Southwest Biological Science Center

Filter Total Items: 563
Channel mapping river miles 29–62 of the Colorado River in Grand Canyon National Park, Arizona, May 2009
Year Published: 2017

Channel mapping river miles 29–62 of the Colorado River in Grand Canyon National Park, Arizona, May 2009

Bathymetric, topographic, and grain-size data were collected in May 2009 along a 33-mi reach of the Colorado River in Grand Canyon National Park, Arizona. The study reach is located from river miles 29 to 62 at the confluence of the Colorado and Little Colorado Rivers. Channel bathymetry was mapped using multibeam and singlebeam echosounders, subaerial topography was mapped using ground-based...

Kaplinski, Matt; Hazel, Joseph E.; Grams, Paul E.; Kohl, Keith; Buscombe, Daniel D.; Tusso, Robert B.
Kaplinski, M., Hazel, J.E., Jr., Grams, P.E., Kohl, Keith, Buscombe, D.D., and Tusso, R.B., 2017, Channel mapping river miles 29–62 of the Colorado River in Grand Canyon National Park, Arizona, May 2009: U.S. Geological Survey Open-File Report 2017–1030, 35 p., https://doi.org/10.3133/ofr20171030.
Changes in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon
Year Published: 2017

Changes in community-level riparian plant traits over inundation gradients, Colorado River, Grand Canyon

Comparisons of community-level functional traits across environmental gradients have potential for identifying links among plant characteristics, adaptations to stress and disturbance, and community assembly. We investigated community-level variation in specific leaf area (SLA), plant mature height, seed mass, stem specific gravity (SSG), relative cover of C4 species, and total plant cover over...

McCoy-Sulentic, Miles; Kolb, Thomas; Merritt, David; Palmquist, Emily C.; Ralston, Barbara; Sarr, Daniel; Shafroth, Patrick B.
McCoy-Sulentic, M.E., Kolb, T.E., Merritt, D.M., Palmquist, E., Ralston, B.E., Sarr, D.A., and Shafroth, P.B., 2017, Changes in Community-Level Riparian Plant Traits over Inundation Gradients, Colorado River, Grand Canyon: Wetlands, online, doi:10.1007/s13157-017-0895-3.
Importance of the 2014 Colorado River Delta pulse flow for migratory songbirds: Insights from foraging behavior
Year Published: 2017

Importance of the 2014 Colorado River Delta pulse flow for migratory songbirds: Insights from foraging behavior

The Lower Colorado River provides critical riparian areas in an otherwise arid region and is an important stopover site for migrating landbirds. In order to reverse ongoing habitat degradation due to drought and human-altered hydrology, a pulse flow was released from Morelos Dam in spring of 2014, which brought surface flow to dry stretches of the Colorado River in Mexico.

Darrah, Abigail J.; Greeney, Harold F.; Van Riper, Charles
Darrah, Abigail .J., Harold F. Greeney and Charles van Riper III. 2016. Importance of the 2014 Colorado River Delta pulse flow for migratory songbirds: Insights from foraging behavior. Ecological Engineering. early online. Full cite to follow.
Pushing precipitation to the extremes in distributed experiments: Recommendations for simulating wet and dry years
Year Published: 2017

Pushing precipitation to the extremes in distributed experiments: Recommendations for simulating wet and dry years

Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multiyear droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records) is increasing, there is a clear need to identify...

Knapp, Alan K.; Avolio, Meghan L.; Beier, Claus; Carroll, Charles J.W.; Collins, Scott L.; Dukes, Jeffrey S.; Fraser, Lauchlan H.; Griffin-Nolan, Robert J.; Hoover, David L.; Jentsch, Anke; Loik, Michael E.; Phillips, Richard P.; Post, Alison K.; Sala, Osvaldo E.; Slette, Ingrid J.; Yahdjian, Laura; Smith, Melinda D.
Knapp, A.K., M.L. Avolio, C. Beier, C.J.W. Carroll, S.L. Collins, J.S. Dukes,, L. H. Fraser, R..J. Griffin-Nolan, D. L. Hoover, A. Jentsch, M.E. Loik, R. P. Phillps, A.K. Post, O.E. Sala, I.J. Slette, L. Yahdjian and M.D. Smith. (2016), Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years. Glob Change Biol. doi:10.1111/gcb.13504 http://onlinelibrary.wiley.com/doi/10.1111/gcb.13504/full
Long-term fish monitoring in large rivers: Utility of “benchmarking” across basins
Year Published: 2017

Long-term fish monitoring in large rivers: Utility of “benchmarking” across basins

In business, benchmarking is a widely used practice of comparing your own business processes to those of other comparable companies and incorporating identified best practices to improve performance. Biologists and resource managers designing and conducting monitoring programs for fish in large river systems tend to focus on single river basins or segments of large rivers, missing opportunities...

