The ability of winter grazing to reduce wildfire size and fire-induced plant mortality was not demonstrated: a comment on Davies et al. (2015)

A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behaviour
and intensity metrics, and fire-induced plant mortality in shrub–grasslands. The authors concluded that ungrazed
rangelands may experience fire-induced mortality of native perennial bunchgrasses. The authors also presented several
statements regarding the benefits of winter grazing on post-fire plant community responses. However, we contend that the
study by Davies et al. has underlying methodological errors, lacks data necessary to support their conclusions, and does not
provide a thorough discussion on the effect of grazing on rangeland ecosystems. Importantly, Davies et al. presented no
data on the post-fire mortality of the perennial bunchgrasses or on the changes in plant community composition following
their experimental fires. Rather, Davies et al. inferred these conclusions based on their observed fire behaviour metrics of
maximum temperature and a term described as the ‘heat load’. However, we contend that neither metric is appropriate for
describing the heat flux impacts on plants. This lack of post-fire data, several methodological errors and the use of
inappropriate thermal metrics limit the authors’ ability to support their stated conclusions