Ecological dynamics

Ecological Dynamics of the Site
This ecological site is found in the montane zone, with an elevation range of 1,400-2,000m, on backslope positions with moderate slopes of 4-15 percent and southwesterly aspects on marginal ground moraines and complex landslides on lateral moraines. Infrequently, this site is found on alluvial fans, hogbacks, knobs, ledges and knolls. These are large patch sized meadows. Within the montane lifezone, it is associated with the 43B Montane Deciduous Clayey Outwash Terrace, found on moister site locations. At harsher site locations of this ecological site, it is associated with the
43B Subalpine Windswept Shallow Meadow.

State 1.0
Historic Reference state with no weedy species present.
Rough fescue (Festuca campestris)/shrubby cinquefoil (Dasiphora fruticosa)/Idaho fescue (Festuca idahoensis)/yarrow (Achillea millefolia)-northern bedstraw (Galium boreale)-Ross’s sedge (Carex rossii).

This 43B Montane Very Deep Meadow ecological site is dominated by rough fescue (Festuca campetris) with associated montane grasses and forbs. Idaho fescue (Festuca idahoensis) and shrubby cinquefoil are common, but occur in much lower canopy cover. Other associated grasses occurring infrequently but in moderate cover include: rough bentgrass (Agrostis scabra), Richardson’s needlegrass (Achnatherum richardsonii), alpine timothy (Phleum alpinum), alpine bluegrass (Poa alpina) and blue wildrye (Elymus glaucus). Associated montane forbs include: yarrow (Achillea millefolia), bluebell bellflower (campanula rotundifolia), nineleaf biscuitroot (Lomatium triternatum), lupine species and northern bedstraw (Galium boreale). Montane shrub species that can occur although in very low cover including: white spirea (Spirea betulifolia), thimbleberry (Rubus parviflorus), serviceberry (Amalanchier alnifolia), creeping juniper (Juniperus horizontalis), kinnikinnick (Arctostaphylos uva-ursi), Wood’s rose (Rosa woodsii) and sulphur-flower buckwheat (Eriogonum umbellatum). This community is predominantly herbaceous with an average total canopy cover of 96 percent and shrub/sub-shrub canopy cover 9 percent relative canopy cover. This relates primarily to the National Park Service Grasslands Report (Asebrook, 2010) classifications of Festuca campestris-Festuca idahoensis/Geranium viscosissimum and Dasiphora fruticosa/Festuca campestris associations predominantly. Hansen et. al. (1995) found that shrubby cinquefoil, yarrow and northern bedstraw were fair to poor forage for cattle, horses and sheep, whereas Idaho fescue was good forage for all. Shrubby cinquefoil had medium energy value and low protein value for the fall and winter. Idaho fescue had high fall winter energy value and medium protein value. Yarrow and northern bedstraw were low for both energy and protein values in fall and winter. Shrubby cinquefoil was considered poor cover for elk, mule deer, whitetail deer, upland birds, waterfowl, small non-game birds and small mammals. It was fair food value for elk, deer and antelope, but poor for bird species. Yarrow and northern bedstraw were poor food value for elk, deer species and antelope and bird species.

Rough fescue and elk sedge are considered very resistant to human trampling in a study by Cole (1987) assessing human trampling effects on vegetation to recommend campground placement in the backcountry. This is due to its tough core of the tuft (Cole, 1987). The majority of the loss of cover, reduction by 50 percent, occurred in the first 400 passes. Thereafter, cover loss was stabilized from 400-800 passes. The community of rough fescue-timber oatgrass is considered very resistant to both light and heavy trampling. Human trampling is different from wildlife or livestock trampling in the weight of the animal, size, structure and action of a hoof versus a foot.

Rough fescue is a native, cool season, perennial bunchgrass that produces thick mats of persistent sheath and stem bases and culms that grow to 107cm (3.5 feet) and leaf tufts that grow to 41cm (16 inches) in height (Cronquist, 1977). It has extensive fibrous roots to a depth of 122 cm (4 feet), 73 percent of which are concentrated in the top 15 cm (6 inches) of soil (Coupland, 1953). It regenerates from seed, tillers and sometimes rhizomes (Pavlick, 1984). It is well adapted to a short growing season by initiating growth following snowmelt and completes growth before the onset of summer drought. It is very productive and highly palatable to livestock and wildlife. It is used by bighorn sheep, mule deer, elk and bison. It is resistant to moderate grazing but heavy grazing can result in severely decreased root depth and biomass (Aiken, 1990). Grazing can cause a general decline in rough fescue coverage, and is one of the first species to decline with a concomitant increase of common increasers species with grazing such as Idaho fescue, needlegrass species, prairie Junegrass, and Parry’s oatgrass.

