James Le Moine

James Le Moine
Northern Arizona University | NAU · Center for Ecosystem Science and Society

MS

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36
Publications
4,328
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1,284
Citations

Publications

Publications (36)
Article
Full-text available
Manual chamber-based measurements of CO 2 (and H 2 O) fluxes are important for understanding ecosystem carbon metabolism. Small opaque chambers can be used to measure leaf, stem and soil respiration. Larger transparent chambers can be used to measure net ecosystem exchange of CO 2 , and small jars often serve this purpose for laboratory incubations...
Article
What are the successional trajectories and impacts of disturbances on forest soil nutrient availability? Answers remain elusive because the time scale of interest is long and many factors affect soil properties. We address this question on a regionally representative landscape in northern Michigan, U.S.A. Late-successional reference stands aside, m...
Article
Full-text available
With climate change, forests are expected to receive increased inputs of carbon (C) and nitrogen (N) but it is unclear how this will modify forest C cycling and storage at the molecular-level. To investigate the response of forest soil organic matter (SOM) to changes in soil inputs, a study area was established in a Michigan hardwood forest as part...
Article
Understanding how soil processes, belowground plant and fungal species composition, and nutrient cycles are altered by disturbances is essential for understanding the role forests play in mitigating global climate change. Here we ask: How are root and fungal communities altered in a mid-successional forest during shifts in dominant tree species com...
Article
Although fires are common disturbances in North American forests, the extent to which soil invertebrate assemblages recover from burning remains unclear. Here, we examine long-term (14- to 101-yr) recoveries of soil invertebrate communities from common cut and burn treatments conducted at 6 to 26-yr intervals since 1911 in a deciduous forest in the...
Article
Biomass production in living trees is the basis of numerous forest ecosystem functions and services. However, rates of and controls on biomass production vary widely across temperate forests, particularly over successional timescales of decades and centuries. Biomass production in temperate forests is most often interpreted within the context of bi...
Poster
Surprisingly little is known about how pyrolysis temperature and wood source affect the stability of forest-fire derived pyrogenic organic matter (PyOM). Here, we show that wood source and temperature affect in situ mineralization rates of PyOM in soils for two co- occurring gymnosperm (jack pine; JP [Pinus banksiana]) and angiosperm (red maple; RM...
Article
Full-text available
Exotic earthworm impacts on temperate forest soils are influenced by earthworm community composition and are likely constrained by the degree of organic matter redistribution following earthworm introductions across different soil types; however, the relative importance of these factors remains unknown. We examined how exotic earthworm communities...
Article
Full-text available
Nitrogen (N) transformations in forest soils are fundamentally important to plant and microbial N nutrition and the N balance of forest ecosystems, but changes in the patterns and rates of N transformations during forest succession are poorly understood. In order to better understand how soil N cycling changes during ecosystem succession, we analyz...
Article
Full-text available
The terrestrial biosphere sequesters up to a third of annual anthropogenic carbon dioxide emis-sions, offsetting a substantial portion of greenhouse gas forcing of the climate system. Although a number of factors are responsible for this terrestrial carbon sink, atmospheric nitrogen deposition contributes by enhancing tree productivity and promotin...
Article
Full-text available
Exotic earthworm introductions can alter above- and belowground properties of temperate forests, but the net impacts on forest soil carbon (C) dynamics are poorly understood. We used a mesocosm experiment to examine the impacts of earthworm species belonging to three different ecological groups (Lumbricus terrestris [anecic], Aporrectodea trapezoid...
Poster
Fire is a major controller of forest C cycling by releasing CO 2 to the atmosphere and by contributing pyrogenic organic matter (PyOM or biochar) to soils. Recent studies have shown that much of fire-derived PyOM may turn over in soils at century time scales. Two likely controllers of the chemical structure of PyOM and its resulting decay rate are...
Conference Paper
Background/Question/Methods The dynamics of incipient invasions by exotic earthworm species into northern U.S. temperate forests have been widely documented (frequently characterized as ‘invasion fronts’ moving across landscapes from centralized points of introduction). Understanding factors controlling earthworm species distributions across inva...
Article
Forest succession may cause changes in nitrogen (N) availability, vegetation and fungal community composition that affect N uptake by trees and their mycorrhizal symbionts. Understanding how these changes affect the functioning of the mycorrhizal symbiosis is of interest to ecosystem ecology because of the fundamental roles mycorrhizae play in prov...
