THE WILDLIFE SOCIETY Remotely Wild
Newsletter of the Spatial Ecology & Telemetry Working Group
Issue 33 Spring 2020
From the Working Group Chair A Difficult Time:
We bring you this newsletter at a difficult time. As the world responds to the Coronavirus pandemic, we all go through our own shocks as we adjust and prepare. We worry about our health, and even more for our loved ones. We worry about the economy and our future, as businesses shut down and our 401Ks tumble. We worry about our jobs and our work, and our ability to pay the bills.
In wildlife management and research, we are fortunate in that we often work in more isolated conditions than most professions. We are unlikely to contract this disease when we sit alone on a mountain, watching in fascination at a world that amazes us. But many of us work in jobs that have regular contact with the public, or are in school or teach. We face the same threats the rest of the world does.
As schools shut down or move online, we who are parents are adapting to life with children who are now home all day. Those of us who teach struggle to shift our classes online. Those of us who are students worry about our education. Conferences and professional meetings are of course shutting down, and rightly so. Mariah Simmons, TWS Unit Services Manager, is maintaining a running list of TWS event cancellations and postponements that you can check at the link below. Note that there are separate tabs describing regional travel restrictions and events impacted.
Social Isolation:
As you all know, governments around the world are taking aggressive steps to contain this virus. We are all learning about “social distancing.” This pandemic will pass, though, and the social isolation we are imposing on ourselves will reduce the damage and save lives. The downside of social isolation, of course, is that it isolates, and we are a social species. We may all be well-advised to reach out occasionally, to colleagues and loved ones, just to check in and reconnect. Please know that you are not alone as we collectively face this global threat.
What can we do to help?
Here at SETWG, we will try to keep our little part of the world going. In this newsletter you will find some interesting articles from our 2019 travel grant recipients, describing their research in movement ecology, carnivore interactions, and effects of sampling methods on defining population sizes. We also have some announcements about our SETWG awards program, the 2020 national TWS conference in Kentucky, and upcoming elections. We will also be in touch more regularly with you in the future. Do you have ideas that could help our members? If so, please let us know! We will be happy to share with the working group. For example, GIS professors struggling to transition to online courses may be interested this resource from the Science Education Resource Center (SERT) and the National Association of Geoscience Teachers (NAGT): https://serc.carleton.edu/teachearth/ teach_geo_online/index.html
Thank you for reading, and thank you for being a part of the Spatial Ecology and Telemetry Working Group! Best regards, Jeff Jenness ([email protected]) TWS Event Cancella ons & Postponements: h ps://docs.google.com/spreadsheets/u/2/d/e/2PACX-1vQoHjh- rH5TKdJaJz4sXnuX-wMCli8OOIXf0nxf9wzO6fzI-llqcE5MwwDzu-UFdknn71G2t7eCZdA-/pubhtml?urp=gmail_link SETWG
In this issue: Fg 1: From the Working Group Chair. Pg 2: SETWG annual Treasurer’s report Pg 3: Conference announcement & executive team update Pg 4: SETWG Awards - solicitation for nominations Pg 5: Movement Ecology tools Pg 6: How you define your population matters: Making inference about habitat associations varies depending on the sampling method used Pg 11: Modeling Carnivore Interactions in Northeastern Oregon Using Activity & Occupancy Patterns Pg 17: Movement ecology and space-use of mountain lions in wild West Texas
Treasurer’s Report at a glance: 2020
Balance as of 1/1/2019 $5,469 2019 Total Income $3463 2019 Total Expenses $3100
Current balance $5,832
Membership 224
WHERE IN THE WORLD ARE SETWG MEMBERS..?
Remotely Wild - Spring 2020 2 SEQUOIA CLUB
2020 National TWS Conference The 2020 National TWS conference is currently scheduled for September 27 – October 1, 2020, in Louisville, Kentucky. Naturally this may change depending on the status of the coronavirus pandemic, but for the time being we will hope for the best and assume it will proceed as planned. Travel Grants:
SETWG traditionally provides a few travel grants to students and early professionals to help them make the trip, and to help them participate in our professional community. We will make an announcement with the details soon, but for the time being please let your colleagues and/or students know this is in the works.
Conference Events: We have two events proposed for the conference, and which are currently being decided on by the council. If approved, we will be sponsoring a pair of workshops teaching us how to use the Google Earth Engine, and a special poster session illustrating innovative uses of GIS in wildlife management and research. We’ll be in touch with details when we hear back from the council.
