Carl A Roland

• M.S.
• Plant ecologist at Denali National Park and Preserve

The ranges of black and white spruce are largely sympatric, suggesting both species have similar climate requirements. The two species, however, are highly segregated across the landscape with black spruce most common on nutrient‐poor sites with cold, poorly drained soils and white spruce more common on productive sites with warmer, well‐drained so...

Wildfire frequency and extent is increasing throughout the boreal forest-tundra ecotone as climate warms. Understanding the impacts of wildfire throughout this ecotone is required to make predictions of the rate and magnitude of changes in boreal-tundra landcover, its future flammability, and associated feedbacks to the global carbon (C) cycle and...

Boreal forest and tundra ecosystems are undergoing rapid climatic and environmental changes with consequences for ecosystem structure, function, and services. Although riparian zones occupy a small footprint within subarctic landscapes, they have disproportionately high value as foci of hydrological processes, biogeochemical cycling, ecological dis...

A prominent hypothesis in ecology is that larger species ranges are found in more variable climates because species develop broader environmental tolerances, predicting a positive range size-temperature variability relationship. However, this overlooks the extreme temperatures that variable climates impose on species, with upper or lower thermal li...

Inferences about the mechanisms of distributional change are often made from simple assessments of variation in the geographical positions of populations. However, direct assessments of species' responses to local habitat change may be necessary for proper understanding of the drivers of distributional dynamics. Amplified climate warming is inducin...

The Alaskan landscape has undergone substantial changes in recent decades, most notably the expansion of shrubs and trees across the Arctic. We developed a Bayesian hierarchical model to quantify the impact of climate change on the structural transformation of ecosystems using remotely sensed imagery. We used latent trajectory processes to model dy...

The Alaskan landscape has undergone substantial changes in recent decades, most notably the expansion of shrubs and trees across the Arctic. We developed a dynamic statistical model to quantify the impact of climate change on the structural transformation of ecosystems using remotely sensed imagery. We used latent trajectory processes in a hierarch...

Climate change is increasing the frequency and intensity of drought events in many boreal forests. Trees are sessile organisms with a long generation time, which makes them vulnerable to fast climate change and hinders fast adaptations. Therefore, it is important to know how forests cope with drought stress and to explore the genetic basis of these...

Permafrost formation and degradation creates a highly patchy mosaic of boreal peatland ecosystems in Alaska driven by climate, fire, and ecological changes. To assess the biophysical factors affecting permafrost dynamics, we monitored permafrost and ecological conditions in central Alaska from 2005 to 2021 by measuring weather, land cover, topograp...

Hungry for a little plant diversity? Let us mix some up! First, we gather available ingredients—a bit of soil, a few nutrients, and a selection of nearby plants. Then, we add them together, pour them onto a landscape and let our concoction sit. Sound easy enough? But wait… was that soil we used too acidic? Did we add enough liquid? Was our landscap...

Aim Climate change is occurring at accelerated rates in high latitude regions such as Alaska, causing alterations in woody plant growth and associated ecosystem patterns and processes. Our aim is to assess the magnitude and speed that climate‐induced changes in woody plant distribution and volume may be reduced and/or slowed by relatively static la...

Merging robust statistical methods with complex simulation models is a frontier for improving ecological inference and forecasting. However, bringing these tools together is not always straightforward. Matching data with model output, determining starting conditions, and addressing high dimensionality are some of the complexities that arise when at...

Significance Black spruce is the dominant tree species in boreal North America and has shaped forest flammability, carbon storage, and other landscape processes over the last several thousand years. However, climate warming and increases in wildfire activity may be undermining its ability to maintain dominance, shifting forests toward alternative f...

A summary of aspen phenology observations in relation to annual variation in weather made by Central Alaska Vegetation Monitoring program of the National Park Service, circa 2005 - 2016.

Climate change is impacting both the distribution and abundance of vegetation, especially in far northern latitudes. The effects of climate change are different for every plant assemblage and vary heterogeneously in both space and time. Small changes in climate could result in large vegetation responses in sensitive assemblages but weak responses i...

Quantitative studies of regional variation in plant diversity across eastern Beringia (northern Alaska and adjacent areas) are lacking due to an absence of datasets of sufficient scale and scope. We interrogated a landscape‐scale plant diversity dataset collected across two regions of interior Alaska with different disturbance, topographic, and cli...

Gridded historical climate products (GHCPs) are employed with increasing frequency when modeling ecological phenomena across large scales and predicting ecological responses to projected climate changes. Concurrently, there is an increasing acknowledgement of the need to account for uncertainty when employing climate projections from ensembles of g...

Previous research indicates that the effects of climate warming, including shrub expansion and increased fire frequency may lead to declining lichen abundance in arctic tundra and northern alpine areas. Lichens are important forage for caribou (Rangifer tarandus), whose populations are declining throughout most of North America. To clarify how lich...

