Last week I assessed Echinacea flowering phenology at Grand River National Grassland south of Lemmon, SD, Samuel H. Ordway Prairie west of Leola, SD and Staffanson Prairie near Kensington, MN. Here are a couple of figures I generated to compare phenology at the 3 sites.
First, I made pie charts to show the relative proportions of flowering plants.
Next, to show more quantitative information, I used a stacked bar graph.
These figures illustrate that the flowering phenology is most advanced at Staffanson and least advanced at S. H. Ordway Prairie. Nevertheless, I am encouraged that there are lots of flowering plants at all 3 sites, suggesting that a long-distance cross involving plants from these 3 locations would be possible. I am considering tackling that project next summer, to assess whether there would be lower seedling recruitment from between-population crosses compared to within-population crosses at these 3 sites.
Here’s a picture of some flowering Echinacea at Perch Lake, which is near the S. H. Ordway prairie.
We are very interesting in observing (and participating in) the Echinacea mating season this summer. We are still waiting for the action to begin.
Here is a map of the flowering plants in the main garden. Each dot represents a plant with 1 or more buds (immature capitula). The short purple bar indicates a plant with one bud, a long bar indicates two, and n short bars indicates n buds. In the main garden we found 869 plants with at least one bud and a total of 1572 buds. The most buds on a plant is 11. This is a modified “sunflower plot” that was generated with R.
We are waiting for the action to begin. At this time last year, like most years, Echinacea flowering was in full swing.
We are prepared for the flowering to begin. We flagged all positions evenly divisible by 5. We mowed paths between rows so we can avoid stepping on plants. We have flagged every flowering plant. Note: don’t buy fluorescent colored pin flags. The flags tend to detach from the more frequently than non-fluorescent colors. What’s up, Forestry Suppliers? We weeded thistles and sweet clover, trapped gophers, found plants with Aster yellows, and are waiting for the action to begin.
This flog entry from last year proved valuable. I just looked it up and followed the common garden maintenance protocol.
As I’m preparing to write updates on experiments for 2024, it was brought to my attention that we don’t have one post summarizing all our updates from summer 2023! So, while you eagerly await this year’s news, enjoy a refreshing blast from the past. Here’s what we did last summer!
Members of Team Echinacea 2023 measure plants in our hybrid experimental plots at Hegg Lake WMA
Small remnant Echinacea populations may suffer from inbreeding depression. To assess whether gene flow (in the form of pollen) from another population could “rescue” these populations from inbreeding depression, we hand-pollinated Echinacea from six different prairie remnants with pollen from a large prairie remnant (Staffanson Prairie) and from a relatively small population (Northwest Landfill) in 2008. We also performed within-population crosses as a control. Amy Dykstra (with help from Caroline Ridley) planted the achenes (seeds) that resulted from these crosses in an experimental plot at Hegg Lake WMA.
We sowed a total of 15,491 achenes in 2008. 449 of these achenes germinated and emerged as seedlings. Each summer, we census the surviving plants and measure them.
In the 2023 census, Amy found 23 surviving basal plants and no flowering plants. She had observed 26 basal plants in 2022. Mortality was high during the first four years, but has been lower as the surviving plants have increased in age.
Number of plants observed in annual censuses 2008-2023
Data collected: Plant fitness measurements (plant status, number of rosettes, number of leaves, and length of longest leaf), and notes about herbivory. Contact Amy Dykstra to access this data.
Samples or specimens collected: NA
Products: Dykstra, A. B. 2013. Seedling recruitment in fragmented populations of Echinacea angustifolia. Ph.D. Dissertation. University of Minnesota. PDF
You can read more about Dykstra’s interpopulation crosses, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.
In summer 2023, Amy continued the interremnant crosses experiment to understand how the distance between plants in space and their timing of flowering influences the fitness of their offspring. This experiment builds on her study of gene flow and pollen movement in the remnants, asking the question of how pollen movement patterns affect offspring establishment and fitness. If plants that are located close together or flower at the same time are closely related, their offspring might be more closely related and inbred, and have lower fitness than plants that are far apart and/or flower more asynchronously. In other words, if distance in space or time is correlated with relatedness, we’d expect mating between more distant or asynchronous individuals to result in more fit offspring.
To test this hypothesis, Amy performed crosses between plants across a range of spatial isolation (within the same population, in adjacent populations, and in far-apart populations) in 2020. With the team’s help, she also kept track of the individuals’ flowering time to assess whether reproductive synchrony is associated with reduced offspring fitness, suggesting that individuals that flower at the same time are more closely related.
In 2021, Amy repeated the same hand crossing methods to assess the fitness consequences of outcrossing, this year on 44 focal plants.
In spring 2022, she planted the seedlings as plugs into exPt01 and measured the seedlings throughout the summer. Amy measured plants again in summer 2023!
Amy’s two batches of plants (that were alive this year) were assigned cg plaids and are now integrated in the p01 workflow. They are named as integers from 29001 – 29319 and are referred to as “Amy’s Annex”.
