Lynx Habitat Research Articles

Revealing functional responses in habitat selection of rocky features and rugged terrain by Eurasian lynx (Lynx lynx) using LiDAR data

ContextMany carnivores are attracted to rugged terrain, rocky areas, and conspicuous relief features. However, most of the previous research is limited to general topographical habitat characteristics and rarely consider the effects of microhabitat characteristics.ObjectivesWe used the Eurasian lynx (Lynx lynx) as a model species to investigate the effects of microhabitat characteristics and human infrastructure on habitat selection. We also tested whether there is evidence for a functional response in habitat selection across a large gradient of habitat availability.MethodsWe developed a new approach for detecting rocky outcrops from airborne LiDAR data. In combination with other remote sensing techniques and GPS-telemetry data, we assessed lynx habitat selection and functional responses across two geologically contrasting areas in Europe.ResultsWe detected > 1 million rocky outcrops and confirmed their strong selection by lynx. Lynx also selected steep, rugged, and rocky areas, especially for day-resting sites. Furthermore, lynx avoided paths during the day but selected them and other linear anthropogenic infrastructure during the night, indicating the behaviour-specific impact of human infrastructure. We also observed a functional response in the selection of rocky and rugged areas, as lynx’ selection of such habitats increased with their lower availability. This highlights the importance of preserving such terrains, especially when they are rare in a landscape.ConclusionsOur results highlight the importance of incorporating remote sensing techniques and data on microhabitat features in animal habitat selection research. We also recommend caution when developing new infrastructure for human recreation or promoting its use near geomorphological features and in rugged terrain.

Status assessment of a recently reintroduced eurasian lynx (Lynx lynx) population in the Palatinate Forest, South-West Germany

To reinforce Eurasian lynx populations in central Europe, 20 lynx from Slovakia and Switzerland were translocated to the Palatinate Forest between 2016 and 2020. Using a systematic camera trapping array consisting of 80 camera trapping sites in a 1,000 km² study area located in the centre of the approximately 1,800 km² Palatinate Forest, we aim to describe the status of the population in the final stages of the reintroduction project in winter and spring 2019/20 and 2020/21. We also use our data to provide a first estimate of population density of the newly established population. With an estimate of 0.52 independent individuals per 100 km², population density in the Palatinate Forest was still significantly lower than the densities of well-established reintroduced populations. The number of independent individuals detected in the study area decreased from 15 individuals in 2019/20 to 11 individuals in 2020/21, thus significantly below the number of lynx translocated. The low abundance in the Palatinate Forest can be explained by the dispersal of several individuals to the Vosges (France), which, together with the Palatinate Forest, form a continuous area of suitable lynx habitat of approximately 8,000 km². Our results may thus reflect the status of a young population that can expand over a potentially large area. Nevertheless, in light of the low population density, we strongly recommend a synchronized and harmonized transboundary monitoring program to keep track of the development of this important Franco-German lynx population. In case population density remains low, supportive measures need to be considered.

Modeling range dynamics through time to inform conservation planning: Canada lynx in the contiguous United States

Assessment of historical species range limits is rarely conducted. Yet, understanding where species were distributed in the past is fundamentally important for making informed policy decisions, including assessing species status and recovery in present day and in the context of future environmental change. Here, we provide a case study using a threatened species, Canada lynx, which is the subject of recent conservation policy debate and species recovery planning. We use species distribution models (SDM), combined with historic observations of lynx, to estimate historic southern range limits for the species at year 1900. We then forward project our SDM to estimate lynx vulnerability and likely spatial pattern of range retraction in the future. Our analysis reveals that substantial suitable lynx habitat existed in the past beyond their current range in the contiguous USA, and many extra-limital observations fell within this habitat suggesting relatively broad historic occupancy. This finding implies substantial lynx range contraction over the 20th century and is contrary to recent species status assessment. Moreover, some areas of the contiguous USA that may remain resilient to climate change for lynx in the future, fall outside current species range limits but potentially within historically occupied areas. Our results indicate that future recovery efforts for lynx should be informed by this new evidence regarding species range dynamics through time, including investigating suitability of sites outside current range limits. More broadly, our findings highlight the need for conservation planning and species recovery efforts to consider historical range limits whenever possible.

