Recovery Plan for the

Point ArenaMountain Beaver

Aplodontia rufa nigra (Rafinesque)
POINT ARENA

MOUNTAIN BEAVER

Aplodontia ru/a nigra (Rafinesque)

RECOVERY PLAN

Prepared by’

Dale T. Steele

and

Laurie Litman

for

Region I

U.S. Fish and Wildlife Service

Portland, Oregon

Approved:

Reg 1 D e .S. Fish and Wildlife Service

Date:
Disclaimer

Recovery plans delineate reasonable actions which are believed to be required to

recover and,’or protect listed species. Plans are published by the U.S. Fish and

Wildlife Service, sometimes prepared with the assistance of recovery teams,

contractors. State agencies, and others. Objectives will be attained and any

necessary funds made available subject to budgetary and other constraints

affecting the parties involved, as xvell as the need to address other priorities.

Costs indicated for task implementation and/or time for achievement of recovery

are only estimates and subject to change. Recovery plans do not necessarily

represent the views nor the official positions or approval of any individuals or

agencies involved in the plan formulation. other than the U.S. Fish and Wildlife

Service. They represent the official position ofthc U.S. Fish and Wildlife Service

wily after they have been signed by the Regional Director or Director as

approved. Approved recovery plans are subject to modification as dictated by

new findings, changes in species status. and the completion of recovery tasks.

Literature Citation should read as follows:

U.S. Fish and Wildlife Service. 1998. Point Arena Mountain Beaver (Aplodontia

ru/a nigra (Rafinesque)) Recovery Plan. Region 1, Portland, OR. 71 pp.

Additional copies may be purchased from:

Fish and Wildlife Reference Service

5430 Grosvenor Lane, Suite 110

Bethesda, Maryland 20814

301/492-3421 or 1-800-582-3421

The fee for the Plan varies depending on the number of pages of the Plan.
Acknowlcdgmcnts

The following individuals contributed significant information/assistance during

recovery plan preparation:

Dan Campbell

Jim Dines

Gary Fellers

Kim Fiffs

Sarah Flowers

Gordon Gould

Rickye Heffner

Mike Horton

Kevin Joe

Caryla Larson

Alan Levine

Darlene McGriff

Richard Meredith

Phil Northen

Renee Pasquinelli

Bert Pfeiffer

Ron Schlorff

Brad Valentine

Alison Willy

Ted Wooster

Special acknowledgement for the pioneering Aplodontia rufa nigra research by C.

Camp and E. Pfeiffer.

The cover drawing is used courtesy of the California Wildlife Habitat

Relationships Program, California Department of Fish and Game, Wildlife

Management Division from: D.C. Zeiner, W.F. Laudenslayer, Jr., K.E. Mayer,

and M. White, eds. 1990. California’s Wildlife, Vol. III, Mammals. California

Statewide Wildlife Habitat Relationships System. State ofCalifornia, The

Resources Agency, Department of Fish and Game, Sacramento, California.

11
Executive Summary

Current Species Status: The Point Arena mountain beaver (4plodontia rufa

nigra,) is a federally listed endangered subspecies. This subspecies of mountain

beaver is only known from a small area of coastal Mendocino County, California,

where 26 apparently separate populations have been found, with an estimated 200

to 500 animals total. Potential threats to the habitat ofthe species include

elimination or degradation from land development, grazing, timber harvest, and

invasion by alien plant species. Direct threats to the subspecies may include

predation by household pets and feral animals, poisoning, genetic isolation and

genetic drift, and human caused disturbance. Basic biological data are lacking to

determine the level ofvulnerability ofthe mountain beaver to each ofthese

factors.

Habitat Requirements and Limiting Factors: A. r. nigra requires a cool moist

environment. It lives in underground burrow systems under dense stands of

perennial vegetation where soil conditions allow for easy excavation.

Recovery Objective: The ultimate objective ofthis plan is to delist the Point

Arena mountain beaver, however, criteria for downlisting to threatened are also

established.

Recovery Criteria: The species will be considered for downlisting when:

1. At least 16 populations are protected from human-caused

disturbance in perpetuity. Each population shall contain at least 20

hectares (49 acres) of suitable habitat of which at least 10 hectares

(25 acres) are occupied habitat.

2. These populations shall have a mean density of at least 4 Point

Arena mountain beavers per hectare (1.6 per acre) of occupied

habitat, unless new data show that a lower density is healthy and

stable.

3. All 16 populations are stable (i.e., no more than a 25 percent

change in estimated population size from highest to lowest value)

or increasing for a period ofat least 10 years (following attainment

111
of criterion #1), as documented through establishment and

implementation ofa scientifically acceptable population

monitoring program.

4. The amount of additional habitat needed for population

interconnectivity, travel, and dispersal habitat has been determined.

5. Sufficient information is available to permit adaptive management,

and any management actions necessary to ensure the continued

success of these populations (in criterion #1) have been fully

implemented.

The species

1.

will be considered for delisting when:

Thirty populations are protected from disturbance in perpetuity.

Each population shall contain at least 20 hectares (49 acres) of

suitable habitat ofwhich at least 10 hectares (25 acres) are

occupied habitat.

2. These populations shall have a mean density of at least 4 Point

Arena mountain beavers per hectare (1.6 per acre) of occupied

habitat, unless new data show that a lower density is healthy and

stable.

3. All 30 populations are stable (i.e., no more than a 25 percent

change in estimated population size from highest to lowest value)

or increasing for a period ofat least 15 years (following attainment

of criterion #1), as documented through establishment and

implementation ofa scientifically acceptable population

monitoring program.

4. Additional habitat needed for population interconnectivity, travel,

and dispersal habitat has been protected and is being managed

appropriately.

5. Adaptive management prescriptions have been determined and

implemented for all populations.

Actions Needed:

1. Protect known populations.

2. Protect suitable habitat, buffers, and corridors.

3. Develop management plans and guidelines.

iv
4. Gather biological and ecological data necessary for conservation

of the subspecies.

zi. Determine feasibility of, and need for, relocation.

6. Monitor existing populations and survey for new ones.

7. Establish an outreach program.

Estimated Cost of Recovery: $1 ,047.000±.The total cost ofthis recovery effort

could be higher than this figure. The costs for several tasks needed for recovery

have vet to be determined.

Date ofRecovery: Downlisting could be initiated in 2015 and delisting by 2025.

V
Table of Contents

I. Introduction . 1

A. Description 1

B. Geographical Distribution 2

C. Habitat

D. Life History/Biology/Ecology 12

Burrows 12

Population Density 14

Nest 15

Burrow Commumtv 15

Cleanliness 16

Foraging 1 7

Activity 1 8

Thermoregulation 19

Osmoregulation 20

Behavior 20

Senses 21

Demographics __

Fragility 24

Pest Control 25

F. Reasons for Listing and Threats to Survival .. 26

F. Conservation Measures 31

II. Recovery 34

A. Objective and Criteria 34

Downlisting criteria 34

Delisting criteria 35

1-3. Stepdown Narrative 36

C. Literature Cited __

D. Personal Communications 60

F. ,n /0! kct’crenccs 61

Iii. ... 1~ienwntation Schedule _

IV. Appendix A: Summary of Comments 67

List of Figures

Figure 1. Distribution of known Aplodoutia rufa subspecies . . .

Figure 2. Distribution of known Point Arena mountain beaver populations 8

List ofTables

Table 1. Museum specimens of the Point Arena mountain beaver 4

Table 2. Known populations ofthe Point Arena mountain beaver 6

Table 3. Chronology of research on the Point Arena mountain beaver 13

vi
I. Introduction

A. DESCRIPTION

The Point Arena mountain beaver (Aplodonhia ru/a nigra,) was listed as a federally

endangered species by the U.S. Fish and Wildlife Service on December 12, 1991

(50 FR 64716). It is also listed as a highest priority “Species of Special Concern”

by the State of California (Williams 1986). This subspecies has been given a

recovery priority number of 3 given that it is faced with a high degree of threat

and has a high recovery potential.

The first published account of mountain beaver. Aplodontia ru/a (Rafinesque),

comes from the journals of Lewis and Clark in 1805 (Godin 1964). The Point

Arena subspecies was originally described by Taylor (1914) as a separate species,

.4plodon;ia nigra, because ofits unique color and certain anatomical features. It

was later revised to subspecies status. Aplodonhia rufa nigra, due to overlap of

characteristics with other subspecies and lack of representative specimens (Taylor

1918). This classification has been upheld through several revisions (Dalquest

and Scheffer 1945. Hall and Kelson 1959, Hall 1981). A considerable degree of

geographical and individual variation exists within subspecies ofAplodontia

(Dalquest and Scheffer 1945). Isolation is probably’ a major factor in the

speciation (ic., the process of differentiation into species and subspecies) of the

genus (Finley 1941).

The mountain beaver has been compared to an overgrown pocket gopher (Ingles

1965) and a muskrat without a tail (Racy 19?% Its body is stout, compact and

cylindrical. An average adult measures slightly more than 30.5 centimeters (1

foot) in length and weighs 0.8 tol .8 kilograms (2 to 4 pounds) (Feldhamer and

Rochelle 1982). The skull is relatively broad, massive, laterally compressed. and

notable for its flat upper surfacc and lack of postorbital processes (spur of bone

above the eve socket) (Hall 1981). Long, stiff whiskers (vibrissae) are present on

the nose. and guard hairs are plentiful in the fur. A little patch of white hair

occurs at the base of each ear. The eves and ears are quite small. Limbs are short,

the fore and hind limbs of about equal length. The forefeet have functionally

1
opposed thumbs, and all digits have long, curved claws. A distinctive feature of

its external anatomy is its cylindrical stump of a tail.

Several characteristics distinguish the Point Arena mountain beaver from other

subspecies. The most obvious is its unique black coloration. The outline ofthe

nasals is also distinctive, as are some cranial measurements (Taylor 1914). A. r.

nigra is also the smallest ofthe Californian subspecies.

The mountain beaver, also known as sewellel, boomer, and many other names, is

not closely related to true beavers (Castor). Aplodontia are considered to be the

oldest group ofliving rodents, being the sole extant member of the superfamily

Aplodontoidea, which has been almost morphologically unchanged in the fossil

record since the Miocene (Simpson 1945). This “living fossil” is thought to be

ancestral to the squirrel family (Shotwell 1958).

B. GEOGRAPHICAL DISTRIBUTION

The Point Arena mountain beaver is known only from its type locality, an area of

about 62 square kilometers (24 square miles), entirely in western Mendocino

County (Camp 1918). The seven subspecies of mountain beaver are found in

cool, moist climates along the Pacific Coast ofNorth America, from southern

British Columbia to Point Reyes, California and east to the Cascade and Sierra

Nevada Ranges (Scheffer 1929) (Figure 1). Four subspecies are found along the

northern coast ofCalifornia the Humboldt mountain beaver (Aplodontia rufa

humboldtiana), the Point Reyes mountain beaver (A. r. phaca), the Point Arena

mountain beaver (A. r. nigra), and the Pacific mountain beaver ~JA.r pac~fica,,).

The Point Arena and Point Reyes subspecies are isolated by considerable

distances (Steele 1986). The Point Arena mountain beaver is about 130

kilometers (80 miles) south ofthe Humboldt mountain beaver, and the Point

Reyes mountain beaver is 100 kilometers (60 miles) south ofthe Point Arena

mountain beaver. The length oftime these populations have been isolated is not

known. Also, note that the Sierra Nevada mountain beaver is not endemic to

California, as it has been collected within the Nevada portion ofthe Tahoe Basin.

Historical records of A. r. nigra are scarce (Table 1). Camp (1918) reported that

2
-.7/ /

< A. r. rufo

A. r. roi<eri

A. r. pacifico

/

A. r. humboldticnc

r. nigro

A. r. phoeo

A 00

I

Figure 1. Distribution of known Aplodontia rufa subspecies

(modified from Godin 1964). ‘

0 100 200 300

~~1

SCALE OF~ MtLES
‘[able I. Museum specimens ofthe Point Arena mountain beaver.

Colhrctor

—

C I Camp

Date

—

9

I eat n

t

ts

~igbt

~gratrn~)

——

C nk

Len~ltn

(fllhflteters)

$kin Skull

—

\

Sk~Irntuin

—

Complete

Museum v.. Cuntrnnents

310 rent X University ot California it [terkele,,

Maseattt ofVertebi Ste /5)1 ipx

Type specimen

C.L. Camp ~—5—l 3 Posit Aretra sir

Alder reel.

Male lJTtkItOsvn 908-~ p 316 mm X X Partial Iniversity of California at Berkeley.

Museum of Vertebrate Zoology

C V (mip ~——lS Port Ateter iii

Alder Creek

I Jnknoxxrr I lrrkirossn linkiroon Ilirkirossir tlnixersits of Calilooria at Iterkeles

Mrisetrm of Vertebrare Zoology

Poor onlx

CL Carttp 7—I 0—I 3 lost \rerr.r or

Alder (<reek

I Inkirosrir Uttknoxxrt Unknoxxn Unkrtown X \ Partial Urtixersirs ofCalifore a at Berkelex

Mosearri of Vertebrate Zorrlrgy

Type sttecurtert

C V Camp -ll -15 Iroirrr Aretra or

Alder Creek

Male Uttktrosxtr 9118 p 325 nrrrr N N Crnrtplete I nix ersity of (altfortria at Berkeley.

