Federal Register / Vol. 65, No. 198 / Thursday, October 12, 2000 / Proposed Rules 60603

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife

and Plants: 90-Day Finding on a

Petition To List the Mountain Yellowlegged Frog as Endangered

AGENCY: Fish and Wildlife Service,

Interior.

ACTION: Notice of 90-day petition

finding.

SUMMARY: The U.S. Fish and Wildlife

Service (Service) announces a 90-day

finding on a petition to list the

mountain yellow-legged frog (Rana

muscosa) as endangered, under the

Endangered Species Act (Act) of 1973,

as amended (16 U.S.C. 1531 et seq.). We

believe that the petition presents

substantial information indicating that

listing the species may be warranted. A

status review is initiated.

DATES: The finding announced in this

document was made on October 5, 2000.

To be considered in the 12-month

finding for this petition, comments and

information should be submitted to the

Service by December 11, 2000.

ADDRESSES: Data, information,

comments, or questions concerning this

petition should be submitted to the

Field Supervisor; Sacramento Fish and

Wildlife Office; Sacramento Fish and

Wildlife Office; 2800 Cottage Way,

Room W–2605; Sacramento, California

95825. The petition finding, supporting

data and comments are available for

public inspection, by appointment,

during normal business hours at the

above address.

FOR FURTHER INFORMATION CONTACT:

Jason Davis or Maria Boroja at the

Sacramento Fish and Wildlife Office

(see ADDRESSES section above), or at

(916) 414–6600.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(A) of the Endangered

Species Act (Act) of 1973, as amended

(16 U.S.C. 1531 et seq.), requires that the

Service make a finding on whether a

petition to list, delist, or reclassify a

species presents substantial information

indicating that the petitioned action

may be warranted. To the maximum

extent practicable, this finding is to be

made within 90 days of the receipt of

the petition, and the finding is to be

published promptly in the Federal

Register. If the finding is that

substantial information was presented,

the Service will commence a review of

the status of the involved species. This

finding is based on information

contained in the petition, supporting

information submitted with the petition,

and otherwise available to the Service at

the time the finding was made.

The processing of this petition

conforms with our final listing priority

guidance published in the Federal

Register on October 22, 1999 (64 FR

57114). The guidance clarifies the order

in which we will process rulemakings.

Highest priority is processing

emergency listing rules for any species

determined to face a significant and

imminent risk to its well-being (Priority

1). Second priority (Priority 2) is

processing final determinations on

proposed additions to the lists of

endangered and threatened wildlife and

plants. Third priority (Priority 3) is

processing new proposals to add species

to the lists. The processing of

administrative petition findings

(petitions filed under section 4 of the

Act) is the fourth priority. The

processing of critical habitat

determinations (prudency and

determinability decisions) and proposed

or final designations of critical habitat

will be funded separately from other

section 4 listing actions and will no

longer be subject to prioritization under

the listing priority guidance. The

processing of this petition finding is a

Priority 4 action.

We have made a 90-day finding on a

petition to list the mountain yellowlegged frog (Rana muscosa) as an

endangered species. On February 10,

2000, we received a petition, dated

February 8, 2000, to list the Sierra

Nevada Mountain population of the

mountain yellow-legged frog as an

endangered species. The petition was

submitted by the Center for Biological

Diversity and Pacific Rivers Council.

The letter clearly identified itself as a

petition, and contained the names,

signatures, and addresses of the two

parties submitting the petition. The

petitioners argued that the ‘‘Sierra

Nevada population of the mountain

yellow-legged frog’’ qualifies for listing

under our Distinct Vertebrate

Population Segment Policy (61 FR

4722). Included in the petition was

supporting information relating to the

species’ taxonomy and ecology,

adequacy of existing regulatory

mechanisms for the species, and the

historic and present distribution,

current status, and potential causes of

decline. This notice constitutes the 90-

day finding for the February 10, 2000,

petition.

