University of St. Thomas
OP-10: Biodiversity

The St. Paul campus is adjacent to the Mississippi Gorge Regional Park portion of the Mississippi National River and Recreation Area. According to the National Park Service, "The Mississippi River's character changes more throughout the 72 mile (115 km) stretch of the Mississippi National River and Recreation Area than anywhere else along its 2,350-mile course. The river enters the northern corridor as a free-flowing prairie river and moves downstream to plunge over St. Anthony Falls and into the river's narrowest gorge. Eight and one-half miles later, the river exits the gorge to become the country's dominant floodplain river and part of the largest inland navigation system on earth. Through the eight and one-half mile gorge, the Mississippi drops more than 110 feet, the river's steepest descent anywhere. The river's rapidly changing character explains why the national river and recreation area has such a unique concentration of nationally significant resources. " Source: "Learn About the Park." Mississippi National River and Recreation Area. National Park Service, 13 Dec. 2016. Website: https://www.nps.gov/miss/learn/index.htm

A mere two-lane road separates the Mississippi National River and Recreation Area from the westernmost block of University of St Thomas’ property. This 4-acre piece of land is managed as parkland and consists mainly of trees and sod except for a 10,000 square foot slice that is the heart of the UST Pollinator Path – the Biology Stewardship Garden and several Pollinator Path beds. The species diversity of insects at this site is greater than at any of the other sites on campus. Our working hypothesis is that this richness is due to its proximity to the Mississippi river. We see the other beds on campus as habitat fragments that provide additional forage to the pollinators that may originate from these nearby natural areas.

The pollinator populations are assessed regularly from May-October. We have documented several at risk pollinator species on campus foraging on the flowers in our Pollinator Path beds. These include: Bombus affinis (Rusty Patched Bumblebee - Endangered), Danaus plexippus (Monarch butterfly - candidate for Endangered status) Bombus fervidus (Golden Northern Bumblebee - Species of Greatest Conservation Need), Leaf-cutter bees, Mason bees (at risk for extinction per NatureServe).

The Pollinator Path beds are managed by the Biology Greenhouse Manager, and co-founder of the Pollinator Path, Catherine Grant. The beds are protected areas designed to attract the Rusty-Patched bumble bee and many other native pollinators. There are currently thirteen beds designated as Pollinator Path beds. These beds are planted with native and some non-native perennials specifically selected to provide forage for Minnesota native bee species from May through October. In total, there are over 89 perennial species in the designated beds, and 46 annuals, all selected for their value to pollinators. In particular, we have been experimenting with the addition of specific native plants that are known to attract the Black and Gold Bumblebee, Bombus auricomis, the second-most populous bumblebee on campus. Our largest site, the Pollinator Garden, is adjacent to the Mississippi River and is our richest site for species diversity and population numbers. We are working towards creating a corridor of habitat gardens from the river to the main campus.

We conduct regular population surveys from May through October of all the Pollinator Path beds using the Xerces Society methodology: walking at a certain pace and recording a count of which pollinators are on which plants. We have been tweaking our plantings based on our floral preference findings. We have several sets of data based on this method. One set is collected each September by students in a Conservation Biology class who do a count on a single day by identifying pollinators in broad categories such as "butterfly, bumblebee, honeybee," etc. Another set, taken by Pollinator Path co-founder Doreen Schroeder, is done on a weekly basis from June through September. She collects data on the floral preferences of a more fine-tuned set of pollinators per the Xerces Society's broader categories of pollinators. She has data going back to 2016. Since 2022, we have employed student workers on the Pollinator Path, and they have learned to identify bumblebees down to the species level, and other bees by genus and/or groupings designated by the Xerces Society. We have two years of data from them on the floral preferences and population trends over the course of summer on our most visited Pollinator Path sites. The students have also conducted specific studies one day per week over summer where they collect floral preference/population trend data at regular intervals over the course of one seven-hour day. In 2023, we have been able to continue the weekly survey through October allowing us to document the decline in various bumblebee populations come fall. All of the data help us recommend and install more plants to satisfy the needs of pollinators at different times of year.

The student-collected assessments date back over five years and include data collected before the Pollinator Path was established, giving us an important benchmark. The data shows a threefold increase in bumblebees since the Pollinator Path introduced new forage, and a six-fold increase in honeybees – although that may be attributable to more managed hives in the surrounding St. Paul neighborhoods.

The data collected by Doreen Schroeder spans seven years thus far and is noted for the level of specificity as to bee type and flower species. The new data collected by students since 2022 collects floral preference and population numbers at the same level of specificity and gives us insight into whether or not pollinator foraging activity is affected by the time of day, weather conditions, shade/sun on a particular patch of flowers, etc. We have also observed and documented the number of flowers visited per minute and the length of time any one bee (Bombus auricomis) spends foraging on our keystone perennial, Monarda fistulosa.

We have added approximately 2300 sf of beds to the Pollinator Path in the last two years. The total area dedicated to pollinator habitat now totals 16,800 sf. The programs in place to protect pollinators and established habitats include: 1) The 'branding' of the habitat sites as the "Pollinator Path" including signage, website links, etc.; 2) support from the Biology Department to hire student workers in the summer to do maintenance and research; 3) support from the Facilities Department to allow continued use and expansion of sites otherwise under the domain of the Grounds crews; 4) the use of the Pollinator Path sites as a living lab for dozens of undergraduate class projects administered through the Sustainable Communities Partnership/Office of Sustainability Initiatives; 5) the development in 2023 of a set of credentialing badges for internal development - the Pollinator Path Principles and the Pollinator Path in Practice badges; 6) Pollinator Path tours offered to the larger community as well as to St Thomas students, staff, and faculty. 7) The publication of a booklet entitled Exploring Pollinator Pathways created by a Biology class and an artist-in-residence.