Mrrserrtrs of Vertebrate Zoology

Type xpecittren

I. Stirrer 7-I 7~3 I Alder r reek Feirrale Iiirk iv xx rr Urtkttoxx r 326 rtritt Un xersitx f Cal for na at Iderkelex

Mrrserr ii ol Vertebret~ tooloex

DII. .lolrrrsorr

er :1

12—32 t~ Irrkrrosr Is Urrktr srrr IIok rr,xx rr tlnknoxx n Urrknoxvtt N Nrrne Urrrxersiry 9 Cal ifisrura at Berkeles

Muxerrrrr of Vertebrate Zooloe~

W.F. arrd

P Worrd

3~4it0 Point Arena Male

I

Adrilt llttkrrossrr 316 rrrrrr X N N Carnegie Mrrserrrrr of Nateral I listrira Age baned ott errealor evaluation of tooth

eruption and fusion of skull xutures

W.F. and

F. Wood

8-23-39 Point Arerra Ferriale StrSAdstlt Urrknoxxn 306 rrrm X N X Carnegie Muserrrrr of Natriral Hixtor3 Age baxed cm curatire evaluation of tooth

errrption arrd frrsion of skull nutures

W.F arid

F. Woort

8-~3-39 Irnrint Arena Female Admit LJrrkrroxxmr 306 rerri Carnegie Mrrsertrrt ofNatrrral ilistorn Age based on curator evalrrariort of tooth

eruptiort and fusion of skrrll strluren

E.W. Pfeiffer 9-3-SI Clrrisrensco

Rarrels (rrear

Bridgeport

Larrdirrg)

Ferrrale Urrknown 10698 307mm X N None tirrixersit of Califortria at Berkeley

Museum of Vertebrate Zooloox

Reproductive researclr

EW. Pfeiffer 11-25-SI Christensen

Ranch

Female Urrknown 10458 333mm X X None Urtiversity of Califortria at Berkeley,

Mrrseum of Vertebrate Zoology

Reprodrrctive research

B. Jones 4-89 2 triles east of

Point Arena

Female llnknrrsvrr Urrknoxxn Unknosxn N X Complete University of Califonsia at Berkeley.

Museum rtfVertebrate Zoology

Tissue collected and preserved

B. Jones 8-89 Point Arena

(Kiurrey Road at

Maneltester

Beaclr St,tte

Park)

Ferrrale tmnkrroxxn Urrkrrown Unknown N X Complete University of California at Berkeley,

Museum of Vertebrate Zoology

Tissuecirllected and preserved

K. Fits 3-29-94 Hxxx I - Kintrey

Road

Female Unknoxx’n 495 p 310 inns N X Srrnoma State University Vertebrate

Museum

Hit by cae

,1 NOTES: Data results from contacting more than 50 museums and universities anu reviewing data on over .000 mountain beaver specimens.
“colonies” extend from the town of Point Arena to Alder Creek, 12 kilometers

(7.5 miles) to the north. This range was extended north another 7 kilometers (4.5

miles) when animals were collected at Christianson Ranch in 1951 by Pfeiffer. In

1991, when the species was listed as endangered, 10 populations had been located

at Mallo Pass Creek. Irish Gulch. Alder Creek, Manchester Beach State Park,

Lagoon Lake. Lower Hathaway Creek, and Point Arena (U.S. Fish and Wildlife

Service 1991). Currently, at least 26 apparently separate populations are known

(Table 2), including populations along Mills Creek, Mallo Pass Creek, Irish

Gulch, Alder Creek, Manchester Beach State Park, Lagoon Lake, Lower

Hathaway Creek, Point Arena, lower and middle Brush Creek, and Hathaway

Creek (Figure 2). The size ofthe total known population is roughly estimated to

be 200 to 500 animals (D. Steele, T. Wooster, unpublished data).

C. HABITAT

Mountain beaver live in underground burrow systems with openings under

vegetation (Scheffer 1929), often on steep north-facing slopes or in gullies (Steele

1986). The burrows are found in moist areas with well-drained soil (Ingles 1965).

Studies suggest that the most important factors in habitat use are a cool thermal

regime, adequate soil drainage, and abundant food supply (Beier 1989), a high

percent cover ofsmall diameter woody material, and soft soil (Hacker and

Coblentz 1993). Mountain beaver require large amounts oflush vegetation for

survival (Voth 1968). Distribution limits are associated with rainfall and soil

conditions that promote lush vegetation and high humidity within burrows (Voth

1968).

Within the range ofthe Point Arena mountain beaver, the historical conversion of

heavily forested areas to agriculture, including cattle grazing, may have altered the

distribution of populations (T. Wooster in litt. 1997). To date, no burrow systems

ofthe Point Arena mountain beaver have been found in a forest setting oflarge

trees with large root systems (T. Wooster in lilt. 1997). One burrow system was

found in Mills Creek where several ofthe entrances were found under the live

roots of a redwood tree, but the remainder ofthe system was away from the tree in

open. low vegetation (T. Wooster in litt. 1997). Studies done on Oregon

subspecies of mountain beaver (Humboldt mountain beaver and Pacific mountain

5
Table 2. Known populations ofthe Point Arena mountain bcavcr.

5

51882 :AJ8,~A

.7~Ita)~

....

—

Bridgeport [ aridrer

—5FOIAL —IIA~FIAT ~Ot~tIAL TH~8~A~

.:::. .

...

...... ..... ...... —_

CS

IAijO~ OWN~J8SJHI

..... ...

.....

IMATOR YEAR C~)mmEIWrS

Private Possible easement

2 MiLls Creck Nettles, Herbs Grazing Fire. Timber Harvest Proate Wooster 992 1994.

1996 1997

‘stalks Fist Creek CS, ferns Water Diversion Road.s Fire Prisate Steele, Itoosh

Wooster

Shisely

985, 1986.

1997. 1992

1993, 1094.

1996. 1997

4 Iri~1s Golsb R, C Heating Development. Feral Pets,

Roads Trails

Pissate Steele Wooster

istcKa

1

1981, 1985,

1986, l.i94,

1997

BlosIbeirsers lsssli isoleb sod

AIdes Cree,

N CS Grazing’. Fire CDPR Wooster 1992. 1994,

1977

Riddled ssitb bu

Alder Creek stools 999

tribosors (Ilcil livekl

NA NA Draesng, Tsmber Harvest, Fire Pessate Wooster 1992 1997 lisa ssoall roes

7 Aldor Creek, 2nd norrIs 9 Ii

tributary 19Vldcat Creek 1

74~ Alder, ferns Grazing, Timben Harsest. Fire Private Wooster 1992 Tbree scroll ssies

So Alder (seek 299 199— CS, R Grazing, Roads, Heebteides, lout

Traffic

CDPR, Private Steele Wooster 1991, 1985,

1986, 1993.

1994, 1996

Fault area

8b AIdes Creek (Ml I Studs site) 2 12’ 124—’ CS Fire, Mud Slides Hunsan Access CDPR Fitts 1997 MCI Monitoring, Robots popolotion

9a Mosielsestes 5 onsplrs 979

lMancbester Beach)

18 CS, CSr Campground. Feral Pets. Roads, Trails CDPR Steele 1989 1094 Pedestrian impacts

9b Masiclsesirs Complex (Dos us Ii 59

PuridI

43 CS, CSr Human Access CDPR Steele 1985 1989 Skull found

9c Maocbester Cosoples AT&T 911

Faciluuv)

759, CS, CSt Construction, Human Access,

Operation arid Maintenance, Storm

Damage

CDPR, Private Steele 1989, 1989,

1996

MCI Monstorine

9d Mancbester Coosples (AT&T 276

Facility.

MCI Study site)

277 CS, CSt Fire, Operation and Maintenance,

Fetal Pets, Human Access

Private Fins 199’ MCI Monitoring, Point Arena

mountain beaver utilizing ice plant

Ge Mairchester Coirsplrs (Kinney ‘14~

Roud, MCI Studs sitC)

237’ CS, CSt Fire Trails, Feral Pets, lluman Access CDPR Fins 1997 MCI Monitoring

9f Masuchesier Complex IRGA 1119

Campground I

NA CS Pets, Fire CDPR Steele 1986 Small sire

IS Middle Bsiish Csrrk 799 Nt, R Pets, Herbicides Streambed

Disturbance

Prisate Steele’. Ihoosies 1981, 1992,

1997
~0PV~AT1OP~

.

ARF~A

(Ha)

IOgAL

55

lit It ans~s~

~1ABIT4T

TYPR~

J’{.FTEN11AtT*U~$.ATh ~WNIR~SUP EST~ATOR VEAI~ COMN~NT$

II Loossisa Lake Ci stol Pess lure Is Is CI3PR Steele 198s 1080 Recent tire

12 lagoon (seek 11 l’s Osazung Itulusi I suruudos fuse Psusoir Sierle 902

13 Lagoon Creek. seark stubator’s CS I iracuno I ii (ito Corsiduir lute liii air Suede 9c5’s

14 Garcia Rises, Sud soasb

tributary

C ri, \ 9 l’s 18 Otocuuse I c;c ‘uusote’ Sirele 68 ucuccier suluc’ ‘u~u7

icc,

4 I~u~57

I~ Garcia Rucsu 2nd sooth

resburars

<ccc ‘sO 1.5 18 lucceusur lure f’uuuoi Steels IOu..

16 Issuer Harbouios I reek I cs) .1 ( ‘ I) feral (ci’ 18 suds (is,scuu.c Psusuir Siesli, (hoscOiri 1961 lOS’

106, liii

‘‘sic

7a Hasbacs or (cork Ins scuils I (5 I k’s (racier’ c 1’ us air Steels i8 ,,c~trr 1,114 ~,5ijO Possible obsess cci

irubotars 1057

(Lessee Pu,c1cruts

lOb liutbasso1 k cork. lsu sucaub ‘ I 18 ihcscec I

tccri ,lcci ‘si’ fun Fri. cur I uric ii tiosel corsi fc

tnibotans 1 ,Otuioucd Roiceb)

19 Hoilsous as (seek. Icr nonb

irubuutar’s

‘ 33 22 8. CS I irozurc I ,c~ Puss ore Sueric.

(8 cocuer tiells

Iii~),’ Ills

li’sl. 1946

cue small sites

‘I I ppor I toiluauias (reek I 5,5 (6 Groectuc F use ‘s.cair Stuels 59 occurs 19112 10 3

23 Point Suesa Creek 1 9 (scocuccie lletbu,,cles I oral Frts Rccodc Curs ccl Pu

‘sccOO, Psuc sir

Steele 96 cossec lu8s lObe Dor killed (suit Arena tnc.sniOun

21 Gascia Ru’ er 18 lice (riuccie ll..ouor .S.s ess I leeds Pris our 7utobc Vscosier I crib. (097

22 SparishCsrek cc 49 CS Neor Pius ate 66 custer 10115 ‘306

23 Garcia Ricer lot souuulc

tribatars

N S 18 Grozuscie lice

24 Losses ffrosh (reek N 0 18 Graccic.. I Iuuurcaic ilcsscirboosc l5ticcotr Steele i)

8

Streuicce. I I cosicuc lIccioubaner

29 Gorcuo Ricer 4 5 1 0 CarrIe fri acroc ‘iii air’ S’s custer 11117 1909

Winds blollous Rd

26 IIill Creek .1 18 [ircuouc Icuccouri cc dense r, scsi 5.1 Pris ate 66occurs liii’s

riparias Os es

Area (ha) — Area (itt heclares) xsUh ‘sign ofDlirlllltain heuser itCIlh it’s/burross’s; - iota! ~ l3fdrls’sssh — eslimatism techniqites \lfr’s (tran’seet Ijt~e 1jul11. roklgh e’stitttates ofbkfrrslos rftlmberh).

CS~Coastu! Scrub. R~Ripariuls. (St (rIfst~fl Staild C (‘oniferoits: NA - Not A6 ailuhie. ‘(‘l)PR - tulifclrllia I)epartment if Park’s utfd Recreation; Area total urea k3fStfadx

6ite~ Area — total Dkfmber elf bitt robS total number 0! aetiS C butrosvs: ‘ Steele. (fflpLibl dittll (I 992i I Wooster unhittbl. data ( 992. 1993)
Population ID No.

ol

.4

.5

A6

0 10

~ 11

12

13

+ 14

+ 15

• 16

o 17

18

® 19

A 20

~ 21

.22

• 23

• 24

*25

o 26

/A\/ High~y 1

Watercourses

A

Point

Arena

2

•J1,u~h r

Ci~eek~ 4

‘N

‘N ~

Figure 2. Knov~n distribution ofPoint Arena mountain beaver, MendocinoCounty, California

(California Department ofFish arid Game, Point Arena Mountain BeaverDatabase, 1998).

0 1 2 3 Miles

PACIHC

OCEAN

‘*AI~r Creik’

*

4

Point Arena

Mallo Pass &ee~

N

0

I

8

Prepared by: ODEG - G. Gould - 4/7/98
beaver), have confirmed that populations are very low in dense conifer stands

(Hooven 1973). Brushy openings in stands provide suitable habitat that often

supports populations of these subspecies (Hooven 1973).

Populations of the Point Arena mountain beaver are found in a variety of habitat

types including coastal scrub, coastal strand, conifer forest, and riparian plant

communities (Steele 1986). The vegetation at the Point Arena, Lower Hathaway

Creek. Lagoon Lake. Alder Creek. and Mallo Pass Creek sites is coastal scrub.

Common coastal scrub species include cow parsnip (Heracleum lanatu,n,~, coyote

brush (Baccharis pi/zdcris). wax myrtle (Mvriea cali/braica). California

blackberry (Ruhus ursinus). salmonberrv (R spectabilis), and thimbleberry (R.

parvi/lorus). Riparian vegetation is present atseveral population locations.

Common species include skunk cabbage (Lysichitum americanun~, horsetail

(Equiselurn telmateja), willows (Salix lasiolepis and £ sitchensis,), red alder

ilnus rubra,), wood rose (Rosa gymnocurpa). and California blackberry. The

Irish Gulch site has a conifer overstory with Douglas-fir (‘Pseudolsuga menziesii,),

grand fir (Abics grandis), and Bishop pine (Pinus muricataY The understory

includes elements of both riparian and coastal scrub habitats, including

thimbleberr, stinging nettle (Urlica sp.). sword fern (Polvstichu,n mnunitunp,

sal monberry. and elderberry (Samb ucus sp.)

At least three mountain heaver sites at Manchester Beach State Park occupy a

habitat type that differs from that of other populations (Steele 1986). These

populations are found in stabilized dunes dominated by bush lupine ‘Lupinus

arhoreus and other coastal strand species including coyote brush, coast goldenrod

(.%o/idago .~pathuhaa) dune grasses, and ice plant (Yiarpohro/us spj. The soil on

these dunes is more stabilized and compacted than that found on open dunes,

there is substantially more ground cover, and burrow openings are found under

shrubs. These sites offer less cover, fewer food plants, and poorer burrowing

conditions than other A. r. nigra sites, but these small populations seem to have

persisted over 10 years of observation (D. Steele pers. obs.).

