Tahoe yellow cress is a flowering perennial plant in the mustard family that grows on Lake Tahoe’s sandy shorelines and nowhere else in the world. Over the last two decades, habitat threats to Tahoe yellow cress have been managed and successfully reduced by federal, state, local, and private sector partners on the Tahoe Yellow Cress Adaptive Management Working Group. This group has protected the plant and its habitat with the 2002 comprehensive conservation strategy. Because of the collaborative work of this group, and the robust conservation strategy, in 2015, the U.S. Fish and Wildlife Service determined that the plant did not require additional protections under the federal Endangered Species Act. Tahoe yellow cress populations are highly responsive to changing water levels in Lake Tahoe, thriving on exposed sandy beaches and natural areas when lake levels are low. When the lake level is high, populations decrease because these habitat areas are submerged. However, the Conservation Strategy provides actions such as seed bank programs, increased fencing around population sites, and planting of additional areas, to assure that Tahoe yellow cress populations increase when lake levels drop. Tahoe yellow cress is monitored by partners around the Tahoe Region at all potential population sites as part of a Region-wide survey each year in September.

Status

Number of sites occupied by Tahoe yellow cress during the survey period from 1979 to 2019. The number of occupied sites is highly correlated to the lake level, where high lake levels result in fewer occupied sites.

Evaluation Map

Tahoe Yellow Cress Population Sites

2019 Evaluation

Status
Somewhat Worse Than Target
Trend
Little or No Change
Confidence
Moderate
View Evaluation

Applicable Standard

VP21: Maintain a minimum of 26 Rorippa subumbellata population sites.

Key Points

  • In 2019, Lake Tahoe was nearly full, and there were 22 population sites occupied with Tahoe yellow cress which is 85 percent of the target. 
  • Lake levels significantly impact the number of occupied sites, and the 22 occupied sites are a considerable improvement upon the number of occupied sites (less than 10) during the sustained high lake levels from 1995 to 2000.
  • Tahoe yellow cress can only be found in beach and rocky habitats around the shore of Lake Tahoe. Because these habitats are greatly reduced during high lake levels, Tahoe yellow cress numbers are closely related to lake levels.
  • Despite recent low numbers, the population appears to be stable and has been removed from the endangered species candidate list.

Delivering and Measuring Success

EIP Indicators

Example EIP Projects

Local and Regional Plans