The Glacial Ridge IBA includes a large complex of prairie grasslands and wetlands at the southern extent of Minnesota?s Aspen Parkland region. The Aspen Parkland is a unique transition zone between the prairie and coniferous forest biomes, characterized by a mosaic of prairie, sedge wetlands, and aspen groves. Much of the IBA lies at the edge of Glacial Lake Agassiz, which covered northwestern Minnesota, eastern North Dakota, and large portions of Ontario and Manitoba at the end of the last Wisconsin glacial period. The topography of this IBA is extremely level, with the only relief provided by ancient beach ridges rising a few feet above the otherwise flat terrain. Glacial Ridge IBA is located in Polk and Red Lake Counties in northwestern Minnesota, approximately 10 miles east of Crookston. The IBA is roughly bounded on the north by U.S. Highway 2, Polk County Hwy. 12 to the east, Highway 102 on the west, and County Rd 1 to the south except for some outlying parcels north of Highway 2 which lie in Red Lake County. Towns near the IBA include Mentor and Fertile.
Historically, fire played an important role in maintaining the open character of the vegetation in this landscape. The dominant trees in the region are quaking aspen and bur oak, typically rather small in stature, occurring in groves interspersed with prairies and wetlands. Fire suppression has allowed many of these areas to develop into dense forests of larger trees. Much of the native prairie is categorized as ?brush prairie? due to a significant short shrub component. Dry prairie, wet prairie, and sedge habitats are also important in this region.
This IBA is a complex of sites owned and managed by the Minnesota DNR as Wildlife Management Areas and Scientific and Natural Areas, the U. S. Fish and Wildlife Service?s Glacial Ridge National Wildlife Refuge, and The Nature Conservancy. These partners are working together to manage these lands for a common purpose and the IBA boundaries reflect this work area.
Glacial Ridge is one of the top sites in Minnesota for prairie birds, particularly species dependent on wet prairie and sedge wetlands. Surveys for breeding birds, particularly nongame species, have been somewhat limited by the areas remoteness. However 164 species have been recorded, of which 149 are likely breeding. Sixteen State listed species have been recorded during the breeding season on the IBA including the most recent records of Burrowing Owl (state endangered) and significant populations of Greater Prairie Chickens, Marbled Godwits and Yellow Rails. A total of 43 Species of Greatest Conservation Need are found in the IBA with relatively high numbers of American Bittern, Upland Sandpiper, Le Conte?s Sparrow, and Bobolink. This area has fall migratory Sandhill Crane roosts with 2,000 ? 6,000 birds documented and is within the important NW Minnesota crane breeding range.
More than 53 bird surveys (point counts and species lists) were conducted within the IBA by MN DNR Minnesota County Biological Survey (MCBS) during the summer of 1995. Additional surveys were conducted on DNR Scientific & Natural Areas (SNA) in 2005. However, many areas have not been surveyed. The maximum numbers listed below represent the number of MCBS surveys at which a species was detected; actual numbers of breeding pairs are undoubtedly much higher.
MN-1d) migratory stopover: Two Sandhill Crane fall migratory roost sites have been identified within this IBA, at Dugdale WMA and Burnham Creek WMA. A total of 2,000 ? 6,000 cranes have been documented using these roosts.
MN-2a) Species of conservation concern (State listed species): This IBA supports a very diverse assemblage of rare bird species, many of which occur regularly in relatively high numbers. This area provides important habitat for Yellow Rail, Wilson?s Phalarope, Short-eared Owl, and Nelson?s Sharp-tailed Sparrow. Outside of Felton Prairie, this is the only site in Minnesota with multiple records of the state-endangered Sprague?s Pipit and Baird?s Sparrow. Burrowing Owls nested in the IBA in 2007, and Whooping Cranes have also been observed on a couple of occasions.
The IBA is also one of Minnesota?s top sites for Greater Prairie-Chicken. MN DNR lek counts in 2009 found 76 males within the boundaries of the IBA and 90 males within approximately 5km of the IBA. In 2010 MN DNR lek counts found 45 males within the boundaries of the IBA and 51 males and 3 females within 5 km of the IBA.
During the breeding season, sixteen state-listed species have been documented on the IBA:
Endangered: Burrowing Owl (1 record), Sprague?s Pipit (2 records), Baird?s Sparrow (2 records), Henslow?s Sparrow (1 record)
Threatened: Trumpeter Swan (1 record), Wilson?s Phalarope (8 records), Loggerhead Shrike (1 record),
Special Concern: Greater Prairie-Chicken, American White Pelican (non-breeding), Bald Eagle, Peregrine Falcon (migrant), Yellow Rail (43 records), Marbled Godwit (14 records), Franklin?s Gull (non-breeding), Short-eared Owl (5 records), Nelson?s Sparrow (9 records)
MN-2b) Species of conservation concern (non-listed species): Fourteen non-listed species of concern have been documented on the IBA. At least four species meet the threshold required to meet this criteria (American Bittern (11+ records), Upland Sandpiper (48 records), Le Conte?s Sparrow (36+ records), Bobolink (48+ records),). Note that the numbers listed represent the number of individuals documented during MCBS surveys of a relatively small portion of the IBA, so actual populations are undoubtedly significantly higher based on the amount of suitable habitat present.
