Previous research in the Milne Point oilfield in northern Alaska showed that the density of caribou (Rangifer tarandus) in the calving period within 1 km of a road was significantly lower after construction than before construction of the road. This was interpreted as displacement from the road and a functional loss of habitat and has been extensively cited as a documented effect of oilfield development on caribou. We continued this study with additional aerial surveys flown during 1991–2001 and compared caribou numbers and density in 6 1‐km intervals from the road over 3 time periods: pre‐road construction (1978–1981), early post‐road construction (1982–1987), and recent post‐road construction (1991–2001). During the recent post‐road period, the densities of calves and of all caribou were not significantly lower within 1 km of the road than the densities in the pre‐road period. In addition, calf density was higher in the interval within 1 km of the road than in the intervals 1–6 km from the road during the recent post‐road construction period. The total number of calving caribou observed in the study area has declined since pre‐road construction and early post‐road periods, but we found no evidence that caribou using the area during calving avoided areas near the road during the recent post‐road period. Numbers of caribou in the study area during the post‐calving period (after 20 June) during 1991–2001 were highly variable, but generally were higher than during calving. Analyses of relationships between calving and post‐calving caribou densities and distance intervals from Milne Point Road suggested that distributions of calves and adult caribou were not strongly influenced by presence of the road.

The purpose of this study was to design and test a monitoring protocol for marine waterfowl in the central Alaskan Beaufort Sea. The study provides an important case-study of how a long-term monitoring program may be affected by unanticipated human disturbances. Because of its overwhelming and widespread abundance, relatively sedentary behavior, ease in counting, and the extensive historical database, the long-tailed duck (Clangula hyemalis) was selected as the focal species. Two null hypotheses were formulated concerning potential changes in the numbers and distribution of long-tailed ducks in relation to disturbance in an industrial study area, compared to a reference study area located about 50 km to the east. A 9-year historical database (1977-1984, 1989) of long-tailed duck densities and other important data recorded during systematic aerial surveys was analyzed retrospectively using multiple regression techniques. The retrospective analyses determined which of several predictor variables recorded were significantly related to long-tailed duck density. Separate analyses were conducted for two periods: (1) the overall period when long-tailed ducks were present in the lagoon study areas, and (2) the shorter adult male molt period. The results of the two analyses indicated that 57% and 68%, respectively, of the total variation in long-tailed duck density during the two periods could be explained by variables recorded during the surveys. Predictor variables representing habitat, day of the year, time of day, amount of ice, and wave height recorded on-transect during surveys were most closely associated with long-tailed duck density. Measurement error during the surveys, and influences outside the study area such as nesting success in tundra habitats and mortality during migration and in over-wintering areas likely also had strong influences on the results, but these factors were not measurable in our study. Based on results of the retrospective analyses, a long-term monitoring protocol consisting of a program of systematic aerial surveys and an analyses of variance and covariance (ANOVA and ANCOVA) statistical procedure was designed and initially tested in 1990 and 1991. This 2-year testing phase resulted in several revisions to the monitoring protocol. Refinements were made to the original sampling procedures, to the survey schedule, and to the recommended statistical analysis procedures. Results of the ANOVA and ANCOVA indicated that there was no evidence of a change in long-tailed duck densities that could be attributable to disturbance (from any source) in the industrial study area relative to a reference area with no industrial development. Other analyses indicated that the sampling and analysis procedures would be adequate to detect long-term trends in long-tailed duck density and localized disturbance effects, but that the monitoring program should be continued well beyond two years to detect statistically significant changes. As a result, additional aerial surveys of both study areas were conducted again...

With increased use of toxicity testing for monitoring effluent toxicity, it is important to evaluate the precision of effluent toxicity tests To address this need, we identified, compiled, summarized, and evaluated published and unpublished data from intralaboratory and interlaboratory studies on the variability of acute and chronic effluent toxicity tests for single chemicals and effluents A total of 23 published and unpublished reports were identified The most extensive data on test variability are available for acute tests with Daphnia spp, Pimephales promelas, and Mysidopsis bahia and chronic tests with Pimephales promelas, Ceriodaphnia dubia, and Cyprinodon variegatus All other tests have considerably fewer data Data on which to evaluate the variability of toxicity tests produced by the most current U S Environmental Protection Agency methods are not extensive Mean C V s for intralaboratory studies (7‐33%) were smaller than those for interlaboratory studies (34‐46%) However, mean intra and interlaboratory C V s for chronic tests (7‐38%) were generally equal to or smaller than those from acute tests (17‐46%) Also, C V s from single chemical tests (32‐46%) were generally larger than those from effluent tests (7‐34%)

There is concern that caribou (Rangifer tarandus) may avoid roads and facilities (i.e., infrastructure) in the Prudhoe Bay oil field (PBOF) in northern Alaska, and that this avoidance can have negative effects on the animals. We quantified the relationship between caribou distribution and PBOF infrastructure during the post-calving period (mid-June to mid-August) with aerial surveys from 1990 to 1995. We conducted four to eight surveys per year with complete coverage of the PBOF. We identified active oil field infrastructure and used a geographic information system (GIS) to construct ten 1 km wide concentric intervals surrounding the infrastructure. We tested whether caribou distribution is related to distance from infrastructure with a chi-squared habitat utilization-availability analysis and log-linear regression. We considered bulls, calves, and total caribou of all sex/age classes separately. The habitat utilization-availability analysis indicated there was no consistent trend of attraction to or avoidance of infrastructure. Caribou frequently were more abundant than expected in the intervals close to infrastructure, and this trend was more pronounced for bulls and for total caribou of all sex/age classes than for calves. Log-linear regression (with Poisson error structure) of numbers of caribou and distance from infrastructure were also done, with and without combining data into the 1 km distance intervals. The analysis without intervals revealed no relationship between caribou distribution and distance from oil field infrastructure, or between caribou distribution and Julian date, year, or distance from the Beaufort Sea coast. The log-linear regression with caribou combined into distance intervals showed the density of bulls and total caribou of all sex/age classes declined with distance from infrastructure. Our results indicate that during the post-calving period: 1) caribou distribution is largely unrelated to distance from infrastructure; 2) caribou regularly use habitats in the PBOF; 3) caribou often occur close to infrastructure; and 4) caribou do not appear to avoid oil field infrastructure.