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63625Federal Register / Vol. 78, No. 206/ Thursday, October 24, 2013 / Proposed Rules

SpeciesHistoric range

Vertebrate popu-lation where endan-gered or threatened

Status When listedCriticalhabitat

Specialrules

Common name Scientific name

* * * * * * *Skipperling,

Poweshiek.Oarisma poweshiek U.S.A. (IL, IA, IN,

MI, MN, WI, ND,SD); Canada(Manitoba).

NA ........................... E .................... NA NA

* * * * * * *

3. Amend 17.47 by adding paragraph(b) to read as follows:

17.47 Special rulesinsects.

* * * * *(b) Dakota skipper (Hesperia dacotae).(1) Which populations of the Dakota

skipper are covered by this special rule?This rule covers the distribution ofDakota skipper in the United States.

(2) Prohibitions. Except as noted inparagraph (b)(3) of this section, all

prohibitions and provisions of 17.31and 17.32 apply to the Dakota skipper.

(3) Exemptions from prohibitions.Incidental take of Dakota skipper willnot be a violation of section 9 of the Actif it occurs as a result of:

(i) Recreational trail maintenanceactivities;

(ii) Mowing of section line rights ofway; and

(iii) Routine livestock ranchingactivities that are conducted inaccordance with applicable State,Federal, tribal, and local laws andregulations. For the purposes of this

rule, routine livestock ranchingactivities include:(A) Fence construction and

maintenance.(B) Activities pertaining to livestock

gathering and management, such as theinstallation and maintenance of corrals,loading chutes, and other livestockworking facilities.

(C) Development and maintenance oflivestock watering facilities.

(D) Spot-spraying of herbicides fornoxious weed control (Broadcastapplication of herbicides is notallowed.).

(E) Haying, as set forth in thisparagraph (b)(3)(i)(E):

(1) In native haylands, which aretypically cut in August after theneedlegrass (Hesperostipa spp. orNassella viridula) awns drop, hayingafter July 15 is allowed.

(2) In replanted grasslands (grasslandsreplanted on formerly plowed orcultivated lands) or in tame haylands(grasslands comprising primarilynonnative grass species, such as smooth

brome (Bromus inermis inermis)),mowing may occur at any time.

(F) Grazing of cattle, bison, or horses,except in Kittson County, Minnesota,and Eddy, McHenry, Richland, Rolette,Sargent, and Stutsman Counties, NorthDakota, where the Dakota skipperinhabits areas that may be especiallysensitive to the effects of grazing bythese types of livestock.

* * * * *

Dated: September 23, 2013.

Rowan W. Gould,

Acting Director, U.S. Fish and WildlifeService.

[FR Doc. 201324175 Filed 102313; 8:45 am]

BILLING CODE 431055P

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWSR3ES20130017; 4500030113]

RIN 1018AZ58

Endangered and Threatened Wildlife

and Plants; Designation of CriticalHabitat for Dakota Skipper andPoweshiek Skipperling

AGENCY: Fish and Wildlife Service,Interior.

ACTION: Proposed rule.

SUMMARY: We, the U.S. Fish andWildlife Service, propose to designatecritical habitat for the Dakota skipperand Poweshiek skipperling under theEndangered Species Act of 1973, asamended. The Endangered Species Actrequires that critical habitat bedesignated to the maximum extentprudent and determinable for speciesdetermined to be endangered orthreatened species. The effect of thisregulation is to designate critical habitatfor the Dakota skipper and Poweshiekskipperling under the EndangeredSpecies Act.

DATES: Written Comments: We willaccept comments received orpostmarked on or before December 23,2013. Comments submittedelectronically using the FederaleRulemaking Portal (see ADDRESSES

section, below) must be received by11:59 p.m. Eastern Time on the closingdate. We must receive requests forpublic hearings, in writing, at theaddress shown in ADDRESSESbyDecember 9, 2013.

Public Informational Meetings: Tobetter inform the public of theimplications of the proposed listing andto answer any questions regarding thisproposed rule, we plan to hold fivepublic informational meetings. We have

scheduled informational meetingsregarding the proposed rule in thefollowing locations:

(1) Minot, North Dakota, on November5, 2013, at the Souris Valley Suites, 80037th Avenue SW;

(2) Milbank, South Dakota, onNovember 6, 2013, at the MilbankChamber of Commerce, 1001 East 4thAvenue;

(3) Milford, Iowa, on November 7,2013, at the Iowa Lakeside Laboratory,1838 Highway 86;

(4) Holly, Michigan, on November 13,2013, at the Rose Pioneer ElementarySchool, 7110 Milford Road; and

(5) Berlin, Wisconsin, on November14, 2013, at the Berlin Public Library,121 West Park Avenue.

Except for the meeting in Berlin,Wisconsin, each informational meetingwill be from 5:30 p.m. to 8:00 p.m.; themeeting in Berlin, Wisconsin will befrom 4:30 p.m. to 7:00 p.m.ADDRESSES: You may submit comments

by one of the following methods:(1) Electronically: Go to the Federal

eRulemaking Portal: http://www.regulations.gov. In the Search box,enter FWSR3ES20130017, which isthe docket number for this rulemaking.

You may submit a comment by clickingon Comment Now! If your commentswill fit in the provided comment box,please use this feature of http://www.regulations.gov, as it is mostcompatible with our comment reviewprocedures. If you attach yourcomments as a separate document, ourpreferred file format is Microsoft Word.If you attach multiple comments (suchas form letters), our preferred format isa spreadsheet in Microsoft Excel.

(2) By hard copy: Submit by U.S. mailor hand-delivery to: Public Comments

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63626 Federal Register / Vol. 78, No. 206/ Thursday, October 24, 2013 / Proposed Rules

Processing, Attn: FWSR3ES20130017; Division of Policy and DirectivesManagement; U.S. Fish and WildlifeService; 4401 N. Fairfax Drive, MS2042PDM; Arlington, VA 22203.

We request that you send commentsonly by the methods described above.We will post all comments on http://www.regulations.gov. This generally

means that we will post any personalinformation you provide us (see thePublic Comments section below formore information).

The coordinates or plot points or bothfrom which the maps are generated areincluded in the administrative recordfor this critical habitat designation andare available at (http://www.fws.gov/midwest/Endangered/),www.regulations.gov at Docket No.FWSR3ES20130017, and at theTwin Cities Ecological Services Office(see FOR FURTHER INFORMATION CONTACT).Any additional tools or supporting

information that we may develop forthis critical habitat designation will alsobe available at the Fish and WildlifeService Web site and Field Office set outabove, and may also be included athttp://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:Peter Fasbender, Field Supervisor, U.S.Fish and Wildlife Service, Twin CitiesEcological Services Office, 4101American Boulevard East, Bloomington,Minnesota 55425, by telephone 6127253548 or by facsimile 6127253609. Persons who use atelecommunications device for the deaf

(TDD) may call the Federal InformationRelay Service (FIRS) at 8008778339.

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule. Underthe Endangered Species Act (Act), anyspecies that is determined to be athreatened or endangered speciesrequires critical habitat to be designated,to the maximum extent prudent anddeterminable. Designations andrevisions of critical habitat can only becompleted by issuing a rule. Elsewherein todays Federal Register, we propose

to list the Dakota skipper (Hesperiadacotae) and Poweshiek skipperling(Oarisma poweshiek) as endangeredspecies under the Act.

This rule proposes to designatecritical habitat for Dakota skipper andPoweshiek skipperling.

We are proposing critical habitat forDakota skipper and Poweshiekskipperling under the Act.

Approximately 11,243 hectares (ha)(27,782 acres (ac)) are being proposedfor designation as critical habitat for theDakota skipper in Chippewa, Clay,

Kittison, Lincoln, Murray, Norman,Pipestone, Polk, Pope, and SwiftCounties in Minnesota; McHenry,McKenzie, Ransom, Richland, Rolette,and Wells Counties in North Dakota;and Brookings, Day, Deuel, Grant,Marshall, and Roberts Counties in SouthDakota. Approximately 10,596 ha(26,184 ac) are being proposed for

designation as critical habitat for thePoweshiek skipperling, in Cerro Gordo,Dickinson, Emmet, Howard, Kossuth,and Osceola Counties in Iowa; inHilsdale, Jackson, Lenawee, Livingston,Oakland, and Washtenaw Counties inMichigan; Chippewa, Clay, Cottonwood,Douglas, La Qui Parle, Lincoln, Lyon,Mahnomen, Murray, Norman,Pipestone, Pope, Swift, and WilkinCounties in Minnesota; Ransom,Richland, and Sargent Counties in NorthDakota; Brookings, Day, Deuel, Grant,Marshall, Moody, and Roberts Countiesin South Dakota; and Green Lake and

Waukesha Counties in Wisconsin. Intotal, approximately 15,797 ha (39,035ac) is being proposed as critical habitatfor both species combined, asapproximately 6,042 ha (14,931 ac) ofproposed critical habitat is common to

both species.The basis for our action. Under the

Endangered Species Act, any speciesthat is determined to be a threatened orendangered species shall, to themaximum extent prudent anddeterminable, have habitat designatedthat is considered to be critical habitat.Section 4(b)(2) of the Endangered

Species Act states that the Secretaryshall designate and make revisions tocritical habitat on the basis of the bestavailable scientific data after taking intoconsideration the economic impact,national security impact, and any otherrelevant impact of specifying anyparticular area as critical habitat. TheSecretary may exclude an area fromcritical habitat if she determines that the

benefits of such exclusion outweigh thebenefits of specifying such area as partof the critical habitat, unless shedetermines, based on the best scientificdata available, that the failure todesignate such area as critical habitatwill result in the extinction of thespecies.

We are preparing an economicanalysis of the proposed designations ofcritical habitat. In order to considereconomic impacts, we are preparing ananalysis of the economic impacts of theproposed critical habitat designationsand related factors. We will announcethe availability of the draft economicanalysis as soon as it is completed, atwhich time we will seek additionalpublic review and comment.

