SUPPLEMENTARY INFORMATION:

Background

Under section 4(b)(3)(B) of the Act (16 U.S.C. 1533(b)(3)(B)), we are required to make a finding on whether or not a petitioned action is warranted within 12 months after receiving any petition that we have determined contains substantial scientific or commercial information indicating that the petitioned action may be warranted (“12-month finding”). We must make a finding that the petitioned action is: (1) not warranted; (2) warranted; or (3) warranted but precluded by other listing activity. We must publish a notification of these 12-month findings in the Federal Register .

Summary of Information Pertaining to the Five Factors

Section 4 of the Act (16 U.S.C. 1533) and the implementing regulations at part 424 of title 50 of the Code of Federal Regulations (50 CFR part 424) set forth procedures for adding species to, removing species from, or reclassifying species on the Lists of Endangered and Threatened Wildlife and Plants (Lists). The Act defines “species” as including any subspecies of fish or wildlife or plants, and any distinct population segment of any species of vertebrate fish or wildlife which interbreeds when mature. The Act defines an “endangered species” as a species that is in danger of extinction throughout all or a significant portion of its range (16 U.S.C. 1532(6)) and a “threatened species” as a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range (16 U.S.C. 1532(20)). Under section 4(a)(1) of the Act, the Secretary of the Interior (Secretary) may determine whether any species is an endangered species or a threatened species because of any of the following five factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

These factors represent broad categories of natural or human-caused actions or conditions that could have an effect on a species' continued existence. In evaluating these actions and conditions, we look for those that may have a negative effect on individuals of the species, as well as other actions or conditions that may ameliorate any negative effects or may have positive effects.

We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors). The term “threat” may encompass—either together or separately—the source of the action or condition or the action or condition itself. However, the mere identification of any threat(s) does not necessarily mean that the species meets the statutory definition of an “endangered species” or a “threatened species.” In determining whether a species meets either definition, we must evaluate all identified threats by considering the species' expected response and the effects of the threats—in light of those actions and conditions that will ameliorate the threats—on an individual, population, and species level. We evaluate each threat and its expected effects on the species, then analyze the cumulative effect of all of the threats on the species as a whole. We also consider the cumulative effect of the threats in light of those actions and conditions that will have positive effects on the species, such as any existing regulatory mechanisms or conservation efforts. The Secretary determines whether the species meets the definition of an “endangered ( printed page 36092) species” or a “threatened species” only after conducting this cumulative analysis and describing the expected effect on the species.

The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis, which is further described in the 2009 Memorandum Opinion on the foreseeable future from the Department of the Interior, Office of the Solicitor (M-37021, January 16, 2009; “M-Opinion,” available online at https://www.doi.gov/​sites/​doi.opengov.ibmcloud.com/​files/​uploads/​M-37021.pdf). The foreseeable future extends as far into the future as the U.S. Fish and Wildlife Service can make reasonably reliable predictions about the threats to the species and the species' responses to those threats. We need not identify the foreseeable future in terms of a specific period of time. We will describe the foreseeable future on a case-by-case basis, using the best scientific and commercial data available and taking into account considerations such as the species' life-history characteristics, threat projection timeframes, and environmental variability. In other words, the foreseeable future is the period of time over which we can make reasonably reliable predictions. “Reliable” does not mean “certain;” it means sufficient to provide a reasonable degree of confidence in the prediction, in light of the conservation purposes of the Act.

In conducting our evaluation of the five factors provided in section 4(a)(1) of the Act to determine whether the Sangre de Cristo peaclam or black-backed tanager meet the Act's definition of an “endangered species” or a “threatened species,” we considered and thoroughly evaluated the best scientific and commercial data available regarding the past, present, and future stressors and threats. We reviewed the petition, information available in our files, and other available published and unpublished information for the species. Our evaluation may include information from recognized experts; Federal, State, and Tribal governments; academic institutions; foreign governments; private entities; and other members of the public.

In accordance with the regulations at 50 CFR 424.14(h)(2)(i), this document announces the not-warranted findings on petitions to list the two species. We have also elected to include brief summaries of the analyses on which these findings are based. We provide the full analyses, including the reasons and data on which the findings are based, in the decisional files for the Sangre de Cristo peaclam and black-backed tanager. Below, we describe the documents containing these analyses.

