Distribution of Plant Communities and Composition of Plant Species in the Blue Mountains: Johnston Wilderness Area

Andrea Lee Freng

A thesis submitted in partial fulfillment for graduation in Biology

Whitman College

2003

TABLE OF CONTENTS

Abstract

Introduction

Methods

Results

Discussion

Acknowledgements

Literature Cited

Color Photos

LIST OF ILLUSTRATIONS

Tables

Table 1. List of plants

Table 2. Number of taxa observed in the three major plant groups

Table 3. Relative abundance in each of the six plant communities

Figures

Figure 1a and 1b. Road map and aerial photo

Figure 2. Aerial photo with paths in red

Figure 3. Distribution of the 123 vascular plant species among 37 families

Figure 4. Aerial view of the six different plant communities

Figure 5. Distribution of families and species among the plant communities

Figure 6. Percentage of total species in each of communities that were non-native

DISTRIBUTION OF PLANT COMMUNITIES AND COMPOSITION OF PLANT SPECIES IN THE BLUE MOUNTAINS: JOHNSTON WILDERNESS AREA

ABSTRACT

Little is known about the flora of the Whitman College Johnston Wilderness area, located on Mill Creek in the foothills of the Blue Mountains in Oregon. To determine the composition of plant species and document how species composition varies between communities within the 26-acre property, a survey of the plants was conducted from April to October 2002. Roughly 123 species of vascular plants were collected and identified. The number of species in the six different communities ranged from ten to nearly 70, with the cabin grounds community being the most diverse. Among the different plant families, Rosaceae had the most species with eighteen collected. Of the plants identified to species level, 37 were non-native, comprising roughly 30% of all the species collected. Two invasive, non-native species that should be placed on red alert are Polygonum cuspidatum (Japanese Knotweed) in the Cabin Grounds community and Centaurea solstitialis (Yellow Star Thistle) in the Grassy Slope community. It is imperative that follow-up studies be conducted to determine immediate methods to rid the area of these noxious weeds.

INTRODUCTION

The Whitman College Johnston Wilderness Campus (JWC), donated to the college in 1998 by Stuart and Joyce Johnston, rests between Mill Creek and the Umatilla National Forest in the foothills of the Blue Mountains. The property encompasses 26 forested acres, including several cabins, a riparian habitat, north and south-facing slopes, as well as several other microhabitats. The previous owners utilized the property as a hunting lodge and vacation retreat during the summers. Since its acquisition of the property, Whitman College has renovated several of the cabins and constructed an environmental studies classroom. The Environmental Studies and science classes at Whitman currently utilize the area for field trips, natural history research, environmental studies projects, and as a teaching lab. Because the area is also used for retreats and meetings, the current management practices in the cabin grounds frequently mimic that of a park. In order to document the biota of the area and to properly manage them (with minimal disturbance), we need a clear assessment of the organisms that occur; the status of plants and animals needs evaluation.

In the summer of 2001, Nicholas W. Griffin (Griffin 2002) conducted a faunal survey of the area in which he collected or observed over 60 invertebrate and 45 vertebrate animal species. With the knowledge of his study, Griffin made verbal management recommendations to Whitman College at the 2002 Whitman College Undergraduate Conference, especially with regard to amphibian habitats near Mill Creek and around small ponds and ditches in the main cabin area. A similar survey of the plants of the area seemed the next logical step in assessing the biota of the area.

Few studies of vascular plants in the Blue Mountain have been undertaken. In 1992, Sara Blattler (Blattler 1992) conducted a survey of the Whitman College Cabin, located 1 mile from the JWC. Shortly after Whitman College acquired the JWC property, two students did a basic study of the area’s plants3 that are useful to humans. Although both of these projects gave some idea of the plants to be found in the area, they were incomplete and did not address the different plant communities. The purpose of this study contained three main parts 1) to survey the plants and compile a more complete list of vascular plants found at the Johnston Wilderness Campus area and to collect voucher specimens to deposit in the Whitman College Herbarium, 2) to identify plant communities and compare them in terms of species compositions, and 3) to document the presence of non-native species (with an emphasis on identifying potentially problematic invasive weeds).

