Effects of off-road vehicles on reproductive success of pine snakes (<Emphasis Type="Italic">Pituophus melanoleucus</Emphasis>) in the New Jersey pinelands

Considerable attention has been devoted to the effects of people and their vehicles on birds and mammals, but possible effects on reptiles in populated areas have received less attention. Moreover, the effects of human activities on reptile reproductive success itself has been harder to demonstrate. This paper examines the effect of management of off-road vehicles in New Jersey’s pinelands on the reproductive success of pine snakes (Pituophus melanoleucus) from 1986 to 2005. We used the percentage of snakes in each hibernaculum that were young of the year (hatchlings) as an indicator of reproductive success, and compared this percent for five hibernacula that were in an area with varying degrees of off-road vehicle (ORV) disturbance, with 12 hibernacula in areas with no ORV disturbances (reference sites). This percent took into account differences in absolute numbers from one location to another, and over time due to hibernacula destruction (by people or predators) and natural variations (food supply). The ORV pressure in the pinelands is intense because it lies within the most densely populated urban area in the United States. Although the number of snakes in the reference hibernacula varied over the years from 46 to 63, the percent of young in these hibernacula did not vary significantly over the 20 year period (21–29%). In contrast, the percent-young in the disturbed sites differed significantly in years without ORV disturbance (28%) compared to those with ORV disturbance (15 and 16%, P < 0.01). Further, there were no differences between the percent of young in the reference sites and those in the disturbed site in years without ORV disturbance. ORV disturbance ceased only with the creation of large dirt berms coupled with fences that could not be easily broken. These data indicate the importance of having detailed population data on pine snakes in hibernacula, on ORV use (or indications of such use), and of managing ORV use to protect sensitive populations. Maintenance of healthy pine snake populations in urban areas may require continued adaptive management.     

The importance of paleodunes as nesting habitat for Northern Pine Snakes (Pituophis melanoleucus melanoleucus): risk from off-road vehicles in the New Jersey Pine Barrens

Human development and disturbances can be determinants of population viability of some vertebrates in human-impacted ecosystems. The effects on the behavior and population dynamics of reptiles are not well-studied in urban environments. This paper examines the importance of pine forest clearings, openings, and paleodunes for nesting pine snakes (Pituophis melanoleucus melanoleucus) in the New Jersey Pinelands, and the risk to nesting females and offspring from off-road vehicles (ORV). In this ms we 1) develop a rating scale for ORV activity that can be modified for evaluating risk to other vertebrates, 2) compare general habitat features of nesting areas used in the early 1980s with those used in 2020, and 3) examine the fate of nesting areas used in the 1980s and the intensity of ORV use in both time periods. In 2020, nests were located at only 2 of the 10 nesting areas used in 1983 (20%), and only one of the 10 was a paleodune. In comparison, in 2020, 9 of 13 new nesting areas were on paleodunes (69%). In 1983, ORV activity on nesting areas ranged from very low to medium. In the intervening years development and ORV activity increased markedly, and snakes abandoned most areas by 2020. ORV activity in those sites still utilized for nesting increased to high and very high. In 2020, ORV activity ranged from very low (7%) to very high (19%) of the 42 nests. With increasing urban development, nesting pine snakes are using mainly paleodunes deep in the forest, and are exposed to high or very high ORV activity (43%), suggesting concern for viable snake populations in the wake of continued human activity and ORV use.