Integrating animal tracking datasets at a continental scale for mapping Eurasian lynx habitat

AbstractAimThe increasing availability of animal tracking datasets collected across many sites provides new opportunities to move beyond local assessments to enable detailed and consistent habitat mapping at biogeographical scales. However, integrating wildlife datasets across large areas and study sites is challenging, as species' varying responses to different environmental contexts must be reconciled. Here, we compare approaches for large‐area habitat mapping and assess available habitat for a recolonizing large carnivore, the Eurasian lynx (Lynx lynx).LocationEurope.MethodsWe use a continental‐scale animal tracking database (450 individuals from 14 study sites) to systematically assess modelling approaches, comparing (1) global strategies that pool all data for training versus building local, site‐specific models and combining them, (2) different approaches for incorporating regional variation in habitat selection and (3) different modelling algorithms, testing nonlinear mixed effects models as well as machine‐learning algorithms.ResultsTesting models on training sites and simulating model transfers, global and local modelling strategies achieved overall similar predictive performance. Model performance was the highest using flexible machine‐learning algorithms and when incorporating variation in habitat selection as a function of environmental variation. Our best‐performing model used a weighted combination of local, site‐specific habitat models. Our habitat maps identified large areas of suitable, but currently unoccupied lynx habitat, with many of the most suitable unoccupied areas located in regions that could foster connectivity between currently isolated populations.Main ConclusionsWe demonstrate that global and local modelling strategies can achieve robust habitat models at the continental scale and that considering regional variation in habitat selection improves broad‐scale habitat mapping. More generally, we highlight the promise of large wildlife tracking databases for large‐area habitat mapping. Our maps provide the first high‐resolution, yet continental assessment of lynx habitat across Europe, providing a consistent basis for conservation planning for restoring the species within its former range.

Terrestrial and Airborne Lidar to Quantify Shrub Cover for Canada Lynx (Lynx canadensis) Habitat Using Machine Learning

The Canada lynx is listed as a threatened species, and as such, the identification and conservation of lynx habitats is of significant concern. Lynxes require areas with high amounts of horizontal cover made up of ground vegetation. Lidar offers a robust method of quantifying vegetation structure, and airborne lidar has been acquired across large areas of potential lynx habitat. Unfortunately, airborne lidar is often not able to directly measure understory horizontal cover due to occlusion from the upper branches. Terrestrial lidar does directly measure understory horizontal cover and can be used as training data for larger area models using airborne lidar. In this study, we acquired 168 individual terrestrial lidar scans (TLS) across 42 sites in north-central Washington state. We generated metrics from the single-scan TLS plots using depth maps, a digital cover board, and voxels. Using our TLS metrics as the training data for the airborne lidar acquired for the entire Loomis State Forest, we were able to produce a model using xgboost with 85% accuracy. We believe our study shows that single-scan TLS plots can be used effectively to quantify fine-scale forest structure elements relevant to species habitat, to then inform larger area models using airborne lidar.

Climate change, wildfire, and past forest management challenge conservation of Canada lynx in Washington, USA

