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Onion Ridge Proposed Natural Area Preserve Recommendation

Submitted by Joe Rocchio, Washington Dept. of Natural Resources, Natural Heritage Program

Submitted to Natural Heritage Advisory Council

March 27, 2020 (Revised version submitted on June 4, 2020)

Background

The Washington Natural Heritage Program (NHP) first submitted a recommendation for establishing the

Onion Ridge Natural Area Preserve in 1991. This document updates the 1991 recommendation with

recent field observations and a revised proposed NAP boundary.

Onion Ridge is located sixteen miles north of Colville in Stevens County (Figure 1). The site occurs within

the Canadian Rockies ecoregion but is very close to the boundary with the Okanogan ecoregion (Figure

2). The boundary proposed in 1991 encompasses 1,346 acres and is shown in Figure 3. The 1991

recommendation was in response to local, citizen interest and concern for the area related to a timber

harvest that was proposed within the site. The Washington Environmental Council submitted a letter to

DNR in December of 1990 requesting the area be considered a “Natural Heritage Conservation Area”. The

Department of Wildlife, as well as a local interest group, also requested that DNR consider the area be

protected as a natural area due to supporting “unique” wetland characteristics and unharvested forests.

In response to these requests, DNR’s Northeast Region requested that the NHP conduct a “field

inspection, by your field experts to confirm whether or not the area would qualify [as a natural area] under

the Natural Heritage Program”. The result of NHP’s inventory concluded that the Onion Ridge Potential

Natural Area Preserve (pNAP) supported numerous ecosystem types and a rare plant species identified as

priorities in the Natural Heritage Plan. As such, NHP developed a natural area recommendation for the

site which the Natural Heritage Advisory Council approved in 1991. However, the site was never acquired

by DNR Natural Areas Program, presumably due to lack of political and/or region support. In the past

year, DNR’s Northeast Region reached out to NHP to indicate they were supportive of a natural area in

the Onion Ridge area. However, the Region noted they wanted to retain a portion of the 1991 NAP

boundary due to its operability for timber harvest operations.

In response to the Region’s interest, NHP staff revisited the site during August of 2019 to determine

current ecological conditions and assess the conservation impact of modifying the 1991 boundary. NHP

determined that ecological conditions of the site remained in excellent to good condition and that all the

elements remained present at the site. Although a reduced boundary would exclude significant areas of

the common forest communities, Natural Heritage Program and Natural Areas Program staff concluded

that the revised boundary presented in this document would still protect the primary NHP Plan features,

including those with the highest Priority status. As such, NHP is of the opinion that the 2020 pNAP

boundary would still provide significant and needed conservation to the priority features.

Size

The acreage of the proposed 2020 Onion Ridge pNAP boundary is 963 acres. The 1991 proposed boundary

encompasses 1,346 acres.

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Location

Onion Ridge is located sixteen miles north of Colville in Stevens County (Figure 1). The 2020 pNAP is

located in T38N R39E, Willamette Meridian Section 9 (E2), the majority of Sections 16 and 21 (central and

SE portion), and Section 28 (NE4) (Figure 4).

Ownership

The Department of Natural Resources manages the majority of the site. The northern portion (Section 9)

is managed by the U.S. Department of the Interior, Bureau of Land Management (Figure 5).

Primary Elements

The Onion Ridge pNAP is designed to protect numerous forest communities, bald communities, and

wetland communities identified as priorities in the 2018 Natural Heritage Program plan (Washington

Department of Natural Resources, 2018; Table 1). This diverse site supports four Priority 2 plant

communities, a Priority 3 plant community, and a Priority 3 rare plant.

There are four different Priority 2 elements supported at the site. These include: (1) Mid-elevation

Freshwater Wetlands; (2) Mid-elevation Permanent Ponds; (3) Idaho fescue / Parsnip-flowered

Buckwheat Grassland; and (4) Western Redcedar / Wild Sarsaparilla Forest. (Table 1).

