Federal Register / Vol. 83, No. 111 / Friday, June 8, 2018 / Proposed Rules 26623 

Dated: May 7, 2018. 

Jonodev O. Chaudhuri, 

Chairman. 

Dated: May 1, 2018. 

Kathryn Isom-Clause, 

Vice Chair. 

Dated: May 4, 2018. 

E. Sequoyah Simermeyer, 

Associate Commissioner. 

[FR Doc. 2018–10365 Filed 6–7–18; 8:45 am] 

BILLING CODE 7565–01–P 

DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

50 CFR Part 17 

[Docket No. FWS–R6–ES–2018–0008; 

FXES11130900000–189–FF09E42000] 

RIN 1018–BC02 

Endangered and Threatened Wildlife 

and Plants; Removing Oenothera 

coloradensis (Colorado Butterfly Plant) 

From the Federal List of Endangered 

and Threatened Plants 

AGENCY: Fish and Wildlife Service, 

Interior. 

ACTION: Proposed rule. 

SUMMARY: We, the U.S. Fish and 

Wildlife Service (Service), propose to 

remove the Colorado butterfly plant 

(Oenothera coloradensis, currently 

listed as Gaura neomexicana ssp. 

coloradensis) from the Federal List of 

Endangered and Threatened Plants 

(List) due to recovery. This 

determination is based on a thorough 

review of the best available scientific 

and commercial data, which indicate 

that the threats to the Colorado butterfly 

plant have been eliminated or reduced 

to the point that it has recovered, and 

that this plant is no longer likely to 

become endangered in the foreseeable 

future and, therefore, no longer meets 

the definition of a threatened species 

under the Endangered Species Act of 

1973, as amended (Act). This proposed 

rule, if made final, would also remove 

the currently designated critical habitat 

for the Colorado butterfly plant. We are 

seeking information, data, and 

comments from the public on the 

proposed rule to remove the Colorado 

butterfly plant from the List (i.e., 

‘‘delist’’ the species). In addition, we are 

also seeking input on considerations for 

post-delisting monitoring of the 

Colorado butterfly plant. 

DATES: We will accept comments 

received or postmarked on or before 

August 7, 2018. Comments submitted 

electronically using the Federal 

eRulemaking Portal (see ADDRESSES, 

below), must be received by 11:59 p.m. 

Eastern Time on the closing date. We 

must receive requests for public 

hearings, in writing, at the address 

shown in FOR FURTHER INFORMATION

CONTACT by July 23, 2018. 

ADDRESSES: Written comments: You may 

submit written comments by one of the 

following methods: 

• Electronically: Go to the Federal 

eRulemaking Portal: http://

www.regulations.gov. In the Search box, 

enter Docket No. FWS–R6–ES–2018– 

0008, which is the docket number for 

this rulemaking. Then, click on the 

Search button. On the resulting page, in 

the Search panel on the left side of the 

screen, under the Document Type 

heading, click on the Proposed Rules 

link to locate this document. You may 

submit a comment by clicking on the 

blue ‘‘Comment Now!’’ box. If your 

comments will fit in the provided 

comment box, please use this feature of 

http://www.regulations.gov, as it is most 

compatible with our comment review 

procedures. If you attach your 

comments as a separate document, our 

preferred file format is Microsoft Word. 

If you attach multiple comments (such 

as form letters), our preferred formation 

is a spreadsheet in Microsoft Excel. 

• By hard copy: Submit by U.S. mail 

or hand-delivery to: Public Comments 

Processing, Attn: FWS–R6–ES–2018– 

0008; U.S. Fish and Wildlife Service; 

MS: BPHC; 5275 Leesburg Pike, Falls 

Church, VA 22041–3803. 

We request that you submit written 

comments only by the methods 

described above. We will post all 

comments on http://

www.regulations.gov. This generally 

means that we will post any personal 

information you provide us (see Public 

Comments, below, for more details). 

Document availability: This proposed 

rule and supporting documents, 

including a copy of the draft postdelisting monitoring plan referenced in 

this document, are available on http:// 

www.regulations.gov at Docket No. 

FWS–R6–ES–2018–0008. In addition, 

the supporting file for this proposed 

rule will be available for public 

inspection, by appointment, during 

normal business hours at the Wyoming 

Ecological Services Field Office; 5353 

Yellowstone Road, Suite 308A, 

Cheyenne, WY 82009; telephone: 307– 

772–2374. Persons who use a 

telecommunications device for the deaf 

(TDD) may call the Federal Relay 

Service at 800–877–8339. 

FOR FURTHER INFORMATION CONTACT: 

Tyler A. Abbott, Field Supervisor, 

telephone: 307–772–2374. Direct all 

questions or requests for additional 

information to: COLORADO 

BUTTERFLY PLANT QUESTIONS, U.S. 

Fish and Wildlife Service; Wyoming 

Ecological Services Field Office; 5353 

Yellowstone Road, Suite 308A, 

Cheyenne, WY 82009. Individuals who 

are hearing-impaired or speechimpaired may call the Federal Relay 

Service at 800–877–8339. 

SUPPLEMENTARY INFORMATION: 

Information Requested 

Public Comments 

We want any final action resulting 

from this proposal to be as accurate as 

possible. Therefore, we invite tribal and 

governmental agencies, the scientific 

community, industry, and other 

interested parties to submit comments 

or recommendations concerning any 

aspect of this proposed rule. Comments 

should be as specific as possible. We 

particularly seek comments and new 

information concerning: 

(1) Our analyses of the Colorado 

butterfly plant’s abundance, 

distribution, and population trends; 

(2) Potential impacts from 

disturbances, such as grazing and 

residential, urban, and energy 

development; 

(3) Conservation activities within the 

plant’s range; 

(4) Potential impacts from the effects 

of climate change; and 

(5) Input on considerations for postdelisting monitoring of the Colorado 

butterfly plant. 

Please include sufficient supporting 

information with your submission (such 

as scientific journal articles or other 

publications) to allow us to verify any 

scientific or commercial information 

you include. Please note that 

submissions merely stating support for 

or opposition to the action under 

consideration without providing 

supporting information, although noted, 

may not meet the standard of 

information required by section 

4(b)(1)(A) of the Act (16 U.S.C. 1531 et 

seq.), which directs that determinations 

as to whether any species is an 

endangered or threatened species must 

be made ‘‘solely on the basis of the best 

scientific and commercial data 

available.’’ 

To issue a final rule to implement this 

proposed action, we will take into 

consideration all comments and any 

additional information we receive. Such 

communications may lead to a final rule 

that differs from this proposal. All 

comments, including commenters’ 

names and addresses, if provided to us, 

will become part of the supporting 

record. 


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26624 Federal Register / Vol. 83, No. 111 / Friday, June 8, 2018 / Proposed Rules 

You may submit your comments and 

materials concerning the proposed rule 

by one of the methods listed in 

ADDRESSES. Comments must be 

submitted to http://www.regulations.gov 

before 11:59 p.m. (Eastern Time) on the 

date specified in DATES. We will not 

consider hand-delivered comments that 

we do not receive, or mailed comments 

that are not postmarked, by the date 

specified in DATES. 

We will post your entire comment–– 

including your personal identifying 

information––on http://

www.regulations.gov. If you provide 

personal identifying information in your 

comment, you may request at the top of 

your document that we withhold this 

information from public review. 

However, we cannot guarantee that we 

will be able to do so. 

Comments and materials we receive, 

as well as supporting documentation we 

used in preparing this proposed rule, 

will be available for public inspection 

on http://www.regulations.gov, or by 

appointment, during normal business 

hours at the U.S. Fish and Wildlife 

Service, Wyoming Ecological Services 

Field Office (see Document availability 

under ADDRESSES, above). 

Public Hearing 

Section 4(b)(5) of the Act provides for 

one or more public hearings on this 

proposal, if requested. Requests must be 

received within 45 days after the date of 

publication of this proposed rule in the 

Federal Register (see DATES, above). 

Such requests must be sent to the 

address shown in FOR FURTHER

INFORMATION CONTACT. We will schedule 

a public hearing on this proposal, if any 

is requested, and announce the date, 

time, and place of the hearing, as well 

as how to obtain reasonable 

accommodations, in the Federal 

Register and local newspapers at least 

15 days before the hearing. 

Peer Review 

In accordance with our policy, 

‘‘Notice of Interagency Cooperative 

Policy for Peer Review in Endangered 

Species Act Activities,’’ published on 

July 1, 1994 (59 FR 34270), we will seek 

the expert opinion of at least three 

appropriate and independent specialists 

regarding scientific data and 

interpretations contained in this 

proposed rule. We will send copies of 

this proposed rule to the peer reviewers 

immediately following its publication in 

the Federal Register. We will ensure 

that the opinions of peer reviewers are 

objective and unbiased by following the 

guidelines set forth in the Director’s 

Memo that updates and clarifies Service 

policy on peer review (USFWS 2016a). 

The purpose of such review is to ensure 

that our decisions are based on 

scientifically sound data, assumptions, 

and analysis. Accordingly, our final 

decision may differ from that described 

in this proposal. 

Previous Federal Actions 

On October 18, 2000, we published a 

rule in the Federal Register (65 FR 

62302) listing the Colorado butterfly 

plant, with the scientific name Gaura 

neomexicana ssp. coloradensis, as a 

federally threatened species. On January 

11, 2005, we designated critical habitat 

for the Colorado butterfly plant (70 FR 

1940). 

On May 25, 2010, we developed a 

recovery outline that laid out a 

preliminary course of action for the 

recovery of the Colorado butterfly plant. 

This recovery outline identified 

residential and urban development as 

the most immediate and severe threat to 

the species, with mowing and haying as 

an additional potential threat. A 

recovery plan has not been developed 

for this species, although a draft was 

assembled prior to the species’ listing by 

the Service, the Nature Conservancy, 

and the Wyoming Natural Diversity 

Database in 1987 (USFWS 1987, entire). 

On December 17, 2012, we completed 

a 5-year review of the Colorado butterfly 

plant. The review was revised in June 

2016, to remove private information 

protected under wildlife extension 

agreements (WEAs) from the document. 

The 5-year review concluded that the 

species should remain listed as 

threatened but also stated that threats 

currently affecting the species were 

occurring at low levels overall for 

Colorado butterfly plant populations 

and recommended further actions and 

analyses prior to the next 5-year review 

to assist in determining whether the 

species could be delisted. 

Species Description and Life History 

Detailed information regarding the 

Colorado butterfly plant’s biology and 

life history can be found in the Species 

Biological Report for Colorado butterfly 

plant (USFWS 2017a, pp. 6–7), which 

was reviewed by recovery partners. The 

Species Biological Report is an in-depth 

review of the species’ biology and 

threats, an evaluation of its biological 

status, and an assessment of the 

resources and conditions needed to 

maintain long-term viability. The 

Species Biological Report is an interim 

approach taken as we transition to using 

a Species Status Assessment (SSA) 

framework as the standard format that 

the Service uses to analyze species as 

we make decisions under the Act, and 

includes similar analyses of the species’ 

viability in terms of its resiliency, 

redundancy, and representation 

(USFWS 2016b, entire). We summarize 

relevant information below. 

The Colorado butterfly plant is a 

short-lived perennial herb that is 

monocarpic or semelparous, meaning 

that it flowers once, sets seed, and then 

dies. Flowering plants may, on rare 

occasions, flower a second year or 

become vegetative the year after 

flowering (Floyd 1995, pp. 10–15, 32). 

Pollinators for related species of Gaura 

and Colyphus (Onagraceae, tribe 

Onagreae) consist of noctuid moths 

(Noctuidae) and halictid bees 

(Lasioglossum; Clinebell et al. 2004, p. 

378); both moths and bees have been 

identified visiting Colorado butterfly 

plant flowers during annual surveys 

(USFWS 2016c, entire). Additionally, 

one study found that the Colorado 

butterfly plant does not exhibit a 

bimodal (day and night) pollination 

system that is seen in other Gaura 

species, since the majority of pollination 

occurs at night by noctuid moths 

(Krakos et al. 2013, entire). 

The Colorado butterfly plant is selfcompatible; plants produce flowers 

capable of forming viable seed with 

pollen from the same plant (Floyd 1995, 

p. 4). During dispersal, many seeds fall 

to the ground around parent plants 

(Floyd and Ranker 1998, p. 854). 

Because the seed floats, it also may be 

dispersed downstream. Livestock and 

native ungulates could provide an 

important dispersal mechanism as well, 

through ingestion of the seeds (USFWS 

2012, p. 27). Populations of this species 

show evidence of a seedbank, an 

adaptation that enables the species to 

take advantage of favorable growing 

seasons, particularly in flood-prone 

areas (Holzel and Otte 2004, p. 279). 

The number of individuals in a 

population of Colorado butterfly plants 

appears to be influenced by rates of 

seedling establishment and survival of 

vegetative rosettes to reproductive 

maturity. These factors may be 

influenced by summer precipitation 

(Floyd and Ranker 1998, p. 858; Fertig 

2000, p. 13). The combination of cool 

and moist spring months is important in 

germination, and germination levels 

influence the outcome of flowering 

plant population census in subsequent 

years. Additionally, summer conditions, 

and temperature in particular, appear to 

be an important mortality factor rather 

than influencing germination (Laursen 

and Heidel 2003, p. 6). Differences in 

soil moisture and vegetation cover may 

also influence recruitment success 

(Munk et al. 2002, p. 123). 

The vegetative rosettes within a 

population may provide an important 


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and particularly resilient stage of the life 

history of this species. Individual 

vegetative rosettes appear to be capable 

of surviving adverse stochastic events 

such as flooding (Mountain West 

Environmental Services 1985, pp. 2–3) 

and adverse climatic years when new 

seedling establishment is low. 

