GEOG 560 Final Project: GIS Analysis of Pacific Marten

GEOG 560: GIScience 1: Introduction to Geographical Information Science

Fall 2020, Oregon State University

Pacific marten at Yellowstone National Park, NPS

Along with other carnivore species, Pacific marten distribution has declined, and available habitat has been reduced and isolated since the early 1990s. Although it isn’t completely clear what is causing the loss of marten distribution, it is well documented Pacific martens are impacted through changes in their habitat from timber harvest and land clearing. Additional impacts include mortality through trapping and car strikes, recreation, and disturbance through the human footprint. My Master of Natural Resources capstone project is looking at the impact of the human footprint on Pacific marten through the presence and level of use of roads, trails, campgrounds, and buildings at Crater Lake National Park, Lassen Volcanic National Park and the surrounding National Forest of each. GIS is an integral tool in analyzing wildlife distribution in relation to other variables. For this project, I reviewed the literature for research utilizing GIS for Pacific and American martens, and for research utilizing GIS in comparing impact to carnivores from the human footprint.


Baigas, P. E., Squires, J. R., Olson, L. E., Ivan, J. S. & Roberts, E. K. (2017). Using environmental features to model highway crossing behavior of Canada lynx in the Southern Rocky Mountains. Landscape and Urban Planning 157(2017), 200-213. http://dx.doi.org/10.1016/j.landurbplan.2016.06.007

Carnivores are especially sensitive to reduction in their habitat due to human disturbance and habitat fragmentation. Previous studies show crossing zones for wildlife species tend to be clustered spatially, suggesting habitat influences or road characteristics. This study looked at road crossing characteristics in the Southern Rocky Mountains of Colorado, USA for time of day, road avoidance, and landscape variables. They GPS collared 14 Canada lynx during the winters of 2010-2012. The GPS units collected locations every 20-30 minutes, and were programmed to fall off later. Vegetation characteristics at lynx crossing points were measured, and highway characteristics were measured. The researchers used remotely-sensed topographical and vegetation layers at two scales: fine scale and landscape scale. They used the Geospatial Modelling Environment (GME) to create and run simulations. GME uses the program R and ERSI Arc GIS. Most lynx in their study did not avoid highways (likely due to habitat configuration and placement of highways), and crossed on average every other day. Lynx mitigated risk of crossing by doing so at night when traffic was less. Lynx were more likely to cross in places with more vegetative cover, and on a landscape scale, on north-facing slopes and in areas with topographical concavity such as river drainages. This study’s use of GIS is more complex than I plan on using for my project on Pacific marten, but is relevant in a carnivore species’ use or avoidance of the human footprint and habitat fragmentation, both of which can be analyzed using GIS.


Baker, A. D. & Leberg, P. L. (2018). Impacts of human recreation on carnivores in protected areas. PLoS ONE 13(4), e0195436. https://doi.org/ 10.1371/journal.pone.0195436

Protected areas are meant to protect species from threats, however human disturbance in protected areas can have negative impacts on wildlife. Mammalian carnivores in particular are at risk from human disturbance due to their relatively larger body size, larger home ranges, longer lifespans, lower fecundity, longer generation times, and smaller population densities. This study sought to compare mammalian carnivore occupancy in three Arizona protected areas with different levels of disturbance: low, moderate, and high. GIS was used to determine survey locations (for remote cameras, track plates, and natural sign surveys) using the random point generator in ArcGIS, and each survey’s location to the human footprint was determined using ArcGIS. Generally, uncommon carnivores had higher occupancy in the low disturbance protected area, and common carnivores had high occupancy in the high disturbance protected area. Just the presence (not necessarily level of use) of roads and trails had a negative influence on most species. This research is very relevant for my capstone project, as it suggests sensitive species such as the Pacific marten are likely to be negatively impacted by the human footprint. Only one species in their study, the badger, is in the same family as the Pacific marten. It had one of the lowest occupancies overall, and appear to be among the most sensitive to human disturbance.


