Wetland Monitoring of the Two Medicine Watershed

Report prepared for the US Environmental Protection Agency, Blackfeet Environmental Office

This page intentionally left blank

Wetland Monitoring on the Blackfeet Reservation

The Two Medicine Watershed wetlands were assessed during the fifth year of rotating watershed monitoring on the Blackfeet Reservation. The purpose of wetland monitoring is to evaluate wetland condition in a range of wetland ecosystem types within a watershed. High quality examples of wetlands can serve as protection, conservation and reference standard wetlands for restoration work in similar wetlands. Factors that contribute to wetland impact can be examined in the field and through data analysis to determine trends in wetland condition and develop actions that can restore wetland condition. The scope and severity of wetland disturbances can be used to project future wetland condition and functionality within the watershed and development management actions that can preserve, maintain or restore wetlands within a region. In conjunction with climate data, wetland loss due to compounding effects on wetland condition can be projected within discreet precipitation zones within the watershed. These efforts will assist wetland protection and restoration efforts to conserve and improve water storage, wetland functionality and preserve to the greatest degree possible, wetlands and water dependent wildlife and flora.

The Two Medicine Watershed Overview

Geology and Soils

South of the Two Medicine Valley, geology of the Rocky Mountain Front of the Lewis and Clark National Forest is composed primarily of Cambrian to Cretaceous age limestone bedrock, with youngest age rock exposed east of the Lewis Overthrust. Mountain peak geology of the Badger Two Medicine area of the Lewis and Clark National Forest consists of the Blackleaf and Kootenai Formations, with exposed Mount Pablo Formation occurring above Dog Gun Lake. Landslide deposits occur beneath mountain summits of the Kiyo Crags and Half Dome Peaks of the Badger-Two Medicine Area of the Lewis and Clark National Forest. Foothills and slopes beneath mountain summits in the Lewis and Clark NF are largely marine shales thinly overlain by limestone or occur solely as exposed marine shales.

Foothills in this region are composed of the Marias River Shale Formation, followed by the Two Medicine and Virgelle Sandstone Formations. Further to the east, the Two Medicine, Bear Paw Shale, Virgelle Sandstone and Saint Mary Formations occur in the central portion of the watershed, followed by the Two Medicine Formation in the easternmost section of the watershed.

Glacial till deposits from Piedmont glaciers occur above Cretaceous age sedimentary bedrock. Exposed bedrock occurs near the Park boundary, Two Medicine Ridge and exposed sandstone bedrock in the central and eastern thirds of the watershed. Till deposits from the Continental Ice sheet occur along the Two Medicine River and range from 15 to 70 ft deep in the lower reaches of the river. In the southeastern portion of the watershed, till occurs above bedrock and is overlain by lake sediments, near the mouth of the Two Medicine River (Cannon 1996). Alluviums and gravels occur within the river floodplain and tributaries.

Wetland Soil Features

Wetland soils in the Two Medicine watershed are variable due to influencing geology. Wet meadows, fens and floating peat mats in upper montane aspen and mixed coniferous potholes typically have an organic layer averaging 37 to-60 cm overlying silty gravels and cobbles or overlying predominately clays, clay loams or silty clays. Clay layers often contain significant cobble or gravels, depending on their location within the watershed. Sands and sandy loams with high rock and cobble content predominate in river floodplain wetlands dominated by willows or cottonwood. Foothill area potholes and depressions have silty clay to clay layers up to 47 cm deep overlying glacial till and outwash, and often contain high amounts (r5-75%) redox concentrations as well as depletions in pure clay sub-layers.

Climate

From 1911 to 2010, annual average precipitation averages 31.4 cm (12.4 in) at Valier near the eastern edge of the watershed, with an average annual snowpack 83.5 cm (33.2 in) at Valier (Western Regional Climate Center 2015). East Glacier Park averages 71 cm (28 in) annual precipitation and an average snowpack of 439 cm (173 in). At Marias Pass (Summit weather station), total average snowpack is 633 cm (249 in) with an average annual precipitation of 95.2 cm (37.5 in). Mean January low temperature ranges from -10.5°C (13.1°F) at East Glacier Park, to -12.5°C (9.5°F) at Valier, while the mean July high temperature ranges from 23.5° C (74.4 °F) at East Glacier Park to 27.2°C (81°F) at Valier. The Rocky Mountain Front of the Two Medicine Valley regularly receives Chinook winds during fall and winter months. Gusts can occur in excess of 100 mph but typically average 50 to 65 mph.

