Ecological dynamics

The dominant visual aspect of this site is broadleaf cattail and/or hardstem bulrush. Hardstem bulrush is more dominant where water is 6 to 8 inches deep or deeper throughout the growing season. Broadleaf cattail is often more dominant where the water is at the soil surface through most of the growing season and may dry out at the surface later in the summer. When the two species occur together, broadleaf cattail is in shallower water than the hardstem bulrush. This is common on margins of ponds, lakes, and reservoirs.

The site often occurs within a complex of wetland sites when adjacent to streams or rivers. In these situations, the soil surface of the area where the site is found is typically slightly undulating causing small depressions and high spots with variable soil moisture regimes. The plant communities found on these areas are sites within the complex. Characteristics of these sites are as follows:

1. Marsh site. Deeper depressions with the water table at or near the surface or slightly above the surface for the entire growing season. This site is dominated by broadleaf cattail, hardstem bulrush, and common threesquare.

2. Wet Meadow site. Shallow to depression areas with the water table at or near the surface for the entire growing season. This site is dominated by Carex spp. and Junus spp.
3. Meadow site. Slightly higher areas that are drier during the growing season. The water table is down to a depth of 20 to 40 inches by the end of the growing season. This site is dominated by tufted hairgrass and Nebraska sedge.

4. Dry Meadow site. Even higher areas that are even drier during the growing season and the water table is > 40 inches deep by the end of the growing season. The plant community is dominated by Nevada bluegrass and alpine timothy.

Either hardstem bulrush or broadleaf cattail can form impenetrable monotypic stands. Composition by weight is 95 percent grass or grass-like and 5 percent forbs.

During the last few thousand years, this site has evolved in a semi-arid and montane climate characterized by dry summers and cold, moist or wet winters. The site has evolved on deep alluvial soils that are saturated at the soil surface or standing water throughout most of the growing season. Herbivory has historically occurred on this site at very low levels of utilization. Herbivory by some small mammals such as muskrats does occur.

Fire has had little influence on the development of the site. Rare wildfires can occur following consecutive drought years, particularly broadleaf cattail stands that go dry late in the summer.

The conditions for the plant community of this site are variable due to differences in the duration and depth of standing water. Dominant species are mostly rhizomatous and can form monotypic stands.

An infinite number of combinations of factors that influence the ecology of potential plant communities exist. For practical purposes, four plant communities where the depth to the water table drives the vegetative composition have been described. They are:

• Dry meadow Water table at >40” at end of growing season
• Meadow Water table at 20-40” at end of growing season
• Wet meadow Water table at 10-20” at end of growing season
• Marsh Water at surface to <10” at end of growing season


Most wetland species have a wide range of tolerance for variations in soil moisture. Most species occur in more than one site, although most are dominant on just one site.

The following table shows the amplitude of wetland species that occur on the four sites.


• Ecological Amplitude of Meadow/Marsh Plants.

Grass and Grass-like Species
Scientific name Dry Meadow Meadow Wet Meadow Marsh
Leymus cinereus

Danthonia californica

Carex filifolia

Pascopyron smithii

Poa nevadensis

Juncus dudleyi

Muhlenbergia richardsonis

Hordeum brachyantherum

Phleum alpinum

Scientific name Dry Meadow Meadow Wet Meadow Marsh
Juncus balticus

Juncus torreyi

Alopecurus aequalis

Carex athrostachya

Calamagrostis canadensis

Deschampsia caespitosa

Carex nebrascensis

Glyceria striata


Carex lasiocarpa

Carex utriculata

Carex aquatilis

Eleocharis palustris

Carex rostrata

Carex hoodii

Carex exsiccata

Scirpus microcarpus

Juncus effusus

Beckmannia syzigachne

Typha latifolia

Schoenoplectus acutus

Schoenoplectus pungens

Sparganium erectum

Schoenoplectus tabernaemontani


Forb Species
Scientific name Dry Meadow Meadow Wet Meadow Marsh
Arnica fulgens

Pyrrocoma lanceolata

Arenaria congesta

Artemisia ludoviciana

Achillea millefolium

Wyethia amplexicaulis

Pyrrocoma uniflora

Ranunculus spp.

Trifolium spp.

Potentilla gracilis

Senecio integerrimus

Aster spp.