A recently discovered population (population i.d. #21 in Table 2), on the south

side of the Garcia River, is about 15 meters (50 feet) from the river, between a

riparian zone dominated by red alder and California laurel (Umbellularia

9
cal~fornica), and a hill slope forested with redwood (Sequoia sempervirens) and

grand fir. The colony area is covered by dense, 1.0 to 1.2 meters (3 to 4 feet) high

vegetation dominated by cow parsnip, stinging nettle, horsetail (Equisetum

arvense), and California blackberry. Shrubs ofcascara (Rhamnuspurshiana) and

coyote brush surround the site on all but the north side (A. Mohr pers. comm.

1996).

Large areas of seemingly suitable habitat are unoccupied by mountain beaver.

Camp (1918) noted that (in observations of the Point Reyes mountain beaver)

“overcrowded conditions may prevail in one place, while territory ofthe same

character remains unoccupied nearby”.

In their 5-year study of Point Arena mountain beaver, Northen and Fitts (1993,

1998) investigated the types ofvegetation found in association with this

subspecies. In their studies, vegetative factors were analyzed in terms of their

relationship with total burrows at three sites: Alder Creek, Kinney Road, and the

AT&T site.

Results indicated that burrows are most common in moderately tall vegetation of

mesic sites; presence of burrows correlated significantly with plant height on all

sites. According to Northen and Fitts (1993), a grouping of short plants on the

southern portion of Alder Creek was negatively correlated with burrows, but many

ofthe plant species were positively associated with each other, including

California poppy (Eschscholzia ca1~fornica), spring vetch ( Vicia sativa), English

plantain (Plantago lanceolata), sheep sorrel (Rumex acetosella), and geranium

(Geranium spp.).

Overall, the Kinney Road study site (Northen and Fitts 1993) showed the largest

number of plant species that strongly correlated both positively and negatively

with mountain beaver activity, suggesting that the environmental gradient is

steeper between “good~’ and “bad” habitat on this site than the two other sites.

Positive association was observed with Pacific reedgrass (Calarnagrostis

nutkaensis), coyote brush, yellow bush lupine, all tall perennials, and many

smaller associate species. Northen and Fifis (1993) speculate that the larger plants

help establish a ‘~microclimate” in which some smaller food plants grow (e.g.,

10
miner’s lettuce (Claytonia perfoliata spp. perfoliata)).

Northen and Filis (1993) revealed that at least two different associations of taller

plants support mountain beaver; an area dominated by California reedgrass on

Kinney Road, and an area having moist coastal bluff associates on Alder Creek.

Northen and Fitts (1993) hypothesize that the Point Arena mountain beaver is

more restricted to plant species per Se, than to the soil and climatic conditions that

favor such plant associations.

In their 1997 study. Northen and Fitts (1998) found that bugle hedge nettle

(Stachys a,lugoides var. rigida) seemed to be a preferred plant, and was common

on all three study sites. Bush lupine and seaside woolly sunflower (Eriophyllum

sjaechadi/bliu.’n) were also found to be frequently utilized by the mountain

beaver. The data from their 5-year study show that populations have increased on

sparsely vegetated coastal strand on the AT&T site. Here, bush lupine, coyote

brush, ice plant. and wild radish (Raphanus .sativus). as well as various grasses,

have been found to be important for cover, and possibly for nesting material and

food.

Other rare animal and plant species may occur in the vicinity of Point Arena

mountain beaver habitat. These species are birds, including the western snowy

plover (Charadrius alcxandrinu.s nivosus). marbled murrelet (Brachyrainphus

niarmoratus) (B. Valentine in lit.’. 1997), and northern spotted owl (Strix

occidentalis caurina) (B. Valentine in liii. 1997); amphibians, including the

foothill yellow-legged frog (Rana bovlci); fish, including the tidewater goby

Ei~Thgohius newberrvi), Central Calii~rnia coast coho salmon (Oncorhynchus

kisutch) (B. Valentine in liii. 1997), and Northern California steclhead trout

(Oncorhynchus mykis.s’) (B. Valentine in litt. 1997); invertebrates, including

Behren’s silverspot butterfly (Speycria zerene behrensii); and plants, including

swamp harebell (Campanula calfornica). Mendocino Coast Indian paintbrush

(Castilleja mendocinensis), coast lily (Lilium maritimum,) (S. Flowers in litt.

1997), maple-leafsidalcea (Sidaicca rnalachroides) (S. Flowers in litt. 1997),

fringed false-hellebore (Veratrumfimbriatum) (S. Flowers in litt. 1997), pink

sand verbana (Abronia umbellata) (S. Flowers in lit.’. 1997), and Blasdale’s bent

grass (Agrostis blasdalei) (S. Flowers in liz’t. 1997).

11
D. LIFE HISTORYIBIOLOGYIECOLOGY

Little research has been done on the Point Arena mountain beaver. The only

historical records available are from Taylor (1914 and 1918), who first described

the subspecies; Camp (1918), who made some natural history observations; and

Pfeiffer, who in 1951 captured two animals for reproduction studies (Table 3).

Some basic surveying and monitoring have been done since 1982. Most studies

have been conducted on the more abundant subspecies of Aplodontia rufa,

primarily those in Oregon and Washington. Nevertheless, knowledge ofthe

biology and ecology ofthe genus is limited and often based solely on anecdotal

records. Given its ancient lineage, unusual physiological characteristics, unique

food niche and fascinating behavior, this amazing animal could provide insights in

a variety of fields.

Burrows

Mountain beaver are seldom seen, being most often identified by extensive

underground burrow systems that have numerous openings to the outside (Taylor

1914, Camp 1918). These openings are approximately 15 centimeters (6 inches)

in diameter and occur every few feet (Racy 1922). Burrows are usually in

moderately firm soil where digging is easy, but mountain beaver have been known

to dig in other soil types, even sticky clay (Hubbard 1922). Tunnels generally run

within 0.3 meter (1 foot) ofthe surface, but sometimes descend to depths of 1 to

1 .5 meters (3 to 5 feet) (Racy 1922, Martin 1971). Burrow systems vary in size.

Camp (1918) reported a burrow system of A. r. phaca that extended for more than

100 meters (330 feet) in one direction. The burrow territory of a single animal,

however, probably does not exceed 25 meters (80 feet) (Voth 1968). Burrow

excavations have shown that mountain beaver burrows contain narrow tunnels

(Ingles 1965) that seem to be related to animal size, so that the whiskers can reach

both sides (Voth 1968). Tunnels seem to meander with no apparent plan

(Scheffer 1929). The direction, extent, and placement of runways and openings is

determined by external factors such as obstructions, soil composition, bank slope,

etc. (Scheffer 1929). Burrow openings may be used for entrance and exit, for

pushing out excavated earth or debris, or may result from erosion or cave-ins

(Scheffer 1929). Burrow activity decreases in the winter (Scheffer 1929).

12
Table 3. Chronology of research on the Point Arena mountain

beaver.

Author Reference Corn

Taylor. W. A previously undescribed Aplodonria from the

middle north coast of California. University of

California Publications in Zoology 12:297-300.

1914 Taxonomy

Camp. C. Excavations of burrows of the rodent .4plodontia

xx’ith observations on the habits of the animal.

University of California Publication in Zoology

17(1 8):5t7-535.

1918 Natural history

observations,

specimens collected

Pfeiffer, E. The reproductive cycle of the female mountain

beaver. Journal of Mammalogy 39(2):223-235.

1958 Reproduction,

specimens collected

Steele, D. An ecological survey of mountain beaver

(.lplodontia rufa) in California. Non-game

Wildlife Investigations, Job lV-16.t, California

Department of Fish and Game.

1982 Preliminary survey

based on museum

records

Steele. D. A review of the population status of the Point

Arena mountain beaver (Aplodontia rufa nigra).

Final Report No. 10188-5671-5, U.S. Fish and

Wildlife Service, Sacramento Endangered

Species Office.

1986 Population surveys

Steele. D. An ecological survey ofthe Mountain Beaver

(Ap/odontia ruJ~) in California. 1970-83.

Wildlife Management Division Administrative

Report No. 89-I.

1989 Revision of 1982

report

Northen, P. and

K. Fins

Monitoring of the Point Arena mountain beaver

for MCI Telecommunications Corp. (Year One

through Year Five Reports)

1993

-

1998

5-year mitigation

monitoring

13
Voth (1968) found that mountain beaver cut and store about 2.5 times more food

than they eat. However, through part ofthe winter season or during the full moon,

much less is harvested than is eaten, suggesting storage facilities for as much as a

2-week supply offorage. Storage locations are numerous, including outside

caches, covered caches, and food chamber caches(Voth 1968).

Mountain beaver are not colonial animals and exhibit little social interaction

(Scheffer 1929). The burrows ofseveral animals are often connected, which led

early investigators to misname them “colonies” (Camp 1918), a misconception

that continuesto create confusion. Mountain beaver exhibit a “contagious”

distribution, that is, the presence of one or more animals in a given area seems to

encourage the settlement ofothers (Goslow 1964). However, they are solitary

animals, except during a short breeding period (Godin 1964).

Mountain beaver are not found in continuous burrow systems, one after the other

(T. Wooster in litt 1997). Populations are generally found in a “clumpy”

distribution (Cafferata 1992) with groups ofburrow systems separated by varying

distances.

Population Density

There are no hard data available on the density ofthe Point Arena mountain

beaver population. Population estimates are crude, and have been based on

observations and conservative counts ofapproximately 5 to 10 burrow openings

per animal. The burrow openings that honeycomb the ground may appear to

indicate a large population, but this is probably not the case. Population density is

difficult to determine, because several animals may share the same contiguous

burrow system with each individual’s portion having many openings to the

outside. Camp (1918) found a total of 11 A. r. phaca in a burrow system

measuring 30 by 152 meters (100 by 500 feet), with over 100 burrow entrances.

Population estimates have ranged from 0.61 to 0.81 individuals per hectare (0.25

to 0.33 per acre) in studies ofA. r. ri~’/~i and A. r. pacyfica, respectively (Neal and

Borrecco 1981, Lovejoy and Black 1979), to 3.6 to 4 individuals per hectare (1.5

to 1.6 per acre) in a study ofA. r. phaea (Camp 1918). Temporarily high densities

have been estimated at 6.5 per hectare (2.6 per acre) in studies ofA. r. pacifica

14
(Voth 1968). At least one small site in Kings County, Washington, had a

mountain beaver density of 14 per hectare (5.7 per acre) (Morris et al. 1995).

Nest

There are five types ofunderground chambers within mountain beaver

burrows—nest. food, refuge, fecal pellet, and earth ball storage (Voth 1968). The

nest is an enlarged chamber, often 50 to 60 centimeters (20 to 25 inches) in

diameter and 36 centimeters (14 inches) high, and is usually deeper than other

parts ofthe burrow (Voth 1968). Nests used by adults may contain as much as 0.3

square meter (1.2 square feet) of vegetative material, while subadult nests contain

less (Martin 1971). Voth (1968) found differences between the nests of males and

females, both in nesting material and the fact that female nests had fewer

parasites. Nests are constructed of two shells—an outer shell ofcoarse

vegetation and an inner shell with soft, dry vegetation (Martin 1971). Only one

animal lives in a nest (Hubbard 1922, Martin 1971).

Mountain beaver spend about 75 percent oftheir time in the nest chamber (Ingles

1959, Kinney 1971). The burrow system and nest chamber offer a cool, moist

refuge in the summer and a warm and protected environment during the winter

(Johnson 1971).

Burrows also contain earth ball storage chambers in which “mountain beaver

baseballs” are stored (Voth 1968). These “baseballs” are rocks or lumps ofhard

clay encountered while digging. They usually weigh about 80 to 200 grams (3 to

7 ounces). They may be used for two purposes: 1) to close nest-feeding chambers

during the animal’s absence. and 2) to provide abrasive material to trim their

incisors (Camp 1918. Voth 1968).

Burrow Community

Mountain beaver burrow systems support a community of vertebrates and other

animals (Scheffer 1945). Skunks, salamanders, moles, voles, shrews, chipmunks,

ground squirrels, mice, woodrats. gophers, weasels, mink, hares, and brush rabbits

have all been recovered from mountain beaver burrows (Pfeiffer 1953, Voth 1968,

15
Whitaker et al. 1979, Maser et al. 1981). These animals may have been present as

commensals, predators, or by accident.

A unique invertebrate fauna also associates with mountain beaver. Perhaps the

most striking example is Hystricopsylla schefferi, the largest flea in the world,

which grows to 9 millimeters (0.5 inch) in length (Scheffer 1929). An

invertebrate community also lives in the fecal pellet chambers and aids in

decomposition (Voth 1968). Several species of host-specific mites are associated

with mountain beaver (Whitaker et al. 1979). Other parasites include ticks and

tapeworms (Canaris and Bowers 1992). Neither lice (Scheffer 1969) nor

nematodes (Canaris and Bowers 1992) have been identified from mountain

beaver. The parasite community ofthe Point Arena mountain beaver has not been

investigated.

Cleanliness

Mountain beaver are fastidious creatures (Wright 1969) that keep their tunnels

clean and free of debris (E. Ingles 1960). Special blind tunnels are used as refuse

and fecal chambers (Martin 1971). Unused portions ofvegetation are placed with

other discarded materials in the refuse chamber (Voth 1968) or pushed out of

burrow openings (D. Steele pers. obs).

Defecation is accomplished in a precise manner in which the animals takes each

fecal pellet in its mouth as it is extruded from the anus and tosses it with a flip of

its head into the fecal pile (Kindschy and Larrison 1961). This is done for 2 to 5

minutes at a time. An average of40 to 160 pellets during a 24-hour period is

produced in the field (Voth 1968). One out of every 10 to 13 pellets is reingested

directly as it is expelled (Ingles 1961). These special pellets are soft, green and

larger than the brown, hard pellets which are discarded. The function ofthis

coprophagy is not known, but it may allow maximum use of nutrients and

vitamins contained in the food (Ingles 1961). A number of other rodents, as well

as rabbits and hares, also form a special kind offeces from the contents ofthe

caecum (the blind pouch which forms the beginning of the large intestine) which

is reingested directly from the anus (Schmidt-Nielsen 1975). Studies have shown

that coprophagy in these other animals has great nutritional importance, providing

16
vitamins, and increasing digestibility, protein utilization, and nitrogen retention.

