_______________________________________________________________________________________

To: USDI Bureau of Land Management District Managers (Coos Bay, Eugene, Lakeview, Medford, Roseburg, Salem); USDA Forest Service Forest Supervisors within the Range of the Northern Spotted Owl in Oregon

Subject: Interim Guidance for Survey and Manage Component 2 Species: Red Tree Vole

INTRODUCTION:
This memorandum provides interim guidance to Oregon field units of the Forest Service and Bureau of Land Management to meet requirements in the Record of Decision (ROD) for the Northwest Forest Plan (NFP) relative to Component 2 surveys for the red tree vole [Arborimus longicaudus (Phenacomys longicaudus in the ROD)]. This guidance is to apply for a short term, estimated to be one-to-two years. The concept of this guidance was developed by an interagency team of field and research staff and approved by the Intermediate Management Group consisting of regional management representatives from the USDI Fish and Wildlife Service, USDA Forest Service, USDA Pacific Northwest Research Station, and USDI Bureau of Land Management (BLM). A copy of this guidance is being sent to the Regional Ecosystem Office (REO) for distribution to other agencies for informational purposes.

Viability ratings for this species were only slightly below acceptable when analyzed for the Final Supplemental Environmental Impact Statement (FSEIS) for the NFP, indicating that the risk to the species' viability is not great (see criteria in Appendix J-2 to the FSEIS). Early survey results suggest broader habitat usage than previously documented, and that site-specific surveys are not adding sufficiently to the scientific knowledge necessary to determine appropriate management for the species. Addition of this species to Component 4 (general regional surveys), while maintaining it as Component 2, will be recommended to the REO to augment species information on red tree vole habitat characteristics and populations. Because of the relatively low risk to species viability in the short term and the expected increase in data from regional surveys, it has been determined that field surveys are not needed for all project areas for the next couple of years and that the following, interim approach to survey and management of this species will be followed for the next one-to-two years.

Under this interim guidance, the landscape will be analyzed to determine red tree vole habitat availability through the year 2000, and to determine opportunities to maintain populations of red tree voles which can utilize that habitat to interbreed and disperse to Late-Successional Reserves or other suitable habitats. This will be facilitated by the use of existing geographic information system (GIS) themes containing particular forest characteristics to assess current and potential habitat. The results of this analysis will guide the need for surveys and for management. The need for survey is restricted to marginal habitat where potential source populations would be maintained. Management options provide flexibility for managers to maintain populations and to accomplish projects.

Attachment 1 provides background on the intent of the ROD and rationale for this guidance. Attachment 2 provides background on documented red tree vole biology and a survey protocol to be used in implementing the interim guidance contained in this memorandum. Attachment 3 presents answers to some of the anticipated questions about this guidance.

INTERIM GUIDANCE:
The following interim guidance will apply to land areas below 4,300 ft. (1,300 m.) on BLM Salem, Eugene, Roseburg, Coos Bay, and Medford Districts; below 4,300 ft. elevation on the Siuslaw, Siskiyou, Willamette, Umpqua, and Rogue River National Forests; and on the Mt. Hood National Forest, west of the Cascade Crest and below 3,300 ft. (1,000 m.). Although there is some indication that the Oregon red tree vole (Arborimus longicaudus) may also be found in northern California, this preliminary information needs further analysis before applying Component 2 Standards and Guidelines for this species to California. This interim guidance will apply in Oregon until further notice (approximately one-to-two years):

Screen 1 - Amount of Federal Land:
For the purpose of this memorandum, federal land is defined as lands administered by BLM and/or the Forest Service. Throughout the range of the Oregon red tree vole, identify the fifth-field watersheds in which projects are planned. In those watersheds where less than 10 percent of the land is under federal management and there is no direct dispersal connection to BLM or Forest Service lands in other watersheds, neither site-specific surveys nor management of red tree voles is required. If the watershed has greater than 10 percent federal lands, follow Screen 2.

Screen 2 - Habitat Condition Threshold:
This screen is to evaluate habitat conditions in those fifth-field watersheds with more than 10 percent federal lands. Fifth-field watersheds which have a sufficient threshold level of potential red tree vole habitat on federal lands are treated differently from those which do not have sufficient potential habitat on federal lands.

The threshold determining survey and management requirements for the red tree vole is:
a minimum of 40 percent of the federal land in the fifth-field watershed is forested and (a) has approximately 60 percent crown closure or greater, and (b) has an average conifer tree diameter at breast height (DBH) of approximately 10 inches or greater, and (c) this closure and diameter can be maintained through the end of the decade (year 2000).

This initial threshold analysis can be done by local offices in a relatively short period of time through the use of GIS. Agencies or offices may differ in the data recorded for parameters such as canopy closure (e.g., data may be captured as 50-70 percent closure) and diameter. For GIS analysis, use existing agency data which is as close to the screen parameters (60 percent closure; 10 inch DBH) as is possible. These parameters may be convertible to more readily usable measurements (such as stand age) for the analysis. When GIS data is not considered adequate to determine these features, consult other informational sources such as recent aerial photos. Factor projects proposed for the short and long term into GIS analysis to aid in projecting future red tree vole dispersal opportunities.

Surveys Where Lands Pass Screen 1:

Where conditions meet threshold: Where conditions meet the habitat threshold (potential habitat is sufficient for dispersal), no site-specific surveys are required.

Where conditions do not meet threshold: Where fifth-field watersheds do NOT meet the habitat threshold (i.e., potential habitat may not be sufficient for dispersal), surveys are required before ground-disturbing activities. Follow the survey method in Attachment 2. If populations are found in the project area, managers have the option of conducting additional surveys outside of the perimeter of the project area to find nearby (within approximately 1/4 mile) populations for supplemental protection. In such a situation, the entire 1/4 mile band around the project perimeter need not be surveyed if the additional populations found will likely provide reproduction and dispersal capability when habitat conditions become appropriate. The definition of a red tree vole population is "two or more active nest trees spaced no more than 100 m. (330 ft.) apart."

