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BIOL 4240 Field Ecology

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?.

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BIOL 4240 Field Ecology

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  1. BIOL 4240Field Ecology

  2. Which way did they go? Ecologists are often interested in spatial data… Plant ecologists, distribution of individuals. Animal ecologists, distribution of individuals AND movements

  3. Which way did they go? What purpose can movement/telemetry studies serve? * Movement patterns, migration, dispersal * Space use and home range size * Resource use and selection * Population abundance and density * Survival * Fecundity

  4. Which way did they go? • Movement patterns – assumed to be random through homogenous environment

  5. Which way did they go? • Home ranges – Various models (polygons, parametric and non-parametric)

  6. Which way did they go? • Home ranges – Various models (polygons, parametric and non-parametric)

  7. Which way did they go? • Home ranges – Various models (polygons, parametric and non-parametric)

  8. Which way did they go? • Home ranges – Various models (polygons, parametric and non-parametric)

  9. Which way did they go? • Home ranges – 2 variables have big influence… • How many animals • How many points per animal

  10. Which way did they go? • Resource use/selection – Describe habitat with discrete categories… • Cover type • Vegetation types • Topography • Successional stage

  11. 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

  12. Which way did they go? • Survival – • Use computer software SURVIV by White (1983) • Program MARK? • Various other methods… Mayfield, Kaplan-Meier, Cox’s

  13. Which way did they go? • Questions necessary to determine… • What type of study? *Observational (descriptive or correlative) • *Manipulative

  14. Which way did they go? • Questions necessary to determine… • Hypothesis testing or Model building? *Which type of study is more appropriate for model building?

  15. Which way did they go? • Questions necessary to determine… • What level of inference? • What is the population? • Time of day? • Scale?

  16. 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

  17. 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

  18. 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)

  19. 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

  20. Which way did they go? • Questions necessary to determine… • Are location errors addressed? • *PDOP • *Remote estimation

  21. Which way did they go? • Questions necessary to determine… • Are biases in observation rate identified and corrected? • *remote estimation (GPS collars etc.) important

  22. Which way did they go? • Preliminaries… • How many dimensions do tracking data have?

  23. Which way did they go? • Coordinate Systems…Explain UTM and why it is preferred • *Advantages of Lat./Long.? • *Disadvantages?

  24. Which way did they go? • Coordinate Systems… Explain UTM and why it is preferred • *Universal TransverseMercator (UTM)…between 84 N and 80 S divided into 6° rectangles (zones 1-60)...

  25. 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

  26. Which way did they go? • Coordinate Systems… * N or S then UniversalPolar Sterographic (UPS) used.

  27. Which way did they go? • Preliminaries… • What other data are important to include with location data?

  28. Which way did they go? • Preliminaries… • Cause and Effect can ONLY be determined through which type of experiment?

  29. 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?

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