The species assessment forms for the Sangre de Cristo peaclam and black-backed tanager each contain more detailed biological information, a thorough analysis of the listing factors, a list of literature cited, and an explanation of why we determined that these species do not meet the Act's definition of an “endangered species” or a “threatened species.” To inform our status review, we completed a species status assessment (SSA) report for the black-backed tanager. This SSA report contains a thorough review of the taxonomy, life history, ecology, current status, and projected future status for this species. No SSA was completed for the Sangre de Cristo peaclam. This supporting information can be found on the internet at https://www.regulations.gov under the appropriate docket number (see ADDRESSES , above).

Sangre de Cristo Peaclam

Previous Federal Actions

On June 25, 2007, we received a petition from Forest Guardians (now WildEarth Guardians) to list 475 species, including the Sangre de Cristo peaclam, as an endangered or threatened species under the Act. On December 16, 2009, we published a 90-day finding (74 FR 66866) that the petition presented substantial information indicating that listing may be warranted for the Sangre de Cristo peaclam. This document constitutes our 12-month finding on the June 25, 2007, petition to list the Sangre de Cristo peaclam under the Act.

Summary of Finding

The Sangre de Cristo peaclam is a small freshwater clam thought to occur exclusively in Middle Fork Lake, a cirque lake in the Sangre de Cristo Mountains, Taos County, New Mexico, at nearly 11,000 feet (ft) (3,353 meters (m)) elevation. The initial species' description claimed that the Sangre de Cristo peaclam is found in mud along emergent grasses in sheltered embayments along the edge and outlet of the lake and suggested the species may occur in other portions of the southern Rocky Mountains. However, surveys consisting of over 750 voucher samples from Middle Fork Lake alone, including surveys initiated by the New Mexico Department of Game and Fish in the mid-1990s, have failed to find any additional occurrences. The 1987 description notes that the Sangre de Cristo peaclam was locally abundant, a finding inconsistent with subsequent sampling efforts.

Sphaeriid clams can be problematic to distinguish morphologically due to a limited number of shared ancestral traits and high levels of intraspecific phenotypic variation. Therefore, recent research has focused on a genetic approach to potentially clarify the taxonomy of the Sangre de Cristo peaclam. Whole body samples were collected from 14 sites in New Mexico and west Texas, including Middle Fork Lake. Two independent genetic markers capable of accurately identifying a species' uniqueness were then used to evaluate the validity of the Sangre de Cristo peaclam as a distinct species.

The results showed that the genetic sequences from Middle Fork Lake were effectively identical to those of both described and undescribed species listed in GenBank, a publicly available genetic database. This means there were very few differences in the genetic markers between the Middle Fork Lake samples and species already described in the scientific literature ( e.g., Euglesa fallax,E. compressa, E. variabilis,E. casertana, E. walkeri,E. floresiana, E. subtruncata,Sphaerium lacustre, S. occidentale, and S. indicum). One genetic marker from Middle Fork Lake matched (99-100 percent identical) samples from San Gregorio and Pioneer Lakes, which are about 150 kilometers (km) (93.2 miles (mi)) and 10 km (6.2 mi) away, and matched exclusively with E. variabilis and E. casertana. Another genetic marker from Middle Fork Lake also matched (99-100 percent identical) samples from eight other locations in the region.

A phylogenetic analysis ( i.e., an evolutionary tree that models the relationships and common ancestors of a group of organisms based on genetic data) of a combination of both markers showed analogous results with multiple, well-supported clades (branches). The only monophyletic clade (a branch with a single species) is from Perch Lake, which was most closely related to an undescribed species and E. floresiana,E. casertana or E. subtruncata. The samples from Middle Fork Lake are found in two statistically supported clades, one of which also included individuals from San Gregorio Lake, and the other of which also included individuals from Pioneer Lake in northern New Mexico.

The results of the various genetic analyses strongly suggest that the Sangre de Cristo peaclam is not supported as a valid taxon. Instead, individuals that ( printed page 36093) had been previously identified as Sangre de Cristo peaclam are most likely a member of either the most widely distributed non-marine mollusk in the world, E. casertana, or E. variabilis, which occurs throughout North America.

