2023 Update: Predators in prairie remnants and restorations

Ants are an integral part of ecosystems, playing a role in seed dispersal, detritus removal, pest predation, and nutrient cycling. Because ants nest in the ground, they are particularly susceptible to any process that disturbs the earth and can be heavily impacted by land use practices and management decisions. Diane Roeder, at Augustana University, designed this survey to quantify ant species diversity in remnant and restored prairie patches in western MN. These sites are primarily managed by fire, a type of disturbance that has been hypothesized to impact ant species differently via mortality and/or changes in habitat structure. During the summer, Diane and members of team Echinacea sampled 45 prairie sites (30 remnant, 15 restored), deploying a total of 415 pitfall traps. Diane and her colleagues are in the process of sorting ants from other ground-dwelling invertebrates captured by the traps and will identify specimens to compare abundance, species richness, and community composition from sites under different management regimes. In addition to measuring diversity, They also deployed sentinel prey items to determine whether arthropod communities in these areas remove prey at different rates as a measure of ecosystem services provided by predatory arthropods. To do this, they set out small cages containing moth eggs and recorded the number of eggs removed. In the future, Diane hopes to compare the overall arthropod communities between these types of sites from multiple years of sampling.

Diane traveled all over our study area during her few days in Western Minnesota.
This pitfall trap was set up at a random bb point in our study area.
  • Start year: 2023
  • Location: Prairie remnants and restorations in Solem Township, MN.
  • Overlaps with: Ground Nesting Bees
  • Data collected: species identities and richness (all arthropods, with a focus on ants), sentinel prey removal (number moth eggs removed)
  • Samples or specimens collected: All invertebrates collected in pitfall traps (stored at Augustana University, Sioux Falls, SD)
  • Products: Stay tuned!

2023 Update: Ground-nesting bees in prairie remnants and restorations

During the summer of 2023, Team Echinacea embarked on an ENRTF funded mission to better understand how prescribed fires influences solitary bee nesting habitat, food resources, and diversity is critical for providing recommendations about how prescribed fire should be used to promote pollinator conservation and healthy prairie.

We surveyed solitary bee diversity and nesting habitat before and after prescribed fires in a subset of 30 prairie remnants and 15 prairie restorations to determine how prescribed fire affects solitary bee nesting habitat and abundance. We used emergence traps to investigate composition of solitary bees in prairies. This was complemented by detailed measures of soil and litter to characterize how prescribed burning influences the nesting habitat (read more here).

We deployed emergence traps at our random points (bb points) in prairie remnants and restorations in mid-June – early September. Our deployment spanned three rotations of bb points and we put out a total of ~1,238 emergence traps.

El, Luke, and Jan, 2023 pollinator crew, deploy an emergence trap at a bb point.

As of September 28, members of Team Echinacea had processed 850 vials, 122 of which contained bees. Our preliminary catch rate is 14%! These specimens were pinned and are currently at Chicago Botanic Garden, awaiting transportation to University of Minnesota where Zach Portman, a bee taxonomist, will identify them. Team Echinacea also collected lots of non-bee bycatch while processing specimens collected in the traps. Bycatch is currently stored in our freezer at Chicago Botanic Garden.

Jan pins a bee that they found while processing vials from emergence trapping!

Ian Roberts, a M.S. student with the Echinacea Project, has taken charge of the Emergence trapping project and is currently coordinating data entry. When emergence trapping resumes in the 2024 field season, we will be well set up, thanks to detailed written and videotaped protocols made by our summer 2023 pollinator team. The prtocol can be found here: “~/Dropbox/enrtf/emergenceTrapping2023/Emergence Trap Protocol.pdf”. Video instructions are located in “~/Dropbox/enrtf/emergenceTrapping2023/exampleVideos”.

2023 Update: Random points in prairie remnants and restorations

For the ENRTF-funded research project investigating fire effects on ground-nesting bees, plant-pollinator
interactions, and other insects within fragmented prairies, Team Echinacea sampled 45 total prairie sites (30 remnants and 15 restorations).