Numerous plant communities (as defined by the U.S. National Vegetation Classification) are associated

with the Mid-elevation Freshwater Wetland found at the site (Table 1). Mid-elevation Permanent Ponds

are found in many of the wetland basins in the site. Some of the ponds have aquatic vegetation around

their perimeter and all have wetland communities (i.e., the Mid-elevation Freshwater Wetland element)

around their edges. The Idaho fescue / Parsnip-flowered Buckwheat Grassland is found on ridgetops or

around rock outcrops. The Western Redcedar / Wild Sarsaparilla Forest occurs as small stands at the base

of slopes and near many of the ponds within the NAP.

Two Priority 3 elements are supported in the site: the Douglas-fir / Mallow-leaf Ninebark – Twinflower

Forest and a population of the bulb-bearing water hemlock plant. The example of the Douglas-fir /

Mallow-leaf Ninebark – Twinflower Forest at Onion Ridge is among the best known in the state. The bulb-

bearing water hemlock (Cicuta bulbifera) is a state-rare plant found in two of the wetland within the NAP.

The Douglas-fir / Mallow-leaf Ninebark Forest is protected in four established natural areas and four

potential natural areas (including Onion Ridge) in eastern Washington. The example of this forest type at

Onion Ridge is among the best known in the state. The NHP Plan indicates this element is adequately

protected within the Canadian Rockies ecoregion, however that designation is based on the assumption

that the Onion Ridge occurrence remains protected.

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Figure 1. Location of Onion Ridge Potential Natural Area Preserve

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Figure 2. Onion Ridge Potential Natural Area Preserve and Ecoregions

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Landscape Context and Geology

Onion Ridge stretches for two miles along a one half­ mile wide ridge above the northwest reaches of the

Onion Creek drainage and a small glacial valley. This granite ridge is two miles east of the Columbia River

and divides the Onion Creek (east) and the North Fork of Bruce Creek (west) drainages.

O'Toole Mountain, elevation 4,112 feet, and Grande Mountain, elevation 4,119 feet, form the north and

south ends of the site, respectively. A cluster of ponds and wetlands occupy the saddle between the two

summits. The ponds are about 1,500 feet below O'Toole Mountain, less than one-half mile to the north

and Grande Mountain, over a mile to the south. The wetland saddle is perched 800 feet above Phalon

Lake at the head of the North Fork of Bruce Creek, approximately one-quarter mile to the west. The saddle

is at the top of a rise 1,000 feet above Onion Creek, 5.5 miles to the east. The site faces westerly.

Onion Ridge is located in the Kooteny Arc -- a complex geologic region between the North American

continent and the old Okanogan subcontinent (Alt and Hyndman 1987). The site is situated on the

convergent margin of the North American continent (Stoffel and others 1991). Outcropping bedrock

within Onion Ridge is of Cretaceous granite origin (Stoffel and others 1991). Ordovician meta­ argillite,

which originated on the continental shelf of North America, forms the north side of O'Toole Mountain. It

continues north to the Columbia River and is the exposed rock along the lower elevations of the Bruce

Creek canyon wall (Stoffel and others 1991). A fault line parallels the length of the canyon. Most of the

Onion Creek basin is covered with late-Wisconsin continental glacial drift (Stoffel and others 1991).

Glaciers overrode the area creating the system of tarns (ponds) and depositing material in many sites.

Volcanic ash covers the residuum and glacial deposition in some parts of the site. Large glacial erratics are

found throughout the site.

Topography and Soils

The result of this geologic history is a complex topography. Slopes are steep along the west boundary,

near the mountain summits, and along some of the ponds. Steep ridges and troughs describe the

topography of the saddle around the ponds. A series of benches and slopes appear along the slope to

Grande Mountain. The soils are mapped as the Newbell Rock outcrop Complex, Newbell stony silt loam

and the Moscow silt loam. Soils near ridgetops and around rock outcrops are coarse and very well drained.

