U.S. Geological Survey
April 4, 2002
|To:||Charles G. Groat, Director, U.S. Geological Survey|
|Through:||William K. Seitz, Deputy Regional Director for Alaska,
Wester Region U.S. Geological Survey /s/
|From:||Brad Griffith, Assistant Leader, Alaska Cooperative Fish and Wildlife Research Unit /s/|
|Subject:||Evaluation of additional potential development scenarios for the 1002 Area of the Arctic National Wildlife Refuge|
Figure 1. The five development scenarios (a-e) used by Griffith et. al (2002) for medeling June caribou calf survival as a function of annual calving ground displacement and the 2 additional scenarios (f,g) evaluated in this memo.
Griffith et al. (2002) used 5 published hypothetical development scenarios (Tussing and Haley 1999, Clough et al. 1987) (Figs. 1a-1e) to estimate the potential effect of oil development on calf survival during June for the Porcupine caribou herd. The estimate was based on an empirical model relating calf survival to both food available to lactating females and to the proportion of calves born in areas with low predation risk (Fig. 3.27 in Griffith et al. 2002). Observed concentrated calving areas for the Porcupine herd, 1985-2001, were displaced the minimum distance necessary to provide 4-km clearance from the roads depicted in Clough et al. (1987) (Fig. 1a) or the southern/eastern boundaries of the hypothetical development scenarios depicted in Tussing and Haley (1999) (Figs. 1b-1e). Associated annual calving grounds and calving sites moved accordingly, but only the concentrated calving grounds were required to have 4-km clearance. Calf survival before and after the hypothetical displacements was estimated with the empirical model generating a dataset of estimated changes in calf survival as a function of displacement distances (Fig. 3.28 in Griffith et al. 2002). The model predicted a reduction in calf survival as displacement distance increased. Average displacement increased as the scenarios progressed from limited development (Tussing and Haley 1999, scenario 2; Fig. 1b) to full development of the 1002 Area (Tussing and Haley 1999, scenario 5; Fig. 1e). The Clough et al. (1987) scenario was quite similar to the Tussing and Haley (1999) scenario 4 in its estimated effect on June calf survival. Variance of individual points about the estimated regression line (Fig. 3.28 in Griffith et al. 2002) resulted from variance in annual calving ground locations and variance in alternate habitats available each year. Average frequency of displacement, average displacement distance, and the predicted effects on June calf survival from the original model are presented in Table 1 for each hypothetical development scenario.
In this memo, we also report the results of evaluating 2 additional potential oil development scenarios (Figs. 1f-1g) using exactly the same modeling procedure presented by Griffith et al. (2002). These 2 additional development scenarios were derived from the most recent assessment of the distribution and abundance of petroleum resources in the 1002 Area (USGS 2001). Evaluation of those scenarios assumed that surface development would be restricted to either the Undeformed area (Fig. 1f) or to the Undeformed area plus Native lands (Fig. 1g) (USGS 2001).
Results for the 2 additional scenarios were similar to those obtained from Tussing and Haley (1999) scenarios 2 and 3 (Table 1). Average displacement distance for the 2 additional scenarios was estimated to be less than 5 km and the 95% confidence intervals on estimated change in June calf survival overlapped zero (Table 1). The position of the 2 additional scenarios in relation to the original model presented in Griffith et al. (2002) is shown in Figure 2.
Figure 2. Replication of Figure 3.28 from Griffith et al. (2002) to include the average displacement distance estimated from 2 additional hypothetical development scenarios (Undeformed area and Undeformed area + Native lands; USGS 2001). Vertical lines for each additional scenario intersect the estimated average change in calf survival and respective 95% confidence limits from the original Griffith et. al (2002) model.
|Tussing & Haley #2||17.6||1.7||-2.9||-0.7||1.4|
|Tussing & Haley #3||29.4||4.3||-3.1||-1.1||0.9|
|Undeformed area +
|Tussing & Haley #4||58.8||21.6||-5.2||-3.7||-2.2|
|Cough et al. (1987)||76.5||23.9||-5.5||-4.0||-2.6|
|Tussing & Haley #5||82.4||51.9||-9.6||-8.2||-6.7|
|Table 1. Estimated displacement frequency, average displacement distance, and change in June calf survival for the Porcupine caribou herd in relation to 7 hypothetical oil development scenarios. The entries in bold are the 5 scenarios incorporated in the original estimate of the change in June calf survival as a function of displacement distance (Griffith et al. 2002).|
Clough, N. K., P. C. Patton, and A. C. Christensen, editors. 1987. Arctic National Wildlife Refuge, Alaska, coastal plain resource assessment - report and recommendation to the Congress of the United States and final legislative environmental impact statement. U.S. Fish and Wildlife Service, U.S. Geological Survey, and Bureau of Land Management, Washington DC, USA.
Griffith, B., D. C. Douglas, N. E. Walsh, D. D. Young, T. R. McCabe, D. E. Russell, R. G. White, R. D. Cameron, and K. R. Whitten. 2002. The Porcupine caribou herd. Pages 8-37 in D. C. Douglas, P. E. Reynolds, and E. B. Rhode, editors. Arctic Refuge coastal plain terrestrial wildlife research summaries. U. S. Geological Survey, Biological Resources Division, Biological Science Report USGS/BRD/BSR-2002-0001.
Tussing, A. R., and S. Haley. 1999. Drainage pierces ANWR in Alaska study scenario. Oil and Gas Journal 97:71-84.
U.S. Geological Survey. 2001. Arctic National Wildlife Refuge, 1002 Area, petroleum assessment, 1998, including economic analysis. USGS Fact Sheet FS-028-01 (Supercedes FS-040-98) April 2001.