Collection of published works by members of the Southwest Chapter of the Ecological Society of America

Description

This collection was established to engage Southwest Chapter members and facilitate interaction between them and to enhance discovery of relevant ecological research.

latest article added on December 2013

ArticleFirst AuthorPublished
RANK CLOCKS AND PLANT COMMUNITY DYNAMICSCollins, Scott L.2008

RANK CLOCKS AND PLANT COMMUNITY DYNAMICS

Keywords

community dynamics; proportional persistence; rank-abundance curves; rank clock; rank shifts; species diversity; temporal dynamics

Abstract

Summarizing complex temporal dynamics in communities is difficult to achieve in a way that yields an intuitive picture of change. Rank clocks and rank abundance statistics provide a graphical and analytical framework for displaying and quantifying community dynamics. We used rank clocks, in which the rank order abundance for each species is plotted over time in temporal clockwise direction, to display temporal changes in species abundances and richness. We used mean rank shift and proportional species persistence to quantify changes in community structure in long-term data sets from fertilized and control plots in a late successional old field, frequently and infrequently burned tallgrass prairie, and Chihuahuan desert grassland and shrubland communities. Rank clocks showed that relatively constant species richness masks considerable temporal dynamics in relative species abundances. In the old field, fertilized plots initially experienced high mean rank shifts that stabilized rapidly below that of unfertilized plots. Rank shifts were higher in infrequently burned vs. annually burned tallgrass prairie and in desert grassland compared to shrubland vegetation. Proportional persistence showed that and grasslands were more dynamic than mesic grasslands. We conclude that rank clocks and rank abundance statistics provide important insights into community dynamics that are often hidden by traditional