Management of Known or Found Populations: Since the red tree vole is not a Component 1 species, all known sites are not required to be protected. As described below, management varies depending on whether the habitat threshold is or is not met.

Where the habitat threshold is met or exceeded: Where fifth-field watersheds meet the habitat screen criteria (i.e., potential habitat is sufficient), no surveys are needed before ground-disturbing activities. However, within the project area, prior surveys may have located one or more known red tree vole populations. These populations should be evaluated to determine the appropriate management. The focus of this standard and guideline is to maintain dispersal capability and gene flow (Appendix J-2, pp. 473-475). Management of each known site is not critical in these potential habitats as there should be suitable opportunity for reproduction, dispersal, and genetic exchange. In conjunction with discussions with biologists, managers have the flexibility to make a determination regarding whether or not (and by which method) populations will be maintained to contribute to the viability of the species. They also have flexibility in determining how many, if any, populations need to be maintained considering population size, condition, dispersal opportunities, overall quality of dispersal habitat in the watershed, proximity of other populations, and other factors. Appendix J-2 (pp. 474-475) and this memorandum's Attachments 2 and 3 contain information about the species which can be factored into management considerations and decisions. When one or more populations are found within a project area and a determination has been made to maintain some or all of the populations in the area, it is recommended that managers consider options a. through c. below. They should also consider the retention of clusters of large green trees around the populations or the monitoring of red tree vole populations before and after actions are completed to assist in refining management direction.

a. Protect populations within the project area with an approximate 10-acre buffer; or

b. Where adjacent Riparian Reserves have a high proportion of Douglas-fir and other habitat characteristics meeting the threshold, adjust the boundaries to incorporate the population area; or

c. Conduct additional surveys outside of the perimeter of the project area to find nearby (i.e., within approximately 1/4 mile) populations (as defined above) for protection by an approximate 10-acre buffer. The approximate 1/4 mile band for supplemental survey would allow identification and protection of populations in the project vicinity to ensure existence of local, source populations for interbreeding and dispersal, thus addressing concerns about the red tree vole. This distance is based on the greatest distance documented for red tree vole movement from its natal tree, which is 1115 ft. or, roughly, 1/4 mile. Protection of these nearby populations, instead of those in a project area, would allow management flexibility in implementing actions while at the same time providing protection for populations in that vicinity.

Where the habitat threshold is not met: The purpose of managing for red tree vole populations in this "marginal habitat" is so that populations are not lost which could be the source for dispersal at a later time, when the habitat is appropriate and when the landscape loses its fragmented characteristics. If populations are found within the project area, then either the populations within the project area or those populations found near the project area (approximate 1/4 mile perimeter) must be protected. Protect such populations using management options a. through c. listed above.

PROTOCOL MODIFICATIONS:
The protocol was designed to ensure a high probability of finding populations of this species across its range. Follow the standard protocol as closely as possible. In some situations, there may be specific conditions at a provincial or local level which may warrant modification of the protocol. Permanent staff biologists should make the decision on any needed modifications to protocol implementation based on their professional judgment. Where there is any deviation from the protocol, biologists are requested to document the specific changes made and the rationale for those changes. In addition, the data sets collected using the modified protocol should be clearly identified. This information will assist in future protocol revisions and in interpreting survey results.

COMPONENT 4:
As part of this interim strategy, we will submit to the REO the documentation for adding the red tree vole to Component 4 under the guidance for changing species status found on p. C-6 of the ROD. The goal of this change is to allow the collection of key habitat and population information which will clarify assumptions regarding the current abundance, distribution, and habitat relationships of red tree voles within the various physiographic provinces, and to refine our description of what stand conditions are desirable in maintaining some resident vole populations within the Matrix lands.

This direction is applicable immediately. Please address any questions to Cheryl McCaffrey (BLM), telephone number: 503-952-6050, email: cmccaffr; or Randy Hickenbottom (Forest Service), telephone number: 503-326-3626, DG: R.Hickenbottom:R06C.

3 Attachments:
1 - Jeske/Biswell Issue Paper dtd 09/05/96 (3 pp)
2 - Biology & Interim Survey Protocol (17 pp)
3 - Answers to Expected Questions (2 pp)

BLM Distribution:
WO-230 (Room 204 LS) - 1
CA-056 (P. Roush) - 1
OR-930 - 1
REO (Knowles, McNair, Pietrzak, Watson) - 4

JESKE/BISWELL ISSUE PAPER ON THE RED TREE VOLE
09/05/96

Prepared by Paul Jeske and Brian Biswell from September 3, 1996, red tree vole subgroup meeting.

Issue: How shall Record of Decision (ROD) requirements for the red tree vole be met in the short term?

Background:
The red tree vole is discussed in conjunction with Component 2 of the Survey and Manage species (ROD, p. C-5). Text from the ROD implies some criteria which should shape how surveys and management for the red tree vole should occur. The implied criteria (in italics) and relevant text is shown below.

• Use a landscape basis to begin analysis: "For most species the survey would start at the watershed level . . . "
• Design surveys and management to be efficient: "Surveys should be designed for maximum efficiency, . . . "
• Adjust activities based on what is most critical: "Work to establish habitat requirements and survey protocols may be prioritized relative to the estimated threats to the species. . ."
• Cover the range in 1997: "Within the known or suspected ranges and within the habitat types or vegetation communities associated with the species, survey for . . . red tree voles . . . must precede the design of all ground disturbing activities that will be implemented in 1997 or later."
• Manage for the species where it is found: "Where surveys are completed, the information gathered from them should be used to establish managed sites for species."

To some degree, these statements can be contradictory when considered individually. The best approach for interpreting the ROD is to try to consider statements in relationship to each other and as part of the whole.

Evolution of Recommendations:
The red tree vole team has written several draft proposed survey protocols and management recommendations. They are summarized below, with the most recent and recommended version discussed last.

