Variation in age of primiparity in mountain goats estimated from horn growth increments

Variation in age of primiparity is important for population dynamics and wildlife management because it can affect population growth. Using a novel technique based on the trade-off between annual horn growth and reproduction, we estimated the age of primiparity for 2274 female mountain goats (Oreamnos americanus, de Blainville 1816) harvested across British Columbia, Canada, from 1976 to 2019. We then investigated spatio-temporal variation in the probability that harvested females were primiparous when aged three, four or five years and older using Bayesian ordinal regressions. We found that the probability of primiparity at three years decreased over time in nearly all mountain ranges. In the Coastal Mountain range, however, the probability of primiparity at age three significantly increased. These results suggest that the large coastal populations of mountain goats could be more resilient to harvest than other populations in British Columbia, which may be experiencing environmental effects promoting later primiparity. Models predicting age of primiparity from annual growth measures are a valuable tool for wildlife management and could help conservation of many species.

Genome Assembly and Analysis of the North American Mountain Goat (Oreamnos americanus) Reveals Species-Level Responses to Extreme Environments

The North American mountain goat (Oreamnos americanus) is an iconic alpine species that faces stressors from climate change, industrial development, and recreational activities. This species’ phylogenetic position within the Caprinae lineage has not been resolved and their phylogeographic history is dynamic and controversial. Genomic data could be used to address these questions and provide valuable insights to conservation and management initiatives. We sequenced short-read genomic libraries constructed from a DNA sample of a 2.5-year-old female mountain goat at 80X coverage. We improved the short-read assembly by generating Chicago library data and scaffolding using the HiRise approach. The final assembly was 2,506 Mbp in length with an N50 of 66.6 Mbp, which is within the length range and in the upper quartile for N50 published ungulate genome assemblies. Comparative analysis identified 84 gene families unique to the mountain goat. The species demographic history in terms of effective population size generally mirrored climatic trends over the past one hundred thousand years and showed a sharp decline during the last glacial maximum. This genome assembly will provide a reference basis for future population and comparative genomic analyses.

Food habits of the Japanese serow (Capricornis crispus) in an alpine habitat on Mount Asama, central Japan

We investigated the food habits of the Japanese serow (Capricornis crispus) in alpine habitats using direct observations at Mount Asama, central Japan. We observed the feeding behavior of 13 identified adult serows throughout the year, from April 2016 to October 2017. The animals’ food habits were evaluated by the feeding probability among 2129 observation bouts. The most important food throughout the year was grasses (feeding probability, 57.6%), followed by forbs (43.5%) and dwarf bamboos (11.4%). However, the feeding probability for each food category drastically changed in relation to the season; in particular, grasses and forbs were especially important foods from spring to autumn, whereas dwarf bamboos and conifers were important in winter. These results suggest that the food habits of the serow are flexible and will vary according to seasonal changes in vegetation. The findings also suggest that the feeding ecology of the serow in an alpine area tends to match that of an intermediate feeder rather than a browser, as was reported by several previous studies conducted in forested habitats. However, the food habits of the serows in the alpine habitats were similar to those of other alpine caprids, such as the mountain goat (Oreamnos americanus), alpine chamois (Rupicapra rupicapra) and Pyrenean chamois (Rupicapra pyrenaica). This is the first study to demonstrate that the food habits of the serow are variable according to the season and/or population. Similar to other alpine caprids, the flexible food habits of the serow in alpine habitats are likely an adaptation to an environment with a characteristically unstable food supply.

Space, time and captivity: quantifying the factors influencing the fecal microbiome of an alpine ungulate

ABSTRACT The community of microorganisms in the gut is affected by host species, diet and environment and is linked to normal functioning of the host organism. Although the microbiome fluctuates in response to host demands and environmental changes, there are core groups of microorganisms that remain relatively constant throughout the hosts lifetime. Ruminants are mammals that rely on highly specialized digestive and metabolic modifications, including microbiome adaptations, to persist in extreme environments. Here, we assayed the fecal microbiome of four mountain goat (Oreamnos americanus) populations in western North America. We quantified fecal microbiome diversity and composition among groups in the wild and captivity, across populations and in a single group over time. There were no differences in community evenness or diversity across groups, although we observed a decreasing diversity trend across summer months. Pairwise sample estimates grouped the captive population distinctly from the wild populations, and moderately grouped the southern wild group distinctly from the two northern wild populations. We identified 33 genera modified by captivity, with major differences in key groups associated with cellulose degradation that likely reflect differences in diet. Our findings are consistent with other ruminant studies and provide baseline microbiome data in this enigmatic species, offering valuable insights into the health of wild alpine ungulates.