Extreme weather event impacts on the spatial and temporal phenological synchrony of plants and pollinators

Background/Question/Methods  Climate change has already left a strong footprint in the timing of seasons. The Earth's seasons have shifted back in the calendar year, with spring occurring almost one week earlier in average. In consequence, the activity of plants and animals is tracking those changes. While the scientific focus of the implications of those changes has centred in a potential mismatching in phenology among different trophic levels, there has been little research on direct fitness costs of climate change for the species implicated. In this talk I revise evidence showing that despite generalist plants and its pollinators have advanced its phenology due to climate warming, they are doing so at similar paces. However, this do not imply plant-pollinator communities are robust to climate warming. To exemplify this, I use a survey of plant-pollinator interactions across 16 mediterranean open forests patches conducted along three consecutive years to show the impacts of extreme weather years like the dry and warm 2016.

Results/Conclusions First, I show that the phenology of both plants and pollinators was advanced by six weeks in 2016 in comparison with normal years. This implies an unprecedented advance in plant flowering which in 2006 started in the middle of winter (14 January). Interestingly, although plant-pollinator synchrony was mostly maintained, plant reproduction success and pollinator abundance were lower than in reference years. Second, I show that the spatial variability in phenology across different forest patches increases in extreme weather years, indicating the importance of microclimatic conditions to buffer the consequences of extreme weather years. The frequency of extreme hot years is increasing in the last decade, and the long term implications for the ecosystem need urgent attention.