SNFPA Final Supplemental Environmental Impact Statement

January 2004

Chapter 4: Environmental Consequences

4.3. Species of the Sierra Nevada

4.3.4. Neotropical Migratory Birds

A number of the high priority land bird species occurring in the Sierra Nevada bioregion (see chapter 3) are Forest Service sensitive species and are monitored in detail. Other species are not directly monitored, except at breeding bird survey routes and Monitoring Avian Productivity and Survivorship (MAPS) monitoring sites. Several others are MIS and are monitored at varying levels. Management for neotropical migratory birds is generally accomplished by focusing on providing a diversity of habitat conditions at appropriate levels across landscapes. Both alternatives involve similar desired conditions for forest types across the Sierra Nevada and would be expected to have the same difference in effects on neotropical migratory birds.

Alternatives S1 and S2 are consistent with the interim MOU between the Forest Service and FWS. Although the MOU has expired, the guidance it provides remains pertinent and is not in conflict with the direction contained in either alternative.

Four avian conservation plans in various states of completion are pertinent to evaluating effects on neotropical migratory birds. Each conservation plan includes recommendations for habitat conservation. Direction for both alternatives is consistent with those recommendations. The avian conservation plan (identified in chapter 3) for the Sierra Nevada bioregion identified four priority habitats. Each of these priority habitats corresponds to a focus area of the SNFPA FEIS, which are also the focus areas of the SEIS. In particular, direction for management of hardwood ecosystem would be the same under Alternatives S1 and S2.

Amounts of proposed vegetation management are similar for both alternatives, with slightly more acreage being treated under Alternative S2. The direction for snags varies between the alternatives, with more flexibility for local adjustment in Alternative S2. This flexibility could benefit neotropical migratory birds, because the same snag retention goals apply as under Alternative S1, but snags may be distributed across treated areas in patterns that increase the likelihood that they would persist over time, particularly where maintenance prescribed burning is planned. Under Alternative S2, snags would generally be retained in clumps distributed irregularly across treated areas. Although the four largest snags may not be retained, retained snags are expected to be in the largest size class of snags in the area.

Under Alternative S1, small groups of trees larger than 1 acre in CWHR classes 5M, 5D, or 6 would be managed by generally limiting tree removal to trees ≤12" dbh. Alternative S2 does not include this requirement but does require limiting tree removal to smaller diameter trees, based upon other stand characteristics such as basal area and canopy cover. It also has the same 30" absolute diameter limit as Alternative S1. Because the objective for fuels treatments under both alternatives is to treat surface and ladder fuels through thinning small diameter trees, differences in changes to individual forest stands between the alternatives are difficult to predict. Under Alternative S2, the diameter limit for tree removal will likely be higher than 12" in some forest stands that meet the CWHR 5M, 5D or 6 criteria, but the extent of difference with Alternative S1 would vary locally and depend upon the individual forest stand. The variability of the treatment unit prescriptions based upon existing stand conditions should ensure that a heterogeneous condition develops across treated forest stands.

Because Executive Order 13186 includes a broad mandate to promote conservation of migratory birds, both Alternatives S1 and S2 can be considered to comply with that mandate because they focus attention on priority habitats in the Sierra Nevada bioregion, as identified in the riparian-bird, oak-woodland, and conifer-forest avian conservation plans. Management direction for both alternatives is consistent with the objective of promoting conservation of migratory birds.

The direction in the SEIS is programmatic and the effects of individual projects on neotropical migratory birds will be analyzed at the project level. Potential effects on neotropical migratory birds at the local scale include modification of habitat and disturbance/destruction of individuals from mechanical fuels treatments, hand treatments, prescribed burning, and herbicide use. More specifically, effects could involve

• mortality of young in the nest due to physical disruption or nest abandonment by the adults who are intolerant to disturbance;
• loss or adverse modification of nesting, roosting, or foraging habitat; or
• direct or indirect effects from use of herbicides.

Neotropical migratory birds are also threatened by

• long-term changes in habitat due to development in foothill habitats,
• forest vegetation changes due to climatic changes of disturbance regimes,
• forest vegetation changes due to management alteration of disturbance regimes,
• loss from wildfire,
• changes in vegetation from livestock grazing,
• human disturbance associated with land use and recreation, and
• changes to stand structure from outbreaks of insects and diseases.

Many of these species are dependent on habitats beyond the national forests for a substantial portion of their lives, and management of national forests can at most only contribute to their conservation. Under Alternatives S1 and S2, the long-term habitat effects from large, high intensity wildfires would be reduced. These fires destroy habitat locally and increase habitat fragmentation across the bioregion. This reduction in large, high intensity wildfires would tend to increase stability of old forests and patches with old forest characteristics. Some neotropical migratory bird species utilize early successional habitats that develop following wildfires. Although these habitats will form at a diminishing rate, large areas of early successional habitat will nonetheless be generated in the near term. The objective of the fuels and vegetation strategy of both alternatives is to move the Sierra Nevada towards a condition where wildfires continue to create early successional habitats but at smaller patch scales and in a more heterogeneous pattern across the bioregion, which should improve the distribution of this habitat type.

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