Guest Column: The effects of deer overpopulation

01/25/2015 8:00 AM |
Two deer grazing behind a Cutchogue home last year. (Credit: Katharine Schroeder, file)

Two deer grazing behind a Cutchogue home last year. (Credit: Katharine Schroeder, file)

The overpopulation of deer is increasingly affecting the human and natural landscape in Southold Town. It is directly and indirectly impacting our water quality, our shoreline bluffs, headlands and wetlands.

And so it affects each one of us who live on and love the East End. Some say the end of the whitetail deer problem is many years away. Others suggest it is coming sooner, with changes in land use practices such as fencing or deer resistant plants or changes in hunting or culling practices. Still others think it is merely a matter of time before predation, starvation or disease take their toll. Coyotes are reportedly now present in Nassau County and serious viral diseases of deer have recently shown up in upstate New York. Closer to home, some seek to stabilize deer numbers through sterilization and the dispensing of pesticides to control the insect and arthropod vectors of disease. For a problem that seems to have no end in sight, I want to take to take this opportunity to discuss the ends of the deer that are in sight, more specifically the front and back end that are increasingly degrading woodland, coastal and water quality resources in Southold.

WATER QUALITY AND SHELLFISH

The Southold Town shellfish advisory committee has been DNA-sampling our waters for the last two years in cooperation with the Cornell Cooperative Extension marine program. Employing a DNA-based science called microbial source tracking to enumerate the fecal coliform indicator bacteria in water — which the state Department of Environmental Conservation uses to effect shellfish closures — the DNA in a water sample can be amplified and split into component fractions and “tracked” via computer back to human or animal specie source(s). As all the bacteria of the fecal coliform group count equally against the shellfish standard, each additional fecal coliform showing up in the water can put a sample “over the top” for shellfish harvest purposes.

Cornell’s MST tracking system is considered a “first generation” tool. Its strong point is a “library” of “local” bacterial DNA and it can directly implicate deer and/or generic wildlife contamination depending on the return from the statistical analysis. “Hits” from wildlife and deer bacterial DNA have been reported in the 2013 data as well as in preliminary returns from our 2014 testing. The highest bacterial counts are typically found in the headwaters of our creeks. This coincides with visual observations that our deer herd is spending increasing amounts of time near those headwaters and in wetlands — likely forced there by land development, defensive fencing practices and their habit of devouring the under-story vegetation of many adjacent woodlands they previously occupied. Deer trails and deer bedding areas among stands of invasive common reed phragmites near our creeks are increasingly being used not only by deer but by other animals that are forced there during the day due to this loss of forest cover. More animals mean potentially more fecal coliforms getting in our waterways — and less clamming. Data analysis by committee members suggests that some shellfishing areas in Southold Town are not nearly as impacted by rainfall and road runoff as previously assumed, possibly implicating direct deposition of wastes in wetlands, interacting with higher-than-normal water levels and tides, as the primary source of water quality degradation.

BLUFFS AND HEADLANDS

With increasing frequency, the Southold Town Trustees and Conservation Advisory Council are encountering deer, or the evidence of deer, during monthly field inspections. Deer can damage headlands and bluffs through their system of trails and over-browsing of vegetation on trails. Their repeated running over the crest of the Long Island Sound bluff has been found to cause failure of soils and vegetation, leading to what are known as a “blow outs.”

Unfortunately, these areas are difficult to restore, even with repeated grooming and re-vegetation, since the deer promptly trample or eat the repairs. Property line fences often amplify this problem, as they tend to concentrate the deer toward the bluff face. Fencing restrictions in the town wetlands code designed to protect bluffs and provide for the needs of wildlife make correcting these problems particularly difficult to solve, as fencing is not permitted on the crest of the bluff.

PERMANENT CHANGES

Whitetail deer, which are most closely related to goats, have displayed an amazing ability to eat new “stuff.” Ask any gardener or farmer! Their four-chambered rumen “stomach” has a diverse micro-flora and fauna of bacteria and protozoa that are highly adaptable to new foods after they become acclimated to them. Once on the menu, neither the deer nor his/her gut seems to forget what can be turned into fuel. While plants that inhabit the salt marsh, inundated regularly by tides, do not yet appear to be on the menu, who knows? Adjacent upland deer have found almost everything to be edible. Areas that used to be oak-hickory forests with a thick under-story of beneficial native vegetation — such as wild blueberries and huckleberries that provide food and nesting sites for birds, butterflies and the like — are now devoid of vegetation or are being overtaken by invasive plant species such as phragmites or the recently arrived mile-a-minute vine.

Plants attempting to colonize disturbed soils and open farm fields, known as the “Old Field Succession,” no longer go through a succession of species over time. In Southold, this succession typically started with mixtures of grasses and legumes, leading to bayberries, cedars and native brambles and eventually to larger trees and healthy forest. Our most distressed fields in Southold are now undergoing a form of reverse succession where there are no (or severely stunted) cedars or bayberries and only sparse plant cover consisting of coarse or non-native grasses and non-native brambles. Soils exposed by persistent over-grazing are more likely to erode, undergo harmful changes in soil chemistry and biology and themselves be more likely colonized by undesirable invasive vegetation.

No matter which end is up or down, in sight or not, these are some of the implications of the deer increasingly affecting the human and natural landscape in Southold Town. As much of the land in Southold Town is privately owned, deer management by private landowners is extremely important in reducing the local deer population.

If you have a parcel that routinely hosts a number of deer and you are interested in having a hunter hunt your property, please call Southold Town at 631- 765-1283, and they can assist you with contact information.

bredemeyerJohn Bredemeyer is president of the Southold Town Trustees and chairman of the Southold Town shellfish advisory committee. He retired from the Suffolk County health department’s office of ecology marine unit in 2010. This column is the third in a series of six Guest Spots being submitted by the North Fork Deer Management Alliance. They are being published over the course of six months.

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