Baltensperger, A. P., Morton, J. M., & Huettmann, F. (2017). Expansion of American marten (Martes americana) distribution in response to climate and landscape change on the Kenai Peninsula, Alaska. Journal of Mammalogy 98(3), 703-714. DOI:10.1093/jmammal/gyx011

The Kenai Peninsula in Alaska, USA, is a subarctic ecosystem that is shifting dramatically due to climate change. In particular, temperatures are warming, causing shifts in biomes. American martens (Pacific martens were recently designated a separate species from the American marten) have been expanding westward over the past 60 years, with particular expansion in the last 15 years (publication date 2017). One theory for marten expansion is habitat change in the form of forest change due to climate shifts. Another theory is a population recovery after a wildlife poisoning effort, over-trapping, and two wildfires. Additionally, marten detection was positively associated with human features: trails, recreation sites, cabins, and to a lesser extent, villages. This could be coincidence as forest cover occurs in narrow valley bottoms on the Kenai Peninsula, which is where human features are located. Or, it could be martens using human features for access to prey, protection from predators, or for resting sites. The researchers used GIS extensively in their study. When exact points of marten detections were unknown, GIS was used to randomly plot the point in the unit of detection. The researchers created a model and used the Extract Values to Multi-point tool to attribute environmental predictors to marten locations. The model was projected to a 1-km lattice of points using the Create fishnet tool, and was rasterized. This made continuous maps that predicted the indices of marten occurrence. Continuous models were reclassified into binary rasters that showed predicted absences and predicted presences. The Raster Calculator was used to determine areas of loss, gain and persistence in marten distribution. This study is relevant for my capstone project because it shows a potential relationship between martens and the human footprint. Other research I’ve read show a negative relationship between martens and the human footprint, and this shows a potential positive relationship.


Fecske, D. M., Jenks, J. A., & Smith, V. J. (2002). Field evaluation of a habitat-relation model for the American marten. Wildlife Society Bulletin 30(3), 775-782.

This 18 year old study created and tested a habitat-relation model for American martens in the Black Hills of South Dakota, USA. The researchers used a USDA Forest Service GIS database of the Black Hills that contained dominant overstory species, percentage canopy cover, and stand size. The GIS also had a line graph stream database, and a digital elevation model database. The habitat-relation model was created by recoding each GIS database with American marten habitat quality ranks. To determine distribution of American martens in the study area, field surveys were conducted using baited track-plate boxes. The results of the field study and habitat-relation model were compared and the habitat-relation model was satisfactory at predicting detection of the American marten, and performed better at predicting where martens would not occur. The limitations of the model were discussed by the authors with suggestions on how to improve. The relevance to my capstone project on Pacific martens is that specific habitat quality metrics were not collected as part of the original data collection, so I plan to overlay a predicted Pacific marten habitat layer that is based on aerial imagery. This study by Fecske et al. (2002) is support for habitat relation models.


Fisher, J. T., Anholt, B., Bradbury, S., Wheatley, M., & Volpe, J. P. (2012). Spatial segregation of sympatric marten and fishers: the influence of landscapes and species-scapes. Ecography 36, 240-248. doi: 10.1111/j.1600-0587.2012.07556.x

Fisher and the American marten (both members of the family Mustelidae) are found to segregate in slightly different habitats and also co-exist. The fisher is about three times the size of the marten, and their prey species overlap considerably. The authors sought to determine if including a potential competitor in a species habitat model improves the ability to predict species occurrence in shared landscapes. In the Rocky Mountains of Alberta, Canada, researchers set baited sampling sites with hair snares and camera traps to determine fisher and marten occurrence. To create a habitat model, they use a LandSat thematic mapped GIS land cover data set. Digital elevation models were classified using a habitat-identification algorithm. Out of 16 potential land-cover types, 7 were hypothesized to be associated with fishers or martens. They used ArcGIS 9.3 Spatial Analyst to geo-reference each sampling site on the habitat layer. To calculate the percent of each land-cover type, they used a combination of spatial analysis routines. The results indicate marten distribution was best explained by land cover, fragmentation and fisher occurrence. Fisher distribution was best explained by land cover and marten occurrence. They sometimes occur together, but not any more than predicted by chance. Similar patterns of species segregation have been documented in other species such as black and grizzly bears. When accounting for habitat, topography, and fragmentation, the probability of detecting either marten or fisher was predicted by the absence of the other. This research is relevant for my project in how they used a GIS to overlay potential habitat with occurrences. It is also interesting in terms of marten distribution in the study areas and the presence or absence of fishers.


