Roland C.A.,Denali National Park and Preserve |
Roland C.A.,National Park Service |
Schmidt J.H.,National Park Service
Journal of Biogeography | Year: 2015
Aim: We evaluate whether vascular plant species richness in interior Alaska is highest in the alpine zone. We test the proposition that historical dynamics have influenced the sizes of species pools inhabiting different segments of the landscape by quantifying the contrasting responses of five phytogeographical elements within the flora to changes in elevation and topography. Location: Denali National Park and Preserve, Alaska, USA. Methods: We developed Bayesian hierarchical models for total plant species richness and the richness of five phytogeographical elements with data from a systematic-grid sample containing 1022 plots. We also used rarefaction and extrapolation techniques on these data to estimate species richness for more extensive landscape segments, including across seven elevation bands in the study area. Results: Plot-level species richness had a unimodal response to elevation, reaching its peak in the alpine zone. Overall plant species richness across more extensive areas was also higher in the alpine zone, even though this zone occupies less area overall in interior Alaska. Species richness of Alaska endemic and amphi-Beringian phytogeographical elements showed particularly strong positive responses to elevation, whereas that of the North American and incompletely circumpolar elements declined with elevation. Main conclusions: Our results document a unique pattern in the study of variation in species-pool sizes with elevation, revealing that sparsely vegetated alpine areas contained a larger species pool than adjacent extensive lowlands. This pattern was driven by pronounced increases in phytogeographical elements whose distribution patterns suggest that they evolved or persisted in the region during full-glacial intervals. The persistence of tundra and/or similar open, treeless vegetation in interior Alaska contrasts with the simultaneous periodical elimination of boreal lowland ecosystems in the region. We posit that this has resulted in a regional species pool relatively enriched in alpine species and impoverished in boreal lowland taxa, causing a 'reversed' relationship between species richness and elevation. Increased habitat heterogeneity in high-relief areas of the mountainous landscape are also likely to have contributed to the reported patterns. © 2015 John Wiley & Sons Ltd.
News Article | August 22, 2016
« DOE to invest $16M in computational design of new materials for alt and renewable energy, electronics and other fields | Main | 2017 Range Rover Sport gains new Ingenium 2.0L diesel as option; semi-autonomous driving tech » Denali National Park and Preserve in Alaska, centered on Denali (formerly known as Mount McKinley), the highest mountain in North America, has taken delivery of its first two hydraulic hybrid vehicles from Colorado-based Lightning Hybrids. The shuttle buses, one a Chevrolet model (top above) and the other Freightliner (bottom above), will transport park visitors along the 14-mile paved section of the scenic 92-mile long Denali Park Road at the entrance to the park. The road is the only road in the 6-million-acre park. It runs parallel to the Alaska Range and travels through low valleys and high-mountain passes. The system from Lightning Hybrids is a patented, parallel hydraulic hybrid system that has no electric batteries. Instead, it applies a hydraulic system to the driveline of a vehicle to regenerate braking energy. Hydraulic pumps and a lightweight accumulator brake the vehicle, store the braking energy, and then use that stored energy to provide power to the wheels. In doing so fuel is saved and harmful emissions are cut. The buses were sold by Colonial Equipment Company on the GSA schedule. Lightning Hybrids designs and manufactures the hydraulic hybrid Energy Recovery System (ERS) for medium- and heavy-duty fleet vehicles which provides fuel efficiency by regenerating braking energy, provides safer braking and more power for acceleration, and decreases greenhouse gas emissions. The ERS can be installed on new vehicles as well as retrofitted on vehicles already in service. It is sold through a network of dealers and upfitters.