Foraging

Mountain beaver are strict herbivores (Ingles 1965). They are known to eat a

wide range ofplant species, which often includesjust about all the species within

reach ofthe burrows (Camp 1918, Scheffer 1929). Herbaceous plants are eaten

whole. while woody plants are discarded after the bark has been peeled offfor

food (Scheffer 1929). Clipped vegetation can often be observed near burrow

systems (D. Steele pers. obs.).

Mountain beaver are voracious eaters (E. Ingles 1960). Studies have shown that

73 percent oftheir active time is spent gathering, handling and eating food (Ingles

1959). They seldom venture far from their burrows, which may open directly into

suitable vegetation (Camp 1918, Martin 1971). The animals forage for short

distances above ground and then carry or drag the cut vegetative material, which

max’ vary in length from a few inches to several feet, to the burrow (Scheffer

1 929). There. the material is cut into short sections at the burrow entrance and

carried into the burrow to be eaten or stored (Scheffer 1929, Martin 1971).

Animals max’ eat vegetation outside ofthe burrow, but most often consume it in

feeding chambers. adjacent to the nest (Martin 1971).

While mountain beaver gather many ofthe plants in their vicinity, there seems to

be a decided preference for certain types ofplants (Camp 1918, Voth 1968, Allen

1969) including shrubs and smaller trees (Crouch 1968). The coastal mountain

beaver subspecies are predominantly fern and root eaters (Camp 1918). Some of

their preferred foods include plants that are unpalatable ortoxic to other mammals

such as bracken fern (Pteridium aquilinum), sword fern, stinging nettles, thistles

(Cirsium spp.), corn lily ( Veratuni sp.), salal (Gaultheria shallon), foxglove

(Digitalis purpurea), larkspur (Delphinium sp.). and skunk cabbage (Voth 1968,

Lacy 1991). This gives the mountain beaver a largely uncontested food niche

(Johnson 1971). This ability to consume plants with such a variety oftoxic

secondary compounds is unusual and may’ involve a metabolic “cost” to the

animal (Lacy 1991).

17
Many observers have described a behavior called “haystacking,” in which

mountain beaver cut bundles of plants and lay them on logs or on the ground to

wilt (Camp 1918, Godin 1964, Voth 1968). Haystacking has generally been

assumed to provide dried vegetation for nesting or food storage (Scheffer 1929).

Voth (1968), however, suggeststhat the purpose of haystacking is to regulate the

moisture content ofthe food by mixing wilted with fresh vegetation.

Activity

Aplodontia are mostly nocturnal animals but they are seen in the daytime (Ingles

1959, Wright 1969). During a study by Ingles (1959), mountain beaver exhibited

6 to 7 activity periods in a 24-hour period, with a total of 8 to 9 active hours and

15 to 16 hours ofrest. The longest rest period was in the daytime (4.25 hours) and

the longest activity period (2.75 hours) at night. This study showed that

Aplodontia may be active outside its burrow at any hour, but is 50 to 60 percent

more active at night (Ingles 1959).

Bright sunlight appears to make Aplodontia drowsy (Godin 1964). Mountain

beaver have been observed to stop while foraging or even in mid-flight, nod, and

then fall asleep in open, unprotected areas. This seemingly nonadaptive

“narcolepsy” may be a reaction to bright light, warmth, panic or other conditions

(Goslow 1964, D. Steele pers. obs.).

Mountain beaver do not hibernate (Scheffer 1929). They remain active during the

winter (Hall and Kelson 1959, Ingles 1965), although activity decreases during

this time ofyear (Voth 1968).

Data from radiotelemetry studies on animals in Washington showed that 90

percent ofthe animals remain within 24 meters (80 feet) oftheir nest chamber

(Martin 1971). The average home range (the above-ground area in which the

animal forages) varies depending on habitat and has been reported as 0.08 to 0.16

hectares (0.2 to 0.4 acre) with no apparent difference in mean ranges of males and

females (Martin 1971, Neal and Borrecco 1981). A scrotal male moved 197

meters (350 feet) from his nest as compared to a maximum movement of49

meters (160 feet) for all other animals studied (Martin 1971). Mountain beaver

18
walk with a wide, shuffling gait, “like a bear” (Fisler 1965). They can run

backwards as quickly as forward, an obvious advantage for narrow tunnel living

(Camp 1918, D. Steele pers. obs.). They can also climb trees (L. Ingles 1960),

sometimes to a height of4.6 meters (15 feet) (Herlocker 1950).

While not aquatic animals, mountain beaver do not avoid water. For the northern

subspecies. surface water is known to be diverted down burrows (Herlocker

1950), and they wade through partially Hooded tunnels going about business as

usual (Scheffer 1929). They traverse puddles and streams and can swim (Scheffer

1929. E. Ingles 1960). When free water is available, mountain beaver bathe

regularly while digging or foraging (Goslow 1964).

Thermoregulation

One explanation for the limited distribution of mountain beaver is their limited

ability to thermoregulate (i.e., regulate body’ temperature) (Johnson 1971. Kinney

1971). They seem to tolerate low temperature extremes better than high ones,

with a lethal body temperature of about 42 degrees Centigrade (108 degrees

Fahrenheit) (Johnson 1971). When exposed to high ambient temperatures,

animals in captivity respond by either reducing their activity and changing their

body conformation (sprawling out their body), or by attempting to escape (Kinney

1971). Mountain beaver lack such behavioral responses as panting or salivation

to reduce heat stress (Johnson 1971) and do not sweat. An annual summer molt

decreases insulation, letting them tolerate greater heat (Johnson 1971).

Burrows provide a highly stable microclimate (Kinney 1 971). Tunnels, and

especially the nest chamber. which is lower in elevation and insulated with nesting

material, maintain a stable temperature gradient (Kinney 1971). Daily

temperature variation never exceeds 4 degrees Centigrade (7 degrees Fahrenheit),

and the mean annual range is from 2 to 14 degrees Centigrade (36 to 57 degrees

Fahrenheit) (Johnson 1971). The burrow maintains a relative humidity of nearly

100 percent (Voth 1968).

The Point Arena area has a relatively mild climate due to the buffering effect of

the ocean. Little range in temperature occurs either daily or annually, with

19
average temperatures between 7.0 to 16.2 degrees Centigrade (45 to 61 degrees

Fahrenheit) (U.S. Weather Bureau 1963). Point Arena has one ofthe longest

growing seasons in California, over 300 days annually (Steele 1989).

Osmoregulation (Water Balance)

The mountain beaver has a very simple kidney structure that lacks the anatomical

features necessary to concentrate urine effectively (Pfeiffer et al. 1960, SchmidtNielson and Pfeiffer 1970). It has been suggested that Aplodontia might have

been one ofthe first mammals to have a primitive renal mechanism for

concentrating its urine (Dicker and Eggleton 1964). One consequence ofthis

inability to concentrate urine is that mountain beaver require large quantities of

water to replace that lost through excretion (Nungesser et al. 1960, Dolph et al.

196;’ Nungesser and Pfeiffer 1965). a need that may be a major reason why

mountain beaver are restricted to moist environments (Pfeiffer 1965). Mountain

beaver consume about 33 percent oftheir body weight in water daily and excrete

most ofthis in urine (Nungesser and Pfeiffer 1961). Animals in captivity are

known to drink a great deal offree water (Pfeiffer 1953, Schmidt-Nielson and

Pfeiffer 1970). Iffree water is withheld, animals in captivity (A. r. pac~fica) have

survived for periods ofseveral months without apparent distress, obtaining water

entirely from the succulent vegetation they consume (Fisler 1965, Johnson 1971).

The importance offree water for Point Arena mountain beaver is not known.

Some populations seem to live a considerable distance from free water. At these

locations, free water comes from ephemeral puddles that form during rainstorms.

The marine climate around Point Arena includes significant amounts ofmoisture

from fog. Condensation of fog may provide adequate free water.

Behavior

Mountain beaver can be aggressive animals, have been called “cantankerous” or

“vicious~’ (Smurthwaite 1986). and are swift, strong biters (Maser et al. 1981).

However, captive animals have been reported to become quite docile and even eat

out ofpeople’s hands (Davis 1941, Herlocker 1950), although they do not exhibit

affection or friendliness (Herlocker 1950, Smurthwaite 1986).

20
Territorial behavior is strong in mountain beaver (Nolte et al. 1993). Pfeiffer

(1953) reports that males will kill females or other males ifthey are placed

together in the same cage. Battles are common when animals encounter one

another (Herlocker 1950). Although nests are defended fiercely. it is thought that

tunnels are used in common by animals in a burrow system (Scheffer 1929). The

response to meeting in a tunnel is unknown. Animals may forage in the same

home range and meet with no apparent territorial response (Martin 1971). The

fact that thex’ tend to live in close association suegests some level of tolerance,

perhaps based on chemical cues.

Mountain beaver have two scent glands at the base of their tail (Racy 1922).

These give the animals a strong body odor, and may be a primary means of

recognizing their own kind (Scheffer 1929). A sweet, musky smell in the urine is

distinctive (Kindschy and Larrison 1961), and becomes accentuated during the

breeding season (Fisler 1965). Scent-marking behavior has been observed (Nolte

etal. 1993).

Mountain beaver produce large amounts of a milky eye secretion, which can at

times cause their eves to close. This secretion may be an indication of stress in

captive animals (D. Steele pers. obs.), or a defense against eye damage while

excavating (Maser et al. 1981). It has also been suggested that the eye secretion

may induce a tonic immobility to avoid attack or may function in chemical

communication (Nolte et al. 1993).

Senses

As is true of many’ burrowing animals, mountain beaver have highly developed

tactile senses and will respond qtticklv to the slightest disturbance oftheir guard

hairs or whiskers (Camp 191 8. Scheffer 1929). Their senses of smell and taste

also seem to be well developed. They will frequently raise their noses to sniff the

air (Camp 1918, Voth 1968), and feeding is reduced when food is exposed to

predator odors (Epple et al. 1993) or other repellent material (Campbell and

Evans 1989). Their eyesight is poor and animals will frequently bump into

objects in their path (Fisler 1965). Night vision is better than day vision (Voth

1968).

21
Although mountain beavershow little response to sharp noises (Fisler 1965), little

is actually known about their auditory acuity. The possibility that mountain

beaver can detect low or even very low frequencies is under investigation (R.

Heffner pers. comm.). Aplodontia also has a very large and unique cochlear

nuclear complex in the brain, which may indicate the ability to detect subtle

changes in air pressure, perhaps an adaptation to burrow living (Merzenich et al.

1973).

Several types of vocalizations have been attributed to mountain beaver, including

grunts, growls, cough-like sounds, sharp, high pitched coughs (Fisler 1965), and a

harsh chattering-grating sound produced by gnashing the teeth (Maser et al. 1981).

Scheffer (1929) states that mountain beaver do not whistle, but Kindschy and

Larrison (1961) reported a shrill, whistle-like squeal from their captive animal.

Mountain beaver do not make booming noises, as erroneously believed by early

observers (Scheffer 1929).

Demographics

No information is known on the demographics ofthe Point Arena mountain

beaver. In general, mountain beaver have an unusually low reproductive rate for a

rodent (Pfeiffer 1958). Females typically do not breed until their second year

(Pfeiffer 1958), and the breeding season is short and well-defined (Lovejoy and

Black 1979). Females are monestrous, that is, they produce only one litter a year,

and all breeding females ovulate at about the same time (Pfeiffer 1958). The

gestation period is 28 to 30 days (Scheffer 1929, Pfeiffer 1958). Litters consist of

two, three, orrarely four (Scheffer 1929, Dalquest 1948) or five (Herlocker 1950,

Maser et al. 1981) offspring.

Newborn Aplodontia are naked and blind at birth (Cramblet and Ridenhour 1956,

Lovejoy et al. 1978). Growth is rapid, and within 2 weeks, newborns are

completely covered with hair (Lovejoy and Black 1974). Lactation extends for

about 2 months (Pfeiffer 1958, Lovejoy and Black 1974). Pregnant and lactating

females have a dark patch of mammary hairs around the nipples, which may be a

physiological relict lost by more advanced mammals(Pfeiffer 1955).

22
Juveniles have fine, gray fur, but within a year most have a coarse pelage and are

difficult to distinguish from adults (Lovejoy and Black 1974). Pfeiffer (1958)

identified four age classes, based on the degree ofclosure ofthe epiphyseal

femoral suture and tooth wear. Voth (1968) identified eight classes based on

weight. Lovejoy and Black (1979) worked with three age groups based on both

weight and external characteristics and questioned the validity of weight classes.

Mountain beaver are thought to live at least 5 to 6 years (Lovejoy and Black

1979).

Male and female Aplodontia are not easily distinguished by external

characteristics (Scheffer 1929, D. Steele pers. obs.), except in the breeding season

when it is easy to distinguish male and female genitalia when visible (Godin

1964). Females are on average slightly smaller (Lovejoy and Black 1974), but not

enough to be a diagnostic difference. During the breeding season, the sexes of

adults can be distinguished because the testes in males, which are normally

abdominal, become semiscrotal (Pfeiffer 1956. Lovejoy et al. 1978). Pregnant

and lactating females can be identified by the dark hair around the nipples

(Pfeiffer 1955).

The sex ratio ofjuvenile Aplodontia is 1:1 (Lovejoy and Black 1979). However.

trapping results of adult animals have indicated a skew-ed sex ratio of 3:1 favoring

males (Hubbard 1922). Other trapping studies have also shown a preponderance

of males, at levels of 63.6 percent (Voth 1968), and 61.9 percent (Lovejoy and

Black 1979). This may be a true representation ofthe population and not an

artifact oftrapping (Lovejoy and Black 1974). but no explanation has been given

for this phenomenon.

No data are available on reproduction of Point Arena mountain beaver. The

breeding season is thought to be from about mid-December to early January,

based on data collected by Pfeiffer (1958) on Ap/odontia rufaphaca, the Point

Reyes mountain beaver. Gestation would then be from about mid- to lateJanuary, and animals born in late January might begin to forage for themselves by

early April. Size oflitters, survival of young, sex ratio and other demographic

information are unknown for the Point Arena mountain beaver.

