Monitoring Methods

Tahoe RCD, in coordination with other program partners, facilitates a variety of survey and monitoring activities to identify new AIP control sites, determine the appropriate AIP control method to be used for the removal of AIP, document pre- and post-treatment conditions, and assess the success of current methodologies and strategy. The types of AIP monitoring currently taking place in the Lake Tahoe Region can be categorized broadly into the following four categories: (1) Pre-Treatment Monitoring, (2) Post-Treatment Monitoring and Control Maintenance, (3) Lake Tahoe Aquatic Plant Monitoring Program and (4) The Eyes on the Lake Program.

Pre-Treatment Monitoring

Pre-treatment monitoring includes general monitoring of the potential submersed aquatic plant habitat area, detecting infestations, scheduling/prioritizing areas to be treated and identifying which method(s) to implement within the area, and finally monitoring and characterizing the area to be treated prior to control implementation to ensure the appropriate methodologies are used and
installed/established to protect resources in the area. Resource protection includes knowledge of the substrate, existing subsurface utilities or hazards, native plant and animal species present in the area, cultural resources present in the area, public use and access of the area, and the existing quality and characteristics of the water in which the control action will occur.

Post-Treatment Monitoring and Control Maintenance

Post-treatment monitoring tracks whether treated areas have fully removed the infestation, and what type of plants or plant fragments remain. If treated areas are monitored and the monitoring identifies new plant growth, those areas can be re-treated, or maintenance measures applied to eradicate the infestation or prevent extensive re-infestation of species at a higher cost of control. If the affected areas can be maintained with lower levels of control effort, the cost of treatment and the potential for infestations to spread to other areas are minimized.

Post-treatment monitoring is conducted immediately following control implementation and annually following control implementation. This monitoring includes identification of the area being monitored and the control method(s) applied, the period of control implementation, and the post treatment success rate. If aquatic invasive species are identified during post-treatment monitoring, the species and number of plants are noted, including approximate plant size/maturity, and the location of the plants within the treatment area. Monitors also provide a recommendation as to maintenance methodology to keep reinfestation from occurring. Post-treatment monitoring is not only used to monitor treated areas to ensure they are maintained and avoid expensive and intensive control actions, this monitoring will also be used to identify the success rate of the control methods used, how the control method was or was not successful, potential reasons why new plants have re-established in the treatment area, and potential changes or improvements to the methods previously used.

Lake Tahoe Aquatic Plant Monitoring Program

TRPA coordinates annual lake-wide monitoring following the Lake Tahoe Aquatic Plant Monitoring Program: Aquatic Plant Monitoring and Evaluation Plan. The Action Agenda recommends monitoring strategies such as a broad spectrum near-shore-wide census every two years for six years, followed by once every five years, and in situ diver survey transects and drone surveys at 25 priority locations in intervening years.

Eyes on the Lake Program

The League to Save Lake Tahoe oversees the Eyes on the Lake citizen science program in which League staff train community members how to identify and report the location and presence of AIP in Lake Tahoe’s waters.

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