It is well-adapted to periodic burning and resistant to light fire by their dense, tufted habit. It sprouts from surviving residual plants and colonizes from off-site wind-dispersed seed. Fire may top-kill plants, but cover and production usually is attained in 2-3 years post-fire. Severe damage can occur by hot, mid-summer wildfires (Wright, 1982).

Due to a lack of fire, a shrub-encroached phase does exist that has a high cover of shrub species, including serviceberry (Amelanchier alnifolia), kinnikinnick (Arctostaphylos uva-ursi), shrubby cinquefoil (Dasiphora fruticosa), sulphur-flower buckwheat (Eriogonum umbellatum), Wood’s rose (Rosa woodsii), snowberry (Symphoricarpos albus), and thimbleberry (Rubus parviflorus). Serviceberry and shrubby cinquefoil dominate the shrub overstory. Infrequent shrub species that can occur include russet buffaloberry (Shepherdia canadensis), dwarf bilberry (Vaccinium cespitosum), red baneberry (Actaea rubra), common juniper (Juniperus communis), and creeping barberry (Mahonia repens). The understory is dominated by rough fescue (Festuca campestris) and low cover of Idaho fescue (Festuca idahoensis). This community consists predominantly of herbaceous species ranging from 60-93 percent and averaging 77 percent, and shrub species that range in total average cover from 21-70 percent (39 percent average). There is a very low cover of trees at these sites (2 percent average canopy cover) with a variety of species including lodgepole pine (Pinus contorta), black cottonwood (Populus balsamifera), and aspen (Populus tremuloides).

