BLM Farmington Proposed RMP/final EIS
Public lands in San Juan, McKinley, Rio Arriba, and Sandoval Counties support a diversity of upland and riparian plant communities. These plant communities or vegetation types are controlled in large part by site-specific topography, soil type, and climatic conditions. The planning area contains five major vegetation units, as well as the non-native cover type represented by urban/agricultural areas, shown in Map 3-6 (Dick-Peddie 1993). An estimated 223,600 acres of desert grasslands are found within FFO boundaries, 65,500 acres are on AFO land, and 11,800 acres on USFS land (Table 3-8). There are large tracts of desert grassland vegetation throughout the central portion of the planning area. Blue grama (Bouteloua gracilis), galleta (Hilaria jamesii), and dropseeds (Sporobolus sp.) are common. Broom snakeweed (Gutierrezia sarothrae) occurs in most areas along with scattered big sagebrush (Artemisia tridentata) and one-seed juniper (Juniperus monosperma) on ridges and rocky areas (BLM 1988).
The Great Basin Desert Scrub plant community covers approximately 435,000 acres within FFO boundaries, 75,000 acres within AFO boundaries, and 200 acres on USFS land and dominates the landscape in the northwestern portion of the planning area. The major shrub species in this type are big sagebrush, shadscale (Atriplex confertifolia), greasewood (Sarcobatus vermiculatus), and fourwing saltbush (Atriplex canescens). Big sagebrush has increased dramatically over the past 125 years. Most areas now dominated by big sagebrush in New Mexico were grassland or savannah in the middle of the last century (Dick-Peddie 1993). Within Great Basin Desert Scrub, big sagebrush usually occurs at higher elevations than the saltbush communities. Other sagebrush species found with big sagebrush are black sage (Artemisia arbuscula) and Bigelow sage (A. bigelovii). Other shrub species found with saltbush include winterfat (Ceratoides lanata), rabbitbrush (Chrysothamnus sp.), and Nuttal’s saltbush (Atriplex nuttallii). Widespread grasses in this vegetation type include alkali sacaton (Sporobolus airoides), western wheatgrass (Agropyron smithii), Indian ricegrass (Oryzopsis hymenoides), and blue grama (Dick-Peddie 1993).
The Juniper Savannah plant community lies primarily in a band along the southern boundary of the planning area, and covers approximately 56,000 acres within FFO boundaries and 136,000 acres within AFO boundaries. This vegetation type occurs between the conifer woodlands and grasslands and has been expanding during this century due mainly to human activities, such as livestock grazing and fire suppression. This type consists of widely scattered low trees interspersed in grasslands. One-seed juniper and Utah juniper (Juniperus osteosperma) are typical, as are big sagebrush, Bigelow sagebrush, and shadscale. Blue grama, galleta, Indian ricegrass, and sideoats grama (Bouteloua curtipendula) are common grass species (Dick-Peddie 1993).
The Piñon-Juniper Woodland plant community type occurs primarily in the northeastern portion of the planning area and along the southern boundary. It covers an estimated 633,000 acres within FFO boundaries, 91,000 acres within AFO boundaries, 192,000 acres on USFS land, and 13,000 acres on USBR land. Trees in these woodlands can form a dense canopy or be fairly open. Dense stands generally occur above 6,600 feet in elevation and the dominant tree species are piñon (Pinus edulis), Utah juniper, Gambel’s oak (Quercus gambellii), and true mountain mahogany (Cercocarpus montanus), with occasional stringers of ponderosa pine (Pinus ponderosa). Common ground cover species are mutton grass (Poa fendleriana), western wheatgrass (Agropyron smithii), buckwheat (Eriogonum sp.), and penstemon (Penstemon sp.) (BLM 1997). More open stands are located on drier sites below 6,600 feet elevation where piñon, Utah juniper, big sagebrush and antelope bitterbush (Purshia tridentata) are common. Blue grama and galleta are the principal grass species. Relatively large stands of big sagebrush can occur within the open woodlands (BLM 1997).