AbstractThe synergistic effects of climate change, wildfires, fire suppression, and past forest management are challenging efforts to protect and recover Canada lynx (Lynx canadensis) in the North Cascades of Washington, USA. Canada lynx is a threatened species in the United States and a focal species used to gain insights into the structure and function of boreal forest ecosystems. To understand how multiple stressors are influencing lynx populations and the boreal forest in Washington, we developed a spatially explicit carrying capacity model in HexSim using local data on lynx resource selection and life history. We used this model to estimate changes in carrying capacity and population persistence for 3 time steps: year 2000, which represented limited historical wildfire and aggressive fire suppression; year 2013, after nearly 2,000 km2 of wildfires burned about 17% of lynx habitat; and year 2020, after an additional 2,000 km2 of wildfires burned another 15% of lynx habitat in our study area. Fires altered habitat distribution and landscape capacity to support Canada lynx. There was a 66–73% reduction in lynx carrying capacity in our study area because of large, high‐severity fires that have occurred from 2000–2020, despite aggressive fire suppression. This reduction in carrying capacity was concurrent with decreases in the probability of lynx persistence from year 2000 to year 2020 simulations and was most pronounced for simulations that included no immigration and the largest home range size. The negative synergistic influences of long‐term fire suppression, timber harvest, increased drought, longer wildfire seasons, declining mountain snowpack, and increasingly frequent large fires pose considerable challenges to the conservation and recovery of Canada lynx and the boreal forest ecosystem upon which they depend. We discuss an alternative approach to vegetation and fire management to conserve and restore lynx habitat and populations in Washington.

Prerequisites for coexistence: human pressure and refuge habitat availability shape continental-scale habitat use patterns of a large carnivore

ContextAdjustments in habitat use by large carnivores can be a key factor facilitating their coexistence with people in shared landscapes. Landscape composition might be a key factor determining how large carnivores can adapt to occurring alongside humans, yet broad-scale analyses investigating adjustments of habitat use across large gradients of human pressure and landscape composition are lacking.ObjectivesHere, we investigate adjustments in habitat use by Eurasian lynx (Lynx lynx) in response to varying availability of refuge habitats (i.e., forests and rugged terrain) and human landscape modification.MethodsUsing a large tracking dataset including 434 individuals from seven populations, we assess functional responses in lynx habitat use across two spatial scales, testing for variation by sex, daytime, and season.ResultsWe found that lynx use refuge habitats more intensively with increasing landscape modification across spatial scales, selecting forests most strongly in otherwise open landscapes and rugged terrain in mountainous regions. Moreover, higher forest availability enabled lynx to place their home ranges in more human-modified landscapes. Human pressure and refuge habitat availability also shaped temporal patterns of lynx habitat use, with lynx increasing refuge habitat use and reducing their use of human-modified areas during periods of high exposure (daytime) or high vulnerability (postnatal period) to human pressure.ConclusionsOur findings suggest a remarkable adaptive capacity of lynx towards human pressure and underline the importance of refuge habitats across scales for enabling coexistence between large carnivores and people. More broadly, we highlight that the composition of landscapes determines how large carnivores can adapt to human pressure and thus play an important role shaping large carnivore habitat use and distributions.

Canada lynx occupancy and density in Glacier National Park

AbstractProtected areas are the cornerstone of conservation strategies for threatened and endangered species. Because protected areas often are insulated from many anthropogenic threats, and contain substantial topographic relief, they may be particularly important as climatic refugia for cold‐adapted, at‐risk species. Canada lynx (Lynx canadensis) are a cold‐adapted, threatened species, and reach the southern limits of their distribution in the contiguous United States, where they exist in several disjunct populations largely on multiple‐use lands (e.g., national forests). Glacier National Park (GNP) is one of the few, large, protected areas located within Canada lynx range in the contiguous United States, and therefore a potentially important lynx stronghold within the Northern Rockies lynx recovery unit. Despite its potential importance, knowledge of lynx populations within the park is extremely limited. We completed a park‐wide occupancy survey of lynx using an array of motion‐sensitive cameras during summers in 2018–2021. Within a smaller area of the park, we also estimated lynx density by identifying individuals from subtle markings on the inside of the front leg and employing spatially explicit capture‐recapture analysis. Finally, we linked park‐wide predictions of occupancy with local density to estimate lynx population size across GNP. Lynx were distributed across much of the park in summer and occupancy was influenced by a combination of snowshoe hare (Lepus americanus) relative abundance, forest associations, climate, and fire. We were able to successfully identify approximately 75% of lynx captures to individual based on coat markings. Although average park‐wide lynx density was low (1.28/100 km2) compared to populations in the core of the range, park‐wide abundance was substantial for this threatened predator (52; 95% CI = 30–92). Based on our results, we propose that GNP should be considered as a potentially important area for lynx habitat refugia in a warming climate. Moreover, our ability to rapidly assess distribution and density using camera deployments in summer could be useful for long‐term monitoring and recovery assessment.

