Martes Americana Research Articles

Snow‐tracking and GIS: using multiple species‐environment models to determine optimal wildlife crossing sites and evaluate highway mitigation plans on the Trans‐Canada Highway

Snow‐tracking data were collected for cougars ( Felis concolor), lynx ( Lynx canadensis), martens (Martes americana) and wolves (Canis lupus) and combined with remotely sensed imagery in a geographic information system (GIS) to identify wildlife crossing sites on the Trans‐Canada Highway in Banff National Park, Alberta. We used logistic regression to assess the dependent (species presence/absence) relative to measures of topography and vegetation. The exponent form of each logistic regression equation was used to predict crossing sites in a GIS, which were then contrasted with mitigation sites proposed by Parks Canada. We found that: (1) cougars were influenced positively by normalized difference vegetation index (NDVI); negatively by northness and distance to ruggedness, (2) lynx were influenced positively by wetness, greenness, rugged terrain, eastness and distance to rugged terrain; negatively by slope, (3) martens were related positively to wetness, elevation, eastness, and distance to rugged terrain; negatively to northness, (4) wolves were influenced positively by distance to ruggedness; negatively by brightness, elevation, eastness and terrain ruggedness. There were few sympatric crossing sites for all species, supporting the use of species‐specific mitigation or wide structures that capture multiple species needs. Inconsistencies were observed between the crossing sites predicted in this study and the Parks Canada proposal. The usefulness of GIS and track data to enhance mitigation projects is illustrated.

Recent increase in body size of the American marten Martes americana in Alaska

Using museum specimens, we studied recent changes in skull size of the American marten Martes americana, in continental Alaska. In Alaska, global warming has resulted in milder winters that may contribute to an improved food supply in the wild. In the present study, we tested the hypothesis that body size of the marten had increased during the second half of the 20th century, in response to global warming. We found that skull size, and by implication body size, increased significantly during the second half of the 20th century, possibly due to an improved food supply and/or lower metabolic demands in winter. Improved food availability in winter may result from the improved nutritional conditions for prey, and/or from increased access to prey resulting from a longer snow-free season. Longitude had a significant positive effect on skull size and a significant negative effect on teeth size. In Alaska, the climate is milder along the western coast and becomes harsher inland. Hence, the milder climate was associated with larger body size providing further support for our prediction that body size of the American marten was influenced by food availability and reduced energy expenditure. The negative relationship between longitude and teeth size may indicate a trend towards a larger prey in inland marten populations, but we have no data to support or refute this hypothesis.

Distribution, Occupancy, and Habitat Correlates of American Martens (Martes americana) in Rocky Mountain National Park, Colorado

A clear understanding of habitat associations of martens (Martes americana) is necessary to effectively manage and monitor populations. However, this information was lacking for martens in most of their southern range, particularly during the summer season. We studied the distribution and habitat correlates of martens from 2004 to 2006 in Rocky Mountain National Park (RMNP) across 3 spatial scales: site-specific, home-range, and landscape. We used remote-sensored cameras from early August through late October to inventory occurrence of martens and modeled occurrence as a function of habitat and landscape variables using binary response (BR) and binomial count (BC) logistic regression, and occupancy modeling (OM). We also assessed which was the most appropriate modeling technique for martens in RMNP. Of the 3 modeling techniques, OM appeared to be most appropriate given the explanatory power of derived models and its incorporation of detection probabilities, although the results from BR and BC provided corroborating evidence of important habitat correlates. Location of sites in the western portion of the park, riparian mixed-conifer stands, and mixed-conifer with aspen patches were most frequently positively correlated with occurrence of martens, whereas more xeric and open sites were avoided. Additionally, OM yielded unbiased occupancy values ranging from 91% to 100% and 20% to 30% for the western and eastern portions of RMNP, respectively.

