Local adaptation of annual weed populations to habitats differing in disturbance regime

Plants have evolved several strategies to cope with disturbance, and one strategy is tolerance. In tolerance, plants store resources (meristems, carbohydrates) so that they can resprout after disturbance and thereby compensate to some degree for losses. Because tolerance is costly (it occurs at the expense of current growth), we can expect adaptation to the local disturbance regime. In this study, we determined whether populations of a common European annual weed, Euphorbia peplus, are adapted to the local disturbance regime. We hypothesized that the tolerance and hence compensation for losses in seed and biomass production after experimental damage are greater in plants from more severely disturbed than from less severely disturbed populations. We also hypothesized that transgenerational effects can alter adaptation. We found that compensation for biomass loss to damage was greater for plants from more severely disturbed habitats than for plants from less severely disturbed habitats. This, however, was not at the expense of growth before damage because plants from both disturbance regimes did not show differences when not damaged. Transgenerational effects played a positive role in adaptation to disturbance during germination and maturity. We conclude that local adaptation together with transgenerational effects have evolved in more severely disturbed populations but not in less severely disturbed populations of E. peplus.