Moose Herd Perseveres

by: Mark Pulsifer
FALL 1995

When Europeans first settled Nova Scotia's coastline, moose were the largest member of the deer family. They shared the forests with one other deer species, the woodland caribou. White-tailed deer had been absent from this province for many years, returning in the latter part of the 19th century. For a brief time, all three deer species co-existed. However, by the early 1920s caribou disappeared from our woodlands and barrens because of 300 years of market hunting, poaching, and habitat loss.

Similar population pressures have affected moose herds throughout Nova Scotia, resulting in dramatically fluctuating population levels. Some of these declines were so severe that the Provincial Game Commissioner's Report of 1910 indicated that moose numbers had approached extinction twice since 1800. Even during the first half of the 20th century, moose numbers continued to fluctuate dramatically because of winter range conditions, herd size, and carrying capacity of the habitat.

Today's moose herd size appears to be stable and even increasing in areas such as the Cape Breton Highlands and west of Kejimkujik National Park. Traditional population strongholds, such as the Cobequid Hills and the Pictou-Antigonish Highlands, have experienced significant declines in moose numbers. Prior to and during these declines (throughout the 1960s and 1970s), moose numbers were high enough to support an annual moose hunt. Declining hunter success prompted the closure of the mainland hunt after 1981.

Estimates of winter moose populations in these areas suggest the herd size declined from an average of 0.46 moose/km2 during the 1960s to about 0.08 moose/km2 today. Reasons for the decline may reflect the combined effects of competition with white-tailed deer, habitat fragmentation through forest management, illegal hunting, and predation by black bears.

Foremost is the devastating effect P. tennuis, a commonly occurring parasitic worm in our provincial deer herd, has had on moose. Although this parasite is non-lethal in deer, it produces neurological symptoms in moose often referred to as "moose sickness" and usually leads to death. In Nova Scotia, the frequency of moose sickness and the relationship between deer and moose numbers has been recognized for some time. Since the mid-1930s, game officials and biologists have observed moose numbers declining when deer numbers are high, and increasing when deer populations drop. During the late 1970s and early 1980s, when the provincial deer herd was building to an all time high, two distinct observations were made. As deer numbers increased, so did the number of moose showing signs of brainworm. Second, as deer number increased throughout this period, moose numbers appeared to decline significantly. This relationship has not been rigorously tested, however evidence suggests a need for further investigation

Habitat fragmentation through forest management has at times been a mixed blessing for moose populations. Forest management can enhance moose habitat by providing a scattering of covers for calving, escape, and thermo-regulation, as well as creating abundant browse. Past forest management plans seldom provided these important habitat elements unless their need had been previously identified. Instead, it was assumed there was adequate habitat "over the hill" and inoperable areas would accommodate moose by default. While this may be true in some instances, it is not always the case.

Today, forest management on Crown and private lands is placing greater emphasis on integrated resource management (IRM). This process accounts for wildlife species distribution and habitat needs, as well as for the distribution of merchantable timber, particularly at the landscape level.

One negative habitat change resulting from forest management is the network of roads that dissect the landscape. These roads not only increase the amount of forest edge that favours white-tailed deer, they also provide easy access into areas where moose feeding in open regenerating tracts are highly visible and more vulnerable to hunting. This does not explain widespread declines in moose populations over large areas. However, in localized high-access areas, where moose numbers are already low, increases in herd size may be offset by unregulated hunting. This relationship may be supported further when we consider that in nearly all areas where moose numbers are relatively high, accessibility by road is seasonally restricted or extremely difficult because of the terrain.

The role predation plays in regulating moose numbers in Nova Scotia is presently unknown. In many areas where moose occur, their numbers are regulated by wolves. Although records show that Nova Scotia has not had wolves since the 1840s, predation by black bears is a possibility. Black bears have been identified in other areas as major predators of moose calves up to 45 days of age, often accounting for a significant number of young animals. At present, bear harvest records and nuisance bear reports indicate that bears are abundant throughout many areas of Nova Scotia. If the impact of black bear predation on moose calves is similar to other jurisdictions, herd growth in areas of low and scattered moose numbers may be restricted.

Moose numbers are generally low on the mainland, but the same cannot be said for the Cape Breton Highlands. Following the introduction of 18 moose from Alberta in 1948 and 1949, the herd continued to grow steadily and unnoticed because of poor accessibility. The size of the moose herd and its potential was realized in the late 1970s when road construction to assess and salvage wood damaged by the spruce budworm was carried out. today, moose occur throughout the Highlands with little competition from deer. Winter comes early and stays late, producing snow several metres deep that forces deer to seek lower ground. This limits the chances of moose becoming infected with P. tennuis. Moose densities in this area range from 1.0/km2 in the south to 2.8/km2 in the north and hunter success has averaged 78 percent since the annual lottery hunt began in 1986. If these statistics are any indication, the Cape Breton herd appears to be healthy and relatively stable.

The future for moose on the mainland is less certain. With current deer numbers relatively low, moose densities may increase if other mortality factors do not negate recruitment. If history proves right, Nova Scotia cannot support high numbers of both moose and deer on the same range. while mainland moose will unlikely disappear completely, the likelihood that populations will return to levels similar to the 1960s may be remote as long as our climate, land use patterns, and management strategies favour white-tailed deer.