  We have shown that commonly used model-fitting methods fail when the
underlying ecological system is chaotic. Importantly, Hartig & Dormann
[arXiv:1305.3544] suggest an alternative method that is able to overcome this
problem for the logistic model when the "true model" is known. This is
encouraging, however the more relevant test is of the method when the "true
model" is unknown, as it always is for real ecosystems. By making a small
modification to the "true model," we find that the suggested method provides
inaccurate forecasts and severely biased estimates of the ecological dynamics.
In contrast, a model-free approach is able to provide accurate forecasts and a
useful foundation for ecological understanding without the burdensome
assumption of a "true model."