Summer precipitation largely occurs during late May and June, with occasional thunderstorms occurring during July and August. Fall precipitation can be variable. Freezing temperatures and snow, however, can occur during all months. Average spring snowmelt dates, or onset of spring runoff pulse, occurs on average in the general region 20 days earlier than historical averages (USGCC 2009). Freeze free seasons are extending in the region on average by 20 to 30 days (Pederson et al 2010), and temperature increases has been observed for all seasons during the last 30 years (NOAA 2013).

The summer of 2015 was the hottest summer on record for the state of Montana with the average temperature being 4 degrees above the median temperature recorded for the base period of 1910-2000 (NOAA 2015). Upward temperature trends are statistically significant for all seasons in the northern Great Plains (NOAA 2013), affecting the eastern half of the Two Medicine watershed, as well as increasing temperature trends (Pederson et al 2010) in the Northern Rocky Mountains of the western third of the watershed. During 2016, there was a significant winter precipitation deficit due to the El Nino cycle from January to April, with only 5.5 in precipitation during these months. Spring and summer rains occurred from May to July however total year to date precipitation for 2016 were only 34% of normal averages.

Water and Hydrology

The Two Medicine watershed is fed from annual snowpack originating in the Two Medicine Valley of Glacier National Park and the Continental Divide of the Lewis and Clark National Forest. Bedrock of Cretaceous-age Blackleaf and Kootenai Formations occur at the western boundary of the watershed, are permeable and recharged by snowmelt and precipitation. Discharge to area streams is primarily from unconsolidated deposit aquifers in the western third of the watershed. Bedrock aquifers do not contribute significantly to the area watershed.

Numerous springs occur in areas of contact between bedrock and unconsolidated deposits and are the principal groundwater recharge source in the watershed. Coarse-grained, unconsolidated deposits of alluvium gravel terraces and pediments, till and outwash occurring above bedrock are local rural sources of potable water use (Cannon 1996), occurring above permeable sandstone bedrock of the Virgelle Formation and the lower part of the Two Medicine Formation in the eastern sections of the Reservation. Aquifers occur at much greater depths beneath the Bear Paw and Two Medicine Formations, in the south-central and southeastern third of the Reservation.

Water from the Two Medicine Formation typically has large concentrations of solids; water is more mineralized in deeply buried sandstone aquifers than near surface sandstone aquifers within the Disturbed Belt (Cannon 1996). Water influenced by area marine shales of the Marias River Formation, upper part of the Two Medicine Formation and the Bear Paw Shale and Saint Mary Formations is not suitable for livestock or domestic use. Alluvium gravel beds within or beneath till, or gravel in terraces and pediments, and glacial outwash are used as sources of domestic water supply. Unconsolidated deposits are the only sources of drinkable domestic water in areas of marine shale deposits or sedimentary mudstones.

Lakes of the Two Medicine Watershed include Big Spring Lake, Dog Gun Lake, Minnie White Horse Lake, Little Goose Lake, Mitten Lake, Buffalo Lakes and Cooper and Kiyo Crags Lake of the Lewis and Clark National Forest. There are several, smaller groundwater-fed unnamed lakes in the western portion of the watershed. Major streams and tributaries, originating near the Continental Divide include Summit Creek, Deep Creek, Railroad Creek, Midvale Creek, South Fork of the Two Medicine River, Little Badger Creek and Badger Creek. Badger Creek joins the Two Medicine River north of Kipps Coulee. The confluence of the Two Medicine River and Birch Creek occurs south of Buffalo Ridge, near the Reservation boundary. The Two Medicine joins the Marias River near the borders of Glacier, Pondera and Toole counties, southeast of the Reservation.

Area lakes occurring on the National Forest and BIA Trust sections of the Reservation, as well as Upper and Two Medicine lakes of Glacier National Park and the Two Medicine Reservoir, are used for sport fishing by area residents, tourists and sports fisherman. These lakes contain exceptional, healthy fisheries of cutthroat, brook and rainbow trout. There are numerous groundwater-fed ponds and small lakes as well as dense concentrations of prairie potholes, depressions, marshes and wet meadows at a range of elevations within the western third of the watershed.

