Roy V. Rea

Modifying roadside vegetation management practices to reduce vehicular collisions with moose Alces alces

Vegetation management practices currently used within transportation corridors are primarily aimed at minimising encroaching shrub and tree growth in order to increase driver visibility and road safety. Such practices create prime foraging habitat for ungulates such as moose Alces alces by inhibiting forest succession and maintaining early seral shrub communities. Increased foraging activity within the corridor increases the likelihood of encounters between moose and motorists. Moose-related vehicular collisions are costly in terms of material damage claims and have significant negative impacts on public safety and moose populations in many parts of their range. Although several countermeasures have been developed in an attempt to reduce the frequency of these collisions, few have proven effective and even fewer have taken into consideration possible links between roadside vegetation management, the quality of browse regenerating from cut vegetation, and how moose use browse within the transportation corridor. To better understand these relationships, I reviewed the literature on ungulate-related vehicular collisions in combination with literature on plant response to mechanical damage. Many authors recognise the need to reduce the attractiveness of vegetation growing within transportation corridors. To date, diversionary feeding, forage repellents, establishment of unpalatable species and elimination of roadside brush have been used. Unfortunately, such techniques are only semi-effective or are not cost-efficient when applied across the landscape. It has long been recognised that the ability of plants to regenerate following mechanical damage is influenced by the timing of damage. Current research suggests that the quality of regenerating plant tissues for herbivores also depends on when plants are cut. Plants cut in the middle of the growing season produce regrowth that is high in nutritional value for at least two winters following brush-cutting as compared to plants cut at other times of the year, and uncut controls. Because roadside brush is generally cut during mid-summer, possible links between the quality of regenerated browse and increases in ungulate-related vehicular collisions during the autumn and winter should be elucidated. Based on this review, I recommend cutting brush early in the growing season and emphasize the need for collaborative long-term research to properly address this issue.

Road and Rail Side Vegetation Management Implications of Habitat Use by Moose Relative to Brush Cutting Season

Plants cut at different times produce resprouts that vary in their nutritional value relative to when they are cut. To determine how vegetation management in transportation (road and rail) corridors at different times of the year could influence browse quality in the years following cutting, and how this could potentially influence encounters between herbivores and vehicles, we undertook a 3-year study. In 2001, at a wildlife viewing area near Prince George, British Columbia, Canada, we established a control area and treatment areas where shrubs and trees that are used as food by moose (Alces alces) were cut at the beginning of June, July, August, September, and October. In the fall, moose were most often observed browsing the resprouts of plants cut in August (years 1 and 2 post-treatment) and September (year 3). Cumulative winter track counts were highest in the uncut control area in the years following cutting. Spring pellet counts revealed that most pellets were deposited in the uncut (years 1 and 2) and August-cut (year 3) areas during winter. With the exception of the first year after cutting, browse removal by moose was highest for plants cut later in the growing season. Overall, our findings suggest that following cutting, plants cut later in the year are selected more often by moose relative to those cut earlier. To reduce browse use of corridor vegetation in areas where concerns for moose-vehicle collisions exist, we recommend that vegetation maintenance activities be conducted in the early summer months of June and July.

Extent of Stem Dieback in Trembling Aspen (Populus Tremuloides) as an Indicator of Time-since Simulated Browsing

Abstract Simulated browsing treatments were imposed on an important browse species of the North American moose (Alces alces L.) to see if the development and extent of subsequent stem dieback in trembling aspen (Populus tremuloides Michx.) could be used to determine the time of browsing during the growing season. Two hundred naturally growing aspen saplings of similar size and form were randomly selected in a 20-ha area near the endowment lands of the University of Northern British Columbia, Prince George, British Columbia, Canada. Plants were randomly assigned to treatment categories so that the apical meristems of 50 plants each were assigned to a control or were clipped on one of the following dates 6 weeks apart: 1 June, 16 July, and 30 August 2005. The leader of each aspen was clipped and dieback was left to progress until the onset of winter dormancy. Our results showed that the earlier the simulated browsing occurs in the growing season, the greater the length of stem dieback, up to the maximum of the subapical axillary node below the point of clipping. The average rate at which dieback progressed varied between treatments and decreased throughout the growing season. Our results suggest that the ratio of the actual length of stem dieback to the overall length of stem between the clip point and the subapical axillary node serves as a good indicator for estimating the time at which aspen meristems have been browsed during the growing season.