On July 10, 1995, we were petitioned

to list the southern California

population of the mountain yellowlegged frog a distinct population

segment (DPS) of the mountain yellowlegged frog. The southern California

population is isolated from the main

part of the species’ range, in the Sierra

Nevada Mountains, by the Tehachapi

Mountains and a distance of 225

kilometers (km) (140 miles(mi)). On

December 22, 1999, we published a

proposed rule to list the Southern

California DPS of the mountain yellowlegged frog as an endangered species (64

FR 71714). In the proposed rule we

recognized the southern population

according to our policy on distinct

vertebrate population segments (61 FR

4722). On March 20, 2000, we published

a notice in the Federal Register to

reopen the comment period on the

proposal to list the southern California

DPS of the mountain yellow-legged frog

as endangered for a 30-day period.

As the present petition (and this

finding) addresses the remainder of the

species’ range, in the Sierra Nevada

from Tulare County, California, in the

south to Plumas County, California, in

the north, we find no reason to

recognize mountain yellow-legged frogs

that occur in the Sierra Nevada as a

DPS. Throughout the rest of this finding

we refer to the petitioned entity, all

mountain yellow-legged frogs that occur

north of the Tehachapi Mountains in the

Sierra Nevada, as the mountain yellowlegged frog.

The petition and accompanying

documentation state that the species

qualifies for listing pursuant to the Act

due to potential habitat destruction and

modification, the presence of disease in

combination with natural predation, the

inadequacy of existing regulatory

mechanisms, and other natural or

human-caused factors affecting its

continued existence. The petitioners

contend that natural and humaninduced changes to mountain yellowlegged frog habitats, including (1) nonnative fish introductions, (2)

contaminant introductions, (3) livestock

grazing, (4) acidification from

atmospheric deposition, (5) nitrate

deposition, (6) ultraviolet radiation, (7)

drought, and (8) other factors, separately

and in combination are responsible for

an estimated 70 to 90 percent decline in

mountain yellow-legged frog

populations throughout the historic

range of the species in the Sierra Nevada

Mountains.

The introduction of nonnative fish,

including rainbow trout (Oncorhynchus

mykiss), is one the best documented

causes of decline of Sierra Nevada

Mountain populations of mountain

yellow-legged frogs. Careful study of the

distributions of introduced trout and

mountain yellow-legged frogs for several

years has shown conclusively that

60604 Federal Register / Vol. 65, No. 198 / Thursday, October 12, 2000 / Proposed Rules

introduced trout have had negative

impacts on mountain yellow-legged

frogs over much of the Sierra Nevada

Mountains (Bradford 1989; Knapp

1996). Bradford (1989) and Bradford et

al. (1994) concluded that introduced

trout have eliminated many populations

of mountain yellow-legged frogs. In

addition, the presence of trout in

intervening streams sufficiently isolates

other frog populations so recolonization

after stochastic (random, naturally

occurring) local extinctions is

essentially impossible. This mechanism

is sufficient to explain the elimination

of mountain yellow-legged frogs from

the majority of sites they once inhabited

in the Sierra Nevada Mountains.

Several studies have shown that

significant levels of contaminants have

been deposited in high Sierran aquatic

ecosystems from pesticide drift, acid

precipitation, and smog drift (Seiber et

al. 1998; Aston and Seiber 1997; Cahill

et al. 1996; Miller 1996; Byron and

Goldman 1991; Nikolaidis 1991; Laird et

al. 1986). The petitioners present

general evidence that the presence of

contaminants in water, sediment, and

aquatic vegetation can harm frog

populations through lethal and

sublethal effects including delayed

metamorphosis, reduced breeding and

feeding activity (Berrill et al. 1993,

1994, 1995, 1998; Boyer and Grue 1995;

Beaties and Tyler-Jones 1992; Corn and

Vertucci 1992; Hall and Henry 1992). In

addition, contaminant introduction may

weaken the immune systems of frogs

rendering them more susceptible to

disease such as chytrid fungus and redlegged disease (Carey et al. 1993, 1995,

1999; Jennings 1996; Drost and Fellers

1996; Sherman and Morton 1993). The

petitioners cite recent work by Carlos

Davidson (U.C. Davis, unpublished

manuscript) that shows a positive

relationship between amphibian

declines in the Sierra Nevada

Mountains that occur upwind from

areas in California’s Central Valley that

apply large amounts of wind-borne

agrochemicals. In particular, Davidson

found agricultural land use to be twice

as high downwind of sites where

mountain yellow-legged frogs had

disappeared compared to sites where

the species is still present (Davidson,

unpublished manuscript).

