Maintaining the biological integrity of Lake Tahoe’s nearshore environment is a longtime goal of resource managers in the region and has been set forth in a variety of planning documents. Submerged aquatic vegetation is an important biological component within Lake Tahoe’s nearshore context. Knowing the status of submerged aquatic vegetation (SAV) populations at Lake Tahoe has become increasingly important to nearshore managers due to the introduction and spread of invasive species such as Eurasian watermilfoil (Myriophyllum spicatum) and curlyleaf pondweed (Potamogeton crispus). Aquatic invasive plants when left unchecked can affect fishing experiences, water quality, fish and wildlife habitat conditions, human and animal health, vessel navigation, and the recreation values of water bodies. For these reasons, this survey was conducted to assess the extent and distribution of submerged aquatic vegetation within Lake Tahoe’s nearshore zone.

Both in‐situ (field) diver survey data and the analysis of remote sensing data were used to characterize the status of aquatic vegetation. Quadrat and transect survey methods were employed for in‐situ surveys. These methods were effective for determining aquatic vegetation presence, composition, relative abundance and distribution. Field survey data were used in combination with 4-band imagery to map the distribution of submerged aquatic vegetation. A total of 102 transects and 482 quadrats were sampled to evaluate submerged aquatic vegetation communities within the study area. Data were separated into 4 strata: major tributaries, marshes, embayments, and open-water nearshore. Overall, percent SAV cover was greatest in the marsh stratum and lowest in the open-water nearshore stratum while acreage of SAV was the opposite.

Diver data in combination with high-resolution imagery along with hybrid mapping techniques were used to produce a map of submerged aquatic vegetation (SAV) within Lake Tahoe nearshore. Based on the 2023 analysis for native aquatic vegetation species, periphyton was the most abundant native SAV species detected and white-water buttercup was the least. For aquatic invasive plant species in 2023, curlyleaf pondweed was the most abundant species (14.7 acres) and Eurasian watermilfoil was less abundant (10.4 acres).

The full 2023 Nearshore Aquatic Plant Status Report can be accessed here.