Robert Bauer is a biologist whose works have been published before on Habitat for Horses. Today’s article is on the myth of overpopulation of wild horses. He, and other prominent biologists, claim that the actual numbers of wild horses is so low that the use PZP contraceptives will greatly increase the likelihood of the total destruction of the wild horses of the West. ~ HfH
By: Robert Bauer
The passion of my heart is, and has been, to emphasize how nature through its own mechanisms will and should be allowed, to maintain natural ecological balance, without human intervention. It does this through physiological differences, found within each species inside any given ecosystem. Each of those differences, contribute as a vital factor in a broad ecological equation. It also accomplishes this through the numbers or density of any given species of animal or plant within that system, in conjunction with competitive species, and the carrying capacity of the land. There is a misconception, even amongst advocates of the wild horses, that the only things that are necessary to check wild equine population growth is the presence of its predators and or natural environmental factors. Although, natural predation is important and environmental impacts, density dependent inhibition plays an important role also. In this scenario, what that means is that the numbers or density of wild equine, versus competing ruminants, such as the pronghorn, each will fluctuate in response to the other based upon the carrying capacity of the land, yet always in perfect balance. In essence, the pronghorn need the presence of wild horses and burros, just as much as the wild horses need the pronghorn. Each population will have the effect of keeping the numbers of another competing population at levels that are ideal for the carrying capacity of the land.
Also, what must be understood is that nature is dynamic, and not static. This infers that it continuously fluctuates and adjusts, through its own negative and positive feedback loops, from the molecular, all the way up the scale of organisms. Because it is dynamic and not static means that its functions cannot be confined to finite thinking, and fixed statistics but must be allowed, through its own mechanisms to maintain itself, hands off, so to speak. In other words, nature cannot be limited at any given time to a given number, or average of numbers, that mankind deems appropriate. An example of this is the Bureau of Land Management’s, “Appropriate Management Level“, of wild horses in their legally designated lands. Mankind’s sole responsibility has to be focused on keeping the restrictions off of nature, so that nature can be itself, and not an offspring of man’s seemingly brilliance. The moment mankind seeks to alter nature according to a fixed number, or an average of numbers, is the moment that nature and balance itself begins to break down. At first it occurs little by little, yet as artificial alteration persists, the breakdowns become greater and greater. This has occurred in every branch of nature, where mankind has endeavored to manage natural balance, assuming nature to be static and not dynamic.
With these thoughts in mind as an introduction, the tenacious destruction of a vital component of nature’s beauty and balance continues to be removed from the rangelands of the west, even the wild horses and wild burros, by the Bureau of Land Management. It has turned a blind side to the solid science that opposes the idea that these creatures are a detriment to the ecosystems they exist in. Just as much, it is opposed so to the myth that there is over population of our wild equine. The ludicrous concept of the “Appropriate Management Level”, of wild horses in any area out west is a lie concocted by the bureau. This is based upon how much forage that the BLM is going to allow the mustangs, as opposed to how much they would actually consume. This is opposed to cattle and other competing ruminants in these same areas, which are allocated by this same bureau, the major percentage of the forage. From this comes the propaganda that there exists overpopulation of wild Equids, and the subsequent removal of them in mass, from their legally designated lands. This, the bureau does regardless of the fact that our wild horses and burros, by law, are to be considered as the principle species in a multi use situation. This is all accomplished to accommodate the Bureau of Land Management’s leasing of those same lands for cattle and cattle ranchers, for energy interests, and big horn sheep hunters.
In a desperate attempt to curb the devastating roundups many advocates are succumbing to the pressure of the BLM to utilize the PZP contraceptive on our wild horses. This thinking may be based on a heartfelt love for our wild ones, but also with the idea that a compromise in this area will at least preserve them in the wild. There are those that believe that the roundups have already decreased because of this compromise to use the contraceptive. As a biologist I would ask all to consider some truths concerning this issue.
First, the numbers of the wild horses remaining in the wild are not the 20,000 to 30,000 that many assert are out there. The numbers of our wild ones are not even in the tens of thousands anymore. This has its basis upon the liberal use of PZP, the thousands of wild horses and burros already removed, and the adjustment of sex ratios. Added to this, are mortality rates in the wild that range between 19% to 75% annually, both first year and adult. The reasons that the roundups have decreased is simple because the wild horses remaining in the wild are so few, they can’t be found. This is despite the continued propaganda that there is still overpopulation.
Secondly, with continued use of the PZP contraceptive, population growth will be driven down even further, in as much as reproduction will continue to decrease dramatically because of PZP, but mortality percentages will remain the same. In essence, mortality will completely overwhelm reproduction and accelerate the population decline. Added to this will be the increased chances of the loss of genetic viability. All of this the BLM is fully aware of, however not unlike our Native American ancestors, the U.S. government promises a compromise but are taking a 100 miles for every mile we give them.
The roundups will continue, even though the wild horses are fewer in number. There doesn’t have to be many roundups, however, to decimate our wild horse herds with what few numbers are out there, especially with an even more rapid decline in population growth and the threat of inbreeding. The proponents of PZP, whether they love our wild horses or not, will be aiding the BLM in driving them to extinction. The only answer is to continue fighting for the truth, and to allow nature to remain untouched. The wild horses and burros will continue as the poetically beautiful, yet vital components of ecological balance if, and only if, we allow nature alone, through its own dynamic methods to dictate the numbers in the wild that are to exist, at any given time.
Acknowledgments: Craig Downer, Wildlife Ecologist