Habitat Components of Clear-Cut Areas for Snowshoe Hares in Michigan

Conroy, Michael J.; Gysel, Leslie W.; Dudderar, Glenn R.

doi:10.2307/3808747

Cited by 44 publications

(27 citation statements)

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“…Relatively few samples (approximately 20) are necessary to detect a 40% or greater difference among habitat units. Our results are similar to Conroy et al (1979), who, using Wight's (1938) density board to estimate vertical structure of vegetation in clear-cut areas for snowshoe hare (Lepus americanus L.) habitat, determined that 20 plots/community was sufficient to detect a 40% mean difference in understory cover. However, we recommend that all researchers evaluate power of their tests, especially if no differences were found (The Wildlife Society 1995).…”

Section: Sample Size Considerationssupporting

confidence: 89%

Sample size, power, and analytical considerations for vertical structure data from profile boards in wetland vegetation

et al. 1998

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Profile boards are commonly used to estimate vertical cover of herbaceous vegetation in the evaluation of wildlife habitat. However, data from this technique are seldom collected or analyzed in a consistent manner. Therefore, we investigated and evaluated methods of profile-board data collection and analysis using univariate and multivariate techniques. We collected 11,056 samples of vertical-structure data (percent cover) at 2,764 points in 8 playa wetlands in the Southern High Plains of Texas during 1989 and 1990, Visual obstruction data were collected along 5 transects in each playa, with 4 subsamples taken at each point. Data from strata of a profile board rarely followed a normal distribution. Observations among strata were correlated. initial analysis with a multivariate technique to simultaneously test data from all strata is recommended to control experiment-wise error rates. Only when a significant effect is determined in initial analyses should other multivariate techniques or univariate analyses follow to assess differences. Collecting > 1 observation per sampling point (i.e., subsanapling) did not affect analysis and is only necessary when subsamples are not con-elated. Sampling should be stratified throughout a habitat to account for structural variation within a habitat. Transforming percent cover into scores reduced differences among habitat units and may result in a misrepresentation of the data due to the potential for an indication of plant cover despite no vegetation occurring. When estimating a population mean, we recommend a minimum sample size of 20 points/habitat unit and arcsine transforming percent data to achieve acceptable type 1 error rates. When comparing 2 or more habitats or experimental treatments, aresine transformation of percent data is not necessary. General procedural recommendations for use of profile board are (1) use a board that is relative in height and strata size to vegetation/ animal of interest, (2) use equally spaced strata to avoid biasing results to certain stratum, (3) determine the distance from which to read the board by calculating the distance that results in the most variation in cover values, and (4) use one observer or randomize observers among expcrimental units.

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Section: Sample Size Considerationssupporting

confidence: 89%

Sample size, power, and analytical considerations for vertical structure data from profile boards in wetland vegetation

et al. 1998

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“…Data compiled by Oswald and Brown (1990) suggest that sufficient stem densities (148 stems/dam 2 with 89% cover) and heights of <1 m develop within 5 years after a wildfire in southwestern Yukon. The presence of deadfall, however, might encourage early use of post-fire stands if vegetation does not provided sufficient cover (Conroy et al 1979). The fact that a high pellet density occurred in the youngest stand in the chro nosequence (402 pellets/dam 2 , stand 8 years old) suggests that peak Snowshoe Hare abundance may occur within a few years after a fire; this is earlier than reported in other studies (>15 years -e.g., Monthey 1986; Thompson et al 1989;Paragi et al 1997;Newbury and Simon 2005;Jacqmain et al 2007;Hodson et al 2011).…”

mentioning

confidence: 71%

“…Deadfall above the forest floor likely serves as hiding cover (Hodges 1998;Andruskiw 2003;Berg et al 2012), possibly as thermal cover in winter (Conroy et al 1979;Roy et al 1995), and likely facilitates safer movement by Snowshoe Hares through the local vegetation. Not all young forest stands contained deadfall, possibly due to the pre-fire characteristics of a stand or the intensity of local burning, nor were older stands devoid of the material.…”