We will seek peer review. We areseeking comments from independentspecialists to ensure that our criticalhabitat proposal is based onscientifically sound data and analyses.We have invited these peer reviewers tocomment on our specific assumptionsand conclusions in this critical habitatproposal. Because we will consider all

comments and information we receiveduring the comment period, our finaldeterminations may differ from thisproposal.

Information Requested

We intend that any final actionresulting from this proposed rule will be

based on the best scientific andcommercial data available and be asaccurate and as effective as possible.Therefore, we request comments orinformation from other concernedgovernment agencies, the scientificcommunity, industry, or any other

interested party concerning thisproposed rule. We particularly seekcomments concerning:

(1) The reasons we should or shouldnot designate habitat as criticalhabitat under section 4 of the Act (16U.S.C. 1531 et seq.), including whetherthere are threats to the species fromhuman activity, the degree of which can

be expected to increase due to thedesignation, and whether that increasein threat outweighs the benefit ofdesignation such that the designation ofcritical habitat may not be prudent.

(2) Specific information on:

(a) The amount and distribution ofDakota skipper and Poweshiekskipperling habitat;

(b) What areas, that were occupied atthe time of listing (or are currentlyoccupied) and that contain featuresessential to the conservation of thespecies, should be included in thedesignation and why;

(c) Special managementconsiderations or protection that may beneeded in critical habitat areas we areproposing, including how to implementlivestock grazing, haying, or prescribedfire in a manner that is conducive to theconservation of Dakota skipper orPoweshiek skipperling, and managingfor the potential effects of climatechange; and

(d) What areas not occupied at thetime of listing are essential for theconservation of the species and why.

(3) Land use designations and currentor planned activities in the subject areasand their possible impacts on proposedcritical habitat.

(4) Information on the projected andreasonably likely impacts of climatechange on the Dakota skipper and



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Poweshiek skipperling and proposedcritical habitat.

(5) Any probable economic, nationalsecurity, or other relevant impacts ofdesignating any area that may beincluded in the final designation; inparticular, any impacts on small entitiesor families, and the benefits of includingor excluding areas that exhibit these

impacts.(6) Whether any specific areas we are

proposing for critical habitatdesignation should be considered forexclusion under section 4(b)(2) of theAct, and whether the benefits ofpotentially excluding any specific areaoutweigh the benefits of including thatarea under section 4(b)(2) of the Act. Forinstance, should the final designationexclude properties that are underconservation easement to the U.S. Fishand Wildlife Service or anotherconservation agency, or properties held

by conservation organizations, andwhy? In addition, we are seekinginformation to better understand howthe exclusion or inclusion of specificprivate lands in the final critical habitatdesignation would affect privatelandowner interest and acceptance ofprograms that are intended to conservenative grasslands in the range of Dakotaskipper and Poweshiek skipperling. Weseek any information relevant topotential exclusion of any proposedcritical habitat unit, and particularlyseek information relating toconservation programs or plans of anykind that may protect butterfly habitaton these units. Exclusion of any number

of proposed critical habitat units,pursuant to section 4(b)(2) of the Act iswithin the range of possible decisions inthe final rule.

(7) Whether any specific Tribally-owned areas we are proposing forcritical habitat designation should beconsidered for exclusion from finaldesignation under section 4(b)(2) of theAct, and information regarding themanagement of those areas.

(8) Whether we could improve ormodify our approach to designatingcritical habitat in any way to provide forgreater public participation and

understanding, or to betteraccommodate public concerns andcomments.

Please include sufficient informationwith your submission (such as scientificjournal articles or other publications) toallow us to verify any scientific orcommercial information you include.

Please note that submissions merelystating support for or opposition to theaction under consideration withoutproviding supporting information,although noted, will not be consideredin making a determination, as section

4(b)(1)(A) of the Act directs that listingand critical habitat determinations must

be made solely on the basis of the bestscientific and commercial dataavailable.

You may submit your comments andmaterials concerning this proposed rule

by one of the methods listed inADDRESSES. We request that you send

comments only by the methodsdescribed in the ADDRESSES section.

If you submit information via http://www.regulations.gov, your entiresubmissionincluding any personalidentifying informationwill be postedon the Web site. If your submission ismade via a hardcopy that includespersonal identifying information, youmay request at the top of your documentthat we withhold this information frompublic review. However, we cannotguarantee that we will be able to do so.We will post all hardcopy submissionson http://www.regulations.gov. Please

include sufficient information with yourcomments to allow us to verify anyscientific or commercial informationyou include.

Comments and materials we receive,as well as supporting documentation weused in preparing this proposed rule,will be available for public inspectionon http://www.regulations.gov, or byappointment, during normal businesshours, at the U.S. Fish and WildlifeService, Twin Cities Ecological ServicesOffice (see FOR FURTHER INFORMATIONCONTACT).

Previous Federal Actions

All previous Federal actions aredescribed in the proposal to list theDakota skipper as a threatened speciesand the Poweshiek skipperling as anendangered species under theEndangered Species Act publishedelsewhere in todays Federal Register.

Critical Habitat

Background

For more information on Dakotaskipper and Poweshiek skipperlingtaxonomy, life history, habitat, andpopulation descriptions and our

proposal to list the species under theAct, please refer to the proposed rule tolist the species that is publishedelsewhere in todays Federal Register.

It is our intent to discuss below onlythose topics directly relevant to thedesignation of critical habitat for theDakota skipper and Poweshiekskipperling in this section of theproposed rule.

Critical habitat is defined in section 3of the Act as:

(1) The specific areas within thegeographical area occupied by the

species, at the time it is listed inaccordance with the Act, on which arefound those physical or biologicalfeatures

(a) Essential to the conservation of thespecies and

(b) Which may require specialmanagement considerations orprotection; and

(2) Specific areas outside thegeographical area occupied by thespecies at the time it is listed, upon adetermination that such areas areessential for the conservation of thespecies.

Conservation, as defined undersection 3 of the Act, means to use andthe use of all methods and proceduresthat are necessary to bring anendangered or threatened species to thepoint at which the measures providedpursuant to the Act are no longernecessary. Such methods andprocedures include, but are not limitedto, all activities associated withscientific resources management such asresearch, census, law enforcement,habitat acquisition and maintenance,propagation, live trapping, andtransplantation, and, in theextraordinary case where populationpressures within a given ecosystemcannot be otherwise relieved, mayinclude regulated taking.

Critical habitat receives protectionunder section 7 of the Act through therequirement that Federal agenciesensure, in consultation with the Service,that any action they authorize, fund, orcarry out is not likely to result in the

destruction or adverse modification ofcritical habitat. The designation ofcritical habitat does not affect landownership or establish a refuge,wilderness, reserve, preserve, or otherconservation area. Such designationdoes not allow the government or publicto access private lands. Suchdesignation does not requireimplementation of restoration, recovery,or enhancement measures by non-Federal landowners. Where a landownerrequests Federal agency funding orauthorization for an action that mayaffect a listed species or critical habitat,

the consultation requirements of section7(a)(2) of the Act would apply, but evenin the event of a destruction or adversemodification finding, the obligation ofthe Federal action agency and thelandowner is not to restore or recoverthe species, but to implementreasonable and prudent alternatives toavoid destruction or adversemodification of critical habitat.

Under the first prong of the Actsdefinition of critical habitat, areaswithin the geographical area occupied

by the species at the time it was listed



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are included in a critical habitatdesignation if they contain physical or

biological features (1) essential to theconservation of the species and (2)which may require special managementconsiderations or protection. For theseareas, critical habitat designationsidentify, to the extent known using the

best scientific and commercial data

available, those physical or biologicalfeatures that are essential to theconservation of the species (such asspace, food, cover, and protectedhabitat). In identifying those physical or

biological features within an area, wefocus on the principal biological orphysical constituent elements (primaryconstituent elements such as roost sites,nesting grounds, seasonal wetlands,water quality, tide, soil type) that areessential to the conservation of thespecies. Primary constituent elementsare the elements of physical or

biological features that provide for a

species life-history processes, and areessential to the conservation of thespecies.

Under the second prong of the Actsdefinition of critical habitat, we candesignate critical habitat in areasoutside the geographical area occupied

by the species at the time it is listed,upon a determination that such areasare essential for the conservation of thespecies. For example, an area that wasrecently occupied, but not occupied atthe time of listing, may be essential tothe conservation of the species and may

be included in the critical habitat

designation. We designate criticalhabitat in areas outside the geographicalarea occupied by a species only when adesignation limited to its range would

be inadequate to ensure theconservation of the species.

Section 4 of the Act requires that wedesignate critical habitat on the basis ofthe best scientific data available.Further, our Policy on InformationStandards Under the EndangeredSpecies Act (published in the FederalRegister on July 1, 1994 (59 FR 34271)),the Information Quality Act (section 515of the Treasury and General

Government Appropriations Act forFiscal Year 2001 (Pub. L. 106554; H.R.5658)), and our associated InformationQuality Guidelines, provide criteria,establish procedures, and provideguidance to ensure that our decisionsare based on the best scientific dataavailable. They require our biologists, tothe extent consistent with the Act andwith the use of the best scientific dataavailable, to use primary and originalsources of information as the basis forrecommendations to designate criticalhabitat.

When we are determining which areasshould be designated as critical habitat,our primary source of information isgenerally the information developedduring the listing process for thespecies. Additional information sourcesmay include the recovery plan for thespecies, articles in peer-reviewedjournals, conservation plans developed

by States and counties, scientific statussurveys and studies, biologicalassessments, other unpublishedmaterials, or experts opinions orpersonal knowledge.

