FINAL REPORT ON WILDLIFE MONITORING – HIGHWAY 7 FENCE PROJECT 2007-2012
Graham Forbes, PhD - 2012
Organization: NB Cooperative Fish and Wildlife Research Unit, University of New Brunswick
Location: New Brunswick
The objective of the project is to determine if the 27.6 km-long fence paralleling Highway 7 on Canadian Forces Base Gagetown will have a significant negative effect on large wildlife species, mainly moose and white-tailed deer.
The fence contains four underpasses designed to facilitate movement of animals. The fence was completed in October, 2008. Pre-fence movement data was collected in winter 2007/2008, spring 2008, summer 2008. These data are treated as a baseline of movement before the fence was constructed. Data collected in fall 2008 and since then represent the amount of movement after construction. A combination of two methods for documenting movement were used; tracks, and cameras. The core of the data was derived from tracks. The baseline data set are tracks recorded along the length of the fence (and 6 km beyond each end) for a minimum of three times during each of four seasons. Once the fence was established, these data were compared to track surveys conducted at the underpasses, and in the 6 km sections at the ends of the fence. The survey at the ends of the fence was done in order to determine if animals are moving around the ends; the movement at this larger scale may be sufficient to offset any decreased crossing along the fence. In December 2008, cameras were placed in the underpasses. This method supplements the track data; cameras were impractical for measuring movement over the 30 km of road before the fence was built. The road was sampled 3-5 times per season, with each sampling period representing 36 hours of fresh tracks.
The use of the underpasses was monitored for three years after fence construction. Camera and track data indicate that all large mammal species use the underpasses. Coyote and black bear do not appear to be limited by the fence or underpasses and receive limited discussion in the report. For moose, the amount of crossing after fence construction continues to be significantly lower than pre-construction crossing levels. In a comparison of 36 hour survey periods before fence construction versus 36 hr survey periods in the underpasses, average number of moose crossing in underpasses is about half of levels before the fence was built. Deer use is lower after fence construction but is similar in some seasons of some years, and because deer are crossing more at the end of the fence, the amount of crossing over the larger study area is similar t levels before the fence was built. There is evidence of increased use of the underpasses with time; there has been increases of 89% and 69% for moose and deer in first year after the fence compared to the third year, respectively.
The fence continues to limit the amount of moose crossing the highway. However, the amount of crossing suggests that it is enough to offset concerns over potential population or genetic impacts of creating isolated populations on either side of a fence. A total of 56 crossings in the underpasses by moose were recorded, and moose used all 4 underpasses across the length of the fence. Deer are crossing the highway at levels similar to levels before the fence was constructed. Also, the increasing use of the underpasses suggests the gap will narrow between amount of movement before and after fence construction. In conclusion, the underpasses along Highway 7 appear to not be a negative impact on the viability or distribution of moose or deer.
Document Type: mitigation monitoring results
Project Type: underpass
Infrastructure Asset: existing roadway