Time filter

Source Type

Boulder City, CO, United States

Newman G.,Colorado State University | Wiggins A.,University of New Mexico | Crall A.,Colorado State University | Graham E.,University of California at Los Angeles | And 2 more authors.
Frontiers in Ecology and the Environment | Year: 2012

Citizen science creates a nexus between science and education that, when coupled with emerging technologies, expands the frontiers of ecological research and public engagement. Using representative technologies and other examples, we examine the future of citizen science in terms of its research processes, program and participant cultures, and scientific communities. Future citizen-science projects will likely be influenced by sociocultural issues related to new technologies and will continue to face practical programmatic challenges. We foresee networked, open science and the use of online computer/video gaming as important tools to engage non-traditional audiences, and offer recommendations to help prepare project managers for impending challenges. A more formalized citizen-science enterprise, complete with networked organizations, associations, journals, and cyberinfrastructure, will advance scientific research, including ecology, and further public education. © The Ecological Society of America.

Anderson N.,University of Arizona | Czapla-Myers J.,University of Arizona | Leisso N.,National Ecological Observatory Network | Biggar S.,University of Arizona | And 3 more authors.
Applied Optics | Year: 2013

Three improved ground-viewing radiometers were built to support the Radiometric Calibration Test Site (RadCaTS) developed by the Remote Sensing Group (RSG) at the University of Arizona. Improved over previous light-emitting diode based versions, these filter-based radiometers employ seven silicon detectors and one InGaAs detector covering a wavelength range of 400-1550 nm. They are temperature controlled and designed for greater stability and lower noise. The radiometer systems show signal-to-noise ratios of greater than 1000 for all eight channels at typical field calibration signal levels. Predeployment laboratory radiance calibrations using a 1 m spherical integrating source compare well with in situ field calibrations using the solar radiation based calibration method; all bands are within ±2.7% for the case tested. © 2013 Optical Society of America.

Sierra C.A.,Oregon State University | Sierra C.A.,Max Planck Institute for Biogeochemistry | Harmon M.E.,Oregon State University | Thomann E.,Oregon State University | And 2 more authors.
Biogeosciences | Year: 2011

Accelerated release of carbon from soils is one of the most important feedbacks related to anthropogenically induced climate change. Studies addressing the mechanisms for soil carbon release through organic matter decomposition have focused on the effect of changes in the average temperature, with little attention to changes in temperature variability. Anthropogenic activities are likely to modify both the average state and the variability of the climatic system; therefore, the effects of future warming on decomposition should not only focus on trends in the average temperature, but also variability expressed as a change of the probability distribution of temperature. Using analytical and numerical analyses we tested common relationships between temperature and respiration and found that the variability of temperature plays an important role determining respiration rates of soil organic matter. Changes in temperature variability, without changes in the average temperature, can affect the amount of carbon released through respiration over the long-term. Furthermore, simultaneous changes in the average and variance of temperature can either amplify or dampen the release of carbon through soil respiration as climate regimes change. These effects depend on the degree of convexity of the relationship between temperature and respiration and the magnitude of the change in temperature variance. A potential consequence of this effect of variability would be higher respiration in regions where both the mean and variance of temperature are expected to increase, such as in some low latitude regions; and lower amounts of respiration where the average temperature is expected to increase and the variance to decrease, such as in northern high latitudes. © 2011 Author(s).

Wallenstein M.D.,Colorado State University | Haddix M.L.,Colorado State University | Ayres E.,National Ecological Observatory Network | Ayres E.,University of Colorado at Boulder | And 3 more authors.
Soil Biology and Biochemistry | Year: 2013

Recent evidence suggests that soil organic matter (SOM) is largely composed of microbial products rather than plant compounds that resist decomposition. The chemical transformation of leaf litter components during decomposition is critical in controlling SOM formation. Plant leaf litter tends to decompose faster in its native environment than when it is placed under other vegetation types. This home-field advantage (HFA) suggests that decomposer communities are specialized to most efficiently degrade the litter found in their native environment, possibly through the production of specific enzymes that degrade unique compounds within that litter. Could this affect the degree to which leaf litter chemistry is altered during decomposition? We used pyrolysis-molecular beam mass spectrometry (py-MBMS) to analyze whether the chemistry of aspen and lodgepole pine litter was altered to a greater degree when decomposed in its home environment compared to an away environment. We had previously reported a 4% HFA for pine litter decomposition rates in this reciprocal experiment, and attributed that effect to differences in decomposer communities. Our high-resolution analysis revealed that litter chemistry also changed to a greater extent in its home environment. The changes in litter chemistry were more pronounced for the more recalcitrant pine litter, suggesting that decomposer community specialization is more important for recalcitrant litter. The accumulation of microbial products and microbially-transformed plant components resulted in an overall convergence in litter chemistry as decomposition proceeded, but the imprints of both initial litter chemistry and decomposer communities remained evident. The detection of new compounds in decomposed litter and the HFA effect on litter chemistry suggest that decomposer communities affect both the rate at which individual compounds within litter are decomposed, and the chemical nature of compounds that are incorporated into SOM. © 2012 Elsevier Ltd.

Elmendorf S.C.,National Ecological Observatory Network | Elmendorf S.C.,University of Colorado at Boulder | Henry G.H.R.,University of British Columbia | Hollister R.D.,Grand Valley State University | And 15 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Inference about future climate change impacts typically relies on one of three approaches: manipulative experiments, historical comparisons (broadly defined to include monitoring the response to ambient climate fluctuations using repeat sampling of plots, dendroecology, and paleoecology techniques), and space-for-time substitutions derived from sampling along environmental gradients. Potential limitations of all three approaches are recognized. Here we address the congruence among these three main approaches by comparing the degree to which tundra plant community composition changes (i) in response to in situ experimental warming, (ii) with interannual variability in summer temperature within sites, and (iii) over spatial gradients in summer temperature. We analyzed changes in plant community composition from repeat sampling (85 plant communities in 28 regions) and experimental warming studies (28 experiments in 14 regions) throughout arctic and alpine North America and Europe. Increases in the relative abundance of species with a warmer thermal niche were observed in response to warmer summer temperatures using all three methods; however, effect sizes were greater over broadscale spatial gradients relative to either temporal variability in summer temperature within a site or summer temperature increases induced by experimental warming. The effect sizes for change over time within a site and with experimental warming were nearly identical. These results support the view that inferences based on space-for-time substitution overestimate the magnitude of responses to contemporary climate warming, because spatial gradients reflect long-term processes. In contrast, in situ experimental warming and monitoring approaches yield consistent estimates of the magnitude of response of plant communities to climate warming.

Discover hidden collaborations