Feral horse density-impact functions: a critique of Berman et al . 2023

Berman et al . (2023) estimated density-impact functions for three of the impacts of feral horse populations in the Australian Alps National Parks. They identified a threshold of 250 faecal piles ha -1 , which they equated to 9 feral horses km -2 , below which the authors concluded that horses could be retained with minimum impact. This critique examines the study’s measures of impact, and its statistical procedures and reporting. We conclude that there are many reasons for caution about the use of the results and that the recommended management threshold of 9 feral horses km -2 should be disregarded.