Livestock grazing can directly impact

mountain yellow-legged frogs through

trampling of individuals. Indirectly,

livestock can have a significant effect on

frog populations by: (1) Altering the

hydrology and morphology of high

mountain streams and ponds, (2)

trampling of cover and vegetation along

the periphery of wetland systems that

are important egg laying and larval

rearing areas, and (3) introducing

nitrates into breeding areas resulting in

elevated levels of bacteria (Armour et al.

1994; Duff 1977; Bohn and Buckhouse

1985; Kauffman and Krueger 1984;

Kauffman et al. 1983; Marlow and

Pogacnik 1985; Meehan and Platts 1978;

Stephenson and Street 1978; U.S. Forest

Service 2000).

Acidification, nitrate deposition, and

ultraviolet radiation have been

implicated as other factors that may

contribute to the range wide decline of

mountain yellow-legged frogs. The

petitioners state these factors may have

negative effects on mountain yellowlegged frogs that include reduced

growth rates, reduced feeding activity,

disequilibrium, physical abnormalities,

paralysis, embryonic failure, and even

death among tadpoles and young frogs

(Blaustein et al. 1994, Bradford and

Gordon 1993, Carey et al. 1999, Clark

and LaZerte 1985, Freda 1990, Marco et

al. 1999, Marco and Blaustein 1999).

During periods of prolonged drought,

amphibians find refugial habitat in

deeper, permanent sources of water

which are also suited for fish. These

refugial habitats allow for repopulation

of more peripheral areas during wetter

years (Bradford et al. 1993; Knapp 1996;

Drost and Fellers 1996). The presence of

nonnative fish has eliminated many of

the permanent sources of refugial

habitat from the mountain yellowlegged frog, thus rendering frog

populations more vulnerable to droughtrelated extinction events (Bradford et al.

1993; Knapp 1996; Drost and Fellers

1996).

The petitioners state that disease

likely plays a significant role in the

widespread decline of mountain yellowlegged frogs. Two diseases potentially

affecting mountain yellow-legged frogs

are red-legged disease (Aeromonas

hydrophila), which is caused by a

freshwater bacteria, and chytrid fungus.

The petitioners cite an article by

Bradford (1991) reporting the loss of a

mountain yellow-legged frog population

in the Sierra Nevada due to red-legged

frog disease and predation by Brewer’s

blackbirds (Euphagus cyanocephalus).

In addition, they cite studies reporting

mortality of adult Yosemite toads (Bufo

canorus) in the Sierra Nevada and

boreal toads (Bufo boreas boreas) in the

Rocky Mountains due to red-legged

disease (Sherman and Morton 1993;

Carey 1993). Chytrid fungus, an aquatic

pathogen discovered after 1993, has led

to the mortality of many amphibian

species in the United States and

worldwide. The chytrid fungus attacks

the mouthparts of tadpoles affecting

their ability to feed. Chytrids have

recently been discovered in larval

mountain yellow-legged frogs in the

Sierra Nevada (Gary Fellers, U.S.

Geologic Survey, pers. comm. 1999).

Roland Knapp (Sierra Nevada Aquatic

Research Lab, pers. comm. 2000)

reported a significant decline of

mountain yellow-legged frogs at Dry

Creek near Mono Lake, a site that had

thriving population in 1998. He

attributed the population crash to the

chytrid fungus after detecting deformed

mouthparts in several tadpoles at the

site. The petitioners also cite a personal

communication with Vance Vredenburg

(University of California, Berkeley,

Museum of Vertebrate Zoology, pers.

comm. 2000) who reported the complete

loss of another mountain yellow-legged

frog population in the Emigrant

Wilderness due to the chytrid fungus.

