ALTERNATIVE B – AGGRESSIVE ACTION

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Biological Environment

Vegetation and Fire Ecology

Potential for Impacts from Catastrophic Fire

Subalpine Forests.  Vegetation in this group shows no departure from the normal fire return interval (table 2.1).  This indicates that the stand structure and composition and fuel loads are within the natural range of variability.  Potential for catastrophic fire is low.  Since 1930, the largest fire in these forests was only 773 acres.  Because of the increased capability for managed wildland fires than under the No Action Alternative, under Alternative B the amount of subalpine forest burned could increase.  Thus, the effects of Alternative B on subalpine forests would be beneficial, short-term, and minor. 

Upper Montane Forests.  Vegetation in this group shows moderate to high departures from the median fire return intervals (table 2.1) and only about 25% of them are within one return interval of normal.  About 75% of the red fir forest and montane chaparral have moderate departures.  Western white pine/Jeffery pine forests show larger departures from normal—about 70% of them have missed four or more fires.  The structure and composition of these forests now includes higher densities of small, shade-tolerant species so that fuel loads are higher than the natural range.  Chaparral has been reduced in size and extent. 

Under natural conditions, large stand replacing fires occasionally burn these forests, however, existing vegetative conditions would cause larger and higher-intensity fires.  Under Alternative B, the focus on managed wildland fires could increase the area burned in upper montane forests.  It also might increase because of the 36% increase of upper montane forest in prescribed fire units compared with the No Action Alternative.  However, less than 20% of this group would be burned through prescribed fire so the potential for catastrophic fire would remain high.  In general, the potential to restore areas under this alternative would be greater than under Alternative A, thus a decrease in intensity from major to moderate.  The effects of Alternative B on upper montane forests would be adverse, long-term, and moderate. 

Lower Montane Forests.  Vegetation in this group shows moderate to high departures from the median fire return intervals (table 2.1).  About 50% of these forests are within two median fire return intervals of natural due to an active prescribed fire program.  At the same time, about 50% of these areas are three or more return intervals from normal and some have extremely high departures from the median fire return interval.  Of the ponderosa pine/bear clover forest, 36% has missed 17 median return intervals.  Fire exclusion has changed these forests from being relatively open, to forests with understories of dense thickets of shade-tolerant tree species at the higher elevations and dense shrub at lower elevations.  The structure and composition is considerably outside the natural range of variability.  Ponderosa pine/mixed conifer and ponderosa pine/bear clover are undergoing a vegetative type change to white fir/mixed conifer forest.  Fire exclusion has significantly increased fuel loads and the potential of catastrophic fire.  While large stand replacing fires have occurred historically, under current conditions fire would have much greater intensity and be larger in size and extent than under the natural fire regime.  Fire burning in these conditions would alter gap distribution and the vegetative mosaic as well. 

By maximizing managed wildland fire, the number of acres burned in lower montane forests could increase under Alternative B.  Additional treatment would come from placing 50% more of the lower montane forest into prescribed fire units, compared with the No Action Alternative.  The new prescribed fire units would include about 75% of all lower montane forests, and would significantly increase the number of acres that would be restored.  Therefore, the potential for catastrophic fire would remain high initially, but would be significantly reduced over time as prescribed burns and managed wildland fire brought these areas into the range of natural variability.  The potential to restore significantly greater amounts of forest would be greater than under Alternative A.  The effects of Alternative B on lower montane forests would be beneficial, long-term, and major. 

Meadows.  Vegetation in the dry montane meadows shows high departures from the mean fire return interval (table 2.1).  Almost 80% of the area has missed four or more fires.  Many meadows in Yosemite are severely encroached upon by conifers and have significant amounts of Kentucky bluegrass and other non-native, cool season grasses.  In Yosemite Valley, the hydrologic regime in meadows have been altered.  Fuel loads are higher than natural because of conifer encroachment and the lack of fires.  Fire exclusion has significantly increased the potential for catastrophic fires in surrounding forests.  Maximizing managed wildland fire in Alternative B would increase the number of acres burned in the park.  The new prescribed fire units would include about 50% of all meadows.  Compared with the Alternative A, there would be about a 60% increase in meadows put into prescribed fire units, which would increase the number of acres that would be restored.  Therefore, the potential for catastrophic fire would remain high initially, but would be reduced as the use of prescribed and managed wildland fire brought these areas into the natural range of variability.  The potential to restore larger areas under this alternative would be greater than under Alternative A.  Thus, the effect of Alternative B on meadows would be beneficial, long-term, and moderate.

Foothill Woodlands.  Vegetation in the foothill woodlands shows low to moderate departures from the mean fire return interval (table 2.1).  Most of the areas in this type were burned in several large wildland fires during the 1990s.  Cheatgrass and other non-native annual grasses have invaded much of the foothills woodlands.  High-severity or catastrophic fire are typical fire behaviors for this group, due to the establishment of non-native species.  Compared with the No Action Alternative, maximizing managed wildland fire in Alternative B could increase the acres burned while additional treatment would come from about a 25% increase in the amount of foothill woodlands included in prescribed fire units.  The new prescribed fire units would include more than 75% of all foothill woodlands and thus would increase the number of acres restored.  Based on the increased area of treatment, and potential restoration of native vegetation cover, the effect of Alternative B on foothill woodlands would be beneficial, long-term, and moderate. 

Fire Management Treatments

The Aggressive Action Alternative would focus on managed wildland and prescribed fire while allowing the full array of fuel reduction and site preparation techniques, mainly aggressive reduction techniques, in wildldand/urban interface areas and along road and utility corridors. 

Managed Wildland Fire

Subalpine Forests.  Ninety-nine percent of subalpine forest occurs within the Fire Use Unit.  Maximizing managed wildland fire in this alternative would increase the amount of subalpine forests.  However, because of the small amount of total acres that would burn in this group, the effects of Alternative B would be the same as under Alternative A—beneficial, long-term, and minor. 

Upper Montane Forests.  Ninety percent of upper montane forest would be in the Fire Use Unit.  This would be 5% less than in the Fire Use and Conditional Units under Alternative A.  It is expected that managed wildland fire would have a beneficial, long-term, and major effect in the areas that burn.  Maximizing managed wildland fire in this alternative would increase the acres burned when compared with Alternative A.  Due to the increase in area treated, the overall effect of Alternative B on managed wildland fire in upper montane forest would be beneficial, long-term, and moderate.

Lower Montane Forests.  About 35% of lower montane forests would be in the Fire Use Unit.  This would be 5% less than in the Fire Use and Conditional Units under Alternative A.  It would be expected that managed wildland fire would have a beneficial, long-term, major effect in the areas that burn.  Maximizing managed wildland fire in this alternative would increase the acreage burned compared to the existing program.  Compared to Alternative A, the overall effect of managed wildland fire on lower montane forest would be beneficial, long-term, and moderate, due to the increase in area treated. 

Meadows.  About 60% of dry montane meadows would be in the Fire Use Unit, the same as in Fire Use and Conditional Units under Alternative A.  Maximizing managed wildland fire in this alternative would increase the number of acres burned compared to Alternative A.  Overall, the effect of managed wildland fire on meadows in Alternative B would the same as under Alternative A—beneficial, long-term, and moderate.

Foothill Woodlands.  About one quarter of foothill woodlands would be in the Fire Use Unit, the same as is in Fire Use and Conditional Units under Alternative A.  Maximizing managed wildland fire in this alternative would increase the number of acres burned compared to Alternative A.  Overall, the effect of managed wildland fire in foothill woodlands under Alternative B would the same as under Alternative A—beneficial, long-term, and minor.