Paper birch (Betula papyrifera) shoot selection by moose (Alces alces) following a forest-cleaning experiment

Abstract In order to maximize food intake per harvesting effort and minimize energy expenditures required to move between feeding patches in nature, herbivores such as moose (Alces alces L.) generally select large plant shoots when browsing in winter. To determine moose preferences for shoots of different morphologies, an experiment was conducted in northern British Columbia in which shoots from birches cut at different times of the growing season were fed in 2 consecutive years to eight human-habituated moose in cafeteria-style feeding trials. The results indicate that moose preferred smaller winter shoots of birches regardless of when the parent plant was cut and also appeared to reject larger shoots containing sylleptic branches. It is argued that the preferences for smaller shoots by moose detected in these trials should be observable under natural conditions, but are generally only supported by literature from some parts of Scandinavia. The findings underscore the importance that factors such as mouth filling per harvesting effort, snow depth and consistency, predators and browse patch distribution must have on foraging decisions made by moose while browsing in the wild. Implications of the findings include the significance of cutting time on the size of shoots produced by birch after cutting, how this affects moose browsing birch and, subsequently, how managers can theoretically use cutting time as a tool in forest cleaning operations to direct the foraging efforts of moose towards or away from forest plantations.

Application of a species distribution model to identify and manage bear den habitat in central British Columbia, Canada

Several mammals have adapted to harsh winter conditions by adopting hibernation strategies that enable them to survive periods of unfavourable environmental conditions. At northern latitudes, black and brown bears can be in a state of hibernation for up to seven months. As a result of this prolonged occupation of one small space, bears can be vulnerable to environmental and human caused disturbances. In this study, we developed a predictive model that identifies potential den habitat for black bears that can assist with management planning for industrial land development activities. We identified 40 dens (17 excavated in soil and 23 natural rock cavities) and used fine-scale information to determine how dens were positioned in forest stands. We found that bears denned in areas on mid to upper slope positions and that soil dens were located mainly in clay-loam soil complexes while rock cavity dens were either caves or cavities in boulder piles. Den location was distant from portions of the study area with relatively high road density. We then used resource selection functions to predict where bear dens might be located on the landscape. When applied to the GIS data, the averaged coefficients suggested that 3.1% of the study area had a high suitability ranking as den habitat while 9.1%, 14.6%, and 73.2% had mid, low, and limited suitability, respectively. In our study area, habitat for den sites is reasonably predictable and should be considered during the planning of industrial activities.

Characterizing Moose–Vehicle Collision Hotspots in Northern British Columbia

Abstract To have a better understanding of the ecological factors that may contribute to moose Alces alces and vehicle collisions in northern British Columbia, we analyzed Wildlife Accident Reporti...

Differential selection of North American and Scandinavian conifer browse by northwestern moose (Alces alces andersoni) in winter

Scandinavian moose (Alces alces) eat Scots pine (Pinus sylvestris) in winter. Although North American moose are known to eat conifers such as true firs (Abies spp.) in winter, substantial consumption of pine by moose in North America has not been documented. Here, we document short-term winter preferences of human-habituated northwestern moose (Alces alces andersoni) for branches of mature North American and European conifer species as determined by a cafeteria-style feeding trial. Moose selected for species such as Douglas fir (Pseudotsuga menziesii; from which they took the smallest bite diameters) while avoiding species such as lodgepole pine (Pinus contorta; from which they took the largest bites) and hybrid white spruce (Picea glauca × engelmanii). The amount of species-specific biomass consumed by moose was negatively correlated with bite diameters taken from branches of those species and did not appear to be significantly influenced by differences in twig morphology between species. Our trial suggests that northwestern moose readily consume conifers in winter and, from the species we tested, prefer Douglas fir. While no clear preference existed between Scots pine and lodgepole pine, moose avoided lodgepole pine, but not Scots pine, relative to Douglas fir. Our trial suggests that northwestern moose are more likely to feed on the branches of Douglas fir than pine, which may be of interest to foresters managing conifers within the North American range of moose, particularly where Scots pine are being considered for planting.

