Forest-Fire Regime: The Missing Link to Understand Snowshoe Hare Population Fluctuations?

We tested the hypothesis that helminth parasitism is demographically significant to a noncyclic population of snowshoe hares (Lepus americanus) near the species' geographic boundary in central Wisconsin (U.S.A.). During November 1988 to December 1991, we injected 93 individuals (≥760 g, aged ≥2 months) with anthelmintics: Ivermectin for nematode and Droncit for cestode infections. We injected 98 control hares with propylene glycol, the common vehicle for both drugs. All treated and control hares were radio-collared with mortality-sensing transmitters and monitored daily to weekly from the ground or air. Prevalence and intensity of lungworms (Protostrongylus boughtoni), intestinal worms (Nematodirus triangularis), and stomach worms (Obeliscoides cuniculi) were markedly reduced by Ivermectin treatment. No other nematodes were found to be present. Treatment with Droncit to remove intestinal cestodes was apparently unnecessary, as prevalence among necropsied untreated hares and controls was just 10%. We compared body-condition indices (mass changes, response to trap stress, and bone-marrow fat), reproduction (pregnancy rate and litter size), home-range sizes, and time-specific survival rates of anthelmintic-treated versus control hares. None of these demographic variables differed significantly between treated and control cohorts, nor was there any evidence that parasitism increased the risk of death from predation, which was the proximate cause of 96% of all natural mortalities. We conclude that helminth parasitism played no detectable role in the dynamics of this Wisconsin snowshoe hare population.

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Influence of forest herbicide on snowshoe hare population dynamics: reproduction, growth, and survival

Canadian Journal of Forest Research ◽

10.1139/x26-012 ◽

1996 ◽

Vol 26 (1) ◽

pp. 112-119 ◽

Cited By ~ 3

Author(s):

Thomas P. Sullivan

Keyword(s):

Body Mass ◽

Demographic Parameters ◽

Snowshoe Hare ◽

Growth And Survival ◽

Physiological Processes ◽

Adult Females ◽

Breeding Condition ◽

Glyphosate Herbicide ◽

Hare Population ◽

Treatment Population

This study was designed to assess the influence of forest applications of glyphosate herbicide on reproduction, growth, and survival in snowshoe hare (Lepusamericanus Erxleben) populations in control (reference) and treatment habitats near Prince George, B.C. Proportion of adult hares in breeding condition and number of successful pregnancies showed no consistent differences between control and treatment populations. Recruitment of hares was generally similar except for significantly more juvenile females entering the control than treatment population at one study area. At a second study area, total recruitment was significantly higher in the treatment than control population for both sexes in 1990 and for adult females in 1991, the 2 post-treatment years. There was little difference in survival of hares between control and treatment populations. Lack of significant differences in mean body mass and growth rates suggested that this herbicide treatment had little or no effect on metabolic or general physiological processes in the development of young hares. Similar profiles of body mass distribution between control and treatment populations indicated that comparable levels of biomass of hares were available as prey for predators. Use of this forest herbicide did not measurably affect demographic parameters of snowshoe hare populations.

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Demographic Parameters of a Snowshoe Hare Population

Journal of Wildlife Management ◽

10.2307/3799557 ◽

1968 ◽

Vol 32 (4) ◽

pp. 812 ◽

Cited By ~ 33

Author(s):

E. Charles Meslow ◽

Lloyd B. Keith

Keyword(s):

Demographic Parameters ◽

Snowshoe Hare ◽

Hare Population

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Reproductive change in the 10-year cycle of snowshoe hares

Canadian Journal of Zoology ◽

10.1139/z79-044 ◽

1979 ◽

Vol 57 (2) ◽

pp. 375-390 ◽

Cited By ~ 50

Author(s):

John R. Cary ◽

Lloyd B. Keith

Keyword(s):

Pregnancy Rate ◽

Litter Size ◽

Weight Change ◽

Ovulation Rate ◽

Population Cycle ◽

Snowshoe Hare ◽

Cyclic Variation ◽

Reproductive Parameters ◽

Snowshoe Hares ◽

Hare Population

Reproduction was monitored during a 16-year study of snowshoe hare (Lepus americanus) populations near Rochester, Alberta. Pregnancy rate, ovulation rate, and litter size changed markedly between successive litters within the breeding season; these parameters were thus further categorized by litter in our analyses. Most reproductive components varied significantly between years; a significant '10-year' periodicity was the dominant source of this variation. The cyclic fluctuations of reproductive parameters were broadly synchronous and tended to precede the population cycle by about 3 years, thereby producing a range in potential natality annually of 7.5 to 17.9 young per female. The year-to-year variability of pregnancy rate, ovulation rate, and litter size was markedly larger in the later litters than in the early ones. Paunched weight, mean age, incidence of endoparasites, liver and spleen weights, and midwinter-to-spring weight change also possessed significant 10-year cycles; paunched weight cycled directly with the hare population, but the others cycled either directly with or counter to reproduction. We believe that the correspondence between midwinter-to-spring weight change and reproduction implicates winter nutrition as the primary cause of the cyclic variation. Onset of spring accounted for a significant amount of variability in onset of breeding, adding to that due to the periodic change.

