Do “Excess Deer” Adversely Affect the Health of Our Forests by Causing a Decrease in Plant Diversity and Aiding in the Spread of Exotic Species?

This is the first in our series analyzing Carrboro’s Energy and Climate Protection Task Force’s Recommended Deer Cull.

Assertion 1: “Local and other studies have shown that excess deer are adversely affecting the health of our forests by causing a decrease in plant diversity and aiding in the spread of exotic species.” [page 38]

Although there are three end notes at the bottom of page 38, none of them references any studies regarding deer and their adverse affect on the health of forests.

So are “excess deer” (whatever that means) the primary cause of decreasing plant diversity and spreading of exotic species?

According to a review in the journal Science, no. “For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration.” In other words, humans are the primary cause of a decrease in plant diversity and the spreading of exotic species.

There are some good articles on the effects of deer on forest regeneration here. This study, in particular, found that “adult trees inside exclosures grew less than those directly exposed to deer. Our findings highlight the indirect effects of white-tailed deer on the growth of adult individuals of Q. rubra in a way opposite of what would be expected from previous studies based on immature or understory tree populations. We suggest the increased growth of adult trees in the presence of deer may be explained by increased nutrient inputs through deer fecal and urine deposits and the alteration of the competitive environment belowground through the reduction of understory vegetation by browsing.”

There are also studies that actually show that having too few deer negatively affects biodiversity. So the science is certainly not definitive on this issue. But the bottom line is this: deer killing programs do not permanently decrease deer population and may actually increase it over the long term, so no matter where the science (or your opinion) falls on biodiversity and forest regeneration, deer killing programs are not the answer.

We should note that this argument about biodiversity, forest regeneration, and carbon sinks is a red herring in an attempt to introduce a killing-for-fun provision into a climate and energy plan where it clearly does not belong, and in a town where it has been clearly rejected on other occasions. While hunting has gained some sort of hipster-chic among some, it is a huge stretch to convince most intelligent people that deer have anything to do with climate change.

Ten thousand years ago, 99% of zoomass was wild animals. Today, humans and the animals that we raise as food make up 98% of the zoomass. Any impact of any free-living animal on climate is modest, no matter the scale you use, compared to the impact from humans and the animals they raise to eat.

Further, free-living animals have zero carbon footprint. Every molecule of carbon they consume from the biosphere is returned to the biosphere. It is a closed-loop, 100% sustainable cycle, part of the natural carbon cycle that exists and has existed for billions of years. Only by taking sources of carbon from outside the biosphere (by digging up coal, oil, and natural gas from under ground), and releasing the carbon into the air by burning that material, can there be a carbon footprint. And by destroying approximately 36 football fields worth of trees every minute, humans shoulder the blame for destroying carbon sinks, not deer.

Finally, we should note that hunting, even bow-hunting, is not a carbon-neutral activity as practiced in 21st-century North Carolina. Hunters use fossil fuels in transporting themselves to their hunting locations with their equipment, removing and transporting the carcass to the processors, refrigerating the carcass, distributing the carcass, disposing of unused remains, and cooking the flesh. Additional fossil fuels are used in manufacturing hunting equipment and processing machinery.

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