Section: Discussionmentioning

confidence: 99%

Stand-level Attributes of Snowshoe Hare (<em>Lepus americanus</em>) Habitat in a Post-Fire Trembling Aspen (<em>Populus tremuloides</em>) Chronosequence in Central Yukon

Strong¹,

Jung

2013

Can Field Nat

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. Forty stand-level compositional and structural variables were assessed as possible predictors of Snowshoe Hare pellet densities. Multidimensional scaling was used to identify variables (n = 10) that were most strongly related to pellet densities and was followed by multiple regression. Canopy cover of Trembling Aspen <50 cm tall and Western White Spruce ≤1 m tall, and deadfall depth, in combination, were the best estimators of Snowshoe Hare pellet densities among stands in the chronosequence (P <0.001, 64.5% variance explained). Although Trembling Aspen <50 cm tall explained the most variance, its canopy cover did not exceed 10%. More Trembling Aspen cover <50 cm tall and greater deadfall depths within the chronosequence were associated with stands ≤20 years old. Peak Snowshoe Hare use occurred in early (≤20 years old) rather than mid-successional (21-120 years old) stands, contrary to use patterns reported elsewhere. The lack of tall understory shrubs likely limited the use of mid-successional stands.

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“…Patch size and isolation contribute to population decline at a low proportion of habitat, and this phenomenon could be incorporated in a future study to investigate fragmentation effects on cyclicity in metapopulations. Additionally, habitat interspersion and increased edge has been shown to benefit prey when they are able to dart from the edges of safer habitat into low cover but high quality food habitat, then quickly return to refuge habitat (Conroy et al 1979, Liu et al 2014). This trade-off between increased diversity of food resources and increased predation risk could also be investigated with this framework, similar to Liu et al (2014).…”

Section: Future Modelingmentioning

confidence: 99%

Theoretical impacts of habitat loss and generalist predation on predator–prey cycles

Vitense

Wirsing

Tyson

et al. 2016

Ecological Modelling

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I used a reaction-diffusion-advection framework to investigate the relative and combined damping impacts of generalist predation and habitat loss with reaction terms taken from the May and Rosenzweig-MacArthur models. The models were parameterized using data from snowshoe hare and Canada lynx field studies to generate similar cyclic dynamics in the center of a single patch in the absence of generalist predation. I found that generalist predation has strong stabilizing effects for both models and may represent a threat to the persistence of specialized predators. The magnitude of cycle damping due to habitat loss depends on movement rates and model choice, but ultimately results in the loss of cycles. Differences in model carrying capacity may explain differences in model sensitivity to habitat loss, and cycle amplitude may or may not decrease monotonically with habitat loss, depending on model choice. Elevated generalist predation rates at patch edges and in matrix habitat hasten cycle attenuation in situations that lead to increased prey exposure to generalists, including small patch size, higher movement rates into the matrix, and increased prey density at patch edges. Habitat disturbances may therefore have myriad consequences for cyclic systems depending in part on the nature of specialist predator-prey interactions and the extent to which the disturbances increase generalist access to prey. Field data that clarifies the relationships between habitat loss and fragmentation, generalist density and behavior, and cyclic activity would be invaluable in informing future modeling efforts.

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Habitat Components of Clear-Cut Areas for Snowshoe Hares in Michigan

Cited by 44 publications

References 0 publications

Sample size, power, and analytical considerations for vertical structure data from profile boards in wetland vegetation

Sample size, power, and analytical considerations for vertical structure data from profile boards in wetland vegetation

Stand-level Attributes of Snowshoe Hare (<em>Lepus americanus</em>) Habitat in a Post-Fire Trembling Aspen (<em>Populus tremuloides</em>) Chronosequence in Central Yukon

Theoretical impacts of habitat loss and generalist predation on predator–prey cycles

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