1. Reproductive Biology of the Endangered Shrub, Fremontodendron californicum subsp. decumbens, and its Conservation Implications Robert Boyd Department of Biological Sciences Auburn University

2. 3 taxa recognized As species, or as subspecies of Fremontodendron californicum Note F. decumbens, only 1 site in Eldorado County, California

3. Fremontodendron californicum subsp. decumbens Found only near Pine Hill About 2,000 shrubs counted (<1mi radius) Listed as federally endangered in 1996 Pine Hill from SE

4. Closer view of Pine Hill chaparral F. californicum subsp. decumbens

5. Small shrub 1-2 meters tall F. californicum subsp. decumbens

6. Beautiful copper- colored flowers Fruit covered with stiff trichomes Seeds have orange appendage (elaiosome)

7. Basic Reproductive Biology Document reproductive attrition Mark flower buds Determine fates Marking flower buds in spring A bud marked with wire at its base

8. Basic Reproductive Biology Answer: insects attack flower buds, flowers, fruits Only 1.8% of flower buds survive to produce seeds

9. Basic Reproductive Biology Seed fates Predation: marked seeds (elaiosomes removed) in caged and uncaged locations under shrubs After 9 months extract and count surviving seeds Difference between caged/uncaged locations: rodent predation

10. Basic Reproductive Biology Seed fates: Predation Answer: 90% seeds eaten by rodents

11. Basic Reproductive Biology Seedling fates Most seeds dormant unless heat-treated Plant heat-treated seeds in caged and uncaged plots Document fates in each case

12. Basic Reproductive Biology Seedling fates Answer: Rodents eat some Insects eat most Rest die from drought during summer

13. Reproduction Model

14. Today’s story Pollination: insect visitors to flowers Dispersal: ants attracted to elaiosomes Focus on pollination and seed dispersal –Important life cycle stages –Involve mutualist animals

15. Today’s story Pollination: insect visitors to flowers Dispersal: ants attracted to elaiosomes Focus on pollination and seed dispersal –Important life cycle stages –Involve mutualist animals What roles of mutualists in reproduction of plant? What are conservation implications?

16. Focus on pollination Are insect visitors required to make fruits?

17. Focus on pollination Approach: enclose branches in bags to prevent insect visits Mark flowers already open with one color wire Mark large flower buds with another color

18. Focus on pollination Are insect visitors required to make fruits? Of 39 flower buds, 0% fruits Of 22 flowers open when bagged, 32% fruits

19. Focus on pollination Are insect visitors required to make fruits? Of 39 flower buds, 0% fruits Of 22 flowers open when bagged, 32% fruits Answer: Yes, visits required.

20. Focus on pollination What insects visit flowers? Which are likely pollinators?

21. Focus on pollination What insects visit flowers? Which are likely pollinators? Approach: watch flowers to document visitors During June of two years Document 1,746 insect visits.

22. Focus on pollination Tetralonia stretchii89.4% Callanthidium illustre8.7% Apis mellifera1% Other native bees2% Bee species Percent of visits Answer: Native solitary bees

23. Focus on pollination Dominant visitor: Tetralonia stretchii Stretching for nectar Gathering pollen Nectaries

24. Focus on pollination What insects visit flowers? Which are likely pollinators? Answer: Native solitary bees.

25. Focus on pollination How effective are bees? Approach: compare fruit set and seed set of hand-pollinated flowers.

26. Focus on pollination Fruit set not significantly different: –Hand-pollinated 80% Bee-pollinated 70%

27. Focus on pollination Fruit set not significantly different: –Hand-pollinated 80% Bee-pollinated 70% Seed set different: –Hand-pollinated: 4.9 seeds/flower –Bee-pollinated: 2.6 seeds/flower

28. Focus on pollination Fruit set not significantly different: –Hand-pollinated 80% Bee-pollinated 70% Seed set different: –Hand-pollinated: 4.9 seeds/flower –Bee-pollinated: 2.6 seeds/flower Answer: All flowers pollinated, pollen amount not maximized (seed set 53% of possible).

29. Focus on pollination How bees find flowers? Approach: UV photos

30. Focus on pollination How bees find flowers? Approach: UV photos UV lightAll light

31. Focus on pollination Summary : –Native solitary bees essential to seed production –Currently not maximizing seed set, but maximizing fruit set.

32. Focus on seed dispersal The ant connection –Harvester ant: Messor andrei –Attracted to elaiosomes of seeds

33. Focus on seed dispersal The ant connection –Carry seeds to nest –Remove elaiosome

34. Focus on seed dispersal The ant connection –Discard some intact seeds on midden (waste pile) around nest entrance –Nest entrances located in openings in chaparral

35. Focus on seed dispersal How do ants modify reproductive attrition? How does ant dispersal benefit plant?

36. Focus on seed dispersal Possibilities: –1) Do ants stimulate seed germination (scarify seeds)?

37. Focus on seed dispersal Possibilities: –1) Do ants stimulate seed germination (scarify seeds)? –2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas?

