Characteristics and dynamics of a regional moose Alces alces population in the northeastern United States

Abstract

Abundance indices suggested that the moose Alces alces population in northern New Hampshire was stable despite favourable habitat and conservative harvest. Causes and rates of mortality were unknown because moose reproduction and survival was unstudied in the region. Our study was designed to investigate the dynamics of the regional population in 2002-2005. A total of 92 moose (33 cows and 59 calves) were captured and fitted with radio-collars (VHF¼83, GPS¼ 9). Parturition ranged from 8 May to 13 July (median ¼ 19 May) with 78% of births occurring during 13-27 May. Calving rate of yearlings and adults (. 2 years old) averaged 30 and 85%, respectively; twinning rate was 11%. Analysis of reproductive data from harvested cows (1988-2004) indicated that the average weight of adult cows increased but their corpora lutea count declined from ; 1.4 to 1.2/cow. Both ovulation rate and average weight of yearling cows declined about 25 and 4%, respectively. There were 39 mortalities (49% calves) with winterkill/parasite (41%), vehicle collision (26%) and hunting (18%) as the leading causes. Major sources of mortality of radio-marked cows were human-related; survival was 0.87. Annual calf survival was 0.45. Unmarked calf (0-2 months of age) survival was 0.71 with 76% of mortality in the first month of life. Radio-marked calves (; 7-12 months of age) had a survival rate of 0.67; 74% of the mortality was winterkill/parasite related. Calf mortality was concentrated (88%) in late winter-early spring. The unseasonably warm and snowless fall in 2001 probably favoured high tick transmission and increased tick loads on moose that resulted in high calf mortality (0.51) and measurable cow mortality (10%) in mild winter-spring 2002. Documentation of substantial tick-related mortality of radio-marked moose calves was unique to this study. The stability of the moose population probably reflects the variation in annual recruitment and lower fecundity of yearling cows associated with heavy infestations and epizootics of winter tick. Given that fertility, calving rate and body condition of adult cows, and summer calf survival are annually high, the population should recover from tick epizootics that periodically inhibit population growth.

Assessment of the status and viability of a population of moose (Alces alces) at its southern range limit in Ontario

“…Survival rates for female moose were comparable with those reported for other expanding and (or) increasing populations (e.g., Musante et al 2010), and the increase in moose mortality during late winter was due to a predictable spike in deaths from starvation. Notably, late-winter starvation occurs in many moose populations across the range, even those not subject to marked food restriction (e.g., Modafferi and Becker 1997;Van Ballenberghe and Ballard 1998).…”

“…For example, our area receives 40-80 cm of snow during winter, which exceeds the critical threshold for deer (DelGiudice et al 2002); this snow regime forces deer to yard communally in restricted locations during December-March and could limit spatial overlap with moose during periods when deer are shedding parasites (see Lankester 2010). Similar snow conditions also occur in other areas where moose populations are increasing (e.g., Musante et al 2010), whereas shallower snow is characteristic of some (e.g., Murray et al 2006) but not all (e.g., Lenarz et al 2008) regions where moose are declining. A more extensive analysis should reveal whether stationary or increasing moose populations in the southern range are characterized by deer populations that are either naturally low or snow-restricted in their distribution.…”

“…These results confirm that the reported decline of moose across much of its southern range (Lankester 2010) currently does not relate to southern Ontario. Because other southern moose populations also are increasing and expanding their range (see Foster et al 2002;Darimont et al 2005;Musante et al 2010), our collective results invite an assessment of why numeric decline and range loss are occurring among select populations and whether those that currently are viable likely will experience future reduction.…”

“…Southern moose also show signs of chronic malnutrition and have unusually wide-ranging movements, providing additional evidence of distress ). Yet, population decline is not ubiquitous across the southern range, and recent recovery or expansion of moose into new areas in western Canada and the northeastern United States (Foster et al 2002;Darimont et al 2005;Musante et al 2010) casts doubt on the veracity, or at least the generality, of the predicted northward recession of moose range (see Thompson et al 1998;Murray et al 2006;Varrin et al 2007). In fact, the paradoxical range expansion-contraction pattern in moose (Laliberte and Ripple 2004) challenges our basic understanding of how this species responds to environmental change, thereby limiting our ability to predict future change in population status and distribution consequent to climate effects.…”

First Reports of Pseudorabies and Winter Ticks (Dermacentor albipictus) Associated with an Emerging Feral Swine (Sus scrofa) Population in New Hampshire

“…comm.). In a recent study in New Hampshire, winter tick infestation was responsible for 41% of radio-collared moose mortality with calves representing 88% of deaths (Musante et al 2010). Feral swine appear to influence the distribution of multiple tick species by transporting them to new areas, which increases the probability of pathogen transmission (Sanders 2011) and feral swine may also serve as an additional host in the maintenance and distribution of some parasites, including winter ticks.…”