Re-framing deer herbivory as a natural disturbance regime with ecological and socioeconomic outcomes

[Pantheraman]

I was on a blog I occasionally browse, and I found this rather odd if not disturbing research.

https://www.fs.usda.gov/rm/pubs_journals/2022/rmrs_2022_hanberry_b009.pdf




In my opinion, just like with compassionate conservation towards invasive species and Pleistocene rewilding, I'm skeptical of this.

For one thing, the habitat modifications in the east done by humans have benefitted White-Tailed Deer because they do better in edges and transitional zones between forests and more open habitats than in mature forests because those areas have more food for them. In historic times, the forests would've been thicker than they are now for the simple reason that there weren't as many humans on the landscape. That alone should tell you deer weren't as abundant as they are now.

And second, if deer numbers east of the Mississippi are supposed to be this high, then what's with the ecological cons? Think about the wildebeests on the East African plains. With their huge numbers, one would think all of those wildebeest would hurt the ecosystem but instead, their grazing reduces fuel for wildfires and allows trees to grow, creating food and homes for many other species. This makes them a keystone species. And they aren't damaging the Serengeti ecosystem. Because this particular habitat is supposed to have a huge wildebeest population. In the case of the whitetails, we hear of how their overbrowsing negatively affects birds for example.

@birdsandbats I'm sure you'll have a few things to say about this study.

 

[birdsandbats]

This is stupid. The overabundance of deer is negatively impacting nearly every species in east to at least some extent. Calling this natural disturbance is like calling people clear-cutting a forest and building a bunch of houses a natural disturbance.

 

[Pleistohorse]

I suspect that deer numbers are probably higher at the northern limits of their ranges today. Are deer populations that much higher though in the more temperate woodlands?

I imagine that pre-1530 or so the human impact in what is now the eastern United States was not quite as light as we suspect. Large grazers like Elk and Bison were present as well. Between those two species and traditional farming methods being practiced by a larger than most people assume native population there may have been created across much of the deer’s range (again in more northerly climes probably not) conditions similar (in effect) to today.

What the Europeans encountered and what is often the baseline standard from which we measure human impact was a re-wilded post-apocalyptic environment following a devastating reduction in human population and economic disruption of native societies. Think about the timespans as well. It was another 200 years before the British were really established and another 80 years after that before the Americans really stated pushing west. That’s a lot of time for nature to rebuild itself into something the locals 300 years earlier might have thought of as a bit unnatural. Something that we ironically consider our baseline for “natural”.

Add the horse and an “unnatural” abundance of Bison in the decades after contact and entire cultures are reborn from the survivors. Regarding again, deer in the east, I’m sure they were casually farmed (we might say baited) as the natives would have altered the landscape to increase the deer’s number (almost like really free range livestock) and to attract them to a particular place to make “hunting” easier. Because with Wolves and Cougars becoming more common after the European plagues…deer would not be too complacent about predators (including large intelligent omnivorous primates).

Look to today. Between hunting, vehicle strikes, and increasingly especially among fawns predation by resurgent Coyote (little wolves) and Black Bear numbers…and habitat suppression via protected forests becoming less inviting to deer…conditions are leading to largely unrecognized, but potentially region wide declines in deer from the peaks of the 1990’s, current deer numbers are probably pretty close to the pre-European numbers.

Remember as well that the American “conservationist” perception of deer abundances are baselined to a time when the deer were recovering from their own apocalypse of market hunting, land clearing, and unrestricted (early on) subsistence hunting.

Arguably what has changed are their behaviors. Fawn mortality caused by predation suppresses numbers…but in the manner of deer…probably not adult behaviors (until the Coyotes get a bit bigger and more organized). Automobiles don’t chase deer into the woods, but might fairly mimic conditions enough to stir the deer’s traditional behaviors regarding the existence of a habitat dependent ambush predator. And hunters, nowadays, take most of the year off. Possibly factors that lead to a continent wide wolf-less Yellowstone effect on the most common herbivore.

But even then…aren’t the deer “devastating” human disturbed habitats anyway. Fixing the deer problem probably doesn’t overcome the dangerous wintering over in less economically developed countries for migrating birds, doesn’t overcome the stress to insect abundance caused by lawn farmers and as well as the Old MacDonald kind, and ignores the trending curve that will likely follow the expansion of McMansions cutting into the temporary new growth (unprotected) forests….that will not only affect the songbirds (insects more than anything though)…but watch…after a temporary perception of over abundance, deer numbers will start to trend downward too.

A “balance” probably as natural as the one we imagine from the deer scarcity of the mid-colonial years will come into being. And probably one (with protected regrowth into primary forests depleting habitat in “natural” areas and Coyotes targeting fawns in numbers greater then during the deer surge of the 1980’s and 1990’s experienced) that is less likely to support large deer numbers.

This opinion leaves out the obvious localized outlier’s of small towns with low speed limits and confined habitats were deer numbers expand exponentially…until humans intervene just before nature really takes its course. Even then the balancing trend considering all factors will be towards smaller numbers…if properly managed…and an appropriate “balance.”

Life moves across a Sea of Time and what we see as normal and natural probably isn’t and certainly won’t remain unchanging.

Probably a lot of word salad right there…but hopefully points to be considered in our pondering the natural world in between being thrilled by a really good zoo.

***sorry for the typos—-on phones I’m all thumbs***

also please be kind…it’s just an opinion.