8144

• UCREFRP Catalog Number: 8144
• Author: Valdez, R. A.
• Title: Evaluation of Habitat Utilization Curves for Endangered Colorado River Fishes.
• USFW Year: 1985.
• USFW - Doc Type: \
• Copyright Material: NO

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2-1

2.0 hABITAT UTILI2ATIO~ CURVES

2.1 Th~ Concept

The concept or habitat utiliZction curves WnS originated in 1975 by the
1nstrear; Flo\tJ Service Group (IFG) of the wt.:stern Energy and Lan(j Use Te?J'1,
an affiliate of the HIS in Ft.. Col1ir:ls, Colorado. Stalnaker and .A.rnette
(l97b) first alluded to the concept in ttl~ir treatise of instream flow
methoaolcgies. The IFG has proctuced (l seric:s of instrE'erl flo'~ information
papers cescribing tre: concept end its llse in tIle Instrecm Fie\! Incremental
(.:ethodology (IFH'). The development ot habitat U1:i1izc:tion curves is best
described by Bovee (l~)7t.), ('no Bovep and Cochncwer (l~'77).

M(lbitnt uti1izGt;on curVf'S arc cHI inte9rC'l pen: of 'l:t~~ IFI;I. They are
an i~port(Jnt component in (1etl~rn:inin~ the total (mount of (lv~ilable
pr(\iry"rr:'1'J raMit.ot for (l sP;::cies, unCff diff{rpnt ryc'rclllic conditions. Tr.f':
m,=,(~c(1 is cor;posEd of four cornponf:l1ts 1.8ovEf' 2nd Cccnr,aUf't' 1~i7):

1. simulation of the strea~,
2. (1('terrlinat.ion of the distrihution cf ccmbiniltioflS of deot.hs,
velocities, su~st?tes, ~no covrr , by arrr,
"'. d p t co r I" i n ~ t ; 0 n of 3 C 0 ~ p 0 siT. ':. P I" 0 b a tJ il i t Y of u s,_ (f r 0 ~ r. a bit (> t
lltilizrli";or. cur':,:s) fOI" ':'''lCri cor;bil'1C'ticr: of h~hilCt. r?r;,rrt'O'rs found
~Ji i:hi n tlH? strf'r'l1T' re?c h, an(!
lJ.. t!":r-- c:'!lr.uli":t:ion of a \'/eiclltc::r~ uS2bl~ are,l (rouc:hly r. hnhitc:t's C.:'lrryins
("'-'p.~cHy bdsed on rhysiccl c.:cncitinns alof1~) far ('-~ch spf.cics enrj lit?
f'1i s'r:.ory pbase: unl:ler i r1'if.' sri 0ati on, i'.'t vi"r; OUS st.rer1.f'1 ci sch;-rt"Tf's.

L .::: i :O!'1('nc 1(1 tl! re

ji'F COPc'.rt r.i:S un(:~rocm' scv.c~r'dl s"'r:ps in rHir',pnclc't:ur;:l evolution
lnr.'ludin~ tl,F '-err.'s: rrehrcncf curvc:s, .1E-C+iv;ry Cl;rv~s, protC'biliT.Y
criterid or proh(\bility-of-us(' criter1ii (Bovee 15:h; LoveE: Anc1 Cochnauer
1':-'77), hcoitat suitability curvE'S (Pr0v,.;tt (t <:1. l~Ll), suitahility-of-use
crit€riiJ, pr('fcr~;nc(' f(Jctors, scl()ctivity t2.r.tcrs (;'r1'1rlur pt ('1. l%j), anc
habitnt utillzaticn curv("s. f:?ny ot HIE'S€' t.":'rr:.s arc still in use: to
cescrib€ the concept or ij portion thf'rr:of. The curren'" nomenclature: is
"ni:bitat utilization i.urves", as describcri hy a hebitat pJram~t~r on the
X-Rxis ftnd a "suitability inrl~x" on the V-axis.

2.: ASSt!rp1:icns

H~bit~t utilization curves ar~ b~sprl 0r the assu~ption that in~ivi~uals
of a SPPc1CS t~n(, to select '(he Most fcH'c,rebl(- conritions c,vailc:ble for
~:.:,Ditation ..:ithin i'l strri"'r1 (i'.i1hous ('t ..1. lS'iili). !n(livirluJls \/ill utilizp
trf' ("Irea ~"ittl less freotJency ?!S candi1.10nS r.~.'C()fl'(' less fJvorabh ClPr: ~.lill
eventually lp~ve an ~rfa before ccnrli~iors beccne lethal. lherefore,
in(!lVit1l1t'lls shot/le be mo:t frenucntly chsrfV(.rt c'r sC1r.1!,,1~.(i inhJbitin9 \Jreas
'f/ith their most prpferrr'd hcbit?t cOnclitions.

It is mplicltly ;jSSUl'lHl T:nat th: frt'CH'~'nc:y ot obs...rvin~ d sf'l""ciFs in i'!
piJl~ticulilr h0bitdt is il'1oici.tivc of l1abiT?t su1tr;bi/ity. It;s (11 so (lSSU!TIf'Q