Geographic distribution, habitat association, and the importance of host quality for one of the rarest. (Mitoura thornei) Amy Lucas

Transcription

1 Geographic distribution, habitat association, and the importance of host quality for one of the rarest butterflies in North America: Thorne s hairstreak (Mitoura thornei) Amy Lucas University of Nevada, Reno Funding provided by SANDAG

2 Thank you

3 Thorne s Hairstreak (Mitoura thornei) Rare Recently discovered Bivoltine Larvae feed exclusively on H. forbesii (Tecate cypress)

4 Tecate cypress Serotinous Obligate seeder Fire intervals TH habitat Status

5 Stands of Tecate cypress

6 1984 listed 1995 Category abolished USFWS sued by various organizations 2012????? TH History

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9 Why study?

10 Project questions Where does TH live? What predicts where? Is tree age important?

11 Where does TH live?

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13 Random Points Exterior points placed Perimeter points placed randomly at least evenly every m outside from meters perimeter border Exterior Perimeter PP Interior points randomly placed at least 10 m inside from perimeter border

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15 Adult Thorne s hairstreak surveys Tap as many Tecate cypress branches and vegetation as possible in 5 m radius for 5 min 229 points surveyed 118 TH observed

16 Larval survey protocol Survey 8 Tecate cypress per point 129 points surveyed 38 larvae found

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21 TH found in 76% of stands Perc cent of stan nds Adults Larvae Adults or Larvae Adults and Larvae

22 0.205 % of points containing TH points Per rcent of Adults Larvae

23 Perimeter vs. Interior vs. Exterior: Exterior: 6% Perimeter: 48% Interior: 46% Adults

24 Perimeter vs. Interior: Larvae Perimeter: 55 % Interior: 45%

25 Project questions Where does TH live? What predicts where? Is tree age important?

26 Vegetation Sampling Protocol 360 points surveyed ed

27 Environmental Variables Tecate cypress DBH Tecate cypress density Woody richness Herbaceous richness Density of woody plants Herbaceous density Density of grasses Density of leaf litter, rock, and bare ground Slope of stands Distance between stands Size of stand

28 Levels of analysis Point Stand Larvae Presence/Absence Fractional presence Abundance Abundance Adults Presence/Absence Fractional presence Abundance Abundance

29 Point level analysis Larvae Presence/Absence Abundance Adult Presence/Absence Abundance

30 Levels of analysis Point Stand Larvae Presence/Absence Fractional presence Abundance Abundance Adults Presence/Absence Fractional presence Abundance Abundance

31 Stand-level analysis Larvae Fractional Seen Abundance Adult Fractional Seen Abundance

32 Statistical Methods Pairwise Mantel Response Variables Correlation Env Variables Multiple Mantel Env 1 Env 2 Distance Response Variable

33 Pairwise Mantel Results Larvae Adults Point Presence/Absence *TC DBH & Density, Distance b/w points Abundance *None Presence/Absence *TC DBH & Density, slope, Herb Density, Distance b/w points Abundance *None Stand Fractional presence *TC DBH Abundance *None Fractional presence *TC Cdensity Abundance *Size of stand, Woody richness

34 Multiple Mantel test results at the point level F Coefficient P R² Larvae P/A Whole model P TC DBH 3.45 e % Tecate 1.81 e Distance e

35 Multiple Mantel test results at the point level F Coefficient P R² Adults P/A Whole model P Slope 3.77 e Density of e herbaceous plants Density of 1.43 e H. forbesii

36 Project questions Where does TH live? What predicts where? Is tree age important?

37 Larval experiments

38 Methods Collected 86 larvae from 8 wild-caught M. thornei females Reared 56 larvae on foliage of three different ages of Tecate cypress

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40 Older trees not better P u p a l w e i g h t (mg)

41 Project questions Where does TH live? What predicts where? Is tree age important?

42 1984 listed 1995 Category abolished USFWS sued by various organizations 2012????? TH History

43 U.S. Fish and Wildlife Service Finds Thorne s Hairstreak Butterfly Does Not Warrant Protection Under the Endangered Species Act Lucas also recorded a new Thorne's hairstreak butterfly occurrence location in an area within the northwest quadrant of Otay Mountain in 2010, thus expanding the pre-2007 fire known range

44 The newly discovered observation location is over 1.5 miles (mi) (2 kilometers e (km)) from the nearest previous Thorne's hairstreak butterfly observation in the northeast quadrant

45 U.S. Fish and Wildlife Service Finds Thorne s Hairstreak Butterfly Does Not Warrant Protection Under the Endangered Species Act Surveys by Lucas on Otay Mountain in 2010 revealed the presence of Thorne's hairstreak butterfly throughout the majority of H. forbesii that burned in the 2003 fire, the 2007 fire, and in areas burned by both fires

46 Summary Thorne s hairstreak occurs more broadly than previously recognized Abiotic/biotic variables explain very little variation where Thorne s hairstreak is found Thorne s hairstreak utilizes perimeters Older trees are not better

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