Biological Opinions - Bureau of Reclamation

These are discussed in greater detail in the final critical habitat rule (77 FR 73740).
9.2 Analytical Approach and Role of Critical Habitat in LRS and SNS Recovery
This BiOp does not rely on the regulatory definition of “destruction or adverse modification” of
critical habitat at 50 CFR 402.02. Instead, we have relied upon the statutory provisions of the
ESA to complete the following analysis with respect to critical habitat.
In accordance with policy and regulation, the adverse modification analysis in this BiOp relies
on four components: (1) the status of critical habitat, which evaluates the range-wide condition
of designated critical habitat for the LRS and the SNS in terms of primary constituent elements
(PCEs), factors responsible for that condition, and the intended recovery function of the critical
habitat overall, as well as the intended recovery function in general of critical habitat units; (2)
the environmental baseline, which evaluates the condition of the critical habitat in the action
area, factors responsible for that condition, and the recovery role of the critical habitat in the
action area; (3) the effects of the action, which determines direct and indirect impacts of the
proposed Federal action and effects of any interrelated or interdependent activities on the PCEs
and how that will influence the recovery role of affected critical habitat units; and (4) cumulative
effects, which evaluates the effects of future non-Federal activities in the action area on the PCEs
and how that will influence the recovery role of affected critical habitat units.
For purposes of the adverse modification determination, the effects of the proposed Federal
action on LRS and SNS critical habitat are evaluated in the context of the range-wide condition
of the critical habitat, taking into account cumulative effects to determine if the critical habitat
range-wide would remain functional (or would retain the current ability for the PCEs to be
functionally established in areas of currently unsuitable but capable habitat) to serve its intended
recovery role for these two species.
The analysis in this BiOp places an emphasis on using the intended range-wide recovery function
of LRS and SNS critical habitat and the role of the action area relative to that intended function
as the context for evaluating the significance of the effects of the proposed Federal action, taken
together with cumulative effects, for purposes of making the destruction or adverse modification
determination.
An adverse modification analysis determines if the physical or biological features of critical
habitat would remain functional to serve the intended recovery role for the species as a result of
implementation of a proposed Federal action (77 FR 73740). The key factor related to the
adverse modification determination is whether, with implementation of the proposed Federal
action, the affected critical habitat would continue to serve its intended conservation role for the
species. Activities that may destroy or adversely modify critical habitat are those that alter the
physical or biological features to an extent that appreciably reduces the conservation value of
critical habitat for the LRS and the SNS (77 FR 73740). The role of critical habitat is to support
life-history needs of the species and provide for the conservation of the species.
Additionally, it is important to note that the hydrologic thresholds identified in the effects
analysis for the LRS and the SNS also apply to the critical habitat analysis below.
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