the effect of the environment on vital rates. However, experimental populations of soil mites maintained in different food environments revealed that the strength of body size as a proxy for past and current environmental effects can vary vastly among vital rates (see Brooks et al.). Photo by Marianne Mugabo.

This exciting collaborative and interdisciplinary special feature integrates novel lines of research in the vast field of demography that directly interact with other ecological and evolutionary disciplines.

The goal of the special feature is to highlight the interdisciplinary potential of demography and is further emphasised by the fact that the 21 articles are spread across all six journals of the British Ecological Society.

The goal of the Special Feature is to highlight to both demographers and non-demographers alike that there is much to be gained by linking demography to other disciplines and scales in ecology and evolution.

The Special Feature is based on a British Ecological Society symposium that was held in March 2015 and is the first time all six BES journals have collaborated to produce a joint special feature.

Journal of Animal Ecology has published 4 papers in the Special Feature:

Disentangling correlated explanatory variables

In this paper Brooks et al. discus how the the strength of size as a proxy for past environments varies among vital rates. They quantified this using a novel method for understanding nonlinear relationships between responses and multicollinear predictors. This non-mechanistic model has the strength of being flexible enough to apply in data-limited situations and will be useful for identifying patterns and generating hypotheses.

The evolution of labile traits in sex- and age-structured populations

Childs et al. present a data-driven framework that  has the potential to facilitate greater insight into the nature of selection and its consequences in settings where focal traits vary over the lifetime through ontogeny, behavioural adaptation and phenotypic plasticity, as well as providing a potential bridge between theoretical and empirical studies of labile trait variation.

Opportunities and challenges of Integral Projection Models for modelling host–parasite dynamics

Epidemiological dynamics are shaped by and may in turn shape host demography. Here, Metcalf et al. extend statistically derived population models that explicitly account for variance in individual trajectories commonly used for plant and animal demography (Integral Projection Models) to capture the process of infection and propagate it across scales.

Des différences, pourquoi? Transmission, maintenance and effects of phenotypic variance

In this paper Plard et al. discuss how the influence of phenotypic variation on population dynamics is much higher in short-lived than in long-lived life-histories.

Also in the issue COMADRE: a global data base of animal demography has been published,  the paper that introduces the COMADRE Animal Matrix Database,  find out more in this blog post.

Simon Hoggart
Assistant Editor, Journal of Animal Ecology
@AnimalEcology