Using next generation sequencing of alpine plants to improve fecal metabarcoding diet analysis for Dall’s sheep

Objectives Dall’s sheep (Ovis dalli dalli) are important herbivores in the mountainous ecosystems of northwestern North America, and recent declines in some populations have sparked concern. Our aim was to improve capabilities for fecal metabarcoding diet analysis of Dall’s sheep and other herbivores by contributing new sequence data for arctic and alpine plants. This expanded reference library will provide critical reference sequence data that will facilitate metabarcoding diet analysis of Dall’s sheep and thus improve understanding of plant-animal interactions in a region undergoing rapid climate change. Data description We provide sequences for the chloroplast rbcL gene of 16 arctic-alpine vascular plant species that are known to comprise the diet of Dall’s sheep. These sequences contribute to a growing reference library that can be used in diet studies of arctic herbivores.

Redescription of Polyplastron alaskum Dehority, 1974 (Ciliophora, Entodiniomorphida), a Rare Rumen Ciliate Species from Domestic and Wild Sheep

The present study redescribes the species Polyplastron alaskum based on morphological characterization and provides, for the first time, data on its infraciliary bands pattern. Polyplastron alaskum was described in Alaskan dall montain sheep (Ovis dalli), and registered again only in the present study, 45 years later, inhabiting the rumen contents of domestic sheep (Ovis aries) in northeastern Brazil. All the taxonomic characters observed in the original description was observed in the present study. The infraciliary pattern in Polyplastron alaskum is slightly different of Diplodinium-type, observed in some ophryoscolecids belonging to the subfamily Diplodiniinae.

Critical snow density threshold for Dall’s sheep (Ovis dalli dalli)

Snow cover can significantly impact animal movement and energetics, yet few studies have investigated the link between physical properties of snow and energetic costs. Quantification of thresholds in snow properties that influence animal movement are needed to help address this knowledge gap. Recent population declines of Dall’s sheep (Ovis dalli dalli Nelson, 1884) could be due in part to changing snow conditions. We examined the effect of snow density, snow depth, and snow hardness on sinking depths of Dall’s sheep tracks encountered in Wrangell–St. Elias National Park and Preserve, Alaska. Snow depth was a poor predictor of sinking depths of sheep tracks (R2 = 0.02, p = 0.38), as was mean weighted hardness (R2 = 0.09, p = 0.07). Across competing models, top layer snow density (0–10 cm) and sheep age class were the best predictors of track sink depths (R2 = 0.58). Track sink depth decreased with increasing snow density, and the snowpack supported the mass of a sheep above a density threshold of 329 ± 18 kg/m3 (mean ± SE). This threshold could aid interpretation of winter movement and energetic costs by animals, thus improving our ability to predict consequences of changing snowpack conditions on wildlife.