Do nitrogen concentration and forage quality of the moss Racomitrium lanuginosum increase with latitude?

Mosses are an important component of high latitude ecosystems, contributing the majority of the plant biomass in many communities. In Arctic regions mosses also form a substantial part of the diet of many herbivore species. This may reflect either the availability of moss or its quality as forage. Here we test whether the nitrogen concentration and forage quality of the moss Racomitrium lanuginosum increase with latitude and discuss the findings with reference to herbivore utilisation of moss in the Arctic. In contrast to vascular plants, moss nitrogen concentration significantly decreased with latitude (P<.01), in line with estimates of N deposition at the sampling sites. In addition, no evidence of an increase in nutritional quality of moss with latitude was observed; thus, this study suggests that the utilisation of moss by herbivores in arctic ecosystems maybe a function of their relatively high biomass rather than their quality as forage.