Faecal nitrogen of browser and mixed feeder game species during different seasons
A practical measure of assessing periods of potential nutritional stress of game species is needed in the management of these species in the Acacia karroo Riparian Thicket of the central Free State. The objectives of the study were to determine Nf concentration of four game species (browsers and mixed feeders) during different seasons, compare Nf with leaf phenology patterns, and assess whether Nf reaches levels at which body condition loss can be expected. A seasonal pattern was observed with the lowest Nf concentrations recorded during late winter, which correlated with the seasonal phenology pattern (leaf carriage) of the winter-deciduous tree species. The Nf concentrations (g N kg−1 dung DM) of giraffe ranged from 18.3 (late winter) to 36.7 (summer) and that of kudu from 13.6 to 33.2. Likewise, the Nf of impala ranged from 16.9 to 28.0 and that of eland from 16.3 to 34.9. Access to evergreen woody species during the late-winter period proved to be essential in avoiding condition loss that corresponds with Nf levels below published critical levels (<16). In the absence of evergreen species, supplementary feeding is essential. Faecal nitrogen proved to be a useful indicator of seasonal trends in the nutritional status of browsing game species.
Keywords: browse resources, critical period, fecal crude protein, leaf carriage patterns