Habitat is dynamic, and species maymove from one area to another overtime. Climate change will be a particularchallenge for biodiversity because theinteraction of additional stressorsassociated with climate change andcurrent stressors may push species

beyond their ability to survive (Lovejoy2005, pp. 325326). The synergisticimplications of climate change and

habitat fragmentation are the mostthreatening facet of climate change forbiodiversity (Hannah and Lovejoy 2005,p. 4). Current climate changepredictions for terrestrial areas in theNorthern Hemisphere indicate warmerair temperatures, more intenseprecipitation events, and increasedsummer continental drying (Field et al.1999, pp. 13; Hayhoe et al. 2004, p.12422; Cayan et al. 2005, p. 6;Intergovernmental Panel on ClimateChange (IPCC) 2007, p. 1181). Climatechange may lead to increased frequencyand duration of severe storms anddroughts (Golladay et al. 2004, p. 504;

McLaughlin et al. 2002, p. 6074; Cooket al. 2004, p. 1015).

We recognize that critical habitatdesignated at a particular point in timemay not include all of the habitat areasthat we may later determine arenecessary for the recovery of thespecies. For these reasons, a criticalhabitat designation does not signal thathabitat outside the designated area isunimportant or may not be needed forrecovery of the species. Areas that areimportant to the conservation of thespecies, both inside and outside thecritical habitat designation, will

continue to be subject to: (1)Conservation actions implementedunder section 7(a)(1) of the Act, (2)regulatory protections afforded by therequirement in section 7(a)(2) of the Actfor Federal agencies to ensure theiractions are not likely to jeopardize thecontinued existence of any endangeredor threatened species, and (3) theprohibitions of section 9 of the Act ifactions occurring in these areas maytake the species. Federally funded orpermitted projects affecting listedspecies outside their designated critical

habitat areas may still result in jeopardyfindings in some cases. Theseprotections and conservation tools willcontinue to contribute to recovery ofthis species. Similarly, critical habitatdesignations made on the basis of the

best available information at the time ofdesignation will not control thedirection and substance of future

recovery plans, habitat conservationplans (HCPs), or other speciesconservation planning efforts if newinformation available at the time ofthese planning efforts calls for adifferent outcome.

Prudency Determination

Section 4(a)(3) of the Act, asamended, and implementing regulations(50 CFR 424.12), require that, to themaximum extent prudent anddeterminable, the Secretary shalldesignate critical habitat at the time thespecies is determined to be anendangered or threatened species. Ourregulations (50 CFR 424.12(a)(1)) statethat the designation of critical habitat isnot prudent when one or both of thefollowing situations exist:

(1) The species is threatened by takingor other human activity, andidentification of critical habitat can beexpected to increase the degree of threatto the species, or

(2) such designation of critical habitatwould not be beneficial to the species.

There is currently no immediatethreat of take attributed to collection orvandalism (see the Summary of FactorsAffecting the Species section of the

proposed listing rule publishedelsewhere in todays Federal Register)for either the Dakota skipper orPoweshiek skipperling, andidentification and mapping of criticalhabitat is not expected to initiate anysuch threat. In the absence of findingthat the designation of critical habitatwould increase threats to a species, ifthere are any benefits to a criticalhabitat designation, then a prudentfinding is warranted. Here, the potential

benefits of designation include: (1)Triggering consultation under section 7of the Act, in new areas for actions inwhich there may be a Federal nexuswhere it would not otherwise occur

because, for example, it is or hasbecome unoccupied or the occupancy isin question; (2) focusing conservationactivities on the most essential featuresand areas; (3) providing educational

benefits to State or county governmentsor private entities; and (4) preventingpeople from causing inadvertent harmto the species. Therefore, because wehave determined that the designation ofcritical habitat will not likely increasethe degree of threat to the Dakota



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skipper or Poweshiek skipperling andmay provide some measure of benefit,we find that designation of criticalhabitat is prudent for the Dakota skipperand Poweshiek skipperling.

Critical Habitat Determinability

Having determined that designation isprudent, under section 4(a)(3) of the Act

we must find whether critical habitat forthe Dakota skipper and Poweshiekskipperling is determinable. Ourregulations at 50 CFR 424.12(a)(2) statethat critical habitat is not determinablewhen one or both of the followingsituations exist:

(i) Information sufficient to performrequired analyses of the impacts of thedesignation is lacking, or

(ii) The biological needs of the speciesare not sufficiently well known topermit identification of an area ascritical habitat.

When critical habitat is notdeterminable, the Act allows the Service

an additional year to publish a criticalhabitat designation (16 U.S.C.1533(b)(6)(C)(ii)).

We reviewed the availableinformation pertaining to the biologicalneeds of the species and habitatcharacteristics where these species arelocated. This and other informationrepresent the best scientific dataavailable and led us to conclude that thedesignation of critical habitat isdeterminable for the Dakota skipper andPoweshiek skipperling.

Physical or Biological Features

In accordance with section 3(5)(A)(i)and regulations at 50 CFR 424.12(b), indetermining which areas within thegeographical area occupied by thespecies at the time of listing to designateas critical habitat, we consider thephysical or biological features that areessential to the conservation of thespecies and which may require specialmanagement considerations orprotection. These include, but are notlimited to:

(1) Space for individual andpopulation growth and for normal

behavior;(2) Food, water, air, light, minerals, or

other nutritional or physiologicalrequirements;

(3) Cover or shelter;(4) Sites for breeding, reproduction, or

rearing (or development) of offspring;and

(5) Habitats that are protected fromdisturbance or are representative of thehistorical geographic and ecologicaldistributions of a species.

Dakota Skipper

We derived the specific physical orbiological features required for the

Dakota skipper from studies of thespecies habitat, ecology, and life historyas described below. Additionalinformation can be found in theBackground section of the proposedlisting rule, published elsewhere intodays Federal Register. We havedetermined that the following physicalor biological features are essential for

the Dakota skipper:Space for Individual and PopulationGrowth and for Normal Behavior

Dakota skippers are obligate residentsof remnant (untilled) high-qualityprairiehabitats that are dominated bynative grasses and that contain a highdiversity of native forbs (floweringherbaceous plants). Dakota skipperhabitat has been categorized into twomain types: Type A habitat is describedas high-quality, low (wet-mesic) prairiewith little topographic relief that occurson near-shore glacial lake deposits,dominated by little bluestem grass(Schizachyrium scoparium), with thelikely presence of wood lily (Lilium

philadelphicum), bluebell bellflower(Campanula rotundifolia), andmountain deathcamas (smooth camas;Zigadenus elegans) (McCabe 1981, p.190; Royer and Marrone 1992a, pp. 8,1416, 21). Type B habitat is describedas rolling native-prairie terrain overgravelly glacial moraine deposits and isdominated by bluestems and needle-grasses (e.g., Hesperostipa spartea) withthe likely presence of bluebell

bellflower, wood lily, purple coneflower(Echinacea angustifolia), upright prairie

coneflower (Ratibida columnifera), andcommon gaillardia (Gaillardia aristata)(Royer and Marrone 1992a, pp. 2122).

Dry prairies are described to have asparse shrub layer (less than 5 percentcover) composed mainly of leadplant(Amorpha canescens), with prairie rose(Rosa arkansana) and wormwood sage(Artemisia frigida) often present(Minnesota Department of NaturalResources 2012a, p. 1). Taller shrubs,such as smooth sumac (Rhus glabra),may also be present. Occasional trees,such as bur oak (Quercus macrocarpa)or black oak (Quercus velutina), may

also be present but remain less thanapproximately 5 percent cover(Minnesota Department of NaturalResources 2012a, p. 1). Similarly, wet-mesic prairies are described to have asparse shrub layer (less than 5 to 25percent cover) of leadplant, prairie rose,wolfberry (Symphoricarposoccidentalis), and other native shrubssuch as gray dogwood (Cornusracemosa), American hazelnut (Corylusamericana), and wild plum (Prunusamericana) (Minnesota Department ofNatural Resources 2012b, p. 1).

Therefore, based on the informationabove, we identify high-quality Type Aor Type B native remnant (untilled)prairie, as described above, containing amosaic of native grasses and floweringforbs and sparse shrub and tree cover to

be a physical or biological featureessential to the conservation of theDakota skipper.

Nonnative invasive plant species,such as Kentucky bluegrass (Poa

pratensis) and smooth brome (Bromusinermus) may outcompete native plantsthat are necessary for the survival ofDakota skipper and lead to thedeterioration or elimination of nativevegetation. Dakota skipper depend on adiversity of native plants endemic totallgrass and mixed-grass prairies;therefore, when nonnative or woodyplant species become dominant, Dakotaskipper populations decline due toinsufficient sources of larval food andnectar for adults. Therefore, native

prairies, as described above, with anabsence or only sparse presence ofnonnative invasive plant species is aphysical or biological feature essentialto the conservation of the Dakotaskipper.

Royer and Marrone (1992a, p. 25)concluded that Dakota skippers are notinclined to dispersal, although theydid not describe individual ranges ordispersal distances. Concentratedactivity areas for Dakota skippers shiftannually in response to local nectarsources and disturbance (McCabe 1979,p. 9; 1981, p. 186). Marked adultsmoved across less than 200 meters (m)

(656 feet (ft)) of unsuitable habitatbetween two prairie patches and movedalong ridges more frequently than acrossvalleys (Dana 1991, pp. 3738). Averagemovements of recaptured adults wereless than 300 m (984 ft) over 37 days.Dana (1997, p. 6) later observed reducedmovement rates across a small valleywith roads and crop fields comparedwith movements in adjacent widespreadprairie habitat.