Re-ignition clause.  While the effects of re-ignition might differ slightly from one vegetation type to another, the general effects of and concerns for re-ignition are similar, thus, all vegetation groups will be analyzed together.  Re-igniting forests during the normal fire season would be expected to have the same effects on vegetation as managed wildland fire.  When re-ignition was done in the shoulder season (just before or just after the normal fire season, when fuels contain more moisture, temperatures are cooler, etc.), there would be the potential for adverse effects on vegetation although the overall effect of these burns would be expected to be beneficial.  The impacts of shoulder season burns are hard to quantify and need more research, but generally speaking, the effects would be the same as described for prescribed fire.  To mitigate effects, re-ignitions would be carried out within the target condition for season of burn (table 2.4); this would significantly reduce the potential for adverse effects.  The re-ignition clause would significantly increase the number of acres treated and would reduce the potential for catastrophic fires than under Alternative A.  The overall impact of re-ignitions on vegetation would be beneficial, long-term, and moderate to major.

Holding Action and Monitoring Effects (water and retardant drops, helispots, and spike camps).  The effects of holding actions and monitoring are expected to be similar for all vegetation types, so the vegetation types will be grouped for this analysis.  Due to the increased use of prescribed and managed wildland fire, it is expected that impacts from holding actions and monitoring would affect more areas than under Alternative A.  However, the overall effect of water and retardant drops on vegetation would remain the same—adverse, short-term, and minor.  The effects of helispots and spike camps on vegetation would also the same as under Alternative A—­­adverse, short-term, and negligible.

Prescribed Fire

Prescribed fire would typically be used in restoration of areas where the fire return interval is three or more fires out of cycle, or to maintain target conditions in areas within the Suppression Unit or along the margins of the Fire Use Unit.  The total acreage in prescribed fire units would be the same in all action alternatives, but under Alternative B, Aggressive Action, the largest number of acres would be burned annually.

Subalpine Forests.  Less than 1% of subalpine forests would be within prescribed fire units in Alternative B.  The effect of prescribed fire would be the same as under Alternative A—beneficial, short-term, and minor. 

Upper Montane Forests.  Less than 20% of upper montane forests would be in prescribed fire units in Alternative B— twice the acreage included in prescribed fire units under Alternative A.  The impact of prescribed fire in these forests would be the same as under Alternative A, but the larger area burned would decrease the potential for catastrophic fire, compared with Alternative A.  Overall, the impacts of prescribed fire on upper montane forests would be beneficial, long-term, and moderate.

Lower Montane Forests.  These forests would be a primary focus of the prescribed fire program.  About 75% of the park’s lower montane forest would be in prescribed fire units in Alternative B.  This would be twice the area in prescribed fire units in Alternative A.  The effect of prescribed fire in these forests would be the same as under Alternative A, but the greater number of acres treated would reduce the potential for catastrophic fire.  The increase in area burned would increase the benefit compared to Alternative A.  Overall, the effect of prescribed fire in lower montane forests, under Alternative B, would be beneficial, long-term, and major. 

Meadows.  Meadows have the shortest fire return intervals of all vegetation types described for the park.  About 50% of the park’s dry montane meadows would be in prescribed fire units under Alternative B.  This would represent a 60% increase in area to be treated, compared to Alternative A.  The effects of prescribed fire would be the same as under Alternative A, but the significant increase in area treated would restore more meadows than under Alternative A.  The potential to restore more area under this alternative would be greater than under Alternative A, thus the beneficial effect.  Overall, the effect of Alternative B would be beneficial, long-term, and major. 

Foothill Woodlands.  More than 75% of park’s foothill woodland would be in prescribed fire units under this alternative.  This is nearly four times more than under Alternative A.  The effects of fire would be the same as in the existing program for Alternative B, but overall, under Alternative B the benefits would increase, due to the amount of treatment and shorter time frame for restoration.  Effects would be beneficial, long-term, and major.

Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

The effects of holding actions and monitoring would be similar for all vegetation types, so they will be grouped for this analysis.  Due to the increase in treatment acreage for prescribed fire and managed wildland fire, it would be expected that site preparation work would be more wide spread than under Alternative A.  Given the increased amount of site preparation, mitigation measures would be used to the greatest extent possible.  Overall, the effect of site preparation on vegetation would be the same as under Alternative A—adverse, short-term, and minor. 

Fuel Reduction by Hand or Machine

Effects of Reducing or Removing Biomass from Sites

While the removal of cut trees and shrubs from treated sites can reduce the intensity of future fires, it can have other effects on ecosystems, such as a loss of stored nitrogen and other vital plant nutrients.  Table 4.9 presents a comparison of methods used to remove cut trees and shrubs and a qualitative analysis of the movement and availability of nitrogen and other nutrients. 

Table 4.9   Qualitative Effects Of Different Methods Of Tree And Shrub Removal In Relation To Nutrient Availability

a van Wagtendonk 1996.

b Graham and Associates 1999.

c Based on the assumption that piles would be burned from November through March in the year following treatment.

d Piles would be visible until the prescribed fire unit is broadcast burned within the following 5 years.

e Includes physical constraints, project cost and time, labor, and other factors. 

f Amount of fuel (expressed in tons per acre) available for combustion on the site after treatment.

In Table 4.9, nutrient cycling and return implies the movement and availability through decomposition of nitrogen and other vital plant nutrients.  It is an indicator of the amount of nutrients returned to soils in the project site following treatment.  Fire behavior denotes the expected fire behavior during a wildland or prescribed fire after mechanical fuel reduction.  Positive visual impacts indicate the stand appearance and aesthetic value as perceived by visitors after completion of the project.  This often is best described in historical accounts as “natural and park-like.” Feasibility would be evaluated for each project and include labor, physical barriers, and project time and costs.  All scenarios assume that a prescribed fire would take place in the unit within 5 years after the fuel treatment. 

Aggressive Reduction Techniques

            Mechanical Tree and Shrub Removal.  These activities would occur primarily around the wildland/urban interface and along road and utility corridors.  It would be used, in areas where both plant community structure has been altered by years of fire exclusion and communities and developed areas are at risk from catastrophic fire.  Less than 1% of the park, or 7,664 acres, lies within wildland/urban interface boundaries.  Approximately 1,500 acres would be treated each year.  These activities usually would be followed by prescribed fire (effects discussed above).  To restore plant community structure to within its natural range of variability, large machines (i.e.  feller-bunchers) would be used.  Only lower montane forest and meadows would be treated in large enough areas to have more than a local effect.  Less than 5% of lower montane forest and less than 20% of meadows would be targeted for this treatment in Alternative B. 

Effects of biomass removal would include the increased potential for trampling and burial of sensitive plants and communities (e.g. riparian areas), the appearance of cut stumps, and the loss of fuel ladders (see also table 4.9).  All of these impacts would be mitigated through project planning and coordination with resource management staff.  Surface and soil disturbance and compaction would also be caused by tracked vehicles and cutting, dragging, or crushing materials (depending on the treatment used).  This disturbance would provide potential sites for invasion of non-native species. 

Trees up to 31.5” dbh (diameter breast height) would be removed according to the structural target conditions for density and frequency, by vegetation type (see table 2.3).  Removal of trees would alter tree density and canopy cover in the immediate area.  However, canopy cover reduction should change fire behavior so that a high-intensity fire would be likely to be slowed and move on the ground rather than to move in the canopy (crown fire).  This treatment would not reduce the surface fuel load, which can be greater than half the total down and dead fuel load on a site.  In fact, it would actually increase the surface fuel load until the area was broadcast burned.  The intensity of fire would be temporarily greater due to this loading of fuels.  Overall, the adverse effects of biomass removal by mechanical means would be short-term and minor to moderate.  Long-term impacts would be beneficial and negligible to moderate, due to the lower potential for catastrophic fire in treated areas. 

            Conventional Tree and Shrub Removal.  Surface and soil disturbance and compaction would be associated with the use of wheeled and/or tracked vehicles and dragging materials.  This would provide potential sites for the invasion of non-native species.  Skidding would be used in some locations.  Mitigation would include running the equipment over snow or heavy brush and restricting equipment use to certain areas and paths.  Overall, the effect of skidding and grappling would be adverse, short- to long-term, and minor to moderate, depending on the intensity of treatment.

