This preview shows page 1-2-3-4 out of 12 pages.

View Full Document
View Full Document

End of preview. Want to read all 12 pages?

Upload your study docs or become a GradeBuddy member to access this document.

View Full Document
Unformatted text preview:

ENVS 202 1st EditionExam # 1 Study Guide Lectures: 1 - 9Lecture 1 (January 8th) – Shifting Baselines and Feedback LoopsShifting Baselines are “the new normal” in contrast to what has changed over time, what may seem pristine today is really far less than in the pastOverfishing and depleted coral reefs are good examples, even if today’s levels of fish or coralref biodiversity seem good, they are very low compared to our baseline (year 1800 or so)The Tragedy of the Commons refers to common resources shared by all, their overuse and mistreatment become a tragedy (examples are the ocean and the atmosphere)Feedback Loops: many are interconnected in a domino effectPositive: self-reinforcing loops, an increase in one variable leads to further increase in that variable or decrease leads to further decreaseA feedback loop being positive has nothing to do with whether it is beneficial or notNegative: self-regulating loops, a system will balance itself outMost predator/prey are negative feedback loops: the more predators, the less prey; the more prey, the more predatorsExample: fossil fuels are produced -> greenhouse gases are produced -> Earth warms -> more clouds -> clouds reflect more sunlight -> Earth coolsLecture 2 (January 13th) – Willamette RiverWillamette Valley: Then and NowForests: from- savanna-like hills, extensive along the river; to- dense in hills, replaced with other land uses along the river; impact: oak/scrub reproduction boomsAgriculture: from- none, land was used as needed, techniques for ‘farming’ primary food sources were natural (fire); to- what most of the area is used for, major land use; impact- land goes from natural prairies and savannas to agriculture and industry, there is habitat loss, air pollution, and fossil fuel consumptionWillamette River: from- wider, less controlled, complex; to- channelized river which lacks complexity; impact- some river habitats were eliminated, greater potential for impact on human structuresWetlands: from- extensive, dominating; to- replaced with agriculture or urban lands; impact-more land is available, loss of this habitat, loss of the filtration and absorptionNative Prairie: from- all of the land, carefully maintained by Natives, dominated by tall grasses and fertile soil; to- land now dedicated to agriculture, minimal prairie; impact- oak and scrub reproduction booms without the fires, land is farmed by industryRiparian Vegetation: from- dense, extensive; to- patchy, conifers mostly removed; impact- loss of habitat for riparian species, increased water temperature, impaired water qualityFish/wildlife Habitat: from- natural state, all natural growth of riparian area, high oxygen; to-much smaller, less vegetation, likely pollution increase with surrounding pesticide/herbicide-using farms; impact- decline of susceptible aquatic species, difficult/expensive to produce clean waterLecture 3 (January 15th) – Willamette Valley and Salmon LifeWillamette Valley Land Use: from 1850s-1990s, upland forest regrows, major switch to urban/agriculture; this was a major shift for salmon living in the areaMore change throughout time is expectedTrend expected is more loss of natural habitat, more loggingConversation initiatives are working to restore forests and upland savannasLarge debate about which baseline to use in restoration efforts: restoring to 1850s-land may not necessarily be beneficial to our present-day lifeConservation efforts for salmon in the PNW deal with watershedsSalmon begin and end life, spawn in rivers, and depend greatly on an appropriate amount of sediments to incubate eggs; too much is too muddy, too little is all bedrockOrganic matter and other plants attract insects that the salmon feed onTrees in streams provide smaller and less turbulent niches for salmon to lay eggs out of the currentSalmon’s dead bodies attract other animals that are part of the watershed214 stocks of salmon or trout from OR, WA, and ID are at riskSalmon benefit from and provide benefits to their ecosystemsSalmon stocks adjust specifically to the river they will return to, problems arise when these rivers are changing from pesticides, herbicides, etc.Types of SalmonChum: spawn above tidewater except in large riversPink: spawn in tidal areas ~40 miles upstreamCoho: spawn in smaller coastal tributariesChinook: spawn in lower river reaches above the tidewaterSockeye: often live in land-locked bodies of waterSteelhead: can spawn multiple times, unlike other kinds of salmonIn a typical watershed, different types of salmon are based in different areas and types of the river4 Hs (of how humans have affected salmon): harvest, hatcheries, hydropower, habitatIn all coastal regions (except Alaska) salmon populations have decreased significantlyESU: Evolutionary Significant Units, there are 9 endangered Chinook ESUsWhat have we done to mitigate abundance drops? Release of hatchery raised fish, but these areusually just one stock- diversity diminishes, these fish are not as apt for wild lifePesticides from farms seep into soil and travel to rivers and streams They affect fish both directly and indirectly; they may eliminate salmon’s prey and may makethem unable to spawnLife events that influenced salmon: first life appearing on earth, free oxygen in the atmosphere (2000 mya), bony fish evolve (400 mya), salmon evolve (100 mya), cascades form (15 mya)What sets salmon apart? They have very efficient respiratory systems and musculature that permits rapidity, they are anadromous (spawn in freshwater, mature in oceans)Three kinds of evidence suggest that salmon began in freshwater: 1. Earliest salmon fossils are in freshwater systems, 2. Their most closely related groups are freshwater fish, 3. They spawn in freshwater (spawning habitats tend to evolve more slowly)Challenges of going from freshwater to salt water: osmoregulation, body coloration, behavior (massive spatial range)Salmon go to oceans because oceans became cooler and more productive ~8-25 million years ago, and had richer food than freshwater, this makes salmon bigger and more apt to spawn moreLecture 4 (January 20th) – LTWC and SalmonLong Tom River enters the Willamette River north of MonroeLong Tom Watershed accounts for 410 square miles of waterLand use is a mix of urban, agriculture, rural, residential, and forestryThere is a population of about 15000 people benefit from the Long Tom WatershedLong Tom Watershed Council’s mission: improving quality and quantity through


View Full Document
Loading Unlocking...
Login

Join to view Exam 1 Study Guide and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Exam 1 Study Guide and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?