METHODS

Study Site

This study was conducted from April to October of 2002 at the Whitman College Johnston Wilderness Campus area, located in the foothills of the Blue Mountains on Mill Creek Road south of Kooskooskie, Oregon, USA (45°59’ N, 118°04’ W, elev. ~2280ft./ 695m.).

A road map and aerial photo are shown in Figure 1. The site is very heterogeneous, resting between Mill Creek Rd. and a grassy ridge that borders Umatilla National Forest. The entrance to the cabin is flat and contains many trees. Much of the property consists of coniferous forest. A wide variety of vertebrate and animals can be observed at the site. The land on either side of the property is privately owned and primarily serves as summer vacation spots for families. There is a swimming hole area of Mill Creek at the northeast area of the property where a flood in the early 1990s widened the banks. Salmon were seen in this area during the summer of 2002.

Plant Collection and Identification

Only visibly flowering, cone-bearing, or spore-producing plants were collected because of the necessity of reproductive structures for identification to the species level. Additionally, only plants that were accessible by trails were collected. Ornamentals, with the exception of prolific weeds, were omitted from the collection. Plants were collected during weekly walks that followed a route of trails (see Figure 2). The walks followed pre-established man-made or animal paths through the survey site, which consisted of approximately 7 of the 26 acres of the property (see Figure 1). Almost all plants were identified to family, genus, and species levels with the use of dissecting scopes, guide books (Lyons 1997, Whitson et al. 1996, Strickler 1993,

Figure 1a. Road map of the Whitman College Johnston Wilderness Area and surrounding area. The approximate location of the cabin grounds is indicated by a star. (Map is oriented so that North is at the top).

Figure 1b. Aerial photograph of the Johnston Wilderness Area. (Photograph is oriented so that North is at the top).

Figure 2. Aerial photograph with route of trails in red. (Photograph is oriented so that North is at the bottom).

Taylor 1992, Taylor 1990), and dichotomous keys (Hitchcock and Cronquist 1973, Hitchcock et al. 1961). Experienced taxonomists were consulted in the identification for a few specimens (Datwyler 2002). In addition to cataloging the species and looking for patterns and trends among communities, positively identified species were organized into the categories of native and non-native, according to Vascular Plants of the Pacific Northwest (Hitchcock et al. 1961). Photographs were taken of most species in their native habitats with a Canon digital camera.

Voucher specimens were collected for each species and are deposited in the Whitman College Herbarium in Walla Walla, WA.

Plant Communities

The boundaries of the plant communities were subjectively defined based on vegetative features, levels of light and moisture, and on the degree of human disturbance. Aerial photos (Umatilla National Forest 2002-2003) viewed under a mirror stereoscope were also used to more accurately draw the boundaries of the six communities identified. Each community was characterized in terms of floristic composition and representation of native and non-native species.

RESULTS

Species Composition

All the individual species recorded are listed by family in Table 1, and their native vs. non-native status indicated. A total of 123 species, comprising 37 vascular plant families, were recorded on the weekly walks. Note that of the species recorded, all 37 non-native species documented were angiosperms. All the recorded species can be categorized into three main plant groups: 1) the ferns and allies with a total of four species in two families, 2) the gymnosperms with six species in three families, and 3) the angiosperms with 113 species in thirty-three families (Table 2). The angiosperms were the dominant group and comprised 92% of species recorded. The most well-represented flowering plant families included, in order of decreasing species number: Rosaceae with eighteen spp., Fabaceae with eleven spp., Asteraceae with nine spp., Poaceae with eight spp., Scrophulariaceae with seven spp., and Liliaceae with six spp. For the gymnosperms, the most dominant family was Pinaceae, with four spp. Of the ferns and allies, Polypodiaceae was the most represented family with three species. Almost half of the families recorded were only represented by one species (see Figure 3). A total of 7 angiosperm species were not identified to family level.

Plant Communities

A total of six plant communities were defined within the area, based on qualitative observations. The limits of each community are shown in the aerial photo in Figure 4. These were the Cabin Grounds, Forest Path, Grassy Slope, Riparian, Disturbed Roadside, and the Forest communities.