To obtain robust inferences, it is important to sample randomly so that our sampling effort is not biased by what we perceive to be “good” or “bad” habitat, even subconsciously. To this end, we sampled at random locations within each site. At each site, we established between 30 and 72 sampling locations with unique identifiers (four-digit bbpts, for “burning and bees sampling points”). Early in the summer, before sampling at these points began, we ground truthed the points to ensure we were not choosing in places where we could not sample at all (e.g., think a big rock, a water body, a big patch of poison ivy, a gravel road, etc.).

Jared generated a large number of random points for each site, more points than we actually intended to sample. trap. We visited these points using a high precision gps unit and evaluated whether to “keep” the points and assign them a bbpt or “reject” the point if it could not be sampled safely or effectively.

Jan, 2023 pollinator team member, ground truths bb points at Torgen.
  • Start year: 2023
  • Location: prairie remnants and restorations in Solem Township, MN
  • Overlaps with: ground nesting bees, fire x fragmentation, soils in remnants and restorations, floral resources in remnants and restorations, microhabitats in prairie remnants and restorations
  • Data collected: spatial locations of accepted bb points are in “~/Dropbox/geospatialDataBackup2023/convertedXML2023/bbptsForEnrtf”. Maps of bb points are located in “~/Dropbox/enrtf/emergenceTrapping2023”
  • Samples or specimens collected: NA
  • Products: Stay tuned!

2023 Update: Microhabitats in prairie remnants and restorations

During summer 2023, Team Echinacea Echinacea characterized local environmental conditions to better understand which environmental factors are associated with good habitat for ground-nesting bees. This microhabitat assessment complemented emergence trapping for our ENRTF funded research on fire’s influence on ground nesting bees habitats. We sampled local environmental conditions near randomly placed bbpts in remnants and restorations.

We used a light meter to quantify light availability via a measure of photosynthetically active radiation. We took PAR readings at 1 meter and at ground level ~40 cm NE of the bb point. We also used a soil penetrometer to quantify soil compaction at ~40 cm NE of the bb point.

Team Echinacea conducted microhabitat assessments for three rotations of bb points (rotations 1,2,&3) across 46 sites. Over the summer, we took microhabitat assessment measurements at a total of 1,238 bb points.

Blaire, high school participant 2023, takes a light measurement at a bb point. We were particular about position and timeframe to ensure consistent measurements.
  • Start year: 2023
  • Location: prairie remnants and restorations in Solem Township, MN
  • Overlaps with: ground nesting bees
  • Data collected: light availability (par measurements) and Soil Compaction (psi measurements) are stored in ~Repos/bbnest/data/microhabitatDataCuration/curate2023MicrohabitatData.R
  • Samples or specimens collected: NA
  • Products: Stay Tuned!

2023 Update: Quantity and quality of Echinacea pollen and nectar

We’re interested in investigating what resources are available to Echinacea visitors and learning more about the pollen and nectar Echinacea produces. We hope to learn if the nutritional resources available differ before and after burns. In 2022, Britney House developed methods for collecting nectar from Echinacea using microcapillary tubes. Read more about her methods here.

During the summer of 2023, the team collected pollen and nectar samples from Echinacea angustifolia at 19 sites in and around Solem Township, MN (plants at Hegg Lake were Echinacea pallida). We searched for and shot the ~20 plants (or, if few were available, as many as we could find) at each site that were closest to a random point. We then selected ten of those plants to bag up to three of their heads with pollinator exclusion bags. Throughout the duration of their flowering, we collected pollen from all bagged plants and nectar from five of them per site.

Stuart collects nectar from an Echinacea head

Midway through the experiment (mid-July), we removed bags from some of the pollen only plants to adjust our sample size to only the five pollen/nectar plants plus two backups per site. We removed bags from pollen/nectar plants and backup plants when they were done flowering, we’d collected a cumulative 50 mm of nectar from them, or we had received less than 15 mm of nectar from the plant in the last three visits (the latter was more of a guideline than a rule, used to save time by eliminating plants that were unlikely to provide us with enough nectar for analysis). At the Hegg pallida restoration, any heads that were not originally bagged were decapitated, and all heads were decapitated upon the final removal of their bags.