There have been reports of chytrid

fungus attacking other Sierra Nevada

amphibians, including the Yosemite

toad. An investigation of museum

specimens of Yosemite toads collected

by Sherman and Morton at Tioga Pass

during a 1977–1978 die-off found those

toads to be infected with chytrid fungus

(Carey et al. 1999). The petitioners state

that there is significant information yet

to be discovered regarding aquatic

pathogens and their relationship to the

ecology of mountain yellow-legged

frogs. Should evidence indicate that

mountain yellow-legged frogs have

evolved with aquatic pathogens, then

other stressors including contaminant

introductions and UV-radiation may be

reducing the ability of frogs to fight off

infection from these pathogens

(Sherman and Morton 1993; Drost and

Fellers 1996; Carey et al. 1993, 1995,

1999; Jennings 1996; Taylor et al. 1999).

Up to the 1960s, the mountain yellowlegged frog was widely distributed and

abundant across the Sierra Nevada

(Zwefel 1955; Cory et al. 1970, Jennings

and Hayes 1994). Since then, however,

the overall population has declined

dramatically. The most pronounced

declines have occurred within the

northernmost 125 km (78 mi) of the

range, north of Lake Tahoe, and the

southernmost 50 km (31 mi) of the

range, below Sequoia and Kings Canyon

National Parks, where only a few

populations remain (Jennings and Hayes

1994; Fellers 1999). Jennings and Hayes

(1994) noted a 50 percent decline in the

species across the Sierra Nevada based

on sampling historic mountain yellowlegged frog locations conducted before

the 1970s. Knapp and Matthews (2000)

noted that the 50 percent decline may

be conservative, as the sampling

conducted by Jennings and Hayes took

place in Sequoia and Kings Canyon

National Parks, where mountain yellowVerDate 11<MAY>2000 12:17 Oct 11, 2000 Jkt 194001 PO 00000 Frm 00014 Fmt 4702 Sfmt 4702 E:\FR\FM\12OCP1.SGM pfrm08 PsN: 12OCP1
Federal Register / Vol. 65, No. 198 / Thursday, October 12, 2000 / Proposed Rules 60605

legged frog populations are larger and

more abundant compared to

populations north of the Sierra National

Forest.

However, even in the protected areas

of Sequoia and Kings Canyon National

Parks, mountain yellow-legged frog

populations have undergone significant

declines. Bradford et al. (1994)

published results of two separate

studies which resurveyed historic sites

where mountain yellow-legged frogs

were documented between 1959 and

1979 in Sequoia and Kings Canyon

National Parks. They found mountain

yellow-legged frogs at only 12 of 49 sites

surveyed in 1989 and 1990. In addition,

mountain yellow-legged frogs had

disappeared from one of these 12 sites

by 1991.

Outside of Sequoia and Kings Canyon

National Parks, Bradford et al. (1994)

reported the absence of mountain

yellow-legged frogs at 21 of 24 historic

sites. In another study, Drost and Fellers

(1996) resurveyed 14 sites originally

surveyed in 1915 by Grinnell and Storer

(1924), and found only two now

occupied by the mountain yellowlegged frog. These surveys all strongly

suggest that the mountain yellow-legged

frog has systematically declined

throughout its range.

We have reviewed the petition and

other information available in the

Service’s files. Based upon this review,

we believe that substantial evidence

exists that listing the mountain yellowlegged frog as endangered may be

warranted. When we make a positive

finding, we also are required to

promptly commence a review of the

status of the species. Based upon

available and any newly obtained

information, we will issue a 12-month

finding as required by section 4(b)(3)(B)

of the Act. Petitioners also requested

that critical habitat be designated for the

Sierra Nevada population of the

mountain yellow-legged frog. The 12-

month finding will address this issue.