McIntyre C.L.,Denali National Park and Preserve |
Lewis S.B.,U.S. Fish and Wildlife Service
Journal of Raptor Research | Year: 2016
Migratory Golden Eagles (Aquila chrysaetos) from Alaska winter across a vast region of western North America, much of which is undergoing rapid change from a diversity of indirect and direct human activities. To address recent conservation concerns, we are studying the year-round movements of migratory Golden Eagles from interior and northern Alaska to identify and evaluate potential risks to their survival. We are also developing new survey techniques to estimate population size and trends. As part of our ongoing studies, we observed migrating Golden Eagles in spring and autumn 2014 during field investigations to locate Golden Eagle capture sites in eastern interior Alaska, and in spring 2015 during capture activities. We observed large numbers of Golden Eagles in both spring and autumn, suggesting that the Mentasta Mountains are an important migration corridor for this species. Further, our observations, including 1364 migrating Golden Eagles in October 2014, suggested that the Alaska Golden Eagle population is much larger than is reflected in the only currently available statewide population estimate of 2400 eagles. In combination with historical and contemporary tracking studies, our observations in the Mentasta Mountains provide important new information about Golden Eagle migration in Alaska and stimulate interest in answering fundamental questions about using counts of migrating Golden Eagles to estimate, and detect change in, the population size of Alaska's migratory Golden Eagles. Our observations also provide new information about Rough-legged Hawk migration in Alaska. © 2016 The Raptor Research Foundation, Inc.
Pelto M.,Nichols College |
Capps D.,Denali National Park and Preserve |
Clague J.J.,Simon Fraser University |
Pelto B.,University of Massachusetts Amherst
Hydrological Processes | Year: 2013
Brady Glacier is a large Alaskan tidewater glacier that is beginning a period of substantial retreat. Examination of 27 Landsat and MODIS images from the period 2003 to 2011 indicates that Brady Glacier has a mean equilibrium line altitude (ELA) of 745m and accumulation area ratio (AAR) of 0.40. The zero balance ELA is 600m and equilibrium AAR 0.65. The negative mass balance associated with the increased ELA has triggered thinning of 20-100m over most of the glacier below the ELA from 1948 to 2010. The thinning has caused substantial retreat of seven calving distributary termini of the glacier. Thinning and retreat have led to an increase in the width of and water depth at the calving fronts. In contrast, the main terminus has undergone only minor retreat since 1948. In 2010, several small proglacial lakes were evident at the terminus. By 2000, a permanent outlet river issuing from Trick Lake had developed along the western glacier margin. Initial lake development at the terminus combined with continued mass losses will lead to expansion of the lakes at the main terminus and retreat by calving. The glacier bed is likely below sea level along the main axis of Brady Glacier to the glacier divide. Retreat of the main terminus in the lake will likely lead to a rapid calving retreat similar to Bear, Excelsior, Norris, Portage and Yakutat glaciers. © 2013 John Wiley & Sons, Ltd.
Dortch J.M.,University of Cincinnati |
Owen L.A.,University of Cincinnati |
Caffee M.W.,Purdue University |
Brease P.,Denali National Park and Preserve
Boreas | Year: 2010
Glacial deposits and landforms produced by the Muldrow and Peters glaciers in the McKinley River region of Alaska were examined using geomorphic and 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating (SED) methods to assess the timing and nature of late Quaternary glaciation and moraine stabilization. In addition to the oldest glacial deposits (McLeod Creek Drift), a group of four late Pleistocene moraines (MP-I, II, III and IV) and three late Holocene till deposits ('X', 'Y' and 'Z' drifts) are present in the region, representing at least eight glacial advances. The 10Be TCN ages for the MP-I moraine ranged from 2.5 kyr to 146 kyr, which highlights the problems of defining the ages of late Quaternary moraines using SED methods in central Alaska. The Muldrow 'X' drift has a 10Be TCN age of ∼0.54 kyr, which is ∼1.3 kyr younger than the independent minimum lichen age of ∼1.8 kyr. This age difference probably represents the minimum time between formation and early stabilization of the moraine. Contemporary and former equilibrium line altitudes (ELAs) were determined. The ELA depressions for the Muldrow glacial system were 560, 400, 350 and 190 m and for the Peters glacial system 560, 360, 150 and 10 m, based on MP-I through MP-IV moraines, respectively. The difference between ELA depressions for the Muldrow and Peters glaciers likely reflects differences in supraglacial debris-cover, glacier hypsometry and topographic controls on glacier mass balance. © 2009 The Authors, Journal compilation © 2009 The Boreas Collegium.
