SppBonus: On fire and synchronous flowering

Dear Flog,

Last time I mentioned in passing that Stuart, Amy, Scott, and I had been discussing papers about fire and its potential impact on the reproductive fitness on Echinacea plants. This week I will go into greater detail about what I’ve learned about fire and what our data can teach us about how it impacts prairie health.

Some of our studies taken from previous years have shown us that, even when there are enough bees to carry pollen from plant to plant, Echinacea plants can have difficulties receiving pollen from potential mates. There are a few reasons for this. In our fragmented prairie remnants, Echinacea plants are often far enough apart that pollen collected by a bee will often fall off before it can reach another Echinacea flower. Echinacea plants may also flower in different years, or at different times in the season. This can prevent mating even between close flowers. This mate availability problem is compounded by the fact that Echinacea is self-incompatible, meaning a plant cannot pollinate itself or its close relatives. This means that if a plant flowers and fails to find mates, all the energy it expends to flower and fruit results in no offspring. This is an extraordinary energy cost for no payoff.

Data we have collected seems to suggest that fires may help perennial prairie plants like Echinacea find other mates. Explosive flowering after a large burn is typical for prairie plants. There is some evidence that increased availability of nutrients from burned organic matter and the increased availability of sunlight provide resources for a plant to invest in a costly reproductive structure like a flower. This is probably no different for Echinacea. However, as an added bonus, some of our data seems to show that this explosive flowering may reduce the reproductive isolation of Echinacea plants by increasing the number of synchronous flowering plants. Thus, fire helps Echinacea successfully seed by increasing the number of available mates. Really cool!

The tendency of Echinacea to flower synchronously after a fire could be the result of natural selection, or simply a byproduct of the excellent growing conditions created by fire. In either case, this knowledge affirms how important fires are to prairie ecosystems. The Echinacea Project, through projects like SppBonus, hopes to further elucidate these mechanisms through which fire improves prairie health.

Until next time!




Wagenius, S. and Lyon, S. P. (2010), Reproduction of Echinacea angustifolia in fragmented prairie is pollen-limited but not pollinator-limited. Ecology, 91: 733–742. doi:10.1890/08-1375.1

Ison, J.L., S. Wagenius, D. Reitz., M.V. Ashley. 2014. Mating between Echinacea angustifolia (Asteraceae) individuals increases with their flowering synchrony and spatial proximity. American Journal of Botany 101: 180-189.


August 24 – Skeleton Crew

Today when we arrived at the Hjelm house it was only 50 degrees! Brrrrrr! We were also down to a team of six following Ben’s last day on Friday and Stuart and Gretel heading back to Illinois over the weekend. (Abby was gone for her senior pictures). With so few people we got off to a quick start, because we knew we would need all the time we could get to get as much done with fewer crew members.

Our skeleton crew headed out to p2 to continue measuring that we started last Thursday. It was slow going but, having gotten through the thickest of the flowering plants on Thursday it was faster than it could have been. It is always windy at p2 since it is on top of a hill but today was especially windy and cold, most crew members could barely feel their hands which made entering data on the visor a challenge. We managed to get by, completing 20 rows before heading in for lunch.

After a warm up with some hot chocolate at lunch we headed out to do various things in the afternoon. Danny, Amy, Gina and I went to harvest heads in the remnants based on a sampling method that Danny and Amy developed. Ali and Katherine rechecked some funky measurements in p1 and harvested a few of the heads that will be used in the q3 experiment (exciting!).  Amy and I went to a ton of different remnants and encountered a few problems, like at Stevens approach were most of the heads were mowed. The highlight of our afternoon was at Aanenson where we met a really friendly cow named Willow! she came up to the fence and let us pet her. Her not-so-outgoing friends were hesitant and we didn’t pet them. Willow even gave Amy’s hand a lick, “it felt really weird” said Amy shortly after the licking. Sadly we could not spend all afternoon with our new friend and went to continue harvesting.

Willow the cow investigates her new, soon-to-be friends, Will and Amy


Willow’s friends investigate us from afar, clearly not as outgoing or cool as Willow.

July 23: Phenology and Cross-pollinating

The days and weeks are starting to fly by as we get into the busy part of the summer. Nearing the end of July, it seems like we’re hovering right around the peak of the flowering season for Echinacea angustifolia. In addition to keeping up with the phenology for our flowers (roughly a couple thousand across our remnants alone!), we’re also making timely progress on independent projects and getting important work done on the q3 experiment.

We got off to a quick start this morning sending half the crew out to do phenology at a handful of sites while Danny and Amy continued their work assessing compatibility across remnant flowers and still a few others collected pollen at Staffanson for q3. While phenology is proving to be quite the time commitment right now, we’re slowly (and satisfyingly) starting to be able to check the “Done flowering” box for more and more of our flowers. The flowering season is tapering off much faster than I had expected!

A cross-pollinator's eye view of a well-organized team carrying out crosses in p1.