Cirsium scariosum

Symphyotrichum ascendens

Iris missouriensis

Senecio serra

Helianthus nuttallii

Camassia quamash

Epilobium ciliatum

Montia chamissoi

Plantago major

Alisma triviale

Cicuta douglassii

Argentina anserina

Scientific name Dry Meadow Meadow Wet Meadow Marsh
Veronica anagallis-aquatica

Symphyotrichum frondosum

Polygonum bistortoides

Triglochin maritimum

Polygonum amphibium

Symphyotrichum foliaceum

Potamogeton natans

Lemna minor



The Historic Climax Plant Community, the Reference State (State 1), moves through many phases depending on the natural and man-made forces that impact the community over time. State 1, described later, indicates some of these phases. The Reference Plant Community Phase is Phase A. This plant community is dominated by broadleaf cattail and/or hardstem bulrush. There are a few forbs that may occur in minor amounts including water knotweed, leafybract aster, floating pondweed, and common duckweed. There may also be other grass-like species occurring in minor amounts. The plant species composition of Phase A is listed later under “Reference Plant Community Phase Plant Species Composition”. The Reference Plant Community is intentionally written broadly, but these species should occur in the plant community in variable amounts.

The total annual production is 4500 pounds per acre (5040 kilograms per hectare) in a normal year. Production in a favorable year is 5500 pounds per acre (6160 kilograms per hectare). Production in an unfavorable year is 3500 pounds per acre (3920 kilograms per hectare). Most of this variation occurs from temperature differences, not moisture. Structurally, rhizomatous grass and grass-like species are very dominant, followed by perennial forbs.

FUNCTION:

This site is suitable for waterfowl, some shore birds, and small mammals. Moose graze the site occasionally. The site is not suitable for livestock grazing or big game, although some deer may use the edges for cover. Standing water limits grazing opportunities. In some drought years, some grazing can occur with livestock although wet soils should be avoided.

This site can be used for waterfowl hunting and may be adjacent to open water that offers fishing opportunities.

The site is very resistant to degradation due to standing water, low value and unpalatable forage, and limited grazing opportunities. Site degradation is usually the result of permanently lowering of standing water. This can occur with down cutting of adjacent stream channels. This can result from off-site conditions adjacent to the site or in the upper watershed. Once adjacent streams are down-cut, concentrated flows can lower the water table and standing water on the site.


Impacts on the Plant Community:

Influence of fire:

This site usually does not burn from wildfire. A rare fire may occur following prolonged drought. If a fire occurs, it usually does not adversely affect the plant community due to rhizomatous species. Most plants sprout back.

Influence of improper grazing management:

Due to standing water and low value forage, grazing during the growing season is rare. Grazing may occur during the dormant period. If dry soil conditions occur into the spring and livestock remove the tops of either broadleaf cattail or hardstem bulrush, the plants can die if water then covers them. Care must be exercised in grazing adjacent sites to avoid downcutting of stream channels that can influence standing water on this site. The potential of the site can be lost.

Weather influences:

Annual precipitation has little direct influence on this site. Prolonged drought can affect amounts and duration of standing water and can change the composition of this site.

Carex and Juncus species can increase and broadleaf cattails and hardstem bulrush can decrease. Lower production can occur with below normal spring temperatures that affect both air and water. An early, hard freeze can occasionally kill some plants.

Influence of Insects and disease:

Periodic disease and insect outbreaks can affect vegetation health. An outbreak of a particular insect is usually influenced by weather but no specific data for this site is available.

Influence of noxious and invasive plants:

Purple loosestrife can become invasive, but most plants on this site are very competitive against most potentially invasive species due to monotypic stands of plants with strong rhizomes.

Influence of wildlife:

This site is important for many species of waterfowl. Some small mammals and shore birds also use the site. Moose graze the site periodically. Big game animals use the edges for cover. Total numbers are seldom high enough to adversely affect the plant community.

Watershed:

The largest threat to degradation of this site is the lowering of permanent standing water during the growing season. Off-site conditions can affect the gradient of adjacent stream channels that can affect the water table. If down-cutting of adjacent streams occur, this can reduce the depth and duration of the standing water. High run-off events from the adjacent uplands can severely damage or change the normal stream channel on the site. As the standing water is permanently reduced, either in depth or duration, productive potential is lost. Eventually the standing water is no longer the driving factor for the plant community. The site may regress to a meadow or even a low seral upland site.


Plant Community and Sequence:

Transition pathways between common vegetation states and phases:

State 1 to State 2. Develops through permanently reducing the standing water during the growing season to the point that dry soil is at the surface during the growing season. This can occur with down-cutting of adjacent stream channel. This site has crossed the threshold. This state cannot be returned to state 1 without returning the standing water regime.

Practice Limitations:

There are severe limitations to facilitating or accelerated practices due to standing water.