Monitoring Wetland Ecological Condition of Birch Creek Section of theTwo Medicine Watershed, Blackfeet Reservation, Montana

Prepared for the US Environmental Protection Agency, Region 8, Denver, Colorado

Blackfeet Environmental Office, Blackfeet Nation, Browning, Montana

Tara Luna, Mary Clare Weatherwax, and George Running Wolf, III

January 2016

This page intentionally left blank

Birch Creek Watershed Wetland Monitoring and Assessment (2014-2015)

Monitoring Project Overview

The Blackfeet Tribe has adopted a “no-net loss of wetlands” policy in accordance with Tribal and Federal regulatory standards. The monitoring results from this project will be utilized to further develop the Blackfeet Tribe’s Wetlands Program in accordance with the guidelines found in the US Environmental Protection Agency’s (EPA’s) Core Elements Framework (CEF).

These include developing wetland regulatory standards; wetland water quality and condition monitoring and assessment; wetland restoration and protection; and water quality standards for wetlands. During 2014-2015, twenty-one wetlands were assessed in the Birch Creek watershed.

The Birch Creek Watershed Area

Geology and Soils

The disturbed belt of the Rocky Mountain Front south of Glacier National Park is composed primarily of Cambrian to Cretaceous age limestone bedrock, with youngest age rock exposed east of the Lewis Overthrust. Mountain peak geology consists of the Saint Mary, Horsethief Sandstone and Two Medicine Formations. Landslide deposits occur beneath mountain summits including Heart Butte Mountain on the Reservation. Glacial till from Piedmont glaciers occurs along the Rocky Mountain Front and foothills above Cretaceous age sedimentary bedrock. Till deposits from the Continental Ice sheet predominate the eastern section of Birch Creek. Pleistocene deposits of gravels, cobbles and occasionally sand, were deposited in a broad swath from Blacktail Creek to just west of Alkali Lake. Pediment and terrace gravels were deposited in the southern and eastern portions of the drainage, with older Pliocene gravel deposits found near summit ridges. Alluviums and gravels occur within the Birch Creek floodplain (Cannon 1996).

Wetland soils in the Birch Creek area typically have an organic layer averaging 26-60 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 predominate in floodplain wetlands. Histic soil peat layers range from 10 to 20 cm deep overlying limestone bedrock in forested spring systems near Swift Dam (Sheep Creek), just west of the study area.

Climate

From 1911 to 2010, annual average precipitation averages 41.0 cm (16.0 in) at Heart Butte to 31.4 cm (12.4 in) at Valier, with an average annual snowpack of 160 cm (63.2 in) at Heart Butte to 83.5 cm (33.2 in) at Valier (Western Regional Climate Center 2015). Insufficient local temperature data were available for Swift Dam and Heart Butte stations. However, mean January low temperature ranges from -10.5°C (13.1°F) at East Glacier, 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, to

1

27.2°C (81°F) at Valier. Current prevailing climate is often drier south of Marias Pass, compared to mountain valleys north of the Birch Creek watershed.

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 20 to 30 days (Pederson et al 2010), and temperature increase has been observed for all seasons for 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). Since 1990 there have been several years with high frequency of extreme precipitation events in the Great Plains Region, one affecting the Reservation occurred in October-November of 2007. Upward temperature trends are statistically significant for all seasons in the northern Great Plains (NOAA 2013).

Water and Hydrology

The Birch Creek watershed is fed from annual snowpack originating in the Lewis and Clark National Forest near the Continental Divide. Aquifer recharge occurs in saturated unconsolidated deposits overlying the Saint Mary Formation, Horsethief, Bearpaw and Two Medicine Formations. Bedrock of Cretaceous-age Blackleaf and Kootenai Formations occur at the southwestern boundary of Birch Creek, near headwater streams, influencing water chemistry of ground-water fed streams, lakes and ponds on the east facing slope of Major Steele Backbone.