Dakota skipper are not known todisperse widely and have low mobility;experts estimate Dakota skipper has amean mobility of 3.5 (standard

deviation = 0.71) on a scale of 0(sedentary) to 10 (highly mobile) (Burkeet al. 2011, Fitzsimmons 2012, pers.comm.). Five Dakota skipper expertsinterviewed in 2001 indicated that itwas unlikely that Dakota skippers werecapable of moving greater than 1kilometer (km) (0.6 miles (mi)) betweenpatches of prairie habitat separated bystructurally similar habitats (e.g.,perennial grassland, but not necessarilynative prairie) (Cochrane and Delphey2002, p. 6). The species will not likelydisperse across unsuitable habitat, such



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as certain types of row crops (e.g., corn,beets), or anywhere not dominated bygrasses. Skadsen (1999, p. 2) reportedpossible movement of unmarked Dakotaskippers from a known population atleast 800 m (2,625 ft) away to a site withan unusually heavy growth of purpleconeflower where he had not foundDakota skippers in three previous years

when coneflower production wassparse. The two sites were connected bynative vegetation of varying qualitywith a few asphalt and gravel roadsinterspersed (Skadsen in litt. 2001).

Dakota skipper may move in responseto local nectar sources, disturbance, orin search of a mate. The tallgrass prairiethat once made up a vast ecosystemprior to European settlement has now

been reduced to fragmented remnantsthat make up less than 1 to 15 percentof the original land area across thespecies range (Samson and Knopf 1994,p. 419). Similarly, mixed-grass prairie

has been reduced to fragmentedremnants that make up less than 1, 19,and 28 percent of the original land areain Manitoba, Saskatchewan, and NorthDakota, respectively (Samson and Knopf1994, p. 419). Before the range-widefragmentation of prairie habitat, thespecies could move freely acrosssuitable tallgrass and mixed-grassprairie and between high-qualityprairies through suitable dispersalhabitat. Now, these fragmentedpopulations need immigration corridorsfor dispersal from nearby populations toprevent genetic drift and perhaps toreestablish a population after local

extirpation. Therefore, based on theinformation above, we identifyundeveloped dispersal habitat,structurally similar to suitable high-quality prairie habitat, as describedabove, to be a physical or biologicalfeature essential to the conservation ofthe Dakota skipper. These dispersalhabitats should be adjacent to or

between high-quality prairie patchesand within the known dispersaldistance of Dakota skipper; within 1 km(0.6 mi) from suitable high-quality TypeA or Type B prairie and should havelimited shrub and tree cover, and no or

limited amounts of certain row crops,which may act as barriers to dispersal.In summary, we identify high-quality

wet-mesic or dry (Type A and Type B)remnant (untilled) prairie containing amosaic of native grasses and floweringforbs to be a physical or biologicalfeature necessary to allow for normal

behavior and population growth ofDakota skipper. Both wet-mesic and dryprairies have limited tree and low shrubcoverage that may act as barriers todispersal and limited or no invasiveplant species that may lead to a change

in the plant community. Dispersalhabitat, structurally similar to suitablehigh quality prairie habitat and adjacentto or between high-quality prairiepatches should be located within theknown dispersal distance of Dakotaskipper (within 1 km (0.6 miles) fromsuitable high-quality Type A or Type Bprairie) to help maintain genetic

diversity and to provide refuges fromdisturbance.

Food, Water, Air, Light, Minerals, orOther Nutritional or PhysiologicalRequirements

Dakota skipper larvae feed only on afew native grass species; little bluestemis a frequent food source (Dana 1991, p.17; Royer & Marrone 1992a, p. 25),although they have also been found onPanicwn spp., Poa spp., and othernative grasses (Royer and Marrone1992a, p. 25). Seasonal senescencepatterns (timing of growth) of grassspecies relative to the larval period ofDakota skippers are likely important indetermining the suitability of grassspecies as larval host plants becausewarm-season grasses such as little

bluestem grow and stay green andpalatable from June through earlySeptember, the months when Dakotaskipper larvae are feeding (NRCS 2004,p. 1). By contrast, cool-season grassessuch as the nonnative Kentucky

bluegrass grow during the cooler springand fall (NRCS 2004, p. 1), and are,therefore, not available during the larvalperiod of Dakota skipper. Consequently,

based on the information above, we

identify native grass species, such aslittle bluestem, to be a physical or

biological feature essential to theconservation of the Dakota skipper.These native grasses should be availableduring the larval stage of Dakotaskipper.

Adult Dakota skippers may useseveral species of native forbs as nectarsources, which can vary regionally.Examples of adult nectar sourcesinclude: Purple coneflower, bluebell

bellflower, white prairie clover (Daleacandida), upright prairie coneflower,fleabanes (Erigeron spp.), blanketflowers

(Gaillardia spp.), black-eyed Susan,yellow sundrops (Calylophusserrulatus), groundplum milkvetch(Astragalus crassicarpus), deathcamas(smooth camas), common primrose, andtooth-leaved primrose (Calylophusserrulata) (McCabe and Post 1977b, p.36, McCabe 1979, p. 42, 1981, p. 187,Royer and Marrone 1992a, p. 21,Swengel and Swengel 1999, pp. 280281). Plant species likely vary in theirvalue as nectar sources for Dakotaskipper due to the amount of nectaravailable to the species during the adult

flight period (Dana 1991, p. 48).Swengel and Swengel (1999, pp. 280281) observed nectaring at 25 plantspecies, but 85 percent of theobservations were at the following threetaxa, in declining order of frequency:Purple coneflower, blanketflower, andgroundplum milkvetch. Dana (1991, p.21) reported the use of 25 nectar species

in Minnesota with purple coneflowermost frequented. Flowering forbs alsoprovide water necessary to avoiddesiccation (drying out) during theflight period (Dana 2013, pers. comm.).Therefore, based on the informationabove, we identify the availability ofnative nectar plant species, including

but not limited to, those listed above tobe a physical or biological feature forthis species. These nectar plant speciesshould be flowering during the Dakotaskippers adult flight period.

Dakota skipper larvae are vulnerableto desiccation during hot, dry weather,

and this vulnerability may increase inthe western parts of the species range(Royer et al. 2008, p. 15). Compaction ofsoils in the mesic and relatively flatType A habitats may alter vertical waterdistribution and lead to decreasedrelative humidity levels near the soilsurface (Gardiner and Miller 2007, pp.3640, 510511; Frede 1985 in Royer2008, p. 2), which would furtherincrease the risk of desiccation (Royer2008, p. 2). Soils associated with dryand wet-mesic prairies are described ashaving a seasonally high water table andmoderate to high permeability. Soil

textures in Dakota skipper habitats areclassified as loam, sandy loam, or loamysand (Royer and Marrone 1992b, p. 15,Skadsen 1997, Lenz 1999, pp. 45, 8,Swengel and Swengel 1999, p. 282);soils in moraine deposits are describedas gravelly, but the deposits associatedwith glacial lakes are not described asgravelly. The native-prairie grasses andflowering forbs detailed in the abovesections are typically found on thesesoil types (Lenz 1999, pp. 45, 8), andplant species diversity is generallyhigher in remnant prairies where thesoils have never been plowed (Higginset al. 2000, pp. 2324). Cultivationchanges the physical state of the soil,including changes to bulk density(compaction), which may hinder seedgermination and root growth (Tomkoand Hall 1986, pp. 173175; Miller andGardiner 2007, pp. 510511).Furthermore, certain native prairieplants are found only in prairies thatlack a tillage history (Higgins et al. 2000,p. 23). Finally, bulk density affects plantgrowth (Gardiner and Miller 2008, p. 36)and, therefore, can alter the plantcommunity. For example, Dakota



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skippers appear to be generally absentfrom Type A habitat in North Dakotawhen it is grazed due to a shift awayfrom a plant community that is suitablefor the species (McCabe 1979, p. 17;McCabe 1981, p. 179). The shift in plantcommunity composition may occurrapidly (McCabe 1981, p. 179; Royerand Royer 1998, p. 23).

Therefore, we identify loam, sandyloam, loamy sand, or gravelly soils thathave never been plowed or tilled to bea physical feature essential to theconservation of the Dakota skipper.

In summary, the biological featuresthat provide food sources include nativegrass species for larval food, such aslittle bluestem and prairie dropseed,and native forb plant species for adultnectar sources, such as purpleconeflower, bluebell bellflower, whiteprairie clover, upright prairieconeflower, fleabanes, blanketflowers,

black-eyed Susan, and groundplummilkvetch. These prairies haveundisturbed (untilled) edaphic (relatedto soil) features that are conducive tothe development and survival of larvalDakota skipper and soil textures that areloam, sandy loam, loamy sand, orgravelly.

Cover or Shelter

Dakota skippers oviposit (lay eggs) onbroadleaf plants such as Astragalus spp.(McCabe 1981, p. 180) and grasses suchas little bluestem, big bluestem(Andropogon gerardii), sideoatsgramma, prairie dropseed, porcupinegrass (Hesperostipa spartea), and

Wilcoxs Panic Grass (Dichantheliumwilcoxianum) (Dana 1991, p. 17). Afterhatching, Dakota skipper larvae crawl tothe bases of grasses where they formshelters at or below the ground surfacewith silk fastened together with planttissue (Dana 1991, p. 16). Dakotaskippers overwinter in their ground-level or subsurface shelters duringeither the fourth or fifth instar (Dana1991, p. 15; McCabe 1979, p. 6; 1981;Royer & Marrone 1992a, pp. 2526). Inthe spring, larvae resume feeding andundergo two additional molts beforethey pupate. During the last two instars,

larvae shift from buried shelters tohorizontal shelters at the soil surface(Dana 1991, p. 16). Therefore, sufficientavailability of grasses used to formshelters at or below the ground surfaceis a physical or biological featureessential for cover and shelter forDakota skipper larvae.