The ten other species of concern not meeting the threshold requirement include: American Black Duck, Northern Pintail, Swainson?s Hawk, Sharp-tailed Grouse, American Woodcock, Black Tern, Black-billed Cuckoo, Whip-poor-will, Olive-sided Flycatcher, Dickcissel
MN-3) Species assemblages of rare, threatened, or unique habitats: Glacial Ridge IBA has significant amounts of three rare, threatened or unique habitats and intact avian communities representing these habitat types are found here.
Aspen Parkland (sedge wetland, brush prairie, oak savanna, aspen openings)
Sedge Wetland (rich fen, poor fen, wet meadow)
Native Prairie (dry, mesic, wet prairie)
The reduction of land management is a threat in this area due to the loss of CRP lands occurring in the 2012 Farm Bill. A reduction of acreage enrollment, from 32 million to 25 million over the next 5 years, equates to a significant loss in protected lands. With the turnover of CRP either back into agriculture or to future development, loss of quality avian habitat is a high level threat which is directly related to the intensification and potential expansion of agriculture. Other lower level threats include the surface gravel extraction easements within the Glacial ridge IBA which are fairly contained and not likely to expand. Pesticide threats are most likely to occur near road right of ways and railroad properties. Likewise, invasive or non-native plant threats will be a continuous problem especially near travel corridors.
Prior to 2000, the area encompassed by the IBA consisted of numerous WMA?s, The Nature Conservancy?s (TNC) Pankratz Prairie and Pembina Trail Preserve SNA, and one federal Waterfowl Production Area. In August 2000, The Nature Conservancy purchased 24,270 ac of land, connecting several of the existing management units. Since then, TNC has been working with numerous partners to restore natural vegetation within this ?Glacial Ridge Project?, with a goal of 15,000 acres of restored prairie and 8,000 acres of restored wetlands. In 2004, the Glacial Ridge NWR was established beginning with land sold/transferred to the USFWS from TNC. The statutory boundary of the Glacial Ridge NWR encompasses 35,575 acres, of which 2,790 acres is currently owned by USFWS.
Currently, of the IBA?s 93,120 acres, approximately 15 percent (13,288 acres) is owned and managed by the Minnesota Department of Natural Resources (DNR) Section of Wildlife. Other important tracts include the 2,267 acre Pembina Trail Preserve SNA (part joint w/ TNC) and the TNC?s Pankratz Memorial Prairie (934 acres). Two Waterfowl Production areas, Melvin Slough and Thorson, part of the USFWS Detroit Lakes Wetland District, are 320 and 875 acres, respectively. The total Minnesota DNR, U.S. Fish & Wildlife Service, and TNC ownership is currently 37,451 acres (41% of the IBA).
Outside of public lands, most of the grasslands within the IBA are in CRP. As of 2007, Conservation Reserve Program (CRP) enrollment amounts to 8,400 acres, and 139 acres of land are under Reinvest in Minnesota (RIM) easements. An additional 13,519 acres are in Wetland Reserve Program easements (NRCS). The semi-natural state of these intervening areas provide important connections between many of the large blocks of aspen parkland vegetation, and provided important habitat for open country bird species.
Habitat cover type percentages are from GAP, a vegetation cover map which has some trouble distinguishing native prairie from non-native grassland. The GAP grassland (and cropland) percentage is also affected by current CRP acreage. Total GAP grassland cover was 14% of the IBA, with 23% cropland. However, much of the 2007 CRP acreage, is in areas categorized by GAP as cropland. Since most CRP acreage is grassland, the actual percentage of grassland is higher, and cropland lower, than indicated by GAP. The percent grassland and cropland in the Habitat and Land Use table have been adjusted to reflect CRP grassland cover (as of 2007). GAP does not distinguish between marsh (cattails, bulrushes, etc.) and wet meadow (broad-leaved sedges), and often has trouble separating out rich fen (narrow-leaved sedges). GAP cover for broadleaf sedge/cattail and rich fen was 12.5% and 3.5%, respectively. The distinction between sedge wetlands and marsh is important because true sedge/wet prairie specialists like Yellow Rail, Le Conte?s Sparrow, and Nelson?s Sparrow, rarely, if ever, inhabit cattail-bulrush marshes.
MCBS plant ecologists have done preliminary mapping of native plant communities for Pennington and Polk counties, covering all but the Red Lake County portion of the IBA. MCBS native plant communities are categorized and mapped following the vegetation classification developed by the Minnesota DNR (MNDNR 2005. Field Guide to the Native Plant Communities of Minnesota: The Prairie Parkland and Tallgrass Aspen Parklands Provinces). Mapped native plant communities must meet certain quality criteria, so forests, grasslands, and wetlands showing signs of disturbance may not be delineated. Within the IBA, MCBS has mapped the following native plant communities not differentiated by GAP: 843 acres of upland native prairie, 1,034 acres of wet native prairie, 52 acres of wet meadow, 20 acres of rich fen (narrow-leaved sedges), and 1,751 acres of mixed cattail marsh.