Heinemeyer, K., Squires, J., Hebblewhite, M., O’Keefe, J. J., Holbrook, J. D., & Copeland, J. (2019). Wolverines in winter: indirect habitat loss and functional responses to backcountry recreation. Ecosphere 10(2): e02611.

Outdoor recreation is increasingly shown to impact wildlife and nature. As climate change reduces snowpack amount, coverage, and duration, conflict between winter recreation and conservation of sensitive species in those areas is predicted to increase. Wolverines naturally occur in low densities, have low reproductive rates, and are active in winter. These characteristics put them at risk to impacts from winter recreation. Researchers fitted wolverines with GPS collars in Idaho, Wyoming and Montana, and collected GPS data from recreationists. They used ArcGIS to develop maps of habitat, recreation intensity, type of recreational use, and habitat models. The data show both male and female wolverines had a negative response to increasing levels of recreation, especially from off-road motorized recreation, resulting in an indirect loss of available habitat. This is especially important for female wolverines, as they showed a stronger avoidance. Winter recreation and female denning overlap in late winter and early spring. Loss of habitat due to avoidance of recreation could have a negative impact on successful wolverine reproduction. This study is relevant to my project on Pacific marten as there is winter recreation in marten habitat. Pacific marten and wolverines are in the same family Mustelidae, and both suffer from low population densities.


Jenkins, K. J., Griffin, P. C., & Reid, M. E. (2014). Indicators for habituated and food-conditioned Cascade red foxes in Mount Rainier National Park: preliminary assessment. U.S. Geological Survey Administrative Report to Mount Rainier National Park, U.S. National Park Service.

The Cascade red fox is a rare subspecies of the red fox found in limited areas of Mount Rainier National Park and Gifford Pinchot National Forest. Despite its rareness, during winter individuals are frequently seen along roads in Mount Rainier National Park begging for food. Researchers sought to document food conditioned foxes’ primary locations in the park, examine environmental factors for fox distribution, and trends in the distance of fox locations to human use areas. They fitted three foxes with GPS collars that transmitted the foxes’ location every 3.5 hours. A resource selection probability function (RSPF) was developed to describe variation in the relative probability of habitat use. At each point of fox detection, the slope, elevation, distance to the main road, and distance to a developed human use area was extracted using ArcGIS. Six classes of use were created in ArcGIS with raster feature datasets. ArcGIS was also used to analyze the data. Two of the three foxes were closely associated with high human use areas, especially in winter and early spring, but also late spring and early summer. In my project I’ll be looking at Pacific marten detections in relation to human-use areas, so the authors’ use of ArcGIS is useful for how I might analyze the data. This study is also very interesting because rare animals are not often frequently seen by humans. Frequent sightings can lead to incorrect assumptions about population sizes.


Kirk, T. A., & Zielinski, W. J. (2009). Developing and testing a landscape habitat suitability model for the American marten (Martes americana) in the Cascades mountains of California. Landscape Ecology. DOI 10.1007/s10980-009-9349-5

American marten (martens in California have been reclassed as Pacific martens) populations have been declining in California since the 1920s, and their range has contracted in northeastern California. This study sought to determine if current marten distribution can be explained by landscape level sensitivity to forest conditions. Martens were surveyed in the mountains of northeastern California using sooted track plates and remote cameras. ArcInfo and ArcMap 8.3 were used to measure 18 habitat features, and to assess layers with infrastructure, hydrology, and vegetation type in conjunction with marten detections. Researchers found martens clustered in three areas, and that populations are influenced by the distribution of habitat at the scale of a marten’s home-range. The highest density of martens was in the largest protected area, and 60% of detections were in or near wilderness. These results are consistent with studies done elsewhere, and adds support that high-elevation and late-seral forests are important for martens. For my project on Pacific marten, this study is useful in terms of comparing marten locations with habitat. I would like to use habitat data in my project to ensure marten detections in relation to the human footprint are not a result of difference in habitat.