As discussed above, Dakota skipperlarvae are vulnerable to desiccation(drying out) during hot, dry weather;this vulnerability may increase in thewestern parts of the species range(Royer et al. 2008, p. 15). Compaction of

soils in the mesic and relatively flatType A habitats may alter vertical waterdistribution and lead to decreasedrelative humidity levels near the soilsurface, Gardiner and Miller 2007, pp.3640, 510511; Frede 1985 in Royer2008, p. 2), which would furtherincrease the risk of desiccation (Royer2008, p. 2). Soils associated with wet-

mesic prairies are described as having aseasonally high water table andmoderate to high permeability (Lenz1999, pp. 45). Cultivation changes thephysical state of soil (Tomko and Hall1986, pp. 173175; Gardiner and Miller2007, pp. 510511), by, for example,changes to bulk density (compaction)that result in slower water movementthrough the soil (e.g., Tomko and Hall1986, pp. 173175). Furthermore,

because Dakota skipper spend a portionof their larval stage underground, thesoil must remain undisturbed (untilled)during that time. Therefore, we identify

untilled glacial soils including, but notlimited to, loam, sandy loam, loamysand, or gravelly soils to be a physicalfeature essential to the conservation ofthe Dakota skipper.

Sites for Breeding, Reproduction, orRearing (or Development) of Offspring

The annual, single generation of adultDakota skippers emerges from mid-Juneto early July, depending on the weather,with flights starting earlier farther westin the range (McCabe 1979, p. 6, 1981,p. 180, Dana 1991, p. 1, Royer andMarrone 1992a, p. 26, Skadsen 1997, p.3, Swengel and Swengel 1999, p. 282).

During this time, adult male Dakotaskippers typically perch on tall grassesand forbs, and occasionally appear topatrol in search of mating opportunities(Royer and Marrone 1992a, p. 25).Therefore, the physical or biologicalfeatures essential to the conservation ofthe Dakota skipper include above-ground parts of grasses and forbs forperching that are available during theadult flight period.

The local flight period lasts two tofour weeks and mating occursthroughout this period (McCabe 1979, p.6, 1981, p. 180, Dana 1991, p. 15).

Adults are thought to disperse amaximum of 1.0 mi (1.6 km) in searchof a mate or nectar sources (Cochraneand Delphey 2002, p. 6). During thistime, adult Dakota skippers depend onnectar plants for food and water.Therefore, it is important that nectarplants are available in close proximityto areas suitable for oviposition andlarval feeding.

Dakota skippers lay eggs on broadleafplants such as Astragalus spp. (McCabe1981, p. 180) and grasses such as little

bluestem, big bluestem (Andropogon

gerardii), sideoats gramma, prairiedropseed, porcupine grass(Hesperostipa spartea), and WilcoxsPanic Grass (Dichantheliumwilcoxianum) (Dana 1991, p. 17),although larvae feed only on nativegrasses, such as little bluestem (Dana1991, p. 17; Royer and Marrone 1992a,p. 25) and prairie dropseed (Royer and

Marrone 1992a, p. 25). After hatching,Dakota skipper larvae crawl to the basesof grasses where they form shelters at or

below the ground surface (Dana 1991, p.16) and emerge at night from theirshelters to forage (McCabe 1979, p. 6,1981, p. 181, Royer and Marrone 1992a,p. 25). Dakota skippers overwinter intheir ground-level or subsurface sheltersduring either the fourth or fifth instar(McCabe 1979, p. 6, 1981, p. 181, Dana1991, p. 15, Royer and Marrone 1992a,pp. 2526). In the spring, larvae resumefeeding and undergo two additionalmolts before they pupate. During the

last two instars, larvae shift from buriedshelters to horizontal shelters at the soilsurface (Dana 1991, p. 16). Therefore,the physical or biological featuresessential to the conservation of theDakota skipper include above- and

below-ground parts of grasses foroviposition and larval shelters andforaging; these grasses should be inclose proximity to nectar plants wherethe adults are feeding during the shortflight period.

Dakota skipper larvae spend most ofthe summer at or near the soil surface(McCabe 1981, p. 181, Dana 1991, p.

15), therefore, biological factors such asavailability of nectar and larval foodsources, edaphic features such as bulkdensity (an indicator of soil compaction)and soil moisture, as well as relatednon-biotic factors such as temperatureand relative humidity at and near (to a2.0 cm depth; 0.79 in) the soil surfacemay limit the survival of the sensitivelarval and pupal stages of Dakotaskippers (Royer et al. 2008, p. 2). Soilevaporation rates in the north-centralUnited States are substantially affected

by microtopography (variations of thesoil surface on a small scale) (Cooper1960 in Royer et al. 2008, p. 2). Forexample, removal of vegetation due toheavy livestock grazing, plowing, fire,and soil compaction alters evaporationand water movement through the soil,thereby altering the humidity of soilnear the surface (e.g., Tomko and Hall1986, pp. 173175; Zhao et al. 2010, pp.9396), although the timing andintensity of these operations may affectthe results. Livestock grazing canincrease soil bulk density (an indicatorof soil compaction) (Greenwood et al.1997, pp. 413, 416418; Gardiner and



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Miller 2007, pp. 510511; Zhao et al.2007, p. 248), particularly when the soilis wet (Gardiner and Miller 2008, p.510), and these increases have beencorrelated with decreased soil watercontent and movement of water throughthe soil (Zhao et al. 2007, p. 248). Theloss of porosity results in higher bulkdensities, thereby decreasing water

movement through the soil (Warren etal. 1986, pp. 493494).

Similarly, vehicle traffic (includingtilling and harvesting) increasescompaction (Gardiner and Miller 2008,pp. 36, 510), and tilled land increases

bulk densities (e.g., Tomko and Hall1986, pp. 173175). During the hot anddry summer months, these changes inthe soil restrict the movement ofshallow groundwater to the soil surface,thus resulting in a dry soil layer duringthe time when Dakota skipper larvae arevulnerable to desiccation (Royer et al.2008, p. 2). Furthermore, bulk density

affects plant growth (Gardiner andMiller 2008, p. 36) and, therefore, canalter the plant community. For example,Dakota skippers appear to be generallyabsent from Type A habitat in NorthDakota when it is grazed due to a shiftaway from a plant community that issuitable for the species (McCabe 1979,p. 17; McCabe 1981, p. 179). The shiftin plant community composition andadverse effects to Dakota skipperpopulations may occur rapidly (McCabe1981, p. 179; Royer and Royer 1998, p.23).

The following are acceptable levelsfor microclimatological (climate in a

small space, such as at or near the soilsurface) variables between the soilsurface and 2.0 cm (0.79 in) deepthroughout the range of Dakota skippersduring the summer season (from wheneggs are laid through when larvae enterdiapause near the end of September);mean temperature range of 17.8 to 20.5C (64.0 to 68.9 F), mean dew pointranging from 13.9 to 16.8 C (57.0 to62.2 F), and mean relative humidity

between 72.5 and 85.1 percent (Royer2008, pp. 7, 1415). Type A habitats, asdiscussed above, are topographically oflow relief (little change in elevation)

(less than l m (3.2 ft)), with sandy soilsthat are relatively free of gravel at leastto depths of 60 cm (23.6 in) and nearlysaturated at depths between 40 and 60cm (15.7 to 23.6 in). In these habitattypes, soil bulk density exceeds 1.0gram/cubic centimeter (g/cm3) (0.8ounce/cubic inch (oz/in3) (Royer et al.2008, p. 14). Type A habitat has a highwater table (0.3 to 1.8 m (1 to 6 ft)) andis subject to intermittent flooding in thespring, but provides some habitat that isnot flooded during the spring larvalgrowth period (Royer et al. 2008, p. 15).

Bulk density at Dakota skipper sites(including Type A and Type B habitats)ranged from approximately 0.9 g/cm3 to1.3 g/cm3 (0.5 oz/in3 to 0.7 oz/in3), bulkdensity in Type A habitat ranged from1.0 g/cm3 to 1.3 g/cm3 (0.6 oz/in3 to 0.7oz/in3), whereas mean bulk densities inType B habitat are below 1.0g/cm3 (0.8oz/in3) (Royer et al. 2008, p. 10). The

gravelly soils of type B habitats areconsiderably more compact at all depthsthan the bulk density of Type A habitat,perhaps due to the presence of graveland its effect on the accuracy of theinstrument (Royer 2008, p. 15). Soiltextures in Dakota skipper Type Ahabitats are classified as loam, sandyloam, or loamy sand (Royer et al. 2008,pp. 35, 1415). Type B habitats areassociated with gravelly glaciallandscapes of predominantly sandyloams and loamy sand soils withrelatively higher relief, more variablesoil moisture, and slightly higher soil

temperatures than Type A habitats(Royer et al. 2008, p. 15).Edaphic features that allow for micro-

climate (between the soil surface and2.0 cm (0.8 in) deep) conditions that areconducive to Dakota skipper larvaesurvival during the summer monthsinclude, specifically, mean summertemperatures from 17.8 to 20.5 C (64.0to 68.9 F), mean dew point rangingfrom 13.9 to 16.8 C (57.0 to 62.2 F),mean relative humidity between 72.5and 85.1 percent, and bulk densities

between 0.86 g/cm3 and 1.28 g/cm3 (0.5oz/in3 to 0.74 oz/in3). Thesemicroclimatological levels are

characteristic of untilled glacial soils.Furthermore, as described above,intensive livestock grazing can increasesoil bulk density (an indicator of soilcompaction)the effects of grazing aredependent on the intensity and timingof grazing and soil type. The increasesin soil bulk density increases have beencorrelated with decreased soil watercontent and movement of water throughthe soil. Therefore, untilled glacial soilsthat are not subject to intensive grazingpressure are physical or biologicalfeatures essential to the conservation ofthe Dakota skipper.

