Weber State University
Weber State University
Department of Botany
Antelope Island Field Trip
Plant Communities
Twelve plant communities are defined. Three are
limited to the Bonneville Basin. The others are found along the Wasatch
Range, the Back Valleys, and Eastern Highlands with some types being present
on Antelope Island. Seven hundred and ninety-eight species and/or subspecific
taxa are delineated.
Saline Marsh
Immediately adjacent to and/or part of the eastern edge
of the Great Salt Lake lies a saline marsh community. Elevations range
from 4200 to 4300 feet. The ground is essentially flat and covered
throughout much of the year with shallow, brackish water.
Cattails and tules are the dominant emergent vegetation,
while pond weeds and smart weeds are to be found floating in most areas of
standing, open water. Open flat lands are often covered with goosefoot.
Important plants are: Scirpus acutus,
Scirpus maritimus,
Typha domingensis, Typha latifolia, Salicornia rubra, Eleocharis palustris,
Carex nebraskensis, Carex aquatilis, Polygonum amphibium, Polygonum convolvulus,
Polygonum persicaria, Polygonum punctatum, Potamogeton pectinatus, Conium
maculatum, Distichlis spicata, Solanum dulcamara, Polypogon monspielensis.
Salt Desert Shrub
Upland from and often adjacent to the saline marsh area
is a region with a drier, clay, alkaline soil. Elevations range from
4300 to 4400 feet. Greasewood-dominated flats and saltgrass meadows are
characteristic of the moist lowland portions of this habitat.
Slightly higher and drier sites support a mixture of saltgrass and woody
chenopods.
Important plants are: Sarcobatus vermiculatus, Allenrolfea
occidentalis, Atriplex confertifolia, Atriplex patula, Chenopodium album,
Kochia scoparia, Distichlis spicata, Bromus tectorum, Cleome serrulata.
Fire Modified Mixed Grass
Only the foothill areas of Antelope Island and Fremont
Island are defined as mixed grass. This community lies between 4200
feet and 4800 feet, and is characterized by dry sandy-rocky soil covered
with mostly annual grasses, these probably being perpetuated by recurrent
fire.
Important plants are: Bromus tectorum, Bromus diandrus,
Oryzopsis hymenoides, Atriplex confertifolia, Grayia spinosa, Abronia fragrans,
Sphaeralcea coccinea, Chrysothamnus nauseosus.
Big Sagebrush
Sagebrush-dominated plant communities are widespread over
much of the area on well-drained, sandy soils from the foothills of the Wasatch
Mountains to the high ridges of the Wasatch front range. Big sagebrush,
big rabbitbrush, and snakeweed dominate the lower elevations, while black
sagebrush and yellow rabbitbrush are found mostly at higher sites.
Important plants are: Artemisia tridentata, Artemisia
arbuscula, Artemisia ludoviciana, Gutierrezia sarothrae, Elymus trachycaulus,
Elymus triticoides, Chrysothamnus nauseosus, Chrysothamnus viscidiflorus,
Bromus japonicus, Bromus tectorum.
Juniper
Stands of juniper are infrequent, small in size, and most
often found on moderate-to-steep south- or west-facing slopes between 5500
and 6500 feet. Soils in this type are shallow, sandy to rocky, dry,
and well drained. Utah juniper and western red cedar are the dominant
plants with curl leaf mountain mahogany and gambel oak also frequently found.
Important plants: Juniperus osteosperma, Juniperus
scopulorum, Artemisia tridentata, Quercus gambelii, Sporobolus airoides,
Oryzopsis hymenoides, Oenothera pallida.
Mixed Mountain Brush
This is the largest plant community. It is found
on almost all east-, west-, and south-facing exposures at elevations of 4600
to 7500 feet, and on north-facing exposures at lower elevations. Oak,
maple, and mahogany are the dominant plants. Soils are generally dry,
shallow on the rocky slopes or deep on flat area and in basin. Slopes
are moderate to steep.
Important plants are: Quercus gambelii, Acer grandidentatum,
Cercocarpus ledifolius, Acer glabrum, Prunus virginiana, Physocarpus malvaceus,
Purshia tridentata, Amelanchier utahensis, Berberis repens, Holodiscus dumosus,
Hydrophyllum capitatum, Allium acuminatum.