Passive Reduction and Lower Profile Techniques 

            Low-Impact Skidding.  This would include the use of draft animals and four wheel, all-terrain vehicles, in combination with fetching arches, to skid trees of approximately 10 to 20” dbh, to reduce locally heavy fuels.  In this alternative, the treatment would be used infrequently and only in areas with sensitive resources, as a substitute for other, heavier types of equipment.  This would cause limited compaction and scarification of the upper duff and topsoil layers.  Mitigation, when needed, could include skidding over snow, frozen soil or a bed of crushed materials, as with heavier equipment.  Adverse effects of use would be short-term and negligible to minor.  Because of its limited application in this alternative, the benefits of reducing fuels using low-impact methods would be short-term and minor. 

Hand Cutting.  Hand cutting would be used as needed in the Fire Use Unit and in some parts of the Suppression Unit and Special Management Areas.  Because this work is labor-intensive, accomplishments would likely remain at approximately 100 acres treated each year, as in Alternative A.  Amount of work would depend on how much was treated by other methods.  Overall, the effects of hand cutting on vegetation would be adverse, short-term, and minor—the same as under Alternative A. 

Pile Burning.  The effects of pile burning would be similar for all vegetation types, so vegetation types will be grouped for this analysis.  The impacts of pile burning would be the same as under Alternative A.  But, the increase in amount of treatment would affect a larger area.  The impacts of pile burning on vegetation would be adverse, short-term, and negligible to minor.

Chipping.  Chipping is one method for reducing the overall fuel loads in areas where hand thinning and/or biomass removal (by mechanical means) has occurred.  There are several options for reducing or removing biomass from sites.  The loss of nitrogen in the ecosystem is the greatest adverse effect of biomass removal.  According the Vegetation Management Plan (1997), chips should not be applied at depths greater than 3 inches.  Since that document was developed, further evidence has indicated that chips, due to their high cellulose content and the lack of moisture and nutrients in local soils to facilitate rapid breakdown, should be applied at depths no greater than 1 inch.  Chips can cause localized denudation by burying soils and seed banks, and robbing soils of available nutrients during the decomposition process.  Chips would be spread more thickly in some areas (e.g. road shoulders in the El Portal Administrative Site) to manage non-native species such as yellow star-thistle. 

Overall, the impacts of chipping on vegetation would depend on whether chips were broadcast or removed from the site.  If chips were broadcast, the impacts would be adverse, short-term, and negligible to minor, depending on the area treated.  If chips were removed, the impacts on vegetation would be adverse, short-term, and negligible.  Careful project planning and coordination with resource management staff would occur prior to project implementation, to select the appropriate treatment. 

Girdling.  Girdling would not be a part of this alternative.

Helibase Upgrades

Crane Flat: The removal of approximately 7,500 square feet of red fir forest and montane chaparral (primarily green manzanita) and periodic maintenance of trees in the glide path would result in a adverse, long-term, and minor impact to vegetation, due to potential invasion of the cleared site by non-native plant species, loss of topsoil (from wind and water erosion from lack of vegetation and subsequent decline in vigor and cover of existing vegetation.

El Portal: There would be no additional impact to vegetation because the helibase area is already paved or part of the road shoulder.

Wawona: There would be no additional impact to vegetation in Wawona Meadow because there would be no change in the current use of the area by helicopters.  There would be a long-term negligible, beneficial impact to the stand of trees adjacent to Wawona Meadow because the parking area would be better defined and parking amongst the trees would lessen.  There would be a long-term negligible, beneficial impact to the stand surrounding the driveway as tree removal and trimming would bring the stand closer to target conditions.

Cumulative Impacts

The past, present, and reasonably foreseeable projects effecting vegetation at Yosemite National Park would be the same as discussed under Alternative A.  The overall affect of past activities on the structure, composition, and fuel loads have been adverse, long-term, and major.  Past and reasonably foreseeable future projects would have a beneficial, long-term, and minor to moderate effect on vegetation.  These impacts, in combination with the impacts of Alternative B, would result in beneficial, long-term, and moderate cumulative impacts.

Conclusion

In aggregate the effect of Alternative B would be beneficial, long-term, and moderate to major, based upon a significant increase in the amount of area treated by prescribed fire and managed wildland fire.  The period of time required to restore park ecosystems (10 to 15 years) and reduce risks in and restore wildland/urban interface (5 years) would be within the normal range of fire return intervals for all but two vegetation types (ponderosa pine/bear clover forest and dry montane meadows).  This would significantly reduce the threat of large, high severity, catastrophic fire in all areas of the park, and would reduce the potential for vegetation type conversion.  This would be a beneficial effect, compared with Alternative A.  Large, high-severity fires would likely occur during the life of the plan, but the size and extent of the fires would be reduced compared to Alternative A.  The potential for catastrophic fire still exists, but the intent of the alternative is to reduce the risk, thus impairment would not result from the implementation of this alternative. 

The Mariposa Grove of Giant Sequoias is one of the resources specifically identified in the enabling legislation for Yosemite National Park.  If catastrophic fire were to eliminate or severely damage this grove, the impact would be impairment. 

Wetlands

Potential for Impacts from Catastrophic Fire

Effective implementation of this alternative would likely result in the greatest amount of change over the shortest time.  It would not eliminate the potential for catastrophic fire, but would significantly reduce the likelihood of high-intensity fires that are outside the range of tolerance for wetlands and associated species.  This reduction in the potential for large or unusually intense fires would result in beneficial, moderate to major, long-term impacts for park wetlands. 

Fire Management Treatments

Managed Wildland Fire

 Same as Alternative A—beneficial, long-term, and moderate.

Re-ignition clause.  Some managed wildland fires would be suppressed and later (within 3 years) re-ignited within the Fire Use Unit.  Wetlands in this unit, particularly meadow types, could be affected.  Given ecologically based criteria for re-ignition, adverse effects would be kept at a negligible level and moderate to major ecological benefits may be generated from fires burning at ecologically desirable times.

Holding Action and Monitoring Effects (water and retardant drops, helispot, and spike camps).  The effects of holding actions would be negligible in this alternative.  Ground-disturbing activities would be kept to a minimum in and around wetlands, but fires would be allowed to burn into and across wetlands where fires are managed for resource benefit.  Wetland habitats would be avoided to the greatest extent possible during holding actions and monitoring, and only a minimal amount of line would be constructed in wetland areas—in part because wetlands are often natural barriers.  Retardant would not be applied within 300’ of wetland areas and water drops would be kept to a minimum.  While meadows might be used as temporary helispots, this would only be done at dryer sites.  Impacts associated with holding actions on wetlands would be adverse, short-term, and negligible.

Prescribed Fire

The large number of acres treated annually and the distribution of treatments would result in specific impacts to wetlands.  In some areas, wetlands would be targeted for treatment, because of the need to control tree encroachment or change species composition.  Treatments would provide significant ecological benefit.  Although the total number of acres targeted would be well within the normal range of variability for fire regimes within the Yosemite landscape, the distribution of wetlands treated could potentially be un-naturally concentrated.  Fragmentation of wetlands and fires burning at compressed intervals rather than at natural fire return intervals could result in adverse, short-term and minor impacts.

Wildland/urban interface areas, such as El Portal and Yosemite West, would likely receive mechanical pretreatment, followed by prescribed fire.  Treatments would be implemented with the intention of avoiding impacts to wetlands (see hand cutting, below).  Specific impacts of treatments would differ little from the No Action Alternative, but the intensity would be expected to increase because of the increase in the number of acres treated.  Overall, the effects of prescribed fire on wetlands in Alternative B would be beneficial, long-term, and minor due to emphasis toward restoration of vegetative structure and function.  Short-term adverse impacts would be minimized through mitigation measures of planning and coordination with Resource Management staff.

Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

Site preparation for managed wildland fires and prescribed burns would include the use of wetlands as natural barriers and water sources for pumps where water is available.  When a wetland area is being used for a boundary, line construction and some snagging might occur in the adjacent uplands.  Minimum Impact Management Techniques would be used which can include flattening grasses and sedges, and creating wetlines from which to burn.  Burns would be allowed to back into and burn around wetlands and meadows or through them if the vegetation were dry enough to carry fire.  Wetland habitats would be avoided to the greatest extent possible during implementation of confinement and containment strategies.  If the objectives of a prescribed burn were to reduce conifer invasion of meadow, some established trees might be cut.  Since no actual disturbance to the wetland characteristics would be realized, the impacts would be beneficial, minor to moderate, and short-term.

Fuel Reduction by Hand or Machine

Aggressive Reduction Techniques.

            Mechanical Tree and Shrub Removal.  No biomass removal by mechanical means would occur in wetlands. 

Conventional Tree and Shrub Removal.  If for some reason fallen debris needed to be removed from meadows, attempts to move the material would be done when the water table had dropped and the surface was dry or in winter when snow would protect the meadow surface.  Methods used would mitigate the possibility of material digging into the soil surface and causing soil disturbance.  Impacts would be adverse, short-term, and negligible.

Passive Reduction and Lower Profile Techniques.

Hand Cutting.  In most areas of the park, no hand cutting would be conducted near wetlands.  Small conifers along the dry margins and edges of meadows in Yosemite Valley might be cut to reverse conifer encroachment.  At the interface of the large meadows some trees might be cut to restore the visibility of meadows from scenic viewpoints and forest trails.  These actions would occur in conjunction with restoration burning.  Exclusion of fire has allowed an unnaturally dense wall of conifers to grow at the interface between meadow and forest in some areas.  Meadow burning has been part of the program for many years and was commonly done by American Indians.  Cutting trees to open this “wall” of trees is desirable to the restoration of meadows.  Burning would kill additional trees and as areas are restored, burning would be the preferred treatment.  The impacts to wetlands associated with hand cutting would be beneficial, short-term, and minor to moderate.

Pile Burning.  Piles would be sited to avoid wetland areas wherever possible.  When fuel reduction work is done on the edge of a meadow wetland, piles might be put on the upland areas adjacent to the wetland, where they would then be burned.  Some movement of ash particles could subsequently wash into the wetland area, resulting in an increase of nutrient levels.  The impact of pile burning on wetlands would be beneficial, minor to moderate, and short-term.

Chipping.  No chipping would occur in wetlands.

Cumulative Impacts

Cumulative effects to wetland and aquatic resources discussed herein are based on analysis of additional wetlands activities within the Yosemite region and the potential effects of this alternative.  The past, present, and reasonably foreseeable projects that might affect local wetland patterns and large-scale or regional wetland patterns would be the same as evaluated in Alternative A.  These and park projects would result in both short-term and long-term adverse and beneficial impacts on wetlands in the areas.  Overall, impacts would be beneficial, long-term, and moderate effects for reasonably foreseeable future projects.  Considered in combination with the impacts of Alternative B cumulative impacts would be beneficial, moderate and long-term, due to the emphasis on restoration of vegetation structure and natural processes through the use of fire. 

Conclusion

Current threats to park wetlands are most strongly characterized by the continued, ongoing diversion of water from wetland areas and the potential for catastrophic fire.  Reduction of these threats results in clear benefit for a number of ecological communities, including wetlands.  The process of returning the park landscape to fuel conditions in which natural fire processes could take place would result in some minor or moderate, adverse impacts to wetlands.  The combined treatment acreages represent a significant portion of the landscape and avoiding wetlands would be potentially difficult or impossible.  Although the long-term impacts should result in moderate benefits to wetland resources, negligible to moderate adverse impacts may occur over the short-term.  Because of the aggressive program to reduce fuels and reduce the threat of catastrophic fire in Alternative B, impacts would be beneficial, moderate, and long-term.  The potential for catastrophic fire would still exist, but the intent of the alternative is to reduce the risk, thus there would be no impairment from the effects of this alternative. 

Wildlife

Potential for Impacts from Catastrophic Fire

Under Alternative B, catastrophic fire would have the same effects as described under Alternative A.  However, the risk of such events would be substantially reduced over the 10 to 15 years proposed for achieving target conditions in areas that exhibit high fuel loads.  In the Suppression Unit, areas that deviate three or more intervals would be targeted first for prescribed fire, with 2,520 to 12,872 acres burned per year.  The total acreage would depend upon acreage burned in the Fire Use Unit and the environmental conditions, but this alternative proposes ecosystem restoration within 10 to 15 years.  As compared to other alternatives, wildlife habitat would most rapidly be returned to a more natural condition.  Under Alternative B, rapid reduction of the threat of catastrophic fire and the rapid return of habitats to natural, target conditions would result in beneficial, long-term, major impacts to wildlife and their habitat.

Fire Management Treatments

In Yosemite and in surrounding forests, many mid- to low-elevation forests are overgrown with dense shrubs and young trees because of a history of fire exclusion.  Some areas are at high risk of unnatural high-intensity fire events.  These conditions affect the abundance and diversity of wildlife species directly by creating unfavorable habitat conditions for some species.  For example, dense understory growth may adversely affect habitat quality for California spotted owls and northern goshawks by limiting their access to prey (Weatherspoon et al.  1992, Maurer 2000, respectively).  The combination of wildland fire, prescribed burning, and fuel reduction proposed in this alternative would result in increased habitat and species diversity as gaps would be created in continuous forest and the edge along the forest/gap interface recovered with important understory plants that had been crowded out by shade tolerant species. 

Managed Wildland Fire

The goal to restore ecosystems in a 10 to 15 year period under Alternative B means that annual acreage treated with fire would increase, through an increase in managed wildland fire and re-ignition of suppressed fires in the Fire Use Unit.  Under the action alternatives, suppressed wildland fires could be re-ignited when conditions are favorable for a burn, up to 3 years after they were suppressed which would increase the number of acres burned on average.  Conditions for wildland fires would vary among years, resulting in years with few acres burning and years with many acres burning.  In years of more wildland fire activity, large areas of dense forests with fairly homogenous habitat would be changed to a mosaic of diverse habitats, thus the forest would support a larger array of wildlife. 

The aggressive action proposed in Alternative B would provide a valuable tool in restoring natural, fire-influenced wildlife habitat.  Because natural ignitions are somewhat random events, areas burned may not be those of highest management priority (i.e., high FRID areas).  Also, some areas are likely to burn at higher than natural intensities due to high levels of fuel accumulation, even when fire prescriptions and management are designed to minimize these events.  As a result, forest gaps, and consumption of large woody debris (which provides habitat diversity), would be greater than under the natural range of variation in some areas of a burn.  This could adversely affect species that favor dense, complex forest, such as hermit thrush, northern flying squirrel, and marten.  While these effects would be greater under Alternative B than under the other alternatives, such impacts must be weighed against the benefit of reduced risk of catastrophic fire, which would be much more damaging to wildlife and their habitat. 

Under Alternative B, impact of managed wildland fire on wildlife would be beneficial, long-term, and major, due to the resulting restoration of wildlife habitats and the relatively rapid rate of reducing the potential for catastrophic fire.  Mitigation: Use MIMT for fire management; identify sensitive wildlife resources to minimize adverse impacts.

Re-ignition.  Managed wildland fires might be re-started when conditions were favorable for their control.  This could be done during summer or could be in the spring or fall, which would be outside the period when most natural fires occur (summer when lightning strikes and dry fuels combine).  Igniting fires in the shoulder seasons would have an adverse effect on some species of wildlife that are adapted to the natural timing of fires.  For example, small mammals that hibernate in leaf litter could suffer higher mortality.  Overall, however, re-ignition would enhance the beneficial effects of wildland fire by increasing the amount of habitat returned to a more natural, fire-influenced structure and composition.