The Ponderosa Pine Forest occurs principally on USFS land along the eastern boundary of the planning area, although there is a small amount on FFO land. There are an estimated 2,300 acres within FFO boundaries, 5,600 acres within AFO boundaries, and 43,300 acres on USFS land. This forest occurs on BLM land primarily in deep canyons on north and east facing slopes. Common tree species are ponderosa pine, piñon, and Douglas fir (Pseudotsuga menziesii). The shrub component is dominated by antelope bitterbush, true mountain mahogany, and Gambel’s oak with grass cover dominated by mutton grass and western wheatgrass. On the Jicarilla Ranger District and the Cuba Ranger District, this vegetation type occurs in scattered locations in deep canyons on north and east facing slopes. Dominant plant species at these locations are similar to those found on BLM lands.
The subalpine montane grasslands is represented by approximately 300 acres within FFO boundaries located on the very western side of the planning area along the New Mexico Arizona border. These grasslands are commonly found above 8,900 feet and up to 11,500 feet on relatively smooth terrain of southwestern exposures with slopes ranging from 20 to 50 percent (Dick-Peddie 1993). Dominant grasses in this vegetation unit include fescue (Festuca sp.), oatgrass (Danthonia sp.), tuft-hair grass (Deschampsia sp.), Junegrass (Koeleria sp.), bluegrass (Poa sp.), and muhly (Muhlenbergia sp.). Areas of heavy grazing experience vegetation community shifts from Thurber and Arizonia Fescue (Festuca thurberi
and F. arizonica respectively), oatgrass and Junegrass to Kentucky bluegrass (Poa pratensis) (Dick-Peddie 1993). Restoration to a pregrazing state of native vegetation occurs within 2 to 4 years if adequate recovery is allowed (Dick-Peddie 1993).
The subalpine coniferous forest unit occurs along the eastern boundary of the planning area with an estimated 6,700 acres of USFS land on the Santa Fe National Forest. The vegetation unit is characterized by elevations of approximately 9,500 feet to timberline, approximately 12,000 feet (Dick-Peddie 1993). Common flora include Englemann spruce (Picea englemanii), Douglas-fir, Juniper species, Corkbark fir (Abies lasiocarpa), currants (Ribes
sp.), fringed brome (Bromus ciliatus), mountain trisetum (Trisetum spicatum), and bluegrass (Dick-Peddie 1993). Vegetation communities vary among different alpine regions due to elevation and moisture differences.
The urban, farmland, and open water unit includes federal, state and private lands in the northern tier of the planning area. This vegetation unit represents the non-native land cover according to Dick-Peddie (1993). Open water areas are permanently inundated in surface water, such as the Navajo Reservoir. Irrigated cropland represents the farmland located adjacent to the San Juan, Animas, La Plata, and Los Piñas Rivers in this vegetation unit. Urban areas are concentrated in the tricities area (Aztec, Bloomfield, and Farmington).
Invasive plants are found in the San Juan Basin, particularly in areas disturbed by surface activities. These plants displace native plant communities and degrade wildlife habitat. A total of 212 invasive and poisonous weeds have been identified on FFO land (Heil and White 2000). Table 3-9 lists the invasive and non-native species of concern in the planning area and the current management classes for each species. The following management classes provide information on the current status of each species in the planning area and the priority for treatment:
• Class A: Non-native plants that have a limited distribution within or have not yet invaded the state. Some are found on public lands within the planning area, and preventing and eliminating infestations of these weeds has the highest priorities in the BLM management plan.
• Class B: Non-native plants that are presently limited to a particular part of the planning area. The management priorities are to contain them within their current areas and prevent new infestations.
• Class C: Non-native plants that are widespread throughout much of the public land within the planning area. Long-term programs of management and suppression are encouraged.
RIPARIAN AREAS AND WETLANDS
Riparian areas are defined by the BLM as “a form of wetland transition between permanently saturated wetlands and upland areas. These areas exhibit vegetation or physical characteristics reflective of permanent surface or subsurface water influence. Lands along, adjacent to, or contiguous with perennially and intermittent flowing rivers and streams, glacial potholes, and the shores of lakes and reservoirs with stable water levels are typical riparian areas” (Leonard et al. 1992). Wetlands are regulated by the U.S. Army Corps of Engineers (USACE) and defined as “those areas inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas” (US Army 1987).