Nelson P.R.,Denali National Park and Preserve |
Nelson P.R.,Oregon State University |
Roland C.,Denali National Park and Preserve |
Macander M.J.,ABR Inc. |
McCune B.,Oregon State University
Remote Sensing of Environment | Year: 2013
Spatial variation of available food resources can be difficult to accurately quantify for wide ranging organisms at landscape scales. Lichens with usnic acid, a yellowish pigment, constitute a large portion of caribou winter diet across much of their range. We take a new approach of modeling lichen abundances by capitalizing on unique spectral characteristics of usnic acid lichens. We utilize a recently completed ground reference vegetation data set extending over 12,000km2 in Denali National Park and Preserve, Alaska to model the abundance of usnic lichen and other forage vegetation groups. Spectral signatures were obtained for more than 700 vegetation monitoring plots in Denali from Landsat 7 ETM+ imagery. We fit models of the absolute percent cover of vegetation groups corresponding to caribou diet items, with a focus on lichens. We used non-parametric multiplicative regression to capture the non-linear relationships between vegetation cover and spectral and environmental data. Different groupings of lichen cover were tried as response variables in addition to usnic lichens to see if other lichen color groups were more detectable. The best fitting lichen model was for usnic acid lichens, which explained 37% of the variation using only three predictors (elevation, bands 1 and 7). Elevation had a non-linear, double-humped shaped relationship to usnic lichen abundance while bands 1 and 7 were positively correlated with usnic lichen cover. These results support previous spectroradiometric ground measurements that indicated usnic lichens were distinctive at those wavelengths. Other vegetation groups had models that explained between 31% and 51% of the variation in cover. Maps of estimated abundance of usnic lichens and other vegetation groups covering the northern half of Denali were generated using our models. These maps enable the study of the role of food resources as a continuous resource in winter habitat selection by caribou, rather than assuming food as a coarser, categorical or thematic variable assigned to discrete areas of the landscape as has been done in most previous studies. © 2013 Elsevier Inc.
Libal N.S.,Mississippi State University |
Belant J.L.,Mississippi State University |
Leopold B.D.,Mississippi State University |
Wang G.,Mississippi State University |
Owen P.A.,Denali National Park and Preserve
PLoS ONE | Year: 2011
Given documented social dominance and intraspecific predation in bear populations, the ideal despotic distribution model and sex hypothesis of sexual segregation predict adult female grizzly bears (Ursus arctos) will avoid areas occupied by adult males to reduce risk of infanticide. Under ideal despotic distribution, juveniles should similarly avoid adult males to reduce predation risk. Den-site selection and use is an important component of grizzly bear ecology and may be influenced by multiple factors, including risk from conspecifics. To test the role of predation risk and the sex hypothesis of sexual segregation, we compared adult female (n = 142), adult male (n = 36), and juvenile (n = 35) den locations in Denali National Park and Preserve, Alaska, USA. We measured elevation, aspect, slope, and dominant land cover for each den site, and used maximum entropy modeling to determine which variables best predicted den sites. We identified the global model as the best-fitting model for adult female (area under curve (AUC) = 0.926) and elevation as the best predictive variable for adult male (AUC = 0.880) den sites. The model containing land cover and elevation best-predicted juvenile (AUC = 0.841) den sites. Adult females spatially segregated from adult males, with dens characterized by higher elevations (x̄= 1,412 m, SE = 52) and steeper slopes (x̄ = 21.9°, SE = 1.1) than adult male (elevation: x̄ = 1,209 m, SE = 76; slope: x̄ = 15.6°, SE = 1.9) den sites. Juveniles used a broad range of landscape attributes but did not avoid adult male denning areas. Observed spatial segregation by adult females supports the sex hypothesis of sexual segregation and we suggest is a mechanism to reduce risk of infanticide. Den site selection of adult males is likely related to distribution of food resources during spring.
