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<br />".( <br />.::"\.. <br /> <br />",I q,. 'TD <br />~_ t.... <br /> <br />8:}? <br /> <br />L. <br /> <br />r. Uf <br /> <br />I; 13: <br /> <br />ROLE OF !oIA'I1Jl{f,{. DISTURBANCE <br /> <br />Flo.yJiog Is t.t.e r.l0~t. CO"lnon tldt.ur'al foril! of rjlstu:-bo.nce In t.he riparian zone. <br />It ..:-an be d';.hE::r' ~Bst:,u('tive Or' const...uctive to t.he plant community. Tne <br />C:o:gl'ee of dlsturtance 1s dep<;;,odent. all flood ff'eql..:ency, duration, and intensity. <br /> <br />De~osition of o:ganic and mineral material is important t~ the recruitment and <br />surlJival of rlpar1a:1 specIes (Gecy and Wilson 1990). Major floods Dove and <br />relocate debris and vegetatioJ:"'i within t.te rlp3ria:'l zone. SOl'le plants are <br />rel:!o'Jed anrl others have t.heir root systems scoured allow~ng for regeneration <br />thro:.lgh root sprouting (Swro 1991). In a natural ecosystem t.he vegetation and <br />flous tend to be in dynar.:lc equllibrium. The plants present in a reach are a <br />fun~tion of the full spectru~ cf stre3~flows. <br /> <br />Many r!parbn sp~ci~~s, including, cottonwood a'1rj willow, require floeding for <br />rege~eratjGn. Tr.es~ spec:es germin3te un w~t 50il and require several ueeks of <br />moist ccndi t ions fcr' sur..cess(:;l establtshr.u:nt. A study conducted in Arizona <br />deternined that fremonL cot.tonwood drops seed som..::ti:nc between Karch and <br />April. Wille.. (spp.) w.::!'s obsen~d to dr'Op .!leed during June. Alder, another <br />ripar[an spp.cies pres~nt along ~he Piedra River, seeds in s~ptember and October <br />at tr,e Arizona si~e (Asplund a~d Gooch 1938). T~is demonstrates that riparian <br />tree species requiring moist. bare, mineral soil have vastly di fferent seed <br />drop periods. Little is known regarding the seeding periods of other riparian <br />trees, shrubs, forns, or gra~lnolds. <br /> <br />Sar,pling along t~:e Esc~li\nt~ Rive:' in southern Ut.ah has na:Je. it pOSSible to <br />relate tree dist.rit:JUon dnd st:ccesslonal sta.tuS co!" the vegetation to geologiC <br />st.r3.t-~, river bank morpholcgy, and river flo'ol {irvine and West 1979}' The <br />E5c<,lant~ ~l'Je:- is a "rf"::lOte, ent:re~lcl"le1 river IHth few access points to <br />hur..an:<;" which is S':'I:1t::\;!1at si;,ila:" to tile- r~e::!n:.. R:.va:-. I~'Jine a:;d West found a <br /> <br />'::'har,;e ~r. SpC-2.t~.::" :Jccurrence 3nc. d.::rsiti(.s r2l;t~:::I to :"'100.0 terri~~es. The <br />\laryll1g~~s!;.r1buU~'l.<:. r::y t.errd<':~ (1.:0", werl!\l'll, a:1~ hIgh) were great.ly af:-ectej <br />by rl-:oj r..::gi!"e.s, Ai...;o. ''1 t,~.le .:::::"~ 0:" the Escal~nte R.:.ver-, ~a:1a:"ix <br />e~C!'::;'l.Chi':.e-r;::. ~.~~ "": ~(. ='v' je:.t ;::n ;'El:"~d.~e.s :':"n.: ;.'~:"e t~ss rr-=q'.le;",~ly and 1.~ss <br />sto"',,":'e:'v ir;....;~.dat....~ ...:.t:.l rlC:)dl;,,~; ~ .:::idb:- :::-r.c>Jsicn "35 reached ':iy Snyder' <br />a:,j l-':~l::;;:. (:~'j1) <br />