We are also supporting a symposium on long-term datasets proposed by the Biological Diversity Working Group. This, too, will be decided by the TWS council, but we have our fingers crossed for BDWG. 2020 SETWG Elections The current set of working group officers are nearing the end of their 2-year terms and it is time to pass the torch. Would you like to serve as a working group officer? We have a large and dynamic working group and this is a great opportunity to get involved. The working group needs you and you’ll enjoy the work! The Spatial Ecology and Telemetry working group has three officers. All positions are 2-year terms and all are up for election. If you would like to know more about the duties involved in a particular office, please contact the current officer and we’ll be happy to discuss it:
Chair: Jeff Jenness, [email protected] Treasurer: Kathy Zeller, [email protected] Secretary: Alex Wolf, [email protected] To be a candidate, please send your name, the office you are running for, a brief biography, and a sentence or two explaining why you want to run, to Alex Wolf at [email protected]. The deadline for submissions is August 28, 2020. We will compile all the candidate information and send it to the working group, and then hold online elections for a couple of weeks and announce the new officers before the national TWS conference in Louisville.
Remotely Wild - Spring 2020 3 SETWG SETWG Awards 2020 Solicitation for nominations:
The Spa al Ecology and Telemetry Working Group is excited to announce that we are accep ng nomina ons for 2020 awards that recognize professionals in the field of GIS, Spa al Ecology, Remote Sensing & Biotelemetry who have made significant contribu ons to the field of wildlife biology. Award recipients do not need to be wildlife biologists or even involved in any environmental research or management. They only need to have wri en or produced something, or provided some service that has substan ally improved our ability to do our job and enabled us to do things we may not have been able to do before. Past recipients include the developers of so ware packages such as the adeHabitat and unmarked packages for R, the Home Range Tools and ArcMET extensions for ArcGIS, Circuitscape, and Fragstats, among many others.
Although our awards do not include any kind of cash prize, they are a way for us, as a professional society, to say thank you to these individuals for the help they have given us. If you believe that a person or a group deserves special recogni on for a service that they have provided the spa al ecology community, please send an email with their name, affilia on and a brief descrip on of why they should receive an award to the 2020 SETWG award commi ee: [email protected]
4 SEQUOIA CLUB Movement Ecology Highlighting R-based tools for analyses
Movement ecology is a quickly growing subdiscipline that combines both of our favorite things here at SETWG, spa al ecology and telemetry. There is now a dedicated journal, Movement Ecology, for research specifically focused on this topic. There was an en re Gordon Research Conference on movement ecology this year. There have also been special issues in journals and symposia at society mee ngs dedicated to this topic. And there was much interest in the habitat selec on and movement ecology workshop we sponsored at this year’s annual TWS conference (and a request from members for yet another one next year).
The field is growing in part due to the plethora of telemetry data that is being collected (and made available through sites like MoveBank), and in part due to our increased capacity to analyze these data in complex and interes ng ways. This burgeoning of techniques for analyzing movement data can be overwhelming as can the sheer number of R packages available to employ these techniques. Because of this, we wanted to highlight a recently published paper in The Journal of Animal Ecology en tled Naviga ng through the R packages for movement.
Rocío Joo and co-authors reviewed 58 R packages that can be used to analyze movement data. They cover the gamut of op ons for movement data analysis, outline the packages that can be used for each one, and even provide a handy reference table. For example, they cover packages that can be used in data pre-processing for data like global loca on sensor data, radio-tags, and accelerometry and magnetometry data. They iden fy packages that offer func ons for data cleaning, data explora on, and calcula ng metrics like step lengths and turning angles. They write about categorizing movement data into units like steps or paths, or categorizing the data into different behavioral states with hidden Markov models. Then, they go on to describe packages that can be used in analyses like home range es ma on, habitat use, and interac ons among tagged individuals. They also provide informa on on packages that simulate movement trajectories and allow for visualiza on, like crea ng anima ons of animal movement from collar or other tag data. William C. Campbell They helpfully point out package dependencies, for example, objects or func ons from one package are needed as inputs to another package.
If you are just ge ng started with movement ecology or are seasoned at it, this paper is definitely worth a read and helps sort out the some mes confusing array of R packages that are available to analyze tracking data in a handy reference table.
Remotely Wild - Spring 2020 5 SETWG How you define your population matters: Making inference about habitat associations varies depending on the sampling method used Sarah B. Bassing, PhD student University of Washington [email protected]
I received a student travel grant from the Spa al Ecology and Telemetry Working Group to a end the American Fisheries Society and The Wildlife Society 2019 Joint Annual Conference in Reno, NV this fall. I was honored to receive this award and thrilled to give an oral presenta on en tled “Poten al biases in camera trap data when monitoring mul ple species," on behalf of my coauthors at the conference. This research is part of the Washington Predator-Prey Project, a collabora ve project between the University of Washington and the Washington Department of Fish and Wildlife. More about the larger study can be found at h ps://predatorpreyproject.weebly.com/
Remotely Wild - Spring 2020 6 SETWG
Camera traps are widely used for monitoring wildlife species. Although camera data can yield inferences about resource selec on and other metrics of interest similar to those made from other data collec on methods (e.g., telemetry), most compara ve studies focus on a single species specifically targeted by the camera trapping. Camera traps are increasingly being used for mul -species monitoring but camera placement and sampling design can strongly influence the frequency with which different species are detected within a community. We were therefore interested in evalua ng whether camera traps provide data that are equally representa ve of habitat use for mul ple species when used as a monitoring tool for both predators and prey.
