Background & Methodology

Overall Process

To begin scoring a species, the user selects a target region and time period for climate change projections that is relevant to management goals. The targeted region can be a management unit, an ecoregion, or the entire range of species, but the boundaries for a set of scores cannot encompass disparate climate projections (i.e., multiple estimates of exposure).

Once selected, the user collects information on projected temperature and precipitation as well as related phenomena such as snowpack, sea level, and disturbance for the target area. Additional projections are also collected for migratory species. Next, the user collects data on the species to be scored from literature or expert sources.

            Key Principle: Responses relating to situations where a species is expected to benefit from future conditions have a value of -1 and signify resilience. Responses relating to expectations of less favorable situations have a value of +1 and signify vulnerability.
        

Assessment Categories

The SAVS tool evaluates species vulnerability across four key categories:

1. Habitat (7 questions)

Examines changes to breeding and non-breeding habitat areas, habitat components, quality, and species' dispersal abilities. Also considers migratory habitat requirements.

2. Physiology (6 questions)

Assesses physiological thresholds, temperature-dependent processes, disturbance exposure, activity limitations, resource flexibility, and metabolic requirements.

3. Phenology (4 questions)

Evaluates potential mismatches between species cues, timing of critical events, proximity of resources, and reproductive flexibility.

4. Biotic Interactions (5 questions)

Considers changes to food resources, predators, symbionts, disease prevalence, and competitors under climate change scenarios.

Scoring System

Scores are calculated for each category and overall vulnerability using specific formulas that account for the different number of questions in each category:

Habitat Vulnerability =
(Sum positive values × [5/7]) + (Sum negative values × [5/6])

Physiology Vulnerability =
(Sum positive values × [5/6]) + (Sum negative values × [1])

Phenology Vulnerability =
(Sum positive values × [5/4]) + (Sum negative values × [5/3])

Biotic Interaction Vulnerability =
(Sum positive values × [1]) + (Sum negative values × [1])

Overall Vulnerability Score =
(Sum positive values × [20/22]) + (Sum negative values × [20/19])

Uncertainty Assessment

Each question includes an uncertainty component where users indicate whether information is "adequate" or "not adequate/conflicting." Uncertainty scores are calculated as:

Uncertainty Score = Sum of uncertainty values / Total number of questions

Score Ranges and Interpretation

Overall Score Range: -20 to +20
Category Score Range: -5 to +5
Positive scores: Indicate vulnerability to climate change
Negative scores: Indicate resilience to climate change
Zero or near-zero: Neutral effects or balanced impacts

            Important Note: Although the scoring system uses a linear scale for multispecies comparisons, this does not translate to a linear biological effect. Maximum or minimum scores are unlikely because some criteria only apply to certain species and traits reflect both resilience and vulnerability.
        

Caveats and Restrictions

he effectiveness of this scoring method and the applicability of the information derived from this process depend upon the quality of data used to conduct the scoring process. Scoring may require substantial amount of input data both regarding species vulnerability and future climate scenarios [A System for Assessing Vulnerability of Species (SAVS) to Climate Change]. The scoring tool was designed to be applied at the scale of a management unit and to accommodate a single climate zone (i.e., a uniform set of climate projections). Additional regional climate information needs to be integrated into the scoring system for migratory species that spend a significant portion of their lives outside the targeted region Scores are not weighed by the relative influence of various criteria and it is up to the user to determine the relative importance of individual criterion to species persistence. Scores, scaled from -20 to +20, represent relative vulnerability and are not an absolute or linear measure of vulnerability. In addition, the quality and quantity of information varies for individual species. An uncertainty score is included to account for this variation. Uncertainty also exists in predictions for future climates, which can influence the outcome of the scoring process.

Uncertainty scores should be taken into account when interpreting results. A high uncertainty paired with a neutral score may indicate a lack of information rather than a realized neutral effect of climate change. Species with high uncertainty scores may be good candidates for further research and monitoring.

Background & Methods