In a nutshell
Around the globe, the timing of seasonal activity in plants and animals is changing in response to warming temperatures. Most scientific studies of these timing shifts have been based on observations collected at a handful of sites on a small number of species. Limited data availability has challenged efforts to assess whether these smaller studies “scale up” and reflect patterns over large geographic areas and for many species.
The abundant observations contributed to Nature’s Notebook now make it possible to answer these questions. A team of researchers used thousands of Nature’s Notebook observations to see whether plants in the eastern U.S. leafed out or flowered earlier with warmer temperatures. They evaluated whether responses differed among species or across latitude. They also compared data from Nature’s Notebook with data collected by professional scientists at sites run by the National Ecological Observatory Network (NEON).
They found that Nature’s Notebook observations and NEON observations produced very similar results. For most species, warming temperatures resulted in earlier leaf-out and earlier flowering. Invasive species were more sensitive to warming temperatures than native species, and shrubs were more sensitive than trees or forbs. They also found that plants in the south were more sensitive to warming temperatures than plants in the north. In response to temperature increases, plants in the south are advancing the timing of their activity to a greater degree. In general, the patterns they observed were similar to results from small-scale studies, providing more evidence that warming temperatures will have a significant effect on plant communities throughout the U.S.
What is special about this study?
Our understanding of climate change impacts is usually based on studies of few species in a limited area. Here, the authors used observations of many plant species from across the eastern U.S. to identify large-scale patterns. They found that observations collected by volunteers were just as robust as data collected by professionals and can provide information about species and regions that haven’t traditionally been a part of scientific studies.
What does this mean for YOU?
This analysis would not have been possible without thousands of observers like you contributing data to Nature’s Notebook. This impressive dataset provided strong evidence that warming temperatures are causing leaf-out and flowering to occur earlier in many plant species. Continued monitoring will help document these changes, but keep in mind that you may need to go out a bit earlier in the year to observe these important spring events!
Citation: Gallinat, A.A., M.D. Schwartz, A. Donnelly, X. Li, and T.M. Crimmins. 2025. Combined volunteer and ecological network observations show broad-scale temperature-sensitivity patterns for deciduous plant flowering and leaf-out times across the eastern USA. Journal of Ecology. https://doi.org/10.1111/1365-2745.70165