Sycamore Creek NEON / SYCA

SYCA is located in the Sonoran Desert, which is characterized by a semi-arid, hot climate. Winters are short and mild, while summers are long and hot. The mean annual temperature is 20.7°C (69.3°F). The Sonoran Desert is wetter than most deserts, and SYCA has a mean annual precipitation of 408.9 mm (16 in.) each year. Summers are exceptionally warm, often exceeding 40.5°C (105°F) for many days consecutively and can reach up to 48.7°C (120°F). Precipitation has a bimodal distribution in this region, with gentle, quenching rains in the winter and fierce thunderstorms during the summer monsoons. However, there are many months between the wet seasons, so both plants and animals in the area are adapted to arid conditions. The lack of prolonged freezing temperatures in the winter means that columnar cacti and other large succulents are common. Dry desert air and smaller canopy height common in the region results in considerable diurnal temperature changes. During any season, day to night temperatures can be a difference of up to 15°C (59°F) or more. [8] [9]

Geological formations that make up the Sycamore Creek Watershed include mostly volcanic basaltic flows composed of Precambrian metamorphic and igneous rocks. [3] [4]

Soils consist of unconsolidated sediments and are shallow and overlying. The substrate of the creek is composed of boulders and sand. [1] [12]

The hydrological patterns of Sycamore Creek are almost exclusively driven by a bimodal precipitation regime which consists of summer monsoon rains (June-September) and winter rains (January-March). As a desert stream, SYCA often has a low discharge rate (0-20 cfs) during the driest times of the year and up to 2000-3000 cfs during peak flows. Monsoonal rains in the summer months often result in intense flash floods. These storm events often drastically alter morphology of the stream by displacing gravel and compressing or contracting the channel. Annual precipitation for the SYCA watershed fluctuates between 390-510 mm (15-20 in.) and significant evapotranspiration can cause sections of the creek to dry up completely during spring and fall months. [1] [2] [6]

Sonoran Desert scrub flora dominates the Sycamore Creek site and includes saguaro cacti (Carnegiea gigantea), prickly pear (Opuntia spp.), velvet mesquite (Prosopis velutina), and palo verde (Parkinsonia microphylla) on the upland slopes. Along the creek’s edge, riparian tree species appear including Fremont’s cottonwood (Populus fremontii), Goodding's willow (Salix gooddingii), Arizona sycamore (Platanus wrightii), Arizona walnut (Juglans major), and Arizona ash (Fraxinus velutina). Prominent wetland species include Torrey’s rush (Juncus torreyi), southern cattail (Typha domingensis Pers.), chairmaker's bulrush (Schoenoplectus americanus), and knotgrass (Paspalum distichum). [1] [2]

Native aquatic fauna that dominate the Sycamore Creek site include longfin dace (Agosia chrysogaster), desert sucker (Catostomus clarkii), Sonora sucker (Catostomus insignis), lowland leopard frog (Rana yavapaiensis), Sonoran mud turtle (Kinosternon sonoriense), and black-necked garter snake (Thamnophis cyrtopsis). SYCA also has a high prevalence of a non-native fish species, the fathead minnow (Pimephales promelas). The two species that are observed and collected for NEON aquatics observation sampling (AOS) at SYCA are longfin dace and fathead minnow. [5]

Sycamore Creek experiences powerful disturbance regimes in the summer during monsoon season in the form of flooding. These flash floods topple and kill trees, abrade the riverbed, and significantly alter the path of the channel while eroding and cutting banks. Sycamore Creek has an extensive, interdisciplinary research history including biology, ecology, geology, fluvial geomorphology, and botany. It has been an active LTER site for countless researchers and has served as a principal investigation site for Arizona State University biology and ecology programs since the 1980s. [1] [10] [11]

Tonto National Forest, a USFS unit in Arizona at over 11735 km² (2.9 million acres), is the largest forest system in Arizona and the seventh largest in the United States. With over 3 million visitors each year, Tonto National Forest offers abundant resources for visitors including numerous recreational opportunities such as camping, boating, hiking, horseback riding, and mountain biking. The USFS manages Tonto National Forest with several key goals in mind. The USFS conducts research and management activities that support native flora and fauna (especially rare or endangered species), invasive species removal and monitoring, riparian resources protection, mining and grazing permitting, and wilderness areas management. [7]

Site characterization for Sycamore Creek commenced in February 2017. In October 2017, aquatic observation sampling (AOS) began at SYCA. A month later in November 2017, all aquatic instrumentations sampling (AIS) was set up and the site transitioned to full operations.