Draft one: This draft required site-specific surveys for all ground-disturbing activities in all watersheds. This option began with an analysis of sixth-field watersheds. Site-specific surveys were required in all areas; however, there was some allowance for varying the survey intensity. Initial reviewers identified the need to target specific landscapes and to improve efficiency. This draft was not forwarded to agency managers for approval.

Draft two: This draft focused site-specific survey efforts to "connectivity corridors" which were not specifically identified. A process was identified to identify the corridors. Review comments questioned the adequacy and basis of the corridor concept (did not consider the entire range) and the efficiency of site-specific surveys (still too many surveys required). This draft was not forwarded to agency managers for approval.

Recommended for management approval and agency implementation, Draft three:
The team recognized that there was minimal scientific value identified with site-specific surveys associated with projects, and that requiring those surveys could be very expensive and labor intensive. The team also realized that there was little information available to use as the basis for management decisions. The team was willing to adopt this recommendation as an interim measure while better scientific data was developed through regional surveys. They also recognized that there were additional risks associated with not requiring site-specific surveys in all areas. To mitigate that short-term risk, the team proposed using this concept only in the short term (estimated to be FYs 1997 and 1998). During that period, a regionally managed, scientifically reliable, on-the-ground, habitat survey and geographic information system (GIS) analysis should be conducted. This very important survey should provide additional information about vole population levels and habitat requirements. One reason behind the rationale for not requiring site-specific surveys is the expectation that population and habitat information will be available as a result of this effort. At the conclusion of this survey and analysis, the requirements for red tree voles could be re-examined. The team recommends that the red tree vole be added to Component 4 of the survey and manage species to ensure that these habitat parameters and management needs can be refined.

With those concerns in mind, the proposal should meet ROD requirements, be reasonable for field offices to implement, and should provide better information as the basis for future decisions. The proposal is described below:

This plan considers the entire range. All fifth-field watersheds are considered. Screen first by the amount of federal lands in the watershed. In those watersheds where there is less than 10 percent of the land in federal management and no direct dispersal connection to federal lands in other watersheds, do not conduct site-specific surveys.

This plan designs surveys and management to be efficient. The second screen is to evaluate habitat condition in fifth-field watersheds (with more than 10 percent federal ownership). Fifth-field watersheds which have a sufficient threshold level of potential red tree vole habitat on federal lands are treated differently from those which do not have sufficient potential habitat. The threshold level of habitat suggested by the team is for 40 percent of the forests on federal lands in the watershed to have 60 percent crown closure and trees with approx. 10 inches diameter at breast height (average of trees in the stand). If this threshold can be maintained through the end of the decade, then no site-specific surveys would be required. This initial threshold analysis can be done by local offices in a relatively short period of time through the use of GIS. Team members estimated that many watersheds would not have to be surveyed because of these first two screens. The entire range would have been considered on a landscape basis in a relatively efficient manner.

This plan adjusts work based on what is most critical. The team felt that where the threshold level of habitat can be maintained through the decade, the species habitat requirements are at least minimally met in the short term. There should be suitable opportunity for reproduction, dispersal, and genetic exchange. The need for site-specific surveys or management around known sites in these landscapes would not be as critical. Local managers would manage known populations to benefit the species within the context of other management needs. They should also consider recommended past habitat "protocols" for the species but would have the discretion to determine how to manage the known sites within these watersheds. There would be a more critical need for site-specific surveys and management of known sites in watersheds which do not meet the threshold habitats. In these watersheds, site-specific surveys should be conducted; and past protocols for managing known sites should be adhered to (until new standards are developed). In landscapes which may have marginal habitat, it is important to try to maintain existing populations while habitat improves over time. Populations in marginal habitats are important when there are future opportunities for providing for population recovery, growth, and dispersal.

BIOLOGY

AND

INTERIM SURVEY PROTOCOL

FOR THE

RED TREE VOLE

[Arborimus longicaudus (= Phenacomys longicaudus
of the Record of Decision of the Northwest Forest Plan)]

IN OREGON

Interim Version 1.0

September 1996

EXECUTIVE SUMMARY

Species: Arborimus longicaudus: Red tree vole.
( =Phenacomys longicaudus of the Record of Decision of the Northwest Forest Plan)

Taxonomic Group: Mammals.

ROD Components: 2

Other Management Status: None.

Range: Arborimus longicaudus is endemic to Oregon and possibly northern California. Its exact distribution is uncertain but this species is believed to be restricted to mesic forest communities west of the crest of the Cascade Mountains in Oregon. The extent of its range in southern Oregon and northern California is in question. Arborimus longicaudus is believed to be isolated geographically and genetically from its sibling species A. pomo by the Klamath Mountains. However, recent DNA evidence suggests that the range for A. longicaudus may extend into northern California (Murray, 1995).

Specific Habitat: Habitat requirements appear to be mesic forest communities dominated by Douglas-fir. The species is significantly more abundant in mature to late-successional forests (Corn and Bury, 1986; Aubry, et al., 1991). Its abundance in younger forests is generally very low.

Threats: The major threat to this species is the geographic isolation of populations.

Management Recommendations: Late-Successional Reserves (LSRs) are thought to provide for well-distributed populations of this species. The Survey and Manage recommendations were initiated to provide additional habitat connectivity between LSRs, beyond that provided by Riparian Reserves (RRs).

Information Needs: Studies are needed to better understand red tree vole basic ecology, including its habitat associations, dispersal capabilities, current distribution, and natural abundance. Further genetic research is needed to resolve where the geographic distributions of A. pomo and P. longicaudus separate and to determine if there is any ecological differences between the two species.