Nelson P.R.,Oregon State University |
McCune B.,Oregon State University |
Roland C.,Denali National Park and Preserve |
Stehn S.,Denali National Park and Preserve
Journal of Vegetation Science | Year: 2015
Questions: Popular methods to analyse community-trait-environment relationships constrain community patterns by trait and environment relationships. What if some traits are strongly associated with community composition but unrelated to environmental variables and vice versa? We take a different approach, unconstrained by this assumption using non-parametric methods. We applied this technique to lichen (fungal/algal and/or cyanobacterial symbioses) communities across environmental and fire age gradients by measuring richness and cover of four important functional traits: energy generation (type of photosynthetic symbiont), water relations (inferred from growth form), dispersal capability (from vegetative propagules) and microsite specificity (measured by substrate affinity). Location: Denali National Park and Preserve, Alaska, USA. Methods: We ordinated plots in species space and regressed trait and environmental variables against ordination axes, resulting in one- or two-dimensional trait and environment surfaces. We then superimposed these surfaces on the ordination to create a new visual display, the 'hilltop plot', which enabled simultaneous measurement and display of one- and two-dimensional, non-linear community-trait-environment associations. Results: Most traits examined show non-linear relationships with community structure. Fire favoured simple cladoniiform lichens, species with higher vegetative dispersal capacity and specificity to grow on wood, but excluded the 'reindeer' lichens, which had lower cover even more than 20 yrs after fire. Forests had more sorediate lichens than non-forested habitats, whereas high elevation, rocky areas had more green algal and fruticose lichens. Cyanobacterial lichen richness was positively related to shrub cover, while tripartite (cyanobacteria and green algae in a single lichen) and foliose lichen richness was highest in areas with higher moss cover. Conclusions: Different combinations of lichen functional traits peaked along environmental and disturbance gradients, which we interpreted as balancing energy generation, water relations, vegetative dispersal and habitat specificity. Our method of trait-environment-community analysis revealed numerous one- and two-dimensional, non-linear relationships between community composition and functional traits, environmental variables and fire age gradients, which informed mechanisms behind community assembly. Our results indicate non-parametric and non-linear methods of trait-environment-community analysis have the potential to detect patterns that would have been missed using current popular techniques. © 2015 International Association for Vegetation Science.
News Article | December 30, 2015
For years, researchers have been able to track where wolves roam using GPS technology—but that's about it. Without direct observation, scientists have had no way of knowing exactly what these elusive predators are up to in the wild, and what the metabolic cost of different behaviors might be. That has begun to change, however. A team of scientists at UC Santa Cruz has now outfitted wild wolves with a new kind of high-tech collars. Using the same kinds of accelerometers found in smartphones and fitness trackers, these devices tell the scientists not only where the animals are, but also whether they're burning up calories by running or conserving energy while resting, and when. Essentially, the wolves are keeping a diary. “The caloric budget of an animal is sort of its life blood" says Chris Wilmers, an ecology professor at UC Santa Cruz and co-investigator on the project. "If an animal burns more calories than it’s taking in, it’s going to die,” And with too few calories, the animal also can’t reproduce. “We are able to say how many calories the animal burned minute by minute, as its moving across the landscape, carrying out all the functions it needs to do, to live and survive.” It's not just wolves: Scientists around the world are deploying these accelerometers on fish, sharks, and whales to shed light on animal behavior. This is a hot new field, says Caleb Bryce, a doctoral student with Terrie Williams, also a co-investigator on the project. But Bryce is especially interested in the canine carnivores, which are in serious decline. Filling in the gaps of their ecology can help inform conservation efforts, says Bryce. So he wants to understand how prey and landscape features influence wolves' movements. “In order to figure out how much they need to eat to survive, we need to understand behaviors, and how those metabolic costs add up,” says Bryce. Before the team could collect useful information from collared wolves, however, the scientists needed to calibrate the collars in the lab, seeing how calorie burn corresponds to different behaviors—an energetic “signature” for each activity. The problem: how do you get a wild wolf to come in for lab testing? The