Prescribed Fire

The use of prescribed fire provides the greatest potential to restore wildlife habitat and reduce the threat of catastrophic fire in areas furthest from natural conditions.  Fire can also be planned to occur under conditions that maximize benefit to resources, including wildlife and habitat, and minimize fire-related impacts to sensitive wildlife resources (e.g., spotted owl nesting sites).

Under Alternative B, prescribed fire would be used to the greatest extent, especially in the Suppression Unit, which comprises some of the forests most severely altered from fire exclusion.  Much of this area is in mid-elevation mixed-conifer forest, which is among the most productive and diverse wildlife habitat in the park.  High levels of fuel loading in some areas would cause prescribed fires to burn at higher than natural intensities, even when fire prescriptions and management were designed to minimize this effect.  As a result, forest gaps and consumption of large woody debris (which provide habitat diversity) would be greater than typical within the natural range of variation for ecosystems of this type.  This could adversely affect species such as hermit thrush, northern flying squirrel, and marten.  Such impacts, however, must be weighed against the benefit of reducing the risk of catastrophic fire, which would cause a greater detrimental change in wildlife habitat. 

Also, prescribed fires would be started when conditions were favorable for their control.  This would often be in the spring or fall, which would be outside the dry season when most natural fires would occur.  This could have an adverse effect on some species of wildlife that are adapted to the natural timing of fires.  For example, small mammals that hibernate in leaf litter could suffer higher mortality. 

In habitats near developed areas, where protection of human-built structures and facilities is a concern, prescribed fire would be used to reduce fuel loads to the lower end of the natural variability.  If forests became more open (less understory vegetation) and contained less down wood, the effect on animal species that depend on these features, such as salamanders, small mammals, and ground-nesting birds, would be adverse.  However, overall a larger number of species would benefit from restoration of forests to a more natural condition. 

Conditions for prescribed fires would vary among years so that little burning occurs in some years, and, when conditions were favorable, many prescribed burns take place.  In years of high prescribed fire activity, large areas would likely be affected.  Habitat would be no longer suitable to species that favor dense forest structure, but would be more suitable to species that favor open forests and more diverse habitats.  Under Alternative B, impact to wildlife would be beneficial, long-term, and major due to the restoration of wildlife habitats and reduction in the potential for catastrophic fire.  Mitigation: Use MIMT for fire management, identify sensitive wildlife resources to minimize adverse impacts.  Where possible, limit fire size and/or provide burn intensity heterogeneity and maintain wildlife species diversity.

Holding Action and Monitoring Effects (water and retardant drops, helispots, and spike camps) and Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

Adverse effects from fire control actions, such as hand lines, spike camps, helispots, and water drops (described under Alternative A) would increase in under Alternative B because of the greater use of managed wildland and prescribed fire and the re-ignition clause.

            Water Drops.  The types of impacts associated with water drops would be the same as described under Alternative A, but the increased use of wildland fire under this alternative could increase the use of water drops.  Impacts to wildlife could therefore, be greater than under Alternative A, but adherence to mitigation measures would limit impacts.  Threat of disease transmission, spread of non-native species, and effects on declining amphibians from water drops would still result in minor, adverse, long-term impacts.  Mitigation: Avoid dipping from waters known to contain mountain yellow-legged frogs; avoid dipping from small bodies of water. 

            Fire Retardant.  The impacts of fire retardant (released by aircraft) would be the same as described under Alternative A, but the larger number of wildland fires under Alternative B could increase its use, but use of standard mitigation measures would limit adverse effects.  Impact of retardant drops on wildlife under Alternative B would be adverse, short-term, and minor.  Mitigation: Adhere to established protocols for retardant use; limit use in park.

            Helispot Construction.  The types of impacts associated with helispot construction would be the same as under Alternative A, but the greater use of wildland fire under Alternative B could result in a greater chance of impacts on wildlife, through habitat destruction and direct disturbance.  Impact under this alternative would be adverse, long-term, and negligible.  Mitigation: Limit helispot construction, place helispots away from sensitive resources, use natural clearings for helispots.

Spike Camps.  Under Alternative B, the types of impacts associated with the establishment and use of spike camps would be the same as under Alternative A.  The greater use of wildland fire could however, result in more spike camps to manage and monitor fires.  Mitigating impacts would result in negligible, adverse, short-term effects on wildlife.  Mitigation: place spike camps away from sensitive resources, maintain strict control over the availability of food to wildlife.

            Handline.  The greater use of wildland and prescribed fire in Alternative B would likely include reduction in the use of hand lines that would be necessary during suppression of catastrophic fires.  Impact of hand line construction under Alternative B would be adverse, short-term, and minor.  Mitigation: Use MIMT in hand line construction, identify sensitive wildlife resources to minimize adverse impacts, rehabilitate areas.

            Snagging.  Impacts from snagging under Alternative B would be the same type identified under Alternative A, but like hand line construction, snagging would likely increase under Alternative B, due to increased use of fire.  This would have a local, adverse effect on those species using the snags that were removed, such as some bat species and woodpeckers.  Prescribed fire, however, would likely generate additional snags that, over the long-term, would benefit these species.  In addition, the reduction in the threat of catastrophic fire from use of prescribed fire would provide benefit for a wide range of wildlife species.  Under Alternative B, impact on wildlife from snagging would be adverse, short-term, and minor, based upon the greater use, but the relatively small area that is likely to be affected along the periphery of fires.  Mitigation: Use MIMT, limit snag removal to those snags identified as a clear threat to human safety and fire line integrity, identify sensitive wildlife resources to minimize adverse impacts.

            Mop-up.  The impacts to wildlife from mop-up activities under Alternative B would be of the same type identified under Alternative A, but the greater use of prescribed fire under Alternative B would increase such impacts.  The small, dispersed areas that would be affected, however, would limit adverse effects.  Impact of mop-up under Alternative B would be adverse, short-term, and negligible.  Mitigation: Use MIMT and identify sensitive wildlife resources to minimize adverse impacts. 

Fuel Reduction by Hand or Machine

Aggressive Reduction Techniques. 

Under Alternative B, annual treatment of forests in wildland/urban interface areas and along road and utility corridors would be greatest of all alternatives, primarily through the use of heavy machinery to cut and remove trees and reduce biomass.  To provide protection for developed areas, prescriptions for wildland/urban interface areas would thin forest structure to the lower end of the natural range of variability for tree density and fuel loading.  This would affect the species composition of wildlife in these areas.  For example, species that depend upon habitat complexity on the forest floor and in the understory, such as marten and some small mammals, would be adversely affected.  The conditions achieved, however, would benefit a larger number of species by restoring a forest structure that is within the range of natural variability for fire-influenced habitat.

            Mechanical Tree and Shrub Removal.  Heavy equipment would be used where critical fuel conditions demand immediate, efficient action, and where natural resources can acceptably withstand the impacts associated with this method.  The use of tracked vehicles in forest habitat would create ground disturbance that would affect animals that live in the forest litter, such as salamanders, reptiles, and small mammals.  Removal of trees and snags to reduce forest density would affect animals using these habitat features, such as bats and nesting birds.  This is especially true for snags, which would be valuable to a wide range of species.  Also, adjacent habitat would remain unaffected and thus be a source for recolonization.  If debris were piled for later burning, some mortality of animals that take up residence in piles, such as reptiles and small mammals, would occur, although most of these animals would likely flee.  The noise of heavy machinery would cause some short-term disturbance of wildlife in treatment sites and in adjacent areas.

Biomass removal by feller-bunchers would result in minor, beneficial, long-term impact to wildlife due to the rapid return of forest structure to a more natural, open condition near developed areas, although these areas would be relatively small on a landscape scale, and some adverse, short-term impacts would occur from use of heavy machinery.  Mitigation: avoid use of machinery in wet areas, identify and avoid impact to sensitive wildlife resources in treatment areas, and allow snags to stand where possible.