Midvale Creek served as the principal water supply for the town of East Glacier until 2011, and still serves as a backup water supply. The Two Medicine Reservoir (Lower Two Medicine Lake) was constructed during the 1930s. The dam was breached by the Flood Event of 1964, resulting in tragic loss of life along the river corridor of the Reservation. The dam was reconstructed and completed in 1966. The Two Medicine Reservoir serves as the principal water supply for the towns of Browning and East Glacier Park since January 2011. Securing the water treatment plant in this newly constructed facility with a 20 foot high fence and surveillance cameras is a top watershed priority to ensure safety and enforce regulations of the Reservation’s main water supply. A discussion and report on securing this facility can be found in the Two Medicine Watershed Report. The Two Medicine Canal, in the central portion of the watershed is secured by fencing to prevent accidents and safety concerns. The canal originates approximately 2 miles west of Highway 89.

Flora and Vegetation

The East Glacier Potholes and Tribal Bison Preserve, just north of East Glacier Park, have previously been described as one of the best opportunities to protect and conserve high quality and diverse range of glacial potholes and associated wetlands in the United States (Lesica 1990). High quality, active beaver colonies and beaver influenced riparian areas and marshes are common along Badger Creek, Little Badger Creek, Deep Creek, and Railroad Creek near the boundary of the Lewis and Clark National Forest. Active beaver colonies are also found in area groundwater ponds, small lakes, streams and rivers within the Carbonate Front and Foothills region near the Two Medicine Valley of Glacier National Park. Near the Continental Divide, willow dominated communities and mixed black cottonwood (Populus balsamnifera) and mixed coniferous forests occur along the Two Medicine River and the South Fork of the Two Medicine and its tributaries.

Wet meadows, fens and marshes occur in association with streams and groundwater springs and contain high wetland plant species richness. Aspen forested potholes occur at a range of elevations in the western third of the watershed. Camas, of cultural significance to the Tribe, is frequent in wet meadows, mesic grasslands and mesic aspen forest in headwater areas. Two Medicine area wetlands contain a wide range of wetland plant species due to their variable water chemistries, landscape position and occurrence within a largely natural landscape. Aspen and cottonwood forested wetlands, kettle ponds, potholes and small lakes are found the western and central portion of the watershed at a range of elevations. Wetlands occurring in association with the Carbonate Front in the southwestern portion of the watershed frequently contain from 60 to 90 plant taxa. Further to the east, potholes, open, closed and saline depressions are common and contain alkaline and saline tolerant taxa, many of which are important sources of forage to area waterfowl. Saline depressions are especially prevalent in the central and eastern sections of the watershed and are critical to early spring arriving migratory waterfowl and shorebirds.

Area forests include extensive stands of mature Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), subalpine fir-spruce (Abies lasiocarpa-Pinus engelmannii) and occasional stands of limber pine (Pinus flexilis) near river breaks and ridgelines. Whitebark pine (Pinus

albicaulis), a Species of Concern, occurs in the Badger Two Medicine area of the Lewis and Clark Forest and western edge of Two Medicine Valley of Glacier National Park. Throughout the watershed, good quality examples of fescue grassland at a range of elevations, as well as mixed grass prairie occur on tribal, allotted and fee lands. Sparsely vegetated badlands and cliff bands are found along the main Two Medicine River in the central and eastern portions of the watershed.

Below Two Medicine Falls, approximately 3 miles below the Two Medicine Dam, the river corridor provides excellent cutthroat and rainbow trout fishery and is a major travel corridor for area wildlife. This section of the river is largely bordered by mature stands of Douglas-fir and lodgepole pine on steep to very steep (>70%) slopes of exposed, marine-derived shales. On steep south facing slopes, Juniperus horizontalis occurs in association with conifer stands or alone with very sparse forb/grass cover. On steep north facing slopes, mesic or dry understory is associated with either Douglas-fir or lodgepole pine, and includes in some sites, high lichen moss or lichen cover with sparse cover of graminoids.

In the central and eastern portions of the Badger Creek and the Two Medicine River are some of the highest quality cottonwood dominated river floodplain communities known in northern Montana. Area geology includes exposed marine shales that are overlain by mostly sandstone and some limestone, near the Carbonate Front. Cottonwood stands include pure stands of black cottonwood (Populus balsaminifera) in the western third and primarily pure stands of narrowleaf cottonwood (Populus angustifolia) in the central and eastern portions of the watershed. Mature mixed black cottonwood (Populus balsamnifera) and narrowleaf cottonwood (Populus angustifolia) are found in the southwestern portion of the watershed.