Therefore, episodic establishment of 

large seedling recruitment classes may 

be important for the long-term growth, 

replenishment, and survival of 

populations (Floyd and Ranker 1998, 

entire). 

Taxonomy 

The Colorado butterfly plant, a 

member of the evening primrose family 

(Onagraceae), was listed as Gaura 

neomexicana ssp. coloradensis in 2000 

(65 FR 62302; October 18, 2000). 

Molecular studies by Hoggard et al. 

(2004, p. 143) and Levin et al. (2004, pp. 

151–152) and subsequent revisions of 

the classification of the family 

Onagraceae (Wagner et al. 2007, p. 211) 

transferred the taxon previously known 

as Gaura neomexicana Wooton to 

Oenothera as Oenothera coloradensis 

ssp. neomexicana (Wooton) W.L. 

Wagner & Hoch. More recent analyses 

showed that there are no infraspecific 

entities (any taxa below the rank of 

species) within the taxon; the listed 

entity is now recognized as Oenothera 

coloradensis (Wagner et al. 2013, p. 67). 

A more detailed assessment of the 

taxonomy of the Colorado butterfly 

plant is available in the species 

Biological Report (USFWS 2017a, pp. 

4–6). The taxonomic and nomenclatural 

changes do not alter the description, 

range, or threat status of the listed 

entity. 

Throughout this proposed rule, we 

will use the current scientific name and 

rank, Oenothera coloradensis, for the 

Colorado butterfly plant. We 

acknowledge, however, that the listing 

of the Colorado butterfly plant in the 

Code of Federal Regulations (CFR) will 

continue to be identified as Gaura 

neomexicana ssp. coloradensis until 

such time as we publish a correction or 

a final delisting rule in the Federal 

Register. 

Species Abundance, Habitat, and 

Distribution 

The Colorado butterfly plant is a 

regional endemic riparian species 

known from 34 12-digit hydrologic unit 

code watersheds (watersheds) (28 extant 

and 6 extirpated), found from Boulder, 

Douglas, Larimer, and Weld Counties in 

Colorado, Laramie and Platte Counties 

in Wyoming, and western Kimball 

County in Nebraska (see figure below). 

Prior to 1984, few extensive searches for 

the plant had been conducted, and data 

taken from herbarium specimens were 

the primary basis of understanding the 

extent of the species’ historical 

distribution. At that time, the plant was 

known from a few historical and 

presumably extirpated locations in 

southeastern Wyoming and several 

locations in northern Colorado, as well 

as from three extant occurrences in 

Laramie County in Wyoming and Weld 

County in Colorado. Prior to listing, 

extensive surveys were conducted in 

1998, to document the status of the 

known occurrences, and all still 

contained Colorado butterfly plants 

(Fertig 1998a, entire). 

BILLING CODE 4333–15–P 


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BILLING CODE 4333–15–C 

Habitat Description 

The Colorado butterfly plant occurs 

on subirrigated (water reaches plant root 

zone from below the soil surface), 

alluvial soils derived from 

conglomerates, sandstones, and 

tuffaceous mudstones and siltstones of 

the Tertiary White River, Arikaree, and 

Oglalla Formations (Love and 

Christiansen 1985 in Fertig 2000, p. 6) 

on level or slightly sloping floodplains 

and drainage bottoms at elevations of 

1,524–1,951 meters (m) (5,000–6,400 

feet (ft)). Populations are typically found 

in habitats created and maintained by 

streams active within their floodplains, 

with vegetation that is relatively open 

and not overly dense or overgrown (65 

FR 62302; October 18, 2000). 

Populations occur in a range of 

ecological settings, including 

streamside, outside of the stream 

channel but within the floodplain, and 

spring-fed wet meadows. The plant is 

often found in but not restricted to 

early- to mid-succession riparian 

habitat. Historically, flooding was 

probably the main cause of disturbances 

in the plant’s habitat, although wildfire 

and grazing by native herbivores also 

may have been important. Although 

flowering and fruiting stems may 

exhibit increased dieback because of the 

abovementioned events, vegetative 

rosettes appear to be little affected 

(Mountain West Environmental Services 

1985, pp. 2–3). 

It commonly occurs in communities 

dominated by nonnative and 

disturbance-tolerant native species 

including: Agrostis stolonifera (creeping 

bentgrass), Poa pratensis (Kentucky 

bluegrass), Glycyrrhiza lepidota 

(American licorice), Cirsium flodmanii 

(Flodman’s thistle), Grindelia squarrosa 

(curlytop gumweed), and Equisetum 

laevigatum (smooth scouring rush). Its 

habitat on Warren Air Force Base (AFB) 

includes wet meadow zones dominated 

by Panicum virgatum (switchgrass), 

Muhlenbergia richadrsonis (mat muhly), 

Schizachyrium scoparium (little 

bluestem), Spartina pectinata (prairie 

cordgrass), and other native grasses. All 

of these habitat types are usually 

intermediate in moisture ranging from 

wet, streamside communities dominated 

by sedges, rushes, and cattails to dry, 

upland prairie habitats (Fertig 1998a, 

pp. 2–4). 

Typically, Colorado butterfly plant 

habitat is open, without dense or woody 

vegetation. The establishment and 

survival of seedlings appears to be 

enhanced at sites where tall and dense 

vegetation has been removed by some 

form of disturbance. In the absence of 

occasional disturbance, the plant’s 

habitat can become choked by dense 

growth of willows, grasses, and exotic 

plants (Fertig 1996, p. 12). This prevents 

new seedlings from becoming 

established and replacing plants that 

have died (Fertig 1996, pp. 12–14). 

For the purposes of this analysis, we 

consider all occurrences of the Colorado 


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butterfly plant within the same 

watershed to be one population. There 

are no data (e.g., genetic relatedness) 

available to more precisely define 

populations, and although distance of 1 

km (0.6 mi) or greater may exceed the 

distance traveled by pollinators, it is 

possible that seeds may disperse over 

much greater distances (Heidel 2016, 

pers. comm.). Therefore, because these 

gaps are probably too small to prevent 

the dispersal of pollinators and/or seeds 

between subpopulations, colonies along 

the same stream reach should be 

considered part of the same population. 

This varies from the characterization of 

populations in both the listing decision 

(65 FR 62302; October 18, 2000) and 

critical habitat designation (70 FR 1940; 

January 11, 2005), where populations 

were defined by landowner and/or 

proximity within a drainage. We find 

organizing populations by watershed 

more accurately describes components 

of population ecology (genetic exchange 

within a geographic area), and stressors 

affecting the species tend to vary by 

watershed. Because of this new 

organization of population structure, 

some populations considered distinct 

and separate during the 2000 listing 

decision are now combined and vice 

versa, although many populations are 

the same in this proposed rule as they 

were presented in the 2000 listing rule. 

Population Abundance and Trends 

The Colorado butterfly plant occurred 

historically and persists in various 

ecological settings described above 

under Habitat Description including wet 

meadows, stream channels, stream 

floodplains, and spring-fed wetlands. A 

detailed summary of the status of the 

species between 1979 and 2016 is 

provided in the species’ Biological 

Report (USFWS 2017a, pp. 13–22). 

In 1998 and 1999, in preparation for 

listing the species, the rangewide census 

of flowering individuals was estimated 

at 47,300 to 50,300, with the majority of 

these occurring in Wyoming (Fertig 

1998a, p. 5; Fertig 2000, pp. 8–13). 

However, a population was discovered 

in Colorado in 2005 that had a peak 

census of 26,000 plants in 2011, 

bringing the total rangewide population 

to approximately 73,300 to 76,300 

plants over time. Another population 

was discovered upstream of known 

populations on Horse Creek in Laramie 

County, Wyoming, in 2016 with only 17 

individuals, although the area had just 

been hayed and was likely an 

incomplete representation of the total 

number of plants in this population 

(USFWS 2016c, entire). 

Average numbers may be a more 

appropriate way to represent 

populations than the minimum and 

maximum values, although all provide 

insight into the population’s resiliency, 

or the ability to withstand stochastic 

events. The number of reproductive 

individuals in a population is somewhat 

driven by environmental factors and 

varies considerably, so understanding 

the variability in the number of 

individuals present in any given year is 

meaningful in assessing population 

resiliency. Population numbers have 

fluctuated five-fold over the course of 

the longest-running monitoring study 

(28 years) conducted on Warren AFB. 

There, the population peaked at over 

11,000 flowering plants in 1999 and 

2011, making it one of the largest 

populations rangewide, and then 

dropped to 1,916 plants in 2008 (Heidel 

et al. 2016, p. 1). The Warren AFB 

population numbers provide some 

indication of how population numbers 

can vary in landscapes not managed for 

agricultural purposes, and it is likely 

that numbers vary even more 

dramatically on managed landscapes. If 

this fluctuation was applied to the 

rangewide population estimates above, 

then total rangewide numbers for 

average years might be less than 50 

percent of rangewide estimates in 

favorable years (Handwerk 2016, pers. 

comm.; Heidel 2016, pers. comm.). 

The final listing rule (65 FR 62302; 

October 18, 2000) defined large 

populations as those containing more 

than 3,000 reproductive individuals; 

moderate populations as those 

containing 500 to 2,500 reproductive 

individuals; and small populations 

having fewer than 500 reproductive 

individuals. At the time, the species was 

represented by 10 stable or increasing 

populations, 4 extant but declining 

populations, 3 likely small populations, 

and 9 likely extirpated populations. 

However, after monitoring roughly half 

the known populations annually for the 

past 13 years, we understand that 

population size fluctuates significantly 

from year to year; therefore, population 

size in any given year is not a good 

indicator of resiliency. Therefore, our 

estimates of resiliency are now based on 

averages of population censuses over 

multiple years and trends of 

populations in response to management 

and stressors. Based on this, we now 

have 15 highly resilient populations, 2 

moderately resilient populations, 6 low 

resiliency populations, 2 populations 

with unknown resiliency, 3 introduced 

populations, and records of 6 extirpated 

populations. 

Colorado 

In 2005, when critical habitat was 

designated for the Colorado butterfly 

plant, only a single population was 

known from Colorado. That population 

was not designated as critical habitat 

because it was protected under a WEA. 

Currently, the species is known to occur 

in Adams, Boulder, Douglas, Jefferson, 

Larimer, and Weld Counties in northern 

Colorado, spanning 12 watersheds (see 

figure above). Six historical occurrences 

have not been documented since 1984, 

and are presumed extirpated. Three of 

the eight records in Colorado are 

introduced and do not represent 

indigenous populations, and are either 

seeded into the wild or into a garden. 

These introduced sites were not 

designed specifically for species’ 

conservation, and therefore are not the 

focus of this species status evaluation in 

Colorado. 

The majority of Colorado butterfly 

plants in Colorado are located on lands 

managed by the City of Fort Collins 

Natural Areas Department (Ft. Collins or 

CFCNAD) in Weld and Larimer 

Counties. The plants are distributed 

among three distinct habitats on either 

side of Interstate 25 and have numbered 

between 3 to more than 26,000 

reproductive individuals. These areas 

are being managed to maintain suitable 

habitat for the species (CFCNAD 2008, 

p. 1; CFCNAD 2010, p. 1; CFCNAD 

2011a, entire; CFCNAD 2011b, entire; 

CFCNAD 2014, entire). Annual census 

information on flowering individuals at 

the Meadow Springs Ranch in Weld 

County indicates that the large 

fluctuations in population numbers are 

actually around a stable mean (434 

flowering plant average, median of 205, 

range of 45¥1,432 flowering plants). 

Other populations in Colorado have not 

been routinely monitored; consequently, 

no trend information is available 

(USFWS 2016c, entire). In summary, the 

species is represented in Colorado by 

two highly resilient, three low 

resiliency, and three introduced 

populations. 

Nebraska 

Populations of the Colorado butterfly 

plant in Nebraska are considered at the 

edge of the species’ range and exist at 

higher elevations than we knew at the 

time we listed the species. Surveys 

conducted in 1985, along Lodgepole 

Creek near the Nebraska/Wyoming 

border in Kimball County, found just 

over 2,000 flowering plants (Rabbe 

2016, pers. comm). A survey in 1992 

found two populations of Colorado 

butterfly plant: One population (547 

plants) along Lodgepole Creek and one 

population (43 plants) at Oliver 

Reservoir State Recreation Area (SRA) 

in the southwest panhandle of Nebraska 

in Kimball County (Fertig 2000a, p. 12). 


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Survey results from 2004 suggested the 

species was extirpated from the State. In 

2005, no critical habitat was designated 

in Nebraska. However, a 2008 survey 

along historically occupied habitat and 

the Oliver Reservoir SRA, located 12 

plants in four locations on private lands 

along Lodgepole Creek: 5 plants in areas 

where the species had been located 

before and 7 plants in areas newly 

watered by a landowner piping water 

into Lodgepole Creek from a cattle stock 

tank. No plants were found at the Oliver 

Reservoir SRA (Wooten 2008, p. 4). 

These areas have not been surveyed 

since 2008. Outside of these 

occurrences, no other populations of the 

species are known to occur in Nebraska 

(Rabbe 2016, pers. comm.). 