Ward, David L.; Casper, Andrew F.; Counihan, Timothy D.; Bayer, Jennifer M.; Waite, Ian R.; Kosovich, John J.; Chapman, Colin; Irwin, Elise R.; Sauer, Jennifer S.; Ickes, Brian; McKerrow, Alexa
Ward, D.L., Casper, A.F., Counihan, T.D., Bayer, J.M., Waite, I.R., Kosovich, J.J., Chapman, C.G., Irwin, E.R., Sauer, J.S., Iches, B.S., and McKerrow, A.J., 2017,Long-Term Fish Monitoring in Large Rivers: Utility of “Benchmarking” across Basins: Fisheries, no. 42, v. 2, p
Differential responses of dinitrogen fixation, diazotrophic cyanobacteria and ammonia oxidation reveal a potential warming-induced imbalance of the N-cycle in biological soil crusts
Year Published: 2017

Differential responses of dinitrogen fixation, diazotrophic cyanobacteria and ammonia oxidation reveal a potential warming-induced imbalance of the N-cycle in biological soil crusts

N2 fixation and ammonia oxidation (AO) are the two most important processes in the nitrogen (N) cycle of biological soil crusts (BSCs). We studied the short-term response of acetylene reduction assay (ARA) rates, an indicator of potential N2 fixation, and AO rates to temperature (T, -5°C to 35°C) in BSC of different successional stages along the BSC ecological succession and geographic origin (...

Zhou, Xiaobing; Smith, Hilda J.; Giraldo Silva, Ana; Belnap, Jayne; Garcia-Pichel, Ferran
Aridity increases below-ground niche breadth in grass communities
Year Published: 2017

Aridity increases below-ground niche breadth in grass communities

Aridity is an important environmental filter in the assembly of plant communities worldwide. The extent to which root traits mediate responses to aridity, and how they are coordinated with leaf traits, remains unclear. Here, we measured variation in root tissue density (RTD), specific root length (SRL), specific leaf area (SLA), and seed size within and among thirty perennial grass communities...

Butterfield, Bradley J.; Bradford, John B.; Munson, Seth M.; Gremer, Jennifer R.
Butterfield, B.J., Bradford, J.B., Munson, S.M., Gremer, J.R., 2017, Aridity increases below-ground niche breadth in grass communities: Plant Ecology, v. (online), http://dx.doi.org/10.1007/s11258-016-0696-4 and http://link.springer.com/article/10.1007/s11258-016-0696-4.
Climate change reduces extent of temperate drylands and intensifies drought in deep soils
Year Published: 2017

Climate change reduces extent of temperate drylands and intensifies drought in deep soils

Drylands cover 40% of the global terrestrial surface and provide important ecosystem services. While drylands as a whole are expected to increase in extent and aridity in coming decades, temperature and precipitation forecasts vary by latitude and geographic region suggesting different trajectories for tropical, subtropical, and temperate drylands. Uncertainty in the future of tropical and...

Schlaepfer, Daniel R.; Bradford, John B.; Lauenroth, William K.; Munson, Seth M.; Tietjen, Britta; Hall, Sonia A.; Wilson, Scott D.; Duniway, Michael C.; Jia, Gensuo; Pyke, David A.; Lkhagva, Ariuntsetseg; Jamiyansharav, Khishigbayar
Schlaepfer, D.R., Bradford, J.B., Lauenroth, W.K., Munson, S.M., Tietjen, B., Hall, S.A., Wilson, S.D., Duniway, M.C., Jia, G., Pyke, D.A., Lkhagva, A., and Khishigbayar, J., 2017, Climate change reduces extent of temperate drylands and intensifies drought in deep soils: Nature Communications, no. 8, http://www.nature.com/articles/ncomms14196#abstract and http://dx.doi.org/10.1038/ncomms14196.
Ecosystem implications of conserving endemic versus eradicating introduced large herbivores in the Galapagos Archipelago
Year Published: 2017