Conference Paper
Background/Question/Methods Sandy forest soils in the Great Lakes region store ~80 Mg C ha-1, functioning with vegetation as part of the Northern Hemisphere carbon (C) sink. Our study focuses on the functional diversity of exotic earthworm communities in sandy temperate forest soils and on whether these communities alter the amount and distributi...
Article
Much of our biogeochemical understanding of forest disturbances comes from studies of severe or stand-replacing events, which may have different impacts on coupled carbon (C) and nitrogen (N) cycling than subtler disturbances affecting only a fraction of the canopy. We measured a suite of interdependent C and N cycling processes following an experi...
Article
Belowground carbon (C) and nitrogen (N) cycles are tightly coupled in many northern temperate forests. However, disturbances that cause tree mortality can decouple linkages between belowground components of these biogeochemical cycles. We measured a suite of belowground processes following a treatment to accelerate the natural senescence of early-s...
Conference Paper
Background/Question/Methods In many forests of the upper Great Lakes region, early successional tree species are senescing and giving way to later successional canopy dominants. Will these aging forests continue to sequester carbon (C) at rates comparable to previous decades or will the region decline in its contribution to the North American C si...
Article
Full-text available
The effects of management on soil carbon efflux in different ecosystems are still largely unknown yet crucial to both our understanding and management of global carbon flux. To compare the effects of common forest management practices on soil carbon cycling, we measured soil respiration rate (SRR) in a mixed-conifer and hardwood forest that had und...
Conference Paper
Background/Question/Methods Studies of the stable isotope composition (13C and 15N) of fungal sporocarps have produced various explanations for variation in isotopic signatures of these conspicuous participants in forest C and N cycling. Mechanisms responsible for the 15N enrichment of ectomycorrhizal (ECM) sporocarps are particularly relevant fro...
Conference Paper
Background/Question/Methods We analyzed forest floor, soil, and biomass samples collected from the Harvard Forest Chronic N Addition Study plots in 2008 for 15N, after 20 years of N additions (0 and 50 kg N ha-1 yr-1) and 16 years following 2 years of 15N labeling, in order to track long-term fates of tracer additions and assess N deposition effe...
Article
A critical issue in landscape ecology is to understand the effects of disturbances on landscape processes. While there is increasing interest in examining the ecological consequences associated with changes in landscape structure and composition, little is known about how soil respiration across landscapes might be affected within this context. We...
Article
Full-text available
Changes in climate and land use affect soil respiration rates (SRR) significantly, but studies of these effects across entire landscapes are rare. We simulated responses of landscape mean SRR (LMSRR) to such changes from May to October over a 30 yr period in a managed, predominantly forested landscape in northern Wisconsin, USA, using: (1) 6 satell...
Article
Aboveground biomass (AGB; Mg/ha) is defined in this study as a biomass of growing stock trees greater than 2.5 cm in diameter at breast height (dbh) for stands >5 years and all trees taller than 1.3 m for stands <5 years. Although AGB is an important variable for evaluating ecosystem function and structure across the landscape, such estimates are d...
Article
Full-text available
Increased radiative forcing is an inevitable part of global climate change, yet little is known of its potential effects on the energy fluxes in natural ecosystems. To simulate the conditions of global warming, we exposed peat monoliths (depth, 0.6 m; surface area, 2.1 m2) from a bog and fen in northern Minnesota, USA, to three infrared (IR) loadin...
Article
Full-text available
We propose a working framework for future studies of net carbon exchange (NCE) in disturbed landscapes at broad spatial scales based on the central idea that landscape-level NCE is determined by the land mosaic, including its age structure. Within this framework, we argue that the area-of-edge-influence (AEI), which is prevalent in many disturbed,...
Article
Full-text available
To understand the roles of forest management practices in meeting the goals of forest sustainability and CO2 sequestration, we evaluated the effects of burning and thinning treatments on soil respiration and soil environments in an old-growth, mixed-conifer forest in California’s southern Sierra Nevada. Six experimental treatments with two levels o...
Article
Deciduous forests of the eastern US are broadly approaching an ecological threshold in which early successional dominant trees are senescing and giving way to later successional species, with unknown consequences for regional carbon (C) cycling. Though recent research demonstrates that forests may accumulate C for centuries, the mechanisms behind s...
Article
Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Biology." Thesis (M.S.)--University of Toledo, 2004. Bibliography: leaves 42-53.

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