38. Focus on seed dispersal Possibilities: –1) Do ants stimulate seed germination (scarify seeds)? –2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas? –3) Do seedlings on ant middens have better chance survival?

39. Focus on seed dispersal Possibilities: –1) Do ants stimulate seed germination (scarify seeds)? –2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas? –3) Do seedlings on ant middens have better chance survival? –4) Do benefits occur after fire stimulates seed germination?

40. Focus on seed dispersal 1) Do ants stimulate seed germination (scarify seeds)? Compare germination of seeds –Fresh from fruits –Given to ants and recovered from midden.

41. Focus on seed dispersal 1) Do ants stimulate seed germination (scarify seeds)? –No statistical difference between fresh and ant- handled seeds 2.6%54% 5.4%66% Untreated seedsHeat-treated seeds Fresh seeds Ant-handled seeds % germination

42. Focus on seed dispersal 2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas?

43. Focus on seed dispersal 2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas? –Use seed trays placed in pairs –Place at canopy edge, 0.5 m, 1 m away in open

44. Focus on seed dispersal 2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas? –Use seed trays placed in pairs –Place at canopy edge, 0.5 m, 1 m away in open –Put seeds with elaiosomes in one tray, without in other of each pair –Compare seed removal.

45. Focus on seed dispersal –No effect of distance –More seeds with elaiosomes taken elaiosome no elaiosome

46. Focus on seed dispersal 2) Do ants protect seeds from rodent predation by moving them from under shrubs to open areas? –No, seeds not more safe in open –But removal of elaiosome helps seeds avoid rodent predation –This benefit of ant handling, but not benefit of elaiosome presence.

47. Focus on seed dispersal 3) Do seedlings on ant middens have better chance survival? –Plant heat-treated seeds on middens and under shrubs –Cage some to protect from rodents Ant middenUnder shrub canopy

48. Focus on seed dispersal Results: Mean seedling longevity in days (SD) 27 (23)46 (30) 17 (20)34 (27) Ant midden Canopy Caged Uncaged Caging helps, survival on middens is less!

49. Focus on seed dispersal 4) Do benefits occur after fire stimulates seed germination? Approach: experimental burn!

50. Focus on seed dispersal 4) Do benefits occur after fire stimulates seed germination? Takes lots of preparation/planning!

51. Focus on seed dispersal 4) Do benefits occur after fire stimulates seed germination?

52. Focus on seed dispersal 4) Do benefits occur after fire stimulates seed germination? Aerial viewGround view

53. Focus on seed dispersal Seedlings counted and marked during winter (rainy) season following fire Most under or at canopy edge

54. Focus on seed dispersal Survival higher for those dispersed away from canopy

55. Focus on seed dispersal Why? 1) Rodent predation greater under shrub canopy

56. Focus on seed dispersal Why? 2) Dispersed seedlings more likely to be near opening created by death of shrub Many chaparral shrubs re-sprout after fire, including Fremontodendron Resprouting Fremontodendron

57. Focus on seed dispersal Measure distance from each seedling to nearest: –Re-sprouting shrub –Dead shrub Those nearer to dead than live: considered to be close to opening in community

58. Focus on seed dispersal Measure distance from each seedling to nearest: –Re-sprouting shrub –Dead shrub Those nearer to dead than live: considered to be close to opening in community Near to dead: not same as “mostly dead”…..

59. Focus on seed dispersal Dead chamise shrub Fremontodendron seedlings

60. Focus on seed dispersal Summary of dispersal benefits (after fire): –1) Less rodent predation –2) Greater chance of being near opening in chaparral community.

61. Conservation Implications Pine Hill Reserve is small (97 hectares) Surrounding area being developed Cleared area west of Pine Hill

62. Conservation Implications Pollination –Native bees are required –These native bees are generalists

63. Conservation Implications Dangers –How big a reserve is needed to protect the bees? –Neighborhood activities may threaten bees Insecticide use off of Reserve could harm bees Plantings could draw bees away from the Reserve Solution: monitor pollination success

64. Conservation Implications Seed dispersal –Native ants are required –Benefits accrue only after fire

65. Conservation Implications Seed dispersal –Native ants are required –Benefits accrue only after fire Dangers –How big a reserve is needed to protect the ants? –How might land use in neighborhood affect ant populations? Land clearing, insecticide use, etc.

66. Conservation Implications Seed dispersal –Native ants are required –Benefits accrue only after fire Dangers –How big a reserve is needed to protect the ants? –How might land use in neighborhood affect ant populations? Land clearing, insecticide use, etc. Need to consider these questions, plan for periodic fire to stimulate germination.

67. Final lessons for endangered species management 1) Mutualist organisms important Most rare plants don’t have pollinators/dispersers identified

68. Final lessons for endangered species management 1) Mutualist organisms important 2) Habitat protection best way to maintain the web of life

69. Final lessons for endangered species management 1) Mutualist organisms important 2) Habitat protection best way to maintain the web of life 3) Managers must integrate biology with human needs/habitat uses

70. Final lessons for endangered species management