Chapter 3: Refuge Environment Chapter 3: Refuge Environment Introduction Tamarac NWR encompasses 42,738 acres of land and waters in the glacial lake area of northwestern Minnesota. The Refuge is located in Becker County, 18 miles northeast of Detroit Lakes, in the heart of one of the most diverse ecological transition zones in North America, where northern hardwood forests, coniferous forest and tall grass prairie converge. Between 10,000 and 10,500 years ago, receding gla- ciers left behind the rolling ridges and deep depres- sions that became a woodland area complemented by lakes, rivers, bogs and marshes and is now Tama- rac NWR. The primary ecological drivers influenc- ing the plant and wildlife populations of the Refuge are the climate, hydrology, and natural disturbances Frog. Photo Credit: Michele Gedgaud such as fire, disease and wind events. Other Units Administered and after the Refuge’s establishment, particularly from agriculture, timber harvest, roads, and water Wilderness Area control. Although Tamarac NWR cannot be The Tamarac Wilderness Area was established described as pristine, it is largely an intact, health by law in 1976. The Wilderness Area is managed and functioning ecosystem that just does not meet under the provisions of the 1964 Wilderness Act as a the strict definition of suitable lands. unit of the National Wilderness Preservation Sys- tem. That is, it is “an area where the earth and its Areas of Special Designation community of life are untrammeled by man, where The Research Natural Areas were designated in man himself is a visitor who does not remain” (The 1972 with some general management and protection Wilderness Act, September 3, 1964; (16 U.S.C. 1121 criteria. Research Natural Areas are managed to (note), 1131-1136)). Staff carries out no active man- maintain the natural features for which they were agement in the Tamarac Wilderness Area, but does established and to maintain natural processes; conduct research in the unit. The management therefore, management of the Refuge RNAs is strategy for the wilderness area calls for passive through protection against activities which directly management with natural succession allowed to or indirectly modify ecological processes or alter the take its course. In theory, examples of almost all for- type or feature which is being preserved. Manipula- est types on the Refuge would be preserved in this tive practices such as grazing, prescribed burning, one single complex of wilderness. timber cutting, road construction and the use of chemical for plant, insect and disease control are not Wilderness Review permitted unless such are necessary to maintain the As part of the CCP process, we reviewed other type or process for which the RNA was established lands within the legislative boundaries of Tamarac or to prevent the spread of insects and disease. NWR for wilderness suitability. No additional lands There is not a lot of flexibility to manage the wilder- were found suitable for designation as defined by ness area or RNAs in regard to habitat manage- the Wilderness Act of 1964. Many of the lands have ment; however, there remains a tremendous amount been substantially altered by humans, both before of flexibility in the strategies and tactics that can be Tamarac NWR and WMD / Draft CCP 12 Chapter 3: Refuge Environment Figure 2: Areas of Special Designation, Ecological Context Tamarac NWR Situated along the backbone of Minnesota, the Refuge lies within a mile of the continental divide, which separates the Mississippi and Hudson Bay watersheds. Lake Itasca, the headwaters of the Mis- sissippi River, lies approximately 25 miles northeast of the Refuge. Many Refuge lakes and rivers contain large wild rice or “manoomin” beds that produce abundant waterfowl food in most years. Upland veg- etation is diverse due to the Refuge’s location in the transition zone between northern hardwood and coniferous forests, which levels off into tallgrass prairie, or the Red River Valley, a mere 10 miles west of Tamarac NWR (Figure 3 on page 14). Hence, many species of plants and animals are at the extreme western edge of their range. Historic Land Cover Over thousands of years, the area’s vegetative communities have undergone perpetual change, pri- marily due to climatic changes following glaciation. “Pollen core” records and pre-settlement conditions and are often the best or only sources of information on pristine, baseline conditions and natural environ- mental and biotic variability. This information is sometimes used as a reference of available vegeta- tion at the various time periods. Pollen core records provide a long-term context of what the landscape was like since the time of the last glaciation, but are often limited in availability (Tester 1995). The