Wally Erickson Western EcoSystems Technology, Inc. Cheyenne, Wyoming Ed Arnett Bat Conservation International Austin Texas

Transcription

1 WIND-WILDLIFE INTERACTION: WHAT WE KNOW Wally Erickson Western EcoSystems Technology, Inc. Cheyenne, Wyoming Ed Arnett Bat Conservation International Austin Texas

2 Where did the avian concern start? Altamont Pass 1980s : turbines (now ~5000) of various designs in 60 sq. mile area. Arid rolling hills environment with high prey base (ground squirrels) and high raptor use. High raptor mortality golden eagles red-tailed hawks American kestrels burrowing owls Also other birds but historic study focus has been on raptors.

3 Bat Fatalities have been reported at all wind farms investigated in the U.S. across a wide range of habitats Prior to 2003 there was little concern over bat impacts at wind projects Buffalo Mtn, TN monitored only a 3 turbine wind project; reported 120 bats over a 3 year period Mountaineer, WV and Meyersdale, PA 132 bats in a 3 day period in 2003; 633 bats over a 6 week study Since then high numbers have also been reported at Maple Ridge, NY; Summerview, Alberta; Casselman, PA, Judith Gap, MT The guano had hit the fan P. Cryan, USGS Fort Collins Science Center

4 What are the Wind-Wildlife Issues? Avian Mortality Loss of Habitat Direct loss to facility Indirect loss to disturbance Bat Mortality T&E Species Issues

5 Avian Mortality Wind turbine collisions Met tower collisions Powerline collisions and/or electrocutions Vehicle collisions

6 High Winds, CA Altamont, CANWTC, CO Diablo Winds, CA Montezuma Hills, CA UD, CA Tehachapi Pass, CA San Gorgonio, CA Fatality Monitoring Studies Bighorn WA Wildhorse WA Hopkins Ridge, WA Judith Gap, MT Combine Hills, OR NPPD Ainsworth, NE Condon, OR OK WEC, OK Buffalo Gap, TX Red Canyon, TX New Project since NWCC 2001 Summary Top of Iowa Algona Iowa Data reported in NWCC 2001 Summary Additional data collected since NWCC 2001 Summary Mars Hill, ME Searsburg, VT Maple Ridge, NY Meyersdale, PA Somerset, PA WEST, Inc.

7

8 Composition of Avian Fatalities Songbirds 75% mixture of resident and likely nocturnal migrants No large mortality events Upland Gamebirds 10% introduced species primarily in Pac-NW Many or most unlikely turbine kills Raptors - <5% American kestrels, red-tailed hawks, occasionally other species Waterfowl - <5% generally low numbers relative to amount of use Others - <5% ravens and turkey vultures often high use but low mortality

9 Projected Mortality (Projects >600 kw turbines) All birds: 60, ,000 3/MW/yr +- ~1 bird/mw/yr Raptors: (excludes Altamont) 0.085/MW/yr Based on 20,000 MW Assumption: studies are unbiased and studies are like a random sample of wind projects

10 Pre-Construction Objectives Predict Impacts: Quantify level of use and species composition of birds in project area to compare to other projects for the purpose of predicting impacts Siting: Identify areas of project or relations with habitat to micro-site turbines

11 Raptor Use Raptor Fatality If line was not there, what would be your prediction? Range: /MW/yr WEST, Inc.

12 Buffers from Nest Sites Avoid Saddles Avoid Windward Side of Ridges

13 Research Studies - Lighting Data to date suggests no measured increase in bird or bat mortality due to lighting on turbines blinking red or white. Studies at Stateline, WA/OR; Mountaineer, WV; Combine Hills, OR; Hopkins Ridge, WA; Maple Ridge, NY Consistent with recent Communication Tower Results by Gehring et al. (2008)

14 Met Towers Four times higher mortality at guyed met towers compared to turbines at Foote Creek Rim - 5 guyed towers; 69 turbines Gehring 2008 guyed comm. Tower 10 times higher mortality than unguyed towers

15 Avian Mortality Summary Individual projects not impacting populations Siting very Important Impacts to Nocturnal Migrating Songbirds has generally been low Cumulative Impacts concern as Industry continues to expand

16 What are the Wind-Wildlife Issues? Avian Mortality Loss of Habitat Direct loss to facility Indirect loss to disturbance Bat Mortality T&E Species Issues

17 Sources of Habitat Impact Direct loss of habitat Turbine pads, roads, substations, transmission lines Indirect loss of habitat From behavioral response to wind project facilities Turbines, transmission lines, roads, human activity WEST, Inc.

