Monday 2/24

2. Monday 2/24 • Pop Quiz #6 • Review Prickly Pear math questions • See Salamanders and Lizards – Quiz M 3/3 • Chapter 9 – L-P population estimates • Due today: all of Prickly Pear Case Study • Exam postmortem due Wednesday!!

3. Class Amphibia • Order Anura – frogs and toads • Order Caudata – salamanders and newts • Order Apoda – caecilians Class Reptilia • Order Testudines - turtles, terrapins, and tortoises • Order Squamata - lizards and snakes • Order Crocodilia - crocodiles and alligators

4. Missouri Lizards and Salamanders All images are from Wikimedia Commons, unless otherwise identified

6. Common mudpuppyNecturusmaculosus

7. HellbenderCryptobranchusalleganiensis

8. Ringed salamanderAmbystomaannulatum

9. Tiger salamanderAmbystomatigrinum

10. Spotted SalamanderAmbystomamaculatum

11. Eastern newt, red-spotted newtNotophthalmusviridescens

12. Broad-headed skinkPlestiodonlaticeps

13. American five-lined skinkPlestiodonfasciatus

14. Little brown skinkScincellalateralis

15. Prairie lizard, eastern fence lizardSceloporusundulatus

16. Not on quizAxolotlAmbystomamexicanum

17. Chapter 9 – Population Distribution and Abundance • What are some methods of counting populations?

18. Chapter 9 – Population Distribution and Abundance • What are some methods of counting populations? • What if the individuals are mobile? • Hidden/“cryptic”? • What if we only have a sample?

19. Required variables • N = n1n2/m2 • N = estimated population size • n1 = number of individuals marked in first sample. • n2 = number of individuals marked in second sample. • m2 = number of individuals captured in second sample, that were marked in the first.

20. This method only works IF: • Probability of survival is equal • Births and deaths are insignificant between release and recapture • Immigration and emigration are nonexistent or insignificant • Marked individuals re-mix randomly • The mark makes it no easier or more difficult to recapture • Marks are permanent

21. Practice A biologist nets 45 largemouth bass from a farm pond, tags their fins, and releases them unharmed. A week later, she nets 58 bass from the pond, including 26 tagged. Based on the L-I index, estimate the size of the population.

22. Mark-Recapture • m2 / n1 = probability that an animal will be captured. • So, how large is the population? • n2 is really the portion of N that we expect to capture. • This is N*p = n2 where p is m2/n1.

23. Population Density • So, N*p = n2 • N = n2 / p • N = n2 / (m2 / n1) = n1n2 / m2 • But, this is only part of the problem. We also need some estimate of area since Density, D = N / A.

24. Population Density • Imagine we study rodents using a trapping grid w/ 15m trap spacing. • We trap the animals over a series of nights, always noting the identity and location of each animal. • Then, we can estimate how far each individual moved between captures.

25. Population Density • Now, if an organism can travel from one station to the next, we can assume that it could travel half the distance to the next station as well. • Thus, the ‘effective area’ of our sample is the area of our grid, plus a border region around the grid, with a width of half the distance between stations.

26. Population Density

27. Area? • What is the area of the grid? • Ag = W2 • How about the 4 rectangles? • Ab= 4 * W * (0.5 * D) • How about the 4 corners? • This is essentially the area of a circle. • Ac = (0.5D)2

28. Population Density • Finally, density can be estimated as