Wyoming 

Extant populations of Colorado 

butterfly plant in Wyoming occur 

throughout most of Laramie County and 

extend northward into Platte County 

(USFWS 2012, pp. 11–21), spanning 17 

watersheds (see figure above). Over 90 

percent of known occurrences in 

Wyoming are on private lands, with 

parts of two occurrences on State school 

trust lands, one occurrence on State 

lands, and one occurrence on Federal 

lands. Populations in Wyoming that are 

found partly or fully on State school 

trust lands are managed for agricultural 

uses. The population on Federal lands 

occurs on Warren AFB located adjacent 

to Cheyenne, provides information on 

species trends as it may have occurred 

prior to human settlement of the area 

(with wild grazers and natural 

streamflow), and represents the level of 

hydrological complexity of three 

different sizes of streams. The highest 

census numbers at Warren AFB totaled 

over 11,000 plants in 1998 and 2011, 

and the mean census numbers for all 

other years have remained at or above 

50 percent of that peak, based on 1988– 

2016 numbers (Heidel et al. 2016, pp. 

11–14). 

In terms of genetic representation, a 

study conducted on Colorado butterfly 

plants occupying three drainages at 

Warren AFB found that one of the 

drainages was genetically unique and 

more diverse than the other two 

drainages (Floyd 1995, pp. 73–81). 

Another study at Warren AFB found 

that plants in one of the drainages 

contained unique alleles, sharing 

genetic composition with only a small 

number of individuals from the second 

and no individuals of the third drainage, 

indicating fine-scale genetic variability 

within that portion of the species’ range 

(Tuthill and Brown 2003, p. 251). 

Assuming similar genetic structure 

across the species’ range, this result 

suggests a high degree of genetic 

representation at the species’ level. This 

genetic information, however, does not 

provide sufficient strength in terms of 

sample size in discerning populations 

from each other. 

The Service has agreements with 11 

private landowners within six 

watersheds in Laramie County, 

Wyoming, and one watershed in Weld 

County, Colorado (described in detail 

under Conservation Efforts, below), 

since 2004 to conduct annual 

monitoring of the Colorado butterfly 

plant. We also provide management 

recommendations to help landowners 

maintain habitat for the species. Many 

of the landowners graze cattle or horses 

where the species occurs; others use the 

areas for haying operations. Populations 

at these locations may fluctuate by as 

much as 100-fold annually (USFWS 

2012, pp. 11–21; USFWS 2016c, entire). 

For example, one population was 

heavily grazed for over a decade, 

leading to counts of fewer than 30 

reproductive individuals for several 

years, but when the grazing pressure 

was relieved, the population rebounded 

within 1 year to more than 600 

reproductive individuals (USFWS 

2016c, entire). This may indicate that 

either a robust seedbank was present or 

vegetative rosettes avoided the intense 

grazing pressure and bolted after grazing 

diminished. The total number of plants 

counted in Wyoming under these 

agreements has varied from 

approximately 1,000 to over 21,000 

reproductive individuals since 2004. 

Combining annual census numbers from 

all monitored populations in Wyoming, 

we have observed small to extreme 

population fluctuations (USFWS 2012, 

pp. 11–21; USFWS 2016c, entire). 

Wyoming is represented by 13 highly 

resilient populations, 2 moderately 

resilient populations, and 2 populations 

with unknown resiliency due to lack of 

information. 

The listing decision (65 FR 62302, 

October 18, 2000, see p. 62308) stated 

that ‘‘[i]n order for a population to 

sustain itself, there must be enough 

reproducing individuals and sufficient 

habitat to ensure survival of the 

population. It is not known if the 

scattered populations of [the Colorado 

butterfly plant] contain sufficient 

individuals and diversity to ensure their 

continued existence over the long 

term.’’ Today, we understand that, 

regarding ecological representation, the 

species is characterized by having at 

least one population within each 

ecological setting and within all but the 

southern-most portions of the historical 

range. Furthermore, most extant 

populations have high resiliency (with 

more than 100 reproductive individuals 

in most years). Additionally, most 

populations contain individuals in more 

than one ecological setting, such as 

individuals along the creek bank and 

individuals outside of the creek bank 

and in the floodplain of the creek. While 

surveyors typically census the number 

of flowering individuals during surveys 

due to relative ease in counting, the 

number of flowering plants in a survey 

location in any given year does not 

represent the resiliency of the 

population. Resiliency is determined 

through a combination of number of 

flowering individuals, trends in this 

number, and response of the population 

to stochastic events. 

Conservation Efforts 

The Service has worked with partners 

to protect existing populations. Much of 

this work has been accomplished 

through voluntary cooperative 

agreements. For example, beginning in 

2004, the Service has entered into 11 

WEAs with private landowners, 

representing six watersheds, to manage 

riparian habitat for Colorado butterfly 

plant (70 FR 1940; January 11, 2005). 

These 15-year WEAs cover a total of 

1,038 hectares (ha) (2,564 acres (ac)) of 

the species’ habitat along 59 km (37 mi) 

of stream. These agreements represent 

approximately one-third of the known 

populations of Colorado butterfly plant 

in Wyoming and Colorado, including 

some of the largest populations on 

private lands. All of the landowners 

have agreed to the following: 

(1) Allow Service representatives or 

their designee access to the property for 

monitoring or fence installation; 

(2) Coordinate hay cutting activities in 

areas managed primarily for hay 

production to consider the Colorado 

butterfly plant’s seed production needs; 

(3) Prevent application of herbicides 

closer than 30.5 m (100 ft) from known 

subpopulations of the Colorado butterfly 

plant; and 

(4) Manage livestock grazing activities 

in conjunction with conservation needs 

of the Colorado butterfly plant. 

One of the landowners signed a 10- 

year agreement instead of a 15-year 

agreement that was renewed for an 

additional 10 years in 2015. The 

remaining agreements expire in late 

2019. We anticipate that participating 

landowners will continue to support the 

work being performed under the WEAs 

and will seek renewal of these 

agreements if the species remains listed 

under the Act. Based on the ongoing 

relationship that the Service has with 

these participating landowners, we 

anticipate that they would support the 

inclusions of their properties under the 


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post-delisting monitoring program 

should the Colorado butterfly plant be 

delisted. 

One of the benefits of the WEAs for 

both the Service and private landowners 

is that we can review the population 

numbers annually and together develop 

management recommendations to 

improve growing conditions for the 

species. Populations occurring within 

designated critical habitat (see figure, 

above) have not been surveyed since 

2004, and their trends, threats, and 

viabilities are uncertain. However, no 

projects potentially impacting critical 

habitat for this species have occurred. 

Additionally, we reviewed aerial 

imagery of the critical habitat units and 

found only two minimal changes 

between 2004 and 2015 (reflecting 

habitat conditions at the time of 

designation and the most recent aerial 

imagery available) throughout all 

critical habitat units; these changes 

affect only a few acres of designated 

critical habitat (USFWS 2017b, entire). 

Consequently, we determine that 

activities occurring on critical habitat 

are likely the same as they were at the 

time of designation. Furthermore, 

because many of the private lands 

included in the critical habitat 

designation are adjacent to lands under 

WEAs, we determine that the 

populations occurring within 

designated critical habitat are likely 

stable, and fluctuating similarly to 

populations on lands that we monitor 

under WEAs. We have no reason to 

believe that populations occurring on 

designated critical habitat are 

responding to stressors differently than 

those populations we monitor. 

Therefore, populations throughout the 

species’ range on private, local, and 

Federal lands either have been observed 

to be, or are highly likely to be, 

fluctuating around a stable population 

size. 

The Service and the U.S. Air Force 

signed a memorandum of agreement 

(MOA) on January 18, 1982 (updated in 

1999 and 2004) to facilitate the 

preservation, conservation, and 

management of the Colorado butterfly 

plant (USFWS 1982, entire; USFWS 

1999, entire; USFWS 2004, entire). In 

2004, Warren AFB developed a 

conservation and management plan for 

the species (Warren AFB 2004, entire) 

that was added to their integrated 

natural resources management plan in 

2014 (Warren AFB 2014, entire). 

Through these plans, the Service 

partners with the U.S. Air Force and 

Wyoming Natural Diversity Database to 

monitor and protect the population of 

the Colorado butterfly plant on the 

Warren AFB. This includes annual 

monitoring; nonnative, invasive species 

control and eradication; and 

maintenance of appropriate floodplain 

characteristics for the species. Based on 

29 years of monitoring and 

management, the population of the 

Colorado butterfly plant on the Warren 

AFB is doing well, with some areas 

declining while others are increasing 

(Heidel et al. 2016, entire). 

Three populations in Larimer and 

Weld Counties, Colorado, occur on 

properties owned by the City of Fort 

Collins, and two are among the largest 

across the species’ range. The City of 

Fort Collins developed a 10-year master 

plan for the Natural Areas Department 

in 2014, which provides a framework 

for the conservation and preservation of 

natural areas, including the populations 

of the Colorado butterfly plant. The 

master plan prescribes conservation 

actions that allow for the persistence of 

the Colorado butterfly plant on the 

landscape (CFCNAD 2016a, entire), 

including prescribed burns to eliminate 

competition, managed grazing, and 

improved security of water flow to the 

species’ habitat. 

In summary, these agreements and 

plans have provided useful data, 

facilitated good management of nine of 

the largest and most resilient 

populations, and resulted in stable or 

increasing population trends. Because of 

the information we obtained through 

these agreements and plans, we are able 

to understand the resilience of 

individual plants and populations, the 

representation of the species within its 

ecological settings, and the redundancy 

of the plant population’s numbers and 

potential for connectivity. 

Summary of Factors Affecting the 

Species 

Section 4 of the Act and its 

implementing regulations (50 CFR part 

424) set forth the procedures for listing 

species, reclassifying species, or 

removing species from listed status. 

‘‘Species’’ is defined by the Act as 

including any species or subspecies of 

fish or wildlife or plants, and any 

distinct vertebrate population segment 

of fish or wildlife that interbreeds when 

mature (16 U.S.C. 1532(16)). A species 

may be determined to be an endangered 

or threatened species due to one or more 

of the five factors described in section 

4(a)(1) of the Act: (A) The present or 

threatened destruction, modification, or 

curtailment of its habitat or range; (B) 

overutilization for commercial, 

recreational, scientific, or educational 

purposes; (C) disease or predation; (D) 

the inadequacy of existing regulatory 

mechanisms; or (E) other natural or 

manmade factors affecting its continued 

existence. 

Determining whether the status of a 

species has improved to the point that 

it can be downlisted (i.e., reclassified 

from endangered to threatened) or 

delisted requires consideration of 

whether the species meets the 

definitions of either an endangered 

species or threatened species contained 

in the Act. For species that are already 

listed as endangered species or 

threatened species, this analysis of 

threats is an evaluation of both the 

threats currently facing the species and 

the threats that are reasonably likely to 

affect the species in the foreseeable 

future following the delisting or 

downlisting and the removal or 

reduction of the Act’s protections. 

A species is an ‘‘endangered species’’ 

for purposes of the Act if it is in danger 

of extinction throughout all or a 

significant portion of its range and is a 

‘‘threatened species’’ if it is likely to 

become an endangered species within 

the foreseeable future throughout all or 

a significant portion of its range. The 

word ‘‘range’’ in the significant portion 

of its range phrase refers to the range in 

which the species currently exists, and 

the word ‘‘significant’’ refers to the 

value of that portion of the range being 

considered to the conservation of the 

species. We consider ‘‘foreseeable 

future’’ as that period of time within 

which a reliable prediction can be 

reasonably relied upon in making a 

determination about the future 

conservation status of a species, as 

described in the Solicitor’s opinion 

dated January 16, 2009. We consider 15 

to 20 years to be a reasonable period of 

time within which reliable predictions 

can be made for the Colorado butterfly 

plant. This time period includes at least 

five generations of the species, 

coincides with the duration of one 

renewal of the WEAs expiring in 2019, 

and aligns with the timeframes for 

predictions regarding municipal 

development and growth in the area. 

For the purposes of this analysis, we 

first evaluate the status of the species 

throughout all of its range, then 

consider whether the species is in 

danger of extinction or likely to become 

so in any significant portion of its range. 

In considering what factors might 

constitute threats, we must look beyond 

the exposure of the species to a 

particular factor to evaluate whether the 

species may respond to the factor in a 

way that causes actual impacts to the 

species. If there is exposure to a factor, 

but no response, or only a positive 

response, that factor is not a threat. If 

there is exposure to a factor and the 

species responds negatively, the factor 


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may be a threat, and we attempt to 

determine how significant a threat it is. 

If the threat is significant it may drive, 

or contribute to, the risk of extinction of 

the species such that the species 

warrants listing as an endangered 

species or a threatened species as those 

terms are defined by the Act. This does 

not necessarily require empirical proof 

of a threat. The combination of exposure 

and some corroborating evidence of how 

the species is likely impacted could 

suffice. The mere identification of 

factors that could impact a species 

negatively is not sufficient to compel a 

finding that listing is appropriate; we 

require evidence that these factors 

individually or cumulatively are 

operative threats that act on the species 

to the point that the species meets the 

definition of an endangered species or 

threatened species under the Act. 

The Colorado butterfly plant is 

federally listed as threatened. Below, we 

present a summary of threats affecting 

the species and its habitats in the past, 

present, and predicted into the future. A 

detailed evaluation of factors affecting 

the species at the time of listing can be 

found in the listing determination (65 

FR 62302; October 18, 2000) and 

designation of critical habitat (70 FR 

1940; January 11, 2005). An evaluation 

of factors affecting the species after 2005 

can be found in the 2012 5-year review 

(USFWS 2012, entire). The primary 

threats to the species identified at the 

time of listing include overgrazing by 

cattle or horses, haying or mowing at 

inappropriate times of the year, habitat 

degradation resulting from vegetation 

succession or urbanization of the 

habitat, habitat conversion to cropland 

or subdivision, water development, 

herbicide spraying, and competition 

with exotic plants (Marriott 1987, pp. 