Conventional Tree and Shrub Removal.  Under Alternative B, rubber tired or tracked log loaders and grapplers would be used to remove hand-thinned trees and naturally downed trees and fuels.  It has the potential for damage through ground disturbance that would affect animals such as salamanders and small mammals.  Grappling and skidding would also result in the removal of large logs which provide habitat and structural diversity on the forest floor, with possible adverse effects on wildlife that use these features, such as marten, shrews, and dark-eyed juncos.  Use of heavy machinery would cause high noise levels that would disturb local wildlife.  Short-term impacts on wildlife from grappling and skidding under Alternative B are expected to be minor and adverse because of the small, disperse areas impacted.  However, in the long-term, restoration of park ecosystems would be beneficial to park wildlife. 

Passive Reduction and Lower Profile Techniques

Hand Cutting.  Same as Alternative A—beneficial, long-term, and minor.

Pile Burning.  In some cases, removed material would be piled and burned on-site, although some materials may be removed for later burning or sale.  With on-site burning, the impacts would be the same types as described under Alternative A, but would be somewhat greater since areas would be treated more quickly.  Some mortality of animals that would take up residence in the piles may occur, although such effects are still expected to be adverse, short-term, and negligible.  Mitigation: burn piles as soon as possible to minimize the number of animals living in them.

Chipping and Shredding.  Impacts to wildlife would be of the same type as under Alternative A, but the larger acreage treated under Alternative B would result in greater impacts.  Such impacts would be limited by use of standard practices such as thinly distributing chips over a site or removal of chips, both of which would limit suppression of plant growth and depletion of soil nutrients from decomposition.  Removal of chips, however, would also remove nutrients from the system.  The machinery used for chipping and shredding would be loud, which would disturb wildlife, such as nesting birds, in the short-term.  Impacts to wildlife from chipping and shredding would be negligible; adverse, and short-term.  Mitigation: follow established protocols for limiting the depth of chips distributed on a site.

Girdling.  Trees would be girdled to benefit wildlife species that need snags or standing dead trees as a habitat component.  Its use would be limited and would be combined with other techniques to reduce fuels to more natural levels.  Impact on wildlife, under Alternative B, would be beneficial, long-term, and minor.  Mitigation: Allow snags created by girdling to stand.

Peregrine Falcon

Same as Alternative A—adverse, short-term, and negligible.

Helibase Upgrades

Crane Flat: The removal of vegetation would have a long-term, negligible, adverse impact to wildlife due to additional fragmentation or loss of wildlife habitat.  The area represents a small area in proportion to the surrounding habitat that would remain unaffected.

El Portal: There would be a long-term, negligible, adverse impact to wildlife due to increased helicopter use in the Railroad Flat area, potentially disrupting wildlife behavior.  Disturbances would be infrequent and no habitat would be directly affected.

Wawona: There would be a long-term, negligible, beneficial impact to wildlife from clearing vegetation adjacent to Wawona Meadow, which would increase habitat quality by moving the stand toward structural targets.  The meadow is a wintering and staging area for great gray owls, and one of the last places where willow flycatchers are known to nest in the park.  Disturbances would be infrequent and no riparian habitat would be directly affected. 

Cumulative Impacts

The past, present, and reasonably foreseeable projects that would have the most direct relationship to Alternative B would be the same as listed under Alternative A.  The impacts of these actions, considered in combination with the impacts of Alternative B, would result in cumulative effects on park wildlife and habitat that would be beneficial, long-term, and moderate to major.  This is because projects with a beneficial impact would affect large areas of habitat in the central Sierra Nevada in ways that would compliment the beneficial effects of the Yosemite Fire Management Plan.  The Sierra Nevada Forest Plan Amendment would affect virtually all U.S. Forest Service land around the park through ecosystem-based management.  In comparison, projects with adverse impacts involve small areas and/or have minor effects over larger areas.

Conclusion

Alternative B would result in major, long-term, beneficial impacts on wildlife and habitat by rapidly restoring a more natural forest structure to areas of the park that have severely deviated from a natural fire regime.  The threat of catastrophic fire and its impacts on wildlife and habitat would be greatly and quickly reduced.  The potential for catastrophic fire would still exist, but the intent of the alternative is to reduce the risk.  Thus, there would be no impairment from the effects of this alternative. 

Special-Status Species – Plants

A total of four plant species known to occur in Yosemite National Park and the El Portal Administrative Site have been listed as rare by the state of California.  All are at lower elevations in the lower montane and foothills woodlands vegetation zones—mainly near El Portal.  Plants and their habitats are listed in table 3.5, see also discussion in Alternative A, Special-Status Species – Plants.

Potential for Impacts from Catastrophic Fire

Increased amounts of mechanical and hand cutting treatments in the El Portal Administrative Site would reduce the potential for catastrophic fire within El Portal and ecological restoration burning would reduce the potential for high-intensity fire beyond the bounds of the El Portal Administrative Site.  If a catastrophic fire were to occur, there would be adverse impacts from non-native species encroachment.  The probability of non-native species encroachment into sites burned by catastrophic fire would remain high, as in Alternative A, due to the impacts of high-intensity burning on soils and on understory and overstory vegetation.  However, under this alternative, the potential for catastrophic fire would be reduced, therefore the amount of non-native species encroachment would likely be less and direct impacts to special-status species plants would be reduced (compared to Alternative A).  Regarding catastrophic fire, under Alternative B impacts would be adverse, long-term, and negligible to minor.

Fire Management Treatments

Managed Wildland Fire

Under the Aggressive Action Alternative, all of the plant special-status species described in this document occur within the Suppression Unit, and only isolated populations of Yosemite onion grow in the Fire Use Unit.  During fire events, input from a Resource Advisor would continue to be used to minimize or eliminate impacts to these species (see Chapter 2, Mitigation under Actions Common to All Alternatives and Appendix 3).  Under Alternative B, the natural fire regime in areas inhabited by these species would quickly approach the natural range in variability over the landscape, and there would be a reduced potential for catastrophic fire events.  Therefore, impacts of managed wildland fire on special-status species under this alternative would be beneficial, long-term, and minor, due to return to natural fire return intervals with associated benefits to ecosystem function.

Re-ignition clause.  Re-ignition effects on special-status plants would only apply to isolated populations of Yosemite onion within the Fire Use Unit.  This species would neither benefit nor be adversely affected by re-ignition due to its isolated locations on sparsely vegetated outcrops.  Actions during re-ignition procedures would adhere to mitigation measures and avoid these populations or habitats (see Chapter 2, Mitigations under Actions Common to All Alternatives).

Holding Action and Monitoring Effects (water and retardant drops, helispots, and spike camps).  Special-status plant species are in areas that would be only minimally affected by the proposed actions in Alternative B.  These actions would have effects similar to Alternative A, despite increased burning and associated activities.  Mitigations would be as described in Alternative A.  Impacts of these actions taken in conjunction with mitigation measures would be adverse, short-term, and negligible.

Prescribed Fire

Effects would be similar to those described under Alternative A, however, in Alternative B potential effects to special-status species through prescribed burning would increase with the creation of a larger defensible perimeter around developed areas.  This is especially true in the El Portal area because many of these plants grow there.  Species would be potentially affected by burning in the shoulder seasons and the probability of non-native species encroachment into sites burned out of season would remain high, as in Alternative A.  Appropriate mitigation measures would be developed by the park Vegetation Ecologist and Fire Ecologist.  Mitigation measures common to all alternatives (Chapter 2) discusses the common practices for dealing with these situations.  Park vegetation personnel may recommend that some areas not be burned.  Impacts would be adverse, long-term, and minor to moderate.

Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

With the mitigations mentioned in Alternative A, impacts would be similar—adverse, short-term, and negligible to minor.

Fuel Reduction by Hand or Machine

Aggressive Reduction Techniques.  These techniques would be unlikely to occur in areas inhabited by special-status species. Mitigations to avoid special-status plant species would be employed therefore there would be no effect.