answer is that it's very difficult—but you can work with a dog, and that's almost as good. Because dogs are the evolutionary descendants of wolves, the information collected from pooches wearing "Smart" collars serves as a useful proxy for wild wolves. Cue Kida, a fluffy 100 pound Alaskan malamute. Bryce recruited Kida and other dogs from scientists and graduate students at Long Marine Lab, in Santa Cruz, California. The dogs ran in an enclosed chamber for about 10 minutes sporting the collar. Air from the chamber was siphoned to an oxygen analyzer. After each session of running, walking, or galloping, Bryce could measure the amount of oxygen depleted from the chamber. That let Bryce calculate the approximate calorie burn for different behaviors. Kida is the longest running member (so to speak) of the study. “She loves having a job,” says Brandy Gale, who owns Kida along with her husband Henry Kaiser. Kaiser adopted Kida at just six months from a malamute rescue organization that finds homes for abandoned pets. Kida is now almost nine years old. “She knows exactly how to get to the lab, and walks through the building right to it,” she says. The dogs are cute, but working with them was not easy, explains Bryce. It took several months to train dogs to run and walk on the noisy and unfamiliar treadmill. Some even pooped and peed on the device. “The mess was spread all over the belt while it was spinning. Yuck!” Years later, the soapy marks used to clean the tread are still present. Though dogs were originally just models for wild wolves, Bryce found some unexpected results from the experiments. Not all dogs are the same, it turns out. Northern breeds were more efficient at running, he says: they can go longer distances while using fewer calories. Bryce and his team are exploring the reasons behind the northern breeds’ surprising efficiency. “We assumed dogs’ metabolic rate was close to that of wolves, because at the time, there wasn’t any wolf metabolic rate published,” Bryce says. Assumptions are risky in science, however so the next step was to work with captive wolves. Eventually, the team tested collars on five captive wolves at a facility in Indiana. The wolves were even more skittish than the dogs. It took over 16 months for train them for the treadmill work. Finally last March, he spent a month deploying the collars on wolves across Denali National Park and Preserve, Alaska. “It’s pretty breathtaking,” says Bryce. “They are truly the symbol of wilderness.” Bryce and his team chose to collar wolves in Denali because it has one of few well-studied wolf populations that is considered natural, says Bryce. This is because there are fewer human impacts on the wolves, such as hunters and roads, than a place like Yellowstone National Park. The park is also huge—it spans more than six million acres—with vastly different prey species and landscape features from east to west. In the west, the land is relatively flat, and wolves eat salmon as a portion of their diet. To the east, wolves have huge mountains to cross, fewer salmon, and more large prey like sheep and moose. The team collared five males each from different packs spread across the park. “The wolves have different things to run up and down, and different prey,” says Bryce. “We want to see if we can detect those differences.” The animals wore the collars for eight months, and Bryce will spend the next several months analyzing the data. The next step is comparing these data to other populations, including those in locations where wolves encounter more human impacts and degraded habitat. Though Denali is remote, even these wolves face human threats, he says. During the course of the study, one of the males was shot when he wandered outside the park boundary. “I was pretty devastated,” Bryce says. Large carnivores are important ecologically,” he says. “They actually help maintain healthy prey populations, unlike populations that are exploding out of control unchecked by predators.” Take the 1995 reintroduction of wolves to Yellowstone, he explained. Before the wolves were brought back, elk and deer ran rampant, munching down all the trees. But with new predators lurking, they had to move more and break into smaller herds. Aspen and willow seedlings had a chance to grow. More trees also meant more food for beavers, whose dams create ponds and habitat. The ripple effect continued and soon fish, small mammals, songbirds, and hawks returned in higher numbers. “It is a classic example of how bringing one focal apex predator back into an ecosystem can restore balance and set things back on the right track,” he says. Members of the Wilmers and Williams labs are deploying this SMART technology on other large mammals, including polar bears, narwhals, and mountain lions. As for Kida, her days of running on treadmills have ended—but she still gets daily seaside hikes with Gale.
News Article | April 29, 2016
Visitors to Denali National Park and Preserve and Yellowstone National Park were twice as likely to see a wolf when hunting wasn't permitted adjacent to the parks, a new study finds.