Our ques on was inspired by the fact that we, like many camera trap-users, placed cameras in a nearly random array in an effort to collect occurrence data on a community of species differing in body size, foraging behavior, and guild. I say nearly random because we used a stra fied random sampling design to place camera traps across two study areas in eastern Washington, USA. But at the microsite-level, we placed each camera trap on a primi ve road or game trail to increase the likelihood of detec ng elusive species (i.e., predators) instead of in truly random loca ons. Given that predator and prey species may use these travel routes and the habitats they bisect differently, we hypothesized that the departure from true random placement may bias detec on and inferred habitat use for some species of interest. Specifically, we predicted that camera trap data would misrepresent habitat associa ons for herbivores (i.e., mule deer, Odocoileus hemoinus) more so than for carnivores (i.e., cougars, Puma concolor) since our placement of cameras was more targeted at the microsite-level for carnivores.
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We used photo-capture data collected by 120 camera traps from June 1 – Sept. 30, 2018 to test our hypothesis. We stra fied our camera placement by eleva on but capped our highest strata at 2,100 meters to avoid sampling alpine habitat primarily for logis cal reasons. We populated single-species, single-season occupancy models with detec on data for cougars and mule deer, respec vely, and fit the species-specific models using a number of covariates we hypothesized would be predic ve of habitat use (e.g., land cover type, eleva on, terrain ruggedness, road density, stream density, etc.). We paired this analysis with resource selec on func on (RSF) analyses using GPS loca on data generated during summer 2018 from 22 cougar and 80 mule deer collars, respec vely.
The GPS collars were deployed within the same study areas as the camera traps with the intent of sampling the same popula ons using mul ple monitoring methods. We included the same covariates in the RSFs as we did the occupancy models, and added a random effect for individual. We ran models for each study area separately and used AIC for model selec on with both the occupancy models and RSFs. Finally, we compared results from the camera trap-based occupancy models to the GPS collar-based RSF models for each species. We expected greater discrepancies in the results from the two methods for a given species if camera trap placement biased the detec on data, and thus es mated habitat associates, of that species.
We found eleva on was an important covariate for both species in both study areas, regardless of the data source and analy cal method used. Interes ngly, we found the rela onship between eleva on and habitat use/selec on differed between methods for both species, most notably with cougars. In the West study area, the camera trap- based occupancy model indicated a quadra c effect of eleva on on cougar habitat use, where probability of use declined at higher eleva ons, whereas the GPS collar-based RSF indicated cougar habitat selec on increased exponen ally with eleva on. This rela onship flipped in the East study area, where the probability of habitat use for cougars increased with eleva on but rela ve probability of selec on decreased with eleva on. As for mule deer in the West study area, we found habitat use and selec on were both posi vely associated with eleva on but that the rela onship was linear with the camera trap data and quadra c with the GPS collar data.
Remotely Wild - Spring 2020 8 SETWG
Although there appears to be a larger discrepancy between the occupancy model and RSF results for cougars compared to those of mule deer, we are hesitant to interpret these results as a species-specific bias in the camera trap data. These discrepancies may be due to a number of sampling issues that have nothing to do with our original concern that camera placement on roads and game trails may bias detec on of some species. Most notably, the GPS collar data indicated that both cougars and mule deer were selec ng for high eleva on habitat in the West study area, well about the 2,100 m cutoff we used for placing camera traps. In addi on, many of the collared animals where restricted to small por ons of our study areas or moved outside our pre-defined study area which le large areas unsampled by GPS collars. As a result, we effec vely sampled different popula ons depending on the sampling method used which may explain the discrepancies we observed. Essen ally, the camera traps allowed us to sample cougars and mule deer at specific loca ons and relate those observa ons to characteris cs of the study areas whereas the GPS-collars allowed us to measure characteris cs associated with the captured cougar and mule deer popula ons.
Although we were unable to fully answer our original research ques on with these data, our results do highlight the fact that how you define and sample your popula on greatly influences the inference you make. We hope to evaluate these sampling issues further as we con nue to collect more camera trap and GPS collar data over the coming years. We plan to expand this analysis to include addi onal species (e.g., wolves, white- tailed deer, elk) and consider how seasonality influences the poten al differences in sampling methods.
