Endangered Plants and Ecosystems - The American Landscape
species pine percent forest
Although North America has less plant diversity than the tropics, it is nonetheless amazingly rich. The diverse environmental conditions found on the continent allow representatives of most of the world's major plant groups to flourish in one region or another. For example, North America is home to more than 211 flowering plant families alone. The richest assemblages of flowering plants are found in Florida and Texas.
Botanists have divided North America into a series of ecosystems based on the underlying vegetation. Northern coniferous forests make up 28 percent of the North American continent; grasslands, 21–25 percent; arctic ecosystems, 19 percent; eastern deciduous forests, 11 percent; coastal plain ecosystems, 3 percent; desert ecosystems, 5 percent; western mountain coniferous forests, 7 percent; tidal wetlands, 1 percent; Mediterranean scrublands and woodlands, 1 percent; and beach vegetation, less than 1 percent.
Endangered U.S. Ecosystems
In 1995 the first full review of the health of the American landscape, "Endangered Ecosystems of the United States—A Preliminary Assessment of Loss and Degradation," was compiled by the National Biological Service (NBS) and published by the U.S. Geological Survey. It is still considered the definitive study of U.S. ecosystem health. Although individual species had been studied previously,
TABLE 4.2 Endangered and threatened species of nonflowering plants, February 2004
the health of the larger ecosystems had never before been considered. The study was based on surveys of state databases and the scientific literature. The report concluded that vast stretches of natural habitat, totaling
FIGURE 4.1 Distribution of critically endangered, endangered, and threatened ecosystem types
nearly half the area of the 48 contiguous states, had declined to the point of endangerment. Ecosystems suffered in two ways. Quantitative losses were measured by a decline in the area of an ecosystem. Qualitative losses involved degradation in the structure, function, or composition of an ecosystem.
Of the ecosystems that had declined by over 70 percent, 58 percent were terrestrial, 32 percent were wetland areas, and 10 percent were aquatic. Forests, grasslands, barrens, and savannas dominated the list. (See Figure 4.1.) American ecosystems identified by the NBS as suffering the greatest
FIGURE 4.2 Extent of historical (pre-European) grass prairies on the North American Great Plains
overall decline include tall-grass prairies and oak savannas of the Midwest, deciduous forests of the East, and longleaf pine forests of the southern coastal plains. The midwestern prairies have been all but destroyed through conversion to agriculture—the original extent of these prairies is shown in Figure 4.2. As ecosystems shrink, the species that live in them become imperiled as well. The longleaf pine ecosystem of the southern coastal plain, for instance, is home to 27
TABLE 4.3 Critically endangered, endangered, and threatened ecosystems Decline refers to destruction, conversion to other land uses, or significant degradation of ecological structure, function, or composition since European settlement. Estimates are from quantitative studies and qualitative assessments.
Critically endangered (>98% decline) ecosystems
Coastal redwood (Sequoia semper virens) forests in California.
Old-growth and other virgin stands in the eastern deciduous forest biome.
Old-growth ponderosa pine (Pinus ponderosa) forests in the northern Rocky Mountains, Intermountain West, and eastside Cascades Mountains.
Spruce-fir (Picea rubens-Abies fraseri) forest in the southern Appalachians.
Riparian forests in California, Arizona, and New Mexico.
Red pine (Pinus resinosaa) and white pine (Pinus strobus) forests (mature and old-growth) in Michigan
Coastal sage scrub (especially maritime) and coastal mixed chaparral in southern California.
Longleaf pine (Pinus palustri s) forests and savannas in the southeastern coastal plain.
Dry forest on main islands of Hawaii.
Slash pine (Pinus elliottii) rockland habitat in South Florida.
All types of native habitats in the lower delta of the Rio Grande River, Texas.
Loblolly pine-shortleaf pine (Pinus taeda-Pinus echinata) hardwood forests in the West Gulf Coastal Plain.
Tallgrass prairie (all types combined).
Arundinaria giganteacanebrakes in the Southeast.
Native shrub and grassland steppe in Oregon and in Washington.
Tallgrass prairie east of the Missouri River and on mesic sites across range.
Low elevation grasslands in Montana.
Bluegrass savanna-woodland and prairies in Kentucky.