Ecosystem implications of conserving endemic versus eradicating introduced large herbivores in the Galapagos Archipelago

Restoration of damaged ecosystems through invasive species removal and native species conservation is an increasingly common practice in biodiversity conservation. Estimating the degree of ecosystem response attributable specifically to eradication of exotic herbivores versus restoration of native herbivores is often difficult and is complicated by concurrent temporal changes in other factors,...

Bastille-Rousseau, Guillaume; Gibbs, James P.; Campbell, Karl; Yackulic, Charles B.; Blake, Stephen
Bastille-Rousseau, G., Gibbs, J.P., Campbell, K, Yackulic, C.B., and Blake, S., 2017, Ecosystem implications of conserving endemic versus eradicating introduced large herbivores in the Galapagos Archipelago: Biological Conservation, n. 209, p. 1-10, http://dx.doi.org/10.1016/j.biocon.2017.02.015
Colorado River fish monitoring in Grand Canyon, Arizona; 2002–14 humpback chub aggregations
Year Published: 2017

Colorado River fish monitoring in Grand Canyon, Arizona; 2002–14 humpback chub aggregations

The humpback chub (Gila cypha) is an endangered cyprinid species endemic to the Colorado River. The largest remaining population of the species spawns and rears in the Little Colorado River in Grand Canyon. Construction and operation of Glen Canyon Dam has altered the main-stem Colorado River in Glen and Grand Canyons. Cold, clear water releases from the dam result in a river that is generally...

Persons, William R.; Van Haverbeke, David R.; Dodrill, Michael J.
Persons, W.R., Van Haverbeke, D.R., and Dodrill, M.J., 2017, Colorado River fish monitoring in Grand Canyon, Arizona; 2002–14 humpback chub aggregations: U.S. Geological Survey Open-File Report 2016–1177, 43 p., https://doi.org/10.3133/ofr20161177.
NDVI, scale invariance and the modifiable areal unit problem: An assessment of vegetation in the Adelaide Parklands
Year Published: 2017

NDVI, scale invariance and the modifiable areal unit problem: An assessment of vegetation in the Adelaide Parklands

This research addresses the question as to whether or not the Normalised Difference Vegetation Index (NDVI) is scale invariant (i.e. constant over spatial aggregation) for pure pixels of urban vegetation. It has been long recognized that there are issues related to the modifiable areal unit problem (MAUP) pertaining to indices such as NDVI and images at varying spatial resolutions. These issues...

Nouri, Hamideh; Anderson, Sharolyn; Sutton, Paul; Beecham, Simon; Nagler, Pamela L.; Jarchow, Christopher J; Roberts, Dar A.
Nouri, Hamideh, Sharolyn Anderson, Paul Sutton, Simon Beecham, Pamela Nagler, Christopher J. Jarchow, Dar A. Roberts. 2017. NDVI, scale invariance and the modifiable areal unit problem: An assessment of vegetation in the Adelaide Parklands. Science of The Total Environment. Volumes 584–585, 15 April 2017, Pages 11–18 dx.doi.org/10.1016/j.scitotenv.2017.01.130 http://www.sciencedirect.com/science/article/pii/S0048969717301407
A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river
Year Published: 2017

A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river

Lateral flow separation occurs in rivers where banks exhibit strong curvature. In canyon-boundrivers, lateral recirculation zones are the principal storage of fine-sediment deposits. A parallelized,three-dimensional, turbulence-resolving model was developed to study the flow structures along lateralseparation zones located in two pools along the Colorado River in Marble Canyon. The model employs...

Alvarez, Laura V.; Schmeeckle, Mark W.; Grams, Paul E.
Alvarez, L.A., Schmeeckle, M.W., and Grams, P.E., 2017, A detached eddy simulation model for the study of lateralseparation zones along a large canyon-bound river: Journal of Geophysical Research: Earth Surface, online, p. 1-25, 10.1002/2016JF003895