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Remotely Wild - Spring 2020 10 SETWG Modeling Carnivore Interactions in Northeastern Oregon Using Activity & Occupancy Patterns
Rylee Jensen1, Joel S. Ruprecht2, Tavis D. Forrester3, Elizabeth K. Orning2, Taal Levi2, Darren E. Clark3
1Utah State University, Department of Wildland Resources 2Oregon State University, Department of Fisheries & Wildlife 3Oregon Department of Fish & Wildlife
In mul -carnivore systems, carnivores must forage and reproduce while compe ng with other carnivores (Linnell and Strand 2000, Hearn et al. 2018) and possibly avoiding intraguild preda on (Polis et al. 1989, Palomares and Caro 1999). Most research has been focused on pairs of compe ng species and it is unclear how carnivores interact with mul ple compe tors, especially in systems with subordinate and apex predators. In this study we assessed the degree of co- occurrence between cougars (Puma concolor), bobcats (Lynx rufus), and coyotes (Canis latrans) in northeast Oregon using occupancy models based on species-specific detec on rates. In addi on, we also accounted for habitat covariates (e.g. terrain ruggedness, canopy cover, distance to water sources, etc.) that may signify preferences for certain areas. Our objec ve was to first explore how these environmental covariates affect the occupancy of these three species, then examine how this influences pairwise species interac ons (i.e. whether occupancy changes as a func on of the presence of compe tors). We also modeled the influence of anthropogenic detec ons on species interac ons. Studying interac ons between these sympatric carnivores as well as their spa otemporal and environmental rela onships may elucidate to what degree these interac ons occur and what factors may contribute to niche par oning or compe on.
Remotely Wild - Spring 2020 11 SETWG
Our two study sites were located in the Blue Mountains of northeastern Oregon. The first, the Starkey Experimental Forest, is a 25,000-acre ungulate-proof enclosure located approximately 30 miles southwest of La Grande, Oregon (Figure 1). It was established in 1989 by the U.S. Forest Service to research the long-term effects of land management prac ces on domes c ca le (Bos tarus) and na ve ungulates like elk (Cervus elaphus) and mule deer (Odocoileus hemionus). The 8- . tall perimeter fence does not inhibit carnivores’ movements in and out of the enclosure, so Starkey con nues to func on as a natural system despite this. Other carnivore species present here apart from our three main study species include black bears (Ursus americanus), mustelids such as striped skunks (Mephi s mephi s), American badgers (Taxidea taxus), and weasels (Mustela spp.), and occasionally red foxes (Vulpes vulpes) and gray wolves (Canis lupus). Common prey species of these carnivores include tree squirrels (Tamiasciurus spp.), woodrats (Neotoma spp.), and snowshoe hares (Lepus americanus).
Fig. 1: . Map and scale of the Starkey Experimental Fig. 2: Map and scale of the Mt. Emily Wildlife Management Forest in northeastern Oregon (from Kie 2013). Unit in northeastern Oregon (from Davidson et al. 2014). The grid displayed from this 2014 study is not the same in our study.
The other study area is the Mt. Emily Wildlife Management Unit (Figure 2), located approximately 12 miles northeast of Starkey. This area covers 770 square miles and has similar wildlife assemblages and dominant habitat features to Starkey. However, one important dis nc on between this study area and Starkey is the presence of the Mt. Emily wolf pack, whose territory encompasses our camera trap grid within this area. Wolves were occasionally sighted in Starkey, but no pack was established within the perimeter fence.
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94 camera traps were placed on a grid with 1 km. spacing in the Starkey Experimental Forest from May-September in 2016 and April-September in 2017. 54 cameras were placed in Mt. Emily from August-November in 2016 and 2017; due to this study area being twice as large as Starkey, cameras on this grid were placed 2 km. apart. Cameras were unbaited and placed approximately 1 . off the ground in Starkey and slightly higher in Mt. Emily. They were commonly deployed on game trails, drainages, stream beds, and ridges to op mize detec on of carnivore species. Photos were then tagged in DigiKam to determine baseline detec on rates for our target species.
Habitat covariates consisted of detec on (observa on/occasion) covariates and occupancy (site) covariates. Detec on covariates are those that influence whether a species is able to be detected by our camera traps at a par cular site (given that they are occupying the site), whereas occupancy covariates are those that influence a species’ use of a site (MacKenzie et al. 2002). We determined seven detec on covariates (road, trail, other, percentage canopy cover, Julian day of deployment, project site, and camera eleva on) and eleven occupancy covariates (year, vegeta on greenness, terrain ruggedness, distance to nearest forest edge, number of wolf detec ons, distance to nearest stream, distance to nearest open road, distance to nearest perennial spring, number of springs within 1 km radius, number of human detec ons, and number of vehicle detec ons).