Stands of coyote willow (Salix exigua) and peachleaf willow (Salix amygdaloides) occur on point bars and alluvial terraces. Riparian communities dominated by cultural species such as ghost lariat (Clematis ligusticifolia) and silverberry (Elaeagnus commutata) occur on cobbles and gravels on level or steep terraces adjacent to the river channel. Near the Two Medicine Canal, river slough wetlands and diverse understory vegetation in association narrowleaf cottonwood can be found. Primary wildlife food sources, such as serviceberry (Amelanchier alnifolia) and chokecherry (Prunus virginiana) are abundant in cottonwood understory.

Overall ecological condition of riparian vegetation along the Two Medicine in the western and eastern portion of the watershed is good to excellent, despite grazing and serious knapweed (Centaurea stoebe) infestations in some sections. Intensive surveys for Russian olive (Elaeagnus angustifolia), as well as salt cedar (Tamarix chinensis), which has been recently found in the Missouri Breaks Region, 150 miles east of the Reservation, are needed along the river corridor for early detection and eradication during future monitoring work.

Fauna

Two Medicine Watershed wetlands and riparian areas are crucial to population maintenance, migratory patterns and dispersal of all wildlife species known to occur in the Northern Rocky Mountain ecosystem, as well as fauna restricted to the Northwestern Great Plains region. Reservation lands and the Badger-Two Medicine area of the Lewis and Clark National Forest are

well documented as critical spring and fall feeding areas for grizzly bears, which rely on the abundance of spring forage and roots found in the area.

Notably, this area of the watershed contains abundant populations of cous root (Lomatium cous), only marginally found in the southwestern extremity of Glacier National Park. This cultural species is an extremely important food source to grizzly bears during spring and fall months. Notably, area aspen forests and grasslands contain shrub understories or grassland shrub stands of serviceberry (Amelanchier alnifolia) and chokecherry (Prunus virginiana), important to late summer and fall diets of black and grizzly bears. Herbaceous communities in mesic aspen forest contain high cover of desirable bear forage such as sweetroot (Osmorhiza occidentalis) and cow parsnip (Heracleum lanatum). Narrowleaf cottonwood (Populus angustifolia) communities along the river and its tributaries often contain high cover of serviceberry and chokecherry.

Protected avian species, such as trumpeter swan and golden and bald eagles, are frequently seen in area wetlands and the river and tributary corridors. Many other avian Species of Concern that are largely found in wetland habitats such as mountain plover, long billed curlews and avocets are commonly seen in saline and alkaline potholes and depressions. Other migratory and summer resident waterfowl, such as sandhill crane, tundra swan, snow geese, canvas back, northern shoveler, pintails, blue winged teal, green teal, mallard and wood duck utilize area high quality wetland habitat for summer nesting.

Aspen and cottonwood forests support dozens of additional nesting species, including numerous species of neo-migratory songbirds and raptors. Area lakes and streams contain superb fisheries as well as providing habitat to amphibians and rare mollusks. Area flora and intact native vegetation of the Reservation, Lewis and Clark NF and Glacier National Park contain remarkable insect diversity and an abundance of healthy populations of bees, bumblebees, butterflies and moths, important in maintaining area flora and bird populations, as well as supporting local commercial honey production.

The Two Medicine watershed contains critical grizzly habitat as well as healthy populations of black bear, badger, moose, white-tail deer, elk, fox, coyote, fisher, beaver, muskrat, gray wolf, lynx, mountain lion and wolverine. Columbian ground squirrels, pine squirrels, snowshoe hare and weasels are also common. The Tribal Bison Herd currently consists of over 300 head, with calves born each spring and is managed within the Two Medicine watershed. Antelope, red fox, swift fox, white tail deer, bobcat, jack rabbit, porcupines, raccoon, skunk, prairie dogs and ground squirrels constitute the major fauna along the eastern edge of the watershed. This area is one of the last places in the lower 48 where all northern Great Plains and Northern Rocky Mountain wildlife still occur, due to high water quality and habitat and connectivity to protected areas.

Recent Fire History of Two Medicine Watershed

Three major wildfires occurred within the Two Medicine watershed during the past 13 years: the Pike Creek Fire (1998), Skyland Fire (2007), and Spotted Eagle Fire (2015). In 2015, the Spotted Eagle Fire burned over 50,000 acres of Reservation and adjacent National Forest lands

and forced the evacuation of Heart Butte and rural ranches and residences 9 miles to the north of Heart Butte. The fire burned a variety of forest types, including lodgepole, Douglas fir, subalpine-fir-spruce, limber pine woodlands, aspen parkland, grasslands and high elevation meadows and scree slopes. Some riparian habitat burned in the headwater areas of Badger Creek, consisting of mostly mixed stands of willow-cottonwood or cottonwood-conifer riparian forest types.