23
Juvenile dispersal is generally thought to be completed by early fall. Also,

dispersal ofjuvenile Aplodontia is thought to be primarily through excavation

within the burrow system (Blair 1953), although some overland migration is seen

(Martin 1971). Of 11 subadult animals monitored through radiotelemetry, 9

remained near the initial site ofcapture while 1 moved as far as 564 meters (1,850

feet). There seems to be no real difference between the movement of males and

females (Martin 1971).

Dispersing animals may make several attempts to establish a nest before finding a

suitable situation (Lovejoy and Black 1979, Martin 1971). Once the animal

establishes its nest site, the site is used for long periods oftime (Martin 1971).

Animals may move quickly into an unoccupied nest (Martin 1971, Nolte et al.

1993).

Mortality factors are not easily studied in underground species. Mountain beaver

are known to be prey ofbobcats (Lynx rufus), fishers (Martespennanti), coyotes

(Canis latrans), great horned owls (Bubo virginianus) (Ingles 1965), striped

skunks (A<fephitis mephitis), eagles (Accipitridae family), minks (Mustela vison),

and other predators (Ingles 1965, Knick 1984). Little is known of other mortality

factors such as disease.

Aplodontia are not considered valuable game or fur animals today (Ingles 1965)

although, in the past, Native American Indians wore robes made ofmountain

beaver and valued their meat (Herlocker 1950). The Indian robes, called “shewal-lal,” were the origin ofthe mountain beaver nickname, sewellel, which Lewis

and Clark misunderstood to be the name ofthe animal (Godin 1964).

Fragility

There is no information on the Point Arena mountain beaver in captivity. At least

one Point Arena mountain beaver was trapped and held for several days without

any apparent harm, and several individuals have been live-trapped and released

with similar results (D. Steele pers. obs.). Observations based on other subspecies

provide conflicting reports on the species’ fragility. Camp (1918) stated that

Aplodontia are not hardy and do not live long if injured in the least. Pfeiffer

24
(1953) noted that some animals recovered from injury and even from biopsies of

parts of the reproductive system. Captured animals in the Pacific Northwest have

a high trap mortality (Dodge and Campbell 1965, Lovejoy and Black 1979) and

mountain beaver are known to die unexpectedly in captivity (Kindschy and

Larrison 1961, D. Steele pers. obs.). Others report that mountain beaver are easy

to maintain in captivity for long periods of time (Fisler 1965, Davis 1941).

The sensitivity of mountain beaver to disturbance is not well known. Although

most burrow openings are in isolated areas or under dense vegetation or on steep

slopes, a population ofAplodontia rufa nigra has coexisted since at least 1981

with campers in the Manchester Beach State Park campground (D. Steele pers.

obs.). However, crushing of vegetation and burrows by campers at Manchester

Beach State Park resulted in a decrease in active and new burrows near the

campground (S. Flowers in litt. 1997, K. Fitts in litt. 1997). Scheffer (1929)

reported that animals remained in their burrows despite clearing of vegetation,

nearby blasting, burning oflog and brush piles, and obstruction of burrow

openings. Similar observations were made by Campbell et al. (1988) in studies in

the State of Washington. Gyug (1997) noted that ground disturbance resulting

from logging was inversely related to the presence ofmountain beaver in southern

British Columbia. The 1995 Mt. Vision fire at Point Reyes National Seashore

may have destroyed 50 to 60 percent of the available Point Reyes mountain beaver

habitat with very low survival in these populations (G. Fellers pers. comm. 1996).

Pest Control

The Calilbrnia subspecies ofmountain beaver are generally found in low numbers

in isolated areas. However, in other portions of its range, especially in

Washington and Oregon, mountain beaver are thriving and considered pests

because of damage inflicted on commercial Douglas-fir plantations (Martin 1971,

Maser et al. 1981, Smurthwaite 1986). The Point Arena subspecies is not known

to cause problems beyond some minor garden pilfering and burrows in unwanted

places.

25
E. REASONS FOR LISTING AND THREATS TO SURVIVAL

The vulnerability of the Point Arena mountain beaver results from two basic facts:

1) this subspecies has few populations, all ofwhich have an extremely limited

distribution; and 2) the number ofindividuals in the populations are presumed

low. Add to this its low reproductive rate, and any catastrophe, whether natural or

human-caused, has a high potential to severely impact the subspecies. Urban

development and related facilities, livestock grazing, human disturbance, riparian

habitat destruction, transportation and utility corridors, and catastrophic natural

events all pose some degree of direct or indirect threat to Point Arena mountain

beaver at various locations. However, the extent to which each ofthese factors

threaten Point Arena mountain beaver populations is largely unknown. Several of

these factors may pose a greater threat to this subspecies, but no quantitative

assessment ofrisk has been made.

Historically, the conversion ofheavily forested areas to agriculture, including

grazing, may have created suitable habitat for Point Arena mountain beavers in

some areas (T. Wooster in litt. 1997). Conversely, livestock grazing may have

substantially reduced the extent of historical coastal scrub habitat in the area

(Steele 1986) offsetting any gains from forest conversions. Today, grazing is

considered to be the most important factor limiting the expansion of extant Point

Arenamountain beaver populations (T. Wooster in litt. 1997). Many populations

are found near agricultural or ranch land and are impacted by livestock that step

on Aplodontia burrows and destroy runways (D. Steele pers. obs., Steele 1986).

Sheep and cattle grazing at the AT&T communications facility also may have

impacted the mountain beaver population there.

Urban development and associated activities may directly or indirectly affect

mountain beaver populations. At Irish Beach, the mountain beaver population at

this site (Irish Gulch) may have been affected indirectly by trash dumping and an

increase in predation by feral and nonferal house pets. Construction of private

and county roads has also resulted in some habitat loss, such as along Hathaway

Creek where a population was bisected by an access road to a residence (T.

Wooster in litt. 1997). The latest revision to the Mendocino County Land Use

Plan shows additional housing developments, creating a potential for additional

26
indirect and direct disturbance to the mountain beaver population in the Irish

Gulch area.

Transportation and utility facilities may adversely affect mountain beaver in

various ways. Recent fiber optics projects have drilled under Point Arena

mountain beaver populations and caused noise, vibration, and some physical

impacts to their habitat. The significance ofthese actions is not known and needs

further monitoring. Habitat loss is likely as a result of construction and secondary

impacts from use ofthe AT&T communications facility. It is not known how

large this mountain beaver population was prior to construction ofthe

communication facility, but the present population roughly estimated at about 20

animals, continues to be impacted by pedestrians and occasional project activities.

Roadways may reduce or eliminate the ability of young Point Arena mountain

beaver to disperse successfully from natal areas. Three observations ofmountain

beaver killed crossing Highway 1 have been made, one at Gasker Slough bridge

(K. Joe pers. comm.), and two at Kinney Road (D. Steele pers. obs., K. Fitts pers.

obs.). Populations at Lower 1-lathaway Creek, Alder Creek, Manchester Beach

State Park, and Irish Beach have burroxvs near roadways (Steele 1986), and

therefore, may be subjected to higher mortality rates than other populations. It is

not known ifthese populations were present before road construction, but they

have persisted since being discovered.

Human disturbance from recreational activities also may adversely affect

mountain beaver populations. At Manchester Beach State Park, campers had

xvandered offthe designated trails into mountain beaver habitat, thus trampling

x egetalico ana crushing burrows. This impact resulted in a decrease in active and

new burrows near the campground and on trails. Three campsites were closed to

the public in 1995. Since closure, fresh burrows have been excavated (Fall 1995.

175 burrows; Fall 1996, 215 burrows) and increased activity in established

burrows has been noted (S. Flowers in litt. 1997. K. Fitts in litt. 1997).

The Irish Beach-to-Manchester Alternative Coastal Trail has been proposed to

provide non-vehicular beach access at Irish Beach, Alder Creek Beach Road,

Kinney Road, and Stoneboro Road. This project includes construction of a

parking area, an interpretive center, and access to the proposed trail at both Irish

27
Gulch and Alder Creek. Also, the town of Point Arena plans to develop a trail

along Point Arena Creek. These projects could increase human disturbance to

mountain beaver populations and could reduce habitat quality. No information

exists on how the Point Arena mountain beaver would react to such human

disturbance.

Unauthorized destruction ofriparian habitat continues to occur on a regular basis

within the range ofthe Point Arena mountain beaver (E. Ramos pers. comm.). In

some cases, unauthorized activities have resulted in destruction of mountain

beaver habitat or potential habitat from heavy equipment use, vegetation cutting,

and/or vegetation burning (D. Steele pers. obs.). A study by Motobu (1978) on

the effects of controlled slash burning on a population of Washington mountain

beavers (A. r. ruJd), revealed that fire substantially reduced the mountain beaver

population within burn units. Also, predator activity increased substantially

within the burn units after the fire.

Succession ofshrubby open habitat preferred by the Point Arenamountain beaver

to dense, closed canopy forest may threaten mountain beaver populations at

several locations (T. Wooster in litt. 1997).

Pest control is an on-going threat to A. r. nigra. Past gopher control programs in

western Mendocino County may have impacted Point Arena mountain beaver.

Maintenance workers at the KOA campground near Manchester Beach State Park

placed poison bait and traps out to kill mountain beaver they mistakenly thought

to be gophers. Rodent trapping and baiting, often associated with residences and

gardens. is still common along the Mendocino Coast (Steele 1986). Baits laced

with strychnine or anticoagulants are the most widely used (Steele 1986). Other

damaging chemicals, to which mountain beaver may be exposed, include copper

sulfate, ~vhich is sometimes applied to wet spots and seeps to control sheep liver

fluke (Steele 1986), and herbicides. which are regularly sprayed on vegetation

near mountain beaver populations to maintain road edges and utility corridors. No

information is available assessing the impacts ofsuch activities on the Point

Arena mountain beaver. Any mountain beaver that may have succumbed to

chemical poisoning would likely have died unobserved within its burrow. The

small, isolated populations of Point Arena mountain beaver are highly vulnerable

28
to extirpation from lethal chemicals.

Several alien plants occur in Point Arena mountain beaver habitat including gorse

(Ulex europacus,), broom < ‘tisus sp.). pampas grass (‘Cortaderia selloan&,

German ivy (‘Seneejo mikanioides,), ice plant (Mesembrvanthemum sp.), and

European beachgrass (Ammophila arenaria,.). In some areas these species are

established and relatively’ widespread, and may reduce or improve the quality and

quantity of Point Arena mountain beaver habitat. For example, German ivy is

known to be a problem in some areas and spreading, but more survey work is

needed to determine the extent ofdetrimental effects. No specific impacts to

occupied habitat have been documented but are likely (D. Steele pers. comm.).

German ivy favors shady’ and disturbed areas, and is renowned for invading

riparian areas. Native to South Africa, it is generally found below 180 meters

(600 feet) (K. Fuller pers. comm.).

Ice plant is slowly spreading in some older dune areas. Observations of some

mountain beaver burrows at Manchester Beach State Park revealed partially eaten

pieces ofice plants (Fitts 1996, D. Steele pers. obs.), which may provide the

mountain beaver with a year-around food source that is high in water content. Ice

plant also may be beneficial in that its root structure may stabilize sandy soil

through which the mountain beaver burrows (Fitts 1996).

European beachgrass has displaced native vegetation at the AT&T population site

and at Manchester Beach State Park. There are burrows at the edge ofthe habitat,

but no signs offoraging (D. Steele pers. comm.). European beachgrass is found at

several burrows in the Point Arena area. Many ofthe burrows are located

underneath the plants, and runways are found under large clumps of dead

beachgrass. The root system of beachgrass is an important soil stabilizer, and the

canopy provides cover (Fitts 1996).

The importance of alien species, such as ice plant and European beachgrass, to the

Point Arena mountain beaver is not fully known. Further studies should be

undertaken to assess their significance, and careful consideration should be given

to the effects oftheir management on the mountain beaver (Fitts 1996).

29
Little is known regarding diseases ofmountain beaver or their potential to

threaten mountain beaver populations. Animals in captivity have succumbed to

infection and intestinal disease. Mountain beaver are known to harbor tapeworms

and other parasites (Canaris and Bowers 1992).

Mountain beaver are preyed upon by most predators ofsmall mammals including

coyotes, skunks, owls, weasels, raptors, etc. Sign of predation by bobcat on Point

Arena mountain beaver has been reported (T. Wooster pers. comm.) as well as

raptor predation (D. Steele pers. obs.). Domestic and feral dogs are known to kill

Point Arena mountain beaver, and cats are suspected predators of young mountain

beaver. Domestic and feral animal predation would be expected to be greater for

those mountain beaver populations located adjacent to urban and agricultural

developments such as Irish Gulch, Alder Creek, and Point Arena. This is

supported by the discovery ofa Point Arena mountain beaver killed by a domestic

dog (K. Joe pers. comm.). The impact of predation on small populations has the

potential to become critical.

Because Point Arena mountain beaver have a clumped and fragmented

distribution, they are more vulnerable to localized catastrophic events such as

storms, fire, flooding, landslides, disease, or prolonged drought than species

exhibiting a more widespread and continuous distribution. In the last 10 years,

fires, flooding, mud slides, and beach erosion have destroyed Point Arena

mountain beaver habitat at several locations (D. Steele pers. obs.). Natural

disasters could easily eliminate all individuals in a population or further depress

already low population numbers to a point where they could not recover.

Fragmentation would prevent individuals from other populations from

recolonizing unoccupied habitat.

Point Arena mountain beaver population numbers may be so low that the effects

of inbreeding among closely-related individuals could result in an increase in

deleterious genes in the population. Individuals possessing such deleterious genes

are less likely to be capable ofadapting to enviromnental changes, even relatively

minor ones. Moreover, small populations are subject to the effects of genetic

drift, the random decline in genetic variation that can occur in small populations.

This too limits the flexibility ofa population to respond to environmental changes.

30
The effects ofgenetic drift and inbreeding depression are genetically similar.

Habitat fragmentation is a major concern because it can increase the genetic

isolation among populations of mountain beaver. Habitat fragmentation can

reduce population size, thereby increasing the probability ofgenetic drift and

inbreeding depression. This may result in less viable and adaptable populations of

mountain beaver.

