Observations on a Cyclic Decline of Lemmings (Lemmus) on the Arctic Coast of Alaska during the Spring of 1949

The importance to the biotic community of various species of lemmings in arctic and subarctic regions has long been recognized, but there is little known about the ecology of these mammals. of the two species that occur on the Arctic Slope of Alaska, namely, the collared lemming, Dicrostonyx groenlandicus rubricatus (Richardson), and the brown lemming, Lemmus trimucronatus alascensis Merriam, during the spring of 1949 the writer had the good fortune to observe a cyclic decline in the population of the brown lemming on the Arctic Coast of Alaska. Observations were made during the peak density preceding this decline and were continued for more than a year subsequent to it. It is the purpose of this paper to present the results of these studies.

Crop, Native Vegetation, and Biofuels: Response of White- Tailed Deer to Changing Management Priorities

The expansion of the cellulosic biofuels industry throughout the United States has broad-scale implications for wildlife management on public and private lands. Knowledge is limited on the effects of reverting agriculture to native grass, and vice versa, on size of home range and habitat use of white-tailed deer (Odocoileus virginianus). We followed 68 radio-collared female deer from 1991 through 2004 that were residents of DeSoto National Wildlife Refuge (DNWR) in eastern Nebraska, USA. The refuge was undergoing conversion of vegetation out of row-crop agriculture and into native grass, forest, and emergent aquatic vegetation. Habitat in DNWR consisted of 30% crop in 1991 but removing crops to establish native grass and wetland habitat at DNWR resulted in a 44% reduction in crops by 2004. A decrease in the amount of crops on DNWR contributed to a decline in mean size of annual home range from 400 ha in 1991 to 200 ha in 2005 but percentage of crops in home ranges increased from 21% to 29%. Mean overlap for individuals was 77% between consecutive annual home ranges across 8 years, regardless of crop availability. Conversion of crop to native habitat will not likely result in home range abandonment but may impact disease transmission by increasing rates of contact between deer social groups that occupy adjacent areas. Future research on condition indices or changes in population parameters (e.g., recruitment) could be incorporated into the study design to assess impacts of habitat conversion for biofuel production.

Monitoring Raccoon Rabies in Alabama: The Potential Effects of Habitat and Demographics

Density, morphometrics, and disease prevalence of raccoon populations were determined in 4 habitats (agriculture, riverine, managed, and forested) in central Alabama. In addition we monitored 71 collared raccoons to determine survival. Density estimates were similar in the agriculture (ag) and riverine habitats in central Alabama with 8 raccoons/km2, and lower in the forested habitat at 5 raccoons/ km2. Retention of juveniles did not appear to contribute to observed higher populations in the riverine and ag habitat. Although the riverine and ag, possibly due to supplemental resources, likely provide better habitat for raccoons, we found only body size in female raccoons to be different across habitats (P = 0.001). Human-caused mortality (either hunting or missing and presumed killed) was the main cause of mortality in several raccoon populations during fall; however, fall survival did not differ between the habitats (χ = 1.47, d.f. = 3, P = 0.69). Although rabies and distemper virus were prevalent in all habitats, they did not appear to contribute to mortality even with a high proportion of the population exhibiting positive CDV titers (ag – 44%, managed- 50%) and rabies titers (managed- 57% and riverine habitat-60%).

Elk in Nebraska: Opportunity or Another Private-Public Land Conundrum

We conducted a comprehensive research project on elk in the Pine Ridge region of northwestern Nebraska from 1995 to 2002 to determine ecological factors that could be used to improve management and reduce damage. The population ranged from 120 to 150 animals, with an average calf:cow ratio of 0.5:1 and bull:cow ratio of 0.4:1. We located 21 radio-collared female elk 6,311 times during 1995 to 1997. Seasonal home ranges of 2 herds were 10 and 44 km2, while average annual home ranges of the herds were much larger (483 and 440 km2, respectively). All wintering areas (n = 21) and 80% of the calving areas (n = 22) were located on privately-owned land. Active timber harvest temporarily displaced elk, most notably during the calving season. Elk shifted home ranges in association with the seasonal availability of agricultural crops, in particular, alfalfa, oats, and winter wheat. Population models indicated that static levels of hunting mortality would lead to a stable population of about 130 elk over 10 years. Most landowners in the Pine Ridge (57%) favored free-ranging elk, but 26% were concerned about damage to agricultural crops and competition with livestock. Habitat suitability models and estimates of social carrying capacity indicate that up to 600 elk could be sustained in the Pine Ridge without significant impacts to landowners. We recommended an integrated management program used to enhance elk habitat on publicly-owned land and redistribute elk from privately-owned land.

Studies on the Helminth Fauna of Alaska. XXXVIl. Description of Schizorchis caballeroi n. sp. (Cestoda: Anoplocephalidae), with Notes on Other Parasites of Ochotona

Schizorchis caballeroi n. sp. has been described from the collared pika, Ochotona collaris (Nelson), from Alaska, and has been distinguished morphologically from its congeners, S. ochotonae Hansen, 1948, and S. altaica Gvozdev, 1951. Nine species of helminths have been described 10 dale from North American pikas, O. collaris and O. princeps (Richardson). These mammals are markedly allopatric and do not share any species of helminth. Nematodes of two genera, Eugenuris Shults and Labiostomum Akhtar, 1941, occur in O. collaris as weIl as in palearctic species of Ochotona. This, along with other pertinent information, is taken to suggest that O. collaris has invaded North American more recently than did O. princeps or its precursor.