Hydrology

The pNAP encompasses a nearly complete watershed that surrounds a series of twelve ponds, the upper

slopes of a north south tending ridge, and the steep west side of a U­ shaped valley (Figure 6). A cluster

of ponds and wetlands dot a 200 acre area below O'Toole Mountain (mostly in the NE corner and central

to south-central portion of Section 16; Figure 1, 6). These include O'Toole Lake, a 5 acre pond, and eleven

other ponds, the smallest less than one-half acre. Beaver have expanded some ponds, created a chain of

ponds in other areas, and have had little hydrologic influence in others. Most of the ponds drain westward

into North Fork of Bruce Creek, although some have no outlet stream. Two ponds are on the divide and

flow east or west depending on how beavers modify drainage patterns. Only two ponds, including O'Toole

Lake, are permanent ponds while other dry or dramatically contract during dry summer months (Wolcott,

1964).

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Figure 3. Onion Ridge Potential Natural Area Preserve Approved Boundary (1991).

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Figure 4. Onion Ridge Potential Natural Area Preserve Proposed Boundary (2020).

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Figure 5. Land ownership within the Onion Ridge Potential Natural Area Preserve Proposed Boundary

(2020).

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Table 1. Natural Heritage Features Present at Onion Ridge Potential Natural Area Preserve (Washington Department of Natural Resources, 2018)

NHP Plan Element Plant Associations Priority Representation within natural areas

Ecosystem Elements

Douglas-fir / Mallow-leaf Ninebark Forest

Pseudotsuga menziesii / Physocarpus malvaceus Forest (G5S3)

* (see note

below table)

Baird Basin RNA, Dishman Hills NRCA, Maitlen Creek RNA, Spring Creek Canyon NAP, Wenaha Breaks RNA, Trombetta Canyon NAP

Douglas-fir / Mallow-leaf Ninebark – Twinflower Forest

Pseudotsuga menziesii / Physocarpus malvaceus - Linnaea borealis Forest (G4S4)

3 Trombetta Canyon NAP, Maple Mountain PRNA

Idaho fescue / Parsnip-flowered Buckwheat Grassland

Festuca idahoensis - Eriogonum heracleoides Herbaceous Vegetation (G2S2)

2 Ragged Ridge NAP, Maple Mountain PRNA

Mid-elevation Freshwater Wetland

Alnus incana / Cornus sericea Wet Shrubland (G3G4S3)

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Dailey Prairie NAP, Goat Marsh RNA, Little Pend Oreille River NAP, Mount Pilchuck NRCA, Mount Si NRCA, Steamboat Mountain RNA, Trout Lake NAP, Thirteen Mile Ponds PRNA, Hall Ponds PRNA

Eleocharis palustris Marsh (G5S3?)

Carex cusickii Fen (G3S2S3)

Carex lasiocarpa Fen (G4?S3?)

Carex utriculata Rocky Mountain Marsh [Provisional] (GNRSNR)

Cornus sericea Rocky Mountain Wet Shrubland (G4QS2S4)

Typha latifolia Western Marsh (G5S4)

Mid-elevation Permanent Pond n/a 2 Goat Marsh RNA, Pyramid Lake RNA, Steamboat Mountain RNA, Cedar Creek PRNA, Bunchgrass Meadows RNA

Western Redcedar / Wild Sarsaparilla Forest

Thuja plicata – Asarum caudatum Forest (G2S2) 2

Plant Species Element

Bulb-bearing water hemlock (Cicuta bulbifera (G5S2S3))

n/a 3 Fish Lake Bog RNA;

Priority Status * indicates the element is no longer a priority for inclusion in the statewide system of natural areas. However, this designation for Douglas-fir / Mallow-leaf Ninebark Forest is based on

the assumption that the Onion Ridge occurrence is protected.

