Updating Arizona's SGCN

In early 2020, a team of AZGFD species experts conducted a series of meetings to determine appropriate criteria for assessing species vulnerability. The 2012 SWAP criteria were used as a starting point (AZGFD 2012). The team determined that the criteria were still applicable and only minor refinements were made to remove unnecessary complexity and to provide more clarity in the criteria descriptions. The list of SGCN will be updated as additional data become available. The vulnerability criteria described below reflect those refinements and were used by AZGFD biologists to complete species evaluations. 

Species were scored for each of the seven vulnerability criteria detailed below. If a species ranked as “vulnerable” (i.e., score = “1”) under one or more of the seven vulnerability criteria, it was included in the SGCN list. Ranks were not additive. 

Species were considered to have “unknown status” if there were insufficient data to determine the species’ vulnerability under one or more of the criteria (i.e., if none of the seven criteria were scored as “1,” but one or more of the seven categories scored “0”). The following details each of the seven vulnerability criteria:

1. Extirpated Status

Species that historically occurred in Arizona, but are thought to no longer exist here, although populations continue to persist in other states or in México.

2. Federal or State Legal Status

The legal status of each species, subspecies or distinct population segment determines this criterion score. Vulnerable species include vertebrates, mollusks, crustaceans, or plants that are currently listed federally under the ESA as endangered or threatened, including those populations considered essential or nonessential experimental under section 10(j) of the ESA; recently delisted species that are undergoing post-delisting monitoring; species with a signed Candidate Conservation Agreement (CCA), Candidate Conservation Agreement with Assurances (CCAA), Conservation Strategy and Assessment or Strategic Conservation Plan; or species of mollusk, fish, amphibian, or reptile for which there is no open season in Arizona as identified in Commission Orders 40, 41, 42 or 43. Vulnerable species also include plant species with federal status (Listed Endangered or Listed Threatened under the ESA), state status (Highly Safeguarded or Salvage Restricted under the Arizona Native Plant Law) or G1 (Critically Imperiled) as assigned by NatureServe.

3. Declining Status

Reflects the extent to which population numbers or habitats were recently, are currently, or are anticipated to be in decline. The scores evaluate the degree of change that has been observed, estimated, inferred, or suspected in the area of interest over 10 years or three generations, whichever term is longer (up to a maximum of 100 years); see definition of “Global Short-Term Trend” (Master et al. 2012). The trend may be recent or current, and the trend may or may not be known to be continuing. Trends may be smooth, irregular, or sporadic. Fluctuations will not normally count as trends, but an observed change should not be considered as merely a fluctuation rather than a trend unless there is evidence for this. The period of time overlaps with the present, so that declines in the immediate past (whether considered ongoing or not), continuing trends, and trends projected to begin immediately are all included. Without evidence to the contrary, and if habitats remain largely intact, status was assumed to be stable.

4. Disjunct Status

Vulnerable species are represented by populations that have been geographically separated from the main population and, thus, vulnerable to population declines or local extirpation because of the distance from other major population centers (i.e., other geographic areas where large percentages of that species population occur naturally) and the low likelihood of immigration. An example is the montane vole that occurs only in the White Mountains in Arizona, yet the species is widespread from northern New Mexico throughout much of the Intermountain West. Vulnerability of species populations that are disjunct as a result of anthropogenic changes to the landscape are not included.  Peripheral populations (Arizona populations at the margins of the species distribution) are not considered vulnerable under this criterion.  

5. Demographic Status

This criterion considers birth and death rates of each species and known factors impacting those rates. Rates can be affected by intrinsic factors such as low genetic diversity, generation time, reproductive potential, and other life history characteristics. Extrinsic factors affecting rates include environmental change, illegal harvest, disturbance, and disease. California condors are an example of a species with high demographic concerns.

6. Concentration Status

Species that have a portion of their life history during which large numbers of individuals, representing a significant portion of the population, are concentrated in relatively small geographic areas, and thus are more vulnerable to local threats and catastrophic events. For example, birds that congregate at a few major migratory stopover sites, communal bat roosts or maternity sites, and breeding aggregations of some amphibians. 

7. Distribution Status

This criterion is meant to assess the percentage of a species’ reproducing population that occurs in Arizona. Because population data are difficult to compile, from an operational standpoint, scoring reflects the percentage of a species’ geographical distribution that occurs in Arizona. Species that score high have a significant proportion of their global or U.S. breeding range within Arizona, thus indicating Arizona has a high responsibility for maintaining viable populations in the state, even if the species is locally abundant (e.g., Abert’s towhee or Harris’s hawk).

Assigning SGCN Tiers

During this scoring process, the team sought support and input from species experts from partner organizations before finalizing the new SGCN list. Following this initial vulnerability assessment scoring, the resulting SGCN list was further refined into three tiers as follows:

Tier 1: Deemed vulnerable (scored a “1”) in at least one of the seven above categories AND matches at least one of the following:

• Federally listed as endangered or threatened under the ESA

• Recently removed from ESA and currently requires post-delisting monitoring

• Specifically covered under a signed conservation agreement CCA or a CCAA or a Conservation Strategy and Assessment or Strategic Conservation Plan

• Closed season species (i.e., no take permitted) as identified in Arizona Game and Fish Commission Orders 40, 41, 42 or 43

Tier 2: Deemed vulnerable (scored a “1”) in at least one of the seven categories described, but matched none of the additional criteria for Tier 1.

Tier 3: Species with “unknown status” in at least one of the seven above categories but don’t rise to a Tier 2. These species are those for which we are unable to assess status, and thus represent priority research and information needs. As more information becomes available, their tier status will be re-evaluated.

Table 1:  SGCN totals by taxonomic group and tier.

See Appendix D: Species of Greatest Conservation Need with Vulnerability Scores for the complete list of SGCN with associated tier ranking (includes indicators of status changes from the previous assessment in 2012).

The SGCN list is used to develop conservation strategies to aid in prioritization of projects and activities and to develop recommendations for land management activities and development projects that consider wildlife impacts. The SGCN list also plays a critical role in defining Conservation Opportunity Areas (COAs), a new element included in the AWCS that highlights specific areas on the landscape where conservation effort will be most beneficial for SGCN and other wildlife (see Chapter 4: Arizona’s Conservation Approach).