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Missouri Botanical Gardens

Let there be rain! – It seems like every year there are more reports of longer or more severe droughts around the world. And, unfortunately, this trend is expected to continue as climate change intensifies. Much of the media coverage about droughts is focused on the effects on agriculture, but it is important to remember that these droughts are affecting natural systems too, including populations of rare plants. Recently, researchers from a CPC member institution, the Missouri Botanical Garden, and Washington University in Saint Louis teamed up to see if they could improve the management of a rare, federally endangered plant (Astragalus bibullatus) in the face of worsening drought. Their research suggests that yes, we can! But, it isn’t going to be easy. . .

Arboretum at Flagstaff

Common garden studies, where plants taken from different populations are grown in the same environment, have been carried out for decades by agencies like the United States Forest Service. These simple experimental designs allow the researcher to identify traits in the plant that are genetic-based by keeping all the environmental variables “common”. The Arboretum at Flagstaff, in partnership with Northern Arizona University, is host to an exciting new research instrument known as SEGA or the Southwest Experimental Garden Array, that uses common garden sites. Funded by the National Science Foundation, this research tool enables scientists to examine questions addressing climate change, genetics, plant responses and so much more by using elevation as a proxy for different climates. SEGA is composed of 10 common garden sites, two of which are located at The Arboretum, spread across northern Arizona.

Denver Botanic Gardens

Phenology is the study of how climate affects things like bird migrations or plant flowering. It is also one of the best ways to observe how plants respond to climate change, and to predict future changes in plant communities. According to the researchers at Denver Botanic Gardens, phenological studies with respect to climate change could be improved if herbarium specimens were combined with monitoring efforts over longer periods. The researchers analyzed herbarium specimen data from Colorado’s alpine region (as alpine areas are predicted to be especially sensitive to climate change). They then assessed phenological patterns in relation to temperature and precipitation for 385 species and Growing Degree Days (GDD) for 311 species. Average low temperature, maximum GDD, and average precipitation increased over the study period. As temperature and GDD increased, their effects on specimens happened sooner, but as precipitation increased, the effects were delayed. Even with this variability, a significant trend of earlier flowering appeared when all species were analyzed together. Of the species that showed significantly earlier flowering dates, they advanced on average more than 32 days over the 61 years of the study. When assessing only specimens of species monitored in a national program (USA National Phenology Network), they found that these species showed similar trends to all of the study specimens. When selecting species for ongoing monitoring efforts, herbarium specimens are an important resource to incorporate historical patterns into assessments of climate change and phenological drivers. (Credit: Under-review manuscript abstract – provided by Denver Botanic Gardens; photo@Scott Dressel-Martin)

Learn more about Phenology, and phenological research at the Denver Botanic Gardens, here. They have also developed a Phenology Trail in Colorado, which consists of Phenology Walks – “These Walks provide the participant with places to visit, enjoy nature, collect date, and learn about supporting organizations.”