CWS CFB Suffield SIRC

Transcription

1 Snake Road Mortality Study Suffield NWA Aug - Sep 2000 A Progress Report 19 Feb 2001 CWS CFB Suffield SIRC

2 Study Goal: To understand effects of traffic upon snake survival at Suffield National Wildlife Area and vicinity Study Objectives: Evaluate movements of snakes across roads at different orientation and distance from river, and by date and time of day Monitor movements of vehicles by location, date and time of day Monitor types of vehicles Compare movement and mortality of snakes with traffic patterns Compare mortality of snakes with past observations.

3 29 Road Survey Segments Suffield NWA CFB Suffield

4 Survey Approach: Systematic truck surveys of roads within southern portion NWA between Bingville Road to river, S. Boundary Trail to Interface also sampled Scott s s Road between Gate 24 and Bingville,, and Box Springs Road from Gate 24 to west turn segments in 6 routes of variable length, total of 205 routes surveyed total of 29 survey segments in study area, from 1.6 km to 6.4 km in length total of 2606 segments surveyed total of 10,038 km surveyed total of 36 survey days over 43 day period, from Aug 21 to Oct t surveys over 12 hours, within 4 3-hour 3 survey periods: survey speed about 50 kph

5 Study Approach,, continued each segment surveyed from minimum of 50 times (western segments) to over 120 times (most eastern segments) all vehicles recorded (type, size, speed, no. axles, if in convoy) live snakes captured, dead snakes preserved weather conditions monitored during all surveys

6 Percent of Total Segments Surveyed by Survey Period (n = 2606) Percent of Total Segments Surveyed n = 770 n = 667 Stop Surveys West of Sapper Trail n = 577 n = 420 Stop Surveys West of South Buffalo Road n = Aug 21 - Aug 28 Aug 29 - Sep 6 Sep 6 - Sep 15 Sep 15 - Sep 24 Sep 25 - Oct 2 Survey Period

7 Frequency of Survey of Road Segments 29 segments 2606 surveys y 100 No I J K L AA U S Q O M E F G H Z V T R P N CC BB A B C D Y X W Bingville Road N-S Bingville Road to Sapper Road E-W trails Sapper Road N-S Sapper Road to South Buffalo Road E-W trails South Buffalo and Box Springs Road N-S S. Buffalo Rd to River E-W Trails

8 Percent of 3 hr Survey Period Morning Segment A South Buffalo Road beween South Boundary Road and Porton Trail Percent of 3 hr Survey Period Segment A South Buffalo Morning 2 0 A21 A23 A25 A27 A29 A31 S2 S4 S6 S8 S10 S12 S14 S16 S18 S20 S22 S24 S26 S28 S30 Date

9 50 45 morning midday n =420 Percent of Segment Surveys in Survey Period n = 770 afternoon evening n =667 n = 577 n = 172 n = Aug 21 - Aug 28 Aug 29 - Sep 6 Sep 6 - Sep 15 Sep 15 - Sep 24 Sep 25 - Oct 2 Aug 21 - Oct 2 Survey Period Combined

10 Percent Percent of Total of Total Km Km > > Morning All 5 Survey Periods Midday All 5 Survey Periods Survey Survey Effort Effort by by Time Time Period of Day km surveyed 2911 km surveyed % Percent of Total of Total Km Surveyed km 2911 km surveyed 3301 km surveyed Afternoon Afternoon Evening km surveyed 1709 km surveyed 2117 km surveyed km surveyed

11 Average No. Vehicles Per 100 km Survey Morning 0 Midday 188 Morning 0 Midday km surveyed km surveyed > First 2 Survey Periods Afternoon Evening 141 Aug 21 - Sep Afternoon Evening Estimated Aver. No. of Vehicles km surveyed First 2 Survey Periods Combined 1709 km 1700 surveyed Per 100 km Aug of 21 Survey - Sep 6 68

12 800 Survey Period 1 Aug 21 - Aug 28 morning Estimated Number of Vehicles over 8 days of Survey 700 Bingville Rd 600 Estimated No Vehicles Sapper Trail S. Buffalo Rd I J K L AA U S Q O M E F G H Z V T R P N CC BB A B C D Y X W Segment