I. NATURAL HISTORY

The distribution, biology, and ecology of the red tree vole (Arborimus longicaudus) in Oregon is poorly known (Hayes, in press). It is thought that the species has a very limited dispersal capability, and poor connectivity of populations between Late-Successional Reserves designated by the Northwest Forest Plan is a concern (Final Supplemental Environmental Impact Statement (FSEIS), 1994). Riparian corridors will offer dispersal opportunity, but maintaining habitat characteristics across the landscape may be required to facilitate dispersal between LSRs and RRs (Thomas, et al., 1993; FSEIS, 1994).

There is only limited information on the biology and ecology of the red tree vole, which is the smallest and least studied of the arboreal rodents of the Douglas-fir forests in the Pacific Northwest (Carey, 1991). The following section summarizes what is known.

A. Taxonomic/Nomenclatural History

The red tree vole Arborimus longicaudus was originally described in 1890 from a specimen collected from Marshfield, Coos Co., Oregon, and placed in the genus Phenacomys. Johnson (1968) proposed elevation of the subgenus Arborimus to full generic rank, effectively separating the tree voles into the new genus. In 1991 Arborimus pomo was proposed as a separate species (Johnson and George) incorporating all California populations into A. pomo.

There is continuing disagreement among taxonomists as to the appropriate genus of the red tree voles. The red tree vole has been alternately grouped within Arborimus and Phenacomys. However, recent DNA evidence supports the use of Arborimus as the correct genus (J. Hayes, pers. comm.; M. Murray, 1995). This protocol will use Arborimus for the genus.

Due to the recent (i.e., 1991) splitting of the California populations of the red tree vole into a new species, Arborimus pomo, there are no new common names which differentiate the two species. This protocol was developed for, and will apply to, all populations in Oregon which will be referred to as the red tree vole (Arborimus longicaudus) throughout this document.

B. Geographic Range

The red tree vole (A. longicaudus) is an endemic species to Oregon (possibly northern California), whose geographic range overlaps approximately 50 percent of the northern spotted owl's range in Oregon. Tree voles are an arboreal rodent that spend most of their life in the canopy of primarily Douglas-fir trees. This species is restricted to mesic forest communities west of the crest of the Cascade Mountains in Oregon. The extent of its range in southern Oregon and northern California is uncertain. Arborimus longicaudus is believed to be isolated geographically and genetically from A. pomo by the Klamath Mountains. However, recent DNA evidence suggests that the range for A. longicaudus may extend into northern California (Murray, 1995). Figure 1 in the Appendix displays the geographic ranges of A. arborimus and A. pomo as used for the Forest Ecosystem Management Assessment Team (FEMAT) Report and FSEIS analyses. This species does not occur in Washington State.

C. Biology and Habitat Requirements

1. Biology

The red tree vole is a small microtine rodent. Females of the species tend to be slightly larger than males. Individual weight varies from about 25-50 g (.87-1.75 oz.) (Hayes, in press). Total length (body and tail) for males ranges from 15.8-17.6 cm (6.2-6.9 in.) and for females, from 17.0-18.7 cm (6.7-7.3 in.) (Hall, 1981). The tail, which is relatively long for a microtine, accounts for about 40 percent of the total length.

The color of the dorsal pelage ranges from rust to cinnamon with some hairs tipped with black. Ventral pelage is whitish (Hall, 1981). The well-haired tail is black to brown in color (Maser and Storm, 1970; Whitaker, 1988). Juveniles tend to be more brown in coloration with black tails (Maser and Storm, 1970). Melanistic individuals have been observed (Hayes, in press). See Photo 1 in the Appendix for a picture of a red tree vole.

Reproduction in this species is characterized by a long reproductive period, small litter size, and slow development of young (Carey, 1991). Red tree voles can breed throughout the year, but generally litters are produced from February through September (Carey, 1991). Litters range in size from one to four (Carey, 1991) but average two (Howell, 1926). Females can have several litters in a given year (B. Biswell, pers. comm.). Gestation is approximately 28 days but may extend to 48 days if the female is lactating in support of an earlier litter (Carey, 1991).

The young start to venture from the nest at about 4 weeks of age (Howell, 1926). Activities of immature red tree voles (once they leave the maternal nest) are unknown. Red tree voles feed primarily on Douglas-fir needles, though they will occasionally feed on grand fir, white fir, Sitka spruce, and western hemlock needles (Carey, 1991). Douglas-fir needles have resin ducts along each edge which the vole discards, eating the fleshy portions of the needles (Howell, 1926; Whitaker, 1988). The resin ducts are used for constructing nests (Howell, 1926) and are a definitive indicator of tree vole use of a nest structure. Water is obtained from dew, rain, or condensation on foliage (Carey, 1991).

The main predator on this species is probably the spotted owl, though other owl species, raccoons, marten, ringtail, and fishers prey upon them as well (Maser, et al., 1981; Whitaker, 1988).

2. Home Range/Dispersal

The species is nocturnal, and some individuals may spend the majority of their lives in the canopy, moving from tree to tree through the canopy (Carey, 1991). Though they are almost exclusively arboreal, some terrestrial activity does occur; and occasionally individuals have been captured on the ground (Corn and Bury, 1986; Raphael, 1988).

The individual home range size for this species is not well known. However, Biswell (1996) found individual adult red tree voles, radio-tracked for 35-106 days, used 2-7 (median=5) nest trees, having independent non-interconnecting canopies. The greatest straight-line distance between consecutively occupied nest trees was an overnight move of 75.8 m. (248.7 ft.). Mean distances moved between consecutive nest trees for males and females combined was 31.4 m. (SE=6.49) (112.8 ft). When moving to a new nest tree, adult voles re-occupied previously constructed nest structures at least 68 percent of the time. Thirty-six percent of 39 nest trees located via telemetry contained more than a single nest, and one tree contained 7 nest structures.

The greatest distance moved by a red tree vole was by a dispersing subadult male. Followed for 40 days, he was located in five different trees and reached a maximum straight-line distance from his natal nest tree of 340 m. (1115 ft.) (Biswell, 1996). While moving far greater distances than adults, subadults have extremely low survival rates. Telemetered red tree voles crossed small forest roads, small streams, or canopy gaps while traveling between nest trees.