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 impermeable bedrock layers. Aquifers occur at much greater depths beneath the Bear Paw and Two Medicine Formations, in the south-central and southeastern third of the Reservation.

Birch Creek is the southeastern boundary of the Reservation and flows into the Two Medicine River in Pondera County just above where Two Medicine joins with Cut Bank Creek to form the Marias River. Blacktail Creek, south of the town of Heart Butte, flows northeast and joins Birch Creek near Birch Creek Flats. Whitetail Creek flows north out of Heart Butte and joins Badger Creek which then flows into the Two Medicine River. Four Horns Lake, Green and Horn Lake are major recreational lakes for area residents and sports fishermen. Alkali Lake is an important wildlife conservation area that supports local populations of piping plover. Smaller, glacially carved, groundwater fed ponds and lakes occur on the western edge of the Reservation near the Lewis and Clark National Forest boundary and in the vicinity of Heart Butte. Smaller lakes are also frequently used by Heart Butte residents.

Flora and Vegetation

Wetland and riparian flora and vegetation communities in the Birch Creek watershed are diverse and include occurrences of rare flora, culturally important flora and more common

2

calciophilic wetland species locally found in the Carbonate Rocky Mountain Front. Forested potholes or kettle ponds, surrounded by aspen and cottonwood forests, occur in high density southwest of Heart Butte.

The Blacktail Bench wetlands area has been noted as one of the last best remaining examples of aspen wetlands in the western United States, which typically contain a forested wetland fringe, emergent and submergent communities and in some instances, occurrences of rare species (Lesica and Shelly 1988). Beaver influenced riparian areas and marshes are common in the vicinity of Heart Butte and Swift Dam. High density concentrations of prairie potholes and open and closed depressions, found within fescue prairie, are south and east of Heart Butte. Blacktail, Whitetail and Birch Creeks support black cottonwood (Populus balsamifera L. ssp. trichocarpa) and narrowleaf cottonwood (Populus angustifolia) dominated forests with understory willow (Salix spp.) communities. These riparian communities are in excellent condition. Saline and alkaline influenced wetlands are common in the plains and along the eastern edge of the Birch Creek watershed.

Birch Creek 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. Near the western boundary of Birch Creek and its tributaries, calciophilic wetland species can be found in springs and wetlands influenced by limestone bedrock. The area also contains diverse upland flora and forested ecosystems, including extensive limber pine (Pinus flexilis) woodlands and forests. Excellent condition prairie containing numerous potholes is found near Heart Butte, while forested potholes surrounded by aspen and cottonwood are found west and southwest of Heart Butte.

Fauna

Reservation 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 which is found in the eastern section of Birch Creek watershed near Valier. The Lewis and Clark National Forest is west of the Reservation and contains grizzly bear populations. Elk, moose, deer, red fox, coyote and smaller mammals are common in the Birch Creek watershed.

Reservation lands and the National Forest east of the Continental Divide 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. Extensive good condition woodlands of Limber pine (Pinus flexilis) also provide seed crops to resident grizzly bear populations and other wildlife. This five-needle pine produces relatively large seeds and is an important substitute to decimated whitebark pine (Pinus albicaulis) populations occurring at higher elevations on the National Forest and Glacier National Park.

3

Whitebark pine has recently been listed as a Montana Species of Concern and a Candidate Species under the federal Endangered Species Act. It was an important fall food source to area grizzly bear populations however, Northern Rocky Mountain populations have succumbed to blister rust disease (exceeding >95% mortality rate) in recent years. Consequently, other fall and spring food sources associated with the range of habitats in the Birch Creek watershed are important for wildlife conservation, including the wetland and riparian areas, which are used for travel and migratory corridors.