Seventy riparian areas in 35 river tracts and along portions of nine ephemeral stream reaches were identified on FFO land as shown in Map 3-7(BLM 2000b). Subsequently, 13 additional tracts along ephemeral drainages were identified. Riparian areas associated with the river tracts comprise 471 acres along 20 miles of river adjacent to the Animas, San Juan, and La Plata Rivers and Pump Canyon Creek (Table 3-10) (BLM 2000b). An estimated 1,042 acres of riparian vegetation occurs along an estimated 109 miles of ephemeral streams including Blanco Reach, Carrizo Canyon, Ditch Canyon, Gobernador Canyon, Kutz Canyon, La Jara Canyon, Largo Canyon, Palluche Canyon, and Simon Canyon (BLM 2000b). Wetlands include the 25 acres Carrizo Oxbow wetland identified in BLM (2000b) and the more recently identified 10 acre Desert Hills wetland. Common plant species in riparian areas on FFO land are cottonwoods (Populusspp.), willows (Salix spp.), saltcedar (Tamarix spp.), Russian olive (Elaeagnus angustifolia), sedges (Carex spp.), rushes (Juncus spp.), reed canarygrass (Phalaris arundinacea), cattails (Typha spp.), bulrushes (Scirpus spp.), alkali sacaton, galletagrass, Indian rice-grass, sagebrush, greasewood, and four-wing saltbush (BLM 2000b).
Twenty riparian areas occur along 21 miles of the Rio Puerco, 18 miles of Arroyo Chico, and 3 miles of other ephemeral drainages, for a total of about 42 miles on AFO land (see Table 3-10). There are a total of 1,169 acres of riparian habitat along these drainages, with 601 acres along Arroyo Chico and 523 acres along Rio Puerco. Most of the native cottonwoods and willows have disappeared from these riparian areas and the invasive saltcedar and Russian olive are common in some areas.
Upland plants, such as rabbitbrush, have moved into some of the riparian areas. However, native vegetation is evident and increasing in some areas due to the exclusion of livestock or limitations on grazing. Vegetation in these areas typically grows in zones from wetter to dryer, starting with sedges and rushes common in the wettest zone and willows, grasses, saltcedar, rabbitbrush, and salt grass growing in progressively dryer areas. A few scattered remnant cottonwoods are present (BLM 2000c).
Proper-functioning condition (PFC) surveys were first conducted on FFO lands in 1994. During 1994, surveys took place on 3 tracts of the San Juan River, 9 tracts of the La Plata River, and the BLM portions of Largo Canyon, Carrizo Canyon, Palluche Canyon, La Jara Canyon, Gobernador Canyon, Kutz canyon, Pump Canyon Ditch Canyon, Blanco Canyon, and Simon Canyon. Of the river tracts, 2 were rated as PFC, 3 were rated as functioning at risk (FAR) with an upward trend, 6 were rated as FAR with no apparent trend, and 1 was rated as non-functional (NF). Of the intermittent and ephemeral systems, 1 was rated as PFC, 10 were rated as FAR with an upward trend, 6 were rated as FAR with no apparent trend, 2 were rated as FAR with downward trend, and 15 were rated NF. All of
Lake Horse Trail system is accessed from the park. Other special recreational areas are located on Simon Mesa and along the Pine River and the San Juan River. Recreation on the New Mexico portion of Navajo Lake and on the San Juan River below the dam is administered by the New Mexico State Parks and Recreation Division. Above the dam, Sims Mesa and Pine River Recreation Areas have camping, fishing, marina, and boat access to the lake. Below the dam, fishing and camping occur at San Juan River Recreation Area, and day use is facilitated at several sites along State Highway 511. (BLM manages Simon Canyon Recreation Area that has parking and camping facilities.)