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Recent decline in New Hampshire's moose (Alces alces) population is attributed to sustained parasitism by winter ticks (Dermacentor albipictus) causing high calf mortality and reduced productivity. Location of larval winter ticks that infest moose is dictated by where adult female ticks drop from moose in April when moose preferentially forage in early regenerating forest in the northeastern United States. The primary objectives of this study were to: 1) measure and compare larval abundance in 2 types of regenerating forest (clear-cuts and partial harvest cuts), 2) measure and compare larval abundance on 2 transect types (random and high-use) within clear-cuts and partial harvests, and 3) identify the date and environmental characteristics associated with termination of larval questing. Larvae were collected on 50.5% of 589 transects; 57.5% of transects in clear-cuts and 44.3% in partial cuts. The average abundance ranged from 0.11-0.36 ticks/[m.sup.2] with abundance highest (P < 0.05) in partial cuts and on high-use transects in both cut types over a 9-week period; abundance was ~2 * higher during the principal 6-week questing period prior to the first snowfall. Abundance (collection rate) was stable until the onset of < 0[degrees]C and initial snow cover (~15 cm) in late October, after which collection rose temporarily on high-use transects in partial harvests during a brief warm-up. The higher abundance of winter ticks on high-use transects indicates that random sampling underestimates tick abundance and relative risk of infestation of moose. Calculating an annual index of infestation of winter ticks on moose is theoretically possible by integrating 3 factors: the infestation of harvested moose in October, the length of the questing period, and assuming a stable collection rate during the questing period. ALCES VOL. 56: 1-13 (2020) Key Words: Alces alces, Dermacentor albipictus, forest habitat, infestation, moose, questing, tick abundance, winter ticks, The influence of winter ticks (Dermacentor albipictus) on population dynamics of moose (Alces alces) in the northeastern United States (northeast) is well documented (Musante et al. 2010, Bergeron et al. [...]

Snow urine samples collected in northern New Hampshire, USA were used to measure urea nitrogen (UN) and creatinine (C) content to develop ratios for tracking the nutritional restriction of individual moose (Alces alces) through winter (2014-2017), inclusive of the adult winter tick (Dermacentor albipictus) engorgement period. Samples (n = 215) were collected from 55 moose (38 calves, 17 cows) on a twice monthly schedule from late January through snowmelt or calf mortality (March - early April). Early winter UN:C ratios from cows, surviving calves, and calves that ultimately died from infestation of winter ticks were similar and reflected a normal winter diet low in protein. A heightened UN:C ratio (> 3.5 mg/dL) was measured in March which aligned with peak feeding by adult winter ticks, and presumably reflected accelerated protein deficit associated with blood loss. This increase was not observed population-wide despite shared habitat, occurring only in calves with mortal weight loss and anemia associated with heavy winter tick infestation. Measurement of UN:C ratios from snow urine samples proved an effective method to measure the temporal impact of winter tick infestation, and March samples can support other metrics used to estimate calf mortality. ALCES VOL. 55: 13-21 (2019) Key words: creatinine, epizootic, New Hampshire, moose, nutritional restriction, snow urine, urea nitrogen, winter ticks, New Hampshire has experienced at least 5 winter tick (Dermacentor albipictus) epizootics (> 50% calf mortality) in the last decade, an unprecedented rate of occurrence (Musante et al. 2010, Bergeron [...]

Moose (Alces alces) populations in northern New Hampshire and western Maine experienced 3 successive years of high winter tick infestations (epizootics) in 2014-2016 that resulted in late-winter calf mortality rates >70%. To assess productivity in these populations, we measured fecundity rates of yearling and adult cow moose, and neonatal and summer calf survival. Parturition, fecundity, and survival were measured via direct observation by stalking VHF and GPS radio-collared cows (n = 177) in May-August, 2014-2016. Calving rates for yearlings and adults averaged 0 and 57%, respectively; there was no twinning documented. Summer calf survival to August was high overall (83%), with 85% of the mortality occurring in the first week of life. Calving and twinning rates declined since last measured in New Hampshire in 2002-2005 and were below the North American average; conversely, summer survival of calves was considered normal. Given that optimal habitat has increased in the past 15 years in the study area that is dominated by commercial forestry, lower productivity is presumably related to the additive impacts of successive winter tick epizootics on year-round condition of cows. Key Words: Alces alces, calving, fecundity, Maine, neonate survival, New Hampshire, pregnancy, winter ticks, Many moose (Alces alces) populations along the southern edge of their North American range are declining, including in Minnesota, Manitoba, Nova Scotia, Vermont, New York, and New Hampshire (Murray et [...]