Habitats Protected From Disturbance orRepresentative of the Historical,Geographic, and EcologicalDistributions of the Species

The Dakota skipper has a restrictedgeographic distribution. Species whosepopulations exhibit a high degree ofisolation are extremely susceptible toextinction from both random andnonrandom catastrophic natural orhuman-caused events. Therefore, it isessential to maintain the native tallgrassprairies and native mixed-grass prairies

upon which the Dakota skipperdepends. This means protection fromdestruction or conversion, disturbancecaused by exposure to land managementactions (e.g., intense grazing, firemanagement, early haying, andherbicide or pesticide use), flooding,lack of management, and nonnativespecies that may degrade the availability

of native grasses and flowering forbs.The Dakota skipper must, at aminimum, sustain its currentdistribution for the species to continueto persist. Introduced nonnative speciesare a serious threat to native tallgrassprairies and native mixed-grass prairieson which Dakota skipper depends((Orwig 1997, pp. 4 and 8, Skadsen2002, p. 52, Royer and Royer 2012b, p.1516, 2223); see both Factor C:Disease and Predation, and Factor E:Other Natural or Manmade FactorsAffecting Its Continued Existencesections of our proposed listing rule

published elsewhere in todays FederalRegister). Because the distribution ofthe Dakota skipper is isolated and itshabitat so restricted, introduction ofcertain nonnative species into its habitatcould have significant negativeconsequences. Dakota skipper typicallyoccur at sites embedded in agriculturalor developed landscapes, which makesthem more susceptible to nonnative orwoody plant invasion.

Potentially harmful nonnative speciesinclude leafy spurge (Euphorbia esula),Kentucky bluegrass, alfalfa (Medicagosativa), glossy buckthorn (Frangulaalnus), smooth brome, purple loosestrife

(Lythrum salicaria), Canada thistle(Cirsium arvense), reed canary grass(Phalaris arundinacea), gray dogwood(Cornus racemosa), and others (Orwig1997, pp. 4 and 8, Skadsen 2002, p. 52,Royer and Royer 2012b, pp. 1516, 2223). Once these plants invade a site,they replace or reduce the coverage ofnative forbs and grasses used by adultsand larvae of both butterflies. Leafyspurge displaces native plant speciesand its invasion is facilitated by actionsthat remove native plant cover andexpose mineral soil (Belcher and Wilson1989, p. 172). The threat from nonnative

invasive species is compounded by theencroachment of native woody speciesinto native-prairie habitat. Invasion oftallgrass and mixed-grass prairie bywoody vegetation such as glossy

buckthorn reduces light availability,total plant cover, and the coverage ofgrasses and sedges (Fiedler and Landis2012, pp. 44, 5051). This in turnreduces the availability of both nectarand larval host plants for Dakotaskipper.

Dakota skippers are obligate residentsof undisturbed high-quality prairie,



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ranging from wet-mesic tallgrass prairieto dry-mesic mixed-grass prairie (Royerand Marrone 1992a, pp. 8, 21). High-quality prairie contains a high diversityof native species, including floweringherbaceous species (forbs). Degradedhabitat consists of a high abundance ofnonnative plants, woody vegetation, anda low abundance of native grasses and

flowering forbs available during thelarval growth period and a lowabundance of native flowering forbsavailable during adult nectaring periods.Intensive grazing or fire managementpractices, early haying, flooding, as wellas lack of management create suchdegraded habitats. Conversion toagriculture or other development alsodegrades or destroys native-prairiehabitat. Therefore, based on theinformation above, we identify thenecessary physical or biological featuresfor the Dakota skipper as nondegradednative tallgrass prairie and native

mixed-grass prairie habitat devoid ofnonnative plant species, or habitat inwhich nonnative plant species andnonnative woody vegetation are atlevels that allow persistence of Dakotaskipper.

Poweshiek Skipperling

We derived the specific physical orbiological features required for thePoweshiek skipperling from studies ofthe species habitat, ecology, and lifehistory as described below. Additionalinformation can be found in theBackground section of the proposedlisting rule, published elsewhere in

todays Federal Register. We havedetermined that the following physicalor biological features are essential forthe Poweshiek skipperling:

Space for Individual and PopulationGrowth and for Normal Behavior

The full range of habitat preferencesfor Poweshiek skipperling includeshigh-quality prairie fens, grassy lake andstream margins, remnant moistmeadows, and wet-mesic to dry tallgrassremnant (untilled) prairies. These areasare dominated by native-prairie grasses,such as little bluestem and prairie

dropseed (Sporobolus heterolepis), butalso contain a high diversity of nativeforbs, including black-eyed Susan(Rudbeckia hirta) and palespike lobelia(Lobelia spicata). The disjunctpopulations of Poweshiek skipperling inMichigan occur in prairie fens,specifically, in peat domes within largerprairie fen complexes in areas co-dominated by mat muhly (Muhlenbergiarichardsonis) and prairie dropseed(Cuthrell 2011, pers. comm.).

Dry prairies are described to have asparse shrub layer (less than 5 percent

of cover) composed mainly of leadplant,with prairie rose and wormwood sageoften present (Minnesota Department ofNatural Resources 2012a, p. 1). Tallershrubs, such as smooth sumac, may also

be present. Occasional trees, such as buroak or black oak, may also be present

but remain less than 5 percent cover(Minnesota Department of Natural

Resources 2012a, p. 1). Similarly, wet-mesic prairies are described to have asparse shrub layer (less than 525percent cover) of leadplant, prairie rose,wolfberry, and other native shrubs suchas gray dogwood, American hazelnut,and wild plum (Minnesota Departmentof Natural Resources 2012b, p. 1).

Nonnative invasive plant species,such as Kentucky bluegrass and smooth

brome, may outcompete native plantsthat are necessary for the survival ofPoweshiek skipperling and lead to thedeterioration or elimination of nativevegetation. Poweshiek skipperling

depend on a diversity of native plantsendemic to tallgrass prairies and prairiefens; therefore, when nonnative orwoody plant species become dominant,Poweshiek skipperling populationsdecline due to insufficient sources oflarval food and nectar for adults.Therefore, native prairies as definedabove, with an absence or only sparsepresence of nonnative invasive plantspecies is a physical or biologicalfeature essential to the conservation ofthe Poweshiek skipperling.

The vegetative structure of prairiefens is a result of their unique hydrologyand consists of plants that thrive in

wetlands and calcium-rich soils mixedwith tallgrass prairie and sedge meadowspecies (Michigan Natural FeaturesInventory 2012, p. 1). Three or fourvegetation zones are often present inprairie fens, including diverse sedgemeadows, wooded fen often dominated

by tamarack (Larix laricina), and an areaof calcareous groundwater seepage withsparsely vegetated marl precipitate(clay- or lime-rich soils that formedfrom solids that separated from water) atthe surface (Michigan Natural FeaturesInventory 2012, p. 3). Shrubs and treesthat may be present include shrubby

cinquefoil (Potentilla fruticosa), bogbirch (Betula pumila), and others(Michigan Natural Features Inventory2012, p. 3).

Based on the information above, weidentify high-quality remnant (untilled)wet-mesic to dry tallgrass prairies, moistmeadows, or prairie fen habitat, asdescribed above, containing a highdiversity of native plant species andsparse tree and shrub cover to be aphysical or biological feature essentialto the conservation of the Poweshiekskipperling. These native prairies

should have no or low coverage ofnonnative invasive plant species.

Poweshiek skipperling are not knownto disperse widely. The maximumdispersal distance for male Poweshiekskipperling travelling across contiguoussuitable habitat is estimated to beapproximately 1.6 km (1.0 mi) (Dana2012a, pers. comm.). The species was

evaluated among 291 butterfly speciesin Canada and is thought to haverelatively low mobility, lower mobilitythan that of the Dakota skipper (Burkeet al. 2011; Fitzsimmons 2012, pers.comm.). Therefore, a more conservativeestimated dispersal distance would bethat of the Dakota skipper,approximately 1 km (0.6 mi) (Cochraneand Delphey 2002, p. 6). Poweshiekskipperling frequently perch onvegetation, but males will occasionallypatrol in search of mating opportunities(Royer and Marrone 1992b, p. 15).Poweshiek skipperling may move

between patches of prairie habitatseparated by structurally similarhabitats (e.g., perennial grasslands butnot necessarily native prairie); smallpopulations need immigration corridorsfor dispersal from nearby populations toprevent genetic drift and to reestablisha population after local extirpation. Thespecies will not likely disperse acrossunsuitable habitat, such as certain typesof row crops, or anywhere notdominated by grasses (Westwood 2012,pers. comm.; Dana 2012a, pers. comm.).

Poweshiek skipperling may move inresponse to local nectar sources,disturbance, or in search of a mate. The

tallgrass prairie that once made up avast ecosystem prior to Europeansettlement has now been reduced tofragmented remnants that make up lessthan 1 to 15 percent of the original landarea across the species range (Samsonand Knopf 1994, p. 419). Before therange-wide fragmentation of prairiehabitat, the species could move freelyacross suitable tallgrass prairie and

between high-quality prairies throughsuitable dispersal habitat. Now, thesefragmented populations needimmigration corridors for dispersal fromnearby populations to prevent genetic

drift and perhaps to reestablish apopulation after local extirpation.Therefore, based on the informationabove, we identify undevelopeddispersal habitat, structurally similar tosuitable high-quality prairie habitat, asdescribed above, to be a physical or

biological feature essential to theconservation of the Poweshiekskipperling. These dispersal habitatsshould be adjacent to or between high-quality prairie patches and within theknown dispersal distance of Poweshiekskipperling; within 1 km (0.6 mi) from



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suitable high-quality tallgrass prairie orprairie fen and should have limitedshrub and tree cover, and not consist ofcertain row crops (e.g., corn, beets),which may act as barriers to dispersal.