Covariate layers were generated in ArcMap 10.6.1. All covariates were standardized for analysis and tested for covariance; any two covariates with a covariance >0.5 were omi ed from the same model together. For analysis purposes, we omi ed data from Starkey from April-June to reduce detec on bias with poten ally overlapping the denning season for coyotes. We used 14 survey occasions of 7 days, which began on July 1 for Starkey and August 5 for Mt. Emily.
Binary encounter histories were generated for each of the sample periods. Mul species occupancy models were run in MARK (Rota et al. 2016) to test the effects of various combina ons of environmental covariates and species interac ons. This generated a probability matrix of occupancy in the same sample periods given detec ons. Top models were then selected based on AICc score and weight.
We had four main hypothesis scenarios concerning how habitat covariates and species interac ons would impact occupancy: 1 — Species interac ons alone explain the occupancy of all three species. 2 — Habitat preference supersedes species interac ons in explaining species occupancy. 3 — Habitat preference has a large effect on occupancy, but this is also influenced by species interac ons. 4 — Species occur independently (i.e. habitat preference and spp. interac ons have no effect).
Remotely Wild - Spring 2020 13 SETWG We predict that coyotes and bobcats may exhibit some avoidance behavior of cougars in space and me due to the risk of intraguild preda on (Hass 2009, Koehler & Hornocker 1991). However, there is also the possibility that coyotes may be a racted to cougars to some degree for scavenging opportuni es. Cougars and bobcats may exhibit li le interac on in addi on because of differing habitat and dietary preferences (Hass 2009). Coyotes and bobcats, on the other hand, exhibit a fair amount of dietary overlap and have comparable home range sizes (Witmer and DeCalesta 1986, Litvai s and Harrison 1988, Neale and Sacks 2001), sugges ng niche par oning in areas they co-occur.
Addi onally, we hypothesized three more scenarios concerning human influence on species interac ons: I. Human and vehicle detec ons have no effect on species interac ons II. Human detec ons have a greater effect on species interac ons than vehicle detec ons III. Vehicle detec ons have a greater effect on species interac ons than human detec ons
We expect our results to appear similar to Rota et al.’s (2016) mul species occupancy models involving interac ons between bobcats, coyotes, gray foxes (Urocyon cinereoargenteus), and red foxes (Vulpes vulpes). Separate figures were generated to demonstrate the influence of habitat covariates (Figure 3) and species interac ons (Figure 4). This study found that the spa al distribu on of species was influenced by both factors; for example, coyotes and gray foxes were more likely to co-occur at sites with high human disturbance, but less likely at sites with less human disturbance (Rota et al. 2016). This is why it is crucial for us to include species interac ons as a func on of human- related detec ons.
Fig. 3: . “Marginal occupancy probability of bobcat (Lynx rufus, row 1), coyote (Canis latrans, row 2), grey fox (Urocyon cinereoargenteus, row 3) and red fox (Vulpes vulpes, row 4) in the Mid-Atlan c USA as a func on of the average number of hikers photographed per day (column 1), housing density within a 5 km radius (column 2) and the propor on of area recently disturbed within 5 km (column 3). Solid lines represents the mean posterior distribu ons, and grey ribbons envelop 95% credible intervals. All variables not included in a plot are assumed fixed at their observed mean.” (from Rota et al. 2016) Remotely Wild - Spring 2020 14 SETWG We predict that coyotes and bobcats may exhibit some avoidance behavior of cougars in space and me due to the risk of intraguild preda on (Hass 2009, Koehler & Hornocker 1991). However, there is also the possibility that coyotes may be a racted to cougars to some degree for scavenging opportuni es. Cougars and bobcats may exhibit li le interac on in addi on because of differing habitat and dietary preferences (Hass 2009). Coyotes and bobcats, on the other hand, exhibit a fair amount of dietary overlap and have comparable home range sizes (Witmer and DeCalesta 1986, Litvai s and Harrison 1988, Neale and Sacks 2001), sugges ng niche par oning in areas they co-occur.
