Power of observation Observational vs. experimental studies Direct measures vs. indices Data sheet...
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Transcript of Power of observation Observational vs. experimental studies Direct measures vs. indices Data sheet...
• Power of observation• Observational vs. experimental studies• Direct measures vs. indices• Data sheet basics• Sampling• Tools/Techniques--overview
Tools and Techniques - Overview
Ecological Methodology LEC-01 Althoff
Power of Observation
• Knowing what, when, where, and how to look for the needed information
• Requires ____________ of the species (biotic) and physical environment (abiotic)….and knowledge of the __________________ _______________ being used to make those observations
Power of Observation
• Requires practice: “keen eyes, ears, touch, etc.”
• Requires proper recording….including “____________” or “___________” observations. Separate “facts” from “interpretations”
• Avoid __________________ based on inadequate information
Power of Observation & Recording
• Key question: what to record?• Trust nothing to memory:
a) write it downb) record it on tapec) enter it into a data loggerd) capture it via picture/video
• Use standardized data sheets (for consistency…but don’t hesitate to record the trivial.
Observational vs. Experimental Studies
• Observational: _________ (usually), trying to determine basics, learn patterns, trends, characteristics
• Experimental: ________ (usually), have basic knowledge of subject that enables one to “separate” into treatment groups
Observational vs. Experimental Studies
• Observational: generally summarize data using _______________ statistics
• Experimental: determine if differences between treatments are “real” using ______________ statistics
Statistics • Descriptive statistics: central tendency: mean,
median, mode spread: range, variance, standard deviation, standard error
• Inferential statistics: t-test, sign test, Kruskal-Wallis test, F-test, Analysis of Variance (ANOVA), Friedman test….some are parametric, some are non-parametric
• Models: Akaikae Information Criterion (AIC),Structural Equation Modeling (SEM)
Direct Measure (estimates) vs. Index
• Direct measure: length of hind foot,mass (wt.), color of fur, contents of stomach, N content of feces, height of vegetation, stage of leaf-out, etc.
• Index: “some approximation” of what is exactly there. Assumes that the “index” is a true reflection of the actual measure.
Direct Measure TO PRODUCE AN Index• Sometimes, take a “direct” measure but use it
to produce an index:ex: measure fat around the kidney
as an indicator of overall body condition (weigh the fat, weigh thekidney): kidney fat index
ex: monitor breeding behaviors of birds to estimate proportion ofadults suspected of nesting andproducing young: reproductive success index
Data Sheet Basics
• Keep it simple• Date, time “slots”• Sequence on sheet for data entry should
match the “procedure” whenever possible• Use check boxes:
a) “repeated”/standard entriesb) avoiding lots of writingc) consistency
• Back-up/make copies of data !!!!!
Data sheet examples
Sampling
• Three basic types: randomsystematicstratified
Where are you? _____ = global positioning system
$200-600+/- 10 m accuracy $5,000 – 6,000
+/- 0.1 m accuracy
Locational/Directional “Tools”
• Compass• Topographic maps (“topos”)• Hand-drawn maps• Altimeter• Etc.
• GPS: position (on the face of earth, including altitude): UTM coordinates = X-Y coordinates
GPS / GIS
• Need GPS data to feed into GIS • _____ = geographical information system• Produce “layers”• Produce maps• Evaluate data ____________!!!• Satellite imagery reaching finer and finer scale:
was 3 m x 3 m resolution…almost commercially available at 1m x 1m or less
• Cautions: 1) garbage in, garbage out 2) “boots” on the ground
observations still needed
Cover boards
woodmetal
Monitor: salamanders snakes macroinvertebrates
Cover boards
Traps “box type”
Live capture (and release)
Monitor small mammalsa) Presence/absenceb) Species richnessc) Popn estimation (i.e., mark-recapture)
Sherman live-trap (H.B. Sherman)
cage trap
Pitfall traps
Monitor:a) small mammalsb) amphibiansc) arthropods (ex. beetles)
Mist nets
Nest boxes
Trip/Trail Cameras
Trip/Trail Cameras
• _____________ method• Constant monitoring or program to sample at
certain times• “Captures” the individual(s)… ID
individuals sometimesDate and time stamps (temp, too,?)Archive data
Visual Obstruction “Readings” (VOR)Robel Pole: in grassland habitat, high degree of correlation between “height” and biomass (vegetative) present
Robel PoleNudds Board
Daubenmire Frame Estimate % cover (vegetation?)
Estimate % bare ground (abiotic)
Sampling “frames”
• Daubenmire frame: 10 cm x 20 cm• Meter frame: 2.0 m x 0.5 m or
1.0 m x 1.0 m= 1 m2
• Estimate coverage: 0-5, 5-10, 10-25, 25-50, >50
• Estimate species density
• Estimate species richness
Sampling: Lines & Points
• Line transectcount plant
species on line or plants every 10 m,
measure distance coverage, etc.
• Distance sampling• Point-centered
Distance Sampling
• Work off of line transect• Measure distance individual (plant, animal,
bare ground, nest, etc.) is from the line• Software program DISTANCE can help
estimate density with confidence intervals (direct measure…not an index…to population density to measure abundance)
Point Center Sampling
• Bird counts using this approach known as “point counts”
• Plant/tree sampling using this approach that uses points is called “point-centered quadrats”
Point counts
-hear or see bird
Canopy Cover
_____________________(index to either lightpenetration and/or overhead cover…ordirect measure if photograph & analysis)
Tree sizes: DBH = diameter breast height
Biltmore stick
DBH tape
Distance to or height of an object: range finder
+/- 1 m accuracy for this type.
GPS unit could serveSame function if take 2 points
Finer scale: Fat-max it (+/- 0.02m…1/16”)
Soil Probes:measuring physical environment:
bulk density (soil compaction)pHN, C, etc.
Measuring biotic environment:nematodes (roundworms)annelids (earthworms)
Radiotelemetry: VHF & GPS units
Radiotelemetry…advantages include
• “Follow” the same individual “everywhere”• “Follow” the same individual at any time• Can minimize observer bias…but limitations, for
example: collar too tight, too heavy, too easy to be “restrictive”, and issue with
‘social’ species• Can generate “lots of data”
Sampling Arthropods
Kill jars
Sweep nets lights & sheets
Secchi Diskmeasuring physical environment:
“transparency” = turbidity, usually to the nearest 1 ft or. 0.25 m
Bottom sampler (substrate) “___ bottom sampler”
Pokar dredgeEckman dredge
Kick seines
Measuring biotic environment, by capturing: macroinvertebrates fishes turtles etc.
Substrate plates (Hester-Dendy multi-plate samplers)
Measuring biotic environment, by capturing: “small” macroinvertebrates that will “adhere” to the plates. Usually leave in water for ____ weeks
Electro-shockersStuns fish, fish rise to surface, net fish and then process….
Can: ID to species remove scale (to
age) release or harvest
___________ sampling(abiotic environment)
________or ________ (generally done in the field with ‘fresh’ samples)…otherwise use meter or take to lab
Aging and Sexing
Hair snares(using barbed wire or sticky substance)
•non-invasive•determine species (visual inspection or DNA)•If “really good”, individuals
Fecal Matter = Scats & Pellets
Fecal Matter = Scats & Pellets
Fecal & Urine Samples…
• Non-invasive sampling• Determine food habits• Determine presence/absence• Determine nutritional status (including N
content of diet)• Determine species, sometimes individuals• Determine reproductive status
Lots of room for innovation…
• Sampling/observing “something” different may require different method and/or equipment
• New technologies provide now opportunities (ex. barcodes)
• But….equipment still has limitations. Good field biologist ________ forget that!