Food, Water, Air, Light, Minerals, orOther Nutritional or PhysiologicalRequirements

Preferred nectar plants vary across thegeographic range of Poweshiekskipperling. Smooth ox-eye (Heliopsishelianthoides) and purple coneflowerwere noted as the preferred nectarplants in North Dakota, Iowa, andMinnesota (Swengel and Swengel 1999,p. 280, Selby 2005, p. 5). In Wisconsin,other documented nectar speciesinclude stiff tickseed (Coreopsis

palmata), black-eyed Susan, andpalespike lobelia (Borkin 1995b, p. 6).On the relatively wet prairie habitats ofCanada and prairie fens in Michigan,preferred nectar plants are black-eyedSusan, palespike lobelia, sticky tofieldia(Triantha glutinosa), and shrubbycinquefoil (Dasiphora fruticosa ssp.

floribunda) (Bess 1988, p. 13; Catlingand Lafontaine 1986, p. 65; Holzman1972, p. 111; Nielsen 1970, p. 46;Summerville and Clampitt 1999, p.231). Flowering forbs also provide waternecessary to avoid desiccation duringthe flight period (Dana 2013, pers.comm.). Therefore, based on theinformation above, we identify thepresence of native nectar plants, aslisted above, that are flowering duringthe adult flight period of Poweshiekskipperling to be a physical or biological

feature essential to the conservation ofthe Poweshiek skipperling.

Poweshiek skipperling larvae may notrely on a single species of grass for food,

but instead may be able to use a narrowrange of acceptable plant species at asite (Dana 2005, pers. comm.). Dana(2005, pers. comm.) noted that larvaeand ovipositing females prefer grasseswith very fine, threadlike structures.Recent observations indicate that prairiedropseed is the preferred larval foodplant for some Poweshiek skipperlingpopulations (Borkin 1995b, pp. 56);larval feeding has also been observed on

little bluestem (Borkin 1995b, pp. 56)and sideoats grama (Boutelouacurtipendula) (Dana 2005, pers. comm.).Oviposition has been also observed onmat muhly (Cuthrell 2012, pers. comm.),a grass found in Michigans prairie fens(Penskar and Higman 1999, p. 1). Ingeneral, to sustain all larval instars(developmental stages) andmetamorphosis, Poweshiek skipperlingrequire the availability of native, fine-stemmed grasses. Therefore, based onthe information above, we identifynative, fine-stemmed grasses, including

but not limited to prairie dropseed, littlebluestem, sideoats grama, and matmuhly to be a physical or biologicalfeature essential to the conservation ofthe Poweshiek skipperling. These nativegrasses should be available during thelarval stage of Poweshiek skipperling.

Soil textures in areas that overlapwith Poweshiek skipperling sites are

classified as loam, sandy loam, or loamysand (Royer et al. 2008, pp. 3, 10); soilsin moraine deposits are described asgravelly, but the deposits associatedwith glacial lakes are not described asgravelly. Michigan prairie fen habitatsoils are described as saturated organicsoils (sedge peat and wood peat) andmarl, a calcium carbonate (CaCO3)precipitate (Michigan Natural FeaturesInventory Web site accessed August 3,2012). The native-prairie grasses andflowering forbs detailed above aretypically found on these types of soils(Royer et al. 2008, p. 4, Michigan

Natural Features Inventory 2012, pp. 13). As discussed above, plant speciescommunity composition is generallyhigher in remnant prairies where thesoils have never been plowed (Higginset al. 2000, pp. 2324) and certainnative prairie plants are found only inprairies that lack a tillage history(Higgins et al. 2000, p. 23). The physicalstate of cultivated soil can result inslower water movement, which canhamper root growth and seedgermination (e.g., Tomko and Hall 1986,pp. 173175). Therefore, we identifyloam, sandy loam, loamy sand, gravel,organic peat or marl soils that have

never been plowed or tilled to be aphysical feature essential to theconservation of the Poweshiekskipperling.

Cover or Shelter

Poweshiek skipperlings lay their eggsnear native-grasses leaf-blade tips(McAlpine 1972, pp. 8593); McAlpinedid not identify the grasses, but Dana(2005, pers. comm.) noted that larvaeand ovipositing females prefer grasseswith very fine, threadlike structuressuch as prairie dropseed (Borkin 1995b,pp. 56); little bluestem (Borkin 1995b,

pp. 56), sideoats grama (Boutelouacurtipendula) (Dana 2005, pers. comm.),and mat muhly (Cuthrell 2012, pers.comm.). After hatching, Poweshieklarvae crawl to the base of nativegrasses. Larvae emerge at night to forage,clip off blades of grass, and then crawl

back to consume the grass (Dana 2012b,pers. comm.). Unlike Dakota skippers,Poweshiek skipperling do not burrowinto the soil surface (McAlpine 1972,pp. 8892, Borkin 1995b, p. 9).Therefore, sufficient availability ofgrasses used to form shelters at the

ground surface is a physical orbiological feature essential for cover andshelter for Poweshiek skipperlinglarvae.

Similar to Dakota skipper, asdiscussed above, Poweshiek skipperlinglarvae are vulnerable to desiccationduring hot, dry weather and may requirewet low areas to provide relief from

high summer temperatures or fire(Borkin 1994, p. 8, 1995a, p. 10).Poweshiek skipperling adults alsorequire low wet areas to provide refugiafrom fire (Borkin 1994, p. 8, 1995a, p.10). Therefore, based on the informationabove, we identify the presence of lowwet areas that provide shelter and relieffrom high summer temperatures and firefor both larvae and adults, to be aphysical or biological feature for thePoweshiek skipperling.

Sites for Breeding, Reproduction, orRearing (or Development) of Offspring

The annual, single generation of adultPoweshiek skipperling emerges frommid-June to early July, although theactual flight period varies somewhatacross the species range and can alsovary significantly from year-to-yeardepending on weather patterns (Royerand Marrone 1992b, p. 15, Skadsen1997, Swengel and Swengel 1999, p.282). The flight period in a locality laststwo to four weeks, and mating occursthroughout this period (McCabe andPost 1977a, p. 38, Swengel and Swengel1999, p. 282). During this time, adultPoweshiek skipperling depend on

nectar plants for food and water.Therefore, it is important that nectarplants are available in close proximityto areas suitable for oviposition andlarval feeding. Adult male Poweshiekskipperling perch on tall grasses andforbs, and appear to patrol in search ofmating opportunities (Royer andMarrone 1992b, p. 15). Therefore, thephysical or biological features essentialto the conservation of Poweshiekskipperling include above-ground partsof grasses and forbs for perching.

As described above, Poweshiekskipperling lay their eggs near the tips

of leaf blades (McAlpine 1972, pp. 8593). Poweshiek skipperling larvae crawlto the base of grasses and emerge atnight to forage, clip off blades of grass,and then crawl back down to consumethe grass (Dana 2012b, pers. comm.).Therefore, the physical or biologicalfeatures essential to the conservation ofPoweshiek skipperling include above-ground parts of grasses for ovipositionand larval foraging and shelter; thesegrasses should be in close proximity tonectar plants, where the adults arefeeding during the short flight period.



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Poweshiek skipperling larvae arevulnerable to desiccation during hot,dry weather (Borkin 1994, p. 8, 1995a,p. 10). After hatching, Poweshiek larvaecrawl to the base of grasses, but unlikeDakota skippers, Poweshiek skipperlingdo not form shelters underground,therefore, nonbiotic factors such astemperature and relative humidity at

and near (to a 2.0 cm depth; 0.79 in) thesoil surface may limit the survival of thesensitive larval and pupal stages ofPoweshiek skipperling, as has beensuggested for Dakota skippers (Royer etal. 2008, p. 2). Soil evaporation rates inthe north-central United States aresubstantially affected bymicrotopography (evenness of the soilsurface on a small scale) (Cooper 1960in Royer et al. 2008, p. 2). For example,removal of vegetation due to livestockgrazing, plowing, fire, and soilcompaction alters evaporation andwater movement through the soil,

thereby altering the humidity of soilnear the surface (e.g., Tomko and Hall1986, pp. 173175; Zhao et al. 2010, pp.9396). Livestock grazing increases soil

bulk density (an indicator of soilcompaction) (Greenwood et al. 1997,p.l Zhao et al. 2007, p. 248), and theseincreases have been correlated withdecreased soil water content andmovement of water through the soil(Zhao et al. 2007, p. 248). The loss ofporosity results in higher bulk densities,thereby decreasing water movementthrough the soil (Warren et al. 1986, pp.493494). Furthermore, bulk density

affects plant growth (Gardiner andMiller 2008, p. 36) and, therefore, canalter the plant community. For example,a rapid shift in plant community wasdocumented in wet-mesic habitats inNorth Dakota that were grazed (McCabe1979, p. 17, 1981, p. 179). The shift inplant community due to intensivegrazing composition may occur rapidly(McCabe 1981, p. 179; Royer and Royer1998, p. 23). Similarly, tilled landincreases bulk densities (e.g., Tomkoand Hall 1986, pp. 173175). During thehot and dry summer months, thesechanges in the soil restrict themovement of shallow groundwater tothe soil surface (Royer et al. 2008, p. 2),thus resulting in a dry soil layer duringthe summer months (Royer et al. 2008,p. 2), when Poweshiek skipperlinglarvae are vulnerable to desiccation(Borkin 1994, p. 8; Borkin 1995a, p. 10).

Although Poweshiek skipperlinghabitats have not been studiedextensively in terms of micro-climate,Royer (2008, pp. 45) studied six sitesthroughout the range of Dakota skipperthat overlap with Poweshiek skipperlingsites. The six sites represent Type B

habitats, which are described as rollingnative prairie terrain over gravellyglacial moraine deposits (Royer andMarrone 1992a, pp. 2122). Royer (2008,pp. 7, 1415) found the followingacceptable levels formicroclimatological (climate in a smallspace, such as at or near the soil surface)variables between the soil surface and

2.0 cm (0.79 in) deep throughout therange of Dakota skippers during thesummer season (from when eggs are laidthrough when larvae enter diapausenear the end of September): meantemperature range of 17.8 to 20.5 C(64.0 to 68.9 F), mean dew pointranging from 13.9 to 16.8 C (57.0 to62.2 F), and mean relative humidity

between 72.5 and 85.1 percent. Bulkdensity at the six sites ranged from0.86g/cm3 to 0.96 g/cm3 (0.5 oz/in3; to0.55 oz/in3); mean bulk density wasbelow 1.0 g/cm3 (0.8 oz/in3). Type Bhabitat are associated with gravelly

glacial landscapes of predominantlysandy loams and loamy sand soils withrelatively higher relief, more variablesoil moisture, and slightly higher soiltemperatures than Type A habitats(Royer et al. 2008, p. 15). Thesevariables have not been studied in Iowa,Michigan, and Wisconsin sites.