Invasion Theory
Invasion of weedy species into native vegetation communities requires an understanding of the processes and mechanisms by which an invasion occurs. Resistance and resilience of the native community are essential elements in predicting the success of the invasion. There are two counter point theories on invasive species. The driver theory considers the invasive species to be driving species decline while the passenger model sees the invading species as filling in empty niches left by habitat alteration (Didham, 2005). The passenger model suggests that disturbance is the cause and if stopped, invasion can be reversed. Potential mechanisms of invasion include theories such as novel weapons, enemy release, competitive superiority, and manipulation of environment. Novel weapons include biological weapons or associations with micro-organisms that allow the invader species to either access new resources or steal them from indigenous plants (Tannas, 2011). Specifically, arbuscular mycorrhizal fungi may provide a substantial competitive advantage to spotted knapweed by carbon parasitism (Carey, 2004). In these cases, the invader uses these weapons to drive the invasion process. Enemy release describes the concept that once invader species are released from their native predator species or chemical warfare within their original community, they are more aggressive in their new community (Blumenthal 2006, Callaway and Aschelhoug 2000). The invader species may have characteristics that allow it to be more competitive than resident plant species such as grazing resistance, adaption to a harsh environment or another competitive ability (Tannas, 2011). Invading species can manipulate the environment to their advantage through resource competition. Mechanisms include modifying light interception, water uptake efficiency or change in soil water holding capacity, nutrient uptake and cycling (D’Antonio and Vitousek, 1992). The final outcome of invasion is establishment of the invading species which occurs as either dominance, coexistence, or exclusion from the indigenous plant community (Seabloom, 2003). D’Antonio and Vitousek (1992) stated grass invasions are particularly important because they are actively moved by humans and exotic grasses compete effectively with native species in many ecosystems. In addition, dominant grasses may change nutrient cycling, modify regional microclimates and alter fire dynamics.
Invasive Species Descriptions
Specifically, scientific literature on invasions by Kentucky bluegrass, smooth brome, spotted knapweed, leafy spurge and Canada thistle into rough fescue grasslands in Canada and Montana will be reviewed. Kentucky bluegrass invasion into rough fescue grasslands can take multiple pathways. Heavy grazing of rough fescue which reduces litter amount combined with timing of defoliation, winter versus growing season and abiotic factors like seasonal variation in soil moisture content can make native grasslands less resistant to invasion (Douwes, 2012, Tannas, 2012). Resilience of the native grassland is dependent on vigor and density of rough fescue and restoration establishment is more successful with cuttings and plugs than seeding (Tannas, 2011). Although, seeding rough fescue as a monoculture is effective (Sherritt, 2012). A study of grazing effects on a rough fescue at Stavely grassland, a Canadian research station, found that heavy grazing pressure by cattle resulted changes in plant species composition to an increase in shallow rooted species, less productive overall, but more resistant to grazing (Dormaar, 1990). In a study of seasonal biomass changes, Willms (1996) found that with grazing intensity the vegetation community composition shifted from one dominated by rough fescue to one dominated by parry oatgrass-Kentucky bluegrass in moderately grazed pastures to Kentucky bluegrass-sedge species in heavily grazed pastures. The rough fescue dominated community had the greatest forage value compared to communities resulting from moderate, heavy and severe grazing (Willms, 1996). More than 20 years of drastically reduced stocking rates were required to enable recovery (Willms, 1985). Soils associated with heavy grazing were transformed to a soil more characteristic of a drier microclimate (Johnston, 1962 and 1971), by reducing the thickness of Ah horizon, reducing percent organic matter and soil moisture and increasing soil temperature with grazing intensity. Heavy grazing also reduced the fertility and soil water holding capacity (Dormaar, 1998). Soil organic matter, and nutrient cycling differed between grazed and ungrazed rough fescue grasslands (Willms, 1988). At a watershed scale, heavy grazing lead to larger summer storm and spring snow melt runoff compared to watersheds with less grazing (Chanasyk, 2002). The quantity and quality of surface runoff from these watersheds showed that grazing posed little risk of nutrient contamination of adjacent streams (Mapfumo, 2002). There was less snow accumulation in heavily and moderately grazed watersheds (Willms, 2006). A study on the effects of grazing on germinable seeds found that soil disturbance in fescue grassland is more likely to lead to a seral community dominated by annual broad-leafed plants, than a rough fescue dominated grassland (Willms, 1995). Skim grazing (light, once-over-spring defoliation) by cattle was not conducive to rough fescue conservation (Moisey, 2005). Rough fescue tolerated light winter-early spring elk grazing but not heavy grazing (Thrift, 2013). A rough fescue grassland in Rumsey Block, Alberta Canada tolerated moderate grazing which resulted in a community co-dominated with shortbristle needle and thread while heavy grazing and/or moderate to major oil and gas disturbance crossed a threshold requiring complete eradication of species and reseeding (Desserud, 2014). Another study of effects of human caused disturbance in rough fescue grasslands in Manitoba Canada, found it depends on invasive species introduction history (Gifford, 2013). Kentucky bluegrass tolerates grazing and can increase in abundance after heavy grazing. Therefore, Kentucky bluegrass resided in historically grazed areas, while smooth brome occurred along roads. In a study of smooth brome on rough fescue grasslands in Saskatchewan Canada, found that it is likely the combination of traits of smooth brome (higher productivity, abundant production of lower quality litter, clonal growth, and greater nutrient uptake capability) that allows it to invade native prairie (Piper, 2015). Smooth brome had a consistent negative impact on community structure and function across 8 grasslands in Alberta Canada with the impact on native species richness higher in species rich areas, while impact on native biomass was larger in productive, warmer and more variable sites (Stotz, 2016).
The noxious weed spotted knapweed was found to strongly reduce the final biomass and reproduction of native Idaho fescue grasslands. An insect biocontrol agent had little effect on spotted knapweed, while a native fungal pathogen killed it in a common garden experiment in Missoula Montana (Ridenour, 2003). Perry (2005) found that invasion of grasslands by spotted knapweed are mediated by root exudation of catechin, a potent phytotoxin. Catechin resistance was positively correlated with mean seed mass for eight species identified as resistant: Mountain brome, curlycup gumweed, needle and thread grass, basin wildrye, cicer milkvetch, boreal sweetvetch, common blanketflower, and alfalfa. Perry (2005) further found that residual soil catechin may interfere with reestablishment of native grassland species even after spotted knapweed populations are controlled.
Leafy spurge has an extensive rhizomatous root system, potential allelopathic properties and all parts contain high starch latex which seals wounds and is a possible deterrent against insect attacks. Areas with leafy spurge invasion that have been treated with herbicide application and mechanical removal still had higher bare ground area, significantly lower soil arthropod densities and lower plant species richness and cover (Pritekel, 2006). Jordan (2008) found that invasive plants, specifically leafy spurge, smooth brome and crested wheatgrass, are capable of modifying soil microbiota to facilitate further invasion by conspecifics and other invasive species. These soil alterations have the potential to impede restoration of native communities after removal of an invasive species. Successional management may require repeated treatments to achieve a desired outcome. Pokorny (2009) found that while broadleaf herbicide applications decreased hoary cress, Canada thistle and undesired forbs within a leafy spurge invaded site, the results were temporary, and seeding was necessary for native species establishment.

