Biodiversity Guide - The Intertwine

egional conservation strategybiodiversity guideChapter 7 Threats and ChallengesUse and Effectiveness of Wildlife Crossings:National Wildlife Crossing Decision Guide ProtocolJ.A. Bisonnette and P. Cramer. NCHRP 25-27.2007. National Academy of Sciences and Engineering,Transportation Research Board, NationalCooperative Highway Research Program.“Quantifying the Road-effect Zone: ThresholdEffects of a Motorway on Anuran Populations inOntario, Canada”F. Eigenbrod, S.J. Hecnar, and L. Fahrig. Ecologyand Society [online] 2009;14:Article 24.“Estimate of the Area Affected Ecologically by theRoad System in the United States”R.T.T. Forman. Conservation Biology 2000;14:31-35.“Behavioral Barriers to Non-migratory Movementof Birds”R. Harris and M.J. Reed. Ann Zool Fennici2002;39:275-290.Final Report on Oregon Wildlife LinkageWorkshops Hosted by ODFW in 2007A. Hatch, S. Wray, S.L. Jacobson, M. Trask, andK. Roberts. 1-23. 2007. Salem, Oregon, OregonDepartment of Fish and Wildlife.Wildlife Crossings: Development and Field Test ofMethods for Assessing Corridor Permeability in thePortland Metropolitan RegionK. Keller. Thesis dissertation, 2009. Portland, OR,Portland State University.Highway Median Impacts on Wildlife Movementand MortalityA.P. Klevinger and A.V. Kociolek F/CA/MI-2006/09, 1-128. 2006. Sacramento, CA, Stateof California Department of Transportation.Green Trails: Guidelines for EnvironmentallyFriendly TrailsMetro Regional Government. 2004. Portland, OR.Wildlife Crossings: Providing Safe Passage forUrban WildlifeMetro Regional Government. 2009. Portland, OR.“A Southern California Freeway Is a Physical andSocial Barrier to Gene Flow in Carnivores”S. Riley, J.P. Pollinger, R.M. Sauvajot, E.C. York, C.Bromley, T.K. Fuller, and R.K. Wayne. MolecularEcology 2006;15:1733-1741.“Limitations to Wildlife Habitat Connectivity inUrban Areas”M. Trask. In C.L. Irwin, D. Nelson, and K.P.McDermott, International Conference on Ecologyand Transportation. Proceedings of the 2007International Conference on Ecology and Transportation.2007. Raleigh, NC, Center for Transportationand the Environment, North CarolinaState University.“Assessing Functional Landscape Connectivity forSongbirds in an Urban Environment”M. Tremblay. In C.L. Irwin, P. Garrett, and K.P.McDermott. Proceedings of the 2005 InternationalConference on Ecology and Transportation.2005. Pp. 561-564. Raleigh, NC, Centerfor Transportation and the Environment, NorthCarolina State University.“Road Crossing Structures for Amphibians andReptiles: Informing Design through BehavioralAnalysis”H. Wolz and Gibbs. In C.L. Irwin, P. Garrett, andK.P. McDermott. Proceedings of the 2007 InternationalConference on Ecology and Transportation.2007. Raleigh, NC, Center for Transportationand the Environment, North Carolina StateUniversity.Water QualityLori Hennings, MetroHistorically, forest was the predominant landcover in the greater Portland-Vancouver region.Clearing for agriculture, followed by increasingurbanization and rural residential development,has markedly influenced overall water quality.Scientific research shows that water qualityresponds predictably to changes in land cover,typically declining as tree cover is removed andthe amount of hard surfaces increases. Comparisonsof land cover to overall stream healthsuggest that streams in the region have followedthis general pattern.Clark County – Clark County DES PerspectiveThe 2010 Clark County Stream Health Report(Clark County Department of EnvironmentalServices, 2010) indicates that many Clark Countystreams are moderately to severely degraded.The report analyzes aquatic health in 10 countydefinedwatershed areas using water quality, biological,and stream flow indicators. The analysisis based on a significant amount of data collectedsince 2004, including nearly 900 water qualitysamples, 125 samples of aquatic invertebrates, and19 continuous stream flow gages.Forest cover and riparian vegetation conditionstrongly influence stream health issues inClark County. Stream temperature issues areubiquitous and typically stem from lack of shadeand low summer stream flows. Channel erosionand habitat loss caused by altered stream hydrologyis compounded by insufficient streamsidevegetation and loss of instream woody debris.Inadequate riparian areas contribute to increasedturbidity and fecal coliform bacteria pollution.The report recommends protection and rehabilitationof forest and riparian zones as criticalcomponents in improving stream health.Overall stream health at the county watershedscale is summarized in Table 7-1. For detailedresults at a scale covering 78 county subwatersheds,the complete 2010 Clark County StreamHealth Report is available at http://www.clark.wa.gov/water-resources/watersheds.html.Condition of Individual Watersheds inClark CountyA summary of conditions and conservation issuesin each watershed in the RCS area is provided inAppendix I.West Slope WatershedSubwatersheds in the West Slope range from 18to 38 percent forest and 11 to 25 percent hardsurface. Significant additional urbanization isexpected in the future. Water quality, biologicalhealth, and flow all are rated as poor. Water qualitystudies indicate widespread issues, includingfecal coliform bacteria and elevated turbidity.Salmon Creek WatershedSubwatersheds in Salmon Creek range from 7to 68 percent forest and 10 to 51 percent hardsurface. This watershed contains some of themost urbanized and least urbanized areas in thecounty, with significant additional urbanizationexpected. Salmon Creek also contains some ofthe least healthy and most healthy subwatershedscountywide. Water quality and flow are ratedas fair, with biological health rated as poor. Thewatershed has temperature, fecal coliform, andturbidity issues.East Fork Lewis River WatershedSubwatersheds in the East Fork Lewis Riverrange from 20 to 90 percent forest and 4 to 20percent hard surface. The upper watershed isprimarily forested, while the middle and lowerwatershed has mostly been cleared for agricultureand development. Water quality and biologicalhealth are rated as fair, and stream flow is rated asgood. Water quality studies indicate issues withfecal coliform bacteria, particularly in the lowerwatershed.North Fork Lewis River WatershedSubwatersheds in the North Fork Lewis Riverrange from 39 to 75 percent forest and 3 to 14percent hard surface. Timber management continuesto be the primary land use, and very littlefuture urbanization is expected. Water qualityis rated as good and biological health as fair. Nostream flow data are available. Cedar Creek hasstream temperature issues.128 129