Micro-climate conditions near the soilsurface conducive to Poweshiekskipperling larvae survival arecharacteristic of untilled glacial soilswithout intense grazing pressure.Therefore, untilled glacial soils that arenot subject to intense grazing pressureare physical or biological features

essential to the conservation of thePoweshiek skipperling.

Habitats Protected From Disturbance orRepresentative of the Historical,Geographic, and EcologicalDistributions of the Species

The Poweshiek skipperling has arestricted geographic distribution.Species whose populations exhibit ahigh degree of isolation are extremelysusceptible to extinction from bothrandom and nonrandom catastrophicnatural or human-caused events.Therefore, it is essential to maintain the

native tallgrass prairies and prairie fensupon which the Poweshiek skipperlingdepends. This means protection fromdisturbance caused by exposure to landmanagement actions (cattle grazing, firemanagement, destruction or conversion,early haying, and herbicide or pesticideuse), flooding, water withdrawal ordepletion, water contamination, lack ofmanagement, and nonnative species thatmay degrade the availability of nativegrasses and flowering forbs. ThePoweshiek skipperling must, at aminimum, sustain its current

distribution for the species to continueto persist. Introduced nonnative speciesare a serious threat to native tallgrassprairies and prairie fens on whichPoweshiek skipperling depends ((Orwig1997, pp. 4, 8, MNFI unpubl. data 2011,Skadsen 2002, p. 52, Royer and Royer2012b, pp. 1516, 2223); see bothFactor C: Disease and Predation, and

Factor E: Other Natural or ManmadeFactors Affecting Its ContinuedExistence sections of our proposedlisting rule published elsewhere intodays Federal Register).

Because the distribution of thePoweshiek skipperling is isolated andits habitat so restricted, introduction ofcertain nonnative species into its habitatcould be devastating. Poweshiekskipperling typically occur at sitesembedded in agricultural or developedlandscapes, which makes them moresusceptible to nonnative or woody plantinvasion. Potentially harmful nonnative

species include leafy spurge (Euphorbiaesula), Kentucky bluegrass, alfalfa(Medicago sativa), glossy buckthorn(Frangula alnus), smooth brome, purpleloosestrife (Lythrum salicaria), Canadathistle (Cirsium arvense), reed canarygrass (Phalaris arundinacea), graydogwood (Cornus racemosa), and others(Orwig 1997, p. 4, 8, MNFI unpubl. data2011, Skadsen 2002, p. 52, Royer andRoyer 2012b, pp. 1516, 2223). Oncethese plants invade a site, they replaceor reduce the coverage of native forbsand grasses used by adults and larvae of

both butterflies. Leafy spurge displacesnative plant species and its invasion is

facilitated by actions that remove nativeplant cover and expose mineral soil(Belcher and Wilson 1989, p. 172). Thethreat from nonnative invasive speciesis compounded by the encroachment ofnative woody species into native prairiehabitat. Invasion of tallgrass prairie bywoody vegetation such as glossy

buckthorn reduces light availability,total plant cover, and the coverage ofgrasses and sedges (Fiedler and Landis2012, pp. 44, 5051). This in turnreduces the availability of both nectarand larval host plants for Poweshiekskipperling.

In Michigan, Poweshiek skipperlinglive on prairie fens, which occur on thelower slopes of glacial moraines or icecontact ridges (Albert 1995 in MichiganNatural Features Inventory 2012, p. 1)where coarse glacial deposits providehigh hydraulic connectivity that forcesgroundwater to the surface (Moran 1981in Michigan Natural Features Inventory2012, p. 1). Small lakes, headwaterstreams, or rivers are often associatedwith prairie fens. The sapric peat(partially decomposed vegetation withless than one-third recognizable plant



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sources during the Dakota skipper flightperiod: Purple coneflower (Echinaceaangustifolia), bluebell bellflower(Campanula rotundifolia), white prairieclover (Dalea candida), upright prairieconeflower (Ratibida columnifera),fleabane (Erigeron spp.), blanketflower(Gaillardia spp.), black-eyed Susan(Rudbeckia hirta), yellow sundrops

(Calylophus serrulatus), groundplummilkvetch (Astragalus crassicarpus),common gaillardia (Gaillardia aristata),or tooth-leaved primrose (Calylophusserrulata).

(3) Primary Constituent Element 3Dispersal grassland habitat that iswithin 1 km (0.6 mi) of native high-quality remnant prairie (as defined inPrimary Constituent Element 1) thatconnects high-quality wet-mesic to drytallgrass prairies or moist meadowhabitats. Dispersal grassland habitatconsists of undeveloped open areasdominated by perennial grassland with

limited or no barriers to dispersalincluding tree or shrub cover less than25 percent of the area and no row cropssuch as corn, beans, potatoes, orsunflowers.

With this proposed designation ofcritical habitat, we intend to identify thephysical or biological features essentialto the conservation of the species,through the identification of thefeatures primary constituent elementssufficient to support the life-historyprocesses of the species.

All units and subunits proposed to bedesignated as critical habitat that arecurrently occupied by the Dakota

skipper contain the primary constituentelements sufficient to support the life-history needs of the species. Additionalunoccupied units that we determine areessential for the conservation of thespecies also contain the primaryconstituent elements sufficient tosupport the life-history needs of thespecies.

Poweshiek Skipperling

Under the Act and its implementingregulations, we are required to identifythe physical or biological featuresessential to the conservation of

Poweshiek skipperling in areasoccupied at the time of listing, focusingon the features primary constituentelements. We consider primaryconstituent elements to be the elementsof physical or biological features thatprovide for a species life-historyprocesses and are essential to theconservation of the species.

Based on our current knowledge ofthe physical or biological features andhabitat characteristics required tosustain the species life-historyprocesses, we determine that the

primary constituent elements specific tothe Poweshiek skipperling are:

(1) Primary Constituent Element 1Wet-mesic to dry tallgrass remnantuntilled prairies or remnant moistmeadows containing:

a. A predominance of native grassesand native flowering forbs;

b. Undisturbed (untilled) glacial soil

types including, but not limited to,loam, sandy loam, loamy sand, gravel,organic soils (peat), or marl that providethe edaphic features conducive toPoweshiek skipperling larval survivaland native prairie vegetation;

c. Depressional wetlands or low wetareas, within or adjacent to prairies thatprovide shelter from high summertemperatures and fire;

d. If present, trees or large shrub coverless than 5 percent of area in dryprairies and less than 25 percent in wet-mesic prairies and prairie fens; and

e. If present, nonnative invasive plant

species occurring in less than 5 percentof area.(2) Primary Constituent Element 2

Prairie fen habitats containing:a. A predominance of native grasses

and native flowering forbs;b. Undisturbed (untilled) glacial soil

types including, but not limited to,organic soils (peat), or marl that providethe edaphic features conducive toPoweshiek skipperling larval survivaland native prairie vegetation;

c. Depressional wetlands or low wetareas, within or adjacent to prairies thatprovide shelter from high summertemperatures and fire;

d. Hydraulic features necessary tomaintain prairie fen groundwater flowand prairie fen plant communities;

e. If present, trees or large shrub coverless than 25 percent of the unit; and

f. If present, nonnative invasive plantspecies occurring in less than 5 percentof area.

(3) Primary Constituent Element 3Native grasses and native floweringforbs for larval and adult food andshelter, specifically;

a. At least one of the following nativegrasses available to provide larval foodand shelter sources during Poweshiek

skipperling larval stages: prairiedropseed (Sporobolus heterolepis), littlebluestem (Schizachyrium scoparium),sideoats grama (Boutelouacurtipendula), or mat muhly(Muhlenbergia richardsonis); and

b. At least one of the following forbsin bloom to provide nectar and watersources during the Poweshiekskipperling flight period: purpleconeflower (Echinacea angustifolia),

black-eyed Susan (Rudbeckia hirta),smooth ox-eye (Heliopsishelianthoides), stiff tickseed (Coreopsis

palmata), palespike lobelia (Lobeliaspicata), sticky tofieldia (Trianthaglutinosa), or shrubby cinquefoil(Dasiphora fruticosa ssp. floribunda).

(4) Primary Constituent Element 4Dispersal grassland habitat that iswithin 1 km (0.6 mi) of native high-quality remnant prairie (as defined inPrimary Constituent Element 1) that

connects high quality wet-mesic to drytallgrass prairies, moist meadows, orprairie fen habitats. Dispersal grasslandhabitat consists of the followingphysical characteristics appropriate forsupporting Poweshiek skipperlingdispersal: undeveloped open areasdominated by perennial grassland withlimited or no barriers to dispersalincluding tree or shrub cover less than25 percent of the area and no row cropssuch as corn, beans, potatoes, orsunflowers.

With this proposed designation ofcritical habitat, we intend to identify thephysical or biological features essentialto the conservation of the species,through the identification of thefeatures primary constituent elementssufficient to support the life-historyprocesses of the species. Many of theunits proposed to be designated ascritical habitat are currently occupied

by the Poweshiek skipperling andcontain the primary constituentelements sufficient to support the life-history needs of the species. Additionalunoccupied units also contain theprimary constituent elements sufficientto support the life-history needs of thespecies.

Special Management Considerations orProtection

When designating critical habitat, weassess whether the specific areas withinthe geographical area occupied by thespecies at the time of listing containfeatures that are essential to theconservation

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