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Foods, macronutrients and fibre in the diet of blue sheep (Psuedois nayaur) in the Annapurna Conservation Area of Nepal.

Aryal A, Coogan SC, Ji W, Rothman JM, Raubenheimer D - Ecol Evol (2015)

Bottom Line: Analysis of fiber balance showed that the two most consumed plants of blue sheep (i.e., Kobresia spp. and Carex spp.) contained the highest concentration of hemicellulose, which is likely digestible by blue sheep.The hemicellulose and lignin balance of plants ranged relatively widely, yet their cellulose contents showed less variation.Foraging by blue sheep may therefore be a balance between consuming highly digestible high-carbohydrate plants and plants less-digestible but higher in protein and/or lipid.

View Article: PubMed Central - PubMed

Affiliation: Institute of Natural and Mathematical Sciences Massey University Auckland New Zealand.

ABSTRACT
Food resources are often critical regulating factors affecting individual fitness and population densities. In the Himalayan Mountains, Bharal "blue sheep" (Pseudois nayaur) are the main food resource for the endangered snow leopard (Panthera uncia), as well as being preyed upon by other predators. Blue sheep, however, may face a number of challenges including food resource competition with other wild and domestic ungulates, and hunting pressure. Here, we characterized the diet of blue sheep in the Annapurna Conservation Area (ACA) of Nepal and conducted proximate nutritional analysis on a limited number of plants identified as foods. Furthermore, we investigated the macronutrient and fiber balance of these plants using nutritional geometry which is a state-space approach to modeling multidimensional and interactive nutritional aspects of foraging. A total of 19 plant species/genera were identified in blue sheep pellets using microhistological analysis. On average, across seasons and regions of the study area, the two most frequently occurring plants in pellets were graminoids: Kobressia sp. and Carex spp. The macronutrient balance of Kobresia sp. was relatively high in carbohydrate and low in protein, while other plants in the diet were generally higher in protein and lipid content. Analysis of fiber balance showed that the two most consumed plants of blue sheep (i.e., Kobresia spp. and Carex spp.) contained the highest concentration of hemicellulose, which is likely digestible by blue sheep. The hemicellulose and lignin balance of plants ranged relatively widely, yet their cellulose contents showed less variation. Foraging by blue sheep may therefore be a balance between consuming highly digestible high-carbohydrate plants and plants less-digestible but higher in protein and/or lipid.

No MeSH data available.


(A) Right‐angled mixture triangle (Raubenheimer 2011) showing the macronutrient balance of plants consumed by blue sheep (Pseudois nayaur). Macronutrients are expressed as percentage of total macronutrients (i.e.,. protein + fat + carbohydrate). Protein is shown on the implicit z‐axis, the value of which is inversely related with distance from the origin. A dashed gray line indicating 10% protein is shown for reference. The plant genus found most frequently in the diet of blue sheep (Kobresia spp.) is shown as a red symbol; (B) A close‐up of the region of nutrient space occupied by plants consumed by blue sheep [legend provided in panel (A)]. Macronutrient estimates are color‐coded to match the month in which the sample was collected. All data points represent a single sample.
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ece31661-fig-0002: (A) Right‐angled mixture triangle (Raubenheimer 2011) showing the macronutrient balance of plants consumed by blue sheep (Pseudois nayaur). Macronutrients are expressed as percentage of total macronutrients (i.e.,. protein + fat + carbohydrate). Protein is shown on the implicit z‐axis, the value of which is inversely related with distance from the origin. A dashed gray line indicating 10% protein is shown for reference. The plant genus found most frequently in the diet of blue sheep (Kobresia spp.) is shown as a red symbol; (B) A close‐up of the region of nutrient space occupied by plants consumed by blue sheep [legend provided in panel (A)]. Macronutrient estimates are color‐coded to match the month in which the sample was collected. All data points represent a single sample.

Mentions: We performed nutritional analysis on a limited number of plants collected from the Mustang and Manang districts in January, March, June/July, and November (macronutrients in Table 2; and fiber in Table 3) and were thus limited in the ability to make comparisons with diet RF and between seasons and regions of the study area; however, patterns emerged in our RMT analysis of macronutrients (Fig. 2) and fiber (Fig. 3) despite these limitations. For example, the macronutrient balance of Kobresia spp., the most consumed (i.e., highest relative frequency) plant food, was relatively high in carbohydrate and low in protein content compared to other plants found in the diet of blue sheep, and the macronutrient balance changed little between November and January samples (Fig. 2A and B). The second most frequently consumed plant, Carex spp., was relatively similar to Kobresia spp. in protein content but lower in lipid during March, but a sample of Carex spp. from November showed a much higher protein balance (Figure 2a,b). The RMT analysis of fiber balance showed that the two most consumed plants of blue sheep, Kobresia spp. and Carex spp. (which together had a relative frequency of 34.5 with CF) contained the highest amounts of hemicellulose, which was relatively constant across sampling periods (Fig. 3A and B). The hemicellulose and lignin balance of plants ranged relatively widely, yet the cellulose content of plants showed less variation, being more tightly aligned along the z‐axis at approximately 40% cellulose content (Fig. 3A and B). The hemicellulose balance of plant samples varied inversely with macronutrient balance (Fig. 4): plants that were higher in macronutrients (protein, fat, and carbohydrates) balance had lower hemicellulose balance, while plants that were lower in macronutrient balance had higher hemicellulose balance.


