Primerjava sestave geomorfoloških enot struge reguliranih in nereguliranih odsekih reke Soče
Povzetek
Namen članka je ugotoviti vpliv regulacije pretoka vode v reki Soči na tipe, velikost, prostorsko porazdelitev in povezanost geomorfoloških enot struge (GES). Raziskavo smo opravili na treh odsekih reke, tj. na nereguliranem odseku (odsek 1) in na dveh reguliranih odsekih z zmanjšanima pretokoma vode (odseka 2 in 3). Vse tri odseke vodotoka smo prehodili ob oziroma v strugi, z majhnim čolnom pa smo prečkali neprebrodljive odseke. Ocenjevanje na terenu je obsegalo kombinacijo vizualnih in fizičnih meritev.
Rezultati so pokazali znatne razlike v sestavi GES med reguliranimi in nereguliranimi odseki reke. Na nereguliranem odseku reke Soče so prevladovali gladki tokovi in habitati z značilno hitrim vodnim tokom, medtem ko so na reguliranih odsekih reke Soče prevladovali tolmunski tipi GES s počasnim vodnim tokom. Zaradi odvzemov vode in s tem zmanjšanih pretokov reke na odsekih 2 in 3 je prišlo do znatnega zmanjšanja v povprečni širini omočenosti struge v primerjavi z nereguliranim odsekom (na 31,8 % in 50,4 %). Še večjega pomena je dejstvo, da je v reguliranih odsekih reke naraslo povprečno število GES na km. Rezultati raziskav predstavljajo osnovo, na podlagi katere lahko razlagamo podatke o kartiranih habitatih ter interpretiramo velikost in fragmentacijo habitatov vzdolž zaporednih odsekov reke. Rezultati študije so pokazali, da je regulacija pretoka reke Soče vplivala na spremembo prevladujočega tipa GES, znatno zmanjšala velikost GES in vplivala na dolžinsko razporeditev tipov GES. Zmanjšala se je povezanost habitatov, fragmentacija habitatov pa se je povečala. V prihodnosti je potrebna izvedba raziskav, ki bodo prispevale k boljšemu razumevanju odnosov med dinamiko fizičnega habitata in združbami oranizmov v vodotoku.
Prenosi
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