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Spatial and Temporal Analysis of El Niño Impact on Land and Forest Fire in Kalimantan and Sumatra

Agromet ◽

10.29244/j.agromet.35.1.1-10 ◽

2021 ◽

Vol 35 (1) ◽

pp. 1-10

Author(s):

Sri Nurdiati ◽

Ardhasena Sopaheluwakan ◽

Pandu Septiawan

Keyword(s):

Forest Fire ◽

Forest Fires ◽

El Niño ◽

Fire Regime ◽

El Nino ◽

Function Analysis ◽

Spatial And Temporal Patterns ◽

El Niño Event ◽

Dry Spell ◽

The Impact

Land and forest fires in Kalimantan and Sumatra, Indonesia occurred annually at different magnitude and duration. Climate and sea interaction, like El Niño, influences the severity of dry seasons preceding the fires. However, research on the influence of El Niño intensity to fire regime in Kalimantan and Sumatra is limited. Therefore, this study aims to analyze the spatial and temporal patterns of the effects of El Niño intensity on land and forest fires in fire-prone provinces in Indonesia. Here, we applied the empirical orthogonal function analysis based on singular value decomposition to determine the dominant patterns of hotspots and rainfall data that evolve spatially and temporally. For analysis, the study required the following data: fire hotspots, dry-spell, and rainfall for period 2001-2019. This study revealed that El Niño intensity had a different impacts for each province. Generally, El Niño will influence the severity of forest fire events in Indonesia. However, we found that the impact of El Niño intensity varied for Kalimantan, South Sumatra, and Riau Province. Kalimantan was the most sensitive province to the El Niño event. The duration and number of hotspots in Kalimantan increased significantly even in moderate El Niño event. This was different for South Sumatra, where the duration and number of hotspots only increased significantly when a strong El Niño event occurred.

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Das Konzept «Waldbrand 2020» des Kantons Tessin

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2019.0242 ◽

2019 ◽

Vol 170 (5) ◽

pp. 242-250

Author(s):

Aron Ghiringhelli ◽

Gianni Boris Pezzatti ◽

Marco Conedera

Keyword(s):

Forest Fire ◽

Forest Fires ◽

Forest Restoration ◽

Fire Regime ◽

Forest Service ◽

Management Approach ◽

Fire Control ◽

Burnt Area ◽

Forest Protection ◽

Forest Fire Management

The “forest fire 2020” program of Canton Ticino The Canton of Ticino has a long-lasting experience in facing forest fires. As a result, a tradition in forest fire documentation and analysis exists and the forest fire management approach is continuously reviewed and improved with the aim to preserve the forest protection functions and to keep the mountain areas safe for the inhabitants. The fire regime has been reduced in Ticino since the seventies of last century thanks to improvement of the firefighting organization and fire control techniques (e.g. systematic use of helicopters for the aerial fire control) and the possibility of declaring a total fire ban in the open. However the demand in terms of protection of human lives and goods of the modern society is raising and as consequence of the climate change fire risk may increase in the future. For this reason two years ago the forest service of Canton Ticino developed the “forest fire 2020” program, in collaboration with the cantonal fire brigades association and the federal research Institute WSL. The program consists of four interdependent activity modules, which are 1) prevention, 2) organizational and technical measures, 3) firefighting and control, 4) burnt area restoration. The forest service is responsible for the fire-danger rating, the fire-ban release, the mentoring of local authorities in forest management questions and for planning pre-suppression facilities (e.g. water points for helicopters). It is also responsible for defining the mission rules for aerial firefighting, for collecting the data for the statistics, and for planning the post-fire forest restoration measures. The fire brigades are in charge of the firefighting tasks, by first intervening with the urban fire brigades and in case of need requiring the support of specialized forest-fire brigades. During the firefighting actions the forest service takes a consulting role. The first two years of implementation confirmed the suitability of the “forest fire 2020” program. Potential improvements have been however detected and are under implementation, such as the completion of the pre-suppression infrastructures, a better coordination between aerial and terrestrial firefighting and the strengthening of the specialized forest-fire brigades.

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