Geary's contiguity ratio (i.e., Geary's c ) is used to measure spatial autocorrelation in data with discrete spatial support. Calculation of Geary's c depends on the observed spatial data and a set of dyadic weights that are generally defined based on the proximity of observations to each other, but can be generalized to accommodate geographic dist...

Climate change is altering disturbance regimes globally, including their frequency and severity, with strong evidence of shifts in the ecological communities recovering following disturbance. In boreal forests, intensification of wildfire regimes is driving altering regeneration outcomes in some regions, for instance from black spruce (Picea marian...

Protocol and standard operating procedures for recording observations of aspen phenology in the Central Alaska Network of the National Park Service in interior Alaska, U.S.A.

Recent findings of peak plant species diversity occurring in alpine tundra in Alaska may reflect the filtering of the regional species pool during Pleistocene Epoch cold periods. Specifically, herbaceous plant groups and those with far northern geographic distributions centered in Beringia may have persisted coincident with repeated diminution of t...

High latitude regions are warming rapidly with important ecological and societal consequences. Utilizing two landscape‐scale data sets from interior Alaska, we compared patterns in forest structure in two regions with differing fire disturbance, topography, and summer climate norms. Our goal was to evaluate a set of hypotheses concerning possible w...

The expansion of shrubs and trees across high‐latitude ecosystems is one of the most dramatic ecological manifestations of climate change. Most of the work quantifying these changes has been done in small areas and over relatively recent time scales. These land‐cover transitions are highly spatially variable, and we have limited understanding of th...

The negative growth response of North American boreal forest trees to warm summers is well documented and the constraint of competition on tree growth widely reported, but the potential interaction between climate and competition in the boreal forest is not well studied. Because competition may amplify or mute tree climate‐growth responses, underst...

Many habitat selection studies have focused on the importance of spatiotemporal scales and sample size, yet often hidden within is a trade-off between using more animal locations versus more predictive covariates. Few have evaluated the outcome of choosing between these two different paths even though the trade-off can have significant impacts on t...

Many plant species reproduce by cloning if environmental conditions are unfavorable for sexual reproduction. To test the alternative hypotheses, whether cloning is an “exit strategy” or caused by selection, clonal growth in white spruce (Picea glauca (Moench) Voss) was investigated in three stands in Alaska, each consisting of a core (closed forest...

Supplementary material for the following paper: Modeling high-latitude summer temperature patterns using physiographic variables

In light of increasing threats to global biodiversity, identifying the patterns in and drivers of variation in species composition along the environmental gradients in understudied regions is crucial for understanding ecosystem vulnerability and resilience. Terrestrial plant communities of interior Alaska are dominated by three major groups of prim...

Recent investigations of high-resolution temperature patterns employing dense observational networks have improved our understanding of fine-scale climatic influence on hydrological and ecological processes. Few of these investigations, however, have focused on high-latitude environments. In this study – one of the first to evaluate drivers of fine...

Vertebrate populations throughout the circumpolar north often exhibit cyclic dynamics, and predation is generally considered to be a primary driver of these cycles in a variety of herbivore species. However, weather and climate play a role in entraining cycles over broad landscapes and may alter cyclic dynamics, although the mechanism by which thes...

The National Park Service has been monitoring dust palliative (CaCl2) applications and chloride in roadside soil solution and surface water for 13 years along the length of the Denali Park Road in interior Alaska. In this report, we describe the results of this program, focusing on the spatial and temporal patterns of chloride occurrence and its ef...

One of the central goals of the field of population ecology is to identify the drivers of population dynamics, particularly in the context of predator–prey relationships. Understanding the relative role of top-down versus bottom-up drivers is of particular interest in understanding ecosystem dynamics. Our goal was to explore predator–prey relations...

Climate warming has initiated changes to vegetation across subarctic North America with potential to dramatically alter the distribution of biodiversity of vascular plants, mosses, and macrolichens. However, landscape-scale studies of the patterns and drivers of species richness in this region are scarce, raising the possibility that dramatic chang...

Climate warming in northern latitudes has led to an intensification of disturbance by wildfire. Little is known about the effects of fire on tundra vegetation. Changes in vegetation composition could have important implications for carbon cycling , and may feedback positively or negatively to future climate change (Randerson et al., 2006). Our stud...

The growth response of boreal forest trees to projected changes in climate will have wide ranging and cascading impacts on disturbance regimes, climate feedbacks, carbon storage, and habitat ranges for flora and fauna. Recent findings in Alaska suggest the boreal biome is shifting in response to changes in climate. It is unlikely such a shift will...

We remeasured a classic chronosequence study in the subalpine zone of the Alaska Range to evaluate how plant community attributes have changed across a set of different-aged terraces over a 54-yr period (1958–2012). Our work focused on whether the tempo and trajectory of successional development described in the original study have changed over thi...