26–27; Fertig 1994, pp. 39–41, Fertig 

2000a, pp. 16–17). Since the time of 

listing, oil and gas development and the 

effects of climate change have become 

potential threats to this species and are 

analyzed under Factor A and Factor E, 

respectively, below. 

A. The Present or Threatened 

Destruction, Modification, or 

Curtailment of Its Habitat or Range 

Residential, Urban, and Energy 

Development 

At the time of listing (65 FR 62302; 

October 18, 2000), residential and urban 

development around the cities of 

Cheyenne and Fort Collins were 

identified as past causes of habitat 

conversion and habitat loss to the 

Colorado butterfly plant; these types of 

development were not a concern in 

Nebraska at the time of listing nor are 

they now. Although difficult to quantify 

because land conversion was not 

tracked during the settlement of the 

West, likely a few hundred acres of 

formerly suitable habitat were converted 

to residential and urban sites, 

contributing to loss of habitat (Fertig 

1994, p. 38; Fertig 2000a, pp. 16–17). 

Much of the species’ range occurs along 

the northern Front Range of the Rocky 

Mountains in Colorado and Wyoming, 

which has experienced dramatic growth 

in the recent past and is predicted to 

grow considerably in the future 

(Regional Plan Association 2016, entire), 

particularly in Larimer and Weld 

Counties in Colorado (University of 

Colorado Boulder 2015, pp. 119–120). 

The demand that urban development 

places on water resources also has the 

ability to dewater the streams and lower 

groundwater levels required by the 

species to maintain self-sustaining 

populations, and is explored below. 

The two large populations of the 

Colorado butterfly plant in Larimer and 

Weld Counties, Colorado, occur on 

lands managed as open space by Fort 

Collins, and are not directly subject to 

residential or urban development. 

Consequently, despite projected 

increases in human density and urban 

development along the northern Front 

Range, these lands are managed to allow 

for the persistence of these populations, 

with managed grazing or burning 

(CFCNAD 2016b, entire). Fort Collins 

does not own all mineral rights on these 

lands; therefore, sensitive areas within 

these boundaries may be impacted by 

mineral development. However, in light 

of this potential threat, the city 

completed a planning process in which 

they highlighted areas to be avoided by 

mineral development (The Nature 

Conservancy 2013, entire). While oil 

and gas development has increased in 

northern Colorado and southeastern 

Wyoming since the time of listing, no 

oil or gas wells have been proposed or 

likely will be proposed in areas that will 

directly or indirectly impact 

populations of the Colorado butterfly 

plant in Colorado or in Wyoming, 

particularly due to the species’ 

occurrence in riparian and wetland 

habitats. Because the plant occurs in 

riparian and wetland habitats that 

routinely flood, it is likely that oil and 

gas wells will be sited outside of 

population boundaries. While there is 

potential for indirect effects through 

spills or sedimentation, we have no 

specific information about those effects 

on the species to date. 

According to publicly available 

information, there are no current 

proposals for urban or residential 

development on lands containing 

populations of Colorado butterfly plant 

in Wyoming. Monitoring of lands under 

agreement (CFCNAD, WEAs, and 

Warren AFB) has also shown that 

neither urbanization nor conversion to 

intensive agricultural activities has 

occurred as predicted in the final listing 

rule (65 FR 62302, October 18, 2000; 

USFWS 2012, pp. 11–22; USFWS 2016c, 

entire). Populations at WAFB remained 

stable over the past 29 years without 

being managed for agricultural 

purposes, although numbers of 

reproductive individuals fluctuate 

during any given year (Heidel et al., 

2016, pp. 14–18). Since the time of 

listing, the Service has received few 

requests for consultation under section 

7 of the Act for projects that may 

adversely affect this species. Informal 

consultations have been limited to 

grazing, power lines, pipelines, road 

development, and drainage crossing 

projects, and avoidance and 

minimization of potential impacts has 

been readily achieved (USFWS 2017c, 

entire). 

Furthermore, chapters 3 and 4 of the 

Laramie County Land Use Regulations 

address floodplain management and 

require specific provisions and permits 

for construction within floodplains 

(Laramie County 2011, pp. 165–185), 

which encompass all Colorado butterfly 

plant habitat within the county; these 

regulations, therefore, extend some level 

of protection to the species and its 

habitat. These regulations are in place to 

‘‘promote public health, safety, and 

general welfare and to minimize public 

and private losses due to flood 

conditions’’ (Laramie County 2011, 

p. 165), and protect many resources, 

including the Colorado butterfly plant 

and its habitat, by limiting development 

in the floodplains. These regulations are 

discussed in detail under Factor D, 

below. 

The threats of residential and urban 

development, once considered 

significant threats to the Colorado 

butterfly plant, have been largely 

avoided because most development has 

occurred outside of the habitat in which 

this species occurs. Annual monitoring 

conducted by the Service since 2004 

indicates that populations are stable and 

unaffected by any development that has 

occurred within the species’ range. 

While human population growth and 

development are predicted for the Front 

Range of the Rocky Mountains in 

Colorado into the future, these areas are 

outside of the species’ occupied habitat, 

and we do not anticipate development 

in the protected areas under 

management of Fort Collins, and do not 

anticipate development due to 

continued restrictions against 


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development within the floodplain. 

Additionally, increases in oil and gas 

development in northern Colorado and 

southeastern Wyoming have not directly 

or indirectly impacted populations of 

the Colorado butterfly plant. Current 

ownership and management by Fort 

Collins and Warren AFB of lands 

containing a majority of large 

populations of the Colorado butterfly 

plant protect the species from current 

and future impacts due to residential, 

urban, and energy development. 

Agricultural Practices 

At the time of listing (65 FR 62302; 

October 18, 2000), conversion of 

grassland to farmlands, mowing 

grasslands, and grazing were considered 

threats to the Colorado butterfly plant. 

Prior to listing, the conversion of moist, 

native grasslands to commercial 

croplands was widespread throughout 

much of southeastern Wyoming and 

northeastern Colorado (Compton and 

Hugie 1993, p. 22), as well as in 

Nebraska. However, conversion from 

native grassland to cropland has slowed 

throughout the species’ range since the 

time of listing, with no lands converted 

in Laramie County and just 12 ha (30 ac) 

converted in Platte County between 

2011 and 2012 (FSA 2013, entire). 

Mowing areas for hay production that 

are occupied by the Colorado butterfly 

plant was identified as a threat at the 

time of listing, if conducted at an 

inappropriate time of year (prior to seed 

maturation) (Fertig 1994, p. 40; USFWS 

1997, p. 8). However, monitoring over 

the past 13 years indicates that mowing 

prior to seed maturation occurs 

infrequently. Even in areas where early 

season mowing has occurred, annual 

monitoring has shown high numbers of 

reproductive plants present in 

subsequent years, suggesting that 

mowing for hay production is not a 

threat to the species (USFWS 2016c, 

entire). 

The agricultural practices of grazing 

and herbicide application threatened 

the Colorado butterfly plant at the time 

of listing. However, since then, the 

Service has made and continues to make 

recommendations to cooperating 

landowners on agricultural management 

that fosters resiliency in populations of 

the species. We believe that these 

measures have decreased the severity of 

these stressors. We also anticipate that 

landowners will continue their current 

agricultural practices into the future, 

based on the data we have collected 

from WEAs (USFWS 2016c, entire) and 

analysis of aerial imagery of designated 

critical habitat (USFWS 2017b, entire). 

Through these agreements, we also 

learned that the species is highly 

adapted to withstand stochastic events. 

The assessment that the species is 

highly resilient is based on the 

information obtained through the 

WEAs; we do not rely on the 

implementation of the WEAs to ensure 

that the species remains highly resilient. 

Instead, we believe the plant will 

continue to thrive even if protections 

are removed. Grazing is further explored 

under Factor C, below, and herbicide 

spraying is further explored under 

Factor E, below. 

Water Management 

At the time of listing (65 FR 62302; 

October 18, 2000), water management 

(actions that moved water to croplands, 

such as irrigation canals, diversions, 

and center pivot irrigation development) 

was considered a threat that would 

remove moisture from Colorado 

butterfly plant habitat. The management 

of water resources for livestock 

production and domestic and 

commercial human consumption, 

coupled with increasing conversion of 

lands for agricultural production, often 

led to channelization and isolation of 

water resources; changes in seasonality 

of flow; and fragmentation, realignment, 

and reduction of riparian and moist 

lowland habitat (Compton and Hugie 

1993, p. 22). All of these actions could 

negatively impact suitable habitat for 

the species. 

Dewatering portions of Lodgepole 

Creek in Kimball County, Nebraska, has 

led to the extirpation of some of the 

species’ known historical populations 

there, and low likelihood of long-term 

resiliency for the two extant populations 

last monitored in 2008 (Rabbe 2016, 

pers. comm.). Extant populations in 

Nebraska continue to experience 

dewatering and overgrazing on private 

land. However, when water was 

reintroduced to formerly occupied 

habitat after being absent for more than 

10 years, a population was rediscovered 

(Wooten 2008, p. 4). While rediscovery 

of this population indicates persistence 

of a viable seedbank for at least 10 years, 

numbers of plants within the population 

declined from over 600 plants (Fertig 

2000a, p. 12) to 12 plants (Wooten 2008, 

p. 4), and the application of water that 

allowed plants to grow was temporary, 

which suggests the population has a low 

likelihood of long-term resiliency. 

In 2016, the Colorado Water 

Conservation Board on behalf of Fort 

Collins filed an instream flow right on 

Graves Creek, the stream that feeds the 

population of Colorado butterfly plants 

in Soapstone Prairie (CFCNAD 2016b, 

entire). While the water right has not yet 

been granted, we believe that this 

instream flow right will protect and 

maintain subirrigation of this large and 

important population through ensuring 

adequate water availability to the 

species throughout the year. 

The entire range of the Colorado 

butterfly plant occurs within the Platte 

River Basin. Water usage in the Platte 

River system is managed collaboratively 

by the States of Colorado, Wyoming, 

and Nebraska, and the Department of 

the Interior, through the Platte River 

Recovery Implementation Program 

(PRRIP). The PRRIP, which began in 

1997, provides a mechanism for existing 

and new water users and waterdevelopment activities in the Platte 

River Basin to operate in regulatory 

compliance with the Act regarding 

potential impacts to the five Platte River 

‘‘target species’’ in Nebraska: Grus 

americana (whooping crane), Sterna 

(Sternula) antillarum (interior least 

tern), Charadrius melodus (northern 

Great Plains population of piping 

plover), Scaphirhynchus albus (pallid 

sturgeon), and Platanthera praeclara 

(western prairie fringed orchid). 

Because the PRRIP ensures that 

shortages to the target flows in the 

central Platte River will be substantially 

reduced by keeping water within the 

basin more consistently throughout the 

year (PRRIP 2016), the hydrological 

component of habitat for the Colorado 

butterfly plant will be better maintained 

as well. 

In summary, water management can 

directly and indirectly impact the 

Colorado butterfly plant. While 

management of water resources has 

negatively impacted the species on a 

localized scale in the past, there is no 

indication that water management 

throughout the majority of the species’ 

range poses a current threat to the 

species because programs and policies 

currently in place, such as the PRRIP 

and Graves Creek instream flow right, 

provide substantial assurances that the 

hydrological component of currently 

occupied habitat will remain protected 

over the long term. 

Natural Succession and Competition 

With Nonnative, Invasive Species 

In the absence of periodic 

disturbance, natural succession of the 

plant community in areas occupied by 

the Colorado butterfly plant moves from 

open habitats to dense coverage of 

grasses and forbs, and then to willows 

and other woody species. The semiopen habitats preferred by this species 

can become choked by tall and dense 

growth of willows; grasses; and 

nonnative, invasive species (Fertig 1994, 

p. 19; Fertig 2000a, p. 17). Natural 

disturbances such as flooding, fire, and 

native ungulate grazing were sufficient 


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in the past to create favorable habitat 

conditions for the species. However, the 

natural flooding regime within the 

species’ floodplain habitat has been 

altered by construction of flood control 

structures and by irrigation and 

channelization practices (Compton and 

Hugie 1993, p. 23; Fertig 1994, pp. 39– 

40). Consequently, the species relies on 

an altered flood regime and other 

sources of disturbance to maintain its 

habitat. 

In the absence of natural disturbances 

today, managed disturbance may be 

necessary to maintain and create areas 

of suitable habitat (Fertig 1994, p. 22; 

Fertig 1996, pp. 12–14; Fertig 2000a, p. 

15). However, populations can persist 

without natural disturbances such as 

fire and flooding through natural 

dieback of woody vegetation and native 

ungulate grazing (Heidel et al., 2016, pp. 

2–5). Additionally, some Federal 

programs, such as those administered by 

the U.S. Department of Agriculture’s 

Natural Resources Conservation Service, 

focus on enhancing or protecting 

riparian areas by increasing vegetation 

cover and pushing the habitat into later 

successional stages, which removes the 

types of disturbance the Colorado 

butterfly plant needs (65 FR 62302; 

October 18, 2000, p. 62307). However, 

these programs are implemented in only 

a small portion of the species’ range. 

The Service learned from monitoring 

the 11 WEA properties that the typical 

approach of managing for livestock 

grazing, coupled with an altered flood 

regime, appears to provide the correct 

timing and intensity of disturbance to 

maintain suitable habitat for the species 

(USFWS 2012, pp. 9–21; USFWS 2016c, 

entire). There has been no noticeable 

change in general management practices 

or change in the natural succession rate 

in either the WEA properties or the 

designated critical habitat since the 

agreements were signed or the critical 

habitat was designated, and we have no 

reason to believe that these practices or 

rates will change in the foreseeable 

future. Therefore, through the 

information we have gathered since the 

time of listing, it appears that natural 

succession is not occurring at the level 

previously considered to threaten this 

species. 