Community Phase 1.1: rough fescue (shrubby cinquefoil/Idaho fescue/yarrow-northern bedstraw-bluebell bellflower
This phase is dominated by rough fescue with associated montane grasses, primarily Idaho fescue, forb species, and shrubs in very low cover, primarily shrubby cinquefoil.

Community Phase 1.2: Saskatoon serviceberry (kinnikinnick-sulphur flower buckwheat)/rough fescue-Idaho fescue/yarrow
This phase is dominated by serviceberry and shrubby cinquefoil in the overstory and by rough fescue in the understory. The same suite of montane shrubs, grasses, and forbs found in Phase 2.1 are found in this phase.

Community Phase Pathway 1.1A
This pathway represents a significant time without fire, such that the historic fire return interval is lengthened, and shrub and conifer species invade.

Community Phase Pathway 1.2A
This pathway represents a resumption of historic fire return intervals, such that woody shrub and conifer encroachment is killed, and grasslands are sustained.

Community Phase 2.1: rough fescue (shrubby cinquefoil/Idaho fescue/yarrow-northern bedstraw-bluebell bellflower
This phase is dominated by rough fescue with associated montane grasses, primarily Idaho fescue, forb species, and shrubs in very low cover, primarily shrubby cinquefoil. This ecological site has high foliar cover (average 81%), low to moderate basal cover (10-15%) and high litter cover (average 85%) under the litter is soil.

Community Phase 2.2
This community has sustained either severe drought or heavy grazing, which has reduced the cover and vigor of rough fescue and increased the cover of Idaho fescue, needlegrass species, and prairie Junegrass. If even these native bunchgrasses decreased significantly, then a transition would occur out of this State 2.

Community Phase 2.3: Saskatoon serviceberry (kinnikinnick-sulphur flower buckwheat)/rough fescue-Idaho fescue/yarrow
This phase is dominated by serviceberry and shrubby cinquefoil in the overstory and by rough fescue in the understory. The same suite of montane shrubs, grasses, and forbs found in Phase 2.1 are found in this phase.

Community Phase Pathway 2.1A
This pathway represents heavy grazing or improper grazing management for sustained periods of time.

Community Phase Pathway 2.2A
This pathway represents a ceasing of heavy grazing or improper grazing management for sustained periods of time.

Community Phase Pathway 2.1B
This pathway represents a significant time without fire, such that the historic fire return interval is lengthened, and shrub and conifer species invade.

Community Phase Pathway 2.3A
This pathway represents a resumption of historic fire return intervals, such that woody shrub and conifer encroachment is killed, and grasslands are sustained.

Transition T1A:
This represents the pathway from the historic Reference state in which there were no weedy species present in the vegetation community (State 1.0), to the introduction and establishment of weedy species, even at very low canopy cover values, within the vegetation community of State 2.0.

Transition T2A:
This pathway represents weed infestation from human, animal, or transportation corridors that allow non-native species to invade and establish within the grassland to the degree that native grass species decline.

Restoration R3A:
This pathway represents proper grazing management that allows the cover and vigor of native bunchgrass, particularly rough fescue, to be restored. Other means such as chemical, mechanical, or biological may be needed to restore native bunchgrass species to dominance.