Determining the Gender of American Martens and Fishers at Track Plate Stations

Determining the gender of American martens (Martes americana) and fishers ( M. pennanti) from track plate stations would significantly augment the information currently gathered from this simple and inexpensive survey method. We used track-plate impressions collected from captured individual martens and fishers of known gender to develop methods to distinguish the gender from tracks. We collected marten tracks from two subspecies M. a. sierrae (tracks n = 54, individuals m = 12, f = 8) and M. a. humboldtensis (tracks n = 109, individuals m = 10, f = 9). We developed a model for martens which performed extremely well (91-100%) using only total track length. For fishers, we collected 64 tracks (from 7 males, 17 females) and developed a 3-variable model, using interdigital pad height, interdigital pad width, and total track length, which correctly classified 98.6% of the tracks. We evaluated track quality on 129 sheets of contact paper collected during summer (dry-season) and 137 sheets collected during fall (wet-season); 100% of dry season compared to 51% of wet season sheets had suitable quality tracks. Gender discrimination of Martes tracks can be used to investigate gender differences in distribution and habitat (associations), but the generality of these findings to other populations is undetermined.

Response of the tiger quoll Dasyurus maculatus to disturbance from selective logging

Summary Data from a trapping and radio-tracking study were used to analyse use of selectively logged and unlogged forest by tiger quolls in moist tableland forest in south-eastern New South Wales. Both male and female tiger quolls were found to use unlogged and some age classes of logged forest significantly more than would be expected from the availability of those classes, and to avoid or use some age classes of logged forest significantly less than their availability would indicate. The use of different age classes of logged forest is discussed in relation to habitat use, ecological requirements and previous logging practices. The results are compared with the response to logging of ecologically similar species, such as American martens (Martes americana), fishers (M. pennanti) and pine martens (M. martes). Forest management implications are discussed in relation to conservation of the tiger quoll and their prey.

Comparing static versus dynamic protected areas in the Québec boreal forest

Conservation planning is often based on static mapping of species’ ranges or habitat distributions. Succession and disturbance alter, however, habitat quality and quantity through time especially under global climate and land use change scenarios; hence, static protected areas may not ensure habitat persistence and species survival. Here, we examined the relative merits of static and dynamic (floating) protected areas for the conservation of American marten ( Martes americana) habitat in a dynamic boreal forest of Québec (Canada). Forest dynamics were modeled using a spatially-explicit landscape disturbance model and protected areas were selected based on the quality and compactness of marten home ranges using MARXAN. Static protected areas were fixed in space during 200 year simulations of boreal forest dynamics, while dynamic protected areas were re-located every 50 years to track dynamic habitat. Dynamic protected areas supported more high quality home ranges through time than static protected areas. The locations of dynamic protected areas were constrained, however, by the highly fragmented forest patterns created through logging and fire in unprotected areas. Our findings emphasize the often-overlooked point that if dynamic conservation planning is to be successful in the long term, the landscape matrix quality surrounding protected areas must be managed in such a way that options remain when it comes to re-planning.

Influence of forest planning alternatives on landscape pattern and ecosystem processes in northern Wisconsin, USA

Incorporating an ecosystem management perspective into forest planning requires consideration of the impacts of timber management on a suite of landscape characteristics at broad spatial and long temporal scales. We used the LANDIS forest landscape simulation model to predict forest composition and landscape pattern under seven alternative forest management plans drafted for the Chequamegon-Nicolet National Forest in Wisconsin. We analyzed 20 response variables representing changes in landscape characteristics that relate to eight timber and wildlife management objectives. A MANOVA showed significant variation in the response variables among the alternative management plans. For most (16 out of 20) response variables, plans ranked either directly or inversely to the extent of even-aged management. The amount of hemlock on the landscape had a surprising positive relationship with even-aged management because hemlock is never cut, even in a clear cut. Our results also show that multiple management objectives can create conflicts related to the amount and arrangement of management activities. For example, American marten and ruffed grouse habitat are maintained by mutually exclusive activities. Our approach demonstrates a way to evaluate alternative management plans and assess if they are likely to meet their stated, multiple objectives.