The final listing rule (65 FR 62302; 

October 18, 2000) included competition 

with exotic plants and noxious weeds as 

a threat to the Colorado butterfly plant. 

Competition with exotic plants and 

noxious weeds, here referred to as 

nonnative, invasive species, may pose a 

threat to the Colorado butterfly plant, 

particularly given the species’ 

adaptation to more open habitats. In 

areas of suitable habitat for Colorado 

butterfly plant, the following plants may 

become dominant: The native Salix 

exigua (coyote willow); nonnative, 

invasive Cirsium arvense (Canada 

thistle); and nonnative, invasive 

Euphorbia esula (leafy spurge). Salix in 

particular increases in the absence of 

grazing or mowing. These species can 

outcompete and displace the Colorado 

butterfly plant, presumably until 

another disturbance removes competing 

vegetation and creates openings for 

Colorado butterfly plant seedlings to 

germinate (Fertig 1998a, p. 17). Since 

2004, we have monitored populations of 

the Colorado butterfly plant that have 

slowly decreased in numbers or 

disappeared following the invasion and 

establishment of these other plant 

species, only to see Colorado butterfly 

plants return to the area following 

disturbance (USFWS 2016c, entire). 

Additionally, at least one population 

has moved to an uninvaded area 

downstream of its former invaded 

habitat (Handwerk 2016, pers. comm.), 

suggesting that populations can move to 

find more suitable habitat nearby. 

Prior to listing, biological control 

agents were used to control nonnative, 

invasive species at Warren AFB and 

may have depressed numbers and extent 

of Canada thistle and leafy spurge. 

Introduced gall-forming flies have 

slowly become established on Warren 

AFB and have reduced the vigor, height, 

and reproductive ability of small 

patches of Canada thistle (Fertig 1997, 

p. 15), at least in some years (Heidel et 

al., 2016, p. 16). Also on the Warren 

AFB, a biocontrol agent for leafy spurge, 

a different flea beetle than infests the 

Colorado butterfly plant, was observed 

in 1997 (Fertig 1998b, p. 18). While the 

effects of biocontrol agents on 

nonnative, invasive species appear 

promising, we do not have current 

information on the status of biocontrol 

of these agents. 

Natural succession was considered a 

threat to the Colorado butterfly plant at 

the time of listing. However, we now 

understand that the altered flood regime 

of today, coupled with disturbance from 

fire and grazing, is sufficient to maintain 

suitable habitat throughout much of the 

species’ range. Competition with 

nonnative, invasive species is an 

ongoing stressor for portions of 

populations, although these invasive 

species tend not to survive the regular 

disturbances that create habitat for the 

Colorado butterfly plant. Therefore, 

while individuals or populations may 

be out-competed by native or nonnative, 

invasive species at higher succession 

levels, periodic disturbance maintains 

or creates new habitats for the Colorado 

butterfly plant. 

Summary of Factor A 

The following stressors warranted 

consideration as possible current or 

future threats to the Colorado butterfly 

plant habitat under Factor A: (1) 

Residential, urban, and energy 

development; (2) agricultural practices; 

(3) water management; and (4) natural 

succession and competition with 

nonnative, invasive species. However, 

these stressors are either being 

adequately managed, have not occurred 

to the extent anticipated at the time of 

listing, or new information indicates 

that the species is tolerant of the stressor 

as described above. While these 

stressors may be responsible for loss of 

historical populations (they have 

negatively affected population 

redundancy), and are currently 

negatively affecting the populations in 

Nebraska, we do not anticipate a 

rangewide increase in these stressors in 

the future, although they will continue 

at some level. 

B. Overutilization for Commercial, 

Recreational, Scientific, or Educational 

Purposes 

Factor B was not considered a threat 

to the species at the time of listing (65 

FR 62302; October 18, 2000). We are 

aware of three unpermitted collections 

of seeds of the Colorado butterfly plant 

for scientific and/or commercial 

purposes since the publication of the 

final listing rule. These three collections 

were limited events that occurred at an 

introduction site in Colorado and from 

a large, robust population in Wyoming. 

Based on recent population data, these 

unpermitted collection events had no 

apparent impact on the number and 

distribution of plants within these 

populations or the species’ habitat 

(based on Heidel et al., 2016, p. 13; 

USFWS 2016c, entire). Other than these 

collections, we are not aware of any 

attempts to use the Colorado butterfly 

plant for commercial, recreational, 

scientific, or educational purposes. In 

the future, we do not anticipate this 

species will be collected due to its lack 

of showiness for much of the year and 

because it occurs in generally 

inaccessible areas. 

Summary of Factor B 

At the time of listing, Factor B was 

not considered a threat to the Colorado 

butterfly plant. We are aware of only 

three unpermitted collections of the 

seeds of the species since listing. These 

collection events had no apparent effect 

on the number and distribution of 

plants from which they were taken. 

Based on available information, we do 

not consider there to be threats now or 


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in the future related to overutilization 

for commercial, recreational, scientific, 

or educational purposes. 

C. Disease or Predation 

The listing of the Colorado butterfly 

plant (65 FR 62302; October 18, 2000) 

did not include threats from disease or 

predation, although livestock grazing 

was described as a potential threat if 

grazing pressures were high. No 

diseases are known to affect this 

species. In 2007, a precipitous decline 

in plant numbers was observed in many 

populations monitored in Colorado and 

Wyoming. The exact cause of the 

decline was not positively identified, 

but weather and insect herbivory were 

two potential contributing factors. 

Weather-related impacts included an 

early start to the growing season, lower 

than normal spring precipitation levels 

(which were magnitudes lower than in 

all previous years), and higher mean 

temperatures in late summer. Insect 

herbivory also was suspected, as 

virtually all reproductive plants were 

riddled with holes, flowering and fruit 

production was curtailed or greatly 

reduced on all plants, and some bolted 

plants died before flowering. 

Interestingly, no vegetative (i.e., nonreproductive) plants showed similar 

evidence of herbivory (Heidel et al., 

2011, pp. 284–285). Flowering plant 

numbers remained low or declined 

further in 2008. Surveyors identified 

one or more flea beetle species that may 

have been responsible for the herbivory. 

The likely flea beetle species (Altica 

foliaceae) is a native species, and its 

numbers are not known to be affected by 

human causes. 

Insect herbivory may not be a severe 

or immediate threat to Colorado or 

Wyoming populations as the abovereferenced impacted populations 

rebounded to pre-infestation numbers in 

2009 and 2010 (Heidel et al., 2011, p. 

286). However, insect herbivory may be 

episodic and potentially tied to climate; 

preliminary tests have been conducted 

on its potential impact on population 

resiliency (Heidel et al., 2011, p. 286). 

For example, in 2014, intense herbivory 

from flea beetles at Soapstone Prairie 

and Meadow Springs Ranch resulted in 

high mortality and a reduction in 

bolting of vegetative rosettes (Strouse 

2017, pers. comm.), and numbers of 

reproductive individuals in those 

populations were low in 2015 and 2016. 

We found that these populations 

rebounded in 2017 to record numbers, 

in the same way populations rebounded 

after the 2007 flea-beetle-caused 

decline. This herbivory has not been 

reported for the Nebraska populations, 

although it is possible that similar insect 

herbivory influenced 2008 survey 

results in Nebraska. 

Colorado butterfly plant is highly 

palatable to a variety of insect and 

mammalian herbivores including Gaura 

moth (Schinia gaura), cattle, horses, and 

pronghorn (Antilocapra americana), but 

the plant appears to have some capacity 

to compensate for herbivory by 

increasing branch and fruit production 

(Fertig 1994, p. 6; Fertig 2000a, p. 17). 

Livestock grazing can be a threat at 

some sites if grazing pressures are high 

or if use is concentrated during the 

summer flowering and fruiting period. 

Additionally, plants may be 

occasionally uprooted or trampled by 

livestock and wildlife. In at least two 

locations where a population was 

divided by a fence, the heavily grazed 

side of the fence had few or no Colorado 

butterfly plants, while the ungrazed side 

had many (Marriott 1987, p. 27; USFWS 

2016c, entire). 

Heavy grazing at key times of the year 

during the life cycle of the Colorado 

butterfly plant may be detrimental to 

populations by temporarily removing 

reproductive individuals and 

eliminating seed production for that 

year. However, even after many years of 

intensive grazing, populations 

rebounded upon relief (USFWS 2012, 

pp. 11–21; USFWS 2016c, entire). This 

response is likely due to survival of 

non-reproductive individuals and 

recruitment from the seedbank. 

Moderate grazing acts as a disturbance 

that keeps the habitat in an open or 

semi-open state suitable for this species, 

and light to medium grazing can 

provide benefits by reducing the 

competing vegetative cover and 

allowing seedlings to become 

established (USFWS 1997, p. 8). 

Summary of Factor C 

In general, while disease or predation 

has had an occasional negative impact 

on individuals and localities, most of 

these impacts do not appear to affect 

entire populations, nor do these impacts 

persist for any extended period of time. 

Individuals are resilient to damage; 

vegetative plants (basal rosettes) appear 

to be resistant to damage from grazing 

activities and are capable of 

withstanding stochastic events, and 

reproductive plants send out additional 

flowering branches upon injury. Also, 

the lack of any known diseases affecting 

the species and the species’ redundancy 

of many populations distributed across 

most of the historical range would likely 

provide a buffer to any type of 

catastrophic disease outbreak. 

D. The Inadequacy of Existing 

Regulatory Mechanisms 

Under this factor, we examine 

whether the stressors identified within 

the other factors may be ameliorated or 

exacerbated by an existing regulatory 

mechanism. Section 4(b)(1)(A) of the 

Act requires the Service to take into 

account ‘‘those efforts, if any, being 

made by any State or foreign nation, or 

any political subdivision of a State or 

foreign nation, to protect such species.’’ 

In relation to Factor D under the Act, we 

interpret this language to require the 

Service to consider relevant Federal, 

State, and Tribal laws, regulations, and 

other such binding legal mechanisms 

that may ameliorate or exacerbate any of 

the threats we describe in threats 

analyses under the other four factors, or 

otherwise enhance conservation of the 

species. Our consideration of these 

mechanisms is described in detail 

within our analysis of each of the factors 

(see discussion under each of the other 

factors). 

For currently listed species, we 

consider the adequacy of existing 

regulatory mechanisms to address 

threats to the species absent the 

protections of the Act. Therefore, we 

examine whether other regulatory 

mechanisms would remain in place if 

the species were delisted, and the extent 

to which those mechanisms will 

continue to help ensure that future 

threats will be reduced or minimized. 

In our discussion under Factors A, B, 

C, and E, we evaluate the significance of 

threats as mitigated by any conservation 

efforts and existing regulatory 

mechanisms. Where threats exist, we 

analyze the extent to which 

conservation measures and existing 

regulatory mechanisms address the 

specific threats to the species. 

Regulatory mechanisms, if they exist, 

may reduce or eliminate the impacts 

from one or more identified threats. 

Presently, the Colorado butterfly plant is 

a Tier 1 species in the Plants of Greatest 

Conservation Need in Colorado 

(Colorado SWAP 2015, entire), and the 

species is listed on the State endangered 

species list for Nebraska, and will 

continue to be so designated due to the 

species’ extreme rarity in Nebraska 

(Wooten 2008, p. 1). 

When we listed the Colorado butterfly 

plant in 2000 (65 FR 62302; October 18, 

2000), the majority of known 

populations occurred on private lands 

managed primarily for agriculture, with 

one population at Warren AFB, and a 

few other populations throughout the 

species’ range under various local 

jurisdictions. The listing decision 

described the species’ status as 


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Sensitive by the U.S. Forest Service, 

although no populations occurred on 

Forest Service lands at the time. The 

listing decision also described the lack 

of protection extended to the Colorado 

butterfly plant through the Federal 

threatened status of Zapus hudsonius 

preblei (Preble’s meadow jumping 

mouse) that occurs in the same range of 

habitats due to the two species’ use of 

differing successional stages of riparian 

habitats (65 FR 62302; October 18, 

2000). 

Today, the population on Warren AFB 

represents one of the largest and most 

highly resilient populations of the 

species, is managed under an integrated 

natural resources management plan 

(Warren AFB 2014, entire) and a 

conservation and management plan 

under Air Force Information 32–7064 

(Warren AFB 2004, entire). These plans 

call for annual monitoring, protection 

and maintenance, and research on 

threats and genetic variability of the 

population located there. Additionally, 

a Service employee stationed at Warren 

AFB manages its natural resources, 

including management of the Colorado 

butterfly plant and its habitat, such as 

directing the application of herbicide in 

the vicinity of the species’ habitat. 

These plans would remain postdelisting. The population of the 

Colorado butterfly plant at Warren AFB 

has been monitored since before listing 

to determine population trends, detect 

any changes in its habitat, pursue 

viability assessment, and assess 

population response to different 

hydrological conditions. The results 

indicate that plant numbers fluctuate 

depending on climate and hydrology, 

and seem to be capable of rebounding 

after extreme stochastic events such as 

the flea beetle infestation of 2007 

(Heidel et al., 2016, pp. 15–17). Should 

the protections of the Act be removed 

from this species upon delisting, the 

aforementioned plans would remain in 

place, at least until the next plan 

revisions, which have yet to be 

scheduled. 

Discovery and subsequent protection 

of large populations of the Colorado 

butterfly plant on lands owned and 

managed by Fort Collins are an 

important addition to conservation of 

the species after it was listed in 2000. 

