Clearcutting creates habitat for many species of early successional songbirds; however, little information is available on bird use of small forest openings created by group selection harvests. Group selection harvests are increasing on the White Mountain National Forest due to negative public response to clearcutting. The objective of this study was to determine if avian species richness and composition differ between clearcut and group selection openings, and between mature stands and the uncut portions of group selection stands. Point count surveys were conducted during the 1992 and 1993 breeding seasons within six study blocks in the White Mountain National Forest, NH. Each block consisted of a clearcut stand, a group selection stand and a mature stand. Species richness per stand was signi®cantly higher in clearcut openings (p 0.010) than in group selection openings. Forested areas surrounding group selection openings were similar to mature stands in species richness (p 0.848) and composition. Our data suggest that, relative to avian use, the group selection system does not provide habitat similar to that created by clearcutting in extensive northern hardwood stands. The group selection system appears to retain much of the mature forest bird community while providing for a limited number of early successional bird species. Gradual replacement of clearcutting with group selection harvests could result in reduced avian diversity across large forested tracts. #
Populations within ecological communities constantly fluctuate due to a multitude of interactions that can be influenced by climate change. Moose (Alces alces (Linnaeus, 1758)) populations in northern New Hampshire and western Maine, subunits of the largest regional moose population in the continental United States, are suspected to be declining due to increasing frequency of winter tick (Dermacentor albipictus Packard, 1869) epizootics that cause >50% late-winter mortality of 9- to 12-month-old calves. To investigate this hypothesis, we collected general health measurements of calves captured at two study sites in January 2014–2016 and subsequently performed field necropsies and histologic examination of tissues of those radio-marked calves that died during winter and spring. At capture, calves (n = 179) were in normal (66%) and thin (32%) physical condition with high infestations of winter ticks. Most (88%) mortalities (n = 125) were associated with moderate to severe infestations of winter ticks. Gross necropsies and histologic examination found high tick infestations, emaciation, anemia, and endoparasitism; lungworm (species of the genus Dictyocaulus Railliet and Henry, 1907) was also found in most (87%) calves. Three consecutive years (2014–2016) of winter tick epizootics is unprecedented in the region, rare in North America, and arguably reflects a host–parasite relationship strongly influenced by climate change at the southern fringe of moose habitat.
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.
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