A5037863386- Fire effects on ecosystems
- Climate change and permafrost
- Rangeland and Wildlife Management
- Geology and Paleoclimatology Research
- Ecology and Vegetation Dynamics Studies
- Cryospheric studies and observations
- Peatlands and Wetlands Ecology
- Tree-ring climate responses
- Forest Ecology and Biodiversity Studies
- Indigenous Studies and Ecology
- Lichen and fungal ecology
- Plant Water Relations and Carbon Dynamics
- Forest ecology and management
- Mycorrhizal Fungi and Plant Interactions
- Plant Pathogens and Fungal Diseases
- Coastal wetland ecosystem dynamics
- Botany, Ecology, and Taxonomy Studies
- Species Distribution and Climate Change
- Arctic and Antarctic ice dynamics
- Landslides and related hazards
- Botany and Plant Ecology Studies
- Bioenergy crop production and management
- Ecosystem dynamics and resilience
- Geological Studies and Exploration
- Plant and Fungal Interactions Research
Rocky Mountain Research Station
2023-2025
US Forest Service
2012-2025
University of Alaska Fairbanks
2012-2024
Rocky Mountain Research (United States)
2023-2024
Pacific Northwest Research Station
2013-2024
Cooperative Research Units
2013-2018
John Wiley & Sons (United States)
2016
Ecological Society of America
2016
Harvard University
2016
United States Department of Agriculture
2011
Abstract Predicting plant community responses to changing environmental conditions is a key element of forecasting and mitigating the effects global change. Disturbance can play an important role in these dynamics, by initiating cycles secondary succession generating opportunities for communities long‐lived organisms reorganize alternative configurations. This study used landscape‐scale variations conditions, stand structure, disturbance from extreme fire year Alaska examine how factors...
Fungi play key roles in ecosystems as mutualists, pathogens, and decomposers. Current estimates of global species richness are highly uncertain, the importance stochastic vs. deterministic forces assembly fungal communities is unknown. Molecular studies have so far failed to reach saturated, comprehensive diversity. To obtain a more accurate estimate diversity, we used direct molecular approach census diversity boreal ecosystem with precisely known plant carefully evaluated adequacy sampling...
In the boreal forests of interior Alaska, feedbacks that link forest soils, fire characteristics, and plant traits have supported stable cycles succession for past 6000 years. This high resilience stands to disturbance is by two interrelated feedback cycles: (i) interactions among regime plant–soil–microbial regulate soil organic layer thickness cycling energy materials, (ii) conditions, regeneration traits, effects on environment maintain community composition. Unusual events can disrupt...
As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release offset by increased production Arctic boreal biomass; however, lack robust estimates net balance increases risk further overshooting international emissions targets. Precise empirical or model-based assessments critical factors driving are unlikely in near future, so address gap, we present from 98...
Shifts in moss communities may affect the resilience of boreal ecosystems to a changing climate because role species regulating soil and biogeochemical cycling. Here, we use long-term data analysis literature synthesis examine ecosystem succession, productivity, decomposition. In Alaskan forests, abundance showed unimodal distribution with time since fire, peaking 30–70 years post-fire. We found no evidence mosses compensating for low vascular productivity low-fertility sites at large...
This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth dominant tree species, plant disease and insect outbreaks, thawing permafrost, drying lakes, increased wildfire extent, postfire recruitment deciduous trees, safety hunters traveling on river ice. These changes have modified key structural features, feedbacks, interactions in forest, including effects upland permafrost regional hydrology, expansion...
Boreal forests play critical roles in global carbon, water and energy cycles. Recent studies suggest drought is causing a decline boreal spruce growth, leading to predictions of widespread mortality shift dominant vegetation type interior Alaska. We took advantage large set tree cores collected from random locations across vast area Alaska examine long-term trends carbon isotope discrimination growth black white spruce. Our results confirm that both species sensitive moisture availability,...
The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations species composition climate feedbacks (e.g., carbon, radiation budgets) that important regional societal consequences human forest ecosystems. In this paper we present the first comprehensive synthesis climate-change impacts on all forested ecosystems Alaska, highlighting changes most critical biophysical factors each region. We developed conceptual framework...
Disturbance can both initiate and shape patterns of secondary succession by affecting processes community assembly. Thus, understanding assembly rules is a key element predicting ecological responses to changing disturbance regimes. We measured the composition trait characteristics plant communities early after widespread wildfires in Alaska assess how variations influenced relative success different regeneration strategies. compared post-fire abundance traits across range fire severities...
Abstract Disturbances can interrupt feedbacks that maintain stable plant community structure and create windows of opportunity for vegetation to shift alternative states. Boreal forests are dominated by tree species overlap considerably in environmental niche, but there few tests what conditions initiate sustain different forest Here, we examine patterns post‐fire growth density seedlings early succession use structural equation models estimate relative effects pre‐fire conditions, fire...
Scenario studies have emerged as a powerful approach for synthesizing diverse forms of research and articulating evaluating alternative socioecological futures. Unlike predictive modeling, scenarios do not attempt to forecast the precise or probable state any variable at given point in future. Instead, comparisons among set contrasting are used understand systemic relationships dynamics complex systems define range possibilities uncertainties quantitative qualitative terms. We describe five...
Along the Tanana River floodplain, several turning points have been suggested to characterize changes in ecosystem structure and function that accompany plant community through primary succession. In past, much of this research focused on a presumed chronosequence uses space for time substitutions. Within chronosequence, permanent vegetation plots repeatedly measured over provide an excellent test model. We analyzed both canopy understory data collected since 1987 Bonanza Creek Experimental...
Long-term experiments provide a way to test presumed causes of successional or environmentally driven vegetation changes. Early-successional nitrogen (N)-fixing plants are widely thought facilitate productivity and development on N-poor sites, thus accounting for observed patterns later in succession. We tested this facilitative impact 23-yr field experiment an Interior Alaska (USA) floodplain. On three replicate early-successional silt bars, we planted late-successional white spruce (Picea...
Boreal forests are critical sinks in the global carbon cycle. However, recent studies have revealed increasing frequency and extent of wildfires, decreasing landscape greenness, tree mortality declining growth black white spruce boreal North America. We measured ring widths from a large set increment cores collected across vast area interior Alaska examined implications data processing decisions for apparent trends growth. found that choice detrending method had important long-term strength...
The boreal forest is the second largest terrestrial biome, and black spruce (Picea mariana (Mill.) BSP) type occupies a large extent of North America. Black communities occur in variety environmental conditions are especially important context climate change because underlain permafrost much northern forests, as well their adaptation to fire disturbance. We used classification ordination approach describe name Alaskan relate them key variables. analyzed relationship species richness with...
Question: How do pre-fire conditions (community composition and environmental characteristics) climate-driven disturbance characteristics (fire severity) affect post-fire community in black spruce stands? Location: Northern boreal forest, interior Alaska. Methods: We compared plant stand 14 stands before after multiple, naturally occurring wildfires. used a combination of vegetation table sorting, univariate (ANOVA, paired t-tests), multivariate (detrended correspondence analysis) statistics...
Northern peatlands represent a long-term net sink for atmospheric CO 2 , but these ecosystems can shift from carbon (C) sinks to sources based on changing climate and environmental conditions. In particular, changes in water availability associated with control peatland vegetation uptake processes. We examined the influence of hydrology plant species abundance ecosystem primary production an Alaskan fen by manipulating table field treatments mimic either sustained flooding (raised table) or...
Abstract The boreal biome represents approximately one third of the world's forested area and plays an important role in global biogeochemical energy cycles. Numerous studies Alaska have concluded that growth black white spruce is declining as a result temperature‐induced drought stress. combined evidence changes fire regime favor establishment deciduous tree species has led some investigators to suggest region may be transitioning from dominance by forests and/or grasslands. Although trends...
Abstract Subsistence harvesters in high latitudes rely on frozen rivers for winter access to local resources. During recent decades, interior Alaskan residents have observed changes river ice regimes that are significant hindrances travel and subsistence practices. We used remote sensing combination with observations examine seasonality of breakup freeze-up assess the implications harvesters. Spring autumn air temperatures, respectively, were found impact timing (−2.0 days °C−1) (+2.0 °C−1)....
Cold, H. S., T. J. Brinkman, C. L. Brown, N. Hollingsworth, D. R. and K. M. Heeringa. 2020. Assessing vulnerability of subsistence travel to effects environmental change in Interior Alaska. Ecology Society 25(1):20. https://doi.org/10.5751/ES-11426-250120
Abstract Climate change is expected to induce shifts in the composition, structure and functioning of Arctic tundra ecosystems. Increases frequency severity fires have potential catalyse vegetation transitions with far‐reaching local, regional global consequences. We propose that post‐fire recovery, coupled climate change, may not necessarily lead pre‐fire conditions. Our hypothesis, based on surveys literature, suggests two climate–fire driven trajectories. One trajectory results increased...