The regulatory protections that these 

two populations receive from occurring 

on municipal natural areas lands 

include indefinite protections of land 

and water and restoring and 

rehabilitating land and natural systems 

to build ecological diversity and 

permanence (City of Fort Collins 2014, 

pp. 1–2). Populations managed by Fort 

Collins are afforded protection from oil 

and gas development (The Nature 

Conservancy 2013, entire) and from 

water withdrawals (CFCNAD 2016b, 

entire), as discussed above under Factor 

A. Also, as mentioned in ‘‘Residential, 

Urban, and Energy Development’’ under 

Factor A, the Laramie County Land Use 

Regulations address floodplain 

management and require specific 

provisions and permits for construction 

within floodplains (Laramie County 

2011, pp. 165–185), which encompass 

all Colorado butterfly plant habitat 

within the county; therefore, these 

regulations extend some level of 

protection to the species and its habitat. 

While protecting riparian and wetland 

species is not the intent of these 

regulations, plants growing within the 

floodplain receive the habitat 

protections outlined as part of the 

floodplain construction avoidance 

provisions. 

Lands without specific regulatory 

mechanisms contain most populations 

of the Colorado butterfly plant. Over a 

decade of monitoring 11 occurrences on 

private lands in Wyoming has 

documented fluctuations in population 

size about a stable mean, apparently 

driven by changes in precipitation and 

disturbance regime (USFWS 2012, pp. 

11–22; USFWS 2016c, entire). 

Management of lands under WEAs is 

discussed in Conservation Efforts, 

above. 

Populations of Colorado butterfly 

plant are not known to occur on lands 

managed by the Bureau of Land 

Management (BLM) at this time, 

although there is potential for 

populations to be discovered on BLM 

lands in the future. Because of this 

possibility, the Service and BLM in 

Wyoming have developed conservation 

measures under a Statewide 

programmatic consultation under 

section 7 of the Act for the Colorado 

butterfly plant. These conservation 

measures are incorporated into BLM’s 

2008 Record of Decision and Approved 

Rawlins Resource Management Plan 

(RMP; BLM 2008, entire) and include, 

but are not limited to: (1) Buffering 

individuals and populations by 800 m 

(0.5 mi); (2) implementing standards for 

healthy rangelands and guidelines for 

livestock grazing management for the 

public lands administered by BLM in 

the State of Wyoming; (3) limiting the 

number of grazing animals within the 

permit area; and (4) protecting surface 

water through prohibiting surface 

development in the following areas: 

Within 400 m (0.25 mi) of the North 

Platte River; within 152 m (500 ft) of 

live streams, lakes, reservoirs, and 

canals and associated riparian habitat; 

and within 152 m (500 ft) of water 

wells, springs, or artesian and flowing 

wells (BLM 2005, pp. 4–2 through 4–4). 

The newly discovered population on 

Wild Horse Creek (WY–23) occurs 

within the agreement area that BLM 

developed with the landowners, and so 

the conservation measures included in 

the Rawlins RMP are applied to this 

population. 

Water use is managed under the 

PRRIP, as described above under Factor 

A, which ensures that water use in the 

Platte River is conducted in a way to 

maintain volume at certain times of the 

year in the central and lower reaches of 

the Platte River in Nebraska. Because all 

of the watersheds in which the Colorado 

butterfly plant is found occur within the 

PRRIP, the water on which the species 

depends is managed under this program 

(PRRIP 2006). The water that this 

species requires would continue to be 

included under the PRRIP even if the 

Colorado butterfly plant is removed 

from the List of Threatened and 

Endangered Plants. 

Summary of Factor D 

At the time of listing (65 FR 62302; 

October 18, 2000), no Federal or State 

laws or regulations specifically 

protected populations of the Colorado 

butterfly plant and its habitat. However, 

two of the three largest populations 

occur on Warren AFB and lands owned 

and managed for the species by Fort 

Collins where regulatory mechanisms 

now exist. Additionally, 13 years of 

annual monitoring of 11 survey areas on 

private lands under WEAs that has 

occurred since the species was listed 

has shown that land used for 

agricultural purposes can be compatible 

with the resilience of the species, even 

without any regulatory mechanism in 

place (see discussions under Factors A, 

C, and E). Consequently, we find that 

existing regulatory mechanisms, as 

discussed above, will continue to 

address stressors to the Colorado 

butterfly plant absent protections under 

the Act. 

E. Other Natural or Manmade Factors 

Affecting Its Continued Existence 

Factor E requires the Service to 

consider any other factors that may be 

affecting the Colorado butterfly plant. 

Under this factor, we discuss small 

population size and restricted range, 

herbicide spraying, and effects of 

climate change. 

Small Population Size and Restricted 

Range 

The final listing decision (65 FR 

62302; October 18, 2000) included the 

limited range and the small population 

size of many populations to be a threat 


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to the Colorado butterfly plant. 

However, small population size and a 

restricted range is not a threat in and of 

itself. Historically, Colorado butterfly 

plant populations occurred from Castle 

Rock, Colorado, north to Chugwater, 

Wyoming, and east into a small portion 

of southwest Nebraska. The extent of its 

range was approximately 6,880 ha 

(17,000 ac). Most of this range is still 

occupied, although some small and/or 

peripheral populations in Nebraska and 

Colorado have been extirpated since 

intensive survey efforts began. Despite 

the loss of these populations, the 

species continues to maintain multiple 

resilient, representative, and redundant 

populations throughout nearly all of its 

range known at the time of listing (see 

figure, above). 

We have evidence that populations 

throughout the range have persisted 

despite stochastic events that may have 

caused short-term declines in number of 

individuals. For example, a 100-year 

flood in August 1985 on the Warren 

AFB inundated the Crow Creek portion 

of the population, knocking down some 

plants and surrounding vegetation, and 

depositing sediments (Rocky Mountain 

Heritage Task Force 1987, as cited in 

Heidel et al., 2016, p. 2). Instead of 

being extirpated, these populations 

rebounded in 1986 and continue to 

persist (summarized in Heidel et al., 

2016, pp. 2–18). Additionally, based on 

annual monitoring of populations on 

private property in Wyoming, stochastic 

events such as floods and hail storms 

have reduced population numbers 

during the event year, then populations 

rebounded in following years (USFWS 

2012, pp. 11–22; USFWS 2016c, entire). 

Individual plants may be vulnerable to 

random events such as fires, insect or 

disease outbreaks, or other 

unpredictable events. However, this 

species is adapted to disturbance, and 

rather than being extirpated, the 

seedbank can provide opportunity for 

populations to rebound after such 

events. 

The historical range included 

populations farther south into Larimer 

and Weld Counties in Colorado that 

were lost prior to the listing of the 

species in 2000. No populations in 

Larimer and Weld Counties in Colorado 

have been extirpated since the species 

was listed, and we do not think that 

further range restriction has occurred in 

this portion of the species’ range. In the 

future, species range restriction may 

occur through loss of peripheral 

populations in Nebraska where 

dewatering has removed formerly 

suitable habitat (Wooten 2008, entire). 

However, these populations are 

downstream of highly viable 

populations in Wyoming, and do not 

constitute a removal of the species from 

this drainage entirely. The resiliency 

and redundancy of populations across 

much of the species’ range indicate that 

further range restriction is not likely. 

Herbicide Spraying 

At the time of listing (65 FR 62302; 

October 18, 2000), the non-selective use 

of broadleaf herbicides to control 

Canada thistle, leafy spurge, and other 

nonnative, invasive plants was 

considered a threat to the Colorado 

butterfly plant. Non-selective spraying 

has had negative effects on some 

Colorado butterfly plant populations 

(Fertig 2000a, p. 16). For example, in 

1983, which was prior to listing, nearly 

one-half of the mapped population on 

Warren AFB was inadvertently 

destroyed when sprayed with Tordon®, 

a persistent herbicide (Miller 1987, as 

cited in 65 FR 62302, October 18, 2000, 

p. 62307). The status of that portion of 

the population is unknown due to a 

subsequent lack of clear record-keeping 

at that time, prior to a Service biologist 

being employed on site; all plant 

locations have been tracked in the time 

after the Service biologist and Wyoming 

Natural Diversity Database began 

working at Warren AFB. Herbicide use 

along road crossings in and adjacent to 

plant populations was also noted (65 FR 

62302, October 18, 2000, p. 62307). 

After the 2000 listing of the Colorado 

butterfly plant, the Service worked with 

Warren AFB and private landowners 

under WEAs to develop best 

management practices for applying 

herbicides within the vicinity of known 

occurrences to remove nonnative, 

invasive species while minimizing 

adverse effects to individual Colorado 

butterfly plants. For example, the WEAs 

require an herbicide-application buffer 

of 30.5 m (100 ft) from known locations 

of the Colorado butterfly plant. 

However, at one property, the 

landowner inadvertently sprayed 

individual plants in spring 2016. During 

subsequent monitoring, Service staff 

observed reddened plants with 

shriveled leaves, which likely reduced 

the vigor of those individuals (USFWS 

2016c, entire). We presume that there 

will be no long-term effects on the 

population, and in fact, we found 

vigorous Colorado butterfly plants 

growing in this area during surveys in 

2017. Furthermore, if the species is 

delisted, we anticipate that landowners 

will continue to maintain this buffer in 

accordance with requirements under the 

WEAs and that Warren AFB will 

continue to avoid spraying herbicide in 

the vicinity of the species’ habitat as 

stipulated in their integrated natural 

resources management plan and 

conservation and management plan. 

While herbicide application may 

continue to occasionally occur within 

Colorado butterfly habitat, we know that 

unsprayed individuals persist in the 

population and can repopulate Colorado 

butterfly plants in areas where plants 

were killed. The seedbank can play an 

additional role in restoring Colorado 

butterfly plants to areas that have been 

sprayed. Based on our records, 

herbicide application is a management 

tool used in conjunction with 

nonnative, invasive species removal in 

only four of the known occurrences of 

the species, and these are among our 

largest and most resilient populations of 

the species. Our records indicate that, in 

general, application of buffers has been 

successful at reducing the presence of 

invasive species and competition near 

the Colorado butterfly plant (USFWS 

2012, pp. 24–25; USFWS 2016c, entire), 

and when conducted appropriately, 

herbicide application can help improve 

habitat for the Colorado butterfly plant 

by eliminating competition. 

Effects of Climate Change 

Impacts from climate change were not 

considered in the final rule to list the 

species (65 FR 62302; October 18, 2000) 

or in the critical habitat designation (70 

FR 1940; January 11, 2005). Our current 

analyses under the Act include 

consideration of ongoing and projected 

changes in climate. The terms ‘‘climate’’ 

and ‘‘climate change’’ are defined by the 

Intergovernmental Panel on Climate 

Change (IPCC). ‘‘Climate’’ refers to the 

mean and variability of different types 

of weather conditions over time, with 30 

years being a typical period for such 

measurements, although shorter or 

longer periods also may be used (IPCC 

2007, p. 78). The term ‘‘climate change’’ 

thus refers to a change in the mean or 

variability of one or more measures of 

climate (e.g., temperature or 

precipitation) that persists for an 

extended period, typically decades or 

longer, whether the change is due to 

natural variability, human activity, or 

both (IPCC 2007, p. 78). Various types 

of changes in climate can have direct or 

indirect effects on species. These effects 

may be positive, neutral, or negative and 

they may change over time, depending 

on the species and other relevant 

considerations, such as the effects of 

interactions of climate with other 

variables (e.g., habitat fragmentation) 

(IPCC 2007, pp. 8–14, 18–19). In our 

analyses, we use our expert judgment to 

weigh relevant information, including 

uncertainty, in our consideration of 

various aspects of climate change. 


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According to IPCC, ‘‘most plant 

species cannot naturally shift their 

geographical ranges sufficiently fast to 

keep up with current and high projected 

rates of climate change on most 

landscapes’’ (IPCC 2014, p. 13). Plant 

species with restricted ranges may 

experience population declines as a 

result of the effects of climate change. 

The concept of changing climate can be 

meaningfully assessed both by looking 

into the future and reviewing past 

changes. A review of Wyoming climate 

since 1895 indicates that there has been 

a significant increase in the frequency of 

warmer-than-normal years, an increase 

in temperatures throughout all regions 

of the State, and a decline in the 

frequency of ‘‘wet’’ winters (Shumann 

2011). Data from the Cheyenne area over 

the past 30 years indicate a rise in 

spring temperatures (Heidel et al. 2016). 

The current climate in Colorado 

butterfly plant habitat is quite variable, 

with annual precipitation ranging from 

25–50 cm (10–20 in) of rain and 81–275 

cm (32–108 in) of snow per year near 

the center of the species’ range at 

Cheyenne Municipal Airport (NOAA 

2016, entire). The years 2000 through 

2006 appeared to have lower than 

average precipitation (NOAA 2016, 

entire), which may have affected the 

ability of plants to withstand flea beetle 

outbreak in 2007 (Heidel et al. 2011, p. 

286). The Colorado butterfly plant is 

semelparous (individual plants are first 

vegetative, then flower and fruit, and 

then die). Therefore, individuals are 

likely capable of remaining in a 

vegetative state under some conditions 

and duration until suitable flowering 

conditions exist, suggesting that the 

species is adapted to variability in the 

amount and timing of precipitation. 

Climate change may affect the timing 

and amount of precipitation as well as 

other factors linked to habitat 

conditions for the Colorado butterfly 

plant. For example, climate models 

predict that by 2050, watersheds 

containing the species will become 

warmer for all four seasons, 

precipitation will increase in the winter, 

and remain about the same in spring, 

summer, and fall (USGS 2016, pp. 1–3). 