In conclusion, genetic evidence strongly indicates that the Sangre de Cristo peaclam is not a valid taxon. Additionally, since the initial species description in 1987, hundreds of samples have been examined genetically or morphologically and have failed to identify any specimen from Middle Fork Lake that are clearly Sangre de Cristo peaclam despite claims that the species was locally abundant. Thus, we consider specimens previously identified as Sangre de Cristo peaclam to actually be a more widespread cosmopolitan species rather than a narrow endemic limited to Middle Fork Lake. The best scientific data available present clear evidence that the Sangre de Cristo peaclam is not a unique species.

Thus, after assessing the best available information, we find that the Sangre de Cristo peaclam is not supported as a valid taxon, but rather a member of a widely dispersed cosmopolitan species, likely to be E. casertana or E. variabilis. Therefore, the Sangre de Cristo peaclam is not warranted for listing because it is not a listable entity under the Act. A detailed discussion of the basis for these findings can be found in the Sangre de Cristo peaclam species assessment form and other supporting documents on https://www.regulations.gov under Docket No. FWS-R2-ES-2026-1453 (see ADDRESSES , above).

Black-Backed Tanager

Previous Federal Actions

On May 6, 1991, we received a petition from the International Council for Bird Preservation (now BirdLife International) to list 53 different bird species, including the black-backed tanager ( Stilpnia peruviana), as an endangered or threatened species under the Act. On December 16, 1991, we published a 90-day finding that the petition contained substantial information indicating that listing may be warranted for all species (56 FR 65207). On May 21, 2004, we published our resubmitted petition findings that listing the black-backed tanager was warranted but precluded by higher priority actions, and we added the entity to our list of candidate species (69 FR 29354). We subsequently published 11 candidate notices of review between 2007 and 2025 which continued to find that the species was warranted but precluded by higher priority actions (72 FR 20184, April 23, 2007; 73 FR 44062, July 29, 2008; 74 FR 40540, August 12, 2009; 76 FR 25150, May 3, 2011; 78 FR 24604, April 25, 2013; 81 FR 71457, October 17, 2016; 84 FR 54732, October 10, 2019; 86 FR 43470, August 9, 2021; 87 FR 26152, May 3, 2022; 88 FR 41560, June 27, 2023; 90 FR 48912, October 31, 2025). At the time of the petition, the black-backed tanager was classified as Tangara peruviana. However, the black-backed tanager was later placed in the genus Stilpnia, and we now treat Tangara peruviana as a synonym. This document constitutes our 12-month finding on the May 6, 1991, petition to list the black-backed tanager under the Act.

Summary of Finding

The black-backed tanager is endemic to the Atlantic Forest along the southeastern coast of Brazil, and while the extent of the species' historical range is not known, it is estimated to currently occupy 11 to 100 locations throughout an extant range that measures approximately 72,500 square kilometers (km² ) (28,000 square miles (mi² )).

The black-backed tanager mainly occupies coastal sandbank forests, restinga (coastal scrubland), and lowland forests (up to ~700 m (2,297 ft) in elevation), and its diet consists primarily of fruit, and to a smaller extent, invertebrates found in canopy vegetation. The species is also known to visit other habitat types when certain fruit-bearing plants are ripening ( e.g., secondary forest, edge habitat near pastures, gardens, and orchards).

We have carefully assessed the best scientific and commercial data available regarding the past, present, and future threats to the black-backed tanager, and we evaluated all relevant factors under the five listing factors, including any regulatory mechanisms and conservation measures addressing these threats. The primary threat affecting the black-backed tanager's biological status is habitat loss from deforestation and sea level rise.

The black-backed tanager is “not rare” within suitable habitat, but because the species breeds in coastal habitats, its viability is closely tied to the persistence of these habitats within its range. Protected areas overlap with 21.5 percent of the black-backed tanager's extant range, and 49.4 percent of the remaining restinga within that range. These protected areas maintain very low illegal deforestation rates (0.08-0.1 percent) and provide adequate legal protection to the black-backed tanager's remaining suitable habitat. However, small-scale illegal deforestation has caused the loss of 0.69 percent of the remaining restinga within the species' range since 2010. This equates to an annual loss of approximately 0.05 percent of restinga within the black-backed tanager's range, which if projected into the future, could result in an additional loss of 1.25 percent of restinga habitat over the next 25 years. However, because one of the main tree species that black-backed tanagers feed on (Brazilian peppertree, Schinus terebinthifolia) persists in disturbed environments, it is likely that the species' viability will not be significantly impacted by small-scale deforestation in the future. Furthermore, multiple ongoing restoration efforts are actively restoring degraded habitat within the black-backed tanager's range and contributing to improving the species' current condition. So, while small-scale illegal deforestation may continue to occur, the amount of deforested habitat is likely to be offset in the future by these ongoing restoration initiatives such that we expect the total amount of suitable habitat available for the species to likely be stable or increasing.

