Rocky Mountain Montane Riparian
The dark cones of Arizona cypress (Cupressus arizonica) are apparent in the photo center, among sycamore, chokecherry, and ash along the unseen watercourse, with a surrounding cast of pinyon pine, alligator juniper, and Arizona oak. Cypress are characteristic of this ecosystem, often in the company of maple (Acer negundo, A. grandidentatum).
Description
In this study, the Rocky Mountain Montane Riparian ecosystem is confined to watercourses at 5000 - 7000 feet. Although the ecosystem is flatter than most, it is hardly level: 52% of the ecosystem is found on slopes less than 10 degrees (18% slope), with 48% exceeding 10 degrees.
In this study, the ecosystem is defined not only by the presence of particular riparian species such as Arizona cypress, sycamore, maple, and canyon grape (Vitis arizonica), but also by the absence of these species outside of the watercourse. Hence, areas which are relatively mesic yet not distinctive are not mapped as part of the ecosystem. A good example of an excluded area would be Pinery Canyon in the Chiricahuas, which is home to a good deal of pine and Douglas fir at relatively low elevation, but only scattered sycamore.
In terms of the US Forest Service Potential Natural Vegetation Type, the area mapped is more similar to the Montane Willow Riparian System than the Gallery Coniferous Riparian Forest. In terms of the National Vegetation Classification System (NVCS), the area mapped is part of the Rocky Mountain Lower-Montane Riparian ecosystem. Lower elevation riparian strands are part of the North American Warm Desert Riparian ecosystem distinguished by a corridor of ash and sycamore and often hackberry (e.g, Leslie Canyon and Siphon Canyon). The boundary between these two ecosystems is around 5000 feet, where the canyons leave the mountain bedrock and open onto alluvial fans. Riparian strands above 7000 feet, characterized by spruce and/or aspen, are part of an Upper-Montane ecosystem that is too limited to map in this study.
One of the canyons included in the Rocky Mountain Montane ecosystem is Happy Camp Canyon in the Dos Cabezas, a relatively small watershed, yet provides a sharp contrast to the surrounding slopes of oak, pinyon, and mountain mahogany. There are several springs and strands of dense willow, walnut, elderberry, and canyon grape. (See photo below). In a similar manner, the leafy box elder of Howell Canyon is a surprise.
Most of the canyons mapped in this ecosystem are well known repositories of uniquely mesic habitat. They include:
Dragoons
Slavin Gulch
East Stronghold
Park Canyon
West Stronghold
Granite Spring
Middlemarch Canyon
Carlink Canyon
Chiricahuas
Cave Creek Canyon
South Fork Cave Creek
Brushy Canyon
Keating Canyon
South Keating Canyon
East Whitetail Canyon
Bonita Canyon
Rhyolite Canyon
East Turkey Creek
Horseshoe Canyon
Price Canyon
Rucker Canyon
Dos Cabezas
Happy Camp Canyon
Howell Canyon
Mineral Park (Gold Gulch)
Other Vegetation Classifications
The Rocky Mountain Montane Riparian ecosystem, as mapped in this study, is similar if not identical to the NVCS Rocky Mountain Lower Montane-Foothill Riparian Woodland and Shrubland. The shorter name was adopted because that is what appears in the Landfire (see crosswalk below).
The observed ecosystem includes elements of several vegetation types mapped or described in other classification schemes. In each of the six schemes referred to below, the * symbol marks the vegetation type most similar to the Rocky Mountain Montane Riparian ecological system.
And what is meant by ‘most similar’? For the USFS Plant "Habitat Type" (Potential Association), the USFS "Potential Natural Vegetation Type" (PNVT), and the Brown, Lowe, and Pase "Biome", the * symbol denotes the best fit based on the description of the Habitat Type, PNVT, or Biome. For the Landfire, ReGap, and USFS mid-scale classifications, which are presently mapped at a 30 meter resolution and were used in creating the map, the * symbol denotes the classification that was most commonly attributed Rocky Mountain Montane Riparian ecosystem, as mapped in this effort.
Landfire Existing Vegetation Type (EVT)
Rocky Mountain Montane Riparian *
USFS Mid-scale Dominance Type
(Note: the Coronado Mid-scale map did not map riparian habitat, and hence had no riparian vegetation type)
USFS Plant Habitat Type (Potential Association)
Arizona sycamore series (PLWR2 series)
USFS Potential Natural Vegetation Type (PNVT)
Montane Willow Riparian System
Brown, Lowe, and Pase Biome
Rocky Mountain Riparian Deciduous Forest
Southwest Regional GAP Ecological System
(Note: ReGAP did not map montane riparian habitat, and hence had no appropriate vegetation type)