The diversity of population responses to environmental change

Abstract

The current extinction and climate change crises pressure us to predict population dynamics with ever‐greater accuracy. Although predictions rest on the well‐advanced theory of age‐structured populations, two key issues remain poorly explored. Specifically, how the age‐dependency in demographic rates and the year‐to‐year interactions between survival and fecundity affect stochastic population growth rates. We use inference, simulations and mathematical derivations to explore how environmental perturbations determine population growth rates for populations with different age‐specific demographic rates and when ages are reduced to stages. We find that stage‐ vs. age‐based models can produce markedly divergent stochastic population growth rates. The differences are most pronounced when there are survival‐fecundity‐trade‐offs, which reduce the variance in the population growth rate. Finally, the expected value and variance of the stochastic growth rates of populations with different age‐specific demographic rates can diverge to the extent that, while some populations may thrive, others will inevitably go extinct.

Population position along the fast–slow life‐history continuum predicts intraspecific variation in actuarial senescence

“…unknown death date) capture–recapture data in our analysis. Our analyses focus on the post‐metamorphic stage at which senescence is expected to occur (as in Colchero et al, ). B a STA allows estimation of two parameters: age‐dependent survival and the proportion of individuals dying at a given age (i.e.…”

“…As the study period and number of survey years differ among populations (Appendix S1), the four populations were analysed separately. We used the deviance information criterion (DIC) to select models that fitted the data best (Colchero et al, ) and we compared the outputs of the best‐supported model of the four populations by inspecting mean estimates and 95% credible intervals (CRI; Amrhein, Greenland, & McShane, ; Anderson, Link, Johnson, & Burnham, ). This allowed us to investigate population‐specific variation in the shape of the age‐specific mortality patterns.…”

“…First, actuarial senescence is a nearly ubiquitous process in the living world (Nussey, Froy, Lemaitre, Gaillard, & Austad, ; Shefferson, Jones, & Salguero‐Gómez, ). Second, patterns of senescence can be highly variable among species (Colchero et al, ; Jones et al, ; Tidière et al, ). Comparative analyses have shown that senescence patterns across multicellular organisms can be predicted by ecological traits, lifestyles and covariation among life‐history traits (Gaillard et al, ; Péron, Gimenez, Charmantier, Gaillard, & Crochet, ; Ricklefs, ; Salguero‐Gómez & Jones, ).…”

Changing patterns of growth in a changing planet: How a shift in phenology affects critical life‐history traits in annual fishes

“…While climate change can alter the ecology of many species (Walther et al., ), potentially driving some towards extinction (Thomas et al., ), we show that A. bellottii appears able to cope with sporadic shifts in rainfall patterns. This finding indicates that environmentally triggered phenotypic plasticity of life‐history traits expressed by A. bellottii can maintain viable populations despite altered phenology (Colchero et al., ). In fact, A. bellottii has a relatively wide distribution and some populations reach the Río Paraguay basin in northern Argentina (García et al., ) where precipitation seasonality is different to the study region and fish hatch when the water temperature is warmer.…”

“…The primary effects of climate change are alterations in precipitation and temperature dynamics, which have profound implications for species’ phenologies (Ficetola & Maiorano, ; Parmesan, ). However, responses to climate change and its consequences potentially vary among species (Both, Van Asch, Bijlsma, Van Den Burg, & Visser, ; Colchero et al., ) and particular interspecific interactions (Gilman et al., ; Hassall et al., ). The changes associated with late hatching that we observed demonstrated the capacity of A. bellottii to cope with a shift in seasonality and to adjust their life history to maximise reproductive success.…”