Winter Home-range Characteristics of American Marten (Martes Americana) in Northern Wisconsin

We estimated home-range size for American marten (Martes americana) in northern Wisconsin during the winter months of 2001–2004, and compared the proportion of cover-type selection categories (highly used, neutral and avoided) among home-ranges (95% fixed-kernel), core areas (50% fixed-kernel) and the study area. Average winter home-range size was 3.29 km2 with home-ranges of males (n = 8, mean = 4.25 km2) significantly larger than females (n = 5, mean = 2.32 km2). Composition of cover-type selection categories in home-ranges differed significantly from what was available in the study area (X2 = 6.9145, df = 2, P > 0.0315) with more highly used habitat and less avoided habitat than expected. Consistent with research in other regions, 72% of an American marten home-range contained highly used cover-types and 18% of a home-range contained avoided types with the remainder of the average home-range composed of neutral cover-types. This suggests that Wisconsin American martens select habitat at the home-range scale based on the occurrence of highly used and avoided cover types. Proportions of selection categories in core areas did not differ significantly from what was available in the study area or in home-ranges. Core areas were significantly smaller than home-ranges and this observation combined with the lack of cover-type selection at the core area scale suggests that American martens select core areas based upon micro-site features (e.g., rest sites) rather than broad-scale cover types. The findings presented here may assist wildlife managers in management activities by identifying potentially suitable habitat.

Apparent Predation of an American Water Shrew, <em>Sorex palustris</em>, by an American Marten, <em>Martes americana</em>

Little is known of the natural history of American Water Shrews, Sorex palustris, including their predators. We document an apparent case of predation of an American Water Shrew by an American Marten, Martes americana, in the boreal forest of southeastern Yukon.

Demographic and Genetic Evaluation of an American Marten Reintroduction: A Comment on Swanson et al.

Molecular genetic techniques have been widely used to evaluate management actions, including the success of species reintroductions. However, conclusions drawn from genetic characterizations must be interpreted in the context of the sampling design and degree of uncertainty underlying genetic parameter estimation and assumptions of analyses performed. For example, failure to correctly identify and sample appropriate groups of individuals for comparative analyses will bias estimates of summary measures of genetic diversity, intersample variance in gene frequency, and derivations of effective population size or degree of reduction or bottlenecks in numerical abundance. We critically evaluate the foundational assumptions underlying the sampling design and analytical methods employed by Swanson and colleagues. Inaccuracies in reporting the founding population history of American marten (Martes americana) in Michigan and high levels of uncertainty underlying estimates of effective population size, bottleneck history, and demographic sustainability suggest that the authors' genetic data are misrepresented.

FIELD USE OF ISOFLURANE AS AN INHALANT ANESTHETIC IN THE AMERICAN MARTEN (MARTES AMERICANA)

We evaluated the effectiveness and practicality of using isoflurane as an inhalation anesthetic with oxygen as a gas carrier for American martens (Martes americana) in a field setting. Sixty-eight martens were trapped in the Waswanipi Cree Model Forest (Québec, Canada) from October to November 2005 and anesthetized with isoflurane in 100% oxygen (1 l/min) using a face mask. Induction setting of isoflurane was 3% for all animals. Mean (+/-SD) length of induction was 1.8+/-1.2 min. Maintenance isoflurane settings ranged from 1% to 4%. Procedures lasted an average of 16.4+/-7.1 min and were uneventful. Length of recovery, defined as the interval between the end of the procedure and animal release, was short (6.3+/-2.8 min), and well below reported lengths of recovery using injectable anesthetics (>/=70 min). As compared to open drop administration of isoflurane described in previous studies, the use of an anesthesia machine prevents the risk of potential fatal anesthetic overdose. We conclude that among anesthesia techniques currently available, isoflurane with oxygen as a gas carrier is a safe and useful field anesthetic in martens, when issues with equipment portability can be overcome.