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Vegetation

Forests cover the majority of the pNAP. Late seral stage, fire-initiated stands constitute the majority of

forests. Douglas-fir (Pseudotsuga menziesii) and western larch (Larix occidentalis} are the major tree

species in the canopy, although western redcedar (Thuja plicata), grand fir (Abies grandis), ponderosa

pine (Pinus ponderosa} and lodgepole pine (P. contorta) are important in localized areas. The site also has

a diverse hardwood component. Quaking aspen (Populus tremuloides) grows in pockets on Grande

Mountain's slopes and frequently appears near ponds with black cottonwood (Populus trichocarpa), paper

birch (Betula papyrifera) and thinleaf alder (Alnus incana).

The majority of the forests at Onion Ridge are classified as the Douglas-fir/ Mallow-leaf Ninebark Forest

and Douglas-fir / Mallow-leaf Ninebark-Twinflower Forest associations (Figure 7). These forests are found

over most of the area, but are concentrated on the broad northwesterly slopes of Grande Mountain. The

portion of the 1991 pNAP boundary that was excluded in the 2020 pNAP boundary mostly consists of

these two forest communities. These forests mostly consist of mid to late seral communities with mixed

canopy stands of Douglas-fir, western larch, and minor amounts of lodgepole pine. These forests are

structurally complex, both vertically and horizontally. The dominant conifer canopy is composed of trees

around 100 years old with trunk diameters between 10-14 inches. Larger diameter (24-36 inches)

ponderosa pine, western larch and Douglas-fir trees are scattered throughout (Figure 8). Tree

regeneration is patchy and varies with the local environment. Douglas-fir is the most common seedling. It

appears to be invading the more xeric environments and dominates canopy gaps in most forest stands. A

shrub layer of mallow-leaf ninebark (Physocarpa malvaceus) usually dominates the understory. Ninebark

forms thickets with other shrub species, such as mountain maple (Acer glabrum), buffaloberry

(Shepherdia canadensis), oceanspray (Holodiscus discolor), and serviceberry (Amelanchier alnifolia).

Shorter shrubs, whose abundance varies with environment, are Oregon boxwood (Pachistima myrsinites),

baldhip rose (Rosa sp.), thimbleberry (Rubus parviflorus), common snowberry (Symphoricarpus albus},

white spiraeae (Spiraea betulifolia), and tall Oregon grape (Mahonia aquifolium). The most common

understory combination is a patchy, 5 to 7-foot tall layer of mallow-leaf ninebark with a less than one-

foot tall, broken layer of Oregon boxwood and patches of pinegrass and western fescue (Festuca

occidentalis). Twinflower (Linnaea borealis) occurs near moist areas as part of the lowest vegetation layer.

It appears occasionally with big huckleberry or dwarf huckleberry (Vaccinium membranaceum and V.

caespitosum) shrubs. Near transition areas between these forests and drier sites, the tall shrub layer thins

and pinegrass with an increasing abundance of heart-leaved arnica (Arnica cordifolia) and false-Solomon

seal (Maianthemum stellatum) increases.

Snags are concentrated in and around the ponds, but occur across the whole area. Larch is the most

common snag, although western redcedar snags are abundant in some ponds. Down large woody debris

is frequent on site. Beaver have contributed trees to the woody debris component by felling large

diameter black cottonwood and some conifers away from ponds.

Forest communities on flat to concaves sites, moist draws, and adjacent to wetlands often support the

Western Redcedar / Wild Sarsaparilla Forest (Figure 9). In these areas, western redcedar forms thickets

of saplings, closed canopy trees 12-18 inches in diameter, and other stands have a diversity of size

diameters. Larger individuals are nearly 24 inches diameter, although trees less than 10 inches are most

common. Western larch, 18-30 inches in diameter, are scattered within and above some of these stands

as snags

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Figure 6. Topography of the Onion Ridge Potential Natural Area Preserve.

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Figure 7. Douglas-fir / Mallow-leaf Ninebark Forest Association.

Figure 8. Large diameter trees are scattered across the site.

