1 / 54

Aimee C. Wyrick Division of Biological Sciences The University of Montana

Demography of the Columbia Spotted Frog ( Rana luteiventris ) in the Presence or Absence of Fish in the Absaroka-Beartooth Wilderness, Montana. Aimee C. Wyrick Division of Biological Sciences The University of Montana. Global Amphibian Decline. Threats to Amphibian Persistence.

claudia-morton
Download Presentation

Aimee C. Wyrick Division of Biological Sciences The University of Montana

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Demography of the Columbia Spotted Frog (Rana luteiventris) in the Presence or Absence of Fish in the Absaroka-Beartooth Wilderness, Montana Aimee C. Wyrick Division of Biological Sciences The University of Montana

  2. Global Amphibian Decline

  3. Threats to Amphibian Persistence • Habitat loss and fragmentation • Pesticides • Ultraviolet light • Infection from fungus and bacteria • Introduced species

  4. Introduced Species

  5. Muir Wilderness and the Mountain yellow-legged frog (Rana muscosa) http://www.conservationisconservative.org/muirwild.jpeg http://www.biologicaldiversity.org/swcbd/species/images/floatfrog2.jpg

  6. Lakes above 800 m From Bahls 1992

  7. Absaroka-Beartooth Wilderness and the Columbia Spotted Frog (Rana luteiventris)

  8. How do introduced fish affect Columbia spotted frogs? Do they coexist? • Larval biology and metamorphosis • Adult demography and reproductive biology Figure from Vonesh and De la Cruz 2002

  9. The Absaroka-Beartooth Wilderness

  10. Fish only Frogs only Fish and Frogs Neither

  11. Fish only Frogs only Fish and Frogs Pond Characteristics Area (ha) Conductivity (mS) Perimeter (m) Max depth (m) 746.7 14.3 2.5 8.4 178.4 10.3 0.2 1.4 230.0 16.5 0.3 3.4

  12. Water Temperature 7/12/2001 • Wide water temperature fluctuations Hourly 8 pm 4 am 8 am 4 pm 12 am 12 pm Time (hours) Daily

  13. Littoral vs. Deep Water 13-July and 28-July, 2001

  14. Precipitation(mostly as snowfall) • Annual precipitation was average in 1999 but less than average in 2000 and 2001. Data from Fisher Creek SNOTEL database – http://www.wcc.nrcs.usda.gov

  15. How do introduced fish affect Columbia spotted frogs? • Larval biology and metamorphosis Figure from Vonesh and De la Cruz 2002

  16. Growth = size at metamorphosis Resource allocation Development = larval period The Larval Stage and Predation Risk Resource Quality  Poor : Resource Availability  Low : Thermal Regime  Limited

  17. Low resource levels High resource levels Optimum Size at metamorphosis Physiological minimum Larval period The Larval Stage Wilbur and Collins 1973

  18. Low resource levels High resource levels Optimum Size at metamorphosis Physiological minimum Larval period The Larval Stage A shift in response to predation risk Wilbur and Collins 1973

  19. Expected effect of fish presence on larval biology and metamorphosis Slower larval growth rates Slower larval developmental rates Smaller metamorphs Fewer metamorphs Observed effect of fish presence on larval biology and metamorphosis Why? Risk of predation  poor resource conditions Risk of predation  poor resource conditions Metamorphs exit at minimum size to avoid further predation risk Because of poor resource conditions, fewer larvae survive to minimum size – direct predation

  20. How does the presence of fish affect CSF larval biology and metamorphosis? • Larval growth and development • Metamorph emergence and size

  21. Larval Growth and Development 50 and 51 are ponds with fish 49a and 49 are ponds without fish • Larval growth and developmental rates slower in ponds with fish

  22. * p < 0.05 * Number and Size of Metamorphs • 15 times more metamorphs emerged from ponds without fish • Larger metamorphs emerged from ponds without fish

  23. Expected effect of fish presence on larval biology and metamorphosis Slower larval growth rates Slower larval developmental rates Smaller metamorphs Fewer metamorphs Observed effect of fish presence on larval biology and metamorphosis Slower growth rates Why? Risk of predation  poor resource conditions Risk of predation  poor resource conditions Metamorphs exit at minimum size to avoid further predation risk Because of poor resource conditions, fewer larvae survive to minimum size – direct predation

  24. Expected effect of fish presence on larval biology and metamorphosis Slower larval growth rates Slower larval developmental rates Smaller metamorphs Fewer metamorphs Observed effect of fish presence on larval biology and metamorphosis Slower growth rates Slower developmental rates Why? Risk of predation  poor resource conditions Risk of predation  poor resource conditions Metamorphs exit at minimum size to avoid further predation risk Because of poor resource conditions, fewer larvae survive to minimum size – direct predation

  25. Expected effect of fish presence on larval biology and metamorphosis Slower larval growth rates Slower larval developmental rates Smaller metamorphs Fewer metamorphs Observed effect of fish presence on larval biology and metamorphosis Slower growth rates Slower developmental rates Smaller metamorphs Why? Risk of predation  poor resource conditions Risk of predation  poor resource conditions Metamorphs exit at minimum size to avoid further predation risk Because of poor resource conditions, fewer larvae survive to minimum size – direct predation