pre- settlement vegetation represents a “snap-shot” in the time of the era immediately prior to European used to manage these areas (ie: fire suppression tac- settlement within the area and by itself it does not tics, invasive species control, etc.). adequately represent changes in vegetative commu- The area bordered by the Blackbird Auto Tour nities and their associated processes over time. and County Highways 29 and 26 was internally des- Pollen records from Itasca State Park, which had ignated as an “Old Growth Area” in the early 1990s. the same glacial history and climate as the Refuge The goal was to set aside a significant habitat block due to its proximity, indicate transition in dominant in addition to the Wilderness Area and RNAs that plant community types since the retreat of the Wis- would be allowed to develop and be managed for consin glacier (Tester 1995). Immediately following characteristics of old growth forest. Prescribed fire this retreat, the land was likely barren and void of was not excluded as a management tool, but large vegetation; however, within a few years coniferous scale timber harvests would not be allowed. Silvicul- trees such as spruce and pine began to dominate the tural treatments would be used to create small can- landscape due to the cool and moist environment. opy gaps of up to one acre in size to replicate wind These forests dominated the landscape until about throw events. 8,000 years ago, when more herbaceous species There is also a significant area designated as became prevalent. This indicates the presence of a sanctuary for the benefit of breeding birds savanna with scattered oak trees and large open (Figure 2). The lower one-third of the Refuge sup- areas of prairie due to warmer and drier conditions. ports visitor use activities and the sanctuary occu- Other studies indicate this warmer, drier period was pies the northern two-thirds of the Refuge. The characterized by extremely variable climatic condi- sanctuary is closed to the general public from March tions from drought to abundant precipitation 1 to September 1 each year. Approximately the (Almendinger 1988). Several thousand years later, northern half of the Refuge lies within the original the area became cooler and wetter again, giving rise boundary of the White Earth Reservation, which to an expansion of the coniferous forest (primarily was established in 1867. red and white pine) and other deciduous trees back into the area with a decrease of prairie. This condi- Tamarac NWR and WMD / Draft CCP 13 Chapter 3: Refuge Environment Figure 3: Ecoregion of Tamarac NWR tion has persisted until the present, with some destroyed or substantially altered. Although for- increase in hardwoods in recent years. Peatlands ested communities have changed in composition formed approximately 3,000 years ago. These pollen across much of northern Minnesota following nearly core records provide a testament to the range of 150 years of logging, opportunities exist for sustain- natural variability of vegetation within the larger able management and conservation of forested com- landscape. munities in large areas. When Euro-American settlers first arrived in Minnesota Ecological Classification System Minnesota in the mid-1800s, native plant communi- Recently, the Minnesota DNR established an ties occurred in complex patterns across the entire Ecological Classification System (ECS) for land landscape. Francis M arschner (1882-1966) mapped classification and ecological mapping for Minnesota the pre-European settlement vegetation of Minne- based upon the national hierarchy of nested units sota based on Public Land Survey notes and land- (ie: Provinces, Sections, Subsections, Land Type scape patterns. His maps provide a reference Associations, etc.). The vegetation classification is condition of the vegetation in the area of Tamarac hierarchical with units describing broad landscapes NWR prior to European settlement. Caution should to local native plant communities (NPC). The Min- be used when interpreting these historic vegetation nesota ECS enables land managers to consider eco- maps because of the scale and base data that logical patterns for broad landscapes or for a single Marschner used, but it does provide a good context small local unit, (ie: forest stand or native plant com- of historic forest types. Based upon Marschner’s munity) which is valuable at multiple planning levels interpretation for the area that is now Tamarac and crucial to the long-term ecological integrity and NWR, pre-European settlement cover types were stability of these ecosystems. One of the most comprised of mature stands of red and white pine, important considerations in the ECS classification is jack pine barrens, aspen-birch, mixed hardwoods, the inclusion