A Perfect Storm



The following is an opinion piece submitted to us by Justin Collins. Justin is a native Washingtonian and currently works with the Timber Rattlesnake in Pennsylvania (and occasionally New Jersey), monitoring construction job sites for alternative energy sources, and doing habitat surveys throughout the state of Pennsylvania and New Jersey. In his free time he likes to study rattlesnakes, and other flora and fauna, throughout the eastern the United States. Justin can be contacted at justinian2120@hotmail.com.

Critical gestation habitat now seems to be at an ‘all-time’ premium for the Timber Rattlesnake. A relatively new combination of fire suppression, loss of habitat to development, and fragmentation of what sufficient habitat remains, has combined to create the ‘perfect storm’ for which the species does not have an effective, long- term response. There comes a point when the reduction in the quality and quantity of available basking sites begins reducing a population’s ability to give birth to the next generation successfully, thus the beginning of a marked decline in this population. Could we be at that tipping point? After studying multiple populations of Crotalus horridus throughout the central and northeastern Appalachians, I, and others with whom I compare field notes, have discussed this often and at length. There seems to be the one thing we can agree on; the answer is yes. However, there is a potential solution, and it’s a simple one to implement.

So many factors play a role in the lessening of potential basking/gestation habitat for the Timber Rattlesnake. Most of these are not new challenges for this species. Indeed some have likely been dealt with without since the species first crawled upon these soils. However, today dealing with these challenges is increasingly made impossible due to insufficient habitat with remaining habitat being fragmented and isolated.

One factor limiting Timber Rattlesnake habitat is forest succession. Succession causes sunny rock crevices to become shaded by growing trees and shrubs. This lack of sunlight reduces the amount of heat rock crevices hold, making them unsuitable for Timber Rattlesnakes. Formerly the snakes could respond by crawling to the next sufficient basking site providing the proper amount of heat needed for gestation, shedding and digestion, etc. However, fragmentation and the isolation of these sites make movement increasingly difficult.

Historically (e.g. pre-modern Caucasoid settlement and the ensuing development), wildfires started by strikes of lightning would re-open sizable chunks of canopy, most often running along ridges. Today, roads and residential developments cover many of these ridges causing effective fire breaks and, in turn, habitat fragmentation because the fire no longer spreads. More importantly, fire itself has long been effectively eliminated, removed from the natural/ecological equation, again starting with the settlement of European immigrants. Within the last hundred years, this problem was compounded by the immensely ‘successful’ campaign of misinformation featuring Smokey the Bear. The non-mast producing species such as Red Maple, Black Birch, White Birch, etc., currently thrive at levels not formerly possible when occasional wildfires kept them in check. The more fire-tolerant array of Oaks and Hickory species have been steadily giving up ground and the mast crop suffers accordingly. The loss of mast crop means the loss or decline of small mammals, a prey item for Timber Rattlesnakes.

With the encroaching development, the snakes can’t simply shift and relocate as in the days of expansive unbroken habitat- their shrinking forests have been fragmented and surrounded. We have effectively suppressed the former natural role of wildfire, which has diminished almost to the point of irrelevance, even beyond places we dwell. In the Appalachian Mountains this seems most prominent, but not exclusive in, the Allegheny Plateau, where several populations of the Timber Rattlesnake have dwindled or even disappeared in some otherwise intact areas.

Manmade clearings such as road edges, pipelines and power lines are well known sites Rattlesnakes utilize. These sites offer optimum basking conditions – a sturdy structure in full sun for 6,7,8 hours of the day, or more. But use of these sites can put snakes at higher risk of predation by their closer proximity to foot and vehicular traffic from man. These also quickly become established opportunistic hunting grounds by the Timber Rattlesnake’s myriad of natural predators. Perhaps most importantly, these sites are only beneficial to Timbers if a sufficient type of structure, ideally something permanent and large enough to prevent disturbance by predators, is present and can be used as cover by the snakes. Large rocks with a crevice small enough to prevent most predators from squeezing into seem ideal and usually appear fairly inconspicuous so as not to draw more attention than necessary. A crevice that provides the snakes with immediate access to full sun and a place to escape the direct sunlight can allow a local population the best chance of completing gestation cycles, potentially even allowing for time to forage a much needed post-partum meal before making her way back to the hibernaculum for winter. These are very important improvements, but not an ideal solution.

A better idea is improving a previously used natural site or creating new sites within relatively short distance to a known hibernaculum and off of more conspicuous sites such as the right of ways mentioned previously. This involves the removal of select trees growing to shade out these basking crevices that are essential to the survival of this species. Little can be done about this for populations on privately owned land without willing landowners. Thankfully, on state or federally owned land this is a rare and unique opportunity. As always, absolutely paramount is maintaining the secrecy of these sites’ locale; for not to do so could undermine any good that would come from such a habitat management program. Some state and federal agencies have begun putting this technique into practice on public lands in areas with severely reduced basking habitat through parts of the northeast with rapid and positive results.

Proper scouting and thorough evaluation of specific features at these sites beforehand allows this to be done very effectively with minimal disturbance to the surrounding woods. This is best done by one or two individuals who approach the site on foot – there’s no heavy machinery needed. Cut branches can be used for brush piles for additional options of cover used by both the snakes and their prey. Subsequent maintenance of these sites can be helped by treating any cut stumps with an herbicide immediately following the cutting. It’s a simple and effective forest management technique that in turn is a direct form of management for the Timber Rattlesnake. It’s one of the few things that most studying Crotalus horridus throughout the Appalachian Mountains all agree upon. We can focus on the here and now to implement an active strategy of selective cuts in areas known to have remaining populations of this heritage species we are now trying to protect. Their continued survival may actually be dependent on it.