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Figure 9. Western Redcedar / Wild Sarsaparilla Forest Association.

or dying individuals. Older trees usually have charcoaled bark or fire scars. Western redcedar seedlings

are by far the most common seedlings although grand fir seedings may be observed. The understory can

vary from having very little herbaceous or shrub cover to being composed of mesic species, such as wild

sarsaparilla (Aralia nudicaulis) and queenscup beadlily (Clintonia uniflora). These moist site forest stands

are individually small and collectively occupy approximately 50 acres. Near wetlands, western redcedar

mixes with paper birch, black cottonwood, grand fir and, near one pond, Engelmann spruce (Picea

engelmannii).

Grand-fir forest associations also occur in moist areas, often at toe or shelter slopes. These areas support

seral stands of the Grand Fir / Queenscup Beadlily or the Grand Fir / Mallow-leaf Ninebark forest

associations. These stands are currently dominated by Douglas-fir and western larch with scattered grand

fir dominating regeneration and occasionally present in the overstory. Despite being represented at the

site, they were too small to be considered a Priority element at the pNAP.

The most xeric sites occur on areas with exposed granite bedrock, on the peaks of O’Toole and Grande

Mountains, and on the steep westerly to southwesterly aspects above Phalon Lake valley. Lichen covered

rock grades into thick layers of mosses and Selaginella on large exposed granite rocks (Figure 10). These

mossy carpets often provide substrate for a variety of annuals, such as winter bentgrass (Agrostis scabra)

and sheep sorrel (Rumex acetosella). The mossy carpet typically grades into grassy, irregularly shaped

communities growing on benches and concave microsites. The Idaho Fescue-Parsnip-flowered Buckwheat

Grassland Association is found on deep soils in these areas (Figure 11). These grassland are best

represented on the summit north of O'Toole Lake. Idaho fescue (Festuca idahoensis), bluebunch

wheatgrass (Pseudoroegneria spicata), and junegrass (Koeleria macrantha) dominate these sites. Forbs,

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such as arrowleaf balsamroot (Balsamorhiza sagittata), prairie smoke (Geum triflorum), hawkweed

(Hieracium spp.) and the low shrub, parsnip-flowered buckwheat (Eriogonum heracleoides) frequently

appear with the bunchgrasses. In close proximity to the grassland balds, an open canopy of either or both

Douglas-fir and ponderosa pine with a bluebunch wheatgrass understory is often found (Figure 12). These

areas represent the Ponderosa Pine-Douglas-fir / Beardless Bluebunch Wheatgrass Woodland Association

which is found on the steep slopes above Phalon Lake, and surrounding Grande and O'Toole Mountains.

On more protected sites, pinegrass (Calamagrostis rubescens) replaces the bunchgrasses and dominates

the understory with scattered short mallow-leaf ninebark shrubs. The Douglas Fir / Pinegrass Woodland

Association is represented in these areas as limited transitional stands between grassland balds on broad

ridges and other forest types. A widely spaced tree canopy of Douglas-fir or ponderosa pine may appear

over the pinegrass.

A cluster of ponds dot the northeastern corner of the pNAP. Wetlands and ponds account for

approximately 40 acres. Portions of these ponds are confined by steep granite walls with only a few flat

shorelines. Beaver dams have raised the water level in all seven of the ponds with outlets. Most of these

ponds contain stands of flooded snags and scores of floating logs. Steep shorelines and beaver activity

have limited wetland development. The five ponds without outlets may or may not have beaver use, but

all have developed emergent wetland vegetation.

Figure 10. Moss and lichen covered rock outcrops

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Figure 11. Idaho Fescue / Parsnip-flowered Buckwheat

Figure 12. Douglas-fir / Ponderosa Pine / Bluebunch Wheatgrass Forest Association.

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Wetland vegetation is limited to a narrow fringe around most ponds and to partially or shallowly

submerged logs. A shoreline fringe composed of tall shrubs, thinleaf alder (Alnus incana) and red-osier

dogwood (Cornus stolonifera), form a tangle below scattered trees of black cottonwood, paper birch,

and/or western redcedar. These areas are classified as the Alnus incana / Cornus sericea Wet Shrubland

(Figure 13). The Cornus sericea Rocky Mountain Wet Shrubland occurs along a riparian area below a

beaver dam that drains into a deep slot canyon in the south-central portion of the pNAP. The stream

channel in this area falls down a 30% slope channel filled with large rocks and an abundance down large

and branch woody debris and in only about 10-20 m wide.