Gulf Coast pitcher plant (Sarraceniaspp.) bogs.
Black Belt prairies in Alabama and Mississippi and in the Jackson Prairie in Mississippi.
Pocosins (evergreen shrub bogs) and ultramafic soligenous wetlands in Virginia.
Ungrazed dry prairie in Florida.
Mountain bogs (southern Appalachian bogs and swamp forest-bog complex) in Tennessee and in North Carolina.
Oak (Quercus spp.) savanna in the Midwest.
Upland wetlands on the Highland Rim of Tennessee.
Wet and mesic coastal prairies in Louisiana.
Saline wetlands in eastern Nebraska.
Lakeplain wet prairie in Michigan.
Wetlands (all types combined) in south-central California, Illinois, Indiana, Iowa, Missouri, Nebraska, and Ohio.
Sedge (Carexspp. and others) meadows in Wisconsin.
Hempstead Plains grasslands on Long Island, New York.
Marshes in the Carson-Truckee area of western Nevada.
Lake sand beaches in Vermont.
Low-elevation wetlands in Idaho.
Serpentine barrens, maritime heathland, and pitch pine (Pinus rigida) -heath barrens in New York.
Woody hardwood draws, glacial pothole ponds, and peatlands in Montana.
Vernal pools in the Central Valley and in southern California.
Prairies (all types) and oak savannas in the Willamette Valley and in the foothills of the Coast Range, Oregon.
Marshes in the Coos Bay area of Oregon.
Palouse prairie (Idaho, Oregon, and Washington and in similar communities in Montana).
Freshwater marsh and coastal salt marsh in Southern California.
Native grasslands (all types) in California.
Seasonal wetlands of the San Francisco Bay, California.
Alkali sink scrub in southern California.
Large streams and rivers in all major regions.
Coastal strand in southern California.
Aquatic mussel (Unionidae) beds in Tennessee.
Ungrazed sagebrush steppe in the Intermourtain West.
Submersed aquatic vegetation in the Chesapeake Bay, in Maryland, and in Virginia.
Basin big sagebrush (Artenisia tridentata) in the Snake River Plain of Idaho.
Mangrove swamps and salt marsh along the Indian River lagoon, Florida.
Atlantic white-cedar (Chamaecyparis thyoides) stands in the Great Dismal Swamp of Virginia and in North Carolina and possibly across the entire range.
Seagrass meadows in Galveston Bay, Texas.
Threatened (70-84% decline)
Streams in the Mississippi Alluvial Plain.
Nationwide riparian forests (other than in already listed regions), including southern bottomland hardwood forests.
Endangered (85-98% decline)
Old-growth and other virgin forests in regions and in states other than in those already listed, except in Alaska.
Xeric habitats (scrub, scrubby flatwoods, sandhills) on the Lake Wales Ridge, Florida.
Tropical hardwood hammocks on the central Florida keys.
Mesic limestone forest and barrier island beaches in Maryland.
Northern hardwood forest, aspen (Populusspp.) parkland, and jack pine (Pinus banksiana) forests in Minnesota.
Coastal plain Atlantic white-cedar swamp, maritime oak-holly (Quercusspp.-Ilexspp.) forest, maritime redcedar (Juniperus virginiana) forest, marl fen, marl pond shore, and oak openings in New York.
Saline prairie, western upland longleaf pine forest, live oak-pine-magnolia (Quercus virginiana-Pinusspp.-Magnoliaspp.) forest, western xeric sandhill woodland, slash pine pond baldcypress-hardwood (Pinus elliottii-Taxodium ascendens) forest, wet and mesic spruce-pine (P. glabra) -hardwood flatwoods, wet mixed hardwood-loblolly pine (Pinus taeda) flatwoods, and flatwoods ponds in Louisiana.
Coastal heathland in southern New England and on Long Island.
Pine-oak-heath sandplain woods and lake sand beach in Vermont.
Floodplain forests in New Hampshire.
Alvar grassland, calcareous pavement barrens, dwarf pine ridges, mountain spruce-fir forest, inland Atlantic whitecedar swamp, freshwater tidal swamp, inland salt marsh, patterned peatland, perched bog, pitch pine-blueberry (Pinus rigida-Vaccinium spp.) peat swamp, coastal plain poor fens, rich graminoid fen, rich sloping fen, and riverside ice meadow in New York.