3. Abundance

Maser (1966) investigated the demographic structure and population density of a red tree vole population in a 12 ha. (30 ac.) stand of 25-30 year old, second-growth Douglas-fir located along the valley margin of the Willamette Valley. Forty individuals were captured, for an average of 0.42 voles per ha. (1.03 voles/ac.). Of these 40 voles, 62.5 percent were nestlings; 30 percent, adults; and 7.5 percent, independent subadults. Of the 37 located nests, 43 percent were occupied with an average of 1.08 voles per nest.

There is no information available concerning the species' longevity or activity patterns.

4. Nests

Red tree voles build conspicuous nests predominately in Douglas-fir trees wherever there is a suitable foundation and readily accessible food supply (Benson and Borell, 1931; Maser,et al., 1981; Carey, 1991). The species is believed to exhibit sexual segregation except for the purposes of reproduction. Adult males and females rarely occupy the same nest at the same time (Whitaker, 1988). Nest heights can vary from 0.9-45.6 m. (6-150 ft.) above the ground (Whitaker, 1988), but are most common in the lower one-third of the canopy (Gillesberg and Carey, 1991). The numbers of nests decreases with tree height above the first foliage (Gillesberg and Carey, 1991).

Some nests are found on single large branches or whorls of branches, and some are against the bole. Nest sizes are variable, ranging from a ball of material a little larger than a fist to as large as 1 m. (3 ft.) in diameter and 0.6-1 m. (2-3 ft.) in depth (Howell, 1926). Nest construction varies with the size and limb structure of the tree supporting the nest.

It is generally on the larger branches of old-growth trees that large nests are constructed. Biswell (1996), working in the Oregon Coast Range, found that approximately 40 percent of the nests he located were on single large branches. Single branches supporting nests averaged greater than 10 cm. (4 in.) in diameter. In trees with very large branches, tree vole nests can be 3-5 m. (10-16 ft.) or more out from the bole of the tree. Photo 3 in the Appendix displays a nest situated against a bole with a surveyor inspecting it.

Nests are constructed of resin ducts, lichen, feces, urine, conifer needles, and small twigs (Maser, 1966; Carey, 1991). Gillesberg and Carey (1991) report 117 nests; nest fragments were composed of approximately 51 percent resin ducts, 19 percent lichen, 13 percent feces, 9 percent needles, and 9 percent fine twigs by volume. Often the nests are covered with moss or lichen (Carey, et al., 1991). Multiple generations of voles may use the same nest, continually enlarging it; and a large nest may have several chambers and tunnels (Howell, 1926).

From the ground, red tree vole nests generally appear as dark haphazard accumulations of twigs, needles, moss, and/or lichens on the topside of a branch or against a tree bole. Closer inspection will reveal the diagnostic Douglas-fir resin ducts and openings to a tunnel system within the nest ball. Individual resin ducts and clumps of resin ducts can often be found below suspected nests, thus confirming use by red tree voles. Photo 4 in the Appendix shows small branchlets cut for food, and an accumulation of discarded resin ducts formed into a nest

Young trees can sometimes support small nests, and the nests may encircle the entire bole (Maser, 1966). In smaller trees, the nest starts as a feeding site with an accumulation of discarded resin ducts, feces, and food refuse. Additional twigs and branchlets are carried to the feeding site and gradually collect. In the Appendix, Figure 2, adapted from Maser (1966), shows the gradual development of a nest until it encircles the entire bole of a small tree. Photo 2 shows a tree vole nest next to a tree bole.

Multiple branches, re-sprouting after an injury or at sites of mistletoe infection, provide sturdy, secure sites for red tree voles to build large nests. In such cases, the nest is built among and on top of the branch system. Escape tunnels from the nest will lead to lower branches as well as to the top of the nest.

Red tree voles will sometimes use, and add to, nests constructed by other species, or construct nests in tree cavities or broken-top trees (Maser, 1966; Carey, 1991; Gillesberg and Carey, 1991). The structure of cavity nests has not been well described.

5. Habitat

Red tree voles are most commonly found in Douglas-fir stands, though they are on occasion also found in grand fir, Sitka spruce, and western hemlock (Howell, 1926; Walker, 1930; Huff, et al., 1992). They have been found in all seral stages of Douglas-fir forests from closed sapling/pole stands to older stands (Corn and Bury, 1986; J. Hayes, pers. comm.; J. Mires, pers. comm.), but tend to be significantly more abundant in mature and old-growth stands (Corn and Bury, 1986; Aubry, et al., 1991; Gillesberg and Carey, 1991; Huff, et al., 1992). Individuals have been captured in clearcuts (Corn and Bury, 1986), young second-growth Douglas-fir stands, and old-growth (Corn and Bury, 1986, 1991; Gomez, 1993; Gillesburg and Carey, 1991). Capture rates were significantly higher in old-growth, Douglas-fir forests than in young (40-60 year old) or natural mature forests (Gomez, 1993; Corn and Bury, 1991). In a random sample of stands in the central Coast Range of Oregon, red tree vole nest tree densities averaged 5.7/ha. (2.29/ac.) (range 0.32-13.59/ha.) in 150-300 year old stands; and 0.40/ha. (0.16/ac.) (range 0-1.96/ha.) in 25-110 year old stands (Biswell, 1996).

Biswell (1996) found nest trees generally had independent, non-overlapping canopies requiring the voles to move on the ground between some nest trees. Old-growth habitat appears to provide optimum habitat for red tree voles because it functions as a climatic buffer and has a high water-holding capacity, which maximizes food availability and free water (Gillesberg and Carey, 1991).