GEOGRAPHIC AND HOST RANGE OF THE NEMATODE SOBOLIPHYME BATURINI ACROSS BERINGIA

The nematode Soboliphyme baturini Petrov, 1930, was found to represent a single species with a relatively broad geographic range across Beringia and northwestern North America on the basis of the assessment of molecular sequence data for adult and juvenile parasites. Refuted are hypotheses suggesting that several cryptic species could be partitioned either among an array of mustelid definitive hosts or across the vast region that links North America and Eurasia. Host specificity for this species is examined on the basis of a comprehensive list for definitive hosts, derived from new field surveys and existing literature for S. baturini. Only 5 mustelids (Gulo gulo, Martes americana, M. caurina, M. zibellina, and Neovison vison) appear to have significant roles in the life history, persistence, and transmission of this nematode. Soboliphyme baturini readily switches among M. americana, M. caurina, Mustela erminea, or N. vison at any particular locality throughout its geographic range in North America, although Martes spp. could represent the source for nematodes in a broader array of mustelids. Molecular analyses (243 base pairs of mitochondrial gene nicotinamide dehydrogenase [ND4]) suggest that hypotheses for host specificity across an array of mustelid definitive hosts are not supported. The life cycle of S. baturini is explored through a review of diet literature for 2 marten species, M. americana and M. caurina, and other mustelids across the Holarctic. Shrews (Soricomorpha: Soricidae) comprise >8% of prey for these species of Martes, suggesting their putative role as paratenic hosts. Juvenile nematodes found in the diaphragms of soricids are genetically identical to adult S. baturini found in the stomachs of mustelids at the same locations in both Asia and North America, corroborating a role in transmission for species of Sorex.

Evaluating Detection Probabilities for American Marten in the Black Hills, South Dakota

ABSTRACT Assessing the effectiveness of monitoring techniques designed to determine presence of forest carnivores, such as American marten (Martes Americana), is crucial for validation of survey results. Although comparisons between techniques have been made, little attention has been paid to the issue of detection probabilities (p). Thus, the underlying assumption has been that detection probabilities equal 1.0. We used Presence‐Absence data obtained from a track‐plate survey in conjunction with results from a saturation‐trapping study to derive detection probabilities when marten occurred at high (>2 marten/10.2 km2) and low (≤1 marten/10.2 km2) densities within 8 10.2‐km2 quadrats. Estimated probability of detecting marten in high‐density quadrats was p = 0.952 (SE = 0.047), whereas the detection probability for low‐density quadrats was considerably lower (p = 0.333, SE = 0.136). Our results indicated that failure to account for imperfect detection could lead to an underestimation of marten presence in 15–52% of low‐density quadrats in the Black Hills, South Dakota, USA. We recommend that repeated site‐survey data be analyzed to assess detection probabilities when documenting carnivore survey results.

Fasting in the American marten (Martes americana): a physiological model of the adaptations of a lean-bodied animal

The American marten (Martes americana) is a boreal forest marten with low body adiposity throughout the year. The aim of this study was to investigate the adaptations of this lean-bodied species to fasting for an ecologically relevant duration (48 h) by exposing eight farm-bred animals to total food deprivation with seven control animals. Selected morphological and hematological parameters, plasma and serum biochemistry, endocrinological variables and liver and white adipose tissue (WAT) enzyme activities were determined. After 48 h without food, the marten were within phase II of fasting with depleted liver and muscle glycogen stores, but with active lipid mobilization indicated by the high lipase activities in several WAT depots. The plasma ghrelin concentrations were higher due to food deprivation, possibly increasing appetite and enhancing foraging behavior. The lower plasma insulin and higher cortisol concentrations could mediate augmented lipolysis and the lower triiodothyronine levels could suppress the metabolic rate. Fasting did not affect the plasma levels of stress-associated catecholamines or variables indicating tissue damage. In general, the adaptations to short-term fasting exhibited some differences compared to the related farm-bred American mink (Mustela vison), an example of which was the better ability of the marten to hydrolyze lipids despite its significantly lower initial fat mass.

Interacting Effects of Climate Change, Landscape Conversion, and Harvest on Carnivore Populations at the Range Margin: Marten and Lynx in the Northern Appalachians