Antelope, jack rabbit, prairie dogs and ground squirrels constitute the major fauna along the eastern edge of the watershed near Alkali Lake. Threatened piping plover, as well as numerous species of shorebirds, raptors and waterfowl, are common in wetlands within the prairie potholes and the Alkali Lake area. Alkaline and saline wetlands are common on the eastern edge of the Reservation watershed. The Heart Butte area is locally well known for supporting numerous golden eagles, due to an abundance of food sources. Birch Creek commonly contains pairs of bald eagles. Area lakes support Species of Concern such as white pelicans and common loons while alkaline and saline wetlands can contain avocets and other Species of Concern. The watershed’s numerous potholes are important for migratory and resident waterfowl, shorebirds and numerous species of songbirds. Saline and highly alkaline wetlands are important for early arriving migratory species, because these wetlands become ice-free earlier in the season that other freshwater wetlands.

Recent Fire History of Birch Creek Watershed

Three major wildfires occurred within the Birch Creek/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. The fire burned a variety of forest types, including lodgepole, Douglas fir, limber pine woodlands, aspen parkland, grasslands and high elevation meadows and scree slopes.

Land Use

The residents of the community of Heart Butte hold a wealth of information about Blackfeet traditional culture. Several rural residences and ranches occur along Birch Creek and its tributaries, the Birch Creek Canal, and at very isolated locations near the mountains. Land use in Birch Creek includes livestock grazing on native fescue prairie and forests and irrigated hay production along the Birch Creek Canal. Local fishing, hunting, hay and livestock production are sources of sustenance and income to area Tribal residents. Some sports and recreation traffic occurs in Lewis and Clark National Forest and the Heart Butte community, including hunting, fishing, hiking and camping. Ice fishing is a weekend activity for local and area sports fishermen during winter months, while sport fishing is locally popular during summer months. During recent years, visitation in Glacier National Park has exceeded an average of 1.5 million visitors annually. As a result, tourist traffic in the nearby Two Medicine Valley and community of East Glacier Park has increased in recent years. The Heart Butte community receives much less tourist visitation. However, the scenic Rocky Mountain Front in the Heart Butte and Badger

4

Two Medicine areas are tourist draws due to the spectacular scenery, wilderness appeal and recreational opportunities.

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.

Study Methodology

The Tribal Wetlands program personnel used the Montana Natural Heritage Program’s Ecological Integrity Assessment methodology (MNHP 2014). 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 Birch Creek watershed to capture a range of wetland ecosystem types in varying states of ecological condition. See map Figure 1.

Field Data Collection

Birch Creek wetland assessments were conducted during June/July/August of 2014 and 2015. Refresher training on wetland assessment protocol and plant identification was provided during June 2015. A total of 21 wetland sites were assessed using the Level 2 Rapid Assessment Method and a subset of 8 of the 21 sites were assessed using the Level 3 Intensive method. Original target coordinates were used whenever possible, although 3 sites were shifted within 60 m of the original target coordinates.

Two original targets were not assessed: 1) due to loss of wetland by erosion and 2) due to lack of evidence of former wetland functionality and may have been incorrectly mapped during previous mapping efforts. GPS and photo points were taken at each wetland assessment area and of the soil pit and vegetation plot. One wetland soil core was collected per site to examine wetland soil layer features at all sites. One wetland vegetation quadrat was established in the 8 Level 3 sites to measure structure, canopy cover and composition of wetland vegetation, using methodology described in the MNHP protocol.

Vegetation sampling and wetlands assessments included a range of wetland systems across the watershed, ranging from groundwater fed streams near the western boundary to groundwater fed forested potholes, prairie potholes and closed depressions in fescue prairie, to saline wetlands near the eastern edge of the watershed.

5

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.

Floristic Quality Assessments (FQI) scores were assigned by calculating the coefficients of conservatism values (C values) for all plant species occurring in plots. The C values range in score from 0-1 (exotics) to 10 (native taxa w/ high specificity) (Pipp 2015).

6

Figure 1.

7

Results

Twenty-one Level 2 assessments were conducted in the Birch Creek Watershed during 2014-2015. Landscape, Physiochemical, Hydrologic and Vegetation metrics and disturbances were calculated to arrive at an overall mean EIA score for each wetland type. Total mean scores per wetland system type are shown in Table 1.