Red spruce (Picea rubens) forests in the central Appalachians (West Virginia).
Upland hardwoods in the Coastal Plain of Tennessee.
Lowland forest in southeastern Missouri.
High-quality oak-hickory (Quercusspp.-Caryaspp.) forest on the Cumberland Plateau and on the Highland Rim of Tennessee.
Maritime-like forests in the Clearwater Basin of Idaho.
Woodland and chaparral on Santa Catalina Inland.
Limestone redcedar (Juniperus virginianus) glades in Tennessee.
Southern tamarack (Lark laricina) swamp in Michigan.
Wet longleaf pine savanna and eastern upland longleaf pine forest in Louisiana.
Wetlands (all kinds) in Arkansas, Connecticut, Kentucky, and Maryland.
Calcareous prairie, Fleming glade, shortleaf pine/oak-hickory forest, mixed hardwood-loblolly pine forest, eastern xeric sandhill woodland, and stream terrace sandy woodland/savanna in Louisiana.
Marshes in the Puget Sound region, Washington.
Cienegas (marshes) in Arizona.
Slash pine (Pinus elliottii) forests in southwestern Florida.
Coastal wetlands in California.
Red pine and white pine forest in Minnesota.
SOURCE: Reed F. Noss, Edward T. LaRoe III, and J. Michael Scott, "Appendix B," in Endangered Ecosystems of the United States: A Preliminary Assessment of Loss and Degradations, U.S. Geological Survey, Reston, VA, 1995 [Online] http://biology.usgs.gov/pubs/ecosys.htm [accessed February 12, 2004]
TABLE 4.4 Human-caused reductions in westside California plant communities and formations
Vegetation reduced (percent)
Southern San Joaquin Valley alkali sink scrub
Southern California coastal sage-scrub
Coast redwood forest
SOURCE: M. J. Mac, P. A. Opler, C. E. Puckett Haecker, and P. D. Doran, "Table 1. Human-Caused Reductions in Westside California Plant Communities and Formations (after Noss and Peters, 1995)," in The Status and Trends of Our Nation's Biological Resources, U.S. Geological Survey, Reston, VA, 1998
species on the Endangered Species List and another 99 species that have been proposed for listing.
The full NBS list of the most endangered ecosystems of the United States appears in Table 4.3. Thirty-two American ecosystems had declined by more than 98 percent and were classified as "critically endangered." Fifty-eight had declined by 85 to 98 percent and were classified as "endangered." Thirty-eight others declined by 70 to 84 percent and were listed as "threatened."
Endangered ecosystems were found in all major regions of the United States except Alaska. The greatest losses occurred in the Northeast, the South, and the Midwest, as well as in California. A list of some Californian plant communities, most of which are unique to the state, and percentage reductions in these community types appear in Table 4.4. Native grasslands, needlegrass steppes, and alkali sink scrubs are among the communities that have declined most precipitously in California.
Endangered ecosystems are linked to many federally listed threatened and endangered species. Table 4.5 shows the endangered, threatened, proposed, and candidate species that are found in old-growth forests in the Pacific Northwest. Although the northern spotted owl has become linked to this region in the minds of many, these forest habitats are essential to numerous other endangered species. Table 4.6 provides a similar list for the endangered coastal sage scrub ecosystem in California. Table 4.7 lists species associated with the critically endangered longleaf pine and wiregrass communities of the southern coastal plain (which includes parts of North and South Carolina, Georgia, Florida, Alabama, Mississippi, and Louisiana).