Because the black-backed tanager mainly occupies coastal habitats, both sea level rise and temperature increases resulting from climate change are projected to impact the species' viability in the future. Restingas are projected to be one of the more climactically stable habitat types in the Atlantic Forest biome and are projected to lose 7 percent of their area by 2070 due to temperature increases resulting from climate change. In addition, coastal Brazil is expected to experience a median range of sea level rise of 0.22-0.25 m by 2050, for shared socioeconomic pathway (SSP)2-4.5 and SSP5-8.5 respectively. Because restingas consist mostly of pioneer plants, they may be able to retreat further inland as sea levels rise. However, many restingas in highly developed areas will be unable to retreat further inland due to existing urban structures, removing the possibility that some restingas within the black-backed tanager's range adapt to sea level rise. Furthermore, it is unknown how restingas may tolerate increased flooding and saltwater intrusion, both of which may lead to additional habitat loss and degradation. The black-backed tanager is known to opportunistically feed on ripening fruits in more inland areas and has even established residency in some higher elevation areas. Therefore, while it is unknown exactly how restingas will adapt to ( printed page 36094) changing environmental conditions, the species has demonstrated the ability to persist in more inland habitats and is therefore likely capable of withstanding small-scale losses of coastal habitat. Considering the potential effects of additional small-scale habitat loss, the likely stability or net gain of suitable habitat via restoration efforts, and the species' ability to adapt to shifting environmental conditions, the black-backed tanager will likely have either stable or slightly reduced viability into the foreseeable future.

We also evaluated whether the black-backed tanager is endangered or threatened throughout a significant portion of its range. We did not find any portion of the black-backed tanager's range for which both (1) the portion is “significant;” and (2) the species is in danger of extinction in that portion, either now or likely to become so within the foreseeable future. Thus, after assessing the best available scientific and commercial data available, we conclude that the black-backed tanager is not in danger of extinction throughout a significant portion of its range, or likely to become so within the foreseeable future.

Based on the best scientific and commercial data available, we determine that the black-backed tanager does not meet the definition of an endangered species or a threatened species in accordance with sections 3(6) and 3(20) of the Act. Therefore, we find that listing the black-backed tanager is not warranted at this time. A detailed discussion of the basis for this finding can be found in the black-backed tanager species assessment form and other supporting documents on https://www.regulations.gov under Docket No. FWS-HQ-ES-2026-1454 (see ADDRESSES , above).

Peer Review

In accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270), and our August 22, 2016, memorandum updating and clarifying the role of peer review in listing actions under the Act, we solicited independent scientific reviews of the information contained in the black-backed tanager SSA report from three experts and received peer review from two independent peer reviewers. Results of this structured peer review process can be found at https://www.regulations.gov under Docket No. FWS-HQ-ES-2026-1454. We incorporated the results of this review, as appropriate, into the SSA report, which is the foundation for this finding. We did not solicit peer review for the Sangre de Cristo peaclam because there was no SSA drafted for the species.

New Information

We request that you submit any new information concerning the taxonomy of, biology of, ecology of, status of, or stressors to the Sangre de Cristo peaclam or black-backed tanager to the appropriate person, as specified under FOR FURTHER INFORMATION CONTACT , whenever it becomes available. New information will help us monitor these species and make appropriate decisions about their conservation and status. We encourage local agencies and stakeholders to continue cooperative monitoring and conservation efforts.

References

A complete list of the references used in these petition findings is available in the relevant species assessment form, which is available on the internet at https://www.regulations.gov in the appropriate docket (see ADDRESSES , above) and upon request from the appropriate person (see FOR FURTHER INFORMATION CONTACT , above).

Authority

The authority for this action is section 4 of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

91 FR 36090