Arikaree River NEON / ARIK

Arikaree River (ARIK) is an aquatic NEON field site located in the central plains of Northeastern Colorado. It has a large watershed size of 2631.8 km² (650,332 acres), and the land is managed by The Nature Conservancy. The area is sensitive to invasive plant species and disturbance, and NEON works with The Nature Conservancy to maintain Arikaree’s tall-grass prairie and diverse bird community. In the winter, Arikaree River is a free-flowing stream and dries into standing pools in the summer. The site is part of NEON's Central Plains Domain (D10). D10 has three terrestrial field sites and one other aquatic field site. ARIK is not colocated with a terrestrial site. [1] [2]

The Central Plains region is known for dry, hot summers and cold winters. Weather can change drastically in a short period of time. At this site, the mean average temperature is 10.4°C (50.7°F), and the mean annual precipitation is around 450 mm (17.7 in.). The combination of high elevation and mountain ranges mainly drives this region’s climate. The area can be subject to tornados, flooding, blizzards, and severe winter storms. [3] [4]

The geology at this site is characteristic of the Ogallala Formation which is comprised of alternating conglomerates and sandstones. [2]

The Arikaree River flows through a sand-alluvial basin and its bed and banks are composed mostly of sand. [1]

The Arikaree River drains a large watershed of 2631.8 km² (650,332 acres), but maintains the characteristics of a small wadeable stream throughout its length. Flow is fed primarily through surface run off, though some of the river comes from underground aquifers. Large peaks in flow can happen whenever strong, localized storms occur in the watershed, but generally the river dries up in the summer and leaves only pools. The Arikaree is thought to be one of the last free flowing rivers in the Great Plains. [1] [5]

The grassy shores of Arikaree River are dominated by grasses. Blue grama grass (Bouteloua gracilis), needle-and-thread grass (Hesperostipa comata), and big bluestem (Andropogon gerardii) grow strong here among others. [5]

Common species of fish collected through NEON's electrofishing, gill netting, and fyke netting protocols at ARIK are mosquito fish (Gambusia affinis), green sunfish (Lepomis cyanellus), and the fathead minnow (Pimephales promelas). Macroinvertebrates are also sampled at this site. [6]

ARIK is managed by The Nature Conservancy as part of Fox Ranch. It is maintained as an active cattle ranch but is managed to ensure a diverse tall-grass prairie and bird community persists. The Nature Conservancy is open for non-NEON research opportunities but is closed to public visitation. [5]

ARIK was designated as a NEON site in 2012. AOS operations began September 2014 and AIS operations started December 2015, but most data collection is not reflected until 2016.