Public Information Requested

The Service hereby announces its

formal review of the species’ status

pursuant to this 90-day petition finding.

We request any additional data,

comments, and suggestions from the

public, other concerned government

agencies, the scientific community,

industry, and any other interested

parties concerning the status of the

mountain yellow-legged frog. Of

particular interest is information

regarding: (1) The existence and status

of additional subpopulations, (2) the

impact of nonnative fish introductions,

contaminants, livestock grazing,

acidification from atmospheric

deposition, nitrate deposition,

ultraviolet radiation, drought, disease,

and other factors that may be

responsible for the range-wide decline

of the species, (3) the implementation of

any actions that are benefitting the

species, and (4) genetic variability in

known subpopulations.

If you wish to comment, you may

submit your comments and materials

concerning this finding to the Field

Supervisor, Sacramento Fish and

Wildlife Office (see ADDRESSES section).

Our practice is to make comments,

including names and home addresses of

respondents, available for public review

during regular business hours.

Respondents may request that we

withhold their home address, which we

will honor to the extent allowable by

law. There also may be circumstances in

which we would withhold a

respondent’s identity, as allowable by

law. If you wish us to withhold your

name and/or address, you must state

this request prominently at the

beginning of your comment. However,

we will not consider anonymous

comments. To the extent consistent with

applicable law, we will make all

submissions from organizations or

businesses, and from individuals

identifying themselves as

representatives or officials of

organizations or businesses, available

for public inspection in their entirety.

Comments and materials received will

be available for public inspection, by

appointment, during normal business

hours at the above address.

References Cited

A complete list of all references cited

herein is available on request from the

Sacramento Fish and Wildlife Office,

(See ADDRESSES section).

Author: The primary author of this

document is Jason Davis, Sacramento

Fish and Wildlife Office (see ADDRESSES

section).

Authority

The authority for this action is the

Endangered Species Act of 1973, as

amended (16 U.S.C. 1531 et seq.).

Dated: October 5, 2000.

Jamie Rappaport Clark,

Director, Fish and Wildlife Service.

[FR Doc. 00–26179 Filed 10–11–00; 8:45 am]

BILLING CODE 4310–55–P

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife

and Plants: 90-Day Finding on a

Petition to List the California Spotted

Owl as Threatened or Endangered

AGENCY: Fish and Wildlife Service,

Interior.

ACTION: Notice of 90-day petition

finding.

SUMMARY: We, the U.S. Fish and

Wildlife Service (Service), announce a

90-day finding on a petition to list the

California spotted owl (Strix

occidentalis occidentalis) as threatened

or endangered, under the Endangered

Species Act (Act) of 1973, as amended

(16 U.S.C. 1531 et seq.). We find that the

petition presents substantial

information indicating that listing the

species may be warranted. A status

review is initiated.

DATES: The finding announced in this

document was made on October 5, 2000.

To be considered in the 12-month

finding for this petition, comments and

information should be submitted to the

Service by December 11, 2000.

ADDRESSES: Data, information,

comments, or questions concerning this

petition should be submitted to the

Field Supervisor; Sacramento Fish and

Wildlife Office; Sacramento Fish and

Wildlife Office; 2800 Cottage Way,

Room W–2605; Sacramento, California

95825. The petition finding, supporting

literature, and comments are available

for public inspection, by appointment,

during normal business hours at the

above address.

FOR FURTHER INFORMATION CONTACT:

Catherine Hibbard or Maria Boroja at the

Sacramento Fish and Wildlife Office

(see ADDRESSES section above), or at

(916) 414–6600.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(A) of the Endangered

Species Act (Act) of 1973, as amended

(16 U.S.C. 1531 et seq.), requires that the

Service make a finding on whether a

petition to list, delist, or reclassify a

species presents substantial information

indicating that the petitioned action

may be warranted. This finding is based

on information contained in the

petition, supporting information

submitted with the petition, and

information otherwise available to us at

the time we make the finding. To the

maximum extent practicable, we make

this finding within 90 days of the