Addi onally, we hypothesized three more scenarios concerning human influence on species interac ons: I. Human and vehicle detec ons have no effect on species interac ons II. Human detec ons have a greater effect on species interac ons than vehicle detec ons III. Vehicle detec ons have a greater effect on species interac ons than human detec ons
We expect our results to appear similar to Rota et al.’s (2016) mul species occupancy models involving interac ons between bobcats, coyotes, gray foxes (Urocyon cinereoargenteus), and red foxes (Vulpes vulpes). Separate figures were generated to demonstrate the influence of habitat covariates (Figure 3) and species interac ons (Figure 4). This study found that the spa al distribu on of species was influenced by both factors; for example, coyotes and gray foxes were more likely to co-occur at sites with high human disturbance, but less likely at sites with less human disturbance (Rota et al. 2016). This is why it is crucial for us to include species interac ons as a func on of human- related detec ons.
Our preliminary results indicate that models incorpora ng species interac ons along with the top-ranking occupancy and detec on covariates for each of the three species individually explained species occupancy be er than models that did not incorporate species interac ons. Our top detec on model was non- me varying (i.e. each species had an equal probability of detec on across all sample periods) and included road, trail, and canopy cover as the best combina on of detec on covariates for all species.
Fig. 4: Occupancy probability of bobcat (Lynx rufus), coyote (Canis latrans), grey fox (Urocyon cinereoargenteus) and red fox (Vulpes vulpes) condi onal on the presence and absence of each of the other species. The occupancy probability of the species in each column is condi onal on the presence and absence of the species in each row; for example, the plot in column 1, row 2 represents bobcat occupancy probability condi onal on the presence and absence of coyote. Lines represent posterior means, and ribbons envelope 95% credible intervals. All variables not included in a plot are assumed fixed at their observed mean. Addi onally, condi onal plots are marginalized over the 2 species that did not occur in a plot; for example, the plot in column 1, row 2 sums over all combina ons of grey fox and red fox presence and absence. (from Rota et al. 2016)
Remotely Wild - Spring 2020 15 SETWG Terrain ruggedness and count of wolf detec ons explained both bobcat and coyote occupancy best (individually), while year and count of wolf detec ons were ranked highest for cougars. However, a separate model excluding any covariates for cougars but keeping the top-ranking occupancy covariates for bobcats and coyotes also ranked extremely high, just <1 AICc difference from the previously stated model. This suggests that the top occupancy covariates for cougars may not be significant overall and it is likely that other factor(s) we did not model (e.g. mule deer distribu on/movement) may be driving their occupancy at each of our study sites. More work is also needed to accurately interpret how count of wolf detec ons influences occupancy at camera sites due to significantly more detec ons in the Mt. Emily study area than in Starkey.
Future work will also determine the effect of human and vehicle detec ons on species interac ons at camera sites. Although our study areas have minimal human disturbance aside from roads, carnivores may s ll be a racted or repelled by anthropogenic features; for example, the presence of campers may indicate food sources that some carnivores (especially bold, resilient mesocarnivores like coyotes and bobcats) can take advantage of. Dirt roads in par cular may facilitate movement for our study species (e.g. cougars, Dickson et al. 2005) or present a barrier for movement (e.g. bobcats, Young et al. 2019). Addi onally, each of our three study species can be hunted in northeastern Oregon several or all months of the year, which in turn could create avoidance pa erns around heavily trafficked areas like open roads. Our results may aid managers in accurately determining where these species are
Literature Cited:
Davidson, G.A., Clark, D.A.C., Johnson, B.K., Waits, L.P., and J.R. Adams. 2014. Es ma ng cougar densi es in northeast Oregon using conserva on detec on dogs. Journal of Wildlife Management 78(6): 1104-1114. Dickson, B.G., Jenness, J.S., and P. Beier. 2005. Influence of vegeta on, topography, and roads on cougar movement in southern California. Journal of Wildlife Management 69(1): 264-276. Hass, C.C. 2009. Compe on and coexistence in sympatric bobcats and pumas. Journal of Zoology 278(3): 174–180. Hearn, A. J., Cushman, S. A., Ross, J., Goossens, B., Luke, T., Hunter, B., and D.W. Macdonald. 2018. Spa o-temporal ecology of sympatric felids on Borneo. Evidence for resource par oning? PLoS ONE 13(7), e0200828. Kie, J.G. 2013. A rule-based ad hoc method for selec ng a bandwidth in kernel home-range analyses. Animal Biotelemetry 1:13. Koehler, G.M. and M.G. Hornocker. 1991. Seasonal Resource Use Among Mountain Lions, Bobcats, and Coyotes. Journal of Mammalogy 72(2): 391–396. Linnell, J.D.C. and O. Strand. 2000. Interference interac ons, co-existence and conserva on of mammalian carnivores. Biodiversity Research 6: 169–176. Litvai s, J.A. and D.J. Harrison. 