Common (Translated Scientific) Name: (Rio Grande Cottonwood, Plains Cottonwood) / Stretchberry Flooded Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This mature riparian forest association is found in the San Juan and Rio Grande watersheds in northern and central New Mexico, the Animas River watershed in southwestern Colorado, and is likely present in the Pecos drainage farther to the east. It occurs along low-gradient rivers of wide lowland valleys at elevations from 1530 to 1800 m (5000-5900 feet). Sites range from relatively dry, elevated terraces that are rarely flooded, to more frequently flooded mid-elevation sidebars and island bars of low-gradient rivers. Soils are moist or dry, poorly developed Entisols or, where some soil development has occurred on older terraces, Inceptisols. Soil textures are coarse-loamy throughout the profile, or with sandy layers overlain by finer loam or silt. All soils have high plant-available water (8.5% on average), and the water table is usually within 2 m of the surface during the growing season. This community type is characterized by mature, often dense and closed canopies of Populus deltoides ssp. wislizeni or Populus deltoides ssp. monilifera with occasional Salix gooddingii in the subcanopy. Other trees may be present in the subcanopy but are not normally abundant. Populus deltoides saplings are rare or absent. The shrubs are well-represented to abundant (10-75% cover) and dominated by Forestiera pubescens var. pubescens with Rhus trilobata and Amorpha fruticosa common. In Colorado, Elaeagnus angustifolia and Tamarix ramosissima can also be present. The twining, woody vines of Parthenocissus quinquefolia and Clematis ligusticifolia can often be found among downed logs or wrapped around trees and shrubs. The herbaceous layer is sparse to well-represented (10-15% cover) and is a mix of grasses and forbs that reflect the relatively drier habitat. Overall, species diversity is high with 81 species recorded for the type (although 24-30% were exotics). As a keystone species, the reproduction of Populus deltoides after flooding (and sufficient subsequent base flows) is critical to the sustainability of this community.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The community is naturally distributed along the floodplains of larger streams and rivers but may be declining due to encroachment by exotic species and altered hydrologic regimes. Where it occurs along stream reaches that have been significantly altered in some way (i.e., jetty jacks, dams, and irrigation diversion), there is a wide range of soil and hydrological conditions in which this community occurs. Occasionally, floodplains may become highly altered, leaving the community far from the active channel, thus reducing flooding and stopping reproduction. With increasing disturbance from fire, the community becomes highly susceptible to further invasion by exotics, particularly by Elaeagnus angustifolia, Tamarix ramosissima, and Ulmus pumila. Elaeagnus angustifolia is common in most stands (particularly more mesic ones) and is the most probable successional exotic species. Effective restoration of these stands to enhance biodiversity, quality, and condition requires emulating a natural hydrological regime.

Similar NVC Types: No Data Available

note: No Data Available