Following some experimentation, we conducted nectar collection only in the afternoons, while pollen collection could be done any time of day. In total, we collected 856 vials of pollen and 580 vials of nectar from 104 plants. These were given to Rahul Roy and Margaret Medini at St. Catherine University in St. Paul, who will be doing data analysis.

Data entry for collection datasheets is complete, and verified csvs for each site can be found at: Dropbox/teamEchinacea2023/z.pollenNectarDataEntry/coreVerified. Scans can be found at: Dropbox/teamEchinacea2023/z.pollenNectarDataEntry/scans.

  • Start year: 2023
  • Location: Various prairie remnants and one restoration (Hegg Pallida) around Solem Township, MN
  • Overlaps with: bbFood, nectar experiment
  • Data collected: 
    • plant IDs (tag), location, flowering status, assessments for selection for study
      • Dropbox/teamEchinacea2023/z.pollenNectarDataEntry/scans/metaScans
    • flowering day, male floret count, pollen from N anthers in tube, pollen tube ID, tt color, nectar tube ID, quantity of nectar (mm) per floret
      • Dropbox/teamEchinacea2023/z.pollenNectarDataEntry/scans/coreScans
      • Dropbox/teamEchinacea2023/z.pollenNectarDataEntry/coreVerified
      • Dropbox/teamEchinacea2023/z.pollenNectarDataEntry/summaryData
  • Specimens collected: 
    • 856 pollen tubes (at St. Kate’s)
    • 580 nectar tubes (at St. Kate’s)
  • Team members involved with this project: Summer team 2023, Rahul Roy (St. Kate’s) , Margaret Medini (St. Kate’s)
  • Products: pending
  • Funding: ENRTF

2023 Update: floral resources in prairie remnants and restorations

During the summer of 2023, Team Echinacea conducted floral surveys at randomly selected bb points in remnant prairies and restorations. We are interested in quantifying floral resources (i.e., food for bees) and we want to understand how fire influences the diversity and abundance of flowering plants.

At each focal point (bbpt) we identified species rooted within a 2 meter radius and recorded the furthest stage of development. We measured abundance by binning a range of floral units (i.e., 1-5 flowering units got label “5”).

Floral surveys were split into “visit group A” and “visit group B”. We surveyed different random points when revisiting sites. In total, we conducted 415 floral surveys across 45 sites.

Liam Poitra, a 2023 Summer Research Experience for Undergraduates (REU) Participant, contributed to this research project investigating the effects of fire on diversity and abundance of flowering plants. Liam assisted in fieldwork and data organization. Inventory, protocols, and blank datasheets for floral assessments are located in ~/Dropbox/enrtf/floralSurveys2023.

Liam Poitra, REU 2023, navigates to a floral assessment focal point at Staffanson Prairie Preserve. The 2-meter stick he carries will help keep track of what is in the bounds for survey.
  • Start year: 2023
  • Location: prairie remnants and restorations in Solem Township
  • Overlaps with:  Ground nesting bees
  • Data collected: Floral survey datasheets can be found in ~/Dropbox/teamEchinacea2023/z.scanned/”
  • Samples or specimens collected: NA
  • Products: Stay tuned!

2023 Update: soils in remnants and restorations

In July, 2023, a team from Minnesota State University, Mankato visited Team Echinacea to sample prairie soil. They are investigating how fire and management history influences physical, chemical and biological soil properties. Differences in soils may also help explain plant fitness and native bee nesting patterns. After three hot days, 263 samples were collected from 28 sites!

Back in Mankato, four undergraduate students processed the soil samples by sieving and weighing out the field collections. The preliminary results show soil bulk density is lower in remnant prairies compared to restored prairies. This makes sense in that remnant prairies have retained their organic-matter rich topsoil, infiltrated with plant roots and filled with pore spaces that develop over time in natural prairies. The soil bulk density is also lower on flat (no slope) topography, in part due to illuviation (deposition) of nutrients and organic material from nearby sloped areas.