Gray sedge (Carex canescens), soft-leaved sedge (C. disperma), and mannagrasses (Glyceria borealis, G.

grandis, and G. striata) rim the ponds by alternating with or occurring under the shrub thickets. Northern

clustered sedge (C. arcta) dominates the clumps of vegetation on downed logs. O'Toole Lake, the largest

of the ponds, has a floating mat (0.5 acre) that is co-dominated by the Carex lasiocarpa Fen association

and Carex utriculata Rocky Mountain Marsh association (Figure 14). The Carex cusickii Fen association

occurs around the a few pond edges on sapric peat. Beaked sedge (C. vesicaria), retrorse sedge (C.

retrorsa), northern mannagrass (Glyceria borealis), common spike-rush (Eleocharis palustris) and hemlock

water parsnip (Sium suave) form the emergent wetland communities in the shallows of ponds without

outlets (Figure 15). The Eleocharis palustris Marsh association is found in these areas. The Typha latifolia

Western Marsh association is present and can be locally dominant in many of the wetlands. Aquatic plants

observed in the ponds include populations of duckweed (Lemna sp.), water-lily (Nuphar polysepala),

bladderwort (Utricularia sp.), white water crowfoot (Ranunculus aquatilis) and pondweed (Potamogeton

spp.) (Figure 16).

Wildlife

Data from the Washington Department of Fish and Wildlife’s CHAT tool (Crucial Habitat Assessment Tool)

indicates that the Columbia spotted frog (Rana luteiventris), which is a Species of Greatest Conservation

Need and a State Candidate, has been observed in the wetlands at the pNAP and nearby Phalon Lake.

Dusky Grouse (Dendragapus obscurus), Pacific tree frog (Pseudacris regilla), and painted turtle (Chrysemys

picta) records also occur in the hexes that overlap with the pNAP (Figure 17). The latter two species were

also noted in the 1991 recommendation as being observed at the site. The pNAP also occurs a few miles

west of the Smackout Wolf Pack range.

During a 2008 visit, the author observed a moose in O’Toole Lake. Other animals noted as being observed

in the 1991 recommendation include turkey vultures (Cathartes aura), Canada geese (Branta canadensis),

mallards (Anas platyrhynchos), wood duck (Aix sponsa), red-tail hawk (Buteo jamaicensis), pileated

woodpecker (Dryocopus pileatus), nighthawk and numerous unidentified songbirds and insects. Deer,

bear, and beaver activity have been observed.

Condition

Ecological integrity of the forest, bald, and wetland vegetation communities are very good to excellent.

Forest communities show no evidence of logging or past grazing. Only a few stumps were observed near

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Figure 13. Alnus incana / Cornus sericea Wet Shrubland

Figure 14. Floating mat supporting Carex lasiocarpa Fen and Carex utriculata Rocky Mountain Marsh

associations at O’Toole Lake.

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Figure 15. Carex vesicaria, C. retrorsa, and other graminoids dominate many of the wetlands.

Figure 16. Aquatic vegetation is found in most ponds.

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Figure 17. Hexagons from Washington Department of Fish Wildlife’s CHAT tool and Onion Ridge pNAP

2020 boundary.

the easternmost boundary of the pNAP. Beaver-felled trees and deer, beaver, and geese browsing are the

only evidence of direct vegetation manipulation. The forests are natural second growth that regenerated

following fire. There are residual trees and snags from the forests that pre date the last stand replacement

fire approximately 100 years ago. These residual ponderosa pine, western larch and Douglas­ fir are found

on open dry forest sites and near the ponds. Large woody debris is present and is increasing on the forest

floor as the stands age.

There is some evidence of past livestock grazing in the open forests and in the bunchgrass communities.

