Vegetation Re-Survey of the Brule River Watershed in NW Wisconsin: 1852 – 2017. 4.12.22

Paul Hlina spoke about a plant survey of the Brule River watershed that he conducted in 2015-16 while at the Lake Superior Research Institute. He shared photos of many beautiful plants and some of their fascinating biology, but even more than that, Paul was a storyteller. He described the serendipitous series of events that led to his Brule River survey. The first was when he was running a native landscaping business and propagating and planting a variety of flowers and shrubs, but wanted to learn more about native grasses, sedges, and rushes. The herbarium at the University of Wisconsin Superior invited him to peruse the specimens there any time to help learn the subtle distinctions between different species. While looking through the specimens, his eye was caught by old ones, including a number collected from the Brule River in the 1940s by John Thompson. Because the labels described the locations where they were collected, Paul kept in mind the possibility of returning to those locations to see what’s growing there now.

Years later at a high school basketball game Paul was invited to pick up a box of old papers from the Brule River State Forest office that had been left by retired UWS biology professor, Donald Davidson, who the herbarium is named after. Looking through the box, he found it contained original datasheets from a forest vegetation survey of the 1960s. Dr. Davidson had revisited the locations of the Brule River Survey conducted by John Thompson, whose specimens Paul had seen years before. The 1940s Brule River Survey investigated the physical, chemical and biological factors of the river’s watershed that could be causing the decline in the river’s fish populations. With botanical data collected twice already, Paul realized a third visit after 50 years could be informative.

Thompson had made collections, and they meandered each area, recording every plant species observed and making collections for the herbarium. These were in three habitat types: boreal forest, pine barrens, and cedar swamp. With more people searching, they found more plant species than Thompson did, including many more introduced species, but 92 of Thompson’s species were not found. These were mostly early successional species that have been shaded out as the pine barrens have grown into dense forests in the absence of recurring fire. In addition to diminished pine barren habitat, they also found a loss in amount of cedar swamp. Some areas where cedars were cut in the early 1900s still have not regenerated. On the other hand, the amount of boreal forest has begun to recover in recent decades.

In 2015-16 Paul’s team of experienced botanists revisited 21 sites where Thompson had made collections, and they meandered each area, recording every plant species observed and making collections for the herbarium. These were in three habitat types: boreal forest, pine barrens, and cedar swamp. With more people searching, they found more plant species than Thompson did, including many more introduced species, but 92 of Thompson’s species were not found. These were mostly early successional species that have been shaded out as the pine barrens have grown into dense forests in the absence of recurring fire. In addition to diminished pine barren habitat, they also found a loss in amount of cedar swamp. Some areas where cedars were cut in the early 1900s still have not regenerated. On the other hand, the amount of boreal forest has begun to recover in recent decades.

Among the many interesting plants Paul’s team discovered were a new Douglas County record of Early Horse Gentian (Triosteum aurantiacum), which is typically found farther south and a new state record of Hairy Lettuce (Lactuca hirsuta), which is typically found farther east. They also found a fair number of the threatened Oval-leaf Milkweed (Asclepias ovalifolia), which re-appears after trees are logged from the pine barrens.