Recherche

MacColl, Kevin; Tosi, Micaela; Chagnon, Pierre-Luc; MacDougall, Andrew; Dunfield, Kari; Maherali, Hafiz — 2024-03-20 We conducted a study on the effect of ecological restoration of former agricultural fields on the abundance and community composition of arbuscular mycorrhizal fungi. These files contain data for each sample plot including soil characteristics, AM fungal abundance, species richness, phylogenetic dispersion, and community composition. Each data file has a corresponding metadata file that describes how the raw data has been organized.

Hodapp, Dorothee; Borer, Elizabeth T.; Harpole, W. Stanley; Lind, Eric M.; Seabloom, Eric W.; Adler, Peter B.; Alberti, Juan; Arnillas, Carlos A.; Bakker, Jonathan D.; Biederman, Lori; Cadotte, Marc; Cleland, Elsa E.; Collins, Scott; Fay, Philip A.; Firn, Jennifer; Hagenah, Nicole; Hautier, Yann; Iribarne, Oscar; Knops, Johannes M.H.; McCulley, Rebecca L.; MacDougall, Andrew; Moore, Joslin L.; Morgan, John W.; Mortensen, Brent; La Pierre, Kimberly J.; Risch, Anita C.; Schuetz, Martin; Peri, Pablo; Stevens, Carly J.; Wright, Justin; Hillebrand, Helmut; Knops, Johannes M. H. — 2019-05-24 Environmental change can result in substantial shifts in community composition. The associated immigration and extinction events are likely constrained by the spatial distribution of species. Still, studies on environmental change typically quantify biotic responses at single spatial (time series within a single plot) or temporal (spatial beta-diversity at single time points) scales, ignoring their potential interdependence. Here, we use data from a global network of grassland experiments to determine how turnover responses to two major forms of environmental change – fertilization and herbivore loss – are affected by species pool size and spatial compositional heterogeneity. Fertilization led to higher rates of local extinction whereas turnover in herbivore exclusion plots was driven by species replacement. Overall, sites with more spatially heterogeneous composition showed significantly higher rates of annual turnover, independent of species pool size and treatment. Taking into account spatial biodiversity aspects will therefore improve our understanding of consequences of global and anthropogenic change on community dynamics.

MacDougall, Andrew — 2021-05-19 <p>This directory contains the UVic ESCM model output for MacDougall, 2021, “Estimated effect of the permafrost carbon feedback on the zero emissions commitment to climate change”</p> <p>Parameters: Contains ASCII files with parameter values for each model variant. ECS is degrees K per doubling of atmospheric CO2. Arctic amplification is the ratio of warming north of 60 degrees divided by global temperature.</p> <p>1pct_1000: ZECMIP A1 experiment with permafrost carbon</p> <p>1pct_1000_NoPFC: ZECMIP A1 experiment with out permafrost carbon</p> <p>1pct_2000: ZECMIP A3 experiment with permafrost carbon</p> <p>1pct_2000_NoPFC: ZECMIP A3 experiment with out permafrost carbon</p>

MacDougall, Andrew — 2021-06-17 UVic ESCM simulations for: Estimated climate impact of replacing agriculture as the primary food production system Directory "Idealized" contains simulations of individual and combined agricultural climate forcings. "LUC" is land-use-change. "biophys" are simulation of the biophysical component of land-use change. Directory "SSPs" contains simulations with the Shared Socioeconomic Pathways. "ECS" denoted equilibrium climate sensitivity. "Baseline" are the standard SSP simulations. "Emissions" are the CO2 emissions driven simulations with bacilliculture. " Temperature_Track" are simulations which track the temperature in the baseline simulations with bacilliculture (used to estimate additional allowable emissions). "No_Negative_Emission" are modified emission driven simulations with bacilliculture, wherein CO2 emissions are halted at 0 and thus negative emissions are not allowed.

Gilbert, Benjamin; MacDougall, Andrew; Kadoya, Taku; Akasaka, Munemitsu; Bennett, Joseph; Lind, Eric; Flores-Moreno, Habacuc; Firn, Jennifer; Hautier, Yann; Borer, Elizabeth; Seabloom, Eric; Adler, Peter; Cleland, Elsa; Grace, James; Harpole, W.; Esch, Ellen; Moore, Joslin; Knops, Jean; McCulley, Rebecca; Mortensen, B.; Bakker, J.; Fay, Philip — 2020-04-01 <p><b>Aim</b>: Climate variability threatens to destabilize production in many ecosystems. Asynchronous species dynamics may buffer against such variability when decreased performance by some species is offset by increased performance of others. However, high climatic variability can eliminate species through stochastic extinctions or cause similar stress responses among species, reducing buffering. Local conditions, such as soil nutrients, can further alter production stability directly or by influencing asynchrony. We test these hypotheses using a globally distributed sampling experiment.</p> <p><b>Location</b>: Grasslands in North America, Europe and Australia.</p> <p><b>Time period</b>: Annual surveys over five-year intervals occurring between 2007 and 2014.</p> <p><b>Major taxa studied</b>: Herbaceous plants.</p> <p><b>Methods</b>: We annually sampled per-species cover and aboveground community biomass (net primary productivity; NPP), plus soil chemical properties, in twenty-nine grasslands. We tested how soil conditions, combined with precipitation and temperature variability, affect species richness, asynchrony and temporal stability of primary productivity. We used bivariate relationships and structural equation modeling to examine proximate and ultimate relationships.</p> <p><b>Results</b>: Climate variability strongly predicted asynchrony, whereas NPP stability was more related to soil conditions. Species richness was structured by both climate variability and soils, and in turn increased asynchrony. Temperature and precipitation variability caused a unimodal asynchrony response, with asynchrony lowest at low and high climate variability. Climate impacted stability indirectly through its effect on asynchrony, with stability increasing at higher asynchrony due to lower inter-annual NPP variability. Soil conditions had no detectable effect on asynchrony but increased stability by increasing mean NPP, especially when soil organic matter was high.</p> <p><b>Main Conclusions</b>: We found globally consistent evidence that climate modulates species asynchrony, but that the direct effect on stability is low relative to local soil conditions. Nonetheless, our observed unimodal responses to temperature and precipitation variability suggest asynchrony thresholds, beyond which there are detectable destabilizing impacts of climate on primary productivity.</p>