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Full-Text Articles in Physical Sciences and Mathematics
Null Model Analysis Of Species Associations Using Abundance Data, Werner Ulrich, Nicholas J. Gotelli
Null Model Analysis Of Species Associations Using Abundance Data, Werner Ulrich, Nicholas J. Gotelli
College of Arts and Sciences Faculty Publications
The influence of negative species interactions has dominated much of the literature on community assembly rules. Patterns of negative covariation among species are typically documented through null model analyses of binary presence/absence matrices in which rows designate species, columns designate sites, and the matrix entries indicate the presence (1) or absence (0) of a particular species in a particular site. However, the outcome of species interactions ultimately depends on population-level processes. Therefore, patterns of species segregation and aggregation might be more clearly expressed in abundance matrices, in which the matrix entries indicate the abundance or density of a species in …
Calibrating A Long-Term Meteoric 10Be Accumulation Rate In Soil, Lucas Reusser, Joseph Graly, Paul Bierman, Dylan Rood
Calibrating A Long-Term Meteoric 10Be Accumulation Rate In Soil, Lucas Reusser, Joseph Graly, Paul Bierman, Dylan Rood
College of Arts and Sciences Faculty Publications
Using 13 samples collected from a 4.1 meter profile in a well-dated and stable New Zealand fluvial terrace, we present the first long-term accumulation rate for meteoric 10Be in soil (1.68 to 1.72 × 106 at/(cm2yr)) integrated over the past ∼18 ka. Site-specific accumulation data, such as these, are prerequisite to the application of meteoric 10Be in surface process studies. Our data begin the process of calibrating long-term meteoric 10Be delivery rates across latitude and precipitation gradients. Our integrated rate is lower than contemporary meteoric 10Be fluxes measured in New Zealand rainfall, suggesting that long-term average precipitation, dust flux, or …
Temporal And Spatial Monitoring Of Mobile Nanoparticles In A Vineyard Soil: Evidence Of Nanoaggregate Formation, N. Perdrial, J. N. Perdrial, J. E. Delphin, F. Elsass, N. Liewig
Temporal And Spatial Monitoring Of Mobile Nanoparticles In A Vineyard Soil: Evidence Of Nanoaggregate Formation, N. Perdrial, J. N. Perdrial, J. E. Delphin, F. Elsass, N. Liewig
College of Arts and Sciences Faculty Publications
Mechanisms of formation, stabilization, liberation, transport and deposition of nanoparticles and their relationship to contaminant transport remain scarcely investigated in natural porous media. This study investigated nanoparticles mobilized in the pore space of a French vineyard soil by observing mobile soil-derived organic matter (SOM) and minerals in pore fluids over an 8-month monitoring period. Samples were collected in situ and investigated by transmission electron microscopy coupled to electron-dispersive spectroscopy. The main types of nanoparticles transported within the soil were clay, bacteria, SOM and nanoaggregates. Nanometric clay particles were enriched in various metals (Fe, Zn, As and Pb) and organically-derived constituents. …
Species Interactions And Thermal Constraints On Ant Community Structure, Sarah E. Wittman, Nathan J. Sanders, Aaron M. Ellison, Erik S. Jules, Jaime S. Ratchford, Nicholas J. Gotelli
Species Interactions And Thermal Constraints On Ant Community Structure, Sarah E. Wittman, Nathan J. Sanders, Aaron M. Ellison, Erik S. Jules, Jaime S. Ratchford, Nicholas J. Gotelli
College of Arts and Sciences Faculty Publications
Patterns of species occurrence and abundance are influenced by abiotic factors and biotic interactions, but these factors are difficult to disentangle without experimental manipulations. In this study, we used observational and experimental approaches to investigate the role of temperature and interspecific competition in controlling the structure of groundforaging ant communities in forests of the Siskiyou Mountains of southwestern Oregon. To assess the potential role of competition, we first used null model analyses to ask whether species partition temporal and/or spatial environments. To understand how thermal tolerances influence the structure of communities, we conducted a laboratory experiment to estimate the maximum …