Land Use

Major economic drivers of the watershed include summer tourism, ranching and farming. Local fishing, hunting, hay and livestock production are sources of sustenance and income to area Tribal residents. Crop production consists of winter wheat rotated with dryland peas and chickpeas or alfalfa. Both dry land and irrigated crop production occur in the central and eastern portions of the watershed on fee lands. Native hay, alfalfa and to a lesser extent, sainfoin, is also grown for livestock hay production. Apiculture (honey production) occurs throughout the central and eastern portions of the watershed where alfalfa is commonly grown. BIA Trust sections are leased for summer cattle grazing. Locally owned cattle and horses use fee, allotted and trust sections for grazing.

The Two Medicine Valley of Glacier National Park receives heavy tourist traffic from June to early September, with increasing “shoulder-season” traffic occurring during the spring and fall months. Area residents utilize lakes and rivers for sports fishing throughout the year. Some sports and recreation traffic occurs in Lewis and Clark National Forest including hunting, fishing, hiking and backcountry camping.

Oil and gas production have occurred in the eastern portion of the watershed east of Valier Road (Cutbank Sands Unit) near the Reservation Boundary and at widely scattered locations in the western and central portions of the watershed. More recently, exploratory oil and gas production have occurred in the western third near East Glacier Park.

Monitoring Study Objectives

1) Collect baseline data of wetland ecological condition in the Birch Creek watershed, including water quality data, macro-invertebrate and vegetation sampling, to assess overall condition and function.

2) Determine impacts to wetland condition and water quality.3) Examine relationships between disturbances and wetland condition. 4) Utilize results to determine wetlands for protection, conservation and restoration.

Wetland Assessment Methodology

The Tribal Wetlands program personnel used the Montana Natural Heritage Program’s Ecological Integrity Assessment methodology (MNHP 2015). The protocol uses three levels of analysis: 1) Landscape analysis; 2) Qualitative Rapid Field Assessment and 3) Intensive Vegetation and Disturbance Indicator Assessments.

Site Selection

Sites were selected by probabilistic random sampling across the Two Medicine watershed to capture a range of wetland ecosystem types on fee, allotted and tribal land, in a range of eco-regions (Foothill grassland, Glaciated Plains, Carbonate Front, Front Foothill) occurring in the watershed. A total of 240 wetland sites were selected for sampling with the base sample of 30 wetlands for the monitoring study (oversample of 210 wetlands). See map (Figure 1) for location of 2016 wetland monitoring sites.

Field Data Collection

Two Medicine wetland assessments were conducted during June to early August 2016. A total of 30 wetland sites were assessed using the Level 2 Rapid Assessment Method and a subset of 10 of the 30 sites were assessed using the Level 3 Intensive method. GPS and photo points were taken at each wetland assessment area, of each soil profile at all 30 sites and of the vegetation plot in the 10 Level 3 sites. One wetland soil core was collected per site to examine wetland soil layer features. One wetland vegetation quadrat was established in the 10 Level 3 sites to measure structure, canopy cover and composition of wetland vegetation, using methodology described in the MNHP protocol.

Data Analysis and Quality Assurance/Quality Control (QA/QC) Standards

Data was entered into a MS Access database (2007) for analysis. Backup data was stored on external hard drives and jump drives. A subset of 8 wetlands were re-examined during August 2016 for QA/QC procedures and to re-examine data collected.

Floristic Quality Assessments (FQI) scores were assigned by calculating the coefficients of conservatism values (C values) for all plant taxa occurring in Level 3 vegetation plots. The C values range in score from 0-1 (exotics) to 10 (native taxa w/ high specificity) (Pipp 2016). Overall wetland condition scores were calculated for each metric (Landscape, Biophysical and Biological) per site to arrive at an overall wetland condition score per site. Wetland condition scores and data were evaluated per wetland ecosystem type, landownership and eco-region location.

Results

Landscape, Physiochemical, Hydrologic and Vegetation metrics and disturbances were calculated to arrive at an overall mean EIA (Ecological Integrity Assessment) score for each wetland type. Total mean EIA scores per wetland system type are shown in Table 1.

