Meadow Reconnaissance

Summer in American Rivers’ California regional office means field season – or, as it should more aptly be named, meadow season. Going on three summers, and with the continued support of the National Fish and Wildlife Fund (NFWF), American Rivers’ staff has assessed meadows for restoration prioritization on a watershed scale. This summer, over 80 meadows in the Carson and Truckee River watersheds will be surveyed using the Rapid Assessment Scorecard, a collaborative design with UCDavis.

Why does American Rivers work on meadows? Meadows store spring floodwaters and release cool flows in late summer; they filter out sediment and pollutants, produce high-quality forage and provide habitat for rare and threatened species.

Each summer of meadow work brings unique challenges and creative solution finding. New this year, American Rivers’ called upon our friends at LightHawk, who donated a pilot, a Cessna 172 and an early morning to fly over the meadows of the Carson River watershed. Relying on GPS and aerial imagery we flew over meadows we planned to asses. The flight allowed us to confirm whether an on the ground visit would be useful…or not. To prepare for meadow assessments, we rely heavily on aerial imagery.

Displayed in two dimensions, aerial imagery does have limitations. Areas that appear uniformly colored and textured are often classified as meadow, without taking into account key attributes that define meadows: slope and vegetation cover. Mountain meadows, by definition, have a low slope gradient (meaning they are mostly flat) and are covered by herbaceous species (grasses and flowers) that rely on surface water and shallow ground water. Mountain meadows may contain localized stands of woody vegetation (willow, alder), but herbaceous species dominate.

Bull Canyon “meadow” – pictured below – exemplifies the benefits of an aerial fly-over. Compare the two images below. The aerial image on the left, which we viewed from our GIS computer, shows the supposed meadow outlined in orange. The picture on the right, taken during our LightHawk flight, shows the same area. Is it a meadow?

meadow reconnaisance

Decidedly not.

Per our earlier definition of mountain meadows, Bull Canyon “meadow” is too steeply sloped and contains too much woody vegetation (the rougher/fluffy green texture is willow) to be considered a meadow. Had we relied solely on the 2d image supplied through our GIS software, we would have hiked eight miles to determine that this area, though picturesque, does not meet the criteria for assessment. Viewed live, from above, we were able to quickly check Bull Canyon off our list of meadows to assess. In total, the LightHawk flight confirmed that eight meadows were, in fact, not meadows at all. Eliminating these sites from our assessment allows us to more efficiently concentrate our time and resources on confirmed meadows of the Carson River watershed.

We are grateful to LightHawk for donating their services, and look forward to continuing to explore new tools and opportunities to enhance our summer meadow work.