Effects of compound disturbance on Canada lynx and snowshoe hare: Wildfire and forest management influence timing and intensity of use

Wildfires are increasing in scale and impact on the landscape, altering large amounts of wildlife habitat and forest ecosystems. The reduction of fuels through forest management is considered a primary way to reduce the extent and severity of wildfires before they occur but may lead to a decrease in tree density prohibitive of some species’ habitat. Alternatively, management actions undertaken after a fire may speed the trajectory of burned areas back into quality habitat but may also impede this development if the wrong type of treatment is undertaken. Thus, information on how different management actions, applied either pre- or post-fire, can influence the timing of a burned area’s return to suitable habitat will help managers conserve species on the landscape. Our study aims to understand how a rare carnivore, Canada lynx (Lynx canadensis), uses stands managed with different silviculture actions at different times relative to wildfire. We used GPS locations from 39 individual lynx collected from 2004 to 2015 to examine the response of lynx to wildfire compounded by active forest management, where time since fire at time of use ranged from 1 to 27 years. To understand the drivers behind lynx use of wildfires, we also focused on the primary prey of Canada lynx, snowshoe hares (Lepus americanus), using pellet counts across a similar range of post-fire treatment types in fires between 22 and 28 years old. We also assessed vegetation recovery and forest structure over time since wildfire using remotely sensed data and field measurements. We found that lynx intensity of use differed based on timing and type of management action, with the greatest lynx use ∼25 years after a wildfire managed with post-fire regeneration cuts (removal of the majority of the canopy). Lynx use was likely driven by hare abundance, which was also highest in post-fire regeneration cuts, characterized at time of use by dense lodgepole pine stands. We conclude that managing landscapes with a mosaic of active (pre- and post-fire treatments) and passive (hands-off) management will best conserve a desirable range of lynx habitat in an increasingly fire-impacted landscape.

Eurasian lynx density and habitat use in one of Europe’s strongholds, the Romanian Carpathians

Abstract The Eurasian lynx (Lynx lynx) faces population declines in the western part of its range, and its ecological requirements are poorly understood in the eastern part of its range. The Romanian Carpathians harbor an intact large carnivore community, in which lynx co-occur with bears (Ursus arctos), wolves (Canis lupus), and humans (Homo sapiens), with which they potentially compete for ungulate prey. We provide a science-based estimate of lynx density and habitat use, combining non-invasive monitoring techniques (camera trapping) with spatially explicit capture-recapture models (SECR) in the Southern Carpathians of Romania. We sampled 59 and 76 trap stations during two monitoring sessions (winter and autumn), identified at least 30 individuals, from which we reconstructed encounter histories for 23 individuals. SECR modeling resulted in similar density estimates between winter and autumn (1.6 ± 0.39 SE and 1.7 ± 0.38 SE lynx/100 km2, respectively), but the cumulative number of lynx detected reached the asymptote faster during autumn, suggesting that monitoring prior to the mating season is preferable. Density varied within and across sessions with topography (slope), percent forest cover, and landscape heterogeneity (i.e., agricultural mosaic). Density hotspots shifted between low-altitude agricultural mosaic during winter and more rugged, mid-altitude forest stands during autumn. Estimated densities of lynx in the Romanian Carpathians are higher than those reported in the Alps or Slovak Carpathians, highlighting the importance of this population as a source both for natural recolonization and recent reintroduction programs. When used in an SECR framework, camera trapping is an efficient method for assessing spatial and temporal variation in lynx population density in the remote Romanian Carpathians. We recommend this methodology for improving lynx population estimates and to monitor lynx population trends nationwide.