Because of its isolation from continental land masses, many of the species found in Hawaii exist nowhere else in
TABLE 4.5 At-risk species living in late-successional forests in western Oregon, Washington, and northwestern California
Oregon chub (Oregonichthys crameri) E
Marbled murrelet (Brachyramphus marmoratus) T
Bald eagle (Haliaeetus leucocephalus) E
Northern spotted owl (Strix occidentalis caurina) T
Candidate and proposed species
Wayside aster (Aster vialis) 2
Bensonia (Bensoniella oregana) 2
Mt. Mazama collomia (Collomia mazama) 2
Cold-water corydalis (Corydalis aquae-gelidae) 2
California floater mussel (Anodonta californiensis)
Columbia pebblesnail or great Columbia river spire snail (Fluminicola [= Lithoglyphu columbiana) 2
Snail (Monadenia fidelis minor) 2
Trinity bristlesnail or California northern river snail (Monadenia setosa) 2
Columbia pebblesnail or spire snail (Monadenia troglodytes troglodytes)
Pacific western big-eared bat (Plecotus townsendii townsendii) 2
E = Listed Endangered
T = Listed Threatened
2 = Candidate Category 2 (taxa that existing information indicates may warrant listing but for which substantial biological data in support of a proposed rule are lacking).
SOURCE: Reed F. Noss, Edward T. LaRoe III, and J. Michael Scott, "Appendix C," in Endangered Ecosystems of the United States: A Preliminary Assessment of Loss and Degradations, U.S. Geological Survey, Reston, VA, 1995 [Online] http://biology.usgs.gov/pubs/ecosys.htm [accessed February 12, 2004]
the world. An estimated 90 percent of Hawaiian plant species are in fact endemic. Because of large-scale deforestation and habitat destruction on the Hawaiian islands, Hawaii is home to more endangered plants than any other state in the nation, with 312 listed species in 2004. Hawaiian plants have suffered from the introduction of invasive predators such as cows, pigs, and insects, as well as the loss of critical pollinators with the decline of numerous species of native birds and insects. Over 10 percent of Hawaiian plant species have gone extinct in the last few hundred years, and nearly 30 percent are currently believed to be imperiled.
In April 2002, a major step in protecting Hawaii's endemic flora was taken when the Fish and Wildlife Service
TABLE 4.6 At-risk species living in coastal sage scrub habitats in southern California
Otay tarplant (Hemizonia conjugens) 2
California gnatcatcher (Polioptila californica californica) T
Santa Susana Mountains tarplant (Hemizonia minthornii) 2
Nevin's barberry (Mahonia nevinii) 1
Davidson's bush mallow (Malacothamnus davidsonii) 2
1 = Candidate Category 1 (taxa for which the U.S. Fish and Wildlife Service has sufficient biological information in support of a listing proposal.
2 = Candidate category 2 (taxa for which existing information indicates listing but for which substantial biological data in support of a proposed rule are lacking).
SOURCE: Reed F. Noss, Edward T. LaRoe III, and J. Michael Scott, "Appendix D," in Endangered Ecosystems of the United States: A Preliminary Assessment of Loss and Degradations, U.S. Geological Survey, Reston, VA 1995 [Online] http://biology.usgs.gov/pubs/ecosys.htm [accessed February 12, 2004]
proposed critical habitat for native plant species on the islands of Maui and Kahoolawe. The proposal includes fifteen habitat areas covering approximately 128,000 acres. Protection of these areas would benefit at least 61 threatened and endangered species by preserving current habitat, as well as allowing for natural range expansion and the reintroduction of endangered species into portions of their historic ranges. The areas proposed for critical habitat include Hawaii state lands (45 percent), federal lands (17 percent), and privately owned land (37 percent). Only activity on federal lands is legally affected by critical habitat designation.
In July 2003 the Fish and Wildlife Service designated over 208,000 acres of critical habitat on the island of Hawaii (Big Island) as habitat for forty-one listed plant species. The area designated was 52 percent smaller than originally anticipated because it excluded a large tract of U.S. Army land as well as private land held by the Queen Liliuokalani Trust and others. The U.S. Army land was excluded because of national security concerns and because the Army agreed to voluntarily cooperate with the Fish and Wildlife Service regarding activity that affects endangered species. The Queen Liliuokalani Trust land was excluded because the trust vowed to discontinue its current efforts on behalf of endangered species if its lands were included in the critical habitat designation. Finally, land near the cities of Kailua and Kona, for which housing development was planned, was excluded from critical habitat designation because the economic and social costs of inclusion were too great.
Designation of critical habitat in Hawaii was completed after a successful lawsuit brought against the Fish and Wildlife Service by Earthjustice, the Conservation Council for Hawaii, the Sierra Club, and the Hawaii Botanical Society.
