Adaptive Management


Threshold Standard Review and Amendment

In the 30 years since initial adoption, a general consensus emerged by 2015 that the threshold standards needed to be reviewed and brought current with new science and emerging understanding of ecosystem changes driven, in part, by climate change. TRPA engaged the Bi-State Tahoe Science Advisory Council to prioritize a comprehensive update of threshold standards.

Threshold standards are long-term goals for the Region to be achieved through a wide range of implementing means. The Environmental Improvement Program, established in 1997 and made part of the plan’s implementing element, accelerates Regional Plan implementation through investment in capital projects, research, and monitoring. Attainment of the threshold standards is acknowledged to be a continuing process requiring the cooperation of all sectors with interests in the Region, the States of California and Nevada, the Federal government, local jurisdictions, and the private sector, and will likely not be fully realized until well after the implementation of the Regional Plan.

The approach to keeping threshold standards and the Regional Plan up to date is based on a system of rigorous inputs and adaptive management recommended by the Bi-State Tahoe Science Advisory Council in 2017. The elements of the adaptive management system start with establishing or amending threshold standards and assessing and reporting progress toward those standards using a reporting framework, that may include interim performance measures and monitoring program indicators that support management decision making to promote threshold standard attainment and maintenance. In 2017, the Tahoe Science Advisory Council reviewed the best practices of nine other large natural resource restoration management systems and identified a core set of recommendations for organizing and implementing the system to better support adaptive management in the region and accelerate threshold standard attainment (Tahoe Science Advisory Council (TSAC) 2017).

The adaptive management or continuous improvement “plan-do-check-adjust” approach is “a systematic approach for improving resource management by learning from management outcomes (Williams et al. 2009; Tahoe Science Advisory Council (TSAC) 2017).” The threshold standards and the Regional Plan represent the “plan” function. The long-term goals (threshold standards) are set and kept up to date through periodic review and amendment as needed. Completion of public and private projects, programs, and proposals corresponds to the “do” function. The “check” function is carried-out through monitoring and reporting which is then used on an ongoing basis to “adjust” by making changes to the “plan.” Providing robust information to support as close to continuous threshold evaluation as possible is the key to keeping both threshold standards and Regional Plan policies and implementation strategies current. That is, as new information, knowledge, and resources become available the threshold standards and the Regional Plan may be updated to ensure they continue to reflect current science and best practice.

The threshold and Regional Plan adaptive management system structure is designed with the information needs of the “plan-do-check-adjust” approach in mind. The adaptive management system structure draws heavily from best practice and integrates four elements: (1) conceptual models – that ground threshold standards in the scientific understanding of ecosystem function, (2) results chains – that link management actions to desired outcomes (threshold standards), (3) management actions – that are the implementation strategies rooted in results chains to promote attaining and maintaining clearly articulated, specific and measurable goals (threshold standards, and (4) monitoring, evaluation, and learning – which provides the structure for incorporating new information into the design of policies, programs, and other means to accelerate threshold attainment.

The adaptive management system structure provides a framework to organize information in a manner that better serves the needs of managers and is more coherent to stakeholders. The conceptual models can be distilled and presented as straightforward summaries of the scientific understanding of the system. The results chains communicate to stakeholders how management actions contribute to standard attainment. The monitoring, evaluation, and learning platform identify how progress is tracked and how results inform future management action.


Threshold Standard Specifications

Standard formulation – whether long-term threshold standards or interim performance measures --should be consistent with best practice and should enable objective evaluation of conditions relative to the adopted standard. Standard formulation will include three qualities:

  • Specific - The standard establishes a specific numeric target, and benchmark/baseline values are documented where necessary.
  • Measurable – The standard has clearly defined indicator(s) that link to the standard, and there are practical ways to objectively and accurately measure progress towards attainment.
  • Outcome-based – Standards establish a desired condition for an environmental end state. Standards do not establish a means to achieve the desired outcome.

Formulating specific and measurable standards enables objective evaluation of each standard. Outcome-based standards ensure that threshold standards (consistent with the Bi-State Compact definition) focus on the long-term or end-state goals for the system, rather than being prescriptive about the actions to achieve or maintain the goals.

When the first set of threshold standards were adopted, they were organized into nine categories. The Bi-State Compact requires the agency to establish threshold standards for five categories (Air QualityWater QualitySoil ConservationVegetation Preservation, and Noise) and four others (FisheriesRecreation, Scenic Resources, and Wildlife) were identified through the collaborative process to identify the threshold standards. The nine categories provide a useful framework for explaining the goals of the threshold standards, but the goals established by the threshold standards are not bound by the reporting category in which the standard resides. Threshold standards span multiple of the existing categories.

The full adaptive management cycle includes review of implementation actions and periodic review of overall program goals. Periodic review of threshold standards serves to ensure that the desired conditions are informed by the best science and continue to reflect relevant values.


Guiding Principles

The following principles will guide the review and update of threshold standards.

  1. Protect ecosystem processes, structures, and functions: Restoring and maintaining the qualities of the Region requires identifying the system processes, structures, and functions that create those values.
  2. Science-based: Standards and management programs are updated to remain consistent with the best science.
  3. Manage as a System: The standards and adaptive management system reflect ecosystem level thinking at various scales.
  4. Specific and Measurable: Standards that are specific and measurable enable objective evaluation and provide meaningful information to managers and stakeholders.
  5. Informative: The threshold evaluation and reporting system should be designed to provide information that improves management and accelerates threshold attainment.
  6. Feasible: The cost of monitoring and evaluation program that supports the threshold standard system is within the Region’s collective monitoring resources.

Threshold standards will be amended where the threshold standard review finds that it is appropriate and necessary to do so. Instances where amendment is appropriate and necessary include, but may not be limited to:

  1. Two or more threshold standards are mutually exclusive; or
  2. Substantial evidence to provide a basis for a threshold standard does not exist; or
  3. A threshold standard cannot be achieved; or
  4. A threshold standard is not sufficient to attain or maintain the significant value for which it was identified; or
  5. A threshold standard is inconsistent with the adaptative management structure.

TRPA maintains a monitoring and evaluation program to determine progress towards attainment of threshold standards and to provide the basis for such review and amendment of the threshold standards pursuant to the foregoing criteria.