High-resolution data is necessary to detect the effects of climate on plant population dynamics

Background/Question/Methods

Climate is assumed to strongly influence species distributions and abundances. Even though the performance of many organisms is influenced by the climate in their immediate proximity, the climate data used to model their distributions often has a coarse spatial resolution. This is problematic because the local climate might deviate substantially from the regional average, particularly for sessile organisms in areas with a complex topography and in forests where the canopy buffers temperature extremes.To explore whether the spatial resolution of climate data influences the ability to detect climate effects on population dynamics, we used climatic factors measured at two spatial resolutions and integral projection models with demographic data from 37 populations of the forest herb Lathyrus vernus across a wide latitudinal gradient during two annual transitions.

Results/Conclusions

We detected no effects of climate when using regionally-aggregated data. However, using locally-measured climate data, we found that frost and accumulated heat during spring negatively affected the population growth rate in one of two annual transitions, and that spring frost had adverse effects on survival in both transitions. Our findings show that approaches using regionally-aggregated climate data might fail to identify effects of climate on plant population dynamics. Thus, especially for sessile organisms that experience the climate locally, climate data at high spatial resolutions are necessary to identify effects on individual performance and population dynamics.