Passive Reduction and Lower Profile Techniques

            Low-Impact Skidding.   Low-impact skidding would not be done in areas inhabited by special-status plant species therefore there would be no effect.

Hand Cutting.  Hand cutting might affect special-status plant species only within the El Portal Administrative Site.  Mitigations (as described in Alternative A) would be used to limit impacts.  Yosemite onion and Congdon’s lewisia would not be affected by these activities, due to the location of populations.  Both Tompkin’s sedge and Congdon’s woolly-sunflower would be potentially affected by increased activities in wildland/urban interface areas, because of greater amounts of ground disturbance (through foot traffic, dragging cut materials, etc.) and subsequent changes in species composition if non-native species were to become established within the rare plant populations.  The impact of hand cutting, if mitigated to the extent possible, would be adverse, long-term, and minor.

Pile burning.  Pile burning would increase under Alternative B.  Increased activity near populations of Tompkin’s sedge and Congdon’s woolly-sunflower would increase the potential to harm these species.  Yosemite onion and Congdon’s lewisia would be unaffected by these activities due to the location of populations.  The expanded area of intensively managed vegetation surrounding El Portal would increase levels of disturbance in sites that currently receive no management attention.  Efforts would continue to be made to avoid individual plants and populations, by identifying their locations during planning.  Piles would be placed in areas that would be unlikely to support these species.  Therefore, impacts of pile burning on plant special-status species would be minor, adverse, and potentially long-term, due to the larger area of disturbance and increased potential for spread and establishment of non-native plants.  Appropriate mitigations as described in Alternative A and Chapter 2 (Mitigation Measures) would be applied prior to execution of each project.

Chipping.  Similar to Alternative A, although amounts of activity would increase.  By using measures described in Alternative A (planning, avoidance, depth of chips), effects would be mitigated, thus, effects would be adverse, short-term, and negligible to minor.

Girdling.  This action would not occur in areas inhabited by special-status plant species, therefore, there would be no effect.

Helibase upgrades

There would be no impact to special-status species because these species do not occur in the project areas of Crane Flat, El Portal, or Wawona.

Cumulative Impacts

Projects generating cumulative impacts that may affect special-status plants would be the same as those identified in Alternative A.  Impacts of increased mechanical treatments within known and potential habitats for special-status plant species, as well as actions associated with implementation of the Yosemite Valley Plan in El Portal, would have increased impacts from non-native plant species introduction and alteration of native plant habitat.  Overall, these effects, in combination with the effects of Alternative B, would result in adverse, long-term, and minor cumulative impacts.

Conclusion

Implementation of Alternative B, with increased mechanical thinning and removal, increased management of fuels around developed areas and increased burning would have an overall minimal effect on these species, due to their relative isolation, sparsely vegetated habitats, and occurrence beyond areas that would be managed aggressively.  The effect of Alternative B would be adverse, long-term, and minor.  There would be no impairment of the park’s resources or values. 

Special-Status Species – Animals

Sierra Nevada Bighorn Sheep (Ovis canadensis sierrae) – Federal Endangered

Potential for Impacts from Catastrophic Fire

Catastrophic fire would be highly unlikely in bighorn sheep habitat.  Lightning strikes that do start fires would help open up the landscape, making it more suitable for bighorns.

Fire Management Treatments

Managed Wildland Fire

Although use of wildland fire would greatly increase under Alternative B, its application on bighorn habitat would be limited since these areas are well within the natural fire return interval.  Managed wildland fire would have a negligible, beneficial, long-term effect on bighorn sheep.

Prescribed Fire

Prescribed fire would be unlikely to occur in bighorn sheep habitat, thus would have a negligible, beneficial, long-term effect on bighorn sheep.

Holding Action and Monitoring Effects (water and retardant drops, helispots, and spike camps) and Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

The improbability of these actions happening in bighorn habitat, however, limit their expected impact to adverse, short-term, and negligible.

Fuel Reduction by Hand or Machine

Fuel reduction treatments would not occur in bighorn sheep habitat. 

Cumulative Impacts

The past, present, and reasonably foreseeable projects that could affect bighorn sheep would be the same as identified in Alternative A.  Cumulative impacts from these projects, in combination with the impacts of Alternative B, would remain beneficial, long-term, and negligible. 

Conclusion

The impact of Alternative B on Sierra Nevada bighorn sheep would be beneficial, long-term, and negligible based primarily on the continued, though rare, influence of fire on their habitat.

Valley Elderberry Longhorn Beetle (Desmocerus californicus dimorphus) – Federal Threatened

Distribution of the valley elderberry longhorn beetle in the area administered by Yosemite National Park is restricted to the El Portal Administrative Site.  The entire life cycle of the valley elderberry longhorn beetle is connected to the elderberry plant (Sambucus sp.).  Adverse effects on elderberry plants would therefore have an adverse effect on this beetle.  Current management of vegetation in El Portal follows U.S. Fish and Wildlife Service guidelines for protection of valley elderberry longhorn beetle and their host plants (USFWS 1999). 

Potential for Impacts from Catastrophic Fire

Under current conditions, accumulations of fuel in some areas of El Portal could lead to catastrophic fires that would have an adverse effect on valley elderberry longhorn beetle and their host plants.  Valley elderberry longhorn beetles and elderberry plants have existed under natural fire regimes for thousands of years, and chaparral and oak woodland communities where elderberry plants are found can burn at an extent and intensity that would cause high mortality of both beetle and host plant.  Actions taken under Alternative B, with a goal to treat all wildland/urban interface areas within 5 years, would greatly reduce the potential for catastrophic fire in El Portal.  Reduction of the threat of catastrophic fire would therefore, be beneficial, long-term, and moderate.

Fire Management Treatments

Managed Wildland Fire

El Portal Administrative Site, where valley elderberry longhorn beetle habitat occurs, is entirely within the Suppression Unit where wildland fires would be suppressed.

Prescribed Fire

Effects of prescribed fire would be similar to those described under Alternative A, but under Alternative B, prescribed fire use in El Portal would greatly increase in order to reach goals for wildland/urban interface areas within 5 years.  Its effect on valley elderberry longhorn beetles would be beneficial, long-term, and moderate by reducing the risk of catastrophic fire and because long-term benefit to elderberry plants through regeneration and reduced fuel loads would offset the unintentional, short-term impacts from beetle mortality.  Mitigation would include following USFWS guidelines for protection of valley elderberry longhorn beetle and their host plants (e.g. see Alternative A).

Holding Action and Monitoring Effects (water and retardant drops, helispots, and spike camps) and Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

With the greatly increased use of wildland and prescribed fires under Alternative B, the amount (but not the type) of impacts associated with management of these fires would likely increase, compared to Alternative A.  The following fire management actions would be unlikely to occur in valley elderberry longhorn beetle habitat and, therefore, would not affect the species: water and retardant drops, helispot construction, spike camps, and snagging. 

Impact on valley elderberry longhorn beetles of actions taken to manage prescribed fire under Alternative B would be adverse, short-term, and negligible, based upon their increased use, and therefore, greater chance of inadvertent effects.  Impacts would be limited by the application of mitigation measures in accordance with USFWS guidelines.

Fuel Reduction by Hand or Machine

Aggressive Reduction Techniques. 

            Mechanical Tree and Shrub Removal.  Heavy machinery, such as feller-bunchers would be used to achieve target conditions near developed areas.  This aggressive approach would result in a more open forest structure, with removal of some trees in the 15-30” dbh size range.  Compliance with U.S. Fish and Wildlife Service guidelines would minimize damage to elderberry plants, but some damage could occur.  However, there would be a reduction in the threat of catastrophic fire, which would in the long-term, help protect valley elderberry longhorn beetles and their host plants.  Impact of heavy machinery on valley elderberry longhorn beetles under Alternative B would be adverse, short-term, and minor.  In the planning area, host plants for the valley elderberry longhorn beetle only occur in El Portal area where minimal mechanical use would be anticipated. 