St. John’s wort (Hypericum perforatum) grows in almost all dry sites. The scattered presence of Bromus

tectorum and B. mollis may indicate past grazing. However, despite the apparently past grazing stress, the

current cover, diversity, and vigor of native bunchgrasses, mosses, and lichens in the grassland are

indicative of a high-quality ecosystem. Clint Williams (personal communication, retired USFS Area

Ecologist) speculates that the ridge was part of a sheep drive prior to the 1930's but has receive little

impact since.

In 1991, NHP ecologists referenced a few trails near some of the ponds, as well as an old fire ring near

Lake O'Toole. These trails and the fire ring were not encountered during NHP’s 2019 field visit.

The northeastern-most pond in the pNAP has an abundance of reed canarygrass (Phalaris arundinacea),

common bentgrass (Agrostis capillaris) and Canada thistle (Cirsium arvense). There are fence posts around

the deepest portion of the pond, probably reflecting the pond level during drier times. The other ponds,

including O'Toole, have very few exotic species or signs of grazing. No human or livestock trails were

observed around any of the ponds. Beaver and Canada geese have altered the shoreline vegetation. Bitter

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nightshade (Solanum dulcamara) and Canada thistle are common on beaver dams but rarely seen

elsewhere. Speedwell (Veronica sp.} and Kentucky bluegrass (Poa pratensis) are found along the shore of

O'Toole Lake and other ponds that apparently are heavily used by geese.

The aquatic environment appears to be in good condition. There are no algal blooms indicative of

eutrophication and no exotic plants. O'Toole Lake was fishless until rainbow trout were stocked in 1940

(Wolcott 1963). The current status of fish in the pond is unknown.

Current Use

There is no evidence of regular human use of the pNAP. The lack of publically accessible roads into the

site limit any human use of the site. The area was inaccessible by road prior to November 1990 when a

new logging road was constructed to the northeast corner of the pNAP. DNR Northeast Region has timber

sales planned for the areas that were removed from the 1991 pNAP boundary (Figure 3 vs Figure 4). It is

possible the area is occasionally used for hunting but no signs of such activity were observed.

Other Known Examples

All of the forest priority elements represented on the pNAP occur on the Colville National Forest, Colville

Reservation, and other state and private lands, although only in a few areas with explicit protection from

logging or other stressors.

The Priority 2 Western Redcedar / Wild Sarsaparilla Forest is not protected at any other natural areas in

the state. The example of this forest type at Onion Ridge is among the best known in the state.

The Douglas-fir / Mallow-leaf Ninebark – Twinflower forest type is a Priority 3 element and is located

within the Maple Mountain Proposed Research Natural Area on the Okanogan-Wenatchee National

Forest. The example of this forest type at Onion Ridge is among the best known in the state. The Douglas-

fir / Mallow-leaf Ninebark Forest is protected in four established natural areas and four potential natural

areas (including Onion Ridge) in eastern Washington. The 2018 NHP Plan indicates this element is

adequately protected within the Canadian Rockies ecoregion, however that designation is based on the

assumption that Onion Ridge remains protected. Without the protection of the pNAP, the element would

be changed to Priority 3. The example of this forest type at Onion Ridge is among the best known in the

state. The 2020 pNAP boundary does not include as much acreage of these two forest types as was

included in the 1991 boundary. However, because these two elements are protected in other natural

areas and are very common on the landscape, they are a lower priority for protection at this site relative

to the other primary features.

The Priority 2 Idaho fescue / Parsnip-flowered Buckwheat Grassland is found on ridgetops or around rock

outcrops. These grasslands are currently protected at one natural area within Canadian Rockies ecoregion

and another potential natural area in the Okanogan ecoregion.

The Priority 2 Mid-elevation Freshwater Wetlands element is currently protected at one other site within

the Canadian Rockies ecoregion and protected within five established and two proposed natural areas in

other ecoregions across the state.

