## Facts

- BLM considered a right-of-way over federal land in Nevada for the Silver State South industrial solar project.
- The project area lay outside designated desert tortoise critical habitat but within a corridor identified as important for desert tortoise population connectivity.
- After an initial proposal, the developer submitted a revised project with a smaller footprint, leaving a narrower corridor between the project and the Lucy Gray Mountains.
- BLM initiated formal ESA consultation with FWS regarding the revised project.
- FWS issued a Biological Opinion (BiOp) concluding the project was not likely to jeopardize the continued existence of the threatened desert tortoise and would not destroy or adversely modify designated critical habitat.
- The BiOp acknowledged uncertainty about long-term demographic or genetic effects from corridor narrowing and referenced a developer-funded monitoring study to track potential changes.
- Relying on the BiOp, BLM issued a Record of Decision granting the right-of-way.
- Defenders of Wildlife sued under the ESA and APA, alleging the BiOp was arbitrary and capricious and that BLM unlawfully relied on it; the district court granted summary judgment to defendants, and Defenders of Wildlife appealed.

## Issues

1. Whether FWS’s no-jeopardy conclusion was arbitrary and capricious in its treatment of corridor connectivity and scientific uncertainty.
2. Whether FWS unlawfully failed to find adverse modification of critical habitat by not treating diminished connectivity as adverse modification.
3. Whether the BiOp was unlawfully inconsistent with earlier agency statements about the corridor’s importance without adequate explanation.
4. Whether the BiOp’s reinitiation-of-consultation trigger complied with ESA regulations and was sufficiently definite.

## Decision

- The Ninth Circuit affirmed summary judgment for the federal defendants and intervenor-defendants.
- The court held the BiOp’s no-jeopardy determination was not arbitrary or capricious, notwithstanding acknowledged uncertainty about connectivity effects.
- The court held the no-adverse-modification conclusion was reasonable because the project did not alter designated critical habitat, and reduced connectivity alone did not constitute adverse modification of critical habitat as analyzed in the BiOp.
- The court held any differences from prior agency views were adequately explained by the revised project configuration and updated analysis.
- The court upheld the consultation reinitiation provisions as sufficiently clear and consistent with ESA requirements.

## Legal Principles

- Under the APA, courts defer to an agency’s scientific and technical judgments when the agency considers the record, uses the best available science required by the ESA, and provides a reasoned explanation.
- The ESA permits agency decisionmaking in the face of scientific uncertainty; absolute certainty is not required for a no-jeopardy determination.
- A BiOp is not invalid merely because it references monitoring or possible future actions, so long as the no-jeopardy conclusion does not depend on speculative or undefined future mitigation as a necessary premise.
- For adverse modification, the inquiry focuses on effects to designated critical habitat and its relevant features; impacts on population connectivity may be treated as species effects without necessarily constituting adverse modification absent alteration of designated critical habitat.
- Agencies may change conclusions from earlier assessments if they explain the change and ground it in the specifics of a revised proposal and the administrative record.

## Conclusion

The Ninth Circuit upheld FWS’s Biological Opinion and BLM’s right-of-way approval for the Silver State South solar project, concluding the agencies reasonably addressed connectivity concerns and uncertainty, did not rely on impermissibly speculative mitigation, and acted consistently with ESA procedures under deferential APA review.


Defenders of Wildlife v. Zinke, 856 F.3d 1248 (9th Cir. 2017)