Improved prediction of Canada lynx distribution through regional model transferability and data efficiency.

The application of species distribution models (SDMs) to areas outside of where a model was created allows informed decisions across large spatial scales, yet transferability remains a challenge in ecological modeling. We examined how regional variation in animal‐environment relationships influenced model transferability for Canada lynx (Lynx canadensis), with an additional conservation aim of modeling lynx habitat across the northwestern United States. Simultaneously, we explored the effect of sample size from GPS data on SDM model performance and transferability. We used data from three geographically distinct Canada lynx populations in Washington (n = 17 individuals), Montana (n = 66), and Wyoming (n = 10) from 1996 to 2015. We assessed regional variation in lynx‐environment relationships between these three populations using principal components analysis (PCA). We used ensemble modeling to develop SDMs for each population and all populations combined and assessed model prediction and transferability for each model scenario using withheld data and an extensive independent dataset (n = 650). Finally, we examined GPS data efficiency by testing models created with sample sizes of 5%–100% of the original datasets. PCA results indicated some differences in environmental characteristics between populations; models created from individual populations showed differential transferability based on the populations' similarity in PCA space. Despite population differences, a single model created from all populations performed as well, or better, than each individual population. Model performance was mostly insensitive to GPS sample size, with a plateau in predictive ability reached at ~30% of the total GPS dataset when initial sample size was large. Based on these results, we generated well‐validated spatial predictions of Canada lynx distribution across a large portion of the species' southern range, with precipitation and temperature the primary environmental predictors in the model. We also demonstrated substantial redundancy in our large GPS dataset, with predictive performance insensitive to sample sizes above 30% of the original.

Felid bedrooms with a panoramic view: selection of resting sites by Eurasian lynx (Lynx lynx) in a karstic landscape

Eurasian lynx (Lynx lynx) is a crepuscular-nocturnal carnivore and mostly spends daytime resting. Although resting sites represent an important part of the lynx habitat and can be negatively affected by human activities, it is still poorly known how lynx select these sites, especially in regions with rugged topography characteristic for much of the species’ range. We analysed microscale habitat selection of lynx resting sites at the home-range level in a karstic landscape of the Dinaric Mountains, Slovenia, using a use-availability study design. We also searched for differences in the selection of resting sites in respect to the presence of ungulate kills, which often limit the available resting sites during the prey-consumption period. Using generalised linear mixed models (GLMM), we tested which environmental features and human infrastructure are important for lynx when choosing resting sites. Lynx selected mountain ridges and hilltops, as well as locations with steeper slopes and lower local visibility. Such locations likely provide concealment from potential danger or prey and, at the same time, offer good overview of the surroundings. There was also a tendency to avoid forest cabins and to select rocky terrain and southern exposures, but support in the data for this was lower. When lynx were not limited by the presence of fresh kill, the selection tended to be stronger, but the differences were not significant, except for visibility, which was lower at resting sites near prey remains. Results likely reflect high availability of suitable resting sites in a rugged terrain of karstic landscape. Animals are often most vulnerable during sleep, thus the resting site should ideally provide them with cover to reduce exposure and at the same time give them good overview of the surroundings to detect any approaching danger. We used snow tracking and GPS telemetry, for the first time in combination with data from activity sensors, to reliably determine resting sites of Eurasian lynx in a rugged karstic landscape. We showed how lynx face the trade-off of the need to be concealed, yet at the same time attain good view, by selecting structured microhabitats on top of the ridges and on steep slopes. Our results also suggest that in the regions with rugged terrain the influence of human infrastructure might be lower compared to the study areas of previous research.