1989. Bobcat–coyote niche rela onships during a period of coyote popula on increase. Canadian Journal of Zoology 67(5): 1180–1188. MacKenzie, D.I., Nichols, J.D., Lachman, G.B., Droege, S., Royle, A., and C.A. Lang mm. 2002. Es ma ng site occupancy rates when detec on probabili es are less than one. Ecology 83: 2248-2255. Neale, J.C.C. and B.N. Sacks. 2001. Resource u liza on and interspecific rela ons of sympatric bobcats and coyotes. Oikos 94(2): 236–249. Palomares, F. and T.M. Caro. 1999. Interspecific Killing among Mammalian Carnivores. The American Naturalist 153(5), 492–508. Polis, G.A., Myers, C.A., and R.D. Holt. 1989. The Ecology and Evolu on of Intraguild Preda on: Poten al Compe tors That Eat Each Other. Annual Review of Ecological Systems 20: 297–330. Rota, C.T., Ferreira, M.A.R., Kays, R.W., Forrester, T.D., Kalies, E.L., McShea, W.J., Parsons, A.W., and J.J. Millspaugh. 2016. A mul species occupancy model for two or more interac ng species. Methods in Ecology and Evolu on 7(10): 1164–1173. Witmer, G.W. and D.S. deCalesta. 1986. Resource use by unexploited sympatric bobcats and coyotes in Oregon. Canadian Journal of Zoology 64(10): 2333–2338. Young, J.K., Golla, J., Draper, J.P., Broman, D., Blankenship, T., and R. Heilbrun. 2019. Space Use and Movement of Urban Bobcats. Animals (Basel) 9(5): 275.
Remotely Wild - Spring 2020 16 SETWG Movement ecology and space-use of mountain lions in wild West Texas
Dana L. Karelus & Patricia Moody Harveson Borderlands Research Institute, Sul Ross State University, PO Box C-21, Alpine, TX, 79832, USA
Understanding the movements of large carnivores across the landscape and their corresponding space use provides us with important details for their management, the management of their prey, for land-use and corridor planning, and for studies on their popula on dynamics and densi es. However, obtaining this informa on can be difficult because large carnivores o en require large areas, occur in low densi es, and can be at odds with humans (Ripple et al. 2014; Pitman et al. 2015). Fragmented landscapes and predator control efforts may make movements within an animal’s home range and among subpopula ons more difficult, thereby poten ally affec ng their overall space-use and intensifying the risks associated with dispersal. Mountain lions (Puma concolor) in West Texas face this scenario.
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West Texas is part of the Chihuahuan Desert; land cover types range from desert scrub to grassland savannah to rugged, rocky terrain and to forests in the higher eleva on mountains. The Chisos Mountains in Big Bend Na onal Park (BIBE) along the U.S.-Mexico border, and the Davis Mountains, approximately 100 km northwest of BIBE, are two such mountain ranges in the southern por on of the region (Figure 1); termed sky islands because the forests in these mountains are fragmented by a sea of desert or grassland. The main subpopula ons of mountain lions in the southern por on of the region occur on these sky islands. Guadalupe Mountains Na onal Park lies approximately another 100 km north of the Davis Mountains and also supports a subpopula on of mountain lions (Harveson et al. 1999), however a major east-west interstate, I-10, runs between the two ranges and likely acts as a barrier to animal movement. In the southern por on of West Texas (south of I-10; Presidio, Jeff Davis, and Brewster coun es), the roads have far less traffic and the human popula on density is very low (es mated at 0.58 people/km2; United States Census Bureau 2018). As with all of Texas, almost all of the land in this region is privately owned and some of the largest ranches in Texas are located in the area. This means that, aside from I-10, roads tend to be a low cause of mortality for mountain lions here. However, humans are s ll their largest cause of mortality. In Texas, mountain lions are considered a non- game species, meaning that they may be trapped or hunted at any me of the year without limit. Indeed, the greatest sources of mortality for mountain lions captured on state or federal proper es in the greater region (Guadalupe Mountains Na onal Park, Carlsbad Caverns Na onal Park, BIBE, and Big Bend Ranch State Park) were lethal predator control and hun ng, mainly when animals went outside the park boundaries onto private lands (Young et al. 2010; Harveson et al. 2012). The associated mountain lion survival rates were among the lowest reported in the U.S (Pi man et al. 1999; Young et al. 2010; Harveson et al. 2012).
Within the state and na onal parks, mountain lions receive at least some protec ons, but because parks are not large enough or in close enough proximity to support the en re mountain lion popula on of West Texas, whole subpopula ons must live en rely on private lands. These animals may face higher mortality risk than those on park proper es, but also poten ally may experience less disturbance from people (i.e. no park visitors) and the land and their prey species are managed differently. These factors not only have survival consequences, but also might affect mountain lion movements and space use, yet no such study had previously been performed on private lands in the region. Addi onally, dispersal among these subpopula ons and others in Mexico and New Mexico is likely cri cal for their gene c health (Holbrook et al. 2012). Therefore, we sought to inves gate these aspects of mountain lion ecology for those in the subpopula on on the private lands in the Davis Mountains and the subpopula on in Big Bend Na onal Park, as well as movements of dispersers throughout the region.
