Natural Resources Monitoring at Gila Cliff Dwellings National Monument
The Sonoran Desert Network monitors air quality, climate, groundwater, invasive exotic plants, landbirds, seeps, springs, and tinajas, streams, and vegetation and soils at Gila Cliff Dwellings National Monument. The results of this work can be found in a variety of publications and other information. The network also maintains species lists for the park.
Established by President Theodore Roosevelt in 1907, Gila Cliff Dwellings National Monument protects and interprets a complex of 15th-century Mogollon cliff dwellings and other associated prehistoric sites, and the diverse natural environment that attracted and supported these early civilizations. The location of these important prehistoric resources is directly related to scarce and important natural resources: the perennial waters and associated rich natural resources of the upper Gila River. The primary natural resource issues of concern at the park include invasive exotic plants and aquatic invasive species, such as American bullfrog (Lithobates catesbeiana) and crayfish (Orcontectes spp.), and the consequent decline, and even extirpation, of many native aquatic vertebrates.
Park Setting and Key Resources
Size: 216 hectares
Elevation range: 2,027–2,079 meters
Biogeography and physiography
Gila Cliff Dwellings National Monument lies in the Arizona–New Mexico Mountains ecoregion near the confluence of three major ecoregions in the American Southwest. This continental position—a transition between the Sonoran and Chihuahuan deserts on the east and west, and the Rocky Mountains and Sierra Madre to the north and south—is reflected in the monument's biodiversity. The monument includes steep but relatively shallow canyons, as well as portions of the channels and associated floodplains of the middle and west forks of the Gila River. It is part of the temperate forest biome. Average annual precipitation is 19.8 inches (504 mm).
Local geology and soils
The monument lies within an ancient caldera that collapsed following an enormous volcanic eruption. The surrounding mesas are composed of rhyolite, andesite, basalt, and welded tuffs interbedded with Gila Conglomerate. The floodplains and channels are composed of shallow alluvium from local deposition of these same materials. The park has not had a comprehensive soil survey.
Climate and hydrology
The climate of Gila Cliff Dwellings National Monument is typical of the Arizona–New Mexico Mountains ecoregion: highly variable, bimodal precipitation with a considerable range in daily and seasonal air temperature, and relatively high potential evapotranspiration rates. Approximately half of annual precipitation falls during summer thunderstorms, where maximum air temperatures often exceed 86°F and lead to violent (and often localized) rainstorms. The bulk of the remaining annual precipitation falls in relatively gentle events of broad extent, occasionally as snow.
Weather and climate data for Gila Cliff Dwellings National Monument and all other Sonoran Desert Network parks can be found at The Climate Analyzer, an interactive website that allows users to create custom graphs and tables from historical and current weather-station data. A weather and climate inventory was created for the Sonoran Desert Network in 2007. A more recent brief shows the magnitude and direction of ongoing changes in climate at Gila Cliff Dwellings National Monument.
The middle and west forks of the Gila River drain about 1,037,843 acres. Stream flow is highly variable and tightly linked to upstream weather events. Flooding is common, particularly following rain-on-snow events, spring snowmelt peaks, and intense localized summer thunderstorms.
Human habitation of the landscape
Human use of the monument area apparently has occurred for at least the past 2,000 years. However, the park's iconic dwellings were probably only occupied for perhaps 50 years during the 13th century A.D.
Protohistoric and historic use appears to have been dominated by the Chiricahua Apache during the 17th to 19th centuries, indicating a key cultural link with Fort Bowie National Historic Site and Chiricahua National Monument. During the historic period, homesteading, ranching, and guest ranching became dominant land uses in the area.
In addition to the cliff dwellings, contemporary and historic visitors were attracted to the area's magnificent wilderness, perennial waters, hot springs, and mild climate. Today, recreation is the primary human use of the Gila Cliff Dwellings landscape, with guest ranches, vacation cabins, and campgrounds distributed along the few roads and developed areas within the Gila Wilderness.
Amphibians and other aquatic invertebrates
Perhaps the most dramatic and alarming natural resource issue at Gila Cliff Dwellings National Monument has been the rise of non-native aquatic species, such as American bullfrog (Lithobates catesbeiana), and crayfish (Orcontectes spp.)—and the consequent decline, and even extirpation, of many native aquatic vertebrates.
Field surveys conducted from 2001 to 2003 failed to locate four species of amphibians that were historically common in the park: Mexican spadefoot (Spea multiplicata), Woodhouse's toad (Anaxyrus woodhousii), red-spotted toad (Anaxyrus punctatus), and Chiricahua leopard frog (Lithobates chiricahuensis). Declines in native amphibian species have been widely observed throughout the American Southwest, and are also attributed to habitat alteration, extended drought, increased UV radiation, non-native fishes, and chytrid fungus.
Invasive exotic plants
Biological invasions into new regions have increased at unprecedented rates in the past few hundred years. In the American Southwest, historic and current land management activities, such as livestock grazing and fire suppression, are thought to have made arid lands more susceptible to invasion and subsequent loss of native species and decreased biodiversity. In general, the southwestern semi-desert grasslands, savannas, and riparian community types are at greatest risk of invasion, due to modified disturbance regimes involving fire and herbivory. A biological inventory for the park detected 37 non-native species, comprising 8.5% of the flora. To date, tamarisk has not been detected within the park.