Snow water equivalent will decrease in 

winter and spring, and soil water 

storage will decrease in all four seasons 

(USGS 2016, pp. 4–5). Modeling 

predicts an increase in winter 

precipitation, but decreases in soil water 

storage will mean less water for 

subirrigation of the species’ habitat. 

This may mean a shorter window for 

seed germination, lower seed 

production, and potentially increased 

years at the rosette stage to obtain 

sufficient resources to bolt and flower. 

However, we also understand that C3

plants (plants which combine water, 

sugar, and carbon dioxide in carbon 

fixation), including this species, have a 

41 percent proportional increase in 

growth resulting from a 100 percent 

increase in carbon dioxide (Poorter 

1993, p. 77). This increase in growth 

rate due to higher carbon dioxide may 

counteract the need to spend more time 

in the vegetative portion of the life cycle 

in response to climate change. 

Additionally, monitoring indicates that 

populations are able to withstand 

several consecutive years of poor 

growing conditions, and still rebound 

with suitable conditions (USFWS 2012, 

pp. 11–22; USFWS 2016c, entire). 

Climate change has the potential to 

affect the species and its habitat if flea 

beetle outbreaks are fostered or if 

flowering levels are suppressed. 

Although we lack scientific certainty 

regarding what those changes may 

ultimately mean for the species, we 

expect that the species’ current 

adaptations to cope with climate 

variability will mitigate the impact on 

population persistence. 

Summary of Factor E 

Under this factor, we discussed the 

Colorado butterfly plant’s small 

population size and restricted range, 

herbicide spraying, and climate change. 

In 2000, when we listed the species, 

the stochastic extirpation of individual 

populations suggested that the range of 

the species might be declining. Despite 

the fact that some populations in 

Colorado, Wyoming, and Nebraska were 

extirpated prior to listing, and others in 

Nebraska were extirpated after listing, 

four additional populations have been 

discovered, two of which are protected, 

and there are still representative and 

redundant populations occurring 

throughout the range of the species. 

Further, individuals and populations 

are resilient to a single herbicide 

application, and have been shown to 

survive or bounce back from such 

events. Education of landowners has 

greatly reduced the indiscriminate 

application of herbicides near 

populations of the Colorado butterfly 

plant. Finally, while climate change 

presents a largely unknown potential 

stressor to the species, individual plants 

are capable of deferring the reproductive 

stage until suitable conditions are 

available, populations are made up of 

individuals found in a range of 

microhabitats, and populations are 

located within various ecological 

settings within the species’ range. This 

indicates that the resiliency, 

redundancy, and representation of 

populations will maintain the species in 

the face of climate change. 

Combination of Factors 

Many of the stressors discussed in 

this analysis could work in concert with 

each other and result in a cumulative 

adverse effect to the Colorado butterfly 

plant, e.g., one stressor may make the 

species more vulnerable to other threats. 

For example, stressors discussed under 

Factor A that individually do not rise to 

the level of a threat could together result 

in habitat loss. Similarly, small 

population size and a restricted range in 

combination with stressors discussed 

under Factor A could present a potential 

concern. However, most of the potential 

stressors we identified either have not 

occurred to the extent originally 

anticipated at the time of listing or are 

adequately managed as described in this 

proposal to delist the species. 

Furthermore, those stressors that are 

evident, such as climate change and 

grazing, appear well-tolerated by the 

species. In addition, for the reasons 

discussed in this proposed rule, we do 

not anticipate stressors to increase on 

lands that afford protections to the 

species (Warren AFB and CFCNAD 

lands) where many of the largest 

populations occur. Furthermore, the 

increases documented in the number 

and size of many populations since the 

species was listed do not indicate that 

cumulative effects of various activities 

and stressors are affecting the viability 

of the species at this time or into the 

future. 

Proposed Determination of Species 

Status 

Section 4 of the Act (16 U.S.C. 1533), 

and its implementing regulations at 50 

CFR part 424, set forth the procedures 

for determining whether a species is an 

endangered species or threatened 

species and should be included on the 

Federal Lists of Endangered and 

Threatened Wildlife and Plants (listed). 

The Act defines an endangered species 

as any species that is ‘‘in danger of 

extinction throughout all or a significant 

portion of its range’’ and a threatened 

species as any species that is ‘‘likely to 

become an endangered species within 

the foreseeable future throughout all or 

a significant portion of its range.’’ We 

may delist a species according to 50 

CFR 424.11(d) if the best available 

scientific and commercial data indicate 

that the species is neither endangered or 

threatened for the following reasons: (1) 

The species is extinct; (2) the species 

has recovered and is no longer 

endangered or threatened; and/or (3) the 

original scientific data used at the time 

the species was classified were in error. 


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Determination of Status Throughout All 

of the Colorado Butterfly Plant’s Range 

We have carefully assessed the best 

scientific and commercial information 

available regarding the past, present, 

and future threats to the Colorado 

butterfly plant. We examined the status 

of the species based on the 2010 

Colorado butterfly plant recovery 

outline (USFWS 2010, entire). We also 

consulted with species experts and land 

management staff with Fort Collins and 

Warren AFB who are actively managing 

for the conservation of the Colorado 

butterfly plant. 

The 2010 Colorado butterfly plant 

recovery outline presented a recovery 

vision for the species in which the 

primary focus was protection of existing 

populations, threats abatement, and 

research (USFWS 2010, entire). The 

initial action plan focused on protection 

of existing populations through 

partnerships with Warren AFB, Fort 

Collins, and private landowners, 

followed by developing a recovery plan 

that would contain objective, 

measurable recovery criteria which, 

when met, would indicate that the 

species could be removed from the 

Federal List of Endangered and 

Threatened Plants. In 2016, the 

Service’s Wyoming Ecological Services 

Field Office began development of a 

recovery plan for the Colorado butterfly 

plant. In reviewing information 

regarding population numbers and 

trends, as well as threats, it appeared 

that most monitored extant populations 

were doing well. Threats named at the 

time of listing were either affecting the 

species at low levels, likely due to 

management actions to recover the 

species, or not affecting the species at 

all, as was observed in preparing the 

2012 5-year status review (USFWS 2012, 

entire). Therefore, the Service 

conducted an assessment of the status of 

the species and whether it should 

remain on the List of Endangered and 

Threatened Plants under the Act. 

We carefully assessed the best 

scientific and commercial information 

available regarding the past, present, 

and future threats to the Colorado 

butterfly plant. We considered all of the 

stressors identified at the time of listing 

in 2000, as well as newly identified 

potential stressors such as oil and gas 

energy development and the effects of 

climate change. The stressors 

considered in our five-factor analysis 

(discussed in detail above under 

Summary of Factors Affecting the 

Species) fall into one or more of the 

following categories: 

• Minimized or mitigated: The 

following stressors are adequately 

managed, and existing information 

indicates that this will not change in the 

future: Residential, urban, and energy 

development; agricultural practices; 

water management; overutilization; and 

herbicide spraying. 

• Avoided: The following stressor has 

not occurred to the extent anticipated at 

the time of listing, and existing 

information indicates that this will not 

change in the future: Restricted range. 

• Tolerated: The species is tolerant of 

the following stressors, and existing 

information indicates that this will not 

change in the future: Natural succession 

and competition with nonnative, 

invasive species; disease and predation; 

and climate change. 

These conclusions are supported by 

the available information regarding the 

species’ abundance, distribution, and 

trends, and are in agreement with 

conclusions presented in our 2010 

recovery outline (USFWS 2010, entire) 

and in our 5-year review (USFWS 2012, 

entire). Thus, after assessing the best 

available information, we conclude that 

the Colorado butterfly plant is not in 

danger of extinction, nor is it likely to 

become so in the foreseeable future. 

Determination of Status Throughout a 

Significant Portion of the Colorado 

Butterfly Plant’s Range 

Under the Act and our implementing 

regulations, a species may warrant 

listing if it is an endangered or a 

threatened species throughout all or a 

significant portion of its range. The Act 

defines ‘‘endangered species’’ as any 

species which is ‘‘in danger of 

extinction throughout all or a significant 

portion of its range,’’ and ‘‘threatened 

species’’ as any species which is ‘‘likely 

to become an endangered species within 

the foreseeable future throughout all or 

a significant portion of its range.’’ The 

term ‘‘species’’ includes ‘‘any 

subspecies of fish or wildlife or plants, 

and any distinct population segment 

[DPS] of any species of vertebrate fish or 

wildlife which interbreeds when 

mature.’’ We published a final policy 

interpretating the phrase ‘‘Significant 

Portion of its Range’’ (SPR) (79 FR 

37578). The final policy states that (1) 

if a species is found to be an endangered 

or a threatened species throughout a 

significant portion of its range, the 

entire species is listed as an endangered 

or a threatened species, respectively, 

and the Act’s protections apply to all 

individuals of the species wherever 

found; (2) a portion of the range of a 

species is ‘‘significant’’ if the species is 

not currently an endangered or a 

threatened species throughout all of its 

range, but the portion’s contribution to 

the viability of the species is so 

important that, without the members in 

that portion, the species would be in 

danger of extinction, or likely to become 

so in the foreseeable future, throughout 

all of its range; (3) the range of a species 

is considered to be the general 

geographical area within which that 

species can be found at the time FWS 

or NMFS makes any particular status 

determination; and (4) if a vertebrate 

species is an endangered or a threatened 

species throughout an SPR, and the 

population in that significant portion is 

a valid DPS, we will list the DPS rather 

than the entire taxonomic species or 

subspecies. 

The SPR policy is applied to all status 

determinations, including analyses for 

the purposes of making listing, 

delisting, and reclassification 

determinations. The procedure for 

analyzing whether any portion is an 

SPR is similar, regardless of the type of 

status determination we are making. 

The first step in our analysis of the 

status of a species is to determine its 

status throughout all of its range. If we 

determine that the species is in danger 

of extinction, or likely to become so in 

the foreseeable future, throughout all of 

its range, we list the species as an 

endangered (or threatened) species and 

no SPR analysis will be required. If the 

species is neither an endangered nor a 

threatened species throughout all of its 

range, we determine whether the 

species is an endangered or a threatened 

species throughout a significant portion 

of its range. If it is, we list the species 

as an endangered or a threatened 

species, respectively; if it is not, we 

conclude that listing the species is not 

warranted. 

When we conduct an SPR analysis, 

we first identify any portions of the 

species’ range that warrant further 

consideration. The range of a species 

can theoretically be divided into 

portions in an infinite number of ways. 

However, there is no purpose to 

analyzing portions of the range that are 

not reasonably likely to be significant 

and either an endangered or a 

threatened species. To identify only 

those portions that warrant further 

consideration, we determine whether 

there is substantial information 

indicating that (1) the portions may be 

significant and (2) the species may be in 

danger of extinction in those portions or 

likely to become so within the 

foreseeable future. We emphasize that 

answering these questions in the 

affirmative is not a determination that 

the species is an endangered or a 

threatened species throughout a 

significant portion of its range—rather, 

it is a step in determining whether a 

more detailed analysis of the issue is 


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required. In practice, a key part of this 

analysis is whether the threats are 

geographically concentrated in some 

way. If the threats to the species are 

affecting it uniformly throughout its 

range, no portion is likely to warrant 

further consideration. Moreover, if any 

concentration of threats apply only to 

portions of the range that clearly do not 

meet the biologically based definition of 

‘‘significant’’ (i.e., the loss of that 

portion clearly would not be expected to 

increase the vulnerability to extinction 

of the entire species), those portions 

will not warrant further consideration. 

If we identify any portions that may 

be both (1) significant and (2) 

endangered or threatened, we engage in 

a more detailed analysis to determine 

whether these standards are indeed met. 

The identification of an SPR does not 

create a presumption, prejudgment, or 

other determination as to whether the 

species in that identified SPR is an 

endangered or a threatened species. We 

must go through a separate analysis to 

determine whether the species is an 

endangered or a threatened species in 

the SPR. To determine whether a 

species is an endangered or a threatened 

species throughout an SPR, we will use 

the same standards and methodology 

that we use to determine if a species is 

an endangered or a threatened species 

throughout its range. 

Depending on the biology of the 

species, its range, and the threats it 

faces, it may be more efficient to address 

the ‘‘significant’’ question first, or the 

status question first. Thus, if we 

determine that a portion of the range is 

not ‘‘significant,’’ we do not need to 

determine whether the species is an 

endangered or a threatened species 

there; if we determine that the species 

is not an endangered or a threatened 

species in a portion of its range, we do 

not need to determine if that portion is 

‘‘significant.’’ 

We evaluated the range of the 

Colorado butterfly plant to determine if 

any area could be considered a 

significant portion of its range. The only 

portion of the range where threats are 

geographically concentrated are the 

three populations in Nebraska. Grazing 

and water management, particularly the 

dewatering of Lodgepole Creek 

downstream of the Wyoming/Nebraska 

border in the three populations in 

Nebraska, has proven to impact 

populations in that portion of the 

species’ range. This stressor has affected 

these populations to a level that the 

populations were presumed extirpated 

at the time we designated critical habitat 

for this species (70 FR 1940; January 11, 

2005). However, after water was 

reintroduced to the creek by a 

landowner, Colorado butterfly plants 

were again observed in Lodgepole Creek 

(Wooten 2008, p. 4). It is possible that 

the species only occurs in this portion 

of its range during times of adequate 

subirrigation and surface flows, and that 

seeds either remain dormant at this 

location for several years or are 

transported from neighboring 

populations located upstream on 

Lodgepole Creek in Wyoming. 