Table 1: Mean Final EIA scores in the Birch Creek Watershed

Wetland Ecological System No. Mean

Great Plains Prairie Pothole 7 71

Western Great Plains Closed Depression Wetland 4 86

Western Great Plains Open Freshwater Depression Wetland

3 95.4

Northern Rocky Mountain Forested Pothole 1 84.5

Great Plains Riparian Floodplain 3 68.4

Rocky Mountain Riparian Shrubland 1 82.2

Great Plains Saline Depression 2 60.5

Physiochemical and Landscape Scores

Level 2 hydrologic metrics (hydroperiod, alteration and connectivity) had the highest score 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, while three sites exhibited hydrologic alterations or hydroperiods. One site along Birch Creek was severely eroded due to past flooding and was not assessed. Soil surface integrity scored lower than water quality, due to grazing disturbances.

Livestock grazing was the most frequent disturbance within wetlands and upland buffers. Scope and impact of livestock grazing in wetlands were low to moderate (10-25%) in all Assessment Area (AA) sites and low to moderate in surrounding 200 m upland buffers. However on tribal land, depressional wetlands scored higher than those on fee lands. Some closed depressions, open depressions and some potholes were found to be in near pristine condition on tribal lands. Seventy-five percent of sampled wetlands on tribal lands had minimal livestock impacts in the AA.

8

Wetlands occurring in proximity to the Birch Creek Canal were impacted by hydrologic alteration or influenced by canal seepage. Three wetlands that were assessed were greater than 200 m from paved or unpaved roads however the majority of sites were located within 100 m of less of secondary two-track roads or paved roads. Some wetlands occurring near paved roads however, near the mountains, were in excellent condition and often contained high species richness compared to depressional wetlands located in the eastern third of the watershed.

Vegetation Scores

Ninety five percent of wetlands contained native vegetation with cover values greater than 95 percent. However, 70% of sampled wetlands contained noxious weed species with cover values (<5%), most frequently, Canada thistle (Cirsium arvense) within the AA and spotted knapweed (Centaurea stoebe) in the upland buffer. The most common noxious species were Cirsium arvense in the AA and Centaurea stoebe (syn. C. maculosa) in the upland buffer. Invasive grass meadow foxtail (Alopecurus pratensis) was most common in wetlands containing standing water. Timothy (Phleum pratense) and Kentucky bluegrass (Poa pratensis) were found in association with temporary closed depressions that are no longer hydrologically functional. Stands of quackgrass (Elymus repens) were encountered at one riparian site.

Level 3 Intensive Vegetation Results

Mean Floristic Quality Assessment scores were calculated for the Level 3 assessment sites. Scores range from 0 for noxious weeds to 10 for plant taxa that exhibit a very narrow range of ecological tolerance and are found in areas with very narrow habitat requirements. Results are shown in Table 2.

Table 2: Mean FQI scores for eight sites in the Birch Creek Watershed

Wetland Ecological System No. Mean Min Max

Great Plains Prairie Pothole 3 40.7 36.8 46.6

Great Plains Closed Depression 3 33.9 27.5 43.3

Great Plains Saline Spring/Depression 1 47.5 - 47.5

Rocky Mountain Subalpine-Montane Riparian Shrubland 1 39.4 - 39.4

Great Plains prairie potholes contain, on average 22 species (r17-27), while closed depressions contain on average 20 species (r 18-22). One closed depression, mapped as an NWI wetland during the 1970’s, with a temporary flooding regime, has been invaded by upland species and contains only FAC wetland species at less than 20% cover. Some potholes and closed depressions that were assessed are more species rich than those found further east on the

9

Reservation and in the greater Prairie Pothole Region (PPR). Potholes located close to the mountains, but occurring in grasslands, frequently contain culturally significant species such as sweetgrass (Hierochloe hirta) and wapato (Sagittaria species).

