Foreseeing population collapse is an on-going target in conservation biology and ecology, and has led to the development of early warning signals based on expected changes in leading indicators prior to a bifurcation. Such signals have been sought for in abundance time-series data on a population of interest, with varying degrees of success. Here we move beyond these established methods by including parallel time-series data of abundance and fitness-related trait dynamics.
Results/Conclusions
Using experimental data we show that including information on the dynamics of phenotypic traits such as body size into composite early warning indices can produce more accurate inferences of whether a population is approaching a critical transition than using abundance-time-series alone. By including fitness-related trait information alongside traditional abundance based early warning signals in a single metric of risk, our generalizable approach provides a powerful new way to assess what populations may be on the verge of collapse.