The team hopes to continue its investigations to understand which soil properties are sensitive to different management histories and how the patchwork of fragmented prairies in the region vary in carbon, nitrogen and biological activity. These data should provide foundational information for many additional projects.

The Mankato soil team gathers around a bbPoint to discuss sampling. The team visited bbPoints in remnants and restorations over a 3 day period.
  • Start year: 2023
  • Location: : 28 study plots on private, federal and state land with different land use histories: remnant and restored grassland
  • Overlaps with: Fire x Fragmentation; Ground Nesting Bees
  • Data collected: Soil bulk density, maximum water-holding capacity, gravimetric soil moisture content, soil aggregate stability (SLAKES), total organic C, total N, inorganic N (plant available forms: ammonium and nitrate), aerobic respiration rate (proxy for microbial activity and decomposition)
  • Samples or specimens collected: Topsoil bulk density and additional soil (top 15 cm) for each bee nesting trap
  • Products: Stay tuned!

pollen and nectar = food for thought

Many plants, including Echinacea angustifolia, flower vigorously during the summer after a prescribed burn. We’ve demonstrated that the benefits of fire for seed production, in many circumstances, are bigger than just the increase in flowering. The additional boost to seed production results from better pollination after fires compared to other times. Now we are trying to figure out what’s going on with pollination–why is it better after a fire? It might be related to pollen or nectar, which are foods for the bees that pollinate Echinacea. Here are two possibilities: 1) after a fire, plants produce more or better pollen or nectar which draws in bees from farther away, so the plants get more visits and better pollination, presumably the bees are happier with abundant & healthy food. 2) after a fire, plants produce less or lower quality pollen or nectar which means bees need to fly to more plants to get a decent meal, so the plants get more visits, and the bees are probably frustrated with skimpier meals and bad food. The third possibility is that plants produce the same quality and quantity of pollen & nectar regardless of fires.

Over the summer we systematically collected pollen and nectar from many Echinacea plants in many populations (19) over many days. Our goal is to evaluate how fires affects the quality and quantity of pollen & nectar produced by Echinacea plants. We are getting close to wrapping up data-entry for our field collection of pollen and nectar from Echinacea angustifolia. Here’s a summary of data-entry progress so far…

[1] "11 sites of data entered twice & verified"

[1] "138 pages of data entered twice & verified"

     site tagCt pageCt 
1      aa     6     11 
2  cg-p01     5     14 
3    eelr     5     13 
4   hulze     6     17 
5   hulzw     5     13 
6  hutche     5     13 
7  hutchw     5      9 
8      kj     6     11 
9   koons     5      9 
10    p02     5     13 
11 p08-tp     5     15 

Each “tagCt” is the number of Echinacea plants we sampled at each site. We will keep you posted!

Funding for this project was provided by the Minnesota Environment and Natural Resources
Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources

Oops, all hornets!

Today, while deploying emergence traps, we avenged our recently stung colleague (Ellysa Johnson). One of our randomly selected points was directly upon a hornets nest (a few are seen in this photo, but tens were present and buzzing furiously). Miraculously, neither of the crew members present were stung. Let this day mark our revenge.

Also we did demo.

Farewells Sting

Today was Harrison’s last day with us 🙁 Stuart made a prairie-inspired cake to honor his time with the project. He is returning to teach young minds about ecological research. Farewell, Harrison, and good luck!

The team also conducted floral abundance surveys. Essentially, we want to see how many plants (and what kinds) may be associated with ground-nesting bees. That requires feet on the ground to estimate abundances and identify plants.

Lastly, a battle occurred today. While the crew did demography of echinacea plants- where we record data on this year’s flowering plants- I was stung by two wasps. Luckily, Lindsey was prepared to retaliate, though it wasn’t necessary.

All in all, farewells can sting, but at least there’s cake in the end.