Profiles of Some Endangered North American Plants
Over thirty cactus species are currently listed with the U.S. Fish and Wildlife Service as either threatened or endangered. Most of these species are found in arid habitats in the Southwest, particularly Texas,
TABLE 4.7 At-risk species living in longleaf pine or wiregrass habitats in the southern coastal plain
Apalachicola rosemary (Conradina glabra ) E
Pigeon-wing (Clitoria fragrans) T
Beautiful pawpaw (Deeringothamnus pulchellus) E
Rugel's pawpaw (Deeringothamnus rugellii) E
Scrub mint (Dicerandra frutescens) E
Scrub buckwheat (Eriogonum longifolium var. gnaphalifolium) T
Harper's beauty (Harperocallis flava) E
Rough-leaf loosestrife (Lysimachia asperulifolia) E
Britton's bear grass (Nolina brittonia) E
Godfrey's butterwort (Pinguicula ionantha) T
Chapman's rhododendron (Rhododendron chapmanii) E
Michaux's sumac (Rhus michauxii) E
Green pitcherplant (Sarracenia oreophila) E
Chaffseed (Schwalbea americana ) E
Gentian pinkroot (Spigelia gentianoides) E
Cooley's meadowrue (Thalictrum cooleyi ) E
Clasping warea (Warea amplexifolia) E
Carter's warea (Warea carteri) E
Gopher tortoise (Gopherus polyphemus) T
Sand skink (Neoceps reynoldsi) T
Indigo snake (Drymarchon corais couperi) T
Blue-tailed mole skink (Eumeces egregius lividus) T
Mississippi sandhill crane (Grus canadensis pulla) E
Bald eagle (Haliaeetus leucocephalus) E
Florida scrub jay (Aphelocoma coerulescens coerulescens) T
Red-cockaded woodpecker (Picoides borealis) E
Florida panther (Felis concolor coryi) E
Candidate and proposed species
Incised groovebur (Agrimonia incisa) 2
Carolina lead plant (Amorpha georgiana var. confusa) 2
Georgia lead plant (Amorpha georgiana var. georgiana) 2
Black pine snake (Pituophis melanoleucus lodingi) 2
Northern pine snake (Pituophis melanoleucus melanoleucus) 2
Florida pine snake (Pituophis melanoleucus mugitus) 2
Short-tailed snake (Stilosoma extenuatum) 2
Southeastern American kestrel (Falco sparverius paulus) 2
Loggerhead shrike (Lanius ludovicianus) 2
Bachman's sparrow (Aimophila aestivalis) 2
Henslow's sparrow (Ammodramus henslowii) 2
The star cactus is a spineless species found in Texas and parts of Mexico, and was listed as endangered across its entire range in 1993. In Texas, it is found only along a
TABLE 4.7 At-risk species living in longleaf pine or wiregrass habitats in the southern coastal plain
Florida weasel (Mustela frenata peninsulae) 2
Florida black bear (Ursus americanus floridanus) 2
Florida mouse (Podomys floridanus) 2
Sherman's fox squirrel (Sciurus niger shermani) 2
E = endangered
PT = proposd threatened
T = threatened
1 = candidate category 1 (taxa for which the U.S. Fish and Wildlife Service has sufficient biological information in support of a listing proposal).
2 = candicate category 2 (taxa for which existing information indicates listing but for which substantial biological data in support of a proposed rule are lacking).
SOURCE: Reed F. Noss, Edward T. LaRoe III, and J. Michael Scott, "Appendix E," in Endangered Ecosystems of the United States: A Preliminary Assessment of Loss and Degradations, U.S. Geological Survey, Reston, VA, 1995 [Online] http://biology.usgs.gov/pubs/ecosys.htm [accessed February 12, 2004]
single creek system in Starr County. The star cactus is several inches in diameter and only a few inches tall. The flowers have large yellow petals that form a deep bowl. Endangerment of this species resulted partly from over-collection in the wild by cactus enthusiasts, who greatly prize it. The star cactus has also suffered from habitat loss due to urban and agricultural development. The San Antonio Botanical Garden has attempted to aid conservation efforts by developing methods for propagating this species from seed.