Aspen forested depressions, although common in the area, were not sampled intensively. However, these often contain emergent communities of pondweed (Potamogeton species), woolly sedge (Carex pellita), Northwest Territory sedge (Carex utriculata), water sedge (Carex aquatilis), boreal mannagrass (Glyceria borealis) and some contain wetland Species of Concern. Bordering forests are composed of aspen and cottonwood with redosier dogwood (Cornus sericea) as a co-dominant or occasionally quaking aspen/bluejoint (Populus tremuloides/Calamagrostis canadensis). The quaking aspen/black cottonwood/western sweetroot (Populus tremuloides/Populus balsamifera L. ssp. trichocarpa/Osmorhiza occidentalis) community type borders wetland margins in area forested potholes. These potholes are widely known as important grizzly and black bear habitat, especially during spring months (Cooper and Jones 2003). Submergent communities are often dominated by sago pondweed/shortspike watermilfoil (Stuckenia pectinatus/Myriophyllum sibiricum), important waterfowl forage.

One riparian wetland sampled was especially species rich (55) taxa, occurring at 1496 m on soils overlying limestone bedrock. Dominant communities in this riparian area included black cottonwood/redosier dogwood (Populus balsamifera/Cornus sericea) and Booth’s willow/Mesic Forbs (Salix boothii/Mesic Forbs).

The most commonly encountered emergent plant community in all sites was common spikerush (Eleocharis palustris). Open water emergent communities included arumleaf arrowhead (Sagittaria cuneata), common bladderwort (Utricularia macrorhiza), hardstem bulrush (Schoenoplectus acutus), water sedge (Carex aquatilis), hemlock water parsnip (Sium suave), Alaska rush (Juncus arcticus) and needle spikerush (Eleocharis acicularis). Common submergents included shortspike watermilfoil (Myriophyllum sibiricum), common mare’s tail (Hippuris vulgaris), pondweeds (Potamogeton species) and Chara algae. All of these species are preferred waterfowl food sources, emphasizing the importance of pothole wetlands for migratory and resident waterfowl and shorebirds in this Reservation watershed. A total of 17 herbaceous emergent, three woody shrub, one forested and two submergent plant communities were found in the eight Level 3 monitoring sites.

Application of Results

Many area wetlands can be conserved or restored due to exceptional water quality and ecological condition. Many occur in proximity to the cultural areas of the Badger-Two Medicine and Heart Butte community on tribal lands. Complexes of forested and Great Plains prairie potholes occur west and southeast of Heart Butte. Recommended conservation easement sites for wetlands and associated upland buffers, occurring on Tribal, allotted and fee lands, are described in the supplemental Wetlands Conservation report.

The Great Plains potholes, closed depressions and aspen forest potholes in the western area of the watershed are biologically significant; they contain high species richness and diverse

10

emergent communities which are frequently dominated by preferred waterfowl forage species. These pothole complexes are recommended for conservation and protection. Moreover, many potholes contain high frequency or diversity of cultural wetland species. Some forested potholes contain the Species of Concern, Crawe’s sedge (Carex craweii).

Vegetation monitoring results and field surveys from Birch Creek indicate an immediate need for weed management. Introduction of bio-control insects for Centaurea stoebe is needed throughout area. Importantly, a population of Poison European water hemlock (Conium maculatum L.) was detected on adjacent lands near Swift Dam and the Lewis and Clark National Forest during the Birch Creek wetland field surveys. Conium maculatum is listed as a Priority 1 Noxious Weed species in the Rocky Mountain States of Colorado, Idaho and New Mexico and the prairie provinces of neighboring Alberta and Saskatchewan. It is listed as a noxious species in an additional 5 western states and is a Category Noxious Weed in several states of the central and eastern United States. All parts of the plant are highly poisonous to humans, livestock and wildlife. Human deaths have occurred due to ingestion of roots mistaken as native edible or medicinal species.

