Basics
Tahoe Yellow Cress (Rorippa Subumbellata)
Tahoe Yellow Cress
Action
Program
Each Unit (number)
Tahoe Yellow Cress (Rorippa Subumbellata)
The number of population sites that are maintained as suitable habitat for sensitive plant species (as determined by a qualified expert).
This Indicator is reported in the following LT Info areas:
Accomplishments
The relationship between the number of sites occupied by Tahoe yellow cress and the level of Lake Tahoe as measured in September (USGS Tahoe City gage 103370000) during the survey period from 1979 to 2014. Lake level (blue line) is in feet of elevation, Lake Tahoe Datum (LTD). Fifty sites were surveyed; six years have no survey data, and two years with less than 60 percent survey were excluded. The black dashed line indicates that the number of sites occupied has increased over time. The number of sites surveyed increased from 32 in 1979 to 50 by 2009. Source: Stanton et all. 2015.

No Subcategories for this Indicator.

Program Tahoe Yellow Cress Monitoring

Approach

Knowledge of TYC distribution has been developed through shorezone surveys since 1979. Before 2000, surveys followed a general protocol and were completed at various times during the summer. Since 2001, surveys are conducted the first week of September following a standardized protocol. During the first survey in 1979, 32 TYC sites were surveyed; this has since grown to 55 sites. A survey “site” is defined as a stretch of public beach, adjacent private parcels, or adjacent parcels under a combination of private and public ownership. Surveys include stem count estimates as a measure of TYC abundance because clonal growth makes it impossible to distinguish individuals. The amount of available shorezone habitat for TYC fluctuates widely with changes in lake level, with high lake levels leaving little habitat. On average, over 70% of surveyed sites are occupied when the lake is below 6,225 ft. in September, but less than 40% are occupied when the lake level is above 6,228 ft.

To download all of the Tahoe yellow cress data on this page please see Tahoe Open Data.

Partners

Associated Programs data not provided.