A young Echinacea Plant in Amy’s Annex
Start year: 2020
Location: On27, SGC, GC, NGC, EELR, KJ, NNWLF, NWLF, LF
Data collected: Style shriveling and seed set and weight from crosses, start and end date of flowering, coordinates of all individuals in the populations listed above. Leaf count and height of seedlings at three points during the summer (two weeks after planting, mid-summer, and late summer). Summer 2023 measure data can be found here: “~/Dropbox/CGData/125_measure/measure2023/measure2023_out”
Samples or specimens collected: NA
Products: Amy wrote up a related analysis using parentage data from P2 to look at interparent distance and asynchrony in relation to offspring fitness. That manuscript is in prep now.
You can read more about the interremnant crosses experiment here.
In spring 2023 we planted about 100 Asclepias viridiflora seedlings in plugs to transects at site eth. The planting data sheets with all details are in Jared’s office. We did not monitor these seedlings after planting.
During summer 2023, we collected demographic data on 172 individual Asclepias viridiflora plants across 17 sites. We also collected 52 seed pods from 26 maternal plants.
A very charismatic cryptid
Dathon Maton and Mary Ashley at the University of Illinois at Chicago have made great progress genotyping tissue collected from seedlings and potential parents in remnant populations. These genetic data coupled with our spatial and demographic data will help us understand the genetic structure of milkweed populations and patterns of gene flow within and among remnants.
Start year: 2021
Location: 17 patches of remnant tallgrass prairie near Solem Township, MN
Data collected: Spatial and demographic data have been curated and are housed within the remav repo. Harvested pods have been cleaned, counted, and x-rayed but need to be classified.
Samples or specimens collected: 2023 harvested seeds are in Jared’s office. Previous year’s seeds were returned to remnant populations.
Products: Stay tuned!
You can read more about the Asclepias viridiflora demography experiment, as well as links to prior flog entries about this experiment, on the background page for this experiment.
Small remnant Echinacea populations may suffer from inbreeding depression. To assess whether gene flow (in the form of pollen) from another population could “rescue” these populations from inbreeding depression, we hand-pollinated Echinacea from six different prairie remnants with pollen from a large prairie remnant (Staffanson Prairie) and from a relatively small population (Northwest Landfill) in 2008. We also performed within-population crosses as a control. Amy Dykstra (with help from Caroline Ridley) planted the achenes (seeds) that resulted from these crosses in an experimental plot at Hegg Lake WMA.
We sowed a total of 15,491 achenes in 2008. 449 of these achenes germinated and emerged as seedlings. Each summer, we census the surviving plants and measure them.
In 2022, we found 26 surviving plants; all were basal. Joey McGarry staked the plant locations, Amy Dykstra searched for the plants, and Brad Dykstra recorded the data.
Data collected: Plant fitness measurements (plant status, number of rosettes, number of leaves, and length of longest leaf), and notes about herbivory. Contact Amy Dykstra to access this data.
Samples collected: NA
Products: Dykstra, A. B. 2013. Seedling recruitment in fragmented populations of Echinacea angustifolia. Ph.D. Dissertation. University of Minnesota. PDF
You can read more about Dykstra’s interpopulation crosses, as well as links to prior flog entries mentioning the experiment, on the background page for this experiment.
In summer 2022, I continued the interremnant crosses experiment to understand how the distance between plants in space and their timing of flowering influences the fitness of their offspring. This experiment builds on my study of gene flow and pollen movement in the remnants, asking the question of how pollen movement patterns affect offspring establishment and fitness. If plants that are located close together or flower at the same time are closely related, their offspring might be more closely related and inbred, and have lower fitness than plants that are far apart and/or flower more asynchronously. In other words, if distance in space or time is correlated with relatedness, we’d expect mating between more distant or asynchronous individuals to result in more fit offspring.
To test this hypothesis, I performed crosses between plants across a range of spatial isolation (within the same population, in adjacent populations, and in far-apart populations) in 2020. With the team’s help, I also kept track of the individuals’ flowering time to assess whether reproductive synchrony is associated with reduced offspring fitness, suggesting that individuals that flower at the same time are more closely related.
In 2021, I repeated the same hand crossing methods to assess the fitness consequences of outcrossing on 44 focal plants. However, instead of planting the offspring from these crosses as seeds, I germinated them in the growth chamber and transferred sprouts to a plug tray.
In spring 2022, with help from the team, I planted the seedlings as plugs into ExPt1. I measured the seedlings throughout the summer.
Lindsey digs a hole for an Echinacea plugA baby Echinacea!Amy plants Echinacea in ExPt1 after the burn
To learn more about Amy’s project, check out this video created by 2021 RET participant Alex Wicker.
Start year: 2020
Location: On27, SGC, GC, NGC, EELR, KJ, NNWLF, NWLF, LF
Data collected: Style shriveling and seed set and weight from crosses, start and end date of flowering, coordinates of all individuals in the populations listed above. Leaf count and height of seedlings at three points during the summer (two weeks after planting, mid-summer, and late summer).
On Friday, grad student Amy W. paid a visit to the lab at the Chicago Botanic Garden to x-ray Echinacea achenes for several of her projects including the Dust Project, interremnant crosses, and gene flow experiments. We’re thrilled to have a functional x-ray machine once again. Amy noticed lots of variation in her samples, so we’re excited to learn about seed set for these experiments!