Summarization of canopy cover data including constancy and canopy cover values (average, minimum and maximum) per species present at community phase 2.1 of this ecological site, 7 sites (includes NPS original data and NRCS revisit vegetation data). Rough fescue (21% average canopy cover) and Idaho fescue (9% average canopy cover) are indicator species for this ecological site with high frequency of occurrence and canopy cover. Other species with high frequency of occurrence include yarrow, shrubby cinquefoil, northern bedstraw and sulphur-flower buckwheat.

Summarization table for foliar cover at community phase 2.1 of this ecological site, 3 NRCS sites. Rough fescue dominates the foliar cover at these sites. Secondarily, Idaho fescue, blue wildrye, shrubby cinquefoil, northern bedstraw and yarrow contribute to foliar cover. Foliar cover is high at these sites (81%) and the ground cover is predominantly litter with soil underneath (85%) and very low bare ground (1%). There is some gravel (10%) and moss (3%). Structure at this vegetation community is composed of three layers. Species in the taller layer (25-51 cm or 10-20 inches) include sticky purple geranium, rough fescue, serviceberry, shrubby cinquefoil, pinegrass, idaho fescue and nineleaf biscuitroot. The middle layer is 15-23 cm or 6-9 inches tall and includes alpine leafybract aster, sulphur-flower buckwheat, northern bedstraw, dwarf bilberry. The lowest layer is 15 cm 6 inches or less and includes yellow penstemon, poa, sedum and vicia species.

Summarization of production in pounds per acre at community phase 2.1 of this ecological site, 2 NRCS sites. Rough fescue dominates the average annual production, secondarily these species contribute: sulphur-flower buckwheat, shrubby cinquefoil, northern bedstraw, Idaho fescue and alpine leafybract aster.
SPECIES TOTAL PRODUCTION AVERAGE= 1651#/ACRE (range= 1514#/acre-1789#/acre) 2SITES

Summarization of canopy cover point data for community phase 2.3 of this ecological site including constancy and canopy cover values per species present at this site, 6 NRCS sites. Species with high constancy occur often, those with low constancy are rare. The average canopy cover is the average of the values for which it occurred. Therefore, species that are rare (only occurred once) show the canopy cover value for the one time it was found. Minimum and maximum canopy cover show the range of cover that the species was found. This is the shrub dominated community phase of this ecological site with serviceberry, sulphur-flower buckwheat and shrubby cinquefoil occurring frequently with moderate to high canopy cover. Infrequently, kinnickinnik and common snowberry occurs with moderate frequency of occurrence and canopy cover.

Foliar cover point data for community phase 2.3 of this ecological site, three NRCS sites. Species with high ranges of foliar cover include shrubby cinquefoil, white spirea, thimbleberry, yellow penstemon, pinegrass, and western meadowrue.

TOTAL FOLIAR COVER 69-99% 3 SITES
SPECIES FOLIAR COVER RANGE IN PERCENT

Summarization of production point data for community phase 2.3 of this ecological site in pounds per acre, at one NRCS site. Rough fescue and dwarf bilberry dominate the average annual production. Species with moderate production include pinegrass, shrubby cinquefoil, pale agoseris, strawberry and lupine species.
SPECIES TOTAL PRODUCTION 1896 1 SITES

State 3.0:
This state represents the community with significant increase in weedy species and concomitant decrease in native grass species.

Community Phase 3.1:
This community phase is dominated by the weedy species phleum pratense, poa pratensis, taraxacum offinale and Centaurea stoebe with less amounts of the native vegetation community of this ecological site found in 2.1. Shrubs generally are very low and cover no more than 10 percent of the site. Diverse montane meadow forbs are associated with this site. Tree encroachment is very low, mainly consisting of lodgepole pine at the edges of the prairie.

Community Phase 3.2:
This community has sustained shrub or tree encroachment due to a lack of fire, and is dominated by the weedy species phleum pratense, poa pratensis, taraxacum offinale and Centaurea stoebe with less amounts of the native vegetation community of this ecological site found in 2.3.

Community Phase Pathway 3.1A
This pathway represents a significant time without fire, such that the historical fire return interval is lengthened, and shrub species invade. Weedy species are still present within the community.

Community Phase Pathway 3.2A
This pathway represents a resumption of historic fire return intervals, such that woody shrub and conifer encroachment is killed, and grasslands are sustained.