The Plants of Baxter State Park

A field guide to the plants found in the more than 200,000 acres of wilderness and public forest in Piscataquis County known as Baxter State Park.

Maine’s Baxter State Park is one of the most ecologically diverse and beautiful protected sites in the Northeastern United States. The Plants of Baxter State Park presents scientific descriptions of 857 plant species.

The Park has more than 40 peaks and ridges, numerous streams, more than 75 lakes and ponds, many waterfalls, wetlands, and bogs, and more than 215 miles of trails. The most notable mountain is the Katahdin massif, the highest mountain in Maine.

Despite the large number of rare plants and the great diversity of habitats, a complete inventory of the vascular plants growing in Baxter State Park has never been conducted until now.

Methods

To compile a list of vascular plants growing in Baxter State Park, we relied on three primary research methods: literature review, herbarium research, and field surveys. We began by completing an exhaustive search of published literature and unpublished reports for data on plants found in the Park. We compiled this information into a plant list by Township within the Park. We also carried out research at several herbaria within New England to find specimens from past explorations in Baxter State Park. This brought the existing number of documented species in the Park to nearly 550.

From 2011 to 2014, we conducted field inventories in the park with the goal of adding to this baseline list of species. The field surveys used a citizen science approach developed by Mittelhauser and Dibble in collaboration with Baxter State Park staff. Research teams spend more than 4,200 hours in the field documenting the flora of the Park. Each team consisted of a professional botanist working with one to five volunteers. Teams developed plant lists for each area explored during the field surveys. They took more than 17,000 digital photos as vouchers of plant observations, as well as GPS points to document where uncommon and rare species were found. Teams also gathered data on the abundance of each species and the habitats in which each occurred. As research progressed, we used a gap analysis approach to focus our efforts on unexplored areas and habitat types.

Over the course of four years, we documented approximately 300 species that had not previously been reported from Baxter State Park bringing the total flora of Baxter State Park to 857 species. This represents about a third of the 2,490 plant species known to grow wild in Maine and over half of Maine’s 1,527 native plant species. These are remarkable totals for a park that covers less than 1% of Maine’s land area. This level of diversity coupled with the Park’s forever wild management, suggests that Baxter State Park will have a lead role to play in the long-term conservation of Maine’s flora.

The flora of Baxter State Park is notable for its large percentage of native species of the 857 total species found in the Park, 745, or 87%, are considered native to Maine. This is a significantly higher percentage of native species than for Maine’s overall flora, which is about 61% native (Haines 2011). Only 7 species found in Baxter State Park — less than 1% of the Park’s flora — appear on the list of invasive or potentially invasive species maintained by the Maine Natural Areas Program. This is an exceptionally small number of invasive species for an area with 65,000 visitors annually. Unfortunately, it is very likely to increase over time.

This guide includes 86 species of trees and tall shrubs; 508 species of wildflowers and low shrubs; 60 Ferns and other spore-producing plants; and 203 graminoids, including sedges, rushes, and grasses. 69 species of plants and Baxter are listed as rare, threatened, or endangered by The Maine Natural Areas Program. These plants typically occur in very specific habitats, such as exposed to Alpine ridges, enriched Northern hardwood forests, or circumneutral bedrock outcrops.

This field guide presents our current understanding of the plants growing in Baxter State Park. Although it represents thousands of hours of careful research, we hope you view this guide as a beginning rather than an ending. Plant communities change over time as new species arrive and other species can no longer find suitable habitat. Despite the best efforts of Baxter State Park staff new invasive species will likely arrive and establish a foothold. Ecosystems in Baxter State Park will change in response to global climate change, although we do not yet know exactly how. The data generated by this project will provide a baseline for measuring that change, and a tool for understanding.

(Excerpts from the introduction to The Plants of Baxter State Park)