Figure 4. Aerial view of the six different plant communities. The communities are outlined as followes: Cabin grounds – yellow, Forest Path – pink, Grassy Slope – brown, Riparian – blue, Disturbed Roadside – orange, and Forest – green. (Photograph is oriented so that North is at the bottom.)

Cabin Grounds Community (Yellow)

The Cabin Grounds community, which was the most heterogeneous of all the communities in appearance, was characterized by its flat topography, proximity to the cabins, and high level of human disturbance. The Cabin Grounds community was roughly the third largest community. This community contained well over 70 species from at least 33 families; about 41% of these were non-native. However, many ornamental trees, flowers, and lawn grasses were not collected in this community. Characteristic species in this community that were non-native include Polygonum cuspidatum (Japanese Knotweed), Lamium purpureum (Red Dead Nettle), and several Rosaceae species in the genus Rubus (blackberries, raspberries). Characteristic native species include Claytonia sibirica (Miner’s Lettuce), which was abundant in all communities except the Grassy Slope, Aruncus dioicus var. vulgaris (Goat’s Beard), which was also abundant in the Disturbed Roadside and Riparian communities. Psudotsuga menziesii (Douglas Fir) and the ferns were common in the Cabin Grounds community as well as in the Forest and Forest Path communities.

Forest Path Community (Pink)

The forest path community was situated within the Forest community and was characterized by an open canopy and therefore higher light levels. Approximately 40 species from 20 families were collected, of which 13% were non-native. Characteristic species in the Forest Path communities were all Pinaceae species (conifers), all Polypodiaceae species (ferns), and several Liliaceae species including Maianthemum stellatum (Star-flowered Solomon’s Seal), Maianthemum racemosum (False Solomon’s Seal), and Streptopus amplexifolius (Twisted Stalk).

Grassy Slope Community (Brown)

The grassy slope community was dry and windy with steep, south-facing slopes ascending to a ridge top that marked the beginning of the Umatilla National Forest property boundary. This was the second largest community. About 24 species from 16 families comprised this community, of which less than 13% were non-native. Grasses (in the Poaceae family) are very characteristic of this community as are Balsamorhiza sagittata (Arrowleaf Balsamroot), Allium douglasii (Wild Onion), Triteleia grandiflora (Brodiaea), and Lupinus sulphureus (Yellow Lupine).

Riparian Community (Blue)

The riparian community was located between the Cabin Grounds and Disturbed Roadside communities. This community was consistently moist due to the close proximity of Mill Creek and irrigation ditches. This was one of the smallest communities because it was restricted to areas at or near the creek. Fourteen families and nineteen species were collected; approximately 32% of the species in this community were non-native. Characteristic species included Populus angustifoilus (Cottonwood), Rubus parviflorus (Thimble berry), and Ranunculus spp. (Buttercup).

Disturbed Roadside Community (Orange)

The disturbed roadside community included the portion of Mill Creek Road that borders the Johnston Wilderness Campus and the road and driveway leading up to the gate of the property. This community was one of the smallest communities as well as the least collected due to the difficulty of obtaining specimens that were found on very steep drop-offs next to the road. This community was highly variable in degree of light and moisture from area to area. Although 21 species from 10 families were collected, there were more species not collected in this community. Over half of the species collected in this community are non-native. Characteristic species include many non-natives such as Lathyrus latifolius (Sweet Pea), Hypericum perforatum (St. John’s Wort), and Cirsium vulgare (Bull Thistle). A relatively abundant native was Aruncus dioicus var. vulgaris (Goat’s Beard).

Forest Community (Green)

The forest community was characterized by north-facing slopes, a dense canopy – resulting in lower light levels, moderate moisture levels from numerous springs and irrigation pipelines, and abundant vegetation comprised mostly of conifers, mosses, and ferns. This was the largest of all six communities, as well as the least explored. Of the five families and 10 species identified in this community, none were non-native. Conifers (in the Pinaceae family) and ferns (Polypodiaceae) were very abundant in this community. Characteristic angiosperms included Asarum caudatum (Wild Ginger) and Claytonia sibirica (Candyflower).