Table 1: Mean Final Wetland EIA scores in the Two Medicine Watershed

Wetland Ecological System No. Mean

Great Plains Prairie Pothole 4 86.0

Western Great Plains Closed Depression Wetland 2 67.5

Western Great Plains Open Freshwater Depression Wetland

3 86.5

Northern Rocky Mountain Forested Pothole 3 85.5

Great Plains Riparian Floodplain 5 67.5

Rocky Mountain Riparian Shrubland 8 84.0

Great Plains Saline Depression 2 62.5

N. Rocky Mountain Montane Fen 1 85.0

N. Rocky Mountain Wet Meadow 2 82.5

Western North American Marsh 1 67.5

Soils

Wetland soils were highly variable in all 30 assessed wetlands. Histic soils were encountered in the rich fen and floating peat mat (47 cm deep) associated with a larger, higher elevation, groundwater fed forested pothole. Wet meadow soils encountered in the RM foothills were histic epipedon (35 cm) overlying clay layer. Foothill potholes and depressions exhibit minimal organic layers and are composed of silty-clays overlying clays with varying redox concentrations and depletions in lower layers. One higher elevation pothole on Two Medicine Ridge contained pure clay with high glacial till content. GP Riparian floodplain soils are typically sands to sandy loams over alluvial gravel or large cobble. River slough wetlands and beaver influenced riparian shrublands typically have a few centimeters of mucky peat overlying silty clays or clays. High depletion concentrations were encountered with depressional wetlands and marshes with permanent to semi-permanent saturation.

Physiochemical and Landscape Scores

Similar to other Reservation watershed results, Level 2 hydrologic metrics (hydroperiod, alteration and connectivity) of the Two Medicine Watershed scored highest of all metrics measured, followed by physiochemical (water quality, soil surface integrity) and landscape metrics (connectivity, buffer width, length, condition, soils, trash). All sample sites scored high

in surface water connectivity. Fifty-four percent of assessed wetlands had excellent soil surface integrity scores (1) with remaining scores that ranked good (2) due to light to moderate grazing impacts.

Livestock grazing was the most frequent disturbance within wetlands and upland buffers. Forty-three percent of assessed wetlands had moderate (2) grazing scope and impact scores within wetland AA and the upland buffer zone. Overall buffer condition metric scored as good to excellent. Buffer condition scores were lower in NWGP riparian floodplain sites due to prevalence of spotted knapweed and scope and intensity of grazing impacts. The second most common disturbance within the wetland AA was proximity to secondary roads (dirt roads) or seldom travelled two-tracks. Impacts due to energy development occurred within one AA wetland buffer and within 100-200 meters of two additional assessed wetlands. One wetland contained refuse (old car) within the AA and one additional assessed wetland contained refuse within 100 m buffer. A significant amount of depressional wetland acreage in the eastern third of the watershed is impacted by agricultural production without existing native upland buffers. Agricultural impacted wetlands in this portion of the watershed were not assessed.

Vegetation Metric Scores

Seventy-four percent of the 30 assessed wetlands contain 99% or greater native wetland vegetation, while 17% contained 95-95% natives and 9% contained less than 80-94 percent native vegetation. Forty-six percent of sampled wetlands contained noxious weed species with cover values (<5%), most frequently, Canada thistle (Cirsium arvense) followed by spotted knapweed (Centaurea stoebe). Spotted knapweed infestations occurred primarily in floodplain shrublands and open cottonwood forest on alluvial terraces with sharply drained sandy-loams and cobble. Two assessed riparian shrublands contain (< 5%) cover of hounds tongue (Cynoglossum officinale). The invasive grass meadow foxtail (Alopecurus pratensis) was the most common invasive graminoid in assessed depressional wetlands, followed by common timothy (Phleum pratense) and Kentucky bluegrass (Poa pratensis), found in association with grazed riparian shrublands. We did not encounter any populations of poison water hemlock (Conium maculatum), Russian olive (Elaeagnus angustifolia) or salt cedar (Tamarix sp) during field work in the Two Medicine watershed. However, portions of the eastern watershed should be more intensively surveyed for these noxious species during future monitoring work.

Six wetland plant community types were associated with the Rich fen. On average, beaver influenced riparian shrublands, foothill wet meadows and GP spring fed-marshes contained 5 distinct plant communities. NW Great Plain Riparian Floodplain forest contained an average of 3 communities however river slough wetlands associated with the Two Medicine river contained 6 plant communities. Aspen potholes contained an average of 3 plant communities. Groundwater fed Great Plains prairie potholes contained 3-5 wetland plant communities but some occur as narrow bands of vegetation along the drawdown margin. Great Plains saline and open depressions within the eastern portion of the watershed contained on average 2-3 wetland plant communities.

