Forage Quality of Carex macrochaeta Emerging from Alaskan Alpine Snowbanks through the Summer

Abstract

-CareX macrochaeta is a common species and an important item of summer forage for mountain goats Oreamnos americanus in SE Alaska. Continuous sprouting of these plants from the edges of melting snowbanks through the summer poses the question as to whether their quality as forage differs relative to date of growth initiation. Chemical composition and digestibility of C. macrochaeta taken from a S-facing alpine meadow were measured from plants collected on three different snowmelt dates and subsequently at approximately 21-day intervals through the summer period. There were no significant differences in nitrogen content, other chemical constituents, or fiber content associated with date of growth initiation. Nitrogen content was greater at this alpine, S-facing slope than at a nearby and slightly lower N-facing slope. As expected, nitrogen and phosphorus content decreased during phenological progression, whereas calcium and fiber content increased. Crude protein and phosphorus levels and the proportion of digestible components in the new-growth C. macrochaeta were at the upper limits for graminoid species reported in the literature, indicating high nutritional value. Because plant growth initiation associated with snowbank disappearance can continue through August in SE Alaska, highly nutritional food is available for mountain goats through the entire summer.