|
WATERSHED RESTORATION
<br />B. Kauiimin
<br />:fin e~tllllatCd il)~i-~~O~r Ut dll 11atLll'al 17parlall dl'eaS 111
<br />tf~c Cnited St~1tc~ 11a~ c been extc»si~-el~~ altered (Hirsch
<br />~,~i `;e~•el~iui>t f~~-S); ~Iphn~xim~t~i1~ -l:. ~ million ha
<br />! I - nliliion acre) car ~3' < <~E Ill ~~5. ~~-sands hate been
<br />_: ~incc cLe 1 ~ ~~l> ! D~~hI 1~~~>I7). dome ~~ i~lespread land
<br />_:~~'~ plat OG=L1r 171 b(lt]1 U~~l;lll~iti ,?Illi r;plrlan 5CStellls
<br />_~e~-t t11~~;r ,re<~:e-~t im~~acls o:1 ~t,e,l;rside areas. For ex-
<br />_. ~~~ :i,_ . i tre~._~.. ~t:1'._ , .i~~~~~~~"; gazing is per-
<br />_._. , , ._~ -..,._ ,-: million ha
<br />:.~:_.. _.. . - ~ - - ~_ -~ .- .__.. .~. ..._ 1~,~lllellt-
<br />~. ~ ~ ~ - ~ ~ ~ ~ _ _~ _~ ~ _~~ poor
<br />r~,t to
<br />- '.. ~ _~ ~----~ - ~ _. .~::-~~I'azlllg
<br />~,:-; -~
<br />_ ..~~ ~~raz-
<br />_.._ .._
<br />~n rlore
<br />~~ ~ -~ _ - ~..~'it)0 miles)
<br />- _..._ - ~~ - _ _ _:_~ut~• as a
<br />_.. _. ..._ ~. _ _ _.__ ~_. l~)~)1).
<br />__. _, .. _,_..., ~ .. :~~...,.... ~..~ ._...~ ..~~m~ dimin-
<br />e func-
<br />~~_.,_, 1!1C;lIQiI1;; t!lc ~A~~ll1~ cinCi :~"C~"'~~_i[ tranStOl'nla-
<br />', ~~:.-~..,_,._ , r,r,ri;c<~lit~n cif ~~~~,1t~~r, ~1t;ulttation of
<br />,~u~i~. ;-.:,;:;r~r,ance cif ~~r~~am r1ut~~: ;.;,~i ~treanl tem-
<br />___._. _._._, .~~~?~, ~1'.,, "l`U 11~_,, ~lEc'.", .~ilQ l'stabhsh-
<br />~_:_.- _..._...,,.__,_~E1~,_.~~ ~ ~t _...~ ~._~. -"' - -. and ~~°ildlife.
<br />- , . ~~ - -, _..._.~... ~~~:~, --~ -___ _. =.ledecline
<br />.-_~ _. _ . _._ - , _ .. _ ~ , . _._-_ ~.dation of
<br />__.._ - " ._ .__._ _ _~._~_. _ -~ --~ ;-~~cies, and
<br />~~ ~ ~ _:_: ~ ~- ~ -!~1~- of the
<br />-~~cted by
<br />~„ ,
<br />bank erosion, and channelization (National Research
<br />Council 1992). More than half of the nation's rivers have
<br />fish communities harmed by turbidity, high tempera-
<br />tures, toxins, and low levels of dissolved oxygen (Coun-
<br />cil on Environmental Quality 1989). Almost 85% of his-
<br />torical Pacific Northwest anadromous salmon stocks
<br />are either extinct, endangered, threatened, or of special
<br />concern (National Research Council 1996). The current
<br />threat to aquatic biodiversity in North America is greater
<br />than the threat to terrestrial diversity (Naiman et al.
<br />1990. While 11 ~'~~-15~7~ of the terrestrial vertebrates are
<br />considered rare or nearly extinct, 34~7~ of the fishes,
<br />~5`ic of the crayfishes, and %5~'~ of the bivalve mussels
<br />fall into these categories (\?aiman et al 1990. To date,
<br />not a single aquatic species has been delisted through
<br />Endangered Species Act procedures because of imple-
<br />mentation of a successful recovery plan; in fact, the
<br />majority of the listed species do not have a formal
<br />recovery plan (Williams et al. 1989). An unprecedented
<br />need exists for ecological restoration of riparian ecosys-
<br />tems and their closely associated aquatic ecosystems.
<br />What Is Eco(ogicat Restoration?
<br />Ecological restoration in riparian ecosystems is de-
<br />fined as the reestablishment of predisturbance riparian
<br />functions and related chemical, biological, and physi-
<br />cal processes (National Research Council 1992). Res-
<br />toration is the process of repairing damage caused by
<br />humans to the diversity and dynamics of indigenous
<br />ecosystems (Jackson et al. 1995). While ecological
<br />restoration attempts to return riparian zones as closely
<br />as possible to predisturbance functions and processes,
<br />scientists must recognize that ecosystems are in a con-
<br />stant state of flux due to ever-changing environmental
<br />conditions. These changes, sometimes coupled with
<br />irreaersible human impacts (e.g., soil loss, biotic inva-
<br />sions, air pollution), may preclude our capability to
<br />precisely re-create ecosystem structure and functions
<br />that previously existed. Thus, the goal of restoration
<br />projects is to ensure that the dynamics of natural eco-
<br />system processes are again operating efficiently so that
<br />both ecosystem structure and function can be recovered
<br />(National Research Council 1992).
<br />Riparian areas are three-dimensional zones of bio-
<br />logical, physical, and chemical interactions between
<br />terrestrial and aquatic ecosystems (Gregory et al. 1991).
<br />Because of landscape-level interactions between terres-
<br />trial and aquatic systems, ecological restoration of
<br />riparian zones requires a holistic approach whereby
<br />activities and conditions across an entire watershed
<br />should be considered. Problems affecting riparian and
<br />aquatic resources are unlikely to be solved by ignoring
<br />deleterious land management practices, either historical
<br />or current, that occur at landscape or watershed scales.
<br />While scientists strongly recognize the need to re-
<br />store or conserve native fish throughout the Pacific
<br />\'orthwest and other nearby regions, less appreciation
<br />exists for how local geomorphic settings and natural ~
<br />=_aal Issue on batershed Restoration
<br />Fisheries • 13
<br />
|