Nevertheless, the removal of water from 

Lodgepole Creek impacts populations of 

the Colorado butterfly plant within this 

portion of the species’ range. 

Because we identified an area on the 

periphery of the species’ current range 

as warranting further consideration due 

to the geographic concentration of 

threats from water management, we 

then evaluated whether this area may be 

significant to the Colorado butterfly 

plant such that, without the members in 

that portion, the entire species would be 

in danger of extinction, or likely to 

become so in the foreseeable future, 

throughout all of its range. We can 

accomplish this by considering the 

viability of the remainder of the range 

without the portion and the biological 

or conservation importance of the 

portion. The viability of the remainder 

of the range, should the three 

populations in Nebraska be lost, will 

remain high: All of the highly and 

moderately resilient populations occur 

in the remainder of the range, which is 

comprised of more than 20 populations 

distributed through a geographically 

connected area, and which contains all 

of the ecological settings this species is 

known to inhabit. 

Additionally, to determine 

significance of this threatened portion of 

the range, we examined its contribution 

to the species’ viability in terms of its 

resiliency, redundancy, and 

representation. Regarding redundancy, 

the populations within this portion of 

the range occur on the eastern extreme 

of the historical range of the species and 

represent a very small component of the 

total distribution of the species, 

occurring downstream of several highly 

viable populations. Therefore, these 

populations do not substantially 

increase redundancy at the species 

level. Regarding resiliency, individual 

plants in this portion of the range may 

be resilient to dewatering or other 

stressors, but populations contain few 

individuals and are, therefore, 

threatened by stochastic events. 

Regarding representation, we 

understand that there may be 

connectivity among the populations 

occurring in Nebraska and the 

populations upstream on Lodgepole 

Creek in Wyoming. However, this 

connectivity is likely only through 

limited pollinator movement among the 

few flowering plants at any location, 

and through seed dispersal downstream 

from Wyoming to Nebraska, considering 

the distance is too great (>1 km/0.6 mi) 

for most pollinators to travel (Heidel 

2016, pers. comm.). Consequently, the 

populations in Nebraska are likely not 

contributing any genetic information 

upstream. We do not have genetic 

information on these populations, but 

we understand that the populations in 

this portion of the species’ range do not 

occupy unique ecological settings, have 

unique morphology, or have differing 

phenology than other populations of the 

species on Lodgepole Creek or in the 

rest of the species’ range. 

After careful examination of the 

Colorado butterfly plant population in 

the context of our definition of 

‘‘significant portion of its range,’’ we 

determine an area on the periphery of 

the range warranted further 

consideration because threats are 

geographically concentrated there. After 

identifying this area, we evaluate 

whether it is significant and determine 

that it is not significant because, even 

without Colorado butterfly plants in this 

area, the species would not be in danger 

of extinction, or likely to become so in 

the foreseeable future. This is because 

the remainder of the species is 

characterized by high levels of 

resiliency, redundancy, and 

representation; the remainder of the 

species contains all of the highly and 

moderately resilient populations (high 

resiliency), is comprised of more than 

20 populations distributed through a 

geographically connected area (high 

redundancy), and includes all of the 

ecological settings this species is known 

to inhabit (high representation). 

Therefore, we did not need to determine 

if the species is in danger of extinction 

or likely to become so in the foreseeable 

future in this peripheral area in 

Nebraska. 

Determination of Status for the 

Colorado Butterfly Plant 

We have carefully assessed the best 

scientific and commercial information 

available regarding the past, present, 

and future threats to the Colorado 

butterfly plant. The threats that led to 

the species being listed under the Act 

(primarily loss of the species’ habitat 

(Factor A) and small population size, 

restricted range, and herbicide spraying 

(Factor E)) have not occurred to the 

extent anticipated at the time of listing, 

or are being appropriately managed by 

the actions of multiple conservation 

partners over the past 18 years. These 

actions include habitat management, 


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monitoring, and research. Given 

commitments shown by private 

landowners, local governments, 

cooperating agencies, and other partners 

as discussed under Factor D, we expect 

conservation efforts will continue to 

support a healthy, viable population of 

the species post-delisting and into the 

foreseeable future. Furthermore, there is 

no information to conclude that at any 

time over the next 20 years (as we 

define the foreseeable future for this 

species) the species will be in danger of 

extinction. Because the species is not in 

danger of extinction now or within the 

foreseeable future throughout all or any 

significant portion of its range, the 

species does not meet the definition of 

an endangered species or threatened 

species. We therefore propose to remove 

the Colorado butterfly plant from the 

Federal List of Endangered and 

Threatened Wildlife at 50 CFR 17.11(h) 

due to recovery. Because the species is 

neither in danger of extinction now nor 

likely to become so in the foreseeable 

future throughout all or any significant 

portion of its range, the species does not 

meet the definition of an endangered 

species or a threatened species under 

the Act. 

Effects of the Rule 

This proposal, if made final, would 

revise 50 CFR 17.12(h) to remove the 

Colorado butterfly plant from the 

Federal List of Endangered and 

Threatened Plants. The prohibitions and 

conservation measures provided by the 

Act, particularly through sections 7 and 

9, would no longer apply to this species. 

Federal agencies would no longer be 

required to consult with the Service 

under section 7 of the Act in the event 

that activities they authorize, fund, or 

carry out may affect the Colorado 

butterfly plant or its designated critical 

habitat. This proposal, if made final, 

would also remove the designation of 

critical habitat for the Colorado butterfly 

plant in Wyoming (codified at 50 CFR 

17.96(a)). 

Post-Delisting Monitoring 

Section 4(g)(1) of the Act requires us, 

in cooperation with the States, to 

implement a monitoring program for not 

less than 5 years for all species that have 

been delisted due to recovery. The 

purpose of this requirement is to 

develop a program that detects the 

failure of any delisted species to sustain 

itself without the protective measures 

provided by the Act. If, at any time 

during the monitoring period, data 

indicate that protective status under the 

Act should be reinstated, we can initiate 

listing procedures, including, if 

appropriate, emergency listing. 

We are proposing delisting for the 

Colorado butterfly plant based on 

recovery actions taken and new 

information we have received. Since 

delisting would be due in part to 

recovery actions taken by Warren AFB, 

Fort Collins, and BLM, we have 

prepared a draft post-delisting 

monitoring plan for the Colorado 

butterfly plant. The plan has been 

developed with input from these and 

other partners. 

It is our intent to work with our 

partners towards maintaining the 

recovered status of the Colorado 

butterfly plant. While not required, we 

intend to seek peer review comments on 

the draft post-delisting monitoring plan 

(PDM plan), including its objectives and 

procedures. A copy of the draft PDM 

plan is available at http://

www.regulations.gov under Docket No. 

FWS–R6–ES–2018–0008. You can 

submit your comments on the draft 

PDM plan by one of the methods listed 

above under ADDRESSES. 

Required Determinations 

Clarity of This Proposed Rule 

We are required by Executive Orders 

12866 and 12988 and by the 

Presidential Memorandum of June 1, 

1998, to write all rules in plain 

language. This means that each rule we 

publish must: 

(a) Be logically organized; 

(b) Use the active voice to address 

readers directly; 

(c) Use clear language rather than 

jargon; 

(d) Be divided into short sections and 

sentences; and 

(e) Use lists and tables wherever 

possible. 

If you feel that we have not met these 

requirements, send us comments by one 

of the methods listed in ADDRESSES. To 

better help us revise the rule, your 

comments should be as specific as 

possible. For example, you should tell 

us the numbers of the sections or 

paragraphs that are unclearly written, 

which sections or sentences are too 

long, the sections where you feel lists or 

tables would be useful, etc. 

National Environmental Policy Act 

We have determined that 

environmental assessments and 

environmental impact statements, as 

defined under the authority of the 

National Environmental Policy Act of 

1969 (42 U.S.C. 4321 et seq.), need not 

be prepared in connection with 

regulations pursuant to section 4(a) of 

the Act. We published a notice outlining 

our reasons for this determination in the 

Federal Register on October 25, 1983 

(48 FR 49244). 

Government-to-Government 

Relationship With Tribes 

In accordance with the President’s 

memorandum of April 29, 1994, 

Government-to-Government Relations 

with Native American Tribal 

Governments (59 FR 22951), E.O. 13175, 

and the Department of the Interior’s 

manual at 512 DM 2, we readily 

acknowledge our responsibility to 

communicate meaningfully with 

recognized Federal Tribes on a 

government-to-government basis. In 

accordance with Secretarial Order 3206 

of June 5, 1997 (American Indian Tribal 

Rights, Federal-Tribal Trust 

Responsibilities, and the Endangered 

Species Act), we readily acknowledge 

our responsibilities to work directly 

with Tribes in developing programs for 

healthy ecosystems, to acknowledge that 

tribal lands are not subject to the same 

controls as Federal public lands, to 

remain sensitive to Indian culture, and 

to make information available to Tribes. 

We have determined that no Tribes will 

be affected by this rule. 

References Cited 

A complete list of all references cited 

in this proposed rule is available at 

http://www.regulations.gov at Docket 

No. FWS–R6–ES–2018–0008, or upon 

request from the Wyoming Ecological 

Services Field Office (see ADDRESSES). 

Authors 

The primary authors of this proposed 

rule are staff members of the Wyoming 

Ecological Services Field Office. 

List of Subjects in 50 CFR Part 17 

Endangered and threatened species, 

Exports, Imports, Reporting and 

recordkeeping requirements, 

Transportation. 

Proposed Regulation Promulgation 

Accordingly, we hereby propose to 

amend part 17, subchapter B of chapter 

I, title 50 of the Code of Federal 

Regulations, as set forth below: 

PART 17—ENDANGERED AND 

THREATENED WILDLIFE AND PLANTS 

■ 1. The authority citation for part 17 

continues to read as follows: 

Authority: 16 U.S.C. 1361–1407; 1531– 

1544; and 4201–4245, unless otherwise 

noted. 

§ 17.12 [Amended] 

■ 2. Amend § 17.12(h) by removing the 

entry ‘‘Gaura neomexicana ssp. 

coloradensis’’ under ‘‘FLOWERING 

PLANTS’’ from the List of Endangered 

and Threatened Plants. 


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26640 Federal Register / Vol. 83, No. 111 / Friday, June 8, 2018 / Proposed Rules 

§ 17.96 [Amended] 

■ 3. Amend § 17.96(a) by removing the 

entry ‘‘Family Onagraceae: Gaura 

neomexicana ssp. coloradensis 

(Colorado butterfly plant)’’. 

Dated: May 15, 2018. 

James W. Kurth, 

Deputy Director, U.S. Fish and Wildlife 

Service, Exercising the Authority of the 

Director, for the U.S. Fish and Wildlife 

Service. 

[FR Doc. 2018–12409 Filed 6–7–18; 8:45 am] 

BILLING CODE 4333–15–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

50 CFR Part 660 

RIN 0648–XE456 

Pacific Fisheries Management Council; 

Notice of Intent To Withdraw an 

Environmental Impact Statement for 

Gear Rule Changes for the Pacific 

Coast Groundfish Fishery Trawl Catch 

Share Program 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Withdrawal of notice of intent 

to prepare an environmental impact 

statement. 

SUMMARY: NMFS is issuing this notice to 

advise Federal, state, and local 

government agencies and the public that 

it is withdrawing its Notice of Intent 

(NOI) to prepare a draft Environmental 

Impact Statement (EIS) for the proposed 

action to revise regulations regarding 

the use and configuration of groundfish 

bottom trawl and midwater trawl gear in 

the Pacific Coast Groundfish Fishery’s 

Trawl Catch Share Program, also called 

the Trawl Rationalization Program. 

After completion of the analysis, NMFS 

determined the impacts associated with 

this action would not reach a level 

necessitating an EIS, and is instead 

preparing an Environmental Assessment 

(EA). 

DATES: The environmental impact 

statement for the proposed regulations 

is withdrawn as of June 8, 2018. 

FOR FURTHER INFORMATION CONTACT: 

Colin Sayre, NMFS West Coast Regional 

Office, telephone: (206) 526–4656, or 

email: colin.sayre@noaa.gov. 

SUPPLEMENTARY INFORMATION: NMFS 

Published a NOI in the Federal Register 

on March 3, 2016 (81 FR 11189) to 

prepare an EIS in accordance with the 

National Environmental Policy Act 

(NEPA) to analyze the impacts on the 

human environment resulting from 

changes to gear requirements for 

groundfish bottom trawl and midwater 

trawl gear in the Trawl Rationalization 

Program. Additional details about the 

range of alternatives considered in this 

action are included in the March 3, 

2016, NOI, and are not repeated here. 

NMFS solicited public input on the 

scope of the analysis through a public 

comment on the NOI from March 3, 

2016, to April 4, 2016. 

Upon completion of the analysis for 

the proposed action, NMFS determined 

that the impacts associated with the 

implementation of the proposed action 

would not be significant and, therefore, 

there is no need to complete the EIS. 

Instead, NMFS is completing an EA, in 

compliance with NEPA, for the 

proposed action. Therefore, NMFS is 

withdrawing the NOI to prepare an EIS. 

NMFS plans to circulate the draft EA for 

public review and comment concurrent 

with publication of the proposed rule 

for this action. 

Authority: 16 U.S.C. 1801 et seq. 40 CFR 

1500–1508; and Companion Manual for 

NOAA Administrative Order 216–6A, 82 FR 

4306 

Dated: June 1, 2018. 

Jennifer M. Wallace, 

Acting Director, Office of Sustainable 

Fisheries, National Marine Fisheries Service. 

[FR Doc. 2018–12165 Filed 6–7–18; 8:45 am] 

BILLING CODE 3510–22–P 


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