Many Low Arctic tundra regions are currently undergoing a vegetation shift towards increasing growth and groundcover of tall deciduous shrubs due to recent climate warming. Vegetation change directly affects ecosystem carbon balance, but it can also affect soil biogeochemical cycling through physical and biological feedback mechanisms. Recent studies indicate that […]
Sub-arctic birch forests (Betula pubescens Ehrh. ssp. czerepanovii) periodically suffer large-scale defoliation events caused by the caterpillars of the geometrid moths Epirrita autumnata and Operophtera brumata. Despite their obvious influence on ecosystem primary productivity, little is known about how the associated reduction in belowground C allocation affects soil processes. We […]
Ecological memory stored in a landscape can help an ecosystem recover from disturbances like fire and outbreaks of disease. But what happens when climate warming disrupts that process? How long before ecological memories stored in the warming Arctic are overwritten by new ones, and what does that mean for the […]
More severe and frequent fires in the Alaskan boreal forest are releasing vast stores of carbon and nitrogen from burned trees and soil into the atmosphere, a trend that could accelerate climate warming. But new research published this week in the journal Science shows that the deciduous trees replacing burned […]
Nitrogen (N2)-fixing moss microbial communities play key roles in nitrogen cycling of boreal forests. Forest type and leaf litter inputs regulate moss abundance, but how they control moss microbiomes and N2-fixation remains understudied. We examined the impacts of forest type and broadleaf litter on microbial community composition and N2-fixation rates […]
Dominant canopy tree species have strong effects on the composition and function of understory species, particularly bryophytes. In boreal forests, bryophytes and their associated microbes are a primary source of ecosystem nitrogen (N) inputs, and an important process regulating ecosystem productivity. We investigated how feather moss-associated N2-fixation rates and contribution […]
Increased fire severity in boreal forests of Interior Alaska is shifting forest canopy composition from black spruce (Picea mariana) to deciduous species, including trembling aspen (Populus tremuloides) and Alaska paper birch (Betula neoalaskana). Because deciduous trees are less flammable than black spruce, the dominant disturbance regime in deciduous forests could […]
Global change models predict that high-latitude boreal forests will become increasingly susceptible to fire activity as climate warms, possibly causing a positive feedback to warming through fire-driven emissions of CO2 into the atmosphere. However, fire-climate feedbacks depend on forest regrowth and carbon (C) accumulation over the post-fire successional interval, which […]
The effects of grassland conversion to forest vegetation and of individual tree species on microbial activity in Siberia are largely unstudied. Here, we examined the effects of the six most commonly dominant tree species in Siberian forests (Scots pine, spruce, Arolla pine, larch, aspen and birch) on soil C and […]
Methane consumption by temperate forest soils is a major sink for this important greenhouse gas, but little is known about how tree species influence CH4 uptake by soils. Here, we show that six common tree species in Siberian boreal and temperate forests significantly affect potential CH4 consumption in laboratory microcosms. […]