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The Priority 2 Mid-elevation Permanent Ponds are found in many of the wetland basins in the site. Some

of the ponds have aquatic vegetation around their perimeter and all have wetland communities (i.e., the

Mid-elevation Freshwater Wetland element) around their edges. These ponds are protected at four

established and one proposed natural areas across the state.

Preserve Design

Onion Ridge pNAP would provide protection for numerous priority elements listed in the 2018 NHP Plan

(Washington Department of Natural Resources 2018). The 1991 pNAP boundary was delineated to

account for protection of the wetlands, balds, and to include a large core forest area (Figure 1). The 2020

pNAP boundary is focused on protecting the balds and the watersheds of the numerous ponds and

wetlands found in the preserve (Figures 4 and 6). The boundaries are drawn to protect hydrologic units,

to create a large enough area to keep the area isolated and inaccessible, and to use as many natural

barriers as possible. The boundary generally follows the watersheds of all the ponds, the ridgeline running

from Section 9 south through sections 16, 21, and 28, and land that will buffer the core area from adjacent

land use.

The pNAP is continuous with forests managed for commercial timber and areas with interspersed livestock

operations and residences. Three logging roads approach the site from the Onion Creek side, none enter

the area. All are lightly used, almost exclusively by the land owners and their forest operations. DNR will

be using some of these roads for planned timber sales in the areas originally included in the 1991 pNAP

boundary. A road parallels the North Fork of Bruce Creek that branches west down to the Columbia River

and east to enter the Onion Creek drainage north of O'Toole Mountain. This road is closed by the land

owner at the north and southwest entries. Access from the northeast is unknown.

Current livestock operations in the Onion Creek area are apparently confined to pastures one-half mile to

the east. The closed forests along the east boundary have been adequate barriers to livestock movement

on to the ridge.

Any effects of fragmentation are most likely to result from altered fire frequency, potential fire

suppression impacts, loss of connectivity with other forests, and isolation in the landscape.

Management Considerations

Although the pNAP has management challenges, these are remarkably few considering the size of the site.

Poor road access (until recently) has allowed the area to retain excellent ecological integrity. Following

timber harvest activities the three roads mentioned previously should be closed where they enter DNR

lands. The roads should then be monitored for invasive species, especially plumeless thistle (Carduus

acanthoides), which is abundant along the entry road further to the east, and St. John’s wort which is

already abundant along the road. The closed roads will need yearly field inspection for, and potentially

control of, invasive species. The presence of St. John's wort should be monitored and may require control.

Given the abundance of invasive species in the northeastern-most pond, especially reed canarygrass, it

should be assessed for potential invasive plant control and restoration.

The Washington Department of Wildlife will be informed of the management objectives of the site so they

can assist with periodic site inspections. Stocking the lakes and ponds with fish should not occur.

References

Alt, D.D. and D.W. Hyndman. 1984. Roadside Geology of Washington. Mountain Press Publishing

Company. Missula, MT. 282p.

Stoffel, K.L., N.l. Joseph, S. Zurenko Waggoner, C.W. Gulick, M.A. Korosec, and B.B. Bunning. 1991.

Geologic Map of Washington- Northeast Quadrant. Div. Geol. and Earth Sci. Washington Dept. Nat. Res.

Geologic Map GM-39.

Washington Department of Natural Resources. 2018. State of Washington Natural Heritage Plan 2018.

Olympia, WA. 32 pp. Online: https://www.dnr.wa.gov/publications/amp_nh_plan_2018.pdf?6qjvm

Williams, C.K. and T.R. Lillybridge. 1989. Forested Plant Associations of the Colville National Forest -DRAFT.

USDA Forest Service PNW Region. R 6.

Wolcott, E.E. 1964. Lakes of Washington, Volume 2 Eastern Washington. Div. Water Resources Water

Supply Bulletin 14. 650p.

Prepared by: Current version prepared by Joe Rocchio (March, 27 2020; revised on June 4, 2020) and

is an updated and modified version of the September 8, 1991 recommendation prepared by Rex C.

Crawford and Reid Schuller.