Distribution of Species throughout Plant Communities

As summarized in Figure 5, the distribution of the 37 families and 123 species among the plant communities, in order of decreasing number of families recorded, was the Cabin Grounds, Forest Path, Grassy Slope, Riparian, disturbed Roadside, and Forest community. The number of species recorded in each community followed the same decreasing order, except that the Disturbed Roadside community had more species recorded than the Riparian community. Table 3 summarizes the relative abundance of each plant identified to species in each of the six different plant communities. An example of a plant with relative abundance of 1 is a plant which was only seen in one small population, where a plant with relative abundance of 4 or 5 was commonly seen in high numbers throughout a given population. Plants with a high relative abundance tended to be weedy (P. cuspidatum) and/or spread through rhizomatous growth (P. cuspidatum, Maianthemum racemosum, Maianthemum stellatum, and Claytonia sibirica).

Native and Non-native Vegetation

Of the 123 species collected, at least 37 are non-native to the study site. In other words, over 30 percent of all species in the area are non-native. Figure 6 displays the percentage of plants that are non-native in each of the six plant communities. The Disturbed Road community contained the most non-native species with over 54% not native to this area. In the Cabin Grounds community, 40.6% of identified species were non-native. This number would increase substantially should all ornamentals be included. The Riparian community (situated between the two communities with the highest levels of disturbance) had the third highest percentage of non-native species, with 31.6% non-native species. The Forest Path and Grassy Slope communities both consisted of about 12.5% non-native species. No non-native species were encountered in the Forest community.

Two very invasive, non-native species recorded included P. cuspidatum (Japanese Knotweed) in the Cabin Grounds community, spreading towards the Forest Path and Riparian communities, and C. solstitialis (Yellow Star Thistle) in the Grassy Slope community.

DISCUSSION

The plant communities that I found were the Cabin Grounds community, Forest Path community, Grassy Slope community, Riparian community, Disturbed Roadside community, and the Forest community. The Cabin Grounds community was the most heterogeneous of all the communities, which contributes to its high species diversity. The Forest community, though the largest in size, had the lowest number of recorded species. However, most of the species that did occur, which included mostly conifers, ferns, and two angiosperm species, were all found in high relative abundance. It may be that the conditions of this community are ideal for a select group of plants. One characteristic of the Forest community was that it was situated on north-facing slopes, which receive less sun than do south-facing slopes.

Overall, I found 123 species in 37 different vascular plant families distributed among the six plant communities. Certain species of plants were clearly dominant in one community or another. These plants, which had high levels of relative abundance, included all Rubus species (blackberries, etc.), P. cuspidatum, Maianthemum racemosum, Maianthemum stellatum, and Claytonia sibirica, which all spread rapidly via rhizomatous growth or vigorous seed production. This collection does not represent all the species in the area. There are likely over 200 species in the Johnston Wilderness Campus area, but they were not observed or collected for several reasons.

The sampling methods used during this project served as likely contributors to a lower than expected collection number. Not all 26 acres were surveyed and only plants in areas accessible by paths and trails were collected. It would be useful to conduct a future study in which transects are systematically laid. This would, however, require a team of botanists, as this project was more than a full-time job at the level it was conducted. The incredible magnitude and importance of this project is reason to invite other budding botanists to locate and identify more plant species.

On previous visits to the area in other years, I saw plants blooming that I did not encounter (but specifically looked for) during my survey. The winter before the summer of this study was particularly long and harsh, which likely affected the success and rate of blooming. Another year would probably yield more blooms from different species as well as slightly different distribution patterns. Also, the area near the cabins is very manicured and planted. This undoubtedly affected the plants that I saw. For example, an area where Aquilegia sp. (Columbines) was observed in a different year was consistently mowed during the summer of my study. As native plant seeds sprout and are mowed before they have the chance to flower and set seed, the seed bank will eventually be depleted. Additionally, the recent bulldozing of topsoil and subsequent planting of lawn grass near the cabins likely upset the seed bank, resulting in fewer than expected wildflowers in the Cabin Grounds community.

