1Mary Power, [email protected]://ib.berkeley.edu/labs/power/office hours M,W 9-10 am, Bio 1b officeAnd by appointment2organismEcologyEcology:“oikos (house) logos (study)”: Scientificstudy of interactions of organisms withtheir environments.“Study of factors that determine thedistribution and abundance oforganisms” (Andrewartha and Birch1954)34Niemala, a Finnish ecologist, found that birch leaves wereeaten faster by caterpillars (and caterpillars grew faster)when leaves were enriched with nitrogen (as they are fromacid rain), but that trees growing for 5-10 years in outdoornitrogen-fertilized plots were less grazed than were trees inunfertilized plots…..???!???Lab results: comparedcaterpillar feeding andgrowth rates onnitrogen enriched vsnon-enriched leaves?56Unfertilized FertilizedPredatorsover-recruited tofertilizedtrees in thefield plotsplantsherbivorespredators7Methods in Ecology:• Observations• Experiments• Models8• Observations– The only way truly new information is acquired– Good natural history– Consistent long term monitoring– Nowadays: Advanced mapping, sensing, and tracing technologies• Experiments– Field or laboratory, replicated manipulated treatments with controls– Whole ecosystem experiments (lake fertilization and acidification(Schindler experiment); Hubbard Brook deforestation (Likensexperiment)• Models– verbal or mathematical simplifications of reality, intended to capturekey processes that change systems over time– Hypotheses: suggested explanations, subject to test (falsifiable)9Models, hypothesesDeduction (predictingspecific outcomes fromgeneral models)Induction (generalizing fromspecific observations tomore general models)Tests: observations or experiments10Observations: Technology and natural history: 13-17 speciesof bats in California (Bill Rainey, Dixie Pierson – husband wifeconservation biology team)- ultrasonic acoustic detection to identify(most) species and estimate collective foragingactivity11Remote sensing (e.g., airborne laseraltimetry)!Digital Elevation Modelsand predictions of environmentalconditions (e.g. light, temperatureregimes)12Airborne Laser SwathAirborne Laser SwathMapping (Mapping (LiDarLiDar))1978200613Northern California ‘melted ice cream’ topography: Landslide dominated14New sensing, mapping, and tracing technologiesTo theInternet andbeyond…15• Observations– The only way truly new information is acquired– Good natural history– Consistent long term monitoring– Advanced mapping and sensing technologies• Experiments– Field or laboratory, replicated manipulated treatmentswith controls– Whole ecosystem experiments16Mo’orea, FrenchPolynesia: pillowstars have color-matched shrimp!Berkeley students at UCBGump Marine Lab, Mo’orea1718Hypothesis 1: Diet.color derived fromfood, shrimpacquires color fromeating starfish ordiet of starfishHypothesis 2:Behavioral habitatselection. Shrimpselect colormatched starfish astheir habitat19How would you test these hypotheses?In the lab, or the field?20Transplant experiments to test whether shrimp acquirescolor from starfish or its environment or diet…Choice experiment--see if shrimp chooses starfish ofappropriate color….21SpidersGrasshoppers (Melanoplus devastator)5 plant guildsSoil moisture, NBlake Suttle, Ph.D. dissertation22Meadow food web response to doubled rainfall andchanged seasonal timing23Tools for dealing with ecological variability:• Replicates are separate (independent) units ofstudy that are treated as identically as possible,in order to assess variability that arises fromfactors we didn’t manipulate• Controls are unmanipulated units that provide abaseline for comparison, an understanding of howorganisms or systems will change over space ortime, independent of experimental treatments• Statistics tools for distinguishing signal fromnoise, e.g., test whether differences betweentreatments (e.g., control vs experimental) aregreater than differences within treatments24Patterns that demandexplanation:Marine intertidal ‘grazinghalos’(photos by Wayne Sousa)25Bird exclosures(above: Tim Woottonletter boxes, side:PVC and bird netting)Grazer exclosure: copper paint26Site preparation for nutrient diffusingx grazer excluding flower potexperiment, Tatoosh Island27Effects oflight (algalproductivity)on river foodwebs5 light levelsX 5 replicates= 25 channels28Effects ofnutrients andanimals on algalaccrual in riversJaneMarksNorthernArizonaUniv.29Replication may be difficult or possibleat whole-ecosystem scalesDavid Schindler, experimental lakes: added C, N, and P(pea green, eutrophied lake) vs C and N (blue lake)30• Experiments– Field or laboratory, replicatedmanipulated treatments with controls– Whole ecosystem experiments Schindler’s lake fertilization andacidification (p. 1205, Fig. 54.8 inCampbell); Hubbard Brookdeforestation31• Observations– The only way truly new information is acquired– Good natural history– Consistent long term monitoring– Advanced mapping and sensing technologies• Experiments– Field or laboratory, replicated manipulated treatments with controls– Whole ecosystem experiments (Schindler’s lake fertilization andacidification, p. 1205, Fig. 54.8 in Campbell); Hubbard Brookdeforestation• Models– verbal or mathematical simplifications ofreality, intended to capture key processesdriving system change over time– Hypotheses: suggested explanations,subject to test (falsifiable)32Models, hypothesesDeduction (predictingspecific outcomes fromgeneral models)Induction (generalizing fromspecific observations tomore general models)Tests: observations or experiments33Understanding ecological patterns and processesrequires both:Reductionist approaches -- seeking mechanisms,causal processes—(e.g., caterpillars feed and growfaster on nitrogen rich leaves) (lab—spoon vs chopstick feeders—mechanism affects efficiency)andHolistic approaches -- determining boundaries of thesystem (all that must be included) necessary forunderstanding and predicting outcomes of ecologicalinteractions in the real world. (lab—how do diets,experience, environmental context affect success andeventual composition of foragers on VLSB lawn? )Zoom lens ecology: focus in for mechanism, zoom outfor context and consequences34Taxon2 speciesFood chainStrong interactions35Taxon or guild2 speciesFood chainStrong interactionsspacetimeenergy36EnvironmentLecture 2.Climate, microclimatesand
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