THE PEBBLE ENVIRONMENT
Biological
Terrestrial Mammals A series of aerial surveys focused on the distribution and abundance of caribou, brown bears, black bears, moose, gray wolves and beaver dams in the Bristol
Many species of large mammals that inhabit southwest Alaska, while ecologically and economically important, are not particularly populous. Bay Drainages Study Areas, as well as on caribou and brown bears in the Cook Inlet Drainages Study Area. Observations of any of the other 40 or more species known or expected to occur in this area, such as red fox,
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river otters and other furbearers, were also recorded. Wildlife data was further enhanced with telemetry data on the Mulchatna Caribou Herd, ground visits to bear dens and incidental sighting by other scientists, pilots and project personnel. Many species of large mammals that inhabit southwest Alaska, while ecologically and economically important, are not particularly populous. The Bristol Bay Drainages Study Areas contained moderate densities of brown bears and low densities of black bears, moose, coyotes, wolves, river otters and wolverines. Specifically, the 2009 bear population survey conducted in collaboration with the Alaska Department of Fish and
THE MULCHATNA CARIBOU HERD Recognizing that the Mine Study Area is located within the historic range of the Mulchatna Caribou Herd (MCH), one of the larger herds in the state, scientists analyzed 29 years of radio-telemetry data from the Alaska Department of Fish and Game in order to understand population dynamics, seasonal patterns and changes in range use across several decades. Researchers then concluded, from telemetry data collected from 1981 through 2010, that the herd has declined dramatically in size since the mid-1990s. Use of the greater Mine Study Area by caribou from the MCH has varied considerably throughout the 29-year study period, with many different caribou using the area for at least a short period of time, with their principle range being located further west. During all 29 years, seasonal patterns indicate that large groups of caribou pass through the Mine Study Area in midsummer after calving elsewhere. There has been moderate to high-density use during spring, low-density use during calving, high-density use during summer and winter, and moderate-density use during autumn. A small resident herd of caribou was thought to be present during the early 1990s. Since the late 1990s, radio telemetry data and aerial transect surveys suggest the resident caribou no longer
occur in the area and that high-density use only occurs during the summer (post-calving) season. No habitats in the Mine Study Area were classified as high value for caribou. The Cook Inlet Drainages Study Area is almost completely out of the range of the MCH, and the steep coastal mountains and intertidal areas that dominate this area are not preferred caribou habitat. No caribou were observed during aerial transect surveys in the Cook Inlet Drainages Study Area in 2004 and 2005. In fact, in the 29 years of telemetry data analyzed, only one radio-collared caribou was found in the Cook Inlet Drainages Study Area.
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