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- Aim We evaluated whether the performance of individuals and populations of the invasive plant Verbascum thapsus differs between its native and non-native ranges, across climate gradients, and in response to its position in a global- scaled niche model. Location India (Kashmir) and Switzerland (native range) and Australia and USA (Hawaii, Montana and Oregon) (non-native range). Methods We measured population characteristics (density of flowering indi- viduals, population size), plant traits (plant height, number of flowering branches) and seed germination for 50 populations of V. thapsus...AuthorsTim Seipel, Jake M. Alexander, Curtis C. Daehler, Lisa J. Rew, Peter J. Edwards, Pervaiz A. Dar, Keith McDougall, Bridgett Naylor, Catherine Parks, Fredric W. Pollnac, Zafar A. Reshi, Mel Schroder, Christoph Kueffer, Peter PearmanKeywordsSourceJournal of BiogeographyYear2014
- The transport of solutes along hyporheic flowpaths is recognized as central to numerous biogeochemical cycles, yet our understanding of how this transport changes with baseflow recession, particularly in a spatially distributed manner, is limited. We conducted four steady-state solute tracer injections and collected electrical resistivity data to characterize hyporheic transport during seasonal baseflow recession in the H.J. Andrews Experimental Forest (Oregon, USA). We used temporal moment analysis of pixels generated from inversion of electrical resistivity data to compress time-lapse...AuthorsAdam S. Ward, Michael N. Gooseff, Michael Fitzgerald, Thomas J. Voltz, Kamini SinghaKeywordsSourceJournal of Hydrology. 517: 362-377.Year2014
- The rate at which trees regenerate following stand-replacing wildfire is an important but poorly understood process in the multi-century development of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) forests. Temporal patterns of Douglas-fir establishment reconstructed from old-growth forests (>450 year) have generated contradictory models of either rapid (100 year) periods of establishment, while patterns of tree establishment in mid-aged (100 to 350 year) forests remains largely unknown. To determine temporal patterns of Douglas-fir...AuthorsJames A. Freund, Jerry F. Franklin, Andrew J. Larson, James A. LutzKeywordsSourceCanadian Journal of Forest Research. 44(9): 1068-1078.Year2014
- Stream functioning includes simultaneous interaction among solute transport, nutrient processing, and metabolism. Metabolism is measured with methods that have limited spatial representativeness and are highly uncertain. These problems restrict development of methods for up-scaling biological processes that mediate nutrient processing. We used the resazurin–resorufin (Raz-Rru) tracer system to estimate metabolism at different spatial scales (habitat, subreach, and reach) in 2 headwater streams of the H. J. Andrews Experimental Forest (Oregon, USA), and present a mathematical framework for...AuthorsRicardo González-Pinzón, Roy Haggerty, Alba ArgerichKeywordsSourceFreshwater Science. 33(3): 798-811.Year2014
- Many modern environmental problems span vastly different spatial scales, from the management of local ecosystems to understanding globally interconnected processes, and addressing them through international policy. MIREN tackles one such “glocal” (global/local) environmental problem – plant invasions in mountains – through a transdisciplinary, multi-scale learning process at the science-policy interface. The approach led to a new framing of invasions in mountains, and promoted innovation by engaging scientists and practitioners.AuthorsChristoph Kueffer, Curtis Daehler, Hansjörg Dietz, Keith McDougall, Catherine Parks, Aníbal Pauchard, Lisa RewSourceGAIA - Ecological Perspectives for Science and SocietyYear2014
- Because iso- and anisohydric species differ in stomatal regulation of the rate and magnitude of fluctuations in shoot water potential, they may be expected to show differences in the plasticity of their shoot water relations components, but explicit comparisons of this nature have rarely been made. We subjected excised shoots of co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis to pressure-volume analysis with and without prior artificial rehydration. In J. monosperma, the shoot water potential at turgor loss (¥×TLP) ranged from −3.4 MPa in artificially rehydrated...AuthorsFrederick Meinzer, David R. Woodruff, Danielle Marias, Katherine McCulloh, Sanna SevantoKeywordsSourcePlant, Cell & Environment. 37(11): 2577-2586.Year2014
- Published data for temperate forests across the world are analyzed to investigate the potential for generalized quantitative expressions of catchment sediment yield impact in the years immediately following logging. Such generalizations would be useful in a variety of forestry and engineering tasks and would aid the spread of knowledge amongst both relevant professionals and new students. Data were assembled for paired catchment studies (51 catchments including 16 controls) that enabled the postlogging sediment yield impact to be compared with both the prelogging period and an undisturbed...AuthorsJames C. Bathurst, Andrés IrouméSourceWater Resources Research. 50(11): 8383-8402.Year2014
- Worldwide, lack of data on stream temperature has motivated the use of regression-based statistical models to predict stream temperatures based on more widely available data on air temperatures. Such models have been widely applied to project responses of stream temperatures under climate change, but the performance of these models has not been fully evaluated. To address this knowledge gap, we examined the performance of two widely used linear and nonlinear regression models that predict stream temperatures based on air temperatures. We evaluated model performance and temporal stability...AuthorsIvan Arismendi, Mohammad Safeeq, Jason B Dunham, Sherri JohnsonKeywordsSourceEnvironmental Research LettersYear2014
- Very large-fires (VLFs) have widespread impacts on ecosystems, air quality, fire suppression resources, and in many regions account for a majority of total area burned. Empirical generalized linear models of the largest fires (>5000 ha) across the contiguous United States (US) were developed at ¡60 km spatial and weekly temporal resolutions using solely atmospheric predictors. Climate−fire relationships on interannual timescales were evident, with wetter conditions than normal in the previous growing season enhancing VLFs probability in rangeland systems and with concurrent long-term...AuthorsR Barbero, J T Abatzoglou, E A SteelKeywordsSourceEnvironmental Research Letters. 9(12): 124009.Year2014
- Seasonal changes in the climatic potential for very large wildfires (VLWF >= 50,000 ac~20,234 ha) across the western contiguous United States are projected over the 21st century using generalized linear models and downscaled climate projections for two representative concentration pathways (RCPs). Significant (pAuthorsDonald McKenzie, John T. Abatzoglou, E. Natasha Stavros, Narasimhan K. LarkinKeywordsSourceClimatic Change. 126(3-4): 455-468. 14 p.Year2014