A cross-pollinator’s eye view of a well-organized team carrying out crosses in p1.

The bright and breezy afternoon had most of the team out in p1 doing pollen crosses for q3. Stuart debuted a new system for keeping us organized in the field as we share, swap, switch, and track down the right vials of sire pollen to be applied to the p1 dams. While the fits of wind that persisted for much of the afternoon were a nice way to cool down, it was not very much appreciated when the breeze swept away the valuable bits of pollen we were trying to apply to our flowers!

The day ended with a visit from some of the parents of the crew members and local science teachers (these two groups actually had quite a bit of overlap). These visits were timed excellently for our guests to appreciate the Echinacea in all their peak flowering glory.

Bagged and painted Echinacea ready to be cross-pollinated.

Bagged and painted Echinacea ready to be cross-pollinated.

Happy Friday!

My beautiful bracts!

My beautiful bracts!

Ben, Gina, & Matt practice  precise painting

Ben, Gina, & Matt practice precise painting

Today was another successful day with the team! We had a morning filled with phenology at half of the sites and later everyone divided to get many things accomplished. After lunch, some of us practiced painting the bracts of Echinacea; this wasn’t too hard, it was actually very pleasant. Using toothpicks, we had to be sure to paint the tops of bracts as well as the bottom while making sure not to get paint on the florets or apply too much.

Two heads are weirder than one

I see absolutely nothing wrong here.

Here, Lea and I were at p2 collecting phenology data in the afternoon. There are 80 rows in this plot and it took us almost the whole day to get the job done! I’m from the south and it honestly takes a lot for me to confess that a place is hot, but the way the sun was blazing today, I wasn’t sure if I’d make it out of the prairie to deliver this flog post to you! It was so “warm” today I was seeing double headed Echinacea…….. sheesh.

To conclude a week full of accomplishments, Stuart sliced up the best watermelon ever. One shouldn’t argue this watermelon’s caliber; I know this was the best watermelon ever because it replenished all the sense I lost in p2 today. I’d say that everyone else enjoyed this glorious melon as well! Today was a good Friday!

Watermelon after work!

Watermelon after work!

Peak Week: The Beginning

Today marked the first weekday of the peak week of flowering for Echinacea. We are working on phenology at all the remnants as will as P1. Several flowers are already on their last day of flowering. Despite the cold and blustery conditions of today the team did crosses for the compatibility project at Loeffler’s Corner and set up the project at East Elk Lake Road. Cam and I worked on my exhaustive crossing project at Yellow Orchid Hill. We weren’t able to collect pollen and cross until after lunch, but fortunately the pollen was not blown away by the wind! Tomorrow will be more phenology and compatibility!

A Big Day for Phenology, a Great Start for Compatibility

Today was a big day for remnant phenology surveys–possibly our biggest of the season. We made the process more efficient by not recording style persistence on flowers on their 3rd, 6th, 7th, and 8th days of flowering.

But we didn’t stop there. We also collected pollen, painted bracts, and performed the first crosses with the 10 focal plants at Riley. Each focal plant was crossed with its nearest neighbor, its farthest neighbor within the remnant, the earliest flowering plant, and the latest flowering plant. This is to help us understand how compatibility varies across space and flowering time.

In other news, Will and I saw an immature bald eagle amongst the gulls and turkey vultures at the landfill.

Dividing remnants, conquering the county

Having mutually pledged to the Echinacea Project our Lives, our Fortunes and our sacred Honor, we set out this fine Saturday morning to survey the flowering phenology of Echinacea in the prairie remnants. We are interested in phenology (the study of recurring phenomena) because just as distance can genetically isolate fragmented populations, so can time. Since Echinacea cannot reproduce with itself, it needs to be flowering at the same time as a compatible mate if it wants a chance to reproduce.

To quantify flowering phenology, we have to check on the flowers every few days. Echinacea is just beginning to flower now, and we don’t want to miss anything. Today we split up into two-person teams, went to different remnants, and recorded the progress of every flowering Echinacea. All our work locating and flagging plants earlier this week allowed us to move efficiently through the sites, finishing our survey by mid-day. Here we are converging at the final site:


A formidable crew undertaking a daunting task in pursuit of a noble goal: what a glorious Saturday!

Sarah’s presentation

Sarah Baker presented “Flowering phenology of Echinacea angustifolia in Minnesota tallgrass prairie remnants over three years,” the results of her summer 2013 REU project, at the National Conference on Undergraduate Research, University of Kentucky, on 4 April 2014.
Here’s the presentation…


2011 Flowering Phenology Data

Final consolidated file of ech. ang. flowering phenology data from 2011
Edit: now with sppe and sppw differentiated

Sarah Baker 2013 Flowering Phenology Data Set

Flowering phenology data from summer 2013. This version contains data collected from 7 July, 2013 to 26 August, 2013. PhenDataMASTERcsv_28-Aug-2013.csv