It is necessary to address the issue of non-native species (especially Japanese Knotweed and Yellow Star Thistle) and the need for a follow-up study on controlling the spread of these noxious weeds. Centaurea solstitialis, or Yellow Star Thistle, is a rising problem in the Grassy Slope community and should be placed on red alert! Plants must be removed before they are allowed to flower, so they don’t “go to seed.” C. solstitialis is already a difficult invasive weed to control throughout the western United States and has taken over many grassy and pastured areas.

Polygonum cuspidatum (Japanese Knotweed), which was introduced to the United States in the late 1800s as an ornamental, spreads by rhizomes and is beginning to choke out native vegetation in moist areas. The Japanese Knotweed is currently found mostly only in the moist areas of the Cabin Grounds community, but in an effort to eradicate the species, the rhizomatous weed was innocently deposited in a “weed pile” at the base of a man-made path that leads into the Forest Path community. There is evidence that the weed is now quickly spreading via rhizomes (horizontal, underground stems) into the moist areas at the base of the Forest Path community to which this same man-made path leads. Small pieces of rhizomes are the likely culprits. The danger associated with P. cuspidatum is that it prefers moist, riparian areas (typically near creeks) where many animals have established themselves. Although pesticides have generally been ineffective at eradicating this weed, they are still used. Their use endangers the health of the fragile riparian communities, but allowing the weeds to grow chokes-out the native vegetation that is also such a vital part of the success of riparian ecosystems. Future research into safe methods of controlling the spread of P. cuspidatum are strongly encouraged.

Given the uses of the area, it is difficult to preserve the integrity of native vegetation, but must be attempted where possible if the biotic diversity and natural beauty of the area is to be preserved. Furthermore, it is imperative that the spread of particularly invasive weeds be immediately controlled and the growth of existing native vegetation encouraged so that the Johnston Wilderness Campus does not become a weed patch.

ACKNOWLEDGEMENTS

I would like to thank Dr. Delbert Hutchinson for his support, suggestions, and for his assistance obtaining funding through the Rall Summer grant. I thank my advisor Dr. Heidi Dobson for her support and assistance while writing this thesis and for her contagious enthusiasm for biology and botany while I have been a student at Whitman College. Heidi’s Plant Biology course kindled my initial interest in ecology and plant taxonomy and ultimately helped me decide to pursue a degree in biology and embark upon this thesis project. I also greatly appreciate all the assistance I have received from Martha Holt while at Whitman. I thank my parents for their contribution to my love of plants: Teri, my mom, for teaching me about house plants and for helping me with my first two plant collections when I was a child in grade school (thanks for staying up so late to help me finish identifying them the night before they were due!); Steven, my dad, for passing along his knowledge of the agricultural use of plants. I also thank Whitman College for allowing me to live in a cabin at the Johnston Wilderness Campus during the summer portion of my study and for renting me a car to drive between JWC and the Whitman College campus. Additionally, I thank Nick Griffin for taking me “batting” at JWC in the summer of 2001 while he completed his study of the area’s fauna and for informing me of President Cronin’s desire for a student to catalogue the plant life. I also appreciate the assistance and friendliness of the JWC caretakers, Marianne and Rich Piver. I thank Professor Bob Carson and Margo Burton for helping me obtain aerial photos from the Umatilla National Forest. Finally, I thank my friends who gave me moral support (and occasionally assistance with plant collecting) . . . there’s no way I would have made it through such a laborious project without their constant encouragement and support.

LITERATURE CITED

Blattler, Sarah. 1992. Trees and Flowers of the Blue Mountains. Walla Walla, Washington, USA: Whitman College.

Datwyler, Shannon(personal communication). April 2002. Whitman College.

Griffin, Nicholas W. 2002. A Field Guide to the Fauna of the Johnston Wilderness Campus. Whitman College Biology thesis.

Hitchcock, C. Leo, Arthur Cronquist, Marion Owenby and J.W. Thompson. 1961. Vascular Plants of the Pacific Northwest. Vol. 1-5. Seattle, Washington, USA: University of Washington Press:.

Hitchcock, C. Leo and Arthur Cronquist. 1973. Flora of the Pacific Northwest: An Illustrated Manual. Seattle, Washington, USA: University of Washington Press:.