The use of an orthotic casting foam as a track-plate medium for wildlife research and monitoring

Track plates are an inexpensive, non-intrusive and widely used wildlife monitoring tool. Almost all track-plate media are not suited for use during rainy conditions, because rain or heavy dews can distort tracks or render the medium ineffective for registering further animal visitations. Furthermore, available track-plate media may also produce tracks of varying quality and hard-surfaced media produce inaccurate two-dimensional imprints. We experimented with the utility of using Biofoam™, a phenolic foam used in orthotics, as a track-plate medium. Domestic animals were utilized to produce track imprints on track plates constructed of casting foam, coarse sand, fine sand, very fine sand and sooted aluminum. Resulting tracks were photographed and images were used in a questionnaire which was completed by expert wildlife trackers who rated the quality of the tracks. Tracks in the casting foam are three-dimensional, register claws, clearly depict all pads, accurately record shape and size, and convey very fine anatomical details. Track imprints on the casting foam were rated consistently better by experts than track imprints left on the other media. Field trials demonstrated that the casting foam and tracks in the casting foam can endure lengthy periods of inclement weather conditions in the field without being damaged or distorted. In summary, where three-dimensional, high-quality prints need to be recorded in variable field conditions, we recommend the use and further experimentation with track plates made of casting foam.

Factors influencing the use of willow and birch by moose in winter

We evaluated browsing patterns of moose during 37 individual feeding trials conducted over a 3-day period in winter in which hand-assembled, species-specific trials containing various densities of either willow (Salix scouleriana) or birch (Betula papyrifera) saplings were presented to human-habituated moose (Alces alces andersoni). At the trial (patch) level, the pre-trial weight of both willow and birch was the most important factor in explaining the amount of biomass eaten, the length of all shoot materials removed from saplings, and the amount of edible biomass left uneaten by moose. For willow, the number of days moose were fed saplings partially explained the average bite diameters and the amount of edible biomass left uneaten following trials. The position of the sapling within the feeding station helped to explain the shoot length removed by moose, while sapling density influenced the amount of edible willow biomass left uneaten. At the individual sapling level, the pre-trial weight of birch and willow was important in helping to explain the amount of biomass eaten and the amount of edible biomass left behind. In addition, sapling density influenced the amount of willow biomass eaten, and both sapling density and trial day helped to explain the amount of edible willow biomass left behind.

Initial Effects of Brush Cutting and Shoot Removal on Willow Browse Quality

Abstract We examined the initial effects of brush cutting (removal of all aboveground biomass), as well as clipping (removal of current annual shoots) and ungulate browsing (collectively referred to as shoot removal) on the morphology and nutrient quality of Scoulers willow (Salix scouleriana J. Barratt ex Hook.) for ungulates on sites 2 and 4 years after brush cutting. We specifically assessed changes in the biomass, tannin content, digestible energy, and digestible protein of shoots from brush-cut willows relative to shoots of uncut willows to determine how browse plants respond to this form of vegetation management. In winter, the resprouted current annual shoots of willows that had been brush cut were larger in mass and lower in digestible protein than shoots of uncut willows for at least 4 years after brush cutting. Shoots of brush-cut willows were also lower in tannin and digestible energy than the shoots of uncut plants for two winters after brush cutting. In the second winter after brush cutting, shoot biomass decreased and tannin content increased with increasing shoot removal during the previous winter. In the fourth winter after brush cutting, shoot mass increased and digestible energy decreased in shoots with greater shoot removal. Nutrient quality was otherwise unaffected by the amount of shoot removal during the previous winter. Because of the occasional importance of site effects in this study, we recommend that long-term studies maximize the number of sampled sites. Because brush cutting alters the quality of regenerating browse and can affect how ungulates utilize such browse for several years after brush cutting, we further recommend that forest vegetation managers consider potential impacts of brush cutting on ungulate winter range.