Estimating demographic drivers of transient population dynamics in changing environments: Towards a holistic understanding
Measuring the demographic drivers of population dynamics is fundamental for guiding conservation and management, as well as understanding eco-evolutionary processes and species interactions. The retrospective tools for doing so, however, either assume asymptotic stability of population structure in a deterministic environment or a stationary stochastic environment. Meanwhile, climate and landscape change are creating non-stationary environmental conditions (changing mean, variance, or both) for the world’s biota. To close the gap between contemporary reality and methods for measuring the demographic drivers of observed population dynamics, we develop life table response experiments (LTREs) that accommodate both transient and asymptotic dynamics in any type of time-variant environment. Given their wide applicability, we simply call these ‘time-variant’ LTREs, which can be applied to the dynamics of a single population.
Using simulations across a wide array of life histories, we explore patterns in bias produced by traditional LTREs and use our new time-variant LTREs to provide a looking glass into the types of life histories and environmental conditions for which empirical data may need to be reanalyzed. Our time-variant LTREs can be used to better understand how wild plant and animal populations cope with, buffer, take advantage of, or suffer from anthropogenic disturbances.