F. CONSERVATION MEASURES

The following are efforts to protect Point Arena mountain beaver:

EFFORTS CURRENTL YINPLACE:

o Listing the Point Arena mountain beaver as a federally endangered species

has given the subspecies a certain amount of protection.

o Timber Harvest Plans must determine the presence or absence ofPoint

Arena mountain beaver and take steps to avoid disturbance, if present.

Section C (Biological Resources) of Appendix-Technical Rule Addendum

No. 2 in “California Forest Practice Rules, Title 14, California Code of

Regulations” states that: “Biological assessment areas will vary with the

species being evaluated and its habitat. Factors to consider in the

evaluation of cumulative biological impacts include: 1. Any known rare,

threatened, or endangered species or species ofspecial concern. . . that

.mtv be directly or indirectly affected by project activities...”. Section

1034 describes the requirement ofthe contents ofthe proposed Timber

Harvest Plan, including “information on the presence and protection of

known habitat or individuals of any listed species which may be

significantly impacted by the timber operation.”

o The California Department of Fish and Game’s California Natural

Diversity Database lists known populations of the Point Arena mountain

beaver and provides this information for planning purposes.

31
o The AT&T Corporation has placed funds in an escrow account to be

dedicated for holding and disbursing monies as part ofmitigation for the

bentonite spill of 1992. It was apparently not possible to procure a

satisfactory conservation easement in the Point Arena area, as was

previously anticipated.

o A 5-year study to monitor Point Arena mountain beaver as part of

mitigation for an MCI microwave tower has been completed (Northern

and Fitts 1993-1996, 1998). In this study, burrows were monitored along

transects on the impacted site as well astwo control sites, and data on

vegetation were collected. Construction ofthe MCI facility caused a

decrease in the number and areal extent of active burrows, however, the

project did not adversely affect the Point Arena mountain beaver, and

there has been a gradual recovery since 1993 in active and total numberof

burrows per plot on the impact site (Northern and Fitts 1995, 1998).

EFFORTS CURRENTLY UNDER WAY:

o Due to the Federal listing, planning decisions must take possible threats to

the mountain beaver into consideration.

o Recommendations have been made for the placement oframps to cover

fragile mountain beaver habitat within the Manchester Beach State Park

camping area. However, lack offunds and a “low priority” ranking have

impeded this important method of protection from taking place (S.

Flowers in litt. 1997).

o The City of Point Arena has wording in its General Plan for mapping and

protection ofthe Point Arena mountain beaver, however, the City has not

yet accomplished its General Plan mandated tasks in this area (A. Levine

in litt. 1997).

o The North Coast Regional Water Quality Control Board has completed a

draft report entitled “Staff Report on the Proposal to Include a Water

Quality Attainment Strategy (Total Maximum Daily Load) for the Garcia

32
River Watershed into Section 4, Nonpoint Source Measures, of the Water

Quality Control Planfor the North Coast Region” (1997). This planning

effort by the Regional Board provides an opportunity for the Regional

Board, working with the Mendocino Resource Conservation District

(Garcia River Watershed Enhancement Plan, Mendocino Resource

Conservation District [1992]), to enhance habitat for the Point Arena

mountain beaver during restoration efforts in the Garcia River Watershed

area.

o The U.S. Environmental Protection Agency and California Department of

Pesticide Regulation are in the process ofdeveloping an Endangered

Species Protection Program to protect federally’ listed threatened and

endangered species and their critical habitat from harm due to pesticide

use. In the interim, the two agencies have produced a rodenticide bulletin

entitled “Protecting Endangered Species, Interim Measures for Use of

Rodenticides in Mendocino County” (U.S. Environmental Protection

Agency and California Department ofPesticide Regulation 1998). This

bulletin recommends methods of pesticide application to protect wildlife

species. including the Point Arena mountain beaver.

o The “Manchester State Park General Plan” was prepared by the California

Department ofParks and Recreation in December 1992 (California

Department of Parks and Recreation 1992). The “Directive” for the Point

Arena mountain beaver states: “Any potential habitat not yet investigated

in the unit shall be surveyed for the presence of Point Arena mountain

beaver, and for potential mountain beaver habitat. Perpetuation and

protection of mountain beaver habitat shall be a high priority in

management of both potential and occupied habitat areas. The department

shall work with the Department of Fish and Game and the U.S. Fish and

Wildlife Service in management of this sensitive species, including

cooperating in the determination of critical habitat and in preparing the

recovery plan. Potential habitat and occupied colonies should be mapped

on unit base maps, and should not be available to the general public. If

deemed necessary, occupied habitat areas may be closed to visitor use to

avoid disturbance to shallow burrow systems” (California Department of

Parks and Recreation 1992).

33
II. Recovery

A. OBJECTIVE AND CRITERIA

The objective ofthis recovery’ plan is to delist the Point Arenamountain beaver.

Detailed information on many aspects of the biology, habitat requirements, and

distribution ofthe Point Arena mountain beaver is lacking. The recovery criteria

for downlisting and delisting, therefore, reflect the best biological knowledge and

assumptions regarding the species. These reclassification criteria should be

considered preliminary and may be revised when new data become available.

Downlisting criteria:

I. At least 16 populations are protected from human-caused disturbance in

perpetuity. Each population shall contain at least 20 hectares (49 acres) of

suitable habitat of which at least 10 hectares (25 acres) are occupied

habitat.

2. These populations shall have a mean density of at least 4 Point Arena

mountain beavers per hectare (1.6 per acre) ofoccupied habitat, unless

new data show that a lower density is healthy and stable.

3. All 16 populations are stable (i.e., no more than a 25 percent change in

estimated population size from highest to lowest value) or increasing for a

period of at least 10 years (following attainment of criterion #1), as

documented through establishment and implementation of a scientifically

acceptable population monitoring program.

4. The amount of additional habitat needed for population interconnectivity,

travel, and dispersal habitat (i.e. to prevent inbreeding and genetic drift)

has been determined.

5. Sufficient information is available on the subspecies habitat requirements

and life history to permit adaptive management, and any management

34
actions necessary to ensure the continued success ofthese populations (in

criterion #1) have been fully implemented.

Delisting criteria:

1. Thirty populations are protected from disturbance in perpetuity. Fach

population shall contain at least 20 hectares (49 acres) of suitable habitat

of which at least 10 hectares (25 acres) are occupied habitat.

2. These populations shall have a mean density of at least 4 Point Arena

mountain beavers per hectare (1.6 per acre) ofoccupied habitat, unless

new data show that a lower density is healthy and stable.

3. All 30 populations are stable (i.e., no more than a 25 percent change in

estimated population size from highest to lowest value) orincreasing for a

period of at least 15 years (following attainment of criterion #1), as

documented through establishment and implementation ofa scientifically

acceptable population monitoring program.

4. Additional habitat needed for population interconnectivity, travel ,and

dispersal habitat has been protected and is being managed appropriately.

5. Adaptive management prescriptions have been determined and

implemented for all populations, including repatriated populations if

deemed necessary.

The estimated date for downlisting to threatened status is 2015 and delisting is by

2025.

The goals and objectives stated here are subject to change as more information

becomes available on the Point Arena mountain beaver through the work

undertaken in this recovery effort, and as advances are made in the field of

conservation biology and in our understanding of endangered species.

35
B. STEPDOWN NARRATIVE

1.Protect existing mountain beaver populations

.

Twenty-six Point Arena mountain beaver populations have been found to

date. Long-term habitat protection is vital for the protection ofPoint

Arena mountain beaver populations. Most ofthe threats to the animal are

a result of habitat destruction and degradation. All known populations

must be protected in perpetuity from the threats identified in Section I.E.

(with special consideration for unusual habitats).

I. I Protect existing populations through land acquisitions, easements

.

conservation agreements. or other mechanisms

.

The priorities for land protection should be based on size of

mountain beaver populations, degree ofthreatsto habitat, and

willing landowners. It may be advantageous to look at areas that

would benefit several other species of concern in addition to the

Point Arena mountain beaver. Areas protected should include

appropriate buffersto protect the population from outside

disturbances. Suitable, but currently unoccupied, habitat may be a

necessary reservoir for mountain beaver to ensure population

structure and dynamics (Todd 1990). It is, therefore, necessary to

protect not only habitat currently occupied by mountain beaver, but

also unoccupied habitat to allow for population expansion. Habitat

protection can be achieved through acquisition, easements,

conservation agreements, or other mechanisms, including zoning

ordinances.

1.2 Develop and implement management plans for Point Arena

mountain beaver populations on public lands

.

Management plans should be developed for all populations on

public lands. Methods to minimize or eliminate identified threats

36
to mountain beavers at each population should be included in the

management plan. Management plans should be adaptable to the

results ofresearch and monitoring. Each plan should include

contingencies in the event that the mountain beaver population

declines to low levels. Management measures that should be

considered include fencing to keep out recreationists and grazing

animals, elevated walkways or footpaths to divert foot traffic away

from mountain beaver habitat, open culverts or other devices to

provide safe passageways for mountain beavers under roadways,

vegetation management such as exotic plant control, and control of

domestic and feral animal predation.

1.3 Develop and implement management guidelines to protect existing

populations ofPoint Arena mountain beaver on private lands

.

Guidelines should be developed to include specific policies for

managing existing populations of mountain beaver on private

lands. These policies should address identified threats to the

species such as predation by domestic and feral dogs and cats.

Vegetation management and exotic plant control should also be

addressed. The guidelines should cover pesticide use, domestic

animals, protective measures, etc. A section on emergency

response for contingencies such as fire and other natural and

human-caused disasters should also be included. Implementation

and enforcement should also be covered. These guidelines should

be revised regularly as more information becomes available on the

Point Arena mountain beaver.

These guidelines should be developed and implemented by

agencies and individuals including the County ofMendocino,

Caltrans, California Department of Forestry, California Coastal

Commission, local fire departments, the timber industry, City of

Point Arena, Manchester (Point Arena) Rancheria, and local

citizens, with the assistance ofthe U.S. Fish and Wildlife Service

and California Department ofFish and Game.

37
1.4 Enhance/restore habitat at existing populations. where appropriate.

Enhancement/restoration can increase the suitability and

availability of habitat for Point Arena mountain beaver. Guidelines

for enhancement and restoration of habitat should be determined

using data gathered in Task 4.7. Enhanced or restored habitat

should be monitored to assure that clearly identified standards of

success are met. The results of monitoring studies should be used

to identify adaptive management strategies to further enhancement

and restoration goals and objectives.

1 .4.1 Evaluate and identify protected sites for enhancement and

restoration

.

Priorities should include buffer habitat adjacent to existing

populations and degraded mountain beaver habitat with a

high degree of potential for success.

1.4.2 Develop and implement site-specific enhancement and

restoration strategies

.

A strategic plan should be developed for each

enhancement! restoration site outlining procedures, site

treatments, plant species selections, costs, timeline. and

success criteria. This plan should then be implemented at

each site.

1.4.3 Develop and implement vegetation monitoring plans for

enhanced/restored sites

.

Restoration sites must be monitored for a period oftime to

be determined under Task 5.2. Monitoring techniques

should be designed to contribute to our knowledge ofthe

habitat requirements of Point Arena mountain beaver.

Techniques should be selected from existing mitigation

38
guidance, expert input, and comparison with conditions at

other representative population and reference sites.

Sampling methodologies should be clearly defined. Goals

and success criteria should be developed for, but not

necessarily limited to, biological factors such as plant

species composition, survivorship, plant height, plant vigor

and health, percent vegetative cover, natural reproduction

and recruitment, and any physical factors found to be

representative of Point Arena mountain beaver habitat.

Contingency plans should be developed to guide remedial

actions in the event success criteria are not met. Population

trends ofthe mountain beaver, if present, should also be

monitored at restoration sites (see Task 1 .5).

1.5 Monitor existing Point Arena mountain beaver populations

.

A better understanding of population numbers and distribution will

give a fuller picture of population viability and threats to Point

Arena mountain beaver. These numbers are necessary to assess the

subspecies’ status over time. Techniques for monitoring should be

evaluated and developed (Task 4.3). All known populations

should be monitored to determine population trends and habitat

changes and identify threats to populations. To use available time

and funding most effectively, this monitoring should be both

qualitative and quantitative, with all populations being assessed

qualitatively, and only selected populations monitored using more

quantitative techniques.

1 .5.1 Develop protocols for qualitative and quantitative

monitoring

.

Protocols for the collection and analysis ofqualitative and

quantitative monitoring data should be developed using

39
information from Task 4.3.

1.5.2 Conduct qualitative assessments of all known populations

.

Each population should be monitored to determine its

status. Parameters to be noted include presence/absence of

burrows, activity (digging, clipping, debris, cobwebs, etc.).

habitat modification, disturbance, orthreats, and other

factors using protocols developed under Task 1.5.1.

Monitoring should be undertaken at the same time ofyear,

preferably in the spring or summer.

.5.3 Conduct quantitative assessments ofrepresentative

populations

.

Representative populations will be chosen to be monitored

in greater detail, using protocols identified under Task 1.5.1

and techniques developed in Task 4.3.

2. Survey to locate new populations

.

The historic range ofthe Point Arena mountain beaver should be surveyed

to identify any new populations. Much ofthe suitable mountain beaver

habitat, however, is on private land or in inaccessible areas. Therefore,

gaining access to these areas is essential to accomplishing this task. New

populations found beyond the current known range would be particularly

significant discoveries.

2.1 Develop a survey protocol

.

A presence-absence survey protocolshould be developed to guide

surveying efforts.

40
2.2 Identify suitable habitat for surveying.

The latest aerial mapping techniques should be used to identify

vegetation types known to provide suitable habitat for Point Arena

mountain beaver. Information gathered in Task 4.7 should assist in

identification ofsuitable habitat. Areas for surveying should

include class I and II streams to the east ofthe known range, as

well as stream drainages and other suitable habitat to the north and

south ofthe existing range. This mapping will help identify

buffers needed in Task 1.1, corridors between existing populations

(see Task 3). and/or other areas that may need special management

consideration.

2.3 Obtain permission from landowners to survey for Point Arena

mountain beaver

.

Before conducting surveys, the landowner must grant permission.

2.4 Survey suitable habitat for additional populations

.

Once permission to survey is obtained from landowners, surveys

should be conducted in suitable habitat identified in Task 2.2.

Also, the opportunity should be taken to collect Point Arena

mountain beaver data during other activities, such as Timber

Harvest Plan reviews, permitting. etc.