Fig. 1: Map of the study areas in the Davis Mountains and Big Bend Na onal Park in the southern por on of the West Texas region in the United States of America.
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Mountain lion captures for this study occurred from 2011 through 2017, and resulted in the collaring and tracking of 27 subadult and adult individuals (2 females and 2 males in BIBE; 15 females and 8 males in the Davis Mountains). Through the years, various brands of GPS collars were used (Advanced Telemetry Systems G2110L and G2110E collars, Isan , MN; North Star NSG-D1 collar, King George, VA; Vectronic VERTEX Plus GLOBALSTAR, Berlin, Germany) and fix schedules were adjusted. In some cases, collars were set to collect loca ons at more frequent intervals at certain mes. We chose to follow the framework by Calabrese et al. (2016) and used con nuous me movement models and autocorrelated kernel density es mator (AKDE) to analyze and es mate home ranges (Fleming & Calabrese 2017; Noonan et al. 2019). In this way, we were able to account for the inherent autocorrela on among an individual’s loca ons and we avoided discarding data due to the variable fix schedules (Fleming et al. 2018). We used program R (R Core Team 2019) and the package ‘ctmm’ (Fleming & Calabrese 2019) to run our analyses.
Fig. 2: Examples of the path trajectory (top row) and variograms plot (bo om row) from A) a range resident mountain lion (Puma conolor) and B) from a disperser. For resident animals, the semi-variance will reach a general asymptote whereas for dispersers, the semi-variance will con nue to increase.
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Based on variograms of the mountain lions’ movements, we defined 3 subadults as dispersers (Figure 2). These 3 individuals (2 females, 1 male) were all captured in the Davis Mountains and were on rela vely long trips compared to assumed exploratory trips by other subadults in the study. One disperser and 1 subadult on a quick exploratory trip came within at least 2-3 km of I-10, but both turned back at that point. A er approximately 1-2 months of leaving the Davis Mountains (straight-line distances from start to end ranging between approximately 40 km and 135 km), the 2 female dispersers were trapped and killed and the male’s movements stopped abruptly and loca on acquisi on ended; we were unable to retrieve his collar or confirm his fate. We would need more data to examine if I-10 is ac ng as a barrier to mountain lion movements or to examine dispersal in the area in detail; however, our data reaffirm the high mortality risk associated for dispersing individuals.
Fig. 3: An example of 95% u liza on distribu ons (home ranges) from autocorrelated kernel density es mator (AKDE) with 95% confidence intervals based on con nuous me movement models for A) a female and B) a male mountain lion (Puma concolor) in the Davis Mountains, Texas, U.S.A.
As expected, resident female and male adults exhibited different movement and space-use pa erns. Females moved at slower rates and had smaller home ranges than males (Figure 3), a common theme among large carnivores. From the con nuous me movement models, we also obtain es mates of metrics that provide informa on on the general path tortuosity of the animal’s movements and a mescale for the coverage of a constrained area (termed home range crossing me). The models indicated that female and male mountain lions in the study traveled with similar measures of direc onality and with similar home range crossing mes. This indicates that the males covered more space by moving faster than females, but crossed the landscape with similar path pa erns. The highly rugged terrain that mountain lions select for at broad scales in the area (Dennison et al. 2016) could par ally explain the similari es in path direc onality. We are further inves ga ng the movements and space-use of the mountain lions in this wild landscape in West Texas. Our results can poten ally help provide insight for mi ga ng conflict with humans and for insight into poten al dispersal corridors for mountain lions among the sky islands.
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Literature Cited:
Calabrese JM, Fleming CH, Gurarie E. 2016. ctmm: an R package for analyzing animal reloca on data as a con nuous- me stochas c process. Methods in Ecology and Evolu on 7:1124–1132. Dennison CC, Harveson PM, Harveson LA. 2016. Assessing habitat rela onships of mountain lions and their prey in the Davis Mountains, Texas. The Southwestern Naturalist 61:18–27. Fleming CH et al. 2018. Correc ng for missing and irregular data in home-range es ma on. Ecological Applica ons 28:1003–1010. Fleming CH, Calabrese JM. 2017. A new kernel density es mator for accurate home-range and species-range area es ma on. Methods in Ecology and Evolu on 8:571–579. Fleming CH, Calabrese JM. 2019. ctmm: con nuous- me movement modeling. R package version 0.5.6.