A specialized forest carnivore navigates landscape-level disturbance: Canada lynx in spruce-beetle impacted forests

Abstract Canada lynx (Lynx canadensis) occupy cold wet forests (boreal and subalpine forest) that were structured by natural disturbance processes for millennia. In the Southern Rocky Mountains, at the species’ southern range periphery, Canada lynx habitat has been recently impacted by large-scale disturbance from spruce beetles (Dendroctonus rufipennis). This disturbance poses a challenge for forest managers who must administer this novel landscape in ways that also facilitate timber salvage. To aid managers with this problem, we instrumented Canada lynx with GPS collars to document their selection of beetle impacted forests at spatial scales that spanned from landscapes to movement paths. We used a use-availability design based on remotely-sensed covariates to evaluate landscape- and path-level selection. We evaluated selection at the home-range scale in beetle-kill areas based on vegetation plots sampled in the field to quantify forest structure and composition. We found that across all scales of selection, Canada lynx selected forests with a higher proportion of beetle-kill trees that were generally larger in diameter than randomly available. Within home ranges, Canada lynx selected forests with greater live components of subalpine fir and live canopy of Engelmann spruce. During winter, Canada lynx exhibited functional responses, or disproportionate use relative to availability, for forest horizontal cover, diameter of beetle killed trees, live canopy of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa), and additive use (and consistent selection) for relative density of snowshoe hares and density of subcanopy subalpine fir 3–4.9 in. (7.6–12.4 cm) in diameter. We discuss our results in the context of balancing resource needs of Canada lynx with the desire to salvage timber in beetle-impacted forests.

A specialized forest carnivore navigates landscape-level disturbance: Canada lynx in spruce-beetle impacted forests

Canada lynx (Lynx canadensis) occupy cold wet forests (boreal and subalpine forest) that were structured by natural disturbance processes for millennia. In the Southern Rocky Mountains, at the species’ southern range periphery, Canada lynx habitat has been recently impacted by large-scale disturbance from spruce beetles (Dendroctonus rufipennis). This disturbance poses a challenge for forest managers who must administer this novel landscape in ways that also facilitate timber salvage. To aid managers with this problem, we instrumented Canada lynx with GPS collars to document their selection of beetle impacted forests at spatial scales that spanned from landscapes to movement paths. We used a use-availability design based on remotely-sensed covariates to evaluate landscape- and path-level selection. We evaluated selection at the home-range scale in beetle-kill areas based on vegetation plots sampled in the field to quantify forest structure and composition. We found that across all scales of selection, Canada lynx selected forests with a higher proportion of beetle-kill trees that were generally larger in diameter than randomly available. Within home ranges, Canada lynx selected forests with greater live components of subalpine fir and live canopy of Engelmann spruce. During winter, Canada lynx exhibited functional responses, or disproportionate use relative to availability, for forest horizontal cover, diameter of beetle killed trees, live canopy of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa), and additive use (and consistent selection) for relative density of snowshoe hares and density of subcanopy subalpine fir 3–4.9 in. (7.6–12.4 cm) in diameter. We discuss our results in the context of balancing resource needs of Canada lynx with the desire to salvage timber in beetle-impacted forests.

Movement patterns and habitat selection during dispersal in Eurasian lynx

Natal dispersal affects the gene flow, distribution, dynamics and social structure of a population. In many solitary mammals, dispersal is often male-biased, while females may remain philopatric. For the Eurasian lynx (Lynx lynx), dispersal distances vary greatly and may be explained by sex or by habitat characteristics, such as fragmentation. Juvenile lynx habitat selection during dispersal has not been studied before, but resident lynx select heterogeneous forested habitats and avoid human settlements and infrastructure through distinct temporal activity patterns. We studied movement patterns and habitat selection during the dispersal of 22 Eurasian lynx (7 females, 15 males) in Finland. We found no differences between the sexes in the onset age, duration, distance, route or route linearity. Dispersal took place mostly during the evening and at night but also during the day. Of the four most used habitats, the mixed forests and transitional woodlands were used more frequently than would be expected according to their availability, and conifer forests and fields less than would be expected. Housing and other human infrastructure, including roads, were the least frequently used categories. There was a highly significant difference between the used and available habitats in general. The lynx selected the habitat more carefully during the day than during the night.

