Publications
Below are publications associated with the Southwest Biological Science Center's research.
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Assessing predation risks for small fish in a large river ecosystem between contrasting habitats and turbidity conditions
This study examined predation risk for juvenile native fish between two riverine shoreline habitats, backwater and debris fan, across three discrete turbidity levels (low, intermediate, high) to understand environmental risks associated with habitat use in a section of the Colorado River in Grand Canyon, AZ. Inferences are particularly important to juvenile native fish, including the federally end
Authors
Michael J. Dodrill, Michael D. Yard, William E. Pine
Using climate, energy, and spatial-based hypotheses to interpret macroecological patterns of North America chelonians
Our study investigates how factors, such as latitude, productivity, and several environmental variables, influence contemporary patterns of the species richness in North American turtles. In particular, we test several hypotheses explaining broad-scale species richness patterns on several species richness data sets: (i) total turtles, (ii) freshwater turtles only, (iii) aquatic turtles, (iv) terre
Authors
Joshua R. Ennen, Mickey Agha, Wilfredo A. Matamoros, Sarah C. Hazzard, Jeffrey E. Lovich
A morphological review of subspecies of the Asian box turtle, Cuora amboinensis (Testudines, Geomydidae)
The turtle Cuora amboinensis has an extensive distribution covering most of southern mainland Asia, Indonesia, and extending to the Philippine Islands. Unlike many species, C. amboinensis occurs on both sides of Wallace's Line separating Asian and Australian flora and fauna. Four subspecies are currently recognized; Cuora a. kamaroma (southern continental Asia, Java and the northern Philippines [i
Authors
Carl H. Ernst, Arndt F. Laemmerzahl, Jeffrey E. Lovich
Variability in rainfall at monitoring stations and derivation of a long-term rainfall intensity record in the Grand Canyon Region, Arizona, USA
In this study, we examine rainfall datasets of varying temporal length, resolution, and spatial distribution to characterize rainfall depth, intensity, and seasonality for monitoring stations along the Colorado River within Marble and Grand Canyons. We identify maximum separation distances between stations at which rainfall measurements might be most useful for inferring rainfall characteristics a
Authors
Joshua J. Caster, Joel B. Sankey
Semi-arid vegetation response to antecedent climate and water balance windows
Questions
Can we improve understanding of vegetation response to water availability on monthly time scales in semi-arid environments using remote sensing methods? What climatic or water balance variables and antecedent windows of time associated with these variables best relate to the condition of vegetation? Can we develop credible near-term forecasts from climate data that can be used to prepa
Authors
David P. Thoma, Seth M. Munson, Kathryn M. Irvine, Dana L. Witwicki, Erin Bunting
Low soil moisture during hot periods drives apparent negative temperature sensitivity of soil respiration in a dryland ecosystem: A multi-model comparison
Arid and semiarid ecosystems (drylands) may dominate the trajectory of biosphere-to-atmosphere carbon (C) exchange, and understanding dryland CO2 efflux is important for C cycling at the global-scale. However, unknowns remain regarding how temperature and moisture interact to regulate dryland soil respiration (R s ), while ‘islands of fertility’ in drylands create spatially heterogeneous R s . At
Authors
Colin Tucker, Sasha C. Reed
Spatially explicit rangeland erosion monitoring using high-resolution digital aerial imagery
Nearly all of the ecosystem services supported by rangelands, including production of livestock forage, carbon sequestration, and provisioning of clean water, are negatively impacted by soil erosion. Accordingly, monitoring the severity, spatial extent, and rate of soil erosion is essential for long-term sustainable management. Traditional field-based methods of monitoring erosion (sediment traps,
Authors
Jeffrey K. Gillan, Jason W. Karl, Nichole N. Barger, Ahmed Elaksher, Michael C. Duniway
Available data support protection of the Southwestern Willow Flycatcher under the Endangered Species Act
Zink (2015) argued there was no evidence for genetic, morphological, or ecological differentiation between the federally endangered Southwestern Willow Flycatcher (Empidonax traillii extimus) and other Willow Flycatcher subspecies. Using the same data, we show there is a step-cline in both the frequency of a mtDNA haplotype and in plumage variation roughly concordant with the currently recognized
Authors
Tad C. Theimer, Aaron D. Smith, Sean M. Mahoney, Kirsten E. Ironside
Cumulative drought and land-use impacts on perennial vegetation across a North American dryland region
Question
The decline and loss of perennial vegetation in dryland ecosystems due to global change pressures can alter ecosystem properties and initiate land degradation processes. We tracked changes of perennial vegetation using remote sensing to address the question of how prolonged drought and land-use intensification have affected perennial vegetation cover across a desert region in the early
Authors
Seth M. Munson, A. Lexine Long, Cynthia Wallace, Robert H. Webb
A review of precipitation and temperature control on seedling emergence and establishment for ponderosa and lodgepole pine forest regeneration
The persistence of ponderosa pine and lodgepole pine forests in the 21st century depends to a large extent on how seedling emergence and establishment are influenced by driving climate and environmental variables, which largely govern forest regeneration. We surveyed the literature, and identified 96 publications that reported data on dependent variables of seedling emergence and/or establishment
Authors
Matthew Petrie, A.M. Wildeman, John B. Bradford, R.M. Hubbard, W.K. Lauenroth
Demographic response of northern spotted owls to barred owl removal
Federally listed as threatened in 1990 primarily because of habitat loss, the northern spotted owl (Strix occidentalis caurina) has continued to decline despite conservation efforts resulting in forested habitat being reserved throughout its range. Recently, there is growing evidence the congeneric invasive barred owl (Strix varia) may be responsible for the continued decline primarily by excludin
Authors
V. Lowell Diller, Keith A. Hamm, Desiree A Early, David W Lamphear, Katie M. Dugger, Charles B. Yackulic, Carl J. Schwarz, Peter C. Carlson, Trent L. McDonald
Nutrient resorption helps drive intra-specific coupling of foliar nitrogen and phosphorus under nutrient-enriched conditions
Aims
Plant biomass growth, storage, and decomposition connect nitrogen (N) and phosphorus (P) cycles, yet we know relatively little about the dynamics of such coupling under nutrient enriched conditions, and our understanding of the interactive relationships between plant N and P in drylands remains particularly poor.
Methods
In a semiarid steppe of northern China, we examined the effects of si
Authors
Lü Xiao-Tao, Sasha C. Reed, Qiang Yu, Xing-Guo Han