1. Succession and Stability (Ch. 20)

2. Community/Ecosystem “Stability” Stability: Absence change Resistance: Maintain structure/function in face of disturbance/stress Resilience: Speedy recovery

3. Desert Stream “Stability” Surface/subsurface waters: Sycamore Creek AZ. –Upwelling: from streambed to surface –Downwelling: opposite –Upwelling zones high nitrate

4. Desert Stream “Stability” Upwelling zones rapid recovery after flood (great resilience)

5. Desert Stream “Stability” Resistance: Maintain structure/function in face of disturbance. –Upwelling zones determined by bedrock –Not influenced floods: resistant to flood effects

6. Studying succession: repeat photography Recall chronosequence: sites vary in time since disturbance Can study succession same site: using repeat photography –Ex, MacDougal Crater, Mexico Volcanic crater 1 mile diameter

7. 1907 1959

8. 1972 1984

9. Changes: Fewer cresosote bushes, more saguaro

10. Photo points: being established in parks Enchanted Mesa, New Mexico. Juniper more common

11. Landscape Ecology Ch. 21

12. Landscapes Landscape Ecology: Study landscape structure & processes –Landscape: Heterogeneous area (several ecosystems) –Landscape Elements: Visually distinctive patches in ecosystem

13. Landscape Structure Ex: analysis Ohio landscapes –Compare Monroe vs. Somerset (most? How much more?)

14. Landscape Structure Ex: analysis Ohio landscapes –Compare Monroe vs. Somerset –Which of 6 has most forest cover?

15. Landscape Structure Patch no.? Size? Shape?

16. Landscape Structure Quantify patch shape: patch perimeter divided by perimeter circle w/area = patch S = P/2  (  A) –S = Patch shape Increasing value indicates less circular shape –P = Patch perimeter –A = Patch area

17. Landscape Structure Perimeter/area relations can matter….

18. Edge effect: altered habitat at fragment margin –Ex, forest patches--Major impacts: Increased % edge habitat (ecotone) Decreased distance edge to center –Effects differ on edge vs. interior species

19. Edge effects example Negative species interactions –Predators, nest parasites Who am I? Hint?

20. Edge effects Ex, brown-headed cowbird –Brood parasite: lays eggs nests >100 birds –Studies: parasitism increases fragmented forests Parasitized nest (2 cowbird eggs)

21. Fractal Geometry Describe mathematically complex shapes

22. Fractal Geometry Perimeter estimates depend on size measuring device. AK!

23. Fractal Geometry Ex, Admiralty Island, AK

24. Fractal Geometry Coastline length differs: eagles and oil molecules! Exxon Valdez: 2,000 km coast polluted (1989)

25. Landscape Processes Landscape processes: energy, materials, species move between ecosystems Metapopulations: Spatially isolated patches (significant exchange individuals)

26. Landscape Structure and Dispersal Ex: desert bighorn sheep

27. Landscape Structure and Dispersal Ex: desert bighorn sheep

28. Landscape Structure and Dispersal Ex: bighorn sheep Populations <50 extinct!

29. Landscape Structure and Dispersal Patch size affects movement Sherman live trap

30. Landscape Structure and Dispersal Results Peromyscus (deer mouse) Sigmodon (cotton rat) Small patches: animals move farther

31. Landscape Structure and Dispersal Fewer animals move in small patches (fragmentation leads to less moving) Microtus (vole)

32. Landscape Structure and Dispersal Butterfly density affected by patch size & isolation Melitaea cinxia Glanville fritillary Plantago lanceolata Larval food plant

33. Landscape Structure/Dispersal Pop. size increased with patch area (1) Pop. density decreased as area increased (2) 1 2

34. Landscape Structure/Dispersal Other conclusions….Isolated patches have low butterfly densities –Partially maintained by immigration –Small pops. likely go extinct!

35. Dispersal So, populations can be: 1) source populations: supply immigrants 2) sink populations: require immigrants to persist

36. Habitat corridors Connecting habitat –Corridors influence movement butterflies Common buckeye Variegated fritillary

37. Habitat corridors Corridors (large scale) Ex, Cascades….

38. Habitat corridors Corridors (small scale) Landscape bridge over highway in Germany

39. Landscape Position and Lake Chemistry Lake position affects responses to drought.

40. Landscape Position and Lake Chemistry Lower lake: level changed less Dissolved minerals changed more

41. Soil/Vegetation Mosaics Sonoran Desert Bajadas (sloping eroded materials @ base mountains) in Sonoran Desert

42. Soil/Vegetation Sonoran Desert Plant distributions: affected by soil age –Old soils with caliche and clay Caliche: Cemented carbonate layer

43. Soil/Vegetation Mosaics Sonoran Desert Soil structure Larrea: dominates old + young soils Ambrosia: dominates soils of intermediate age

44. Organisms & Landscape Structure Humans: conversion of forest to agricultural landscapes.

45. Humans Cadiz township, WI. Clearing for agriculture (fragmentation)

46. Humans Netherlands: forest increased as sheep raising ceased heathland US: sharecropping

47. Other Organisms and Landscape Structure African elephants & trees. –Change woodland to grassland.

48. Other Organisms and Landscape Structure Kangaroo Rat burrow systems Aerial photo Banner-tailed kangaroo rat

49. Other Organisms and Landscape Structure Alligator ponds (Everglades) Refuges: aquatic organisms during droughts

50. Other Organisms Beavers modified nearly all streams

51. Other Organisms Trapping (mostly fur) almost drove them extinct

52. Organisms Study: –Beavers changed boreal forest to mosaic.

53. Organisms Beavers (1927-1988) increased most ions and nutrients Last story….

54. Fire and Structure of a Mediterranean Landscape Chaparral (Mediterranean shrubland) in S. California. Burns periodically

55. Fire and Structure of a Mediterranean Landscape Fire suppression: Effect on fire size?

56. Fire and Structure of a Mediterranean Landscape Study: satellite photos Reconstruct fire history S. CA & N. Baja (1971-80). –Similar climates (little fire suppression N. Baja) 2007 smoke plumes

57. Fire and Structure of a Mediterranean Landscape Total area burned similar

58. Fire and Structure of a Mediterranean Landscape Small burns frequent in N. Baja, larger burns S. CA Fire suppression leads to larger fires (megafires: very large & destructive)!