Linnell, M. A., Moriarty, K., Green, D. S., & Levi, T. (2017). Density and population viability of coastal marten: a rare and geographically isolated small carnivore. PeerJ 6:e4530, DOI 10.7717/peerj.4530

The Humboldt marten is a subspecies of Pacific marten that occur in coastal southern Oregon and coastal northern California. Instead of inhabiting higher elevation, late seral forests with snow, Humbolt martens live in coastal forests with no or limited snow cover. Like other marten populations, Humbolt marten populations have also decreased, and were considered for listing under the Endangered Species Act in 2015. They were not listed due to lack of current information on population size and habitat. This study sought to create baseline data of marten density, population size, and population viability. Using spatial mark-resight models, researchers determined the Oregon population of coastal martens is less than 87 adults in two subpopulations separated by a barrier (river). The subpopulations are small enough they are at risk of extirpation. A GIS was used in this project to create a raster layer of habitat, specifically vegetation and openings that would affect marten movement. Trap locations and marten detections were analyzed using a GIS. This research is useful to my project in using a GIS to geographically show marten locations in relation to habitat and other features. It is also interesting in that Humbolt martens survive without snow, which is often cited as a necessary component of Pacific marten habitat.


Mowat, G. (2006). Winter habitat associations of American martens Martes americana in interior wet-belt forests. Wildlife Biology 12(1), 51-61, https://doi.org/10.2981/0909- 6396(2006)12[51:WHAOAM]2.0.CO;2

Previous research has shown American martens are found in coniferous and mixed coniferous forests, and the physical structure of the forest is more important than tree species. Other research has suggested spruce and fir forests are preferred by martens. The goal of this study was to test the association between marten occurrence and various habitat measures. Marten detections were collected in the Selkirk Mountains and Central Purcell Mountains in southeastern British Columbia, Canada. Habitat information was derived from a GIS database, including forest type and age, openings, and presence of roads. The author found the most important factors for marten habitat selection at a larger scale were climax ecosystems and stand types, and at a smaller scale, stand age and crown closure were most important. Martens avoided areas with broad-scale canopy fragmentation. Human use of the landscape in the form of roads and logging was not impactful to marten detection, though both occurred in low rates, especially during the winter study period. This research is interesting to my project in that human presence or use did not have an impact on marten detections and did not appear to reduce available habitat, which is counter to other research on carnivore species. The author speculated the lack of impact could be from a low level of human disturbance during winter.


Olson, L. E., Squires, J. R., Roberts, E. K., Miller, A. D., Ivan, J. S., & Hebblewhite, M. (2017). Modeling large-scale winter recreation terrain selection with implications for recreation management and wildlife. Applied Geography 86(2017), 66-91. http://dx.doi.org/10.1016/j.apgeog.2017.06.023

Motorized and non-motorized winter recreation is increasing, creating the potential for conflict between user groups and the environment. This study sought to measure movement characteristics of winter recreationists, use models to predict preferred landscape characteristics, and to understand characteristics of potential conflict. The researchers collected GPS data on volunteer winter recreationists in the Colorado Rocky Mountains, USA. ArcGIS was used to review GPS points, remove errors, and to calculate the distance between points and differences in elevation. GPS data was also analyzed with environmental covariates in ArcGIS. The data showed motorized and non-motorized recreationists chose different terrain. Motorized recreationists chose areas further from highways with greater road densities, open forest canopy and shallower slopes. Non-motorized recreationists chose areas closer to highways, denser forest canopy, steeper slopes, and more terrain variability. Nearly all recreation occurred during daylight hours, decreasing potential impact to nocturnal and crepuscular animals. The authors state a lack of research on winter recreation land use patterns. If a conflict is found between winter recreation and martens, this study could help land managers make decisions, such as concentrating use in certain areas or closing important marten habitat.


