Diet composition of moose (Alces alces) in winter, Sweden

1. Differences in botanical diet compositions among a large number of
moose fecal samples collected during winter correlated with the
nutritional differences identified in the same samples (Mantel-r = 0.89, p
= 0.001), but the nutritional differences were significantly smaller (p
< 0.001). 2. Nutritional geometry revealed that moose mixed Scots
pine Pinus sylvestris and Vaccinium spp. as nutritionally complementary
foods to reach a nutritional target resembling Salix spp. twigs, and
selected for Salix spp. browse (Jacob’s D > 0). 3. Available
protein (AP) and total non-structural carbohydrates (TNC) were
significantly correlated in observed diets but not in hypothetical diets
based on food availability. 4. The level of Acetoacetate in moose serum
(i.e., ‘starvation’) was weakly negatively associated with digestibility
of diets (p = 0.08) and unrelated to increasing AP:TNC and AP:NDF ratios
in diets (p > 0.1). 5. Our study is the first to demonstrate
complementary feeding in free-ranging moose to attain a nutritional target
that has previously been suggested in a feeding trial with captive moose.
Our results add support to the hypothesis of nutritional balancing as a
driver in the nutritional strategy of moose with implications for both the
management of moose and food resources.