Climate and Wildflowers: Leavenworthia Study Sheds Light on Roles of Climate Change and Conservation

    By Kathleen Berger, Executive Producer for Science and Technology

     Wildflowers are noticeably rooted in our environment, as they are easily seen by their colors and beauty. They are more than spring and summer décor. They are the calm and quiet participants in the ecosystem.

    Flowers provide food and habitat for pollinators and birds. Flowering plants help make our landscapes more sustainable. They bloom and thrive when the climate is right, which is why climate change is a concern worth studying.

    “It’s important to understand the effects of climate change on flowering, both for the conservation of flowering plant species and also for the preservation of biodiversity,” said Matthew Austin, Postdoctoral Research Fellow with the Living Earth Collaborative at Washington University in St. Louis.

    Austin is working in collaboration with the Missouri Botanical Garden.

    “My area of research is exploring how climate change affects how plants survive and reproduce,” he said.

    Austin works closely with the experts at Missouri Botanical Garden at Shaw Nature Reserve. He has conducted experiments at Shaw Nature Reserve with different flowers over the years.

    “This research is important beyond just the enjoyment of flowers because understanding what affects the time of year that plants reproduce is important for their conservation.”

    Recently, his lab focused on Leavenworthia flowers that blooms in early spring.

    “Leavenworthia comprises eight species and half of those species, four out of eight, are imperiled or critically imperiled and one is threatened to such a degree that it’s listed on the U.S. Endangered Species Act. It’s important for Leavenworthia to occur early in the spring before species that occur later in the year emerge and could be potential competitors with Leavenworthia in environments with many competitors,” Austin explained. “There can be fitness disadvantages to species in terms of not being able to attract as many pollinators as they would if they were blooming in environments with fewer other species present. Thus, it is highly important, for the conservation of this threatened group of plants, to study how climate change is affecting the time of year that their reproduction occurs.”

    Austin’s student and lab assistant Kelsey Bartlett is the lead author of the Leavenworthia study.

    “The two main questions we wanted to answer – is Leavenworthia phenology, which is flowering or fruiting time, changed over time, over the 117 years that our records span? And if so, how? And then second, we were curious about what factors had the biggest influence on flowering and fruiting time,” Bartlett said.

    Bartlett’s research involved data analysis, with records collected across several states including records from Shaw Nature Reserve in Missouri.

    “Pretty much consisted of looking at this giant spreadsheet of 900 different records that we compiled from these different sources. Most of the species occur in the Central Basin of Tennessee. However, there is a much more widespread species of Leavenworthia uniflora that occurs west of the Mississippi. We used a statistical process called variance partitioning, did a lot of fun code,” she said. “And what we found was that Leavenworthia flowering time has advanced by about two days per decade and fruiting time has advanced by about 1.3 days per decade.”

    The research team then used the data to examine the role of climate change to discover warmer and drier springs is a major contributor to Leavenworthia blooming earlier.

    “We were surprised by the findings of this study. In particular, we predicted that the non-climatic factors that we looked at such as latitude, which is a proxy for day length, would have a much larger role,” said Austin. “Rather, we were surprised that climatic factors, in particular spring temperature and spring precipitation, had a by far dominant influence on the time of year of Leavenworthia reproduction. Their flowering occurs earlier in warmer and drier springs.” ­

    Austin said the study has value for the conservation efforts of Leathenworthia and much more.

    “This research can be used to perform similar studies in species that are important for global food supply, such as many of our important crop species,” Austin explained. “It would be interesting to compare whether species that are important for the global food supply are similarly mostly affected by climate compared to non-climatic factors, as we found in Leavenworthia.”