Climate change increases mean global temperatures, interannual variability and frequency of extreme climatic events. It applies a directional and fluctuating selection on natural populations. In this context, my researches aim at identifying factors facilitating adaptation of natural populations to climate change. During my PhD I investigate how reproductive regimes and particularly assortative mating (mating between similar individuals) for phenological traits may facilitate adaptation to climate change. My research also deals with the effects of yearly variation of selection intensity on adaptive responses. I use a theoretical approach combining individual-based simulations and analytical models of quantitative genetics to resolve these issues. Conditions favoring the maintenance of higher genetic variance and the track of climate change by populations are identified by comparing different scenarios.