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Climatic warming and the future of bison as grazers.

Craine JM, Towne EG, Miller M, Fierer N - Sci Rep (2015)

Bottom Line: Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality.Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots.Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass.

View Article: PubMed Central - PubMed

Affiliation: Jonah Ventures, Manhattan KS 66502, USA.

ABSTRACT
Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores.

No MeSH data available.


Related in: MedlinePlus

Seasonal pattern of relative read abundances (RRAs) for Kansas bison in 2011, 2013, and 2014.(a) C3 graminoids, (b) C4 grasses, (c) non-N2-fixing forbs, and (d) N2-fixing species. Each point is the abundance of sequences pooled across multiple males or females at a given time point.
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f3: Seasonal pattern of relative read abundances (RRAs) for Kansas bison in 2011, 2013, and 2014.(a) C3 graminoids, (b) C4 grasses, (c) non-N2-fixing forbs, and (d) N2-fixing species. Each point is the abundance of sequences pooled across multiple males or females at a given time point.

Mentions: N2-fixing species dominated Kansas bison RRA in spring and fall. The seasonal abundance of N2-fixing species in the diet was bimodal with RRA peaks of ~70% in late April and ~60% in late September (Fig. 1). The seasonal peak usage was consistent across all three sampling years (Fig. 3). Controlling for day of year and sex of the animal, there were no significant differences among years in C3 graminoids, or eudicots (P > 0.05). In 2011 compared to 2013 or 2014, C4 grasses were a lower proportion of the diet (P < 0.001) and N2-fixers were a higher proportion of the diet (P = 0.001).


Climatic warming and the future of bison as grazers.

Craine JM, Towne EG, Miller M, Fierer N - Sci Rep (2015)

Seasonal pattern of relative read abundances (RRAs) for Kansas bison in 2011, 2013, and 2014.(a) C3 graminoids, (b) C4 grasses, (c) non-N2-fixing forbs, and (d) N2-fixing species. Each point is the abundance of sequences pooled across multiple males or females at a given time point.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645125&req=5

f3: Seasonal pattern of relative read abundances (RRAs) for Kansas bison in 2011, 2013, and 2014.(a) C3 graminoids, (b) C4 grasses, (c) non-N2-fixing forbs, and (d) N2-fixing species. Each point is the abundance of sequences pooled across multiple males or females at a given time point.
Mentions: N2-fixing species dominated Kansas bison RRA in spring and fall. The seasonal abundance of N2-fixing species in the diet was bimodal with RRA peaks of ~70% in late April and ~60% in late September (Fig. 1). The seasonal peak usage was consistent across all three sampling years (Fig. 3). Controlling for day of year and sex of the animal, there were no significant differences among years in C3 graminoids, or eudicots (P > 0.05). In 2011 compared to 2013 or 2014, C4 grasses were a lower proportion of the diet (P < 0.001) and N2-fixers were a higher proportion of the diet (P = 0.001).

Bottom Line: Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality.Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots.Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass.

View Article: PubMed Central - PubMed

Affiliation: Jonah Ventures, Manhattan KS 66502, USA.

ABSTRACT
Climatic warming is likely to exacerbate nutritional stress and reduce weight gain in large mammalian herbivores by reducing plant nutritional quality. Yet accurate predictions of the effects of climatic warming on herbivores are limited by a poor understanding of how herbivore diet varies along climate gradients. We utilized DNA metabarcoding to reconstruct seasonal variation in the diet of North American bison (Bison bison) in two grasslands that differ in mean annual temperature by 6 °C. Here, we show that associated with greater nutritional stress in warmer climates, bison consistently consumed fewer graminoids and more shrubs and forbs, i.e. eudicots. Bison in the warmer grassland consumed a lower proportion of C3 grass, but not a greater proportion of C4 grass. Instead, bison diet in the warmer grassland had a greater proportion of N2-fixing eudicots, regularly comprising >60% of their protein intake in spring and fall. Although bison have been considered strict grazers, as climatic warming reduces grass protein concentrations, bison may have to attempt to compensate by grazing less and browsing more. Promotion of high-protein, palatable eudicots or increasing the protein concentrations of grasses will be critical to minimizing warming-imposed nutritional stress for bison and perhaps other large mammalian herbivores.

No MeSH data available.


Related in: MedlinePlus