18 Fragmentation/Displacement Impacts Indirect Habitat Loss Grassland songbird species Several wind turbine studies Prairie grouse Few wind turbine studies to date Some on-going NWCC sponsored KS, Texas Parks and Wildlife Anecdotal information and surrogate studies Raptors A few wind turbine studies Big game One study of elk, generally anecdotal otherwise

19 Monitoring Studies Disturbance Grassland Songbird Displacement Studies conducted at Buffalo Ridge, MN Small scale displacement (~ m) Ongoing studies of bird displacement at Stateline, Combine Hills (WA/OR) South Dakota: Preliminary data suggested some reduced densities for some species, no effect for others (Schaffer and Johnson 2008) Long-term Mountain Plover study Foote Creek Rim, WY suggests habituation; decline in numbers during construction; increase post construction

20 Big Game Species Displacement? Study at Foote Creek Rim of pronghorn; however, use was low pre-project limiting ability to detect effects. Blue Canyon OK no apparent effect on elk Wildhorse no indication elk avoid the wind project Oil and Gas studies (WEST 2008) suggest impacts to mule deer

21 What are the Wind-Wildlife Issues? Avian Mortality Loss of Habitat Direct loss to facility Indirect loss to disturbance Bat Mortality T&E Species Issues

22 Bat fatalities at wind farms have been documented worldwide U.S., Canada, Germany, Sweden, Spain, Australia Bat Fatalities have been reported at all wind farms investigated in the U.S. across a wide range of habitats Predicting Bat Fatalities at proposed wind projects focus of research

23 Five key unifying patterns of bat fatalities at wind facilities documented from studies in North America: (from Arnett et al. 2008) Fatalities are heavily skewed toward migratory bats, dominated by lasiurine species in most studies TO DATE; Studies consistently report peak turbine collision fatalities in midsummer through fall from all studies in North America; Fatalities are not concentrated at individual turbines (i.e., fatalities are distributed among turbines at facilities) and current studies have not yet identified consistent relationships with habitat variables (e.g., distance to water); Red-strobe lights recommended by the FAA do not influence bat fatality; and Bat fatalities are highest during periods of low wind speed and appear related to climate variables associated with the passage of weather fronts.

24 Regional Bat Fatalities Bat fatalities have been documented at wind facilities worldwide across a wide range of habitats appear to be highest at sites on forested ridges in eastern U.S (~28 bats/mw) possibly tens of thousands Recent studies have found higher than expected bat fatalities in open prairie in Alberta (~11/MW) Mixed agriculture/forest habitats in New York (~15/MW)

25 Patterns of Bat Fatality Thirteen of the 45 species north of Mexico have been found killed by turbines Hoary Bat Fatalities are skewed to migratory, tree roosting bats at sites currently studied BUT High proportions of Mexican free-tailed bats found at what few sites studied in the range of this species Mexican free-tailed bat

26 Patterns of Bat Fatality Hoary bats Fatalities highest in mid-summerfall, coinciding with migration of some species Timing of Bat Mortality Some evidence to suggest regional patterns in timing of fatality perhaps related to migration, weather or food Fatality Index meyersdale mountaineer Study Day

27 Lower Wind = Higher Bat Fatality Majority of bats killed in PA, TN, WV were on low wind nights; kills negatively related to wind speed Bat kills also associated with passage of weather fronts Patterns may be predictable!

28 MITIGATING BAT FATALITIES Proper Siting! Avoid building in high risk areas Operational Mitigation Curtailment during high risk periods that may be predictable Deter or alert the bats

29 Curtailment Studies: Recent study in Pennsylvania demonstrated an average reduction of kills of 82% (56-92%) with 5.0 and 6.5 m/s cut-in Study conducted in Germany found ~50% reduction of bat kills when turbine cut-in speed was changed to 5.5 m/s Study conducted in Alberta Canada showed a 52% reduction in kills with 5.5 m/s cut-in

30 No strong linkage between pre- construction assessments and post- construction fatality

31 Can indices of activity gathered pre- construction with acoustic detectors predict bat fatality post-construction?

32 Patterns of bat activity from pre-construction acoustic studies (from Arnett et al. 2006, 2007, Redell et al. 2006, Reynolds 2006) Temporal (nightly, monthly, annually) and spatial (vertical height and sampling stations) variation in acoustic data is extremely high Studies consistently report peak activity in mid-summer through fall, coinciding with migration and turbine kills Wind Speed: peak activity at low wind speed: most activity (up to 90%) occurs below 6 m/s high percentage of activity occurs below 4 m/s Ambient Temperature: most bat activity occurs on warmer nights during migratory season may relate to insect activity or thermoenergetic constraints

33 Can we generate a disorienting or uncomfortable airspace around turbines that will deter bats?

34 Current Findings In the lab: captive bats unable to catch prey with device on At ponds in the field: ~90% reduction within 12m of device Sustained effect at ponds, i.e., no indication of habituation Field experiment showed mixed results

35 CAUTION!!! We currently DO NOT have a functional device that can be deployed at operating wind facilities More field experimentation is required

36 What are the Wind-Wildlife Issues? Avian Mortality Loss of Habitat Direct loss to facility Indirect loss to disturbance Bat Mortality T&E Species Issues

37 Impacts to T&E Species No reported bald eagles to date but recently de-listed. No Indiana bats, grey bats, Virginia long-eared bats found to date. Rising concerns as numbers and locations of wind projects increase. e.g. Indiana bats in east, whooping crane migration corridor through midwest, blackcapped vireo in Texas Varied potential for impacts to listed terrestrial species; often a site specific concern