EIA Scores

Two Medicine (2016) EIA Scores are comparable to other Reservation watershed EIA scores (Milk-2013, Saint Mary-2014, Cutbank-2015, Birch Creek-2014-15) per wetland ecosystem type. On average, wetlands occurring in the eastern section of the TM watershed (Glaciated Plains) had lower EIA scores than similar wetlands occurring in the western and central portions of the watershed (Foothill Grassland, Carbonate Front, Front Foothill).

During 5 years of wetland assessments on the Blackfeet Reservation, a total of 130 wetlands were assessed. Total averaged mean average EIA Scores per wetland ecosystem type in the 5 watersheds are shown in Table 2. Total mean wetland EIA score for Blackfeet Reservation wetlands is 81.0

Table 2: Total Mean Wetland EIA scores in 5 Watersheds of the Blackfeet Reservation

Wetland Ecological System No. Mean

Great Plains Prairie Pothole 32 81.0

Western Great Plains Closed Depression Wetland 12 77.0

Western Great Plains Open Freshwater Depression Wetland

14 85.5

Northern Rocky Mountain Forested Pothole 10 82.0

Great Plains Riparian Floodplain 11 73.3

Rocky Mountain Riparian Shrubland 29 83.0

Great Plains Saline Depression 5 72.0

N. Rocky Mountain Montane Fen 4 87.0

N. Rocky Mountain Wet Meadow 8 88.0

Western North American Marsh 4 82.5

Isolated Spring 1 78.5

Level 3 Intensive Vegetation Results

Level 3 wetland vegetation assessments were conducted on 4 Allotted, 4 Tribal and 2 Fee landownerships within all representative eco-regions within the watershed: Carbonate Front (3), Foothills (5) and NW Great Plains (2). Mean Floristic Quality Assessment scores were calculated for all Level 3 assessment sites per wetland ecosystem type. FQI scores range from 0 (for noxious weeds) to 10 (taxa that exhibit a very narrow range of ecological tolerance and found in areas with very narrow habitat requirements). Results are shown in Table 3.

The Floristic Quality Index (FQI) is calculated using the following formula:

Where is the mean C-value and N is the number of native species within the entire plot.

The FQI was calculated to a score that includes non-native species by the following:

Table 2: Mean FQI scores for ten sites in the Two Medicine Watershed 2016

Wetland Ecological System No. Mean Min Max

Great Plains Prairie Pothole 3 27.8 32.2 44.5

Great Plains Open Freshwater Depression 1 37.8 37.8

Great Plains Saline Depression 1 46.5 - 46.5

Rocky Mountain Subalpine-Montane Riparian Shrubland 4 42.2 40.5 44.1

Rocky Mountain Montane Fen 1 59.4 59.4

Riparian shrublands associated with beaver ponds that were assessed in the Two Medicine watershed had the second highest FQI mean scores in all riparian shrublands assessed in reservation watersheds (Milk> TM> Birch Creek> Saint Mary> Cutbank). The cottonwood riparian forest wetland with the greatest species richness occurred within the Carbonate Front (65 taxa). Dominant communities in this riparian area included black cottonwood/redosier dogwood (Populus balsamifera/Cornus sericea), cottonwood/wild rose (Populus balsamnifera/Rosa acicularis) and Booth’s willow/Mesic Forbs (Salix boothii/Mesic Forbs). In comparison, narrowleaf cottonwood communities in the Glaciated Plains eco-region contained 25 taxa and were composed of cottonwood/ western snowberry (Populus angustifolia/Symphoricarpos occidentalis), silverberry (Elaeagnus commutata) and coyote willow (Salix exigua) communities.

Beaver influenced riparian shrublands contained on average 41 plant taxa (r 34-55). The most frequent woody plant communities in association with beaver ponds and riparian streams assessed are Drummond’s willow/ Northwest Territory sedge (Salix drummondiana/Carex utriculata) and Booth’s willow/ Mesic Forbs or Booth’s willow/ Northwest Territory sedge. The most common emergent community in beaver influenced wetlands is Northwest Territory sedge/ water sedge (Carex utriculata/Carex aquatilis), followed by small patch communities dominated by tall mannagrass (Glyceria grandis) or boreal mannagrass (G. borealis). The most common open water emergent communities in beaver ponds are white water crowfoot (Ranunculus aquatilis) and tuberous pondweed (Potamogeton pectinatus).