2.5 Update the California Natural Diversity Data Base (CNDDB)

.

To maintain a current and accurate database, all new population

information should be sent to the CNDDB for updating. When

making planning decisions, State and local agencies and private

entities rely on data from the CNDDB to identify areas that may

contain Point Arena mountain beaver. Agencies and individuals

do not always send new population findings to the CNDDB,

resulting in planning decisions based on outdated or insufficient

41
information on Point Arena mountain beaver.

2.6 Develop maps ofthe distribution ofthe Point Arena mountain

beaver

.

Maps of the distribution of Point Arena mountain beaver should be

developed using a Geographic Information System (GIS). Each

known population should be surveyed using Global Positioning

System (GPS) equipment to determine the precise location and

extent of burrow systems. These data could be combined with

monitoring data to quantify population sizes, habitat, and land uses

to accurately’ map the distribution ofthe subspecies. Mapping may

also help define a population as it relates to groups of burrow

systems. This term has been loosely applied to isolated burrows,

some of which likely have only one or two animals. Some

populations may actually be part of larger metapopulations. Using

information gained through mapping. along with genetic analysis

(Task 4.6), it should be possible to better define the population

structure of Point Arena mountain beaver.

3. Establish corridors between populations. where feasible

.

Corridors should be maintained or established, where feasible, to allow

movement and genetic exchange among populations. As more

iniornmtion becomes available on the distribution and habitat

requirements of Point Arena mountain beaver, it is expected that more

corridors will be identified.

3.1 Identify corridors needing protection

.

Using information gathered in Tasks 2.2, 2.4, and 4.7, identify

existing habitat that could provide corridors between mountain

beaver populations.

42
3.2. Protect identified corridors.

Corridors identified in Task 3.1 should be protected through

purchase, conservation easements or other appropriate mechanism.

Corridorsshould be monitored for mountain beaver activity (Task

1.5.2), and managed appropriately (Task 1.2 or 1.3). Habitat

within corridors should be enhanced/restored if deemed necessary

(Task 1.4.1).

4. Conduct research on Point Arena mountain beaver

.

More research is needed to determine what historic and current land use

activities favor or impact Point Arena mountain beaver populations. Also,

little information exists on the biology or ecology ofthe Point Arena

mountain beaver. Even anecdotal observations are scarce. Most of our

knowledge and assumptions are based on studies of other, more abundant,

subspecies of mountain beaver. To make informed management decisions

(i.e., applying adaptive management, which means conducting essential

research, analyzing the results, and revising management accordingly), it

is imperative to learn more about the Point Arena mountain beaver.

Researchers who have been studying mountain beaver in Washington

State and British Columbia have expressed interest in sharing information

and may be able to provide helpful insights and techniques for use with the

Point Arena subspecies.

4.1 Establish a library of literature on mountain beaver

.

A comprehensive library of mountain beaver and related literature

should be gathered and made available to researchers. This will

save time and facilitate research because some of the literature is

difficult to find. A literature search should be undertaken annually

to keep the library current.

43
4.2 Design studies to gather biological/ecological data on Point Arena

mountain beaver

.

When techniques are developed, design a study or series of studies

to collect data on parameters. Some of the basic parameters that

need to be determined include: density, dispersal, travel corridors,

population interconnectivity. age structure, litter size, longevity,

and sex ratio.

4.3 Develop safe and accurate monitoring techniques

.

Because mountain beaver spend most of their time underground, it

is difficult to gather certain data without capturing animals.

Indirect study methods should be used whenever feasible. Much of

the research on mountain beaver has been accomplished through

sacrificing animals. New techniques will need to be developed for

handling animals with minimum disturbance and risk. A review of

the literature to find successful surveying techniques used with

similar animals would supplement this effort. All techniques must

be perfected using other subspecies of mountain beaver before

being attempted on Point Arena mountain beaver. The Point Reyes

mountain beaver is most similar to the Point Arena mountain

beaver and, therefore, would be the subspecies of choice for this

work. The October 1995 fire at Point Reyes National Seashore

resulted in monitoring ofthe surviving Point Reyes mountain

beaver population. Monitoring there involves transect surveys of

burrows to determine the beaver’s survival and distribution within

the burn area, and ~~automated”monitoring of burrows to determine

short-term survival, reproductive success, and habitat suitability

(BAER Team 1995). Many of these techniques could be used for

the Point Arena mountain beaver.

Monitoring ofthe Point Arena mountain beaver was also done for

the MCI Telecommunications Corporation. Method descriptions

44
can be found in Northen and Fitts (1993-1996, 1998). These

methods may be suitable for use in future Point Arena mountain

beaver monitoring activities.

4.3.1 Develop indirect monitoring techniques

.

Indirect techniques, including cameras, smoke plates,

microphones, activity counters, trip wires, hair traps and

others, are preferable since they involve the least

disturbance to the animals. These techniques need to be

evaluated to determine which are most effective.

4.3.2 Develop safe live-trapping/handling techniques

.

Mountain beaver are known to suffer from high trap

mortality, at least in the Pacific Northwest (Dodge and

Campbell 1965). Methods to minimize danger to the

animal (and to the handler) must be perfected using other

subspecies, prior to conducting any extensive live-trapping

ofthe Point Arena mountain beaver.

4.3.3 Develop and implement safe radiotelemetry techniques

.

Certain types ofinformation, such as movement and

dispersal activity, and home range, can only be gathered

by following individuals through time. Radiotelemetry is

an effective way of doing this. This technique should be

adapted to Point Arena mountain beaver, again being

perfected on a more abundant subspecies.

4.4 Study effects ofscent on population establishment and dispersal

.

Pheromone analysis may help determine whether chemical cues are

causing Point Arena mountain beaver to cluster and occupy some

45
habitat and not to occupy other seemingly appropriate habitat.

4.5 Study effects of disturbance

.

The Point Arena mountain beaver’s sensitivity to disturbance is

largely unknown. There have been several recent questions about

disturbances of various kinds and the appropriate buffer zones

needed to protect animals. More work needs to be done in these

areas. Disturbance needs to be evaluated, including the effects of

electromagnetic fields, noise, vibration, toxins, microwaves, and

habitat modification, including fire. timber harvesting, and

invasion of exotic plants such as German ivy, ice plant, and

European beach grass. The ability of buffers to minimize

disturbances should be evaluated. Results of this task should be

used to update the comprehensive guidelines prepared in Task 1.3.

4.6 Conduct genetic analysis

.

It is generally accepted that Point Arena mountain beaver has been

geographically isolated from other subspecies for a long time. but

the length and degree of genetic isolation are unknown. insights

could be provided through genetic analysis and comparison ~vith

other subspecies. It may be that full species status is more

appropriate, as originally believed by Taylor (1914). This task is

not considered to be of sufficient priority to warrant sacrificing

animals. Material appropriate for genetic analysis should be

salvaged, as appropriate, from animals that have died due to other

causes, according to the necropsy/salvage protocol developed in

Task 4.10. Also, hair, tissue, and blood samples could be collected

from live animals.

4.7 Determine habitat requirements for Point Arena mountain beaver

.

There is little quantitative information on the habitat requirements

46
of Point Arena mountain beaver. Populations have been found in a

variety of habitat types, but basic limiting factors are not known.

This information is necessary for management purposes and

possible habitat restoration work.

Data should be collected on the following habitat parameters:

vegetation associations (including exotic plants) and cover values,

soil characteristics, slope/aspect, microclimate, hydrology, etc.

Studies should be done on the spectrum of mountain beaver

habitats. Historic aerial photos and mapping can be used to

compare previous vegetation and land uses with current habitat

use.

The duration and methodologies ofthis research should be

determined under Task 4.2. It may be best to collect data over a

longer period oftime if unusual conditions such as drought occur.

4.8 Study the relationship of Point Arena mountain beaver to

successional habitat

.

The importance ofsuccessional habitat to Point Arena mountain

beavers needs to be investigated at several sites where mountain

beaver populations are found near recent timber harvesting

activities.

4.9 Study food habits

.

While it is known that Point Arena mountain beaver utilize many,

if not most. ofthe plant species in their vicinity, there is little

information on which plants are most important in their diet. A

fecal analysis study could help to determine important food plants.

Fecal material should be gathered over time, because food

preferences may change throughout the year. Stomach contents

from fresh carcasses can also be analyzed, according to the

47
protocol developed in Task 4.10.

4.10 Develop protocol for necropsies on any acquired carcass

.

A protocol must be developed for treating animals found dead, to

maximize the information available on the Point Arena mountain

beaver. This protocol should include procedures for handling dead

animals, salvaging and storing parts for further study, identifying

the responsible party, data collection and analysis, necropsy

procedures, museum or other repository consignment, and

reporting ofresults.

4. 11 Conduct a population viability analysis (PVA)

.

Conduct a PVA assessment using information gathered from Task

4.2. The PVA results should be used to assess the adequacy ofthe

criteria for downlisting. delisting, and population stability, if

possible.

4.12 Develop indicesto track the active number ofPoint Arena

mountain beaver burrows

.

Indices should be developed to keep track ofall active Point Arena

mountain beaver burrows.

5. Restore the Point Arena mountain beaver to suitable habitat

.

Restoration of Point Arena mountain beavers to suitable habitat may be a

necessary tool for recovery ifadditional populations are not found to meet

recovery criteria. The feasibility and necessity ofrelocating animals,

however, should be evaluated after basic information is gathered about

Point Arena mountain beaver and its habitat requirements.

48
5.1 Determine feasibility and necessity ofrelocation.

The feasibility and necessity of relocation should be assessed

based on all available information.

5.2 Develop relocation protocols and conduct relocations, if feasible

and necessary

.

Ifrelocation is deemed appropriate and necessary, a plan should be

developed that identifies suitable habitat for relocation activities,

appropriate animals to be relocated (e.g., dispersing juveniles), and

practical/technical aspects ofthe relocation project. Relocations

would likely be conducted over several years. Relocated

populations should be protected (Task 1.1); management plans

should be developed and implemented, that include a contingency

plan in the event that success criteria are not met (Task 1.2); and

populations should be monitored (Task 1.5).

6. Conduct outreach

.

To enlist the long-term support oflandowners with Point Arena mountain

beaver populations, the U.S. Fish and Wildlife Service, with assistance

from the California Department ofFish and Game, should work one-onone with each landowner to develop a program to protect the beaver and

its habitat.

6.1 Develop and implement an outreach plan

.

Outreach is an essential component ofimplementing this plan. A

plan should be developed to provide factual information about the

Point Arena mountain beaver and the recovery process to

interested and effected landowners. For private lands with reported

populations ofthe Point Arena mountain beaver, landowners

should be apprised ofthe significance ofthe populations on their

49
lands and should be provided with information about available

conservation mechanisms, such as conservation easements and

incentive programs. For private lands with suitable habitat for

Point Arena mountain beaver, permission should be sought from

cooperative landowners to conduct on-site surveys (Task 2.4). If

surveys identify populations, landowners should be apprised of

their significance and offered incentives to continue current land

uses that support mountain beaver habitat.

6.1.1 Develop and implement economic or other incentives for

conservation and recovery ofthe Point Arena mountain

beaver

.

Economic and other incentive programs (e.g., relief from

taxes, tax credits, tax deductible habitat management

expenses, Williamson Act. Conservation Reserve

Program, Partners for Wildlife, etc.) may be important to

gaining the support and assistance ofprivate landowners

in conserving and recovering the Point Arena mountain

beaver. Such programs, if appropriate, should be

developed for the planning area. Incentive programs could

play an important role in protection of habitat on private

property.

6. 1 .2 Produce and disseminate outreach materials

.

A comprehensive outreach program could include the

following materials:

o A booklet for adults that presents information on the

biological importance ofthe Point Arena mountain

beaver.

0 A separate brochure to inform landowners ofresources

50
available to them and steps they can take to protect

mountain beaver on their land.

o An activity/educational book for children, geared for

ages 6 to 12. This booklet could be disseminated

through schools, at Manchester Beach State Park,

through agency offices, etc.

o Other interpretive materials, such as models, are an

important part of any outreach effort. The possibility

of a permanent display should be explored.

o Periodic press releases on the recovery effort for

dissemination to the media.

o Selected materials from this effort should be made

available on the Internet and possibly in an electronic

form, such as a compact disc, which can be used for

educational purposes.

51
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Natural Resources Conservation Service, Petaluma District.

Beier, P. 1989. Use ofhabitat by mountain beaver in the Sierra Nevada. Journal

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Cafferata, S.L. 1992. Chapter II, Mountain Beaver. In Silvicultural approaches

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Campbell, D. and J. Evans. 1989. Aversive conditioning with thiram to reduce

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Canaris. A. and D. Bowers. 1992. Metazoan parasites ofthe mountain beaver,

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Carey, M., D. Campbell, and C. Campbell. Physical structure, flora and fauna of

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Cramblet, H. and R. Ridenhour. 1956. Parturition in Aplodontia. Journal of

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Crouch, G. 1968. Clipping ofwoody plants by mountain beaver. Journal of

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Dalquest, W. and V. Scheffer. 1945. The systematic status ofthe races ofthe

mountain beaver (Aplodontia rufa) in Washington. Murrelet 26(3):34—37.

Davis, J. 1941. Notes on a captive mountain beaver. Murrelet 22(3):60—61.

Dicker, S. and M. Eggleton. 1964. Renal function in the primitive mammal

Aplodontia rufa with some observations on squirrels. Journal ofPhysiology

170:186—194.

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Dolph, C., H. Braun, and E. Pfeiffer. 1962. The effect of vasopressin upon urine

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Finley, Jr., R. 1941. Geographic variation in the rodent Aplodontia rufa.

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Fisler, G. 1965. A captive mountain beaver. Journal ofMammalogy

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Fitts, K. 1996. Observations on use oftwo non-native plants by the Point Arena

mountain beaver. California Fish and Game 82(l):59-60.

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ME. Sould and B.A. Wilcox, eds. Conservation biology, an evolutionaryecological perspective. Sinauer Assoc., Sunderland, Mass.

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Thesis. Humboldt State College, Arcata, CA.

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Environment.

Hacker. A. and B. Coblentz. 1993. Habitat selection by mountain beavers

recolonizing Oregon coast range clearcuts. Journal of Wildlife Management

57(4):847—853.