Assessing the effects of climate change on threatened species requires moving beyond simple bioclimatic models to models that incorporate interactions among climatic trends, landscape change, environmental stochasticity, and species life history. Populations of marten (Martes americana) and lynx (Lynx canadensis) in southeastern Canada and the northeastern United States represent peninsular extensions of boreal ranges and illustrate the potential impact of these threats on semi-isolated populations at the range margin. Decreased snowfall may affect marten and lynx through decreased prey vulnerability and decreased competitive advantage over sympatric carnivores. I used a spatially explicit population model to assess potential effects of predicted changes in snowfall by 2055 on regional marten and lynx populations. The models' habitat rankings were derived from previous static models that correlated regional distribution with snowfall and vegetation data. Trapping scenarios were parameterized as a 10% proportional decrease in survival, and logging scenarios were parameterized as a 10% decrease in the extent of older coniferous or mixed forest. Both species showed stronger declines in the simulations due to climate change than to overexploitation or logging. Marten populations declined 40% because of climate change, 16% because of logging, and 30% because of trapping. Lynx populations declined 59% because of climate change, 36% because of trapping, and 20% in scenarios evaluating the effects of population cycles. Climate change interacted with logging in its effects on the marten and with trapping in its effects on the lynx, increasing overall vulnerability. For both species larger lowland populations were vulnerable to climate change, which suggests that contraction may occur in the core of their current regional range as well as among smaller peripheral populations. Despite their greater data requirements compared with bioclimatic models, mesoscale spatial viability models are important tools for generating more biologically realistic hypotheses regarding biotic response to climate change.

Human-Caused Mortality and Population Trends of American Marten and Fisher in a U.S. National Park

American marten (Martes americana) and fisher (M. pennanti) are susceptible to overharvest. National Park Service policies require managers to ensure long-term population viability of native wildlife while concurrently provide recreation opportunities, which can include harvest of wildlife. I investigated human-caused mortality factors of American martens and fishers in Pictured Rocks National Lakeshore (PRNL), Michigan, from May-December 2001-2005. Thirty-five martens and 14 fishers were captured and survival was monitored using radio telemetry. Four martens were legally trapped, one marten was killed by a vehicle collision within PRNL, and three martens died of natural causes. The only fisher mortality was through legal trapping within PRNL. In addition, vehicles in the study area killed an uncollared marten and fisher. Greatest marten mortality occurred during the harvest season in December, with only males reportedly harvested. Overall, marten and fisher survival from June-December was 0.803 (95% confidence interval [CI]: 0.689 to 0.882) and 0.812 (95% CI: 0.374 to 0.977), respectively. Using survival rates from this study and reported rates of fecundity, I estimated that current marten mortality rates are sustainable and that the population was increasing at a rate of 16%/year. Survival data and harvest records suggest that the fisher population is stable or increasing. Human-caused mortality appears to be the greatest source of mortality for martens and fishers at PRNL. Although current harvest rates are comparatively low, continued monitoring of harvest within and adjacent to PRNL, in addition to monitoring vehicle collisions, is warranted to ensure viable populations are maintained.

Habitat Selection by American Martens in Coastal California

ABSTRACTWe investigated habitat selection using single‐ and mixed‐scale modeling at 2 spatial scales, stand and home range, by the only known population of American martens (Martes americana) remaining in the historical range of the Humboldt subspecies (M. a. humboldtensis) in California, USA. During 2000 and 2001, we sampled a 12 times 14 grid with 2‐km spacing, using 2 sooted track plates at each grid point. We detected martens at 26 of the 159 grid points. We used resource selection probability functions and an information‐theoretic method to model habitat at detection locations. At the stand scale, martens selected conifer‐dominated stands with dense, spatially extensive shrub cover (x̄ = 74% cover, SE = 4) in the oldest developmental stage. At the home‐range scale, martens selected the largest available patches (x̄ = 181 ha, SE = 14) of old‐growth, old‐growth and late‐mature, or serpentine habitat. Mixed‐scale models revealed that habitat characteristics from both scales best explained marten occurrence compared to one scale alone. Dense, spatially extensive shrub cover is a key habitat element for martens in coastal forests. Dense shrubs provide refuge from predators, cover for prey, and may also deter larger‐bodied competitors. Managers can increase the likelihood of marten population persistence and encourage expansion in coastal forests by maintaining and restoring late‐mature and old‐growth, conifer‐dominated forests with dense shrub cover in large, contiguous patches.

