Hawaiian Plants
Figure 11.4 shows the eight major islands comprising the state of Hawaii. The island of Oahu is home to the state's capital, Honolulu. However, Oahu is not the largest of the islands. That distinction goes to the island labeled "Hawaii," which is commonly called "the big island." In the following discussion, the term Hawaii refers to the entire state.
FIGURE 11.4 The main Hawaiian Islands
Because of its isolation from continental land masses, many of the species found in Hawaii exist nowhere else in the world. An estimated 90% of Hawaiian plant species are in fact endemic. Because of large-scale deforestation and habitat destruction on the islands, Hawaii is home to more threatened and endangered plants than any other state in the nation. The U.S. Fish and Wildlife Service (2006, http://www.fws.gov/pacificislands/wesa/endspindex.html) reports that in 2006 there are 273 listed species in Hawaii. 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. According to Marie M. Bruegemann in "A Plan for Hawaiian Plants and Their Ecosytems" (Endangered Species Bulletin, July-December 2003), 100 of Hawaii's 1,500 known plant species are believed to have become extinct since the islands were colonized by humans.
The U.S. Fish and Wildlife Service has developed more than a dozen recovery plans for imperiled Hawaiian plants. Many of the plans cover multiple species found in the same ecosystem or habitat types. Examples include:
- Oahu plants—sixty-six species
- Kauai plant cluster—thirty-seven species
- Waianae plant cluster—thirty-one species
- Multi-island plants—twenty-six species
- Big Island plant cluster—twenty-two species
In 2003 the FWS designated over 208,000 acres of critical habitat on the Big Island as habitat for forty-one listed plant species. The area designated was 52% 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 also because the Army agreed to voluntarily cooperate with the FWS 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.
Californian Plants
As shown in Figure 11.3 California is home to 22% of threatened and endangered plant species in the United States. More than 160 imperiled plants are found there, including several types of checker-mallow, dudleya, evening primrose, grass, jewelflower, larkspur, manzanita, milk-vetch, paintbrush, rock-cress, spineflower, and thistle.
MILK-VETCH
Milk-vetch is an herbaceous perennial flowering plant found in various parts of the world. It received its common name during the 1500s thanks to a belief among European farmers that the plant increased the milk yield of goats. As of March 2006 there were ten species of milk-vetch listed as threatened or endangered in California, the most listings for any single plant type in that state. These species are as follows:
- Braunton's milk-vetch (Astragalus brauntonii)
- Clara Hunt's milk-vetch (Astragalus clarianus)
- Coachella Valley milk-vetch (Astragalus lentiginosus var. coachellae)
- Coastal dunes milk-vetch (Astragalus tener var. titi)
- Cushenbury milk-vetch (Astragalus albens)
- Fish Slough milk-vetch (Astragalus lentiginosus var. piscinensis)
- Lane Mountain milk-vetch (Astragalus jaegerianus)
- Peirson's milk-vetch (Astragalus magdalenae var. peirsonii)
- Triple-ribbed milk-vetch (Astragalus tricarinatus)
- Ventura Marsh milk-vetch (Astragalus pycnostachyus var. lanosissimus)
FIGURE 11.5 Location of the Imperial Sand Dunes Recreation Area
Peirson's milk-vetch is a plant with a long history of litigation and controversy in California. It is found in only one small area of Imperial County in the southern part of the state. (See Figure 11.5.) This area is the Imperial Sand Dunes Recreation Area (ISDRA) managed by the Bureau of Land Management under the U.S. Department of the Interior. ISDRA has a remote and barren landscape dominated by huge rolling sand dunes—the Algodones Dunes, the largest sand dune fields in North America. ISDRA covers 185,000 acres and is a popular destination for off-highway vehicle (OHV) riders, receiving more than one million visitors annually.
In 1998 Peirson's milk-vetch was designated a threatened species by the U.S. Fish and Wildlife Service because of the threat of destruction by OHVs and other recreational activities at Imperial Sand Dunes Recreation Area. The agency decided not to designate critical habitat at that time, fearing the remaining plants would be subject to deliberate vandalism. The Bureau of Land Management was sued by conservation groups and accused of not consulting with the FWS about the threats to the Peirson's milk-vetch before establishing a management plan for the Recreation Area. In 2000, in response to that lawsuit, the Bureau of Land Management closed more than a third of the ISDRA to off-highway vehicle use.
