Overview
Sacramento Mountains thistle (Cirsium vinaceum, Wooton & Standley 1913) is a short-lived, monocarpic perennial plant endemic to elevations between 2460 and 3020 meters (7,500 and 9,200 feet) in the Sacramento Mountains of Otero County, New Mexico. The geographic range of this species spans approximately 32 kilometers (km) (20 miles (mi)), with individual C. vinaceum found in association with 6 major canyon drainages. Sacramento Mountains thistle is a wetland-obligate species confined to wet travertine deposits on springs and seeps, and water-saturated alkaline soils in open valley bottoms. Suitable thistle habitats are relatively rare, spotty in distribution, and range in size from several square meters (m2) to over 1000 m2. These small habitats are often densely occupied, forming patches of C. vinaceum ranging from fewer than 10 flowering individuals up to several thousand and providing conditions for a set of metapopulations. The total area of habitat occupied by this species is estimated to be approximately 28 hectares (ha) (70 acres (ac)), with greater than 95 percent of known habitats occurring on the Lincoln National Forest (U.S. Fish and Wildlife Service 2010).
The Sacramento Mountains thistle was listed as a threatened species under the ESA, as amended, on June 16, 1987 (U.S. Fish and Wildlife Service 1987). Endemic to the Sacramento Mountains of south-central New Mexico, it was originally discovered in 1899 by E.O. Wooton near Fresnal, New Mexico. The type specimen for Cirsium vinaceum is in the U.S. National Herbarium, No. 690246, from "the Sacramento Mountains near Fresnal" (Wooton and Standley 1913). The population at this type locality has since been extirpated by agricultural activities. The remaining populations are mostly limited to locations on the Lincoln National Forest in mixed conifer/mountain meadow associations, though there may be populations on city, state, private, and Tribal lands. The thistle was listed under the ESA due to threats from water diversion at spring habitats, direct and indirect impacts from grazing, competition with exotic plants, logging, and recreation. Livestock grazing is the prevailing land use throughout the range of the Sacramento Mountains thistle, and consumption and trampling of the thistle as well as hoof damage to travertine substrates continue in areas occupied by the thistle with unmaintained or inadequate fencing. Exotic weed species persist within Sacramento Mountains thistle habitats, and roadside spraying for weed control occasionally causes mortality to adjacent Sacramento Mountains thistle individuals (U.S. Fish and Wildlife Service 2010).
Scientific Name
Identification Numbers
Characteristics
Habitat
Sacramento Mountains thistle is a wetland species confined to wet travertine deposits at alkaline springs and seeps and permanently wet alkaline soils in valley bottoms. Many of the wet travertine deposits form on very steep slopes and are covered with dense patches of the thistle to the point of being nearly a monoculture of this species (Thomson 1991). Thistle patches range from fewer than 10 flowering individuals in a season to several thousand (Burks 1994).
Thistle habitats occur in mixed conifer forests and open valleys. The predominant land uses are wildlife habitat, livestock grazing, recreation, timber production, and home construction. Some land uses have directly and indirectly modified the local ecosystem from it natural condition. Disturbance and use have especially contributed to the significant variety and abundance of exotic weed species in the Sacramento Mountains. Exotic plant species associated with Sacramento Mountains thistle habitats include teasel (Dipsacus fullonum), musk thistle (Carduus nutans), poison hemlock (Conium maculatum), Canada thistle (Cirsium arvense), bull thistle (Cirsium vulgare), Queen Anne's lace (Daucus carota), dandelion (Taraxicum officinale), watercress (Nasturtium officinale), salsify (Tragopogon pratensis) and mullein (Verbascum thapsus) (Thomson 1991, Huenneke 1996, U.S. Forest Service 2000). These invasive plants have the capacity to compete with the Sacramento Mountains thistle for light (Huenneke and Thomson 1995), and possibly for water under drier conditions.
A dense growth of trees and underbrush covering a large tract.
A landmass that projects conspicuously above its surroundings and is higher than a hill.
A natural body of running water.
Of or relating to cities and the people who live in them.
Environments influenced by humans in a less substantial way than cities. This can include agriculture, silvaculture, aquaculture, etc.
Areas such as marshes or swamps that are covered often intermittently with shallow water or have soil saturated with moisture.