The Rocky Mountain foothill fen located near the Carbonate Front contained a total of 47 taxa within vegetation plots and had similar FQI score to the fen assessed in the Milk watershed. Woody communities within the fen were dominated by Salix boothii and Salix drummondiana, Betula sp/water sedge (Mixed Betula pumila and Betula occidentalis/ Carex aquatilis-Carex lasiocarpa) with high bryophyte cover and Booth’s willow-sage leaf willow/Northwest Territory sedge (Salix-boothii-Salix candida/Carex utriculata). Herbaceous communities included Carex aquatilis, Carex lasiocarpa, Carex utriculata, and small patch Eleocharis quinqueflora.

Groundwater influenced Great Plains prairie potholes in the Foothill eco-region of Two Medicine contain on average 23 taxa (r 11-32) and had the highest mean FQI scores of all Reservation watersheds (TM>Saint Mary>Birch Creek>Milk). Open and saline depressions also had higher FQI scores to similar wetlands in other watersheds. Open and saline depressions assessed in the Two Medicine Glaciated Plains eco-region contained 11-19 taxa. The most common emergent communities in all depressional wetlands assessed were hardstem bulrush (Schoenoplectus acutus) and common spikerush (Eleocharis palustris).

Application of Results

During wetland assessment field work, we identified several wetlands that could be potentially protected, conserved and restored on allotted and tribal lands. Three sites were selected for conservation/protection and/or restoration. Additionally, we located and assessed a range of reference quality wetlands including NRM Riparian Shrubland, aspen forested potholes, upper montane potholes (kettleponds), fen and floating peat mats within forested potholes and several locations of black cottonwood, mixed cottonwood and narrowleaf cottonwood GP Riparian floodplain. These high quality sites on the Blackfeet reservation could potentially be utilized as restoration reference sites.

We also identified a significant amount of Fee Land wetland acreage within the eastern section of the Two Medicine watershed that are primary candidates for wetland restoration and wildlife habitat improvement. Cooperative efforts and incentives for landowners are needed in order to restore wetland condition and maintain wetland functionality in the driest region of the watershed that are vulnerable to loss due to climate change and land uses.

Floristic Quality Assessment scores are useful in determining wetlands protection and restoration as well as identifying individual wetlands and wetlands areas within eco-regions that contain greater species richness or overall ecological quality. Comparing FQI and EIA scores and results between and among the Reservation’s watersheds is useful to identify future monitoring work and develop specific management goals for the wetlands of the Blackfeet Reservation.

References

Flora of North America, (FNA). 1993-2011. Published volumes and online treatments. Oxford University Press. (London and New York).

Hitchcock CL and Cronquist A. 1987. Flora of the Pacific Northwest. University of Washington Press. Seattle (WA) 343 p. ISBN 0-295-95273

Lesica P. 2012. Montana Vascular Plants. Britt Press. Fort Worth, Texas. 771 p.

Lesica P and S Shelly. 1988. The vegetation and flora of glaciated prairie potholes on the Blackfeet Indian Reservation, Montana. Progress Report. The Nature Conservancy Montana/Wyoming Field Office. Helena, MT. 19 p.

Lesica P. 1990. East Glacier Prairie Pothole Preserve Design. Report prepared for the Blackfeet Tribe. Unpublished report. 11 pp.

NOAA National Centers for Environmental Information, State of the Climate: Global Analysis for Annual 2015, published online January 2016, retrieved on February 3, 2016 fromhttp://www.ncdc.noaa.gov/sotc/global/201513.

National Oceanic and Atmospheric Administration (NOAA). 2013. Regional Climate Trends and Scenarios for the US National Climate Assessment. Part 4 Climate of the US Great Plains. US Department of Commerce, Washington DC, 91 pp.

Pederson GT, Graumlich L, Fagre D, Kipfer T, Muhlfeld C.. 2010. A century of climate and ecosystem change in Western Montana: what do temperature trends portend? Climate Change 98: 133-154.

Pipp, A. 2016. Coefficients of Conservatism for the Flora of Montana. Part 1. Montana Natural Heritage Program. Helena, MT. Prepared for the MT Dept. of Environmental Quality. 75 p.

Montana Natural Heritage Program. 2015. Wetland Assessment Protocol. Helena, MT. 55 pages.

US Global Change Research Program. Karl T, Melillo JM, and Peterson TC (editors). 2009. Global Climate Change Impacts in the United States. Cambridge University Press. 189 p.

Western Regional Climate Center. 2015. (URL: http://www.wrcc.dri.edu/.)