A Trade-Off between Robustness to Environmental Fluctuations and Speed of Evolution

Abstract

Organisms must cope with both short-and long-term environmental changes to persist.In this study we investigated whether life histories trade-off between their robustness to short-term environmental perturbations and their ability to evolve directional trait changes. We could confirm the tradeoff by modeling the eco-evolutionary dynamics of lifehistories along the fast-slow pace-of-life continuum. Offspring dormancy and high adult survival rates allowed for large population sizes to be maintained in face of interannual environmental fluctuations but limited the speed of trait evolution with ongoing environmental change. In contrast, precocious offspring maturation and short-living adults promoted evolvability while lowering demographic robustness. This tradeoff had immediate consequences on extinction dynamics in variable environments. High evolvability allowed short-lived species to cope with long-lasting gradual environmental change, but came at the expense of more pronounced population declines and extinction rates from environmental variability. Higher robustness of slow life-histories helped them persist better on short timescales.

Demographic feedbacks during evolutionary rescue can slow or speed adaptive evolution

“…The principles determining the potential for evolutionary rescue discussed here are relevant to the evolution of resistance to treatments in infectious disease and cancer [6]. In fact, the idea that maladaptation via lower birth rates versus higher death rates may provoke different adaptive responses has been noted in these fields, though typically with a focus on mutational input per unit time [23,41]. For example, Igler et al [70] model the evolution of resistance to bacteriocidal versus bacteriostatic antibiotics, noting that bacteriocidal antibiotics can lead to greater mutational input under some conditions.…”

“…While the effect of generation time on the rate of evolution may be simple to predict, how generation time itself emerges from the complex interactions among rates of growth, birth, and death across ages or stages is less so. These interactions make it difficult to isolate the effects of generation time on evolutionary rescue from other, correlated factors like resilience to shortterm environmental fluctuations [23]. For example, higher adult mortality rates can speed up the response to selection by increasing turnover [24][25][26][27][28][29], but may come with relevant downsides like a decrease in population size.…”

A demo‐genetic model shows how silviculture reduces natural density‐dependent selection in tree populations

“…Extending the model to disturbance regimes with additional specific resistance traits independent from the target of density‐dependent selection would be an approach to investigate the trade‐off between resistance to disturbance and long‐term adaptation in long‐lived organisms (Schmid et al., 2022). Drawing evolutionary expectations in uneven‐aged forest systems is much more challenging because they combine specific mechanisms of asymmetrical competition, overlapping generations, and highly unbalanced male and female fecundities, which all have an effect on genetic drift and selection.…”

Microdiverse bacterial clades prevail across Antarctic wetlands

“…More specifically, the heavily restricted dispersal imposed by the snow‐covered CPWC landscape appears to facilitate the microdiversification processes (Nemergut et al., 2013; Stegen et al., 2013; Zhou & Ning, 2017). We also hypothesize that microdiverse bacterial clades thriving in this system have phylogenetically conserved traits that accelerate their rate of evolution, enabling them to rapidly adapt to strong and spatio‐temporally variable selection pressures within the CPWC environments, resembling trade‐offs related to trait evolutionary responses (Schmid et al., 2022). Nevertheless, as variation in highly conserved marker genes (e.g.…”