Despite predictions of poleward and upslope shifts in the distribution of breeding passerines under climate change, studies often report variable responses with some species shifting opposite of the expected direction and others showing range stability. While changes in climate could affect distribution directly, passerines show strong preferences...

doi: 10.1639/0747-9859-32.4.195

Increases in terrestrial primary productivity across the Arctic and northern alpine ecosystems are leading to altered vegetation composition and stature. Changes in vegetation stature may affect predator-prey interactions via changes in the prey's ability to detect predators, changes in predation pressure, predator identity and predator foraging st...

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‐p...

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 i...

Mast-seeding conifers such as Picea glauca exhibit synchronous production of large seed crops over wide areas, suggesting climate factors as possible triggers for episodic high seed production. Rapidly changing climatic conditions may thus alter the tempo and spatial pattern of masting of dominant species with potentially far-reaching ecological co...

In 2005 Denali National Park and Preserve received a donation of many hundreds of photographs taken from the backseat of a two-seater airplane by Dr. Fred Dean, emeritus professor of wildlife biology at the University of Alaska. Dr. Dean had taken these photographs in the summers of 1975-6 as part of a project to produce the first land-cover map o...

We investigated habitat attributes related to the occupancy of the globally rare and endangered epiphytic lichen, Erioderma pedicellatum, in a newly discovered (2009) population center in Denali National Park and Preserve (DNPP), Alaska. We measured forest, tree and epiphytic lichen community characteristics on eighty-five systematically selected p...

We present a substantially revised and updated bryophyte flora for the 2.4 million ha Denali National Park and Preserve (DNPP) based on wide-ranging field investigations conducted over the period 2001–2011. We visited 39 inventory sites and 45 vegetation monitoring study areas within DNPP, increasing the number of bryophyte taxa previously known by...

We conducted a vascular plant inventory of six National Park Service units in southwestern and south-central Alaska to establish baseline floristic information and identify species of conservation concern. Between 1998 and 2005, we collected 815 taxa, the majority of which were new records for one or more park units. We present descriptions of the...

doi: 10.1890/11-2136.1

We examined the phenology, or the timing of biological events, in aspen trees in interior Alaska. Specifically, we observed the dates of leaf out, flowering and fall senescence in aspen in plots in parks within the Central Alaska Network. We first examined six years of aspen phenology observations taken from two very different areas (one a steep, d...

The timing of biological events in the far north are often strictly controlled by physical factors associated with climate because of extreme temperature changes during the year. This means that our changing climate will have far-reaching and profound effects on species living in the north. The timing of recurring biological events, or phenology, a...

Erioderma pedicellatum (Hue) P.M. Jørg is a globally rare, foliose cyanolichen known from Scandinavia and southeastern Canada. In August 2007, several thalli of E. pedicellatum were collected in Denali National Park and Preserve on the south side of the Alaska Range, Alaska, USA. Subsequently, several additional thalli were observed in nearby Denal...

An inventory of the vascular plant flora of Wrangell-St. Elias National Park and Preserve, Alaska, was conducted from 1994 to 1997 and in 2003. This 13.2 million acre National Park comprises 16% of all National Park Service lands. The objectives of the inventory were to assess the genetic diversity of the region, identify rare taxa and areas of phy...

During the summer of 2002, we conducted a vascular plant inventory of Yukon-Charley Rivers National Preserve, Alaska, as part of the Biological Inventories for the Natural Resource Challenge. The principal goals of the survey were to produce a voucher-based list of vascular plant species that documents 90% of the species expected to exist within th...

ABSTRACT Carl A. Roland 2004. The Vascular Plant Floristics of Denali National Park and Preserve: A Summary, Including the Results of Inventory Fieldwork 1998 - 2001. Denali National Park and Preserve, P.O. Box 9, Denali Park, Alaska, 99755. A reconnaissance inventory of the vascular plant flora of Denali National Park and Preserve was conducted du...

Accession Number: 9462141; Cook, Mary B.; Roland, Carl A.; Issue Info: Apr-Jun2002, Vol. 116 Issue 2, p192; Thesaurus Term: NATIONAL parks & reserves; Thesaurus Term: PHYTOGEOGRAPHY; Subject Term: INVENTORIES; Subject: ALASKA; Subject: UNITED States; NAICS/Industry Codes: 712190 Nature Parks and Other Similar Institutions; Number of Pages: 113p; Il...

Accession Number: 8414268; Roland, Carl A.; Cook, M.B. Issue Info: Jan/Mar1998, Vol. 112 Issue 1, p158; Subject: ALASKA; Subject: UNITED States; Author-Supplied Keyword: Alaska; Author-Supplied Keyword: Cryptantha shackletteana; Author-Supplied Keyword: Endemic species; Author-Supplied Keyword: Range extension; Author-Supplied Keyword: Rare plant;...