ENVS 202 1st Edition Lecture 3Outline of Last Lecture I. Review of Feedback LoopsII. Willamette Valley, Then and NowOutline of Current Lecture I. Willamette Valley Land UseII. Salmon in the PNW Case StudyIII. Salmon: Life History and EvolutionCurrent LectureI. Willamette Valley Land UseFrom 1850s-1990s: upland forest regrows, major switch from savanna to urban/agricultureThis was a major shift for salmon living in this area of the Willamette RiverEven more change throughout time is expectedTrend expected is more loss of natural habitat, more loggingConservation 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 lifeII. Salmon in the PNW Case StudyCentral focus for conservation efforts deals with watershedsSalmon begin/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 onThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Trees 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 Washington, Oregon, and Idaho 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 salmonIII. Salmon Life History and EvolutionIn a typical watershed, different types of salmon are based in different areas and types of the river4 H’s (of how humans have affected salmon): harvest, hatcheries, hydropower, habitatIn all coastal regions (except Alaska) salmon populations have decreased significantlyESU: Evolutionary Significant UnitsCurrently there are nine 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 life Pesticides 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 salmonFirst life appearing on EarthFree oxygen in the atmosphere (2000 mya)Bony fish evolve (400 mya)Salmon evolve (100 mya)Cascades form (15 mya) What sets salmon apart?Very efficient respiratory system and musculature that permits rapidityAnadromous: they spawn in freshwater, mature in oceansThree kinds of evidence suggest that salmon began in freshwater1. Earliest salmon fossils are in freshwater systems2. Their most closely related groups are freshwater fish3. They spawn in freshwater (spawning habits tend to evolve more slowly)Challenges of going from freshwater to salt waterOsmoregulationBody coloration Behavior (massive spatial change)Why do they do this? Oceans became cooler and more productive ~25-8 mya and had richerfood than freshwater, this makes salmon bigger and more apt to spawn