Health Assessment Approach and Methods

Monitoring the status of the Ecological Health Assessment (EHA) Study Area is essential for helping managers detect change over time, understand why those changes may be happening, and identify and prioritize strategies to address threats. However, this project also had the explicit goal of trying to answer the question, “Has the Natural Communities Conservation Plan/Habitat Conservation Plan (NCCP/HCP) met its goals in the time since the Reserve was established?”

This assessment considered the condition and trends of species and communities deemed good “indicators” of ecological health (see below) using metrics that resource experts felt revealed something important about that indicator’s health.

Each chapter assesses trends, conditions, and confidence levels for each metric, then for the indicator overall. Where information was insufficient to draw conclusions, chapter authors and participating experts were encouraged to use their best professional judgment.

The chapters also summarize related stressors, inventory and monitoring efforts, surveys, and research. They provide summaries of the current state of this combined knowledge, documenting the methods by which assessments were made as well as data gaps and potential next steps to improve our collective understanding.

“Needs statement” chapters were developed for those indicators deemed potentially important for measuring ecological health but for which there were not enough data or capacity to do a full assessment. This information can be used to create monitoring programs or support data collection so that they may be included in future updates.

“Ecological health” is a broad, complex concept with no single, agreed-upon definition. In this report, we chose to define it in terms of processes, resiliency, and diversity rather than specific qualitative or quantitative goals.

Specifically, a healthy Natural Communities Coalition (NCC) Reserve System supports:

• No net loss of long-term habitat “value” as defined in the NCCP/HCP.*
• Diverse native species assemblages, community structures, and ecosystem functions resilient to stressors.
• The inherently dynamic nature of these ecosystems, which permits a shifting mosaic of vegetation communities and fluctuations in species’ populations over time within a range that allows conserved species to persist and recover from perturbations.

*Value is defined as the potential contribution habitat areas could make to the long-term viability of target species and to the overall reserve design (Section 3.4 Habitat Evaluation, NCCP/HCP Parts 1 and 2).

An initial list of approximately 70 potential ecological health indicators was narrowed down based on the following criteria, which were considered to meet the overall purpose and goals for this project, are meaningful or important to our primary audiences, and help us measure ecological health as previously defined.

1. The indicator is present on the lands within the geographic scope of this project.
2. The indicator is a species/habitat/process covered under the NCCP/HCP or other Nature Reserve of Orange County land managers’ conservation initiatives (including threatened and endgangered species recovery plans).
3. Information and expert opinion are available and can be drawn upon to try to determine the indicator’s condition or trend.
4. The indicator is useful for measuring ecological health and/or tracking change over time in some meaningful way (e.g., an indicator of ecosystem integrity and function, natural disturbance regimes, or resilience).
5. The indicator can be used to build public affinity and interest and/or is of particular interest to partners/stakeholders, decisionmakers, nearby land managers, or tribes.

The selection of final indicators largely came down to NCC partners’ staff capacity to develop metrics, analyze data, and write up the results. (In some cases, while the human capacity was there, data to inform an assessment were not.)

The ways condition, trend, and confidence were assessed for an indicator and its metrics can be found in each chapter. However, the general approach was as follows:

• An overall condition of good, caution, significant concern, or unknown was determined by averaging the conditions of the individual metrics.
• An overall trend of improving, no change, declining, or unknown was similarly assigned, based on average trends of the individual metrics.
• A confidence level of high, moderate, or low was assigned based on the quality, quantity, and recency of available data and the degree of best professional judgement (if required) to make condition and trend assessments.

The overall condition, trend, and confidence determination was derived by averaging the scores of these metrics. Each condition, trend, and confidence level described with one word had a corresponding numerical score.

Condition

• Good = 100
• Caution = 50
• Significant Concern = 0
• Unknown = no score

Trend

• Improving = 100
• Unchanging = 50
• Declining = 0
• Unknown = no score

Confidence

• High = 100
• Moderate = 50
• Low = 0

Scores were combined using a simple (unweighted) average calculated by adding the scores for condition, trend, and confidence and dividing by the number of metrics used. (To avoid unfairly/inaccurately lowering the overall average, “unknowns” are not scored or included.)

Where the average of the metrics fell within the following ranges determined the condition, trend, and confidence level.