Olson, L. E, Squires, J. R., Roberts, E. K., Ivan, J. S., & Hebblewhite, M. (2018). Sharing the same slope: behavioral responses of a threatened mesocarnivore to motorized and nonmotorized winter recreation. Ecology and Evolution 2018(8), 8555-8572. DOI: 10.1002/ece3.4382

Winter recreation is increasing from improvements in gear and growing human populations. Snow packs are decreasing both spatially and temporally, setting the stage for conflict with wildlife in winter recreation areas. Winter recreation in the form of non-motorized backcountry travel, motorized backcountry travel, and ski resorts have the potential to impact wildlife in different ways. This study aimed to examine the impacts of dispersed and developed winter recreation in Canada lynx in Colorado, U.S.A. GPS data was collected from lynx and winter recreationists. GPS locations were converted into density rasters in ArcGIS using the Point Density tool. For each recreation type and year of study, density rasters were calculated separately. Distance from each lynx GPS point was measured in a GIS to the nearest recreation type. The authors found a nuanced response of lynx to winter recreation. Lynx exhibited strong avoidance of developed ski resorts, especially at busy times. In areas with low to moderate recreation intensity, lynx showed spatial tolerance, and modified their behavior by increasing activity at night, and moving more cautiously. This suggests Canada lynx can tolerate low to moderate recreation in their habitat. This research is relevant to my project on Pacific marten in that I hope to look at levels of use of the human footprint to determine if martens can tolerate low use, but perhaps avoid high use.


Slauson, K. M., & Zielinski, W. J. (2008). American marten population monitoring in the Lake Tahoe Basin. U.S.D.A. Forest Service, Pacific Southwest Research Station.

This document by Forest Service researchers describes a monitoring program and protocol for martens in the Lake Tahoe Basin. The authors identified stressors to martens such as roads, ski areas, vegetation management and urbanization. The stressors will be measured in a GIS for each marten sample unit and compared with marten occurrence data. Spatial and temporal extent of stressors will be accounted for, in addition to its intensity. This document is 12 years old, and I have not yet come across data based on the monitoring protocol they establish. Since they identify roads as a stressor to account for, any data from that would be useful for my project.


Slauson, K. M., & Zielinski, W. J. (2009). Characteristics of summer and fall diurnal resting habitat used by American martens in coastal northwestern California. Northwest Science 83(1), 35-45. doi.org/10.3955/046.083.0104

This study documented and analyzed resting habitat for the coastal subspecies of Pacific marten, the Humboldt marten. Martens have a long thin body shape which helps efficiently hunt prey. The downside is high costs for thermoregulation. To regulate body temperature, martens use resting habitats to stay warm and to provide protection from predators. For this study, martens were trapped, outfitted with VHF radio collars and tracked to resting sites. At each location, stand measurements were taken. A GIS was used to analyze resting locations. Specifically, the developmental stage and composition of each stand was derived from vegetation layers in a GIS. A GIS was also used to determine proportions of stand types. Martens were found resting in snags, logs, live-trees, slash-piles, rock-piles, and shrub clumps. These structures were in chambers, cavities, broken tops, branch platforms, ground site, and basal hollows. This data could be used as recommendations for managers in providing quality habitat for Pacific marten as part of my project.


Slauson, K. M., Zielinski, W. J., & Schwartz, M. K. (2017). Ski areas affect Pacific marten movement, habitat use, and density. The Journal of Wildlife Management 81(5), 892-904. DOI: 10.1002/jwmg.21243

Alpine ski recreation is a popular activity both globally and on the west coast, and has the potential for negative impacts to wildlife. This study sought to evaluate Pacific marten movement occupancy and density in ski areas and control areas in the Lake Tahoe region of California, U.S.A. A GIS was used to develop a vector-based approach to measure marten movement paths. Ski runs were digitized and analyzed in the context of forest edges and where martens might cross between survey stations.  Researchers found martens occupied ski resort areas less in winter compared to control areas, with females showing a higher level of avoidance. Ski runs and roads caused habitat fragmentation that resulted in 41% less habitat connectivity. When martens crossed non-forested slopes, they did so at the narrowest parts in all seasons. Additionally, marten age was lower in ski resort areas, suggesting a possible population source-sink situation. Martens are at risk for predation when crossing open areas, so martens frequently crossing ski runs and roads at ski resorts may have higher mortality. This study is extremely relevant to my project on Pacific marten as it shows an impact to martens due to both the human footprint through habitat fragmentation from ski runs and roads and also from human presence at the resorts during winter.

Questions or Comments?

Contact Deborah Hill: hilldeb@oregonstate.edu