Will Lynx Lose Their Edge? Canada Lynx Occupancy in Washington

ABSTRACTPopulations of species located at southern range edges may be particularly vulnerable to the effects of climate change as warming temperatures and subsequent changes to ecosystems exceed species‐specific tolerances. One such species is Canada lynx (Lynx canadensis), a cold‐adapted mesocarnivore that maintains a large core population in Alaska, USA, and Canada but exists within several peripheral populations in the contiguous United States. Increases in temperature, declines in snow pack, and climate‐influenced increases in fire frequency and intensity, could negatively affect lynx populations, threatening their long‐term persistence in the continental United States. Despite these threats, our understanding of broad‐scale effects on lynx occupancy and the extent of current lynx distribution in many of these peripheral populations is minimal. We conducted an occupancy survey of lynx in Washington, USA, using a spatially extensive camera‐trapping array covering 7,000 km2 of potential lynx habitat. We used the resulting database of detection data to develop single‐season occupancy models to examine the abiotic and biotic effects on current lynx occupancy and predict future lynx distribution based on climate change forecasts. Our results show lynx occupancy across the Washington landscape is restricted and dictated largely by abiotic factors, disturbance regimes, and distance from source populations in Canada. Predictions of future distribution suggest lynx will be increasingly challenged by climatic changes, particularly at the southern and lower elevation portions of their range in Washington. Our results paint an alarming picture for lynx persistence in Washington that is relevant to current deliberations regarding lynx delisting from the Endangered Species Act. Our simple camera design was a highly effective method for surveying lynx across broad spatial scales, and could be a key monitoring tool for lynx that is easy to implement by researchers and government agencies. © 2020 The Wildlife Society.

Predicting forest understory habitat for Canada lynx using LIDAR data

ABSTRACTCanada lynx (Lynx canadensis) is a federally threatened species in the contiguous United States. Within National Forests covered by the Northern Rockies Lynx Management Direction, Federal land managers must consider the effect of management activities on Canada lynx habitat. A common method to assess Canada lynx habitat used by the U.S. Forest Service is to measure horizontal cover using a cover board. We used field measurements and airborne Light Detection and Ranging (LIDAR) metrics to test beta regression models that predict estimates of horizontal cover on the Nez Perce–Clearwater National Forest, Idaho, USA, 2009–2015. We also investigated the effect on model predictions when the cover board was blocked by the main stem of a tree. Model fit statistics for normalized root mean square errors (RMSE%) were 30.8–33.7% and pseudo‐R2 ranged from 0.64 to 0.71. Using independent validation data, model performance statistics for RMSE% were 24.6–33.5% and R2 ranged from 0.51 to 0.69. We found that removing cover board measurements where the main stem of a tree blocked >75% of the cover board produced the best model statistics. These models can be applied across LIDAR extents resulting in maps of horizontal cover estimates, which may be used in assessing effects of management activities on Canada lynx habitat. © 2019 The Wildlife Society.

The role of forest canopy cover in habitat selection: insights from the Iberian lynx

Habitat selection models for woodland species usually consider forest attributes derived from land cover maps, such as an area covered by forests or distance to forest edge, but canopy cover is less frequently used as a predictor. We evaluated the effect of including forest canopy cover data in habitat selection models for woodland species using the endangered Iberian lynx as a case study. We considered four canopy cover classes for both conifer and broadleaved forests, together with other land cover predictors, and analyzed a large telemetry (GPS-GSM collars) dataset. The model that included forest canopy cover outperformed, both in predictive power and in conservation management insights, the model that only used forest area. The effect of forest canopy cover on lynx habitat selection was especially strong for broadleaved forests; an increased tree cover in these forests consistently translated into significantly lower selection probabilities. Open broadleaved forests were found to clearly be the most preferred habitat. By contrast, the habitat model without canopy cover data indicated that broadleaved forests were significantly less preferred than shrublands and mountain olive groves, which may mislead conservation management actions. We conclude that habitat selection models for woodland species should consider forest canopy cover as a relevant candidate predictor as it can capture important factors influencing habitat use, such as understory vegetation abundance or prey availability. Recent developments on remote sensing technologies will increase the availability of spatially continuous information on canopy cover, facilitating a more widespread use of vegetation structural variables in habitat modeling and hence improving the conservation planning value of these models.