In October 2001 a petition to delist the species was submitted on behalf of the American Sand Association, San Diego Off-Road Coalition, and Off-Road Business Association. A month later two lawsuits were filed against the Fish and Wildlife Service by conservation organizations challenging the agency's decision not to designate critical habitat for the species. Under court order, the FWS proposed critical habitat in 2003. Meanwhile the delisting petition submitted in 2001 triggered a status review.
In 2004 the FWS issued a final designation of critical habitat for Peirson's milk-vetch that encompassed nearly 22,000 acres of Imperial Sand Dunes Recreation Area. This was less than half of the acreage originally proposed. The reduction was made after an economic analysis revealed that closure of ISDRA areas to off-road vehicle use would have a negative impact on local businesses. That same year the agency completed the status review triggered by the 2001 delisting proposal and found that the species should remain listed as threatened. In July 2005 the original petitioners and additional OHV and motorcycle associations submitted a new petition to delist Peirson's milk-vetch. This petition also triggered a status review, which was expected to be completed in late 2006. In a public statement, the U.S. Fish and Wildlife Service noted that the new petition contains data indicating that the species is more abundant and widespread than originally believed.
As of spring 2006 portions of the ISDRA remained under temporary closure to off-highway vehicle riders due to ongoing litigation against the Bureau of Land Management regarding management of the Recreation Area.
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 11.6 shows the species distribution of six threatened and endangered plant species found in the mountains surrounding the Los Angeles basin:
- Braunton's milk-vetch (Astragalus brauntonii)
- Marcescent dudleya (Dudleya cymosa ssp. marces-cens)
- Santa Monica Mountains dudleya (Dudleya cymosa ssp. ovatifolia)
- Conejo dudleya (Dudleya abramsii ssp. parva)
- Verity's dudleya (Dudleya verityi)
- Lyon's pentachaeta (Pentachaeata lyonii)
The recovery plan for these species cites threats including "urban development, recreational activities, alteration of fire cycles through fire suppression and pre-suppression (fuel modification) activities, over-collecting, 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.
Floridian Plants
As shown in Figure 11.3, the southeastern states contain 14% of the threatened and endangered plant species listed under the ESA as of March 2006. Approximately half of these listed plants are found only in Florida. They include multiple species of mint, pawpaw, rosemary, and spurge.
Many of Florida's imperiled plants are found in the southern part of the state—the only subtropical ecological habitat in the continental United States. Figure 3.2 in Chapter 3 shows a map of the south Florida ecosystem, including its national parks, national preserves, and numerous national wildlife refuges. The Fish and Wildlife Service maintains a field office in this area in Vero Beach, Florida. The majority of native plant species located in the bottom half of the south Florida ecosystem originated from the tropics.
In 1999 the FWS published the South Florida Multi-Species Recovery Plan (MSRP) covering sixty-six species, including dozens of plant species. In 2004 an implementation schedule for many of the species in the plan was issued, which divided the ecosystem into ecological communities as follows:
- Florida scrub/scrubby flatwoods/scrubby high pine—nineteen plant species
- Pine rocklands—five plant species
- Beach dune/coastal strand—one plant species
- Tropical hardwood hammock—one plant species
- Mesic and hydric pine flatwoods—one plant species
- Freshwater marsh/wet prairie—one plant species
The recovery and restoration tasks outlined in the MSRP are to be implemented through creation of a team of federal, state, and local governmental agencies; Native American tribal governments; academic representatives; industry representatives; and members of the private sector. The schedule prioritizes the plan's recovery actions
FIGURE 11.6 Distribution of six endangered and threatened plant species in the mountains surrounding the Los Angeles basin
The South Florida Multi-Species Recovery Plan is considered a landmark plan, because it was one of the first recovery plans to focus on an ecosystem approach to recovery, rather than a species-by-species approach.
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