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Wiley and Sons. New York NY.

Hall. E. and K. Kelson. 1959. The mammals of North America. Ronald Press

Co. New York. Vol. 1, p. 290—292.

Herlocker, F. 1950. Mountain beaver-biological curiosity. Audubon Magazine

54
3 87—3 90.

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Forestry, Oregon State University. pp. 75-97.

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Ingles. E. 1960. Underground dwellersin the forest. Audubon Magazine

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55
and Wildlife Service Report W-84-R-7 IL-S.

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57
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59
endangered. 56(239): 64716-64722.

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D. PERSONAL COMMUNICATIONS

Fellers, G. 1996. Biological Resources Division, U.S. Geological Survey, Point

Reycs National Seashore. Point Reyes, California.

Fitts, K. 1 994. Wildlife Biologist. Santa Rosa, California.

Fuller. K. 1996. Botanist. U.S. Fish and Wildlife Service. Sacramento,

California.

Heffner, R.. PhD. 1994. University of Toledo, Department of Psychology.

Toledo, Ohio.

Joe, K. 1989. Park Ranger. California Department ofParks and Recreation,

Manchester Beach State Park. Mendocino, California.

60
Mohr, A. 1996. Alan Mohr and Associates, Inc. Point Arena, California.

Ramos, E. 1994. California Department of Fish and Game. Yountville,

California.

Steele, D. 1992, 1994, 1998. Ecologist - Mountain Beaver Research. Stockton,

California.

Wooster, T. 1992. 1997. California Department of Fish and Game. Yountville,

California.

E. INLITT. REFERENCES

Flowers, 5. 1997. Letter to Wayne S. White, U.S. Fish and Wildlife Service,

Sacramento, CA, commenting on Draft Point Arena Mountain Beaver

Recovery Plan.

Levine, A. 1997. Letter to Wayne S. White, U.S. Fish and Wildlife Service,

Sacramento, CA, commenting on Draft Point Arena Mountain Beaver

Recovery Plan.

Valentine, B. 1997. Letter to Wayne S. White, U.S. Fish and Wildlife Service,

Sacramento, CA, commenting on Draft Point Arena Mountain Beaver

Recovery Plan.

Wooster, T. 1997. Letter to Wayne S. White, U.S. Fish and Wildlife Service,

Sacramento, CA, commenting on Draft Point Arena Mountain Beaver

Recovery Plan.

61
III. Implementation Schedule

The Implementation Schedule that follows outlines actions and estimated costs for

the recovery program ofAplodontia rufa nigra. It is a guide for meeting the

objectives discussed in Part II ofthis Plan. This schedule indicates task priorities,

task numbers, task descriptions, duration oftasks, the responsible agencies. and

estimated costs. These actions, when accomplished, should bring about the

recovery ofthe species and protect its habitat. Cost estimates provided here are

intended as gross estimates for general planning purposes. More detailed budget

analyses will be necessary by the responsible agencies.

Definition of Priorities:

An action that must be taken to prevent extinction or to prevent the

species from declining irreversibly in the foreseeable future.

An action that must be taken to prevent a significant decline in

species populationlhabitat quality, or some other significant

negative impact short ofextinction.

All other actions necess:Ary to meet the recovery objectives.

Task Duration:

Continuous: A task that will be implemented on a routine basis once begun.

Unknown: Either task duration or associated costs are not known at this time.

Priority 1:

Priority 2:

Priority 3:

62
Acronyms and Abbreviations:

CDF - California Department ofForestry and Fire Protection

CDFG - California Department ofFish and Game

CDPR - California Department ofParks and Recreation

CNDDB - California Natural Diversity Database

COUN - County of Mendocino

EWS - U.S. Fish and Wildlife Service

TBD - To Be Determined

63
Implementation Schedule for the Point Arena Mountain Beaver

V

Vr~ortty

—

I

T

T~k

—

I I

Task fl~tration

(Yrs.)

R~pons~bk

Pjtrty

Total

—CGst

5000

Ii~ $1,QI~

——— —FY1~ —FY2 —EY3 ——FY4 —FYS

Protcct existing 1000 1000 1000 1000

populations

FWS. CDFG

(DPR

1 2 Dexelop and implement

management plans

continuous EWS. (‘DF(i

C[)PR

50 0 3 0 3 0 3 0 3 0 3 0

2 13 Develop and implement

management guidelines

continuous FWS. CDFG

CI)PR. COIJN

CDF. others

50 0 3 0 3 0 3 0 3 0 3 0

2 1 4 I Identif\ habitat for

restoration

2 I

7WS. CDFG ~ 0 2 5 2 5

2 1.4.2 Dexelop and implement

site-specific restoration

strategies

1 VWS, CDFG TBD TBD

2 1.4.3 Monitorrestoration 5 FWS 20.0 4.0

2 1.5,1 Develop monitoring

protocol

I EWS. CDFG 3.0 3.0

2 1 5 2 Conduct qualitative

monitoring of populations

continuous EWS, (‘DF(i 25 0 2 5 ) 5 2 5 2 5 2 5

2 153 Conduct quantitative

monitoring of populations

5 EWS. CDFG 100 20 20 20 20

2 2 1 Develop a survey protocol I EWS. CI)FG 5 1) a

2 2 2 Identify suitable habitat

forsurveying

I FWS. CDFG 5 0 a 0
—

Implementation Schedule for the Point Arena Mountain Beaver — fl...-.*trnt Rp~nftn~ih1I. Total C4~*s in $E~.. C*mnen~

2

2

2

2 3

fle~rriptkn (Yrs) 9 P~irty (rust

—

2 0

— —

FYI

———1 rvz FY~

2 0

F

——FY4 FY —

Obtain landowner’s

permission to survey

I FWS, CDFG

2 2 4 Survey for additional

populations

3 FWS, CDFG,

CDF

15 0 5 t) 5 0 5 0

2 3 1 Identify corridors to

protect

5 l’WS, CDFG 00

2 3 2 Protect identified

corridors

unknown FWS TBD

2 4 2 Design studies to gather

biological! ecological data

2 FWS, CDFG TBD

2 4.3.1 Develop indirect

monitoring techniques

4 EWS, CDFG 50.0 20.0 10.0 10.0 10.0

2 4.3.2 Develop safe livetrapping/handling

techniques

2 FWS 20.0 10.0 10.0

2 4.3.3 Develop radiotelemetry

studies

4 FWS 50.0 20.0 10.0 10.0

2 4.4 Study effects of scent 2 FWS TBD

2 4.5 Studx’ effects of

disturbance

5 FWS 60.0 20.0 10.0 10.0 10.0

2 4.7 Determine habitat

requirements

5 FWS. CDFG 60.0 20.0 10.0 10.0 10.0

Cx
Implementation Schedule for the Point Arena Mountain Beaver P

Priority

—

2

T

Task

N —

4 9

Task

Description

D

DfIr~Itiftn

(Vi’s)

Responsible

Party

T

Total

Csst —

Costs in $1,604) Comments

FYI’ EYZ FY3 FY4 FY5 —

Study Ibod habits 2 l’W’~

3 2.5 Update (‘NDDB continuous (‘l)EG 0.0

3 2.6 [)evelop (ilS map continuous I \\ S. CDF(i (10

3 4.1 Establish library continuous FWS 0.0

3 4.6 Conduct genetic amilx 5es V\VS 20.0

10.0 10.0

3 4 8 Study relationship of

successional habitat

IWS. (l)FG 50 0 10.0 10.0 10.0 10.0

3 4.10 Develop protocol for

necropsies

I l\VS 2 0 2.0

3 4.11 Conduct population

viability anal’,ses

I FWS. CDi(j 10 0

3 5.1 Determine feasibilit’, of

relocation

I FWS 0.0

3 5.2 Plan and conduct

relocations

iffeasible

and needed

IV’ 5 1131)

3 6.1.1 Develop and implement

incentives for recover’,’

continuous FWS. CDFG TBD

3 6 1 2 Produce outreach

materials

I FW~.CL)PR 15 0 15 0

‘FYI designates the first fiscal year following approval ofthe Recovery Plan.
IV. Appendix A: Summary ofthe Agency and Public Comments

on the Draft Recovery Plan for the Point Arena

Mountain Beaver

I.Summary of Comments

In July 1997, the Service released the Draft Recovery Plan for the Point

Arena Mountain Beaver (Draft Plan) for a 60-day comment period ending

on October 20, 1997 for Federal agencies, State and local governments,

and members of the public (62 FR 4413). Dr. Paul Beier, jAr. Gordon

Gould, and Mr. John Harris were requested to peer review the Draft Plan.

This section summarizes the content of significant comments on the Draft

Plan. A total of 11 letters were received, each containing varying numbers

of comments. Many specific comments re-occurred in letters.

This section provides a summary of general demographic information,

including the total number of letters received from various affiliations and

states. It also provides a summary’ of the eight major comments. A

complete index ofthe commenters, by affiliation, is given in the Section

B. All letters of comment on the Draft Plan are kept on file in the Arcata

Fish and Wildlife Office.

A. Demographic Information

The following is a breakdown ofthe number of letters received from

various affiliations:

State agencies 4 letters

local governments 2 letters

business and industry I letter

environmental/conservation organizations 3 letters

academia/professional 1 letter

67
B. Reviewers ofthe Draft Recovery Plan

Dahlhoff, Leslie, City ofPoint Arena, 451 School Street, P.O. Box 67,

Point Arena, CA 95468

Fellers, Gary, U.S. Department ofthe Interior, U.S. Geological Survey,

Biological Resources Division, Point Reyes National Seashore, Point

Reyes, CA 94956

FiUs, Kimberley, 5243 Beaumont Way, Santa Rosa, CA 95409

Flowers, Sarah, Department of Parks and Recreation, Russian

River/Mendocino District, P.O. Box 440, Mendocino, CA 95460

Gould, Gordon, California Department ofFish and Game, 1416 Ninth

Street, P.O. Box 944209, Sacramento, CA 94244

Griffin, Jenny, Jenny Griffin Landscaping, P.O. Box 1503, Mendocino,

CA 95460

Hodgson, Ann, Resource Designs, Inc., 1349 5. 101 Street, Suite

304,Omaha, NE 68124

Levine, Alan, Coast Action Group, P.O. Box 215, Point Arena, CA 95468

Northen, Philip, Sonoma State University, School ofNatural Resources,

1801 East Cotati Avenue, Rhonert Park, CA 94928

Valentine, Bradley, California Department of Forestry and Fire Protection,

Coast-Cascade Region, P.O. Box 670, 135 Ridgway Avenue, Santa

Rosa, CA 95402

Wooster, Theodore, California Department ofFish and Game, P.O. Box

47, Yountville, CA 94599

68
II. Summary of Comments and Service Responses

Issue 1: A number ofcomments were received that contained requests to

include additional information such as updated population locations ofthe

Point Arena mountain beaver, additional species of concern, etc.

Response: This new information has been incorporated into the Final

Plan.

Issue 2: More surveys need to be done to establish locations of other, new

Point Arena mountain beaver populations.

Response: Please see the ~StepdownNarrative”, Task 2.0 ofthe Final

Plan, which is “Survey to locate new populations”.

Issue 3: There is little quantitative support and explanation for, and

possibly attainability of, the recovery criteria (downlisting and delisting).

Also, for #1, #2 and #3 ofthe downlisting and delisting criteria, why are

the existing populations found along the creeks listed, singled out as being

the main populations to be protected?

Response: Recovery criteria have been revised to better reflect existing

information based on best knowledge of existing conditions. These

criteria may be further revised when new information becomes available.

Reference to specific existing populations found along creeks has been

deleted from the recovery criteria.

Issue 4: The discussion on “Reasons for Listing and Threats to Survival”

contains no substantiation on importance, no plan to address the threats, no

determination ofimportance, and some threats cannot be planned for and

are not as catastrophic as suggested.

Response: This section has been revised to better reflect importance of

threats and substantiation ofthreats. Also, some threats which “cannot be

69
planned for” (e.g., fire), were eliminated from the text. Threats are also

discussed in the “Stepdown Narrative” under Task 1.2.

Issue 5: A broad-scale effort should be undertaken to solicit the opinions

ofthe public regarding their perceptions about mountain beavers as pests.

Flexible solicitation ofpublic opinions and ongoing public forums to

involve and educate the public about the management concerns related to

this species is necessary. The Draft Plan proposes an outreach effort

which would include the productions and dissemination of educational

materials, but may not effectively invoke “ownership” and broad-scale

participation by the community.

Response: In the “Stepdown Narrative”, Task 6.0, we have elaborated on

this issue.

Issue 6: The Draft Plan reflects a general literature review for the species

as a whole, with little regard to the fact that the Point Arena mountain

beaver lives in somewhat unusual habitat and in an unusual setting.

Response: The “Habitat” section has been modified to better reflect the

literature specifically available on the Point Arena mountain beaver versus

other subspecies ofmountain beaver.

Issue 7: Elevate task “Survey along drainages for limits of Point Arena

mountain beaver” to top priority level.

Response: The U.S. Fish and Wildlife Service cannot consider surveys as

Priority 1 tasks (see “Definition of Priorities” given in Section III ofthe

Final Plan). Alone, this task would not prevent the extinction ofthe

species.

Issue 8: At this time, the City of Point Arena and landowners need

specific management guidelines from the U.S. Fish and Wildlife Service

concerning the Point Arena mountain beaver. A review of Section 5.24 of

70
the City’s Zoning Ordinance, which explains the Mountain Beaver Buffer

Area (MBBA), and the special rules that apply to it, need to be reviewed

by the U.S. Fish and Wildlife Service for accuracy ofthe statements

regarding the Federal Endangered Species Act and protection measures.

Response: The Sacramento Fish and Wildlife Office has forwarded a

copy ofthe City~s Zoning Ordinance, with specific questions from the

City of Point Arena about this proposed Ordinance, to the Arcata Fish and

Wildlife Office. Due to the location of Fish and Wildlife Offices in the

state, and a change in Ecoregion organization since the Recovery Plan for

the species was begun, the Arcata Fish and Wildlife Office now has

primary responsibility for the Point Arena mountain beaver.

71
Region 1

U.S. Fish and Wildlife Service

Ecological Services

911 N.E. 11th Avenue

Portland, Oregon 97232-4181

U

June 1998