LeConte Creek NEON / LECO

LeConte Creek (LECO) is an aquatic NEON field site in the northwest part of the Great Smoky Mountains National Park, located in eastern Tennessee. LECO is hosted by the National Park Service. LeConte Creek is a second-order wadeable stream with a series of steps and pools, consisting of many large granitic boulders and bordered by thick vegetation. It drains a 9.13 km² (2256 acre) watershed. The park is characterized by abundant rainfall, variable elevations, and an exceptional richness of biota hosted by closed-canopy deciduous old growth forests. As one of the largest protected areas in the eastern U.S., it is the most biodiverse park in the national park system and the most visited. LECO is part of NEON Domain 07 - Appalachians & Cumberland Plateau, which includes eastern Tennessee, most of Kentucky, southern Ohio, and parts of North Carolina, Georgia, Indiana, and Illinois. D07 includes four other NEON field sites, including three terrestrial sites and one additional aquatic site. LECO is colocated with the GRSM terrestrial field site. [1]

LeConte creek is found in mountainous terrain of the Great Smoky Mountains National Park. The park’s altitude variation simulates the climate and habitat changes you would experience traveling north or south across the eastern United States. The cool, moist environment found in higher elevations is juxtaposed against the drier, warmer lowlands. Temperature ranges are dependent on elevation and can vary 6-11°C (10-20°F) from mountain base to top. Average annual rainfall also varies with these elevation changes, ranging from approximately 1400 mm (55 in.) in the lower valleys to over 2160 mm (85 in.) on some of the highest peaks. Mean annual temperature is 13.1°C (56°F) and mean annual precipitation is 1375 mm (55 in.). With the exception of the Pacific Northwest, this park receives more annual rainfall than anywhere else in the contiguous United States. This heavy rainfall can cause extreme weather events such as flash flooding, particularly in the spring and summer months. During fall and winter, winds can become strong and damaging, reaching up to 80-100 mph as a result of a phenomenon known as mountain waves. [7]

The geology at LECO consists of alluvium, which is sand, clay or silt that was deposited relatively recently by a stream or other body of running water, as a sorted or semi-sorted sediment. [2]

Soils at this site are alluvium and highly weathered compared to other regions in the eastern United States. Typical substrates in the creek are mostly cobbles and coarse sediments. [4] [15]

LECO is a second-order, wadeable, high-gradient stream with an average fall of 10%. The creek contains numerous falls and rapids and a few deep pools and shoals. The stream comes to its only natural barrier at Rainbow Falls at an altitude of 1318 m (4326 ft), where the water makes a 26 m (85 ft.) drop. The flow is frequently interrupted by the heavy presence of small to large granitic boulders and is intercepted by falls and rapids. Hydrologic conditions can change rapidly as this area can received up to 85 inches of annual rainfall. [1] [3]

The area surrounding LECO is home to one of the largest stands of deciduous old growth forests in North America. Vegetation at LECO creek follows typical riparian vegetation and canopy cover which exists in a nearly homogenous pattern across the area. The site is dominated by tall deciduous and coniferous trees forming the canopy, and thick rhododendron bushes enclose along the edges of the stream reach. [1] [8]

LECO is surrounded by the highly biodiverse Great Smoky Mountains National Park. Perch (Perca) and rainbow trout (Oncorhynchus mykiss) can be found at this particular site in addition to other creeks in the park. The abundance of salamanders (Urodela) is exceptional in and around the waters of the creek, with around 30 species recognized to inhabit the area. At LECO, NEON conducts biological sampling of fish and macroinvertebrates. [4] [9] [10]

Designated as a national park by the U.S. Congress in 1934, the Great Smoky Mountains National Park was officially dedicated by President Franklin D. Roosevelt in 1940. This designation was historically significant as it was the first national park paid for in part by the federal government. GRSM encompasses a rich mosaic of historical use including human influence from prehistoric Paleo Indians, 1880s European settlement and 20th century loggers. Prior to its establishment as a national park, many historic species were eradicated from the ecological framework including bison, elk, mountain lion, gray wolf, red wolf, river otter, and several species of fish. The extraordinary biodiversity exhibited in the park’s 2108 km2 (814 sq. mi.) of plant-covered, gently-contoured mountains led to its designation as one of the first UNESCO World Heritage Sites in 1983. The North American deciduous old growth forest was plagued by wildfires in late 2016, burning more than 10,000 acres of the park, including areas in the NEON sites. [8] [14] [16] [17]

LeConte Creek is incorporated in the Great Smoky Mountains National Park, making it a hotspot for ongoing ecological studies. Management decisions are informed by available scientific data. The park encourages scientists and students from a multitude of institutions and organizations to contribute to current research, which is ultimately accessible to the public. Scientists from these institutions and organizations focus their areas of research on acid deposition, vegetation communities, soil quality, water chemistry, freshwater communities, and climate change. LeConte Creek has been an enduring draw for visitors of the park. Of special interest is Rainbow Falls, which represents the single highest drop of water in the national park. [13] [14] [15]

NEON began data collection activities at LeConte creek in 2015 when the Airborne Observation Platform (AOP) was flown over both sites collecting lidar, hyperspectral, and high-resolution RGB ortho-photos of the surrounding vegetation and landscape. Observational sampling also began in 2015, with two full seasons of organismal and biogeochemical data collected before a significant wildfire in 2016. Fortunately, the fire caused little damage to all data collection sensors except for the soil sensors, which suffered dramatic damage. [18]