The bunched cory cactus was first listed as threatened in 1979. It is a small species, reaching heights of up to four inches. The bunched cory cactus has rounded, single stems and occupies ledges and flats on limestone outcrops. Populations occur in Big Bend National Park in Texas, as well as on some private ranches—a total of approximately 25 different sites are known. Despite strict regulations against collection and monitoring in park sites, cactus poachers nonetheless continue to collect the plant illegally.
Showy stickseed is one of the most recent plants to be added to the Endangered Species List. It was officially listed in February 2002 as endangered throughout its habitat—a single site in the Wenatchee National Forest in Chelan County in the state of Washington. Showy stickseed was once observed at a second site in Chelan County but is now believed to be extinct there. Approximately 1,000 showy stickseed plants existed in the early 1980s, but only 500 plants were found in a 2001 survey. Critical habitat was not designated for showy stickseed by the Fish and Wildlife Service because it was believed to be imprudent to reveal the location of the sole population for fear of illegal collection.
Showy stickseed is an herb eight to sixteen inches tall. When in bloom, it has large, white flowers. Endangerment is believed to have resulted from competition with invasive species such as weeds, woody shrubs, and trees. Showy stickseed requires large amounts of sunlight, which has become increasingly blocked by the larger invasive species. A long history of fire suppression has also contributed to the shading problem. The other major factor contributing to endangerment of this species is collection from the wild. Now that the species is listed under the Endangered Species Act, collection is considered a federal crime. The Fish and Wildlife Service is cooperating with the Wenatchee National Forest and the Washington Department of Transportation to help improve habitat areas for the showy stickseed. This includes thinning of invasive tree species and control of weeds. In addition, experimental propagation of the stickseed is being pursued.
In March 2002, the desert yellowhead was listed as threatened in its only known habitat, 50 acres of federal land in Wyoming. There were about 12,000 plants found in a survey conducted in 2001. The desert yellowhead is related to sunflowers, and has twenty-five to eighty flowers crowded atop each twelve-inch stem. The species was first discovered in 1990. The desert yellowhead is threatened due to human activity. Portions of its current habitat are being considered for oil and gas drilling. The Fish and Wildlife Service is working with the Bureau of Land Management, which manages desert yellowhead habitat, on a conservation plan.
The Robbins' cinquefoil was officially listed as endangered in 1980. This plant species is related to roses, and is found in the alpine zone of the White Mountain National Forest in New Hampshire. It is a small species that bears a yellow flower. At the time of listing, there were approximately 3,700 plants surveyed. After concerted conservation efforts involving the Fish and Wildlife Service, the U.S. Forest Service, and the Appalachian Mountain Club, the population of the Robbins' cinquefoil increased to over 14,000 plants in 2001. In June 2001, the species was proposed for delisting. Critical actions that helped the population recover included a rerouting of the Appalachian Trail around the critical habitat areas of the species, as well as the building of an enclosure to protect the population from disturbance. In addition, two populations of Robbins' cinquefoil were introduced in new National Forest habitats.
LOS ANGELES BASIN MOUNTAIN PLANTS.
Numerous species of threatened and endangered plants have reached their precarious state due to urbanization and other human activity. Figure 4.3 shows the species distribution of six threatened and endangered plant species found in the mountains surrounding the Los Angeles basin. The recovery plan for these species lists current threats to species survival as including: "urban development, recreational activities, alteration of fire cycles, fire suppression and pre-suppression (fuel modification) activities, over-collecting,
FIGURE 4.3 Distribution of six endangered plant species in the mountains surrounding the Los Angeles Basin
habitat fragmentation and degradation, and competition from invasive weeds." Some species are currently so reduced in number that extinction due to random events is also a threat.
Mead's milkweed is a federally listed threatened species with populations in Kansas, Missouri, Iowa, and Illinois. The species has already gone extinct in Wisconsin and Indiana. Most population loss is attributed to agriculture. Figure 4.4 shows the counties where Mead's milkweed currently persists, counties where it once existed but is now extinct, and counties where reintroductions into suitable habitat are taking place. Table 4.8 lists the summary of threats to Mead's milkweed as well as the recommended recovery actions that appeared in the species recovery plan, published in September 2003 by the Fish and Wildlife Service.
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