Central Arctic Caribou and Petroleum Development: Distributional, Nutritional, and Reproductive Implications

Abstract

We synthesize findings from cooperative research on effects of petroleum development on caribou (Rangifer tarandus granti) of the Central Arctic Herd (CAH). The CAH increased from about 6000 animals in 1978 to 23 000 in 1992, declined to 18 000 by 1995, and again increased to 27 000 by 2000. Net calf production was consistent with changes in herd size. In the Kuparuk Development Area (KDA), west of Prudhoe Bay, abundance of calving caribou was less than expected within 4 km of roads and declined exponentially with road density. With increasing infrastructure, high-density calving shifted from the KDA to inland areas with lower forage biomass. During July and early August, caribou were relatively unsuccessful in crossing road/pipeline corridors in the KDA, particularly when in large, insect-harassed aggregations; and both abundance and movements of females were lower in the oil field complex at Prudhoe Bay than in other areas along the Arctic coast. Female caribou exposed to petroleum development west of the Sagavanirktok River may have consumed less forage during the calving period and experienced lower energy balance during the midsummer insect season than those under disturbance-free conditions east of the river. The probable consequences were poorer body condition at breeding and lower parturition rates for western females than for eastern females (e.g., 1988-94: 64% vs. 83% parturient, respectively; p = 0.003), which depressed the productivity of the herd. Assessments of cumulative effects of petroleum development on caribou must incorporate the complex interactions with a variable natural environment.

Distribution and Movements of the Teshekpuk Caribou Herd 1990–2005: Prior to Oil and Gas Development

“…The seasonal ranges that caribou choose have life history consequences that are strongly influenced by their nutritional environment (Russell et al, 1993;Griffith et al, 2002;Cameron et al, 2005). Caribou maximize their nutritional intake through large-scale migratory movements to areas of higher habitat quality, changes in seasonal and annual distribution in response to changes in plant phenology and availability, and rapid movements to limit harassment by the mosquito (Culex spp.)…”

“…Interpretations of data collected to monitor the impacts on caribou of oil and gas development have been divergent (Cameron et al, 1992;Ballard et al, 2000;Cronin et al, 2000). During the 1980s, CAH calving occurred to the southwest, away from areas of development (Wolfe, 2000;Cameron et al, 2005). Much research throughout this period focused on negative multiplier effects (White, 1983) on the population resulting from the displacement of parturient cows to habitats that may be of lower nutritional quality than areas previously used by CAH cow-calf pairs (Wolfe, 2000;Cameron et al, 2005).…”

“…During the 1980s, CAH calving occurred to the southwest, away from areas of development (Wolfe, 2000;Cameron et al, 2005). Much research throughout this period focused on negative multiplier effects (White, 1983) on the population resulting from the displacement of parturient cows to habitats that may be of lower nutritional quality than areas previously used by CAH cow-calf pairs (Wolfe, 2000;Cameron et al, 2005). Cronin et al (2000) point out that the CAH population increased concurrently with oil and gas development and conclude that no population-level impacts from resource development have occurred.…”

A conceptual model for migratory tundra caribou to explain and predict why shifts in spatial fidelity of breeding cows to their calving grounds are infrequent

“…We acknowledge that other reasons, including weather and industrial development, can influence both individual cows (Carroll et al, 2005) and calving ground locations (Cameron et al, 2005). A variation in spatial fidelity, which is not the focus of this paper, is the effect of unusual weather during pre-calving migration.…”

Irruptive dynamics of introduced caribou on Adak Island, Alaska: an evaluation of Riney‐Caughley model predictions

“…While consistent inter-annual use of calving areas has been documented for a number of mainland herds with varying densities over time (Skoog 1968, Gunn andMiller 1986), shifts to a new calving area have occurred for some mainland herds in association with increasing population size (Taillon et al 2012), interchange of individuals between herds (Hinkes et al 2005), and anthropogenic disturbance (Wolfe et al 2000, Cameron et al 2005. Island caribou, however, inhabit a unique environment free from predation pressure, inter-specific competition, and new gene flow.…”