Little is known about the number or size of Douglas-fir trees, or the stand structural characteristics required to sustain a local population of red tree voles. Also, the relationship between number of nests and number of individuals is largely unknown (Carey, et al., 1991). As the size of a tree and its branches increase, the amount of suitable habitat within that tree also increases, making it more likely that the tree will be used for nesting by red tree voles (Gillesberg and Carey, 1991). The large limbs of old-growth trees provide the structural support for large nests, as well as escape routes. However, vole populations are often patchily distributed in forests. It is not known why (Carey, et al., 1991). It is conceivable that what appears to be suitable habitat may not have any red tree vole populations.

There is no conclusive information available concerning the minimum size stand necessary to support a population of red tree voles. Factors such as the number of suitable nest trees, canopy closure, and past and present disturbances may be more important to the suitability of a stand than its acreage (Huff, et al., 1992).

D. Key Habitat Characteristics

This list serves as a summary of known key red tree vole habitat characteristics. For further discussion of habitat characteristics, refer to the literature cited section.

• Restricted to forests west of the crest of the Cascade Mountains in Oregon (may occur in northern California also).
• Inhabits primarily old-growth and mature Douglas-fir forests and sometimes can be found in sapling/pole, closed canopy forests and in trees or stands composed of grand fir, Sitka spruce, white fir, or western hemlock.
• Elevation ranges from sea level to 1,300 m. (4,300 ft.), or the elevational limits of Douglas-fir forests.
• Nest distribution tends to be patchy within forests, which may reflect habitat patchiness at some scale.
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II. CURRENT SPECIES SITUATION

A. Why Species is Listed under Survey and Manage Standards and Guidelines

Between the Draft and Final SEIS, additional analysis was conducted for some species associated with late-successional and old-growth forests within the range of the northern spotted owl (FSEIS, 1994). These species were analyzed using four different "screens," which are discussed in depth in the J-2 Appendix of the FSEIS (1994). The red tree vole in Oregon failed to pass the screens due to its affinity with old-growth forests, its limited dispersal capabilities, and the lack of information concerning its distribution, habitat requirements, the effects of forest fragmentation and thinning on its populations, and its limited dispersal capabilities in younger forests.

The FSEIS Species Analysis Team's Mammal Subgroup felt the red tree vole in Oregon was in a slightly different position than many of the species placed under Survey Strategy #1 in the Record of Decision (ROD) Survey and Manage species list. The red tree vole has a wider geographic distribution, and their populations are thought to be in less dire circumstances than species on the Survey Strategy #1 list.

Therefore, the FSEIS Mammal Subgroup felt there was not a need to immediately protect every known tree vole site. Rather, individual sites needed to be assessed as to their value in adding additional connectivity between LSRs. If a stand containing red tree voles was in the middle of a large Matrix block comprised principally of older forests, then the stand's value for connectivity would be lower. A stand containing tree voles, with almost no older forest or suitable habitat around it, might have a much higher value in maintaining connectivity between LSRs. Therefore, Drs. Raphael and Aubry (members of the FSEIS Mammal Subgroup) suggested that a watershed or landscape assessment of the distribution of potential vole habitat should be a precursor to on-the-ground survey options (K. Aubry, pers. comm.; M. Raphael, pers. comm.). Because some additional mitigation was deemed necessary, the red tree vole remained as a Survey and Manage Strategy 2 species.

B. Major Habitat and Viability Considerations

Late-Successional Reserves and RRs play a large role in the continued persistence of the species, the latter being the main vehicle or corridor to the LSRs. Currently, some LSRs and many riparian zones are not totally functional ecologically due to past management, which increases the need to try and reduce interim impacts to current population centers in the Matrix. Over the next 75 years or so, LSRs and RRs are expected to develop and fulfill their ecological potential. During this interim period, preventing the isolation of major portions of the regional meta population is the concern. Retaining some tree vole populations in the Matrix helps maintain connectivity between LSRs, which was the approach selected in the ROD to prevent possible isolation.

C. Legal Status/Threats to the Species

The red tree vole is not listed on the Forest Service Regional Forester's Sensitive Species List or on the Bureau of Land Management's Oregon/Washington Special Status Species List. The species is not listed under the Endangered Species Act, nor is it a candidate for federal listing at this time. However, there is concern because of our very limited knowledge about the species' distribution, its apparent low abundance in younger stands, its limited dispersal capabilities (Thomas, et al., 1993; FSEIS, 1994), and its affinity for late-successional forests (Aubry, et al., 1991). Fragmentation of forest habitat by project activities, including timber harvest, may be limiting the amount of suitable habitat available and the ability of individuals and genetic material to move between the patches of suitable habitat that remain.

D. Distribution Relative to Land Allocations

Based on data presented in the FEMAT Report, 35 percent of the red tree vole's range in Oregon occurs on federal ownerships. Approximately 40 percent of that federal land within the tree vole's geographic range is managed as LSRs.

III. MANAGEMENT

A. Management Goals for the Taxon

The overall goal for management of the red tree vole under the ROD is to provide for well-distributed, functionally interconnected populations of the species within the range of the northern spotted owl. These conditions are believed to be essential to the long-term survival of the species.

B. Management Recommendations

See Interim Guidance Memorandum.

IV. SURVEY PROTOCOL

A. Protocol Purpose and Objectives

The Species Analysis Team's Mammal Subgroup, which was responsible for analyzing the red tree vole and developing mitigation measures for the FSEIS (1994), was convinced that in the future federal lands in LSRs and other large reserves would likely provide for large, well-distributed populations of red tree voles, with the possible exception of the northern Coast Range of Oregon. The team assumed that in the long term the RRs would provide for substantial connectivity between the reserves but that this connectivity would be incomplete in many areas for a species with low dispersal ability such as the red tree vole. The Survey and Manage mitigation recommendations for this species were prescribed in order to address concerns that under the selected alternative, there might not be sufficient connectivity through the Matrix between LSRs and RRs to prevent genetic isolation of the populations in the reserves. Because of this concern, the red tree vole in Oregon was included as a Survey Strategy #2 Survey and Manage species. Consequently, a survey protocol was to be developed and surveys conducted prior to all ground-disturbing activities implemented in FY 1997 or later (FSEIS, 1994).