13 800 Survey Period 1 Aug 21 - Aug 28 evening Estimated Number of Vehicles over 8 days of Survey 700 Estimated No. of Vehicles Sapper Trail Box Springs S. Buffalo Rd 100 Bingville Rd 0 I J K L AA U S Q O M E F G H Z V T R P N CC BB A B C D Y X W Segment

14 All 5 Survey Periods Combined, On NWA 2% 5% 1% 1% 10% Sample Size % 58% 1/2 and 1 ton semi & tractor trailer tanker frac truck other > 1 ton grader or frontend loader car/motorcycle

15 Percent by Type, Survey Period 1, On NWA Sample Size 176 2% 2% 1%1% 11% Percent by Type, Survey Period 2, On NWA 5% 8% 0% 1% Sample Size 88 9% 53% 54% 30% Percent by Type, Survey Period 3, On NWA 0% Sample Size 67 0% 3%0% 13% 1/2 and 1 ton semi & tractor trailer tanker frac truck other > 1 ton grader or frontend loader car/motorcycle 23% Percent by Type, Survey Period 4, On NWA Sample Size 18 6% 0% 3% 22% 50% 0% 0% 81% 22%

16 Percent by Type, Morning, ON NWA Sample Size 139 2% 0% 6% 2% 12% Percent by Type, Midday, On NWA Sample Size 90 1% 0% 8% 1% 8% 53% 22% 60% 25% Percent by Type, Afternoon, On NWA 12% 0%1% 0%0% Sample Size 86 1/2 and 1 ton semi & tractor trailer tanker frac truck other > 1 ton grader or frontend loader car/motorcycle Percent by Type, Evening, In NWA 8% 8% 0% 0% 5% Sample Size 38 23% 13% 64% 66%

17 Percent of Vehicles > 1 ton Bingville Road Sapper Road South Buffalo Road South Boundary East South Boundary Trail Porton Trail Coyote Trail Dugway Trail Interface/Trum peter Trail Scott's Road Box Springs Road Vehicles greater than 1 ton Percent of Total Vehicles All Survey Periods Road Percent

18 Snake Encounters Suffield NWA fall 2000 Species Alive Dead Total % Dead Praire Rattlesnake Bullsnake Hognose Snake Wandering Garter Snake Plains Garter Snake Unknown Snake Total

19 Prairie Rattlesnake Aug-Sep 2001 alive dead

20 Bullsnake Aug-Sep 2001 alive dead

21 Plains Hognose Snake Aug-Sep 2001 alive dead

22 Wandering Garter Snake Aug-Sep 2001 alive dead

23 Plains Garter Snake Aug-Sep 2001 alive dead

24 After 20 August South Buffalo Road - S. Boundary to Interface Species alive dead total % dead alive dead total % dead alive dead total % dead Prairie Rattlesnake Bull Snake Plains Hognose Snake Wandering Garter Snake total Box Springs Road (Gate 24 to "S" turn) and Scott's Road (Gate 24 to Bingville Road) Species alive dead total % dead alive dead total % dead alive dead total % dead Prairie Rattlesnake Bull Snake Plains Hognose Snake Wandering Garter Snake total

25 survey effort was relatively systematic by location, date & time of day traffic levels were highly variable by location, date and time e of day about 50% of vehicles were half tons or one tons some vehicles > 1 ton appeared to have been moved west as planned very few snakes were observed in 2000 even with high survey efforte most snakes were observed on north/south roads as observed in previous years, and as expected snake numbers on South Buffalo in 2000 were similar to 1994 and1995 a even though survey effort was low in earlier years low sample sizes of snake observations, and highly variable traffict patterns, did not allow assessment of snake mortality in relation to traffic

26 Why so few snakes observed in 2000? chance? conditions? population size? Why traffic may be a problem? orientation of roads high traffic on roads near river pattern of snake movement westward considered problem in other areas some species vulnerable due to life history characteristics

27 Prairie Rattlesnake den 1 den 2 den 3 den 4 den 5 den 7 den sp95 fall95 sp96 sp97

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