Areas where ground water meets the surface.
Physical Characteristics
The Sacramento Mountains thistle is a stout biennial, 1-1.8 meters (3.3-5.9 feet) tall, with many ascending, brown-purple branches. The basal leaves are green, not hairy, 30-50 centimeters (12-20 inches) long, up to 20 centimeter& (8 inches) wide, ragged edged, and divided nearly to the midrib, the divisions tipped with slender yellow spines. Flowering heads are 5 centimeters (2 inches) in diameter and almost as high, numerous at the ends of branches, naked, and bell-shaped; involucral bracts are of several ranks, deep red-purple, bent back at about the middle, and tipped with short yellowish spines. Flowers are pink-purple; the fruits or achenes are obovate, brown, and glabrous, with a tawny plumose pappus 15-20 millimeters (0,6-0.8 inches) long.
Life Cycle
Sacramento Mountains thistle is a monocarpic, short-lived perennial initially forming robust rosettes of spiny leaves that live for one or more years as juvenile plants (Burks 1994). Each rosette eventually bolts a flowering stem, spends a single growing season as a reproductive adult, and dies upon seed set. Individuals may produce multiple rosettes along rhizomes or rooting rosette leaves and be able to produce more than one flowering stem during the same, or a different, year (Huenneke 1996).
Sacramento Mountains thistle is a monocarpic, short-lived perennial initially forming robust rosettes of spiny leaves that live for one or more years as juvenile plants (Burks 1994).
Seed production usually occurs from cross-pollination, although this species is partially self-compatible. Pollen is carried by a variety of animal vectors including several species of native bees, flies, butterflies, and hummingbirds (Griswold 1990, Tepedino 2002). Burks (1994) studied pollen movement between thistles and found that native bee activity was lower, and heterospecific pollen loads on stigmas was higher, in small patches of trusties (<100 flowering individuals) than in large thistle patches (>1,000 flowering individuals). Burks also found that small patches of thistles were apparently not pollinator limited since there was no significant difference in seed set between small and large thistle patches. Therefore, small patches of Sacramento Mountains thistle are able to experience reproductive success and must be considered "viable" or capable of persisting over time (Huenneke 1996).
Similar Species
The sympatric native thistle species, Parry's thistle (Cirsium parryi) and Wright's marsh thistle (Cirsium wrightii), are known to be capable of crossbreeding with Cirsium vinaceum and produce hybrid offspring (Barlow-Irick 2002). C. wrightii is an endemic, wetland thistle and is sympatric with C. vinaceum at only one known location on the Lincoln National Forest where hybrid offspring are uncommon. C. parryi is relatively common throughout much of the mountain range and will occasionally hybridize with C. vinaceum (Barlow-Irick 2007).
Geography
Sacramento Mountains thistle is a short-lived, monocarpic perennial plant endemic to elevations between 2460 and 3020 meters (7,500 and 9,200 feet) in the Sacramento Mountains of Otero County, New Mexico. The geographic range of this species spans approximately 32 kilometers (km) (20 miles (mi)), with individual C. vinaceum found in association with 6 major canyon drainages. The total area of habitat occupied by this species is estimated to be approximately 28 hectares (ha) (70 acres (ac)), with greater than 95 percent of known habitats occurring on the Lincoln National Forest.
From the original 20 occupied population sites for the thistle, the U.S. Forest Service has identified a total of 104 extant, historic, or potential habitat locations for C. vinaceum. All of these sites are distributed within the historically known geographic range at the time of listing in 1987 (U.S. Fish and Wildlife Service 2010). Currently, 83 localities (or subpopulations) are monitored as C. vinaceum sites. The extent of occupied sites and plant population numbers for a given year fluctuates with precipitation conditions and both surface and subsurface water flow. Of the known, occupied sites, five small thistle patches disappeared from their habitat locations by 2003, and an additional five patches disappeared by 2005. By 2007, an additional patch disappeared and another patch was occupied by rosettes but had no reproducing individuals with flowering stems. Total numbers of flowering stems have steadily declined from a peak in 1998 of 39,849 individuals to 24,124 in 2007. Drought patterns in the Sacramento Mountains began in 1999 and coincide with the declining trend of flowering thistle numbers observed on the Lincoln National Forest.
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