B. Protocol Scope and Application

The FEMAT Report, the FSEIS (Appendix J2), and the ROD acknowledge the limited information available on the distribution and abundance of the red tree vole within western Oregon and within the range of the northern spotted owl. The Species Analysis Team, assessing tree voles in Oregon, limited their assessments to the forest community types and conditions found within the published geographic range (see Appendix Figure 1, map) for the species. Based on the geographic distribution information and known habitat relationships, the Species Analysis Team made recommendations for the management of red tree vole populations in Oregon. Those recommendations were incorporated into the Survey and Manage standards and guidelines of the ROD. Since the completion of the FSEIS and the ROD, a few new tree vole populations have been identified by Bureau of Land Management (BLM) biologists and Oregon State University researchers.

Most new localities occur in typical red tree vole habitat and merely extend the species range slightly east and south of the vole's previously documented range. A smaller group of these new localities are substantially outside the historically documented range of the species. These new localities are in landscapes dominated by drier forest communities than typical for the historic range.

These new dry forest localities are limited to the eastern Klamath and southern Cascades physiographic provinces near Medford, Oregon. Within the Medford region, there is no currently available quantitative information regarding the red tree vole's full geographic distribution, habitat relationships, or the affect current management guidelines will have on tree vole populations. It is also possible that this species occurs in northern California, but taxonomic distinctness between A. longicaudus and A. pomo is questionable. While uncertainty exists in the known range and taxonomic status of the species, we will only apply the protocol and interim management guidelines in the BLM Districts and National Forests identified in the Interim Guidance Memorandum and listed immediately below in Section IV.B.1. Future surveys will assist in confirming where the species actually occurs.

In general, the protocols will be applied to forested stands where Douglas-fir is a significant component of the species composition of the stand, up to the elevational limit of Douglas-fir stands on federal forests, regardless of land allocation but outside of wilderness and other Congressionally-withdrawn areas.

1. Implementation Area for the Regional Protocol

The REGIONAL protocol will be applied to the following National Forests and BLM Districts in Oregon. National Forests and BLM Districts are to implement the red tree vole protocol on the entire forest/district except where noted:

a. National Forests:

Siuslaw N.F.
Mt. Hood N.F.: Apply to areas west of the Cascade Crest and below 3,300 ft. or the local elevational limit of Douglas-fir forests.
Siskiyou N.F.: Apply to areas below 4,300 ft.
Willamette N.F.: Entire forest below 4,300 ft.
Umpqua N.F.: Apply to areas below 4,300 ft.
Rogue River N.F.: All forest lands below 4,300 ft elevation.

b. Bureau of Land Management Districts:

Areas below 4,300 ft. on the following districts:
Salem District
Eugene District
Roseburg District
Coos Bay District
Medford District

C. Trigger for Protocol

See Interim Guidance Memorandum.

V. FIELD SURVEY METHODS

These general field methods will be applied whenever the interim guidance requires ground surveys for red tree vole populations. Because red tree vole populations tend to occur in low numbers and in a somewhat clumpy distribution, survey techniques need to cover a large percentage of the survey area to ensure detection of vole nests.

Line-transect methodology will be used for all general surveys. Unlike strip surveys, line-transect methods do not assume 100 percent detection but are based on a detection function approach. In earlier studies, the average detection distance of vole nests, under various stand conditions, was 15 m. on either side of the transect line.

The survey process should follow these general guidelines:

• Randomize the starting point of the first transect segment along the stand's edge and space any additional transect segments parallel to the first segment. Where possible, run the transects across any environmental gradients, such as downslope rather than across the slope.
• Using the pre-located starting point, follow a predetermined compass bearing through the stand (transect line) and visually search the tree canopy for likely structures on both sides of the transect line. A minimum of 90 m. (approximately 300 ft.) of transect line per acre should be searched. Assuming a transect detection width of approximately 15 m. (49 ft) on each side of the transect line, this length of survey will visually cover approximately 68 percent of an acre. To calculate an adequate total transect length for a stand, multiply 300 ft. times the approximate acreage of the stand. This length of transect should provide a good assessment of the presence or absence of vole populations within the stand. The total length of transect needed to survey a stand can be divided into varying length segments and distributed throughout the stand to accommodate stands of various shapes and sizes.
• While walking the transect center line, visually search the branches and near the bole of the live portion of all trees along the transect using binoculars or a spotting scope. When nests or likely accumulations of litter-fall are observed, search under the tree for possible nest fragments containing resin ducts.
• Mark all trees that have evidence of mammalian nest material or are questionable for further evaluation. Search the ground under suspected nest trees for resin ducts that may aid in determining red tree vole use of the nest.
• If the nest is far out on a limb or is otherwise inaccessible, search the nest with binoculars looking for cut branchlets and resin duct clumps, as well as searching the ground for clumps of resin ducts. Climbing of trees should be the last resort in identifying a nest structure. This may happen if no resin ducts are found on the ground, or nests are too high in the canopy to see resin ducts with binoculars. However, stands containing good populations of voles will have several/many trees containing nests which should provide searchers with multiple opportunities to positively identify nest material.
• Field units that actually do surveys should maintain hard copies of survey plans, field forms, and the maps and aerial photos used during the survey. At a minimum, the following information should be recorded: legal description, Universal Transverse Mercator (UTM) coordinates of nest sites, name of person(s) surveying, date, number of nests and nest trees found, habitat type, tree species, and topographic map and copies of aerial photos showing nest(s) location. Field units may want a small sample of nest material to be collected by field personnel to serve as verification of species occurrence and as training aids. However, do not cause excessive disturbance or harassment to the nest itself or its inhabitants.

Though not required, it is suggested that information be collected that may help further refine the protocol and increase our knowledge of red tree vole ecology. Such information includes stand composition, average crown density, tree diameters, estimated distance to water, slope percentage, aspect, and distance to nearest old forest.