An acoustic technique for monitoring off-highway vehicle (OHV) use with sound level meter data: Camparison with Trailmaster records

Off-highway vehicle (OHV) use is of growing interest to land managers. Trail counters are typically used to monitor OHV activity, but accuracy of this technique remains relatively untested. As part of an ongoing study comparing the distribution of American martens (Martes americana) with OHV use in the Lake Tahoe Basin, verifiable OHV detections were collected using two techniques, (1) photographs from Trailmaster 1500 camera systems (TMs) placed across roads/trails and (2) continuous 2-s, A-weighted equivalent-continuous sound levels (LAeq2s) collected using Larson-Davis 720 Sound Level Meters (SLMs) placed either near roads/trails or paired with TM animal detection stations. Events were identified in the SLM data by comparing time-history profiles collected in the field with profiles of known snowmobile passes. Errors in SLM event counts were assessed using independent observer logs and compared with the TM records. SLMs were consistently more reliable detectors of snowmobile use. During the Winter 2004 season, TM records were reliably matched to SLM logs only 48% of the time. TMs consistently missed passes and overestimated events compared to SLMs. In conclusion, SLMs proved to be more sensitive and reliable detectors of OHV activity. These results have implications in both wildlife research and land management applications.

A method of genetic identification of pine marten (Martes martes) and stone marten (Martes foina) and its application to faecal samples

AbstractReliable identification of species occurring in a given area is a basis of effective wildlife management and conservation. However, discrimination of species is often difficult, especially if two morphologically similar, rare and elusive species occur sympatrically. This is the case with pine marten Martes martes and stone marten Martes foina, two closely related mustelids that have overlapping ranges throughout central Europe. Here we describe a genetic method that allows for distinguishing non‐invasively collected samples (faeces or remotely plucked hair) derived from pine martens or stone martens. On the basis of the analysis of tissue samples of 31 pine martens and 26 stone martens, we found that the microsatellite locus Ma18– developed in another study for American marten Martes americana– differs substantially in allele lengths between pine martens and stone martens, thereby allowing a genetic distinction of these species. We propose combining the use of the locus Ma18 with the second one described in the literature as having the same properties. The simultaneous application of these two markers allows for unequivocal species identification. To test the practical use of this method, we analysed 365 faecal samples collected in the vicinity of the town Rogów (51°48′N, 19°53′E) in central Poland, where pine martens and stone martens occur sympatrically. We successfully identified 78 scats of stone martens and 155 of pine martens. We found that the faeces of both martens occurred inside forest complexes of the study area. Thus, it is impossible to draw any inferences on the marten species solely from the type of habitat where the faeces were found. Genetic identification of faeces or hair provides a reliable and relatively cheap method of determining the presence of two species of European martens. Its application enables the monitoring of changes in their distribution, which is important because of their different demographic trends and conservation status.

Genetic isolation by distance and landscape connectivity in the American marten (Martes americana)

Empirical studies of landscape connectivity are limited by the difficulty of directly measuring animal movement. ‘Indirect’ approaches involving genetic analyses provide a complementary tool to ‘direct’ methods such as capture–recapture or radio-tracking. Here the effect of landscape on dispersal was investigated in a forest-dwelling species, the American marten (Martes americana) using the genetic model of isolation by distance (IBD). This model assumes isotropic dispersal in a homogeneous environment and is characterized by increasing genetic differentiation among individuals separated by increasing geographic distances. The effect of landscape features on this genetic pattern was used to test for a departure from spatially homogeneous dispersal. This study was conducted on two populations in homogeneous vs. heterogeneous habitat in a harvested boreal forest in Ontario (Canada). A pattern of IBD was evidenced in the homogeneous landscape whereas no such pattern was found in the near-by harvested forest. To test whether landscape structure may be accountable for this difference, we used effective distances that take into account the effect of landscape features on marten movement instead of Euclidean distances in the model of isolation by distance. Effective distances computed using least-cost modeling were better correlated to genetic distances in both landscapes, thereby showing that the interaction between landscape features and dispersal in Martes americana may be detected through individual-based analyses of spatial genetic structure. However, the simplifying assumptions of genetic models and the low proportions in genetic differentiation explained by these models may limit their utility in quantifying the effect of landscape structure.