Wildflowers are blooming earlier, potentially impacting the region's wildlife
A new study from the Nature Conservancy in Wyoming found that many wildflowers and other plants in the Grand Teton-Yellowstone area are blooming and bearing fruit earlier than they did 50 years ago. Wyoming Public Radio's Kamila Kudelska asked ecologist and co-author Trevor Bloom how the study came about.
Trevor Bloom: The idea for this study definitely came from my colleague, Corinna Riginos and Corinna several years ago was working for Teton Science School. And she was teaching out of this book called, "For Everything There Is a Season: The Sequence of Natural Events in The Teton Yellowstone Area." And that book, "For Everything There Is a Season," was written by Dr. Frank Craighead and was a week-by-week account of what you'd expect to see in the Teton area.
So, say you open it up to this week, you would talk about how the Aspen's are starting to bud or they're starting to create flowers and the mountain bluebirds are returning from their migration. And when she was teaching that book, she started to realize that things were getting out of sync, they're getting out of whack. She got the idea of replicating this study, the Craighead study in the future. And basically, that's where I came in. I just finished my graduate degree in botany. And I was happy to jump in and start replicating this study.
Kamila Kudelska: So what did you do? How did you replicate the study?
TB: The first step, which was kind of fun, so we got the archives from the Craighead family. So not only do we use the book, we actually got the handwritten notes that were written by Dr. Frank Craighead from 1973 to 1978 and again in 1988. And there are these handwritten notes that were archived at his house.
He passed away several years ago, but we got the notes from his family. And we digitized the notes, we turned them into spreadsheets. And we then found about 50 species of plants that had really good records, multiple years of records, the first flowering date. And then essentially, I just retraced his footsteps starting at his old historic cabin site, which is now in Grand Teton National Park, walking through sagebrush meadow, and up towards the summit of Blacktail Butte. And along the way, I just recorded all the different flowers that I saw, and in what stage they're in. I did that for two to three days per week. So twice a week, at least, for four years. Basically, I just got to walk around and look at wildflowers.
KK: Very cool. And so what did you find out? What were the results of it?
TB: The results were a little bit staggering. We expected that certain wildflowers would be flowering earlier, as a result of warming temperatures. That was our hypothesis. But we had no idea when we started that we would find that many flowers were flowering about three weeks earlier than in the 1970s. And in some cases, plants like hooded flocks, which flowering on average 36 days earlier than first observed by Craighead. In general, we found that the spring flowers, the ones that come out in May and June are coming out about three weeks early, the mid summer flowers, plants, like lupins that come out in July, are coming out about 10 days earlier. And then late summer flowers, like goldenrod, or fireweed, are actually not coming out earlier at all.
KK: What does this mean? You know, why should people be interested in this? And how can it potentially impact our ecosystem?
TB: There's several reasons why people should be interested. You know, one is, it's just a very clear example of how climate change has already affected the sagebrush ecosystem. A lot of climate change research looks to the future…2050, 2070 we're going to live in a very different world. But this is a concrete example of how the ecosystem has changed since the 1970s. And it's a very clear story and you talk to people in Wyoming and they might not want to engage in a conversation about climate change, but they'll definitely engage in how things have changed. since they were growing up. How the growing seasons are getting longer or the streams are getting lower later in the season or the snow is melting earlier.
But in particular, the greatest effects are going to be on wildlife. One example is sage grouse, so greater sage grouse rely on early spring wildflowers and the insects that pollinate those early spring wildflowers are their primary food sources in the spring, and their nesting success is directly tied to those wildflowers. And because those plants are coming out much, much earlier than they were historically that might have implications for the survival of sage grouse.
Because coming out earlier actually isn't necessarily a good thing. It makes these plants more susceptible to early disease. Then frost and die offs. So they come out earlier because it's warmer and the snow melts, but then you still get these freezes in early April, and then all the petals fall off. And then of course those plants don't survive. So there's definitely implications for sage grouse. And we also talk about in the paper the implications for bears, because we also found berry producing shrubs, like serviceberry and chokecherry and Huckleberry. They're coming out about a week earlier. And likely, they're fruiting even more than a week earlier than they were historically, meaning food sources for bears that are very important late in the fall, when they go into hyperesthesia, a period where they're just trying to eat as much as possible, that the berries are probably coming out more like late summer instead of early fall.
And they might not actually have those food sources they need before going into hibernation, which could result in increased human-bear conflicts in general. We tend to point to the restoration implications of this is that restoration practitioners in the national parks in the National Forest and state parks should really consider in their seed mixes and what they're planting when they're trying to restore habitats, to try to have early season flowering species in those seed mixes, mid-summer flowering species and even late summer flowering species to try to get that overall diversity of flowering times and floral resources for the wildlife that depend on them.