A. Protocol Testing and Refinement

Field units should maintain their own computer databases and geographic information systems pending development of the Interagency Species Management System.

B. Training

The protocol is designed for field biologists who will be analyzing habitat suitability and supervising red tree vole surveys on federal land within the range of the northern spotted owl. "Field biologists" are defined as those individuals currently employed as professional biologists, biological technicians, or volunteers that are supervised by a professional biologist.

Professional judgment is involved in analyzing habitat, conducting surveys, and interpreting red tree vole survey results and habitat use. A knowledge of the biology and ecology of the species and area to be surveyed will be essential for a reliable survey. The following qualifications are provided as requirements for the personnel involved in supervision, surveying, and the identification and interpretation of survey results.

• The minimum requirements for the supervising biologist are:

-- Bachelor's degree in wildlife biology or related field and/or qualification as a GS-486-9/11 and
-- Thorough understanding of all aspects of this protocol.

• Field surveyors should be familiar with project layout in establishing transect, trained to identify and interpret by visual observation red tree vole nests and sign, and be able to differentiate red tree vole nests from the nests of other species. It is highly recommended that potential surveyors be trained by a red tree vole expert who is knowledgeable about red tree vole biology, sign, surveying for the species, and interpretation of survey results.

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ANSWERS TO EXPECTED QUESTIONS

Q. WHAT IS CONSIDERED A RED TREE VOLE POPULATION FOR THE INTERIM GUIDANCE?

A. A population is considered to be two or more active nest trees spaced no more than 100 m. (330 ft.) apart. This is a lower limit on the number of active nests in a population. Stands may have over 25 trees containing active nests; this would be considered one large population. Every little clump that a surveyor might think is a nest does not need protection. Old abandoned nests can remain in a tree for about two years, and red tree vole nests can be confused with Douglas squirrel and flying squirrel nests. A single active nest may warrant protection only under special circumstances, such as when there is only one nest in an area which did not pass the second screen.

Q. IF EIGHT POPULATIONS ARE FOUND WITHIN A SALE UNIT, DO THEY ALL NEED TO BE PROTECTED? IF NOT, HOW DOES ONE DETERMINE HOW MANY NEED PROTECTION?

A. If the question refers to eight clusters of three or four active "nest" trees each and they are within 100 m. (330 ft.), there really is only one large population. Whether or not you need to save all the nest trees depends on such considerations as: the evidence of activity in this population, whether your watershed did or did not meet the screens, whether there are many other populations known in the watershed, the opportunities for dispersal, the proximity of Late-Successional Reserves (LSRs) or riparian reserves, etc. In general, a population found close to an LSR surrounded by other populations has less value than a population using an island of habitat strategically located in a gap between LSRs. Managers and biologists designing a unit have more opportunity for flexibility where units have large populations.

Where a unit passes the threshold (i.e., over 40 percent federal land; over 60 percent canopy closure; trees averaging over 10 inches diameter at breast height), every population does not necessarily need protection. There is management flexibility in determining whether or not a population is needed for viability of the species. The thresholds were developed to include minimum habitat for dispersal. It is recommended that the fifth-field watershed be further evaluated. For example, if most of the watershed is at the low end of the parameters, thus at the marginally valuable end of the threshold, then it could be important to maintain some of those populations. On the other hand, if the watershed has high quality dispersal habitat, the populations in a planned timber sale could be less important to maintain, as there are likely other populations and dispersal may not be a problem. If the field unit can monitor populations and conditions before and after thinning actions, results of the monitoring could assist with future adaptive management opportunities relative to the impact of thinnings on dispersal, etc., while allowing a planned action to proceed.

Q. DOES ONE NEED TO FIND ANOTHER EIGHT POPULATIONS OUTSIDE THE UNIT IF THE ADDITIONAL SURVEY OF APPROXIMATELY 1/4 MILE OUTSIDE THE PROJECT AREA IS DONE AS DESCRIBED IN THE INTERIM GUIDANCE?

A. This does not necessarily need to be an equal trade but select populations which will maintain the ability to serve as a source for dispersal through the decade. The number and location of these "substitute" populations could depend on such factors as: distribution of other planned activities, the ability of nearby areas to grow into suitable or potential habitat, the likelihood of the population to need to disperse more widely (which could relate to the size of the population or condition of the habitat), and other factors.

Q. WHAT IF NESTS ARE FOUND BUT IT IS NOT KNOWN IF THEY ARE NESTS OF THE RED TREE VOLE OR OF ANOTHER SPECIES, OR IF THEY ARE ACTUALLY ACTIVE RED TREE VOLE NESTS? IS IT NECESSARY TO SEND UP A CLIMBER WITH THE SAFETY HAZARDS, COSTS, AND TIME ASSOCIATED WITH THIS?

A. Use field clues before climbing. Look for resin ducts on the ground under the nest; look for cut branchlets on top of the nest; or shake a small tree before thinking of climbing. Seek other biologists who have considerable experience with red tree vole detection and learn the field clues from them. We should avoid the risk to human life involved in climbing every tree and spending excessive amounts of money on these simple surveys. However, until the surveyors develop a good search image, the confirmation of some small number of nests might need to be done. This should be left up to the judgment of the manager with concern for safety first and only after other means of determining nest status have been exhausted. Under Forest Service guidance, only certified climbers are allowed to climb trees (R6/PNW guidelines).

Q. EXPLAIN THE RATIONALE FOR THE PART OF THE THRESHOLD WHERE CONDITIONS WOULD BE MAINTAINED THROUGH THE END OF THE DECADE (THE YEAR 2000).

A. The Red Tree Vole Subgroup viewed the interim guidance as lasting only a year or two, by which time some information should be available from the general, regional surveys and geographic information system modeling. This improved information will provide a more reliable basis for management guidelines, better informed decisions, and for the Bureau of Land Management's Resource Management Plan assessments which are scheduled to occur in FY 1999.