Geography, seasonality, and host‐associated population structure influence the fecal microbiome of a genetically depauparate Arctic mammal

Abstract

The Canadian Arctic is an extreme environment with low floral and faunal diversity characterized by major seasonal shifts in temperature, moisture, and daylight. Muskoxen (Ovibos moschatus) are one of few large herbivores able to survive this harsh environment. Microbiome research of the gastrointestinal tract may hold clues as to how muskoxen exist in the Arctic, but also how this species may respond to rapid environmental changes. In this study, we investigated the effects of season (spring/summer/winter), year (2007–2016), and host genetic structure on population‐level microbiome variation in muskoxen from the Canadian Arctic. We utilized 16S rRNA gene sequencing to characterize the fecal microbial communities of 78 male muskoxen encompassing two population genetic clusters. These clusters are defined by Arctic Mainland and Island populations, including the following: (a) two mainland sampling locations of the Northwest Territories and Nunavut and (b) four locations of Victoria Island. Between these geographic populations, we found that differences in the microbiome reflected host‐associated genetic cluster with evidence of migration. Within populations, seasonality influenced bacterial diversity with no significant differences between years of sampling. We found evidence of pathogenic bacteria, with significantly higher presence in mainland samples. Our findings demonstrate the effects of seasonality and the role of host population‐level structure in driving fecal microbiome differences in a large Arctic mammal.

Analysis of gut microbiota in three species belonging to different genera (Hemitragus, Pseudois, and Ovis) from the subfamily Caprinae in the absence of environmental variance

“…The predominant phyla in three different herbivore species were Firmicutes and Bacteroidetes, accounting for more than 90% of the intestinal flora and the result was consistent with those obtained in other studies (Chi et al, 2019;Kong et al, 2014;Ley et al, 2008;Sun et al, 2016). This is a common feature observed for herbivorous ungulates, since these two phyla play a crucial role in fiber and carbohydrate degradation (Bird et al, 2019;Brulc et al, 2009;Fernando et al, 2010).…”

“…At the family level, the relative abundance of dominant microbial species microbes showed broad consistency between the three species. For instance, Ruminococcaceae, Lachnospiraceae, Rikenellaceae, Prevotellaceae, and Bacteroidaceae were dominant families in previous study, which were also represented in our dataset (AlZahal et al., 2016 ; Bird et al., 2019 ). Of note, Ruminococcaceae and Lachnospiraceae belonging to the phylum Firmicutes were the highest relative abundance of families among the three species, whereas the remaining families belonged to the phylum Bacteroidetes.…”

Range expansion of muskox lungworms track rapid arctic warming: implications for geographic colonization under climate forcing

“…when people travel between the mainland and island 8 , or through predators (passed through gastrointestinal tract) 53 . While there is recent genetic evidence and local knowledge of muskox movement between Victoria Island and mainland 54 this appears to have been relatively rare historically 55 .…”

Gut microbiome composition predicts summer core range size in a generalist and specialist ungulate

“…In large ungulates, increasing levels of body fat is important to survive the winter when forage is limited, and may be impacted by the relative ratios of key bacterial species. In muskoxen ( Ovibos moschatus ), the abundance of Firmicutes stayed similar across seasons, while Bacteroidetes increased in the summer months, meaning the ratio of Firmicutes to Bacteroidetes is lower in the summer [67]. The ability to conserve bacteria necessary for adding fat, namely high levels of Firmicutes , while exhibiting changes in gut composition suggests ungulates can prepare for the winter even though the gut microbiome is shifting (see [39]).…”