There are anti wild horse people who liken wild horses and burros to an invasive species depleting the West’s resources. Craig Downer, wildlife ecologist, has recently published a scientific article on how the return of horses and burros to their species native lands has been to the good. Recommended reading for anyone who wants to comment back to the horse slaughter crowd. ~ HfH
From: Science Publishing Group
By: Craig C Downer
Abstract: Since the Wild Free-Roaming Horses and Burros Act of 1971, debate has raged over whether horses and burros are restored North American natives. Fossil, genetic and archeological evidence supports these species as native. Also, objective evaluations of their respective ecological niches and the mutual symbioses of post-gastric digesting, seminomadic equids support wild horses and burros as restorers of certain extensive North American ecosystems. A Reserve Design strategy is proposed to establish naturally self-stabilizing equine populations that are allowed to harmoniously adapt over generations within their bounded and complete habitats. These populations should meet rigid standards for viability based on IUCN SSC assessments (2,500 individuals). Basic requirements are described for successful Reserve Design including viable habitat as well as specific regions of North America where this could be implemented.
All branches of the horse family (Equidae) share an ancient evolutionary origin and long-standing duration in North America, having evolved here for ca. 60-million years ago. Few other mammalian families can lay as much claim to native status and belonging on this continent. Two other extant families in the Order Perissodactyla are the tapir and the rhinoceros families, and both are similarly rooted in North America. From George Gaylord Simpson  to Bruce MacFadden , various scientists have described the horse family’s fascinating story; and their works reveal the ascent of many distinctive yet interwoven equine genera and species over the eons.
The horse family has branched out to all continents except Australia (prior to the arrival of whites) and Antarctica. These animals have contributed positively to our planetary communities, and they continue to do so in many ways and on many levels today.
The rapid reoccupation of vacant niches in North America by the horses (Equus caballus) and burros (Equus asinus) may be viewed as corroborating their return to ancestral grounds. In the words of the Plains Indians: ‘The grass remembers the horses.’
In this article, I present evidence for the origin and longstanding evolution of both horse and burro evolutionary branches in North America, and further support the entire horse family as primarily native here. I go on to show that both horses and burros are returned native species and merit protection. In complementary fashion, I also describe the unique ecological roles filled by horses and burros, explaining how they both preserve and restore native ecosystems in the American West. Finally, I propose reserve design as a means by which wild horses and burros can restore themselves as vital components of viable ecosystems and be truly protected as mandated by the Wild Free-Roaming Horses and Burros Act of 1971. I also suggest regions where this could be possible.