Conventional Tree and Shrub Removal.  After cutting, downed trees in some areas would be removed with skidders and grapplers.  This could have an adverse effect on valley elderberry longhorn beetles if elderberry plants were damaged or destroyed.  However, mapping of elderberry plants in the treatment areas and adherence to park protocols and U.S. Fish and Wildlife guidelines would avoid all but accidental damage.  Impact to valley elderberry longhorn beetles from skidding and grappling would be adverse, long-term, and negligible.

Passive Reduction and Lower Profile Techniques.

Hand Cutting.  Hand cutting to reduce fuels that threaten developed areas in El Portal would not likely adversely affect the valley elderberry longhorn beetle.  Standard mitigation requires the mapping of all elderberry plants in a treatment area.  All elderberry plants with stems greater than 1-inch diameter at ground level would be left.  This would protect the plants most likely to be inhabited by valley elderberry longhorn beetles.  Hand cutting could affect the recruitment of small plants into the larger, valley elderberry longhorn beetle-suitable size class.  The reduction in fuels by hand cutting, in combination with other treatments, would help reduce the threat of catastrophic fire, which would help protect valley elderberry longhorn beetles and their host plants.  Impact on valley elderberry longhorn beetles from hand cutting under Alternative B would be beneficial, long-term, and moderate.

Pile Burning.  Cut trees and brush would, in some cases, be piled and burned.  Impact to valley elderberry longhorn beetles and their host plants would occur if materials were piled and burned too closely to elderberry plants.  Park protocols and U.S. Fish and Wildlife guidelines would however, minimize the chance of damage.  Impact of pile burning on valley elderberry longhorn beetles under Alternative B would be adverse, short-term, and negligible. 

Chipping.  In some cases, when logistical, administrative, or ecological reasons made on-site burning unsuitable, cut materials would be chipped.  Effects would be the same as described in Alternative A—adverse, long-term, and negligible.

Girdling.  Girdling of trees would be used to reduce stand density in some areas.  This technique would eventually reduce fuel loading in some areas, but is unlikely to have much effect on valley elderberry longhorn beetles.  Impact of this technique on valley elderberry longhorn beetles would be beneficial, long-term, and negligible.

Cumulative Impacts

Specific past present and reasonably foreseeable projects that could adversely affect valley elderberry longhorn beetles near the El Portal Administrative Site would be the same as described under Alternative A.  Impacts to valley elderberry longhorn beetle from present and reasonably foreseeable actions would be beneficial, long-term, and minor.  Considered in combination with the effects of Alternative B, cumulative impacts to valley elderberry longhorn beetle would be beneficial, long-term, and minor.

Conclusion

Impact of Alternative B on valley elderberry longhorn beetles is expected to be beneficial, long-term, and minor due primarily to the reduction in the threat of catastrophic fire, through an intensive program of prescribed fire and thinning. 

California Red-Legged Frog (Rana aurora draytonii) - Federal Threatened

California red-legged frogs have nearly disappeared from the Sierra Nevada—only two populations are known to exist in the northern extent.  Recent surveys have found none in Yosemite (Knapp 2000) although habitat does exist.  Red-legged frog habitat was identified through wildlife habitat relationships analysis (Mayer and Laudenslayer 1988).

Potential for Impacts from Catastrophic Fire

Under the median fire return interval, approximately 92% of the high-quality habitat has missed more than four fires.  Most effects of catastrophic fire would be similar to under Alternative A, but actions under Alternative B would reduce fuel accumulations in 10 to 15 years and reduce the risk of catastrophic fire.  The effect on red-legged frog habitat from catastrophic fire would be reduced, compared to Alternative A.  Impacts would be beneficial, long-term, and negligible.  Mitigation: Identify potential red-legged frog habitat and focus fuel-reduction efforts on those areas.

Fire Management Treatments

Managed Wildland Fire

Managed wildland fire would be the primary method for managing high-quality red-legged frog habitat, because approximately 84% of it is in the Fire Use Unit.  Fuel loads and the risk of catastrophic fire would be reduced by allowing natural ignitions to burn under strict management protocols.  Because target conditions would be achieved in a 10 to 15 year period under Alternative B, the use of wildland fire would increase, through managing some lightning fires and re-igniting some suppressed fires.  Decisions about whether lightning fires would be managed or suppressed would be based upon the same decision elements as in Alternative A.  However, under Alternative B, suppressed wildland fires could be re-ignited when conditions were favorable for a burn (up to 3 years after they were suppressed).  Under the aggressive action proposed in Alternative B, this would be a valuable tool in restoring natural, fire-influenced wildlife habitat.  This would have a beneficial effect on red-legged frog habitat by quickly reducing the threat of catastrophic fire.

Re-ignited fires would be started when conditions were favorable for their control.  This would generally be in spring or fall, which is outside the period when most natural fires occur (summer when lightning strikes and dry fuels combine).  Burning in the shoulder seasons could have an adverse effect on frogs hibernating in riparian areas that would be burned.  However, no California red-legged frogs are known to exist in Yosemite.  Under Alternative B, managed wildland fire would have a minor, beneficial, long-term impact on California red-legged frog habitat by helping to restore the natural structure and fuel loading in riparian areas, and quickly reducing the threat of catastrophic fire. 

Prescribed Fire

Prescribed fires would be started in the shoulder seasons, when conditions were favorable for their control.  This would have an adverse effect on red-legged frogs hibernating in riparian areas when they were burned.  However, no red-legged frogs are known to exist in the park.  Most effects of prescribed fire would be similar to those under Alternative A, but the greater amount of burning would reduce the potential for catastrophic fire.  Impact to California red-legged frog habitat from prescribed burning under Alternative B would be beneficial, long-term, and minor, because of the relatively rapid treatment of habitats that have severely deviated from their natural fire return interval.  However, the area of high-quality red-legged frog habitat that would be affected would be relatively small. 

Holding Action and Monitoring Effects (water and retardant drops, helispots, and spike camps) and Site Preparation Associated with Managed Wildland Fire and Prescribed Fire (hand line, snagging, mop-up)

With the greatly increased use of prescribed and wildland fires under Alternative B, the effects from actions used to manage these fires would also increase.  Most effects would be similar to those described in Alternative A, but amount of effect would increase.  Mitigations would be the same as in Alternative A.  Impact of prescribed and wildland fire management actions on California red-legged frogs under Alternative B would be adverse, long-term, and minor, primarily from the threat of the bullfrog spread because of water drops.  This could be mitigated by prohibitions against dipping water from waters known to contain bullfrogs.

Fuel Reduction by Hand or Machine

Aggressive Reduction Techniques. 

            Mechanical Tree and Shrub Removal.  Under Alternative B, the use of feller-bunchers and other heavy machinery would be the primary method for achieving target conditions in wildland/urban interface and other areas associated with development and roads.  Such equipment would cause considerable ground disturbance, but would be unlikely to affect red-legged frog habitat, because it would not be used in wet environments.  If red-legged frogs were present, use of heavy equipment in riparian areas would have an adverse effect on frogs sheltering under shrubs and leaf litter.  However, no red-legged frogs are known to occur in the park so impact to red-legged frogs from mechanical thinning with heavy machinery would be beneficial, negligible, short-term, due to the reduction in unnaturally high levels of forest fuels.

Conventional Tree and Shrub Removal.  Under Alternative B, cut and down materials would be removed from some treatment sites using grappling and skidding equipment.  Disturbance of soil and forest litter would occur, which could affect red-legged frogs sheltering in riparian areas.  Impact, however, would be negligible, because no red-legged frogs are known to inhabit the park.  The habitat would benefit from the reduction in fuel loading facilitated by skidding and grappling.  Impact of grappling and skidding on red-legged frogs under Alternative B would be beneficial, long-term, and negligible.

Passive Reduction and Lower Profile Techniques.

Hand Cutting.  Site-specific effects would be similar to those und