Foods, macronutrients and fibre in the diet of blue sheep (Psuedois nayaur) in the Annapurna Conservation Area of Nepal.

Aryal A, Coogan SC, Ji W, Rothman JM, Raubenheimer D - Ecol Evol (2015)

(A) Right‐angled mixture triangle (Raubenheimer 2011) showing the macronutrient balance of plants consumed by blue sheep (Pseudois nayaur). Macronutrients are expressed as percentage of total macronutrients (i.e.,. protein + fat + carbohydrate). Protein is shown on the implicit z‐axis, the value of which is inversely related with distance from the origin. A dashed gray line indicating 10% protein is shown for reference. The plant genus found most frequently in the diet of blue sheep (Kobresia spp.) is shown as a red symbol; (B) A close‐up of the region of nutrient space occupied by plants consumed by blue sheep [legend provided in panel (A)]. Macronutrient estimates are color‐coded to match the month in which the sample was collected. All data points represent a single sample.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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ece31661-fig-0002: (A) Right‐angled mixture triangle (Raubenheimer 2011) showing the macronutrient balance of plants consumed by blue sheep (Pseudois nayaur). Macronutrients are expressed as percentage of total macronutrients (i.e.,. protein + fat + carbohydrate). Protein is shown on the implicit z‐axis, the value of which is inversely related with distance from the origin. A dashed gray line indicating 10% protein is shown for reference. The plant genus found most frequently in the diet of blue sheep (Kobresia spp.) is shown as a red symbol; (B) A close‐up of the region of nutrient space occupied by plants consumed by blue sheep [legend provided in panel (A)]. Macronutrient estimates are color‐coded to match the month in which the sample was collected. All data points represent a single sample.
Mentions: We performed nutritional analysis on a limited number of plants collected from the Mustang and Manang districts in January, March, June/July, and November (macronutrients in Table 2; and fiber in Table 3) and were thus limited in the ability to make comparisons with diet RF and between seasons and regions of the study area; however, patterns emerged in our RMT analysis of macronutrients (Fig. 2) and fiber (Fig. 3) despite these limitations. For example, the macronutrient balance of Kobresia spp., the most consumed (i.e., highest relative frequency) plant food, was relatively high in carbohydrate and low in protein content compared to other plants found in the diet of blue sheep, and the macronutrient balance changed little between November and January samples (Fig. 2A and B). The second most frequently consumed plant, Carex spp., was relatively similar to Kobresia spp. in protein content but lower in lipid during March, but a sample of Carex spp. from November showed a much higher protein balance (Figure 2a,b). The RMT analysis of fiber balance showed that the two most consumed plants of blue sheep, Kobresia spp. and Carex spp. (which together had a relative frequency of 34.5 with CF) contained the highest amounts of hemicellulose, which was relatively constant across sampling periods (Fig. 3A and B). The hemicellulose and lignin balance of plants ranged relatively widely, yet the cellulose content of plants showed less variation, being more tightly aligned along the z‐axis at approximately 40% cellulose content (Fig. 3A and B). The hemicellulose balance of plant samples varied inversely with macronutrient balance (Fig. 4): plants that were higher in macronutrients (protein, fat, and carbohydrates) balance had lower hemicellulose balance, while plants that were lower in macronutrient balance had higher hemicellulose balance.

Bottom Line: Analysis of fiber balance showed that the two most consumed plants of blue sheep (i.e., Kobresia spp. and Carex spp.) contained the highest concentration of hemicellulose, which is likely digestible by blue sheep.The hemicellulose and lignin balance of plants ranged relatively widely, yet their cellulose contents showed less variation.Foraging by blue sheep may therefore be a balance between consuming highly digestible high-carbohydrate plants and plants less-digestible but higher in protein and/or lipid.

View Article: PubMed Central - PubMed

Affiliation: Institute of Natural and Mathematical Sciences Massey University Auckland New Zealand.

ABSTRACT
Food resources are often critical regulating factors affecting individual fitness and population densities. In the Himalayan Mountains, Bharal "blue sheep" (Pseudois nayaur) are the main food resource for the endangered snow leopard (Panthera uncia), as well as being preyed upon by other predators. Blue sheep, however, may face a number of challenges including food resource competition with other wild and domestic ungulates, and hunting pressure. Here, we characterized the diet of blue sheep in the Annapurna Conservation Area (ACA) of Nepal and conducted proximate nutritional analysis on a limited number of plants identified as foods. Furthermore, we investigated the macronutrient and fiber balance of these plants using nutritional geometry which is a state-space approach to modeling multidimensional and interactive nutritional aspects of foraging. A total of 19 plant species/genera were identified in blue sheep pellets using microhistological analysis. On average, across seasons and regions of the study area, the two most frequently occurring plants in pellets were graminoids: Kobressia sp. and Carex spp. The macronutrient balance of Kobresia sp. was relatively high in carbohydrate and low in protein, while other plants in the diet were generally higher in protein and lipid content. Analysis of fiber balance showed that the two most consumed plants of blue sheep (i.e., Kobresia spp. and Carex spp.) contained the highest concentration of hemicellulose, which is likely digestible by blue sheep. The hemicellulose and lignin balance of plants ranged relatively widely, yet their cellulose contents showed less variation. Foraging by blue sheep may therefore be a balance between consuming highly digestible high-carbohydrate plants and plants less-digestible but higher in protein and/or lipid.

No MeSH data available.