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BIOL 4240 Field Ecology. Which way did they go?. Ecologists are often interested in spatial data… Plant ecologists, distribution of individuals. Animal ecologists, distribution of individuals AND movements. Which way did they go?. What purpose can movement/telemetry studies serve?. - PowerPoint PPT Presentation
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BIOL 4240Field Ecology
Ecologists are often interested in spatial data…Plant ecologists, distribution of individuals.
Animal ecologists, distribution of individuals AND movements
Which way did they go?
What purpose can movement/telemetry studies serve?
Which way did they go?
* Movement patterns, migration, dispersal* Space use and home range size* Resource use and selection* Population abundance and density* Survival* Fecundity
• Movement patterns – assumed to be random through homogenous environment
Which way did they go?
N
10 Random WalksMinimum Convex PolygonObserved Movement Path
1 0 1 2 Kilometers
• Home ranges – Various models (polygons, parametric and non-parametric)
Which way did they go?
• Home ranges – Various models (polygons, parametric and non-parametric)
Which way did they go?
• Home ranges – Various models (polygons, parametric and non-parametric)
Which way did they go?
• Home ranges – Various models (polygons, parametric and non-parametric)
Which way did they go?
• Home ranges – 2 variables have big influence…1) How many animals
2) How many points per animal
Which way did they go?
Confidence level (%)
Bound (%)
N necessary
95 10 386
95 20 98
95 30 45
• Resource use/selection – Describe habitat with discrete categories…– Cover type– Vegetation types– Topography– Successional stage
Which way did they go?
Which way did they go?
• Population Abundance & Density –
– Use telemetered animals as “marked”– Use tagged animals to determine
visibility bias for aerial surveys… helps to minimize underestimation that is common
Which way did they go?
• Survival –
– Use computer software SURVIV by White (1983)
– Program MARK?– Various other methods…
Mayfield, Kaplan-Meier, Cox’s
Which way did they go?
• Questions necessary to determine…
– What type of study?
*Observational (descriptive or correlative)
*Manipulative
Which way did they go?
• Questions necessary to determine…
– Hypothesis testing or Model building?
*Which type of study is more appropriate for model building?
Which way did they go?
• Questions necessary to determine…
– What level of inference?• What is the population?• Time of day?• Scale?
Which way did they go?
• Questions necessary to determine…
– What is the sample/experimental unit?
*Location point/data
*Animal
* Social considerations
AVOID pseudoreplication (dependence or correlation of sample units, and artificially high estimates of precision) to minimize > type I error
Which way did they go?
• Questions necessary to determine…
– Sampling design?
– Sampling intensity?• Preliminary estimates of means/variances• Determining biological significance• Choosing desired power• Calculating necessary N
Which way did they go?
• Questions necessary to determine…
– Sampling design?
– Sampling intensity? *Studies suggest that 20-25 animals with ~50 pts
necessary for determining resource selection… AND
*50-300 pts /animal necessary for home range size(Rowland et al. 1997, 1998)
Which way did they go?
• Questions necessary to determine…
– Are Radio-marked animals an unbiased sample?*Effects of non-random capture*Marking-induced or relocation-induced changes in
behavior and survival
Which way did they go?
• Questions necessary to determine…
– Are location errors addressed?*PDOP*Remote estimation
Which way did they go?
• Questions necessary to determine…
– Are biases in observation rate identified and corrected?
*remote estimation (GPS collars etc.) important
• Preliminaries…
– How many dimensions do tracking data have?
Which way did they go?
• Coordinate Systems…Explain UTM and why it is preferred*Advantages of Lat./Long.?
*Disadvantages?
Which way did they go?
• Coordinate Systems… Explain UTM and why it is preferred*Universal Transverse
Mercator (UTM)…between 84 N and 80 S divided into 6° rectangles (zones 1-60)...
Which way did they go?
• Coordinate Systems… Explain UTM and why it is preferred* Example… zone 1 = 180 W Prime meridian = 177 W)
* What are the units in a number AND what do they convey regarding precision?0291923, 4441087 vs. 0291, 4441
Which way did they go?
• Coordinate Systems… * N or S then UniversalPolar Sterographic (UPS) used.
Which way did they go?
• Preliminaries…
– What other data are important to include with location data?
Which way did they go?
• Preliminaries…
– Cause and Effect can ONLY be determined through which type of experiment?
Which way did they go?
• Preliminaries…
– Considerations for radio tags…– Smallest size possible– Cryptic coloration– Transmitter effects on behavior/fitness– Requisite time for adaptation– Critical life history periods to avoid– Others?
Which way did they go?
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