The limits of demographic buffering in coping with environmental variation

Animal populations have developed multiple strategies to deal with environmental change. Among them, the demographic buffering strategy consists in constraining temporal variation of vital rate(s) that most affect(s) overall performance population. Tortoises are known buffer their adult survival, which typically has highest contribution population growth rate ?, at expense a high variability on reproductive rates, contribute far less ?. To identify effects projected increases droughts its natural habitat, we use field data collected across 15 locations Testudo graeca southeast Spain over decade. We analyse variables reproduction rates. In addition, couple and parameterise an integral projection model simulate different scenarios drought recurrence ? under degrees intensity survival–reproduction tradeoff. find negatively affect probability laying eggs; however, current (one/decade) negligible when survival is constant (independent reduction by events) increased as tradeoff threshold viability three or more droughts/decade. Additionally, show that, although some species may regimes carefully orchestrating how rates vary through time, insufficient ensure extreme regimes. Our findings support hypothesis limit effectiveness adverse conditions occur frequently. methodological approach provides framework for ecologists determine effective management drivers can be demographically populations, not provide long-term persistence.