As we reach peak summer in southern Maine, it is hard not to think about climate change with every day that hits 90+ degrees. In addition to the heat, there are other extreme conditions that are being exacerbated by climate change. Although our native plants are adapted to a range of regional conditions, hitting those extremes can stress plants and decrease survival. And what about invasive species—how will they fare compared to our native plants?
A recent study published this June explores how varied climate change factors can stack up and interact to decrease plant survival between native and invasive plants (Zhao et al. 2025. Global Change Biology 31(6):e70282). The authors tested 10 native Chinese species and 10 invasive species, divided in half between annuals and perennials. They explored six climate change factors: drought, salinity, microplastics, herbicide, heat wave, and eutrophication (a process which begins with excessive nutrients leading to algal blooms and oxygen depletion in estuaries and aquatic environments). As one might expect, the more factors plants had to deal with, the worse plants fared. When compounded with other effects, drought and salinity in particular made bad conditions even worse. The only exception was eutrophication—although extra nutrients can have harmful effects on their own, they seemed to mitigate some of the issues caused by other climate change factors.
In all cases, both native plants and invasive plants suffered from extreme conditions. But which performed the worst? Previous studies had found that when plants were only affected by one factor, invasive species survived better than native plants. However, in this study, when multiple factors were stacked together, native plants were a bit better adapted to deal with those extreme conditions.
Invasive annuals in particular did the worst, likely because their survival year after year depends on seedling establishment, whereas perennials rely on resources stored in their roots. The authors suggest that native plants are better at tolerating varied conditions on their home turf, whereas invasive plants can only take off under certain conditions. Regardless of how native plants and invasive plants compared to each other, both plants struggled under these extreme conditions; however, native plants may have a slight advantage when it comes to drastic changes.
Even when looking at ecotypes within an individual species, local plants can outperform other non-local plants that may be better adapted to certain conditions. One study used six native German grassland species to explore how different ecotypes reacted to a natural heat wave (Bucharova et al. 2016. Ecology and Evolution 6(12):4160-4165). The authors planted ecotypes from a region with long-term high temperatures side by side with local ecotypes. The non-local plants did not do any better than the local plants—in fact, in two of the species, local ecotypes performed better in the heat than the warm-adapted non-local plants. So in the face of climate change, let’s trust that the plants that have evolved and adapted to this region know what they’re doing. Buy local, and plant native!