  26. Expected effect of fish presence on larval biology and metamorphosis Slower larval growth rates Slower larval developmental rates Smaller metamorphs Fewer metamorphs Observed effect of fish presence on larval biology and metamorphosis Slower growth rates Slower developmental rates Smaller metamorphs Fewer metamorphs Why? Risk of predation  poor resource conditions Risk of predation  poor resource conditions Metamorphs exit at minimum size to avoid further predation risk Because of poor resource conditions, fewer larvae survive to minimum size – direct predation

  27. How do introduced fish affect Columbia spotted frogs? • Adult demography and reproductive biology Figure from Vonesh and De la Cruz 2002

  28. Metamorph size Adult size Metamorph size Larval size Influence of larval stage on adult condition

  29. Influence of Adult Size • Predation risk Size Predation risk

  30. 4 years Size Sexual maturity Influence of Adult Size • Age at maturity 0 4 8 12 16 Age (years)

  31. Influence of Adult Size • Number and size of eggs Size Number and size of eggs

  32. Expected effect of fish presence on adult demography and reproductive biology Fewer adults and lower probability of survival Impact on adult size (larger) Earlier age at sexual maturity Greater investment in offspring (size of eggs and/or number of eggs) Observed effect of fish presence on adult demography and reproductive biology Why? Direct predation Larger frogs escape predation Optimize reproductive output Optimize reproductive output

  33. How does the presence of fish affect CSF adult demography and reproductive biology? • Capture-mark-recapture • Body size and weight • Skeletochronology • Reproductive investment Year 2

  34. No Fish Fish Stocked Self-sustaining Abundance ac • Distribution of adult frogs is related to fish permanence ns ac * p < 0.05 Fish Presence Fish Permanence

  35. Male Female 1990 1987 1996 1993 1992 1991 1989 1988 1998 1997 1995 1994 Age Distribution No Fish • Older frogs • High recruitment corresponds to low snowfall (longer growing season) Fish • Younger frogs

  36. Adult Survivorship * * p < 0.05

  37. Without Fish With Fish Adult Body Size Body length unrelated to fish presence Body weight is unrelated to fish presence

  38. Relationship Between Female Age and Size Without Fish With Fish R2 = 0.427, p < 0.05 R2 = -0.032, p > 0.05 • Females reach a larger size at a younger age in ponds with fish

  39. Relationship Between Male Age and Size Without Fish With Fish R2 = 0.005, p > 0.05 R2 = -0.038, p > 0.05 • No difference in relationship for male frogs

  40. Breeding Number of eggs/clutch • Non-significant but more eggs per clutch in ponds with fish n = 2 Total eggs laid • Almost 3 times total eggs laid in ponds with fish n = 7

  41. Expected effect of fish presence on adult demography and reproductive biology Fewer adults and lower probability of survival Impact on adult size (larger) Earlier age at sexual maturity Greater investment in offspring (size of eggs and/or number of eggs) Observed effect of fish presence on adult demography and reproductive biology Adults in ponds with low fish density, younger frogs, effect on survivorship unclear Why? Direct predation Larger frogs escape predation Optimize reproductive output Optimize reproductive output

  42. Expected effect of fish presence on adult demography and reproductive biology Fewer adults and lower probability of survival Impact on adult size (larger) Earlier age at sexual maturity Greater investment in offspring (size of eggs and/or number of eggs) Observed effect of fish presence on adult demography and reproductive biology Adults in ponds with low fish density, younger frogs, effect on survivorship unclear No clear influence on body size Why? Direct predation Larger frogs escape predation Optimize reproductive output Optimize reproductive output

  43. Expected effect of fish presence on adult demography and reproductive biology Fewer adults and lower probability of survival Impact on adult size (larger) Earlier age at sexual maturity Greater investment in offspring (size of eggs and/or number of eggs) Observed effect of fish presence on adult demography and reproductive biology Adults in ponds with low fish density, younger frogs, effect on survivorship unclear No clear influence on body size Females appear to reach maturity at a younger age Why? Direct predation Larger frogs escape predation Optimize reproductive output Optimize reproductive output

  44. Expected effect of fish presence on adult demography and reproductive biology Fewer adults and lower probability of survival Impact on adult size (larger) Earlier age at sexual maturity Greater investment in offspring (size of eggs and/or number of eggs) Observed effect of fish presence on adult demography and reproductive biology Adults in ponds with low fish density, younger frogs, effect on survivorship unclear No clear influence on body size Females appear to reach maturity at a younger age More eggs laid per clutch Why? Direct predation Larger frogs escape predation Optimize reproductive output Optimize reproductive output

  45. How do introduced fish affect Columbia spotted frogs? Figure from Vonesh and De la Cruz 2002

  46. How do introduced fish affect Columbia spotted frogs? Do they coexist? Figure from Vonesh and De la Cruz 2002

  47. Recruitment • Almost 50 times higher survival to metamorphosis in ponds without fish Estimated Survival Rate 22483 3137 14.0% No Fish 184 Fish 61718 0.30%

  48. How do introduced fish affect Columbia spotted frogs? Do they coexist?NObut they do co-occur

  49. In ponds with fish Number of offspring In ponds without fish Life span Age at maturity Why (or how) can they co-occur? • A life-history switch - maximizing reproductive output

  50. Fish only Frogs only Fish and Frogs Neither Why (or how) can they co-occur? • Numerous fish-free ponds and movement corridors SOURCE SINK

More Related