Lyons, C.P. 1997. Wildflowers of Washington. Renton, Washington, USA: Lone Pine Publishing.

Strickler, Dee. 1993. Wayside Wildflowers of the Pacific Northwest. Columbia Falls, Montana, USA: The Flower Press.

Taylor, Ronald J. 1990. Northwest Weeds: The Ugly and Beautiful Villains of Fields, Gardens, and Roadsides. Missoula, Montana: Mountain Press Publishing Company.

Taylor, Ronald J. 1992. Sagebrush Country: A Wildflower Sanctuary. Missoula, Montana, USA: Mountain Press Publishing Company.

Umatilla National Forest, Aerial Photographs. 2002-2003. Obtained by Bob Carson, Whitman College.

Whitman College Environmental Studies Department http://www.whitman.edu/environmental_studies/WWRB/vegetation.html. 2003

Whitson, Tom D. ed., Larry C. Burrill et al. 1996. Weeds of the West. The Western Society of Weed Science in cooperation with the Western United States Lant Grant Universities Cooperative Extension Services. Jackson, Wyoming, USA: University of Wyoming,.

Color Photos of Specimens Taken

Ferns and Allies

POLYPODIACEAE Polystichum munitum (Kaulf.) Presl. Sword Fern

POLYPODIACEAE Pteridium aguilinum (L.) Duhn. Bracken Fern

SELAGINELLACEAE Selaginella spp. Beauv. Selaginella

Gymnosperms

PINACEAE Abies grandis (Dougl.) Lindl. Grand Fir

PINACEAE Larix occidentalis Nutt. Larch

CUPRESSACEAE Thuja plicata Don Western Red Cedar

Angiosperms

ARISTOLOCHIACEAE Asarum caudatum L. Wild Ginger

ASTERACEAE Achillea millefolium L. Yarrow

ASTERACEAE Arnica spp. Arnica

ASTERACEAE Cirsium vulgare (Savi) Tem. Bull Thistle (with Goat's Beard)

BERBERIDACEAE Berberis aquifolium Pursh Oregon Grape

BETULACEAE Alnus incana (L.) Moench Alder

BORAGINACEAE Lithospermum arvense L. Forget-Me-Not

CAPRIFOLIACEAE Linnea borealis L. Twin Flower

CAPRIFOLIACEAE Symphoricarpus albus (L.) Blake Snowberry

CARYOPHYLLACEAE unidentified

FABACEAE Lupinus leucophyllus Dougl. ex Lindl. Purple Lupine

FABACEAE Melilotus alba Desr. White Sweet Clover

FABACEAE Trifolium pratense L. Purple Clover

FABACEAE Trifolium repens L. White Clover

FUMARIACEAE Dicentra cucullaria (L.) Bernh. Dutchman's Breeches

HYPERICACEAE Hypericum perforatum L. St. John's Wort

LAMIACEAE Prunella vulgaris L. Common Mint

LILIACEAE Allium douglasii Hook. Wild Onion

LILIACEAE Clintonia uniflora (Menzies) Kunth. Queen's Cup

PORTULACACEAE Claytonia sibirica L. Candyflower

ROSACEAE Aruncus dioicus var. vulgaris (Maxim.) Hara Goat's Beard

ROSACEAE Rubus parviflorus Nutt. Thimbleberry

ROSACEAE Rubus procerus Muell. Himalayan Blackberry

ROSACEAE Spiraea betulifolia Pall. White Spiraea

ROSACEAE Spiraea douglasii var. menziesii (Hook.) Presl. Spiraea

SCROPHULARIACEAE Linaria gentisifolia (L.) P. Mill Dalmation Toadflax

SCROPHULARIACEAE Penstemon spp. Penstemon

SOLANACEAE Solanum dulcamara L. Bittersweet Nightshade

VIOLACEAE Viola glabella Nutt. Johnny Jump Up, Stream Violet

Angiosperms - Invasive Weeds!!!

ASTERACEAE Centaurea solstitialis L. Yellow Star Thistle

POLYGONACEAE Polygonum cuspidatum Sieb. & Zucc. Japanese Knotweed

Japanese Knotweed (Stem)