Currently, this species is not listed as a noxious species in Montana and Wyoming however, the species has become invasive in disturbed wetlands, riparian areas and mesic, open forests and meadows, as well as drainage ditches in north-central Montana and eastern Montana. It is very problematic in riparian wetlands and wet meadows on the Rocky Boy Reservation. The species can become invasive in wetlands, riparian areas and mesic aspen forested communities of the Blackfeet Reservation. Every effort to exclude and contain nearby populations is needed to protect water and wetland resources as well as canal function.

The Birch Creek watershed is currently free of invasive woody species such as Russian olive (Elaeagnus angustifolia). Vulnerable areas to invasion include the eastern sections of Birch Creek and the Alkali Lake vicinity. Saltcedar (Tamarix ramosissima) has recently been found in the Missouri Breaks region of north-central Montana. Exclusion of these invasive woody species is of paramount importance to preserve Reservation riparian functionality, water storage and biodiversity. Colonization of these species is of greater concern in the eastern third of the Two-Medicine/Birch Creek watersheds. Finally, monitoring results can be used to develop and implement the Birch Creek Watershed Management Plan and area wetland preservation, conservation and restoration projects.

Recommendations for Future Wetland Monitoring in Birch Creek Watershed

Riparian areas in the Blacktail and Whitetail areas can be inventoried for species richness, and characterized by the overstory mixtures of black cottonwood (Populus balsamifera), narrowleaf cottonwood (Populus angustifolia) and lanceleaf cottonwood (Populus acuminata), where the range of these species overlap. These communities can serve as reference sites. Natural regeneration and stand structure can be sampled and applied to cottonwood restoration projects elsewhere in southwestern Alberta and northern Montana. Additional sampling and assessments can occur in the aspen forested pothole region in the southwestern portion of the watershed. Additional data from forested potholes may reveal additional locations of Montana

11

Plant Species of Concern and contribute to a larger dataset for conservation and restoration of forested potholes in the southwestern corner of the watershed. Calcium rich springs and wetlands in the Major Steele Backbone area of Swift Dam may contain additional occurrences of rare species.

Several Great Plains prairie potholes and closed depressions located in the western third of the watershed near Swift Dam occur on private ranches and appear to be in good to excellent condition. These potholes are important for migratory waterfowl and contribute to the network of available pothole habitat in the Swift Dam area. Conservation easements may be considered by landowners. Similarly, a series of closed depressions and potholes, many of which are especially species and wetland plant community rich occur south of Heart Butte, on Tribal and private ranch land. These wetlands are also candidates for wetland conservation easement programs. Beaver influenced riparian complexes, near Swift Dam and Heart Butte, as well as mountain/foothill areas just north of the watershed (Two Medicine) can be targeted for water and wetland conservation efforts to conserve high water quality in headwater areas and to promote water storage. These wetlands are especially important for local climate change adaptation planning and are crucial for the drier watersheds of the Reservation along the Rocky Mountain Front, south of Glacier National Park.

It is also recommended that wetlands and riparian areas near Alkali Lake and in river floodplains of the Birch Creek and Two Medicine watersheds be surveyed for invasive woody species; to ensure that new populations are eradicated before these species have the potential to spread elsewhere on the Reservation.

12

References

Blackfeet Tribe Surface Water Quality Standards and Anti-Degradation Policy. 2013. Blackfeet Environmental Office. Prepared for the US Environmental Protection Agency. 61 p.Cannon, MR. US Geological Service. 1996. Geology and Groundwater Map of the Blackfeet Reservation, northwestern Montana.

Cooper SV and WM Jones. 2003. Site descriptions of high quality wetlands derived from existing literature sources. Montana Natural Heritage Program. Helena Montana. 68 p.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 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.

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. 2015. Coefficients of Conservatism for the Flora of Montana. Part 1. Montana Natural Heritage Program. Helena, MT. Prepared for the MT Dept. of Environmental Quality. 60 p.

Montana Natural Heritage Program. 2014. 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/.)

13