Riparian
A diverse riparian habitat is found throughout the area
in all canyons that contain perennial streams at elevations from 4200 to
9000 feet. The diversity of this habitat is in part a function of elevation,
hence this type is subdivided into three often overlapping areas: (1) high
elevations above 8000 feet, (2) middle elevations between 6000 and 8000 feet,
and (3) low elevations below 6000 feet.
High elevation riparian. This community generally
originates in a basin or meadow area. It is typified by dense stands
of perennial forbs, sedges, perennial grasses, and willows. Soils are
wet to damp, deep and dark. Streams are usually small, slow moving
and contain silty bottoms.
Important plants are: Salix bebbiana, Salix geyeriana,
Salix scouleriana, Rhamnus alnifolia, Habenaria dilatata, Scirpus microcarpus,
Catabrosa aquatica, Mimulus lewisii, Juncus longistylus, Juncus ensifolius,
Carex praegracilis, Alopecurus aequatis, Glyceria grandis.
Middle elevation riparian. At lower elevations the
canyons steepen and the volume and velocity of the streams increase.
Canyons are often deep and V-shaped. Streamsides and bottoms are often
rocky with little soil depth. Streams are usually bordered by tall
shrubs such as dogwood. Habitiat for grasses, forbs, and sedges is
generally reduced.
Important plants are: Cornus stolonifera, Salix
rigida, Acer grandidentatum, Amelanchier alnifolia, Rubus parviflorus, Clematis
columbiana, Ranunculus sceleratus, Senecio serra, Cardamine cordifolia, Carex
rostrata.
Low elevation riparian. At lower elevations the
streams are generally slower, wider, and often with large flood plains.
Here the soils are usually deeper and more productive. Such sites are
dominated by cottonwood, birch, and willow, with a mixture of forbs and grasses.
Important plants are: Populus angustifolia, Betula
occidentalis, Salix exigua, Acer negundo, Crataegus douglasii, Alnus tenuifolia,
Smilacina stellata, Smilacina racemosa, Steironema ciliatum, Carex lanuginosa,
Juncus bufonius.
History of Botanical Exploration
On September 6, 1843, Captain John C. Fremont on an assignment
to connect the interior land surveys made by the Wilkes expedition in 1841
camped on the Weber River Delta in present Weber County. The next morning
he set out for an island in the Great Salt Lake, later to be called Fremont
Island, but which he referred to as "Disappointment Island." He collected
plants there for two days then returned to the Weber River Delta where on
September 9, additional plants were collected. These collections were
the first to be made the purpose of scientific inquiry from this area.
Included were Atriplex canescens, Atriplex confertifolia, and Chrysothamnus
nauseosus. They were later sent to John Torrey of Columbia University.
In 1857 Jane Carrington made a collection of plants from
the "Salt Lake Area." These were later given to Elias Durand at the
Academy of Natural Sciences in Philadelphia. Using this collection,
and those of Fremont and Stansbury, Durand wrote the first local flora for
Utah entitled, "A sketch of the botany of the basin of the Great Salt Lake
of Utah."
In 1860 Sereno Watson traveling with the King exploration
of the fortieth parallel explored the mountains of the study area and the
islands of the Great Salt Lake. The results of this effort were published
by Watson in 1871 as Part Five of the "Report of the geological exploration
of the fortieth parallel." Watson's contribution was of great value
and consequence. The number of new species he discovered is staggering.
During this period 1843-1869 other botanists were also
in the area. In 1845 Joseph Burke, a collector from England traveled
through the area. In 1854, Lieutenant Edwin O. Beckwith while re-surveying Stansbury's old route passed through the area. And, in 1871 John C.
Coulter was in Northern Utah. Little is known of their collections
(if any) from this area.
The only other botanists who have contributed to an understanding
of this flora are Francis W. Pennell, and A. O. Garrett. Francis W.
Pennell of the New York Botanical Garden collected several species from this
area as recorded in his publication on the "Scrophulariaceae of the Rocky
Mountain States." A.O. Garrett, while head of the Biology Department
at East High School collected many plants from the southern Wasatch Mountains.
The most recent collections have been made by this writer,
who from 1965 to the present has collected extensively in the area.
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