Navigating fragmented landscapes: Canada lynx brave poor quality habitats while traveling.

Anthropogenic and natural habitat fragmentation inhibit movement of animals through landscapes. An important challenge for connectivity conservation is determining which conditions facilitate or limit movements, so that these areas can be prioritized for protection or restoration. We examine Canada lynx Lynx canadensis habitat connectivity in the fragmented North Cascade Mountains of Washington, as an example of a highly mobile species that is specialized both on prey and in habitat needs. We identify lynx Habitat Concentration Areas based on Core Habitat Models, parameterize resistance surfaces from our Matrix Habitat Model, and develop linkages of habitat lynx use to move between patches of high quality habitat. We identify a number of linkages for lynx comprised of habitat conditions that differed from high quality core patches identified from our habitat modeling. Radio‐locations from lynx confirm lower‐quality habitats of low resistance to movement were used by traveling lynx. Our results thus suggest traveling lynx do indeed use a much broader range of habitats than do lynx moving within core areas. For lynx in the North Cascades, our results show that maintaining connectivity will require preserving habitats and linkages that would previously have been deemed unsuitable for lynx. Maintaining connectivity for lynx is particularly important given the many recent large wildfires in this region that have reduced the number of mature forest stands that form prime habitat for lynx. Policy implications. Our results strongly suggest that habitat connectivity models should be based on empirical information of animal location data and focused on matrix habitat analysis. Traveling predators use a wide suite of habitats, resulting in more and broader linkage zones that should inform conservation efforts. Failure to identify these areas of functional connectivity could result in the oversight of usable linkage zones, leaving them without protection and vulnerable to degradation.

Understanding and predicting habitat for wildlife conservation: the case of Canada lynx at the range periphery

AbstractEcologists and managers are motivated to predict the distribution of animals across landscapes as well as understand the mechanisms giving rise to that distribution. Satisfying this motivation requires an integrated framework that characterizes multi‐scale habitat use and selection, as well as builds predictive models such as resource selection functions. However, the assumption of constant habitat use or selection is often made in such analyses, which ignores the possibility that individuals experiencing different conditions might respond differently. Assessing functional responses in habitat use evaluates how animal behavior changes with differing environmental conditions, which has basic and applied utility. Here, we combined these ideas into an integrated process that characterizes habitat relationships, predicts habitat, and assesses behavioral differences with changing environmental conditions. Our species of interest was Canada lynx (Lynx canadensis) in the Northern Rocky Mountains, which is a rare and federally threatened forest carnivore. Through our process, we developed multi‐scale predictions of lynx distribution and learned that across scales and seasons, lynx use more mature, spruce‐fir forests than any other structure stage or species. Intermediate snow depths and the distribution of snowshoe hares (Lepus americanus) were the strongest predictors of where lynx selected their home ranges. Within their home ranges, female and male lynx increasingly used advanced regeneration forest structures as they became more available (up to a maximum availability of 40%). These patterns supported the bottom‐up mechanisms regulating Canada lynx in that advanced regeneration generally provides the most abundant snowshoe hares, while mature forest is where lynx appear to hunt efficiently. However, lynx exhibited decreasing use of stand initiation structures (up to a maximum availability of 25%). Land managers have an opportunity to promote lynx habitat in the form of advanced regeneration, but are required to go through the stand initiation phase. Thus, managers can apply the relative proportions of forest structure classes along with our response curves to inform landscape actions (e.g., timber harvest) targeted at facilitating the forest mosaic used and selected by Canada lynx. Collectively, the insights gleaned from our approach advance habitat conservation efforts and consequently are of broad utility to applied ecologists and managers.