Sean Michaletz results 16
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Rapid Climate Acclimation (Not Traits or Phylogeny) Drives Variation in Photosynthesis Temperature ResponseNARA Subscribed
Understanding variation in plant assimilation‐temperature (AT) responses is essential for improving forecasts of climate change feedbacks and their impacts on the biosphere. Previous studies have focused on acclimation to weather or adaptation to climate of origin, but relationships between AT response parameters and leaf functional traits or phylogeny have received little attention. To evaluate the influence of climate, trait...
Describing Scaling Relationships Scaling relationships are a central feature of global ecology, quantifying general biological patterns across broad spatial and temporal scales. Traditionally characterised as scale‐invariant power laws, the scope of biological scaling has expanded in recent decades to include log–log curvilinearity and exponential functions. In macroecology and biogeography, a major focus is on quantifying the...
Acclimation Unifies the Scaling of Carbon Assimilation Across Climate Gradients and Levels of OrganisationNARA Subscribed
The temperature dependence of carbon assimilation—from leaf photosynthesis to ecosystem productivity—is hypothesised to be driven by the kinetics of Rubisco‐catalysed carboxylation and electron transport. However, photosynthetic physiology acclimates to changes in temperature, which may decouple temperature dependencies at higher levels of organisation from the acute temperature sensitivity of photosynthesis. Here, we integrat...
Fungal composition associated with host tree identity mediates nutrient addition effects on wood microbial respirationNARA Subscribed
Fungi are key decomposers of deadwood, but the impact of anthropogenic changes in nutrients and temperature on fungal community and its consequences for wood microbial respiration are not well understood. Here, we examined how nitrogen and phosphorus additions (field experiment) and warming (laboratory experiment) together influence fungal composition and microbial respiration from decomposing wood of angiosperms and gymnosper...
Hotter is not (always) better: Embracing unimodal scaling of biological rates with temperatureNARA Subscribed
Rate‐temperature scaling relationships have fascinated biologists for nearly two centuries and are increasingly important in our era of global climate change. These relationships are hypothesized to originate from the temperature‐dependent kinetics of rate‐limiting biochemical reactions of metabolism. Several prominent theories have formalized this hypothesis using the Arrhenius model, which characterizes a monotonic temperatu...
Global maps of soil temperatureNARA Subscribed
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1‐km 2 r...
Traits mediate drought effects on wood carbon fluxesNARA Subscribed
CO 2 fluxes from wood decomposition represent an important source of carbon from forest ecosystems to the atmosphere, which are determined by both wood traits and climate influencing the metabolic rates of decomposers. Previous studies have quantified the effects of moisture and temperature on wood decomposition, but these effects were not separated from the potential influence of wood traits. Indeed, it is not well understood...
Stomata regulate CO 2 uptake for photosynthesis and water loss through transpiration. The approaches used to represent stomatal conductance ( g s ) in models vary. In particular, current understanding of drivers of the variation in a key parameter in those models, the slope parameter (i.e. a measure of intrinsic plant water‐use‐efficiency), is still limited, particularly in the tropics. Here we collected diurnal measurements o...
TRY plant trait database – enhanced coverage and open accessNARA Subscribed
Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodivers...
Wood decomposition is a major component of the global carbon cycle. Decomposition rates vary across climate gradients, which is thought to reflect the effects of temperature and moisture on the metabolic kinetics of decomposers. However, decomposition rates also vary with wood traits, which may reflect the influence of stoichiometry on decomposer metabolism as well as geometry relating the surface areas that decomposers coloni...
Summary Temperature is an important correlate of global patterns of biodiversity, yet the mechanisms driving these relationships are not well understood. Taxa‐area relationships (TARs) have been intensively examined, but the effects of temperature on TARs, particularly for microbial communities, are largely undocumented. Here we present a continental‐scale description of temperature‐dependent nested TARs of microbial communiti...
Taxonomic decomposition of the latitudinal gradient in species diversity of North American florasNARA Subscribed
Aim To test the latitudinal gradient in plant species diversity for self‐similarity across taxonomic scales and amongst taxa. Location North America. Methods We used species richness data from 245 local vascular plant floras to quantify the slope and shape of the latitudinal gradients in species diversity ( LGSD ) across all plant species as well as within each family and order. We calculated the contribution of each family an...
Terrestrial net primary production (NPP) varies across global climate gradients, but the mechanisms through which climate drives this variation remain subject to debate. Specifically, it is debatable whether NPP is primarily influenced by ‘direct’ effects of climate on the kinetics of plant metabolism or ‘indirect’ effects of climate on plant size, stand biomass, stand age structure and growing season length. We clarify severa...
Assessing trait‐based scaling theory in tropical forests spanning a broad temperature gradientNARA Subscribed
Aim Tropical elevation gradients are natural laboratories to assess how changing climate can influence tropical forests. However, there is a need for theory and integrated data collection to scale from traits to ecosystems. We assess predictions of a novel trait‐based scaling theory, including whether observed shifts in forest traits across a broad tropical temperature gradient are consistent with local phenotypic optima and a...
Biogeochemistry drives diversity in the prokaryotes, fungi, and invertebrates of a Panama forestNARA Subscribed
Humans are both fertilizing the world and depleting its soils, decreasing the diversity of aquatic ecosystems and terrestrial plants in the process. We know less about how nutrients shape the abundance and diversity of the prokaryotes, fungi, and invertebrates of Earth's soils. Here we explore this question in the soils of a Panama forest subject to a 13‐yr fertilization with factorial combinations of nitrogen (N), phosphorus...
Biogeographic patterns of soil diazotrophic communities across six forests in the North AmericaNARA Subscribed
Soil diazotrophs play important roles in ecosystem functioning by converting atmospheric N 2 into biologically available ammonium. However, the diversity and distribution of soil diazotrophic communities in different forests and whether they follow biogeographic patterns similar to macroorganisms still remain unclear. By sequencing nifH gene amplicons, we surveyed the diversity, structure and biogeographic patterns of soil dia...
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