An isolate of the soil fungus Scopulariopsis brevicaulis was identified from the surface of female winter ticks (Dennacentor albipictus) collected from recently dead moose (Alces alces) calves in New Hampshire in the northeastern United States. It was the sole isolate, and it matched with 98% nucITS similarity (molecular systematics Blast match) to S. brevicaulis species from soil and other tick species. Inoculation of tick larvae and eggs with [10.sup.8] spores/mL + 0.05% Tween (aqueous inoculum) resulted in mortality, reduced survival time, and recovery of S. brevicaulis from within tick tissues. Rapid water loss and death from dehydration were the pathogenic consequences of the fungal infection. Three entomopathogenic fungal isolates from laboratory culture (Beauveria bassiana, B. caledonica, and Metarhizium anisopliae) inoculated concurrently at the same dose, were slightly less pathogenic to eggs than larvae of winter ticks. We conclude that S. brevicaulis imposes a limitation on the free-living stages of the winter tick population in specific environmental conditions, but commercial fungal treatments as used in local situations to control ticks, are impractical as a means of controlling winter tick density across moose habitats. Key words: Alces alces, Dermacentor albipictus, moose, pathogenic fungi, Scopulariopsis brevicaulis, survival, water balance, winter ticks, INTRODUCTION Winter ticks (Dermacentor albipictus) periodically cause high calf mortality in moose (Alces alces) populations in the northeastern United States and southern Canada due to numerous interactive stressors, including extreme [...]

ABSTRACT: Winter habitat use by moose (Alces alces) is typically comprised of regenerating forest and softwood cover in the northeastern United States, and globally, high winter densities are of concern [...]

ABSTRACT: Age, field-dressed body weight, and antler spread data collected from 11,566 harvested moose (Alces alces) were analyzed to assess whether temporal change has occurred in the physical characteristics of [...]

Many wildlife populations are experiencing a variety of environmental pressures due to the direct and indirect consequences of a changing climate. In the northeast, USA, moose Alces alcesare declining in large part because of the increasing parasitism by winter tick Dermacentor albipictus, facilitated by high host density and optimal environmental conditions. To test this hypothesis, and better understand the influence of this interaction on the stability of the regional population, we constructed a population viability model using data collected through comprehensive survival and productivity studies in 2002–2005 and 2014–2018 in northern New Hampshire. Years of heavy tick infestation (epizootics) saw a marked reduction in calf survival (< 50%), adult calving (< 60%), twinning rate (< 5%) and complete loss of yearling productivity. We conducted population viability analysis using VORTEX ver. 10.2 to model this moose population for 40 years using mean demographics from both time periods, including environmental variation measured in the field during winter tick epizootic (2002, 2014, 2015, 2016) and non-epizootic (2003, 2004, 2005, 2017) years. This exercise highlights the influence of winter tick infestation on the trajectory of the population with the potential for rapid population growth or decline depending on the frequency of epizootics. We suggest a shift in moose management strategy focused on lowering moose density, assuming continued influence of climate change on the host–parasite relationship.

We report that larvae of the winter tick Dermacentor albipictus, the only stage that will quest for a host, can tolerate short-term cold shock down to −25°C and short-term heat shock as high as 46°C. Unlike a three host-tick, larvae of D. albipictushave no preconditioning response to low or high temperature exposure by rapid cold hardening (RCH) or heat hardening, and poor ability to acclimate to low and high temperature extremes. Thermal tolerance limits were not improved as the result of larval clustering, and there was only a minimal effect due to changes in photoperiod. These larvae are freeze intolerant and die at higher temperatures (−5 to −10°C) from contact with ice by inoculative freezing. In absence of cold-associated resistance mechanisms, winter survival requires that larvae procure a host before the first snow cover. Their low and high temperature tolerance, however, is a key survival element that adapts them for off-host periods during summer, which in the arctic could allow for northern expansion.

ABSTRACT Effective management of white-tailed deer ( Odocoileus virginianus) populations requires reliable estimates of demographic parameters. New Hampshire's deer population has increased substantially since the 1980s, while recruitment rates based on indices from harvested deer have steadily declined since the mid-1990s. To better understand the reasons for such decline, we assessed the current reproductive attributes of New Hampshire's deer herd through measurement of ovulation rate, pregnancy rate, and fetal counts from winter mortalities during 2011-2013 and compared these data with similar data collected in New Hampshire, USA, during 1972-1987. Pregnancy rates were 97% and 100% in the adult and yearling age classes, respectively, but few (8%) fawns bred. All pregnant fawns carried single fetuses, while yearlings averaged 1.72 fetuses and adults 1.95. Peak breeding for adults and yearlings occurred during the third week of November; fawns bred 4 weeks later. Pregnancy rate and fecundity of older deer were unchanged since the 1980s; fawn pregnancy rate declined but was always relatively low. Productivity of the population increased due to a greater proportion of adults in 2011-2013, suggesting that declining recruitment may be due to increased summer fawn mortality. Additional research is needed to provide more accurate estimates of recruitment and to identify the specific causes of summer fawn mortality; however, in New Hampshire and other northern deer populations limited by severe winters, lower recruitment rates may render local population goals unachievable. © 2015 The Wildlife Society. [ABSTRACT FROM AUTHOR]