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Changes in the breeding distribution of Buff-breasted Flycatchers in the southwestern United States: the role of fire suppression. Chris Kirkpatrick & Courtney J. Conway USGS Arizona Cooperative Fish and Wildlife Research Unit, University of Arizona. Pablo Leautaud. Thanks to:.
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Changes in the breeding distribution of Buff-breasted Flycatchers in the southwestern United States: the role of fire suppression. Chris Kirkpatrick & Courtney J. Conway USGS Arizona Cooperative Fish and Wildlife Research Unit, University of Arizona
Thanks to: Field Assistants: Dominic LaRoche, Mike Schroff, Eli Rose, Kelly Bergstram, Brian Powell, and Mark Zepp Logistical Support: Natasha Kline, Don Swann (Saguaro National Park), Josh Taiz (U.S. Forest Service), Bob Peterson (University of Arizona), Shelly Danzer, and Sheridan Stone (U.S. Department of Defense) Bird Photography: Bruce Taubert and Tom Grey
Arizona New Mexico from Bowers & Dunning (1994)
91% reduction in U.S. breeding range from Conway and Kirkpatrick 2007
15% reduction in total breeding range Arizona New Mexico from Bowers & Dunning (1994)
What is current population trajectory? 9 highest sky island mtn ranges
71 surveys in Huachucas & Chiricahuas ARIZONA NEW MEXICO • TUCSON MEXICO
44 surveys in 7 adjacent mt. ranges • Replicated 1980-83 & 1995-96 surveys ARIZONA NEW MEXICO • TUCSON MEXICO
Point-count surveys • At 200 m intervals along • each survey route • From April to July • 3-min. passive period • 3-min. broadcast period
Regress year vs # BBFLs for 23 routes • Test Ho: average slope 0 # BBFLs Detected
BBFLs have declined on 16 of 23 routes bavg = -0.105 P = 0.061 # BBFLs Detected
BBFLs have declined on 16 of 23 routes bavg = -0.105 P = 0.061 Carr Canyon # BBFLs Detected
What’s happened to BBFLs in the U.S.? Fire suppression implicated…
Coniferous forests in the SW historically subjected to low-severity fires ~1x/decade From Swetnam and Betancourt 2003
1909 1949 1992 From Covington and Moore 1994
Increase in understory fuel loads has contributed to recent increase in frequency of wildfires in Southwest “Recent” Fires from Swetnam and Betancourt 2003
If observed declines in BBFLs are due to decreased fire frequency, then…. • 1) Recently burned forests more likely to be colonized by BBFLs • 2) Survey points with BBFLs more likely to have evidence of recent fires • 3) Survey points with BBFLs more likely to have evidence of more frequent fire events
If observed declines in BBFLs are due to decreased fire frequency, then…. • 1) Recently burned forests more likely to be colonized by BBFLs • 2) Survey points with BBFLs more likely to have evidence of recent fires • 3) Survey points with BBFLs more likely to have evidence of more frequent fire events
no BBFLs detected 5 recently burned survey routes 1 pair of BBFLs detected 5 unburned survey routes
Potential Problems: • Severity of fires was low • Sample size of survey routes was small
If observed declines in BBFLs are due to decreased fire frequency, then…. 1) Recently burned forests more likely to be colonized by BBFLs 2) Survey points with BBFLs more likely to have evidence of recent fires 3) Survey points with BBFLs more likely to have evidence of more frequent fire events
Burn Severity Index (5 classes): 0 1 2 3 4 • 0) no evidence of fire • low-severity surface fire • moderate-severity surface fire • high-severity surface fire • high-severity crown fire • Modified from Ryan & Noste 1985
Buff-breasted flycatchers more common in burned woodlands Burn Severity Class
Percent cover of vegetation at 4 heights differed among 5 burn-severity classes Burn-severity Class
Potential Problem: 1) Burn-severity index provides information on severity but not frequency of previous fire events
If observed declines in BBFLs are due to decreased fire frequency, then…. 1) Recently burned forests more likely to be colonized by BBFLs 2) Survey points with BBFLs more likely to have evidence of recent fires 3) Survey points with BBFLs more likely to have evidence of more frequent fire events
1916 Fire 14 survey routes without BBFLs 14 survey routes with BBFLs 1865 Fire 1842 Fire
Routes with BBFLs had more frequent fires tpaired = 1.8 P = 0.048 with BBFLs without BBFLs
Potential Problems: 1) not all trees scar during a fire 2) don’t know the severity of previous fires
Summary of results Fire frequency Fire severity
Why didn’t BBFLs colonize our 5 recently (<10 yrs) burned survey routes? 1) recruitment and immigration insufficient? 2) low-severity burns insufficient? 3) BBFLs may require >10 years to locate and colonize burns
Why didn’t BBFLs colonize our 5 recently (<10 yrs) burned survey routes? 1) recruitment and immigration insufficient? 2) low-severity burns insufficient? 3) BBFLs colonize areas >10 yrs post-burn?
Conducted surveys in 7 mt. ranges • adjacent to Huachucas & Chiricahuas Last BBFL recorded 18 Aug. 1911 We detected: 2 in 2000 4 in 2004 5 (incl. pair) in 2005 MEXICO
What’s driving BBFLs to re-colonize the Rincon Mountains after 89 year absence? Tucson Mica Mt 70% of bird survey points burned (56% burned severely) Ignitions and Fire History, Rincon Mountains, Saguaro National Park Ignition Points Rincon Peak Burn Perimeters
Carr Canyon <1976 4 1976 Fire 1983 9 1995 17 2004 23
Santa Catalina Mountains Bullock Wildfire (2002) & Aspen Wildfire (2003)
Santa Catalina Mountains >90% burned Variation in burn severity
Future work • Continue monitoring BBFL populations in Arizona (and New Mexico?) • Determine reproductive success to assess quality of habitat • Determine status of Mexican population
For more information: Conway, C. J., and C. Kirkpatrick. 2007. Effect of forest fire suppression on buff-breasted flycatchers. Journal of Wildlife Management 71:445-457. Kirkpatrick, C., C. J. Conway, and D. LaRoche. 2007. Range expansion of the Buff-breasted Flycatcher (Empidonax fulvifrons) into the Rincon Mountains, Arizona. Southwestern Naturalist 52: 149-152. Kirkpatrick, C., C. J. Conway, and P. B. Jones. 2006. Distribution and relative abundance of forest birds in relation to burn severity in southeastern Arizona. Journal of Wildlife Management 70:1005-1012.
For more information: www.ag.arizona.edu/srnr/research/ coop/azfwru/cjc/ • click on links to “Research” and “Past Project #8” and “Past Project #9” kirkpatr@email.arizona.edu