Mark J. Lara
A5036063743- Climate change and permafrost
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Peatlands and Wetlands Ecology
- Arctic and Antarctic ice dynamics
- Geological Studies and Exploration
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Fire effects on ecosystems
- Landslides and related hazards
- Indigenous Studies and Ecology
- Soil and Unsaturated Flow
- Hydrocarbon exploration and reservoir analysis
- Aeolian processes and effects
- Remote Sensing in Agriculture
- Groundwater and Isotope Geochemistry
- Soil Carbon and Nitrogen Dynamics
- Animal Ecology and Behavior Studies
- Smart Materials for Construction
- Remote Sensing and LiDAR Applications
- Species Distribution and Climate Change
- Ecology and Vegetation Dynamics Studies
- Polar Research and Ecology
- Lichen and fungal ecology
- Remote Sensing and Land Use
University of Illinois Urbana-Champaign
2017-2025
University of Alaska Fairbanks
2014-2020
University of Illinois System
2019-2020
The University of Texas at El Paso
2011-2019
Abstract Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are major source the large spread across in terrestrial C sink from third to fifth assessment reports Intergovernmental Panel on Climate Change (IPCC). Improving soil projections high priority for modeling future IPCC other assessments. To achieve this goal, we suggest that (1) model structures should reflect real‐world processes, (2) parameters be calibrated match outputs with...
Arctic tundra ecosystems have experienced unprecedented change associated with climate warming over recent decades. Across the Pan-Arctic, vegetation productivity and surface greenness trended positively period of satellite observation. However, since 2011 these trends slowed considerably, showing signs browning in many regions. It is unclear what factors are driving this which regions/landforms will be most sensitive to future browning. Here we provide evidence linking decadal patterns...
Abstract The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries millennia, and now dominated by ice‐wedge polygonal tundra that spans drained thaw‐lake basins interstitial tundra. In nearby regions, studies identified a rapid increase thermokarst formation (i.e., pits) recent decades response climate warming, facilitating changes geomorphology. We assessed future impact 100 years geomorphic change on peak growing season carbon exchange to: (i)...
Abstract. Methane emissions from boreal and arctic wetlands, lakes, rivers are expected to increase in response warming associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane circumpolar scales has contributed a large uncertainty our understanding present-day future emissions. Here we present Boreal–Arctic Wetland Lake Dataset (BAWLD), dataset based on an expert assessment, extrapolated using random forest modelling available...
Abstract Plant‐mediated CH 4 flux is an important pathway for land–atmosphere emissions, but the magnitude, timing, and environmental controls, spanning scales of space time, remain poorly understood in arctic tundra wetlands, particularly under long‐term effects climate change. fluxes were measured situ during peak growing season dominant aquatic emergent plants Alaskan coastal plain, Carex aquatilis Arctophila fulva , to assess magnitude species‐specific controls on flux. Plant biomass was...
Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands Tanana Flats central for centuries, as thawing collapses that transition to wetlands. Located within discontinuous zone, this region significantly warmed over past half-century, much these carbon-rich soils now ~0.5 °C thawing. Increased thaw lowland...
Abstract. Ponds and lakes are abundant in Arctic permafrost lowlands. They play an important role wetland ecosystems by regulating carbon, water, energy fluxes providing freshwater habitats. However, ponds, i.e., waterbodies with surface areas smaller than 1. 0 × 104 m2, have not been inventoried on global regional scales. The Permafrost Region Pond Lake (PeRL) database presents the results of a circum-Arctic effort to map ponds from modern (2002–2013) high-resolution aerial satellite...
Abstract The expansion of shrubs across the Arctic tundra may fundamentally modify land–atmosphere interactions. However, it remains unclear how shrub pattern is linked with key environmental drivers, such as climate change and fire disturbance. Here we used 40+ years high‐resolution (~1.0 m) aerial satellite imagery to estimate shrub‐cover in 114 study sites four burned unburned upland (ice‐poor) lowland (ice‐rich) ecosystems northern Alaska. Validated data from additional fires, our...
Increases in the availability of nitrogen (N) may have consequences for plant growth and nutrient cycling N-limited tundra communities. We investigated impact alder (Alnus viridis spp. fruticosa), an N-fixing deciduous shrub, has on N at a hillslope located Alaska's Seward Peninsula. quantified fixation using 15N2 incubations within two distinct communities this site: shrublands well-drained, rocky outcroppings uplands savannas water tracks along moist toeslope hill. Annual rates were 1.95 ±...
Abstract In northern Alaska nearly 65% of the terrestrial surface is composed polygonal ground, where geomorphic tundra landforms disproportionately influence carbon and nutrient cycling over fine spatial scales. Process-based biogeochemical models used for local to Pan-Arctic projections ecological responses climate change typically operate at coarse-scales (1km 2 –0.5°) which fine-scale (<1km ) heterogeneity often aggregated dominant land cover unit. Here, we evaluate importance...
ABSTRACT Deep‐learning (DL) models have become increasingly beneficial for the detection of retrogressive thaw slumps (RTS) in permafrost domain. However, comparing accuracy metrics is challenging due to unstandardized labeling guidelines. To address this, we conducted an experiment with 12 international domain experts from a broad range scientific backgrounds. Using 3 m PlanetScope multispectral imagery, they digitized RTS footprints two sites. We evaluated label uncertainty by manually...
Knowledge of how arctic plant communities will respond to change has been largely derived from plot level experimental manipulation, not trends decade time scale environmental observations. This study documents community in 330 marked plots at 33 sites established during the International Biological Program near Barrow, Alaska 1972. Plots were resampled 1999, 2008 and 2010 for species cover presence. Cluster analysis identified nine Non-metric multidimensional scaling (NMS) indicates that...
Arctic lakes located in permafrost regions are susceptible to catastrophic drainage. In this study, we reconstructed historical lake drainage events on the western Coastal Plain of Alaska between 1955 and 2017 using USGS topographic maps, aerial photography (1955), Landsat Imagery (ca. 1975, ca. 2000, annually since 2000). We identified 98 larger than 10 ha that partially (>25% area) or completely drained during 62-year period. Decadal-scale rates progressively declined from 2.0 lakes/yr...
To determine the role lemmings play in structuring plant communities and their contribution to 'greening of Arctic', we measured cover biomass 50 + year old lemming exclosures control plots coastal tundra near Barrow, Alaska. The response functional types herbivore exclusion varied among land types. In general, abundance lichens bryophytes increased with lemmings, whereas graminoids decreased, although magnitude these responses These results suggest that sustained activity promotes a higher...
Abstract Arctic tundra landscapes are composed of a complex mosaic patterned ground features, varying in soil moisture, vegetation composition, and surface hydrology over small spatial scales (10–100 m). The importance microtopography associated geomorphic landforms influencing ecosystem structure function is well founded, however, data products describing local to regional scale distribution or polygonal geomorphology largely unavailable. Thus, our understanding impacts on processes (e.g.,...
Summary To date, the majority of our knowledge regarding impacts herbivory on arctic ecosystem function has been restricted to short‐term (<5 years) exclusion or manipulation experiments. Our understanding long‐term responses sustained and/or herbivore tundra is severely limited. Recent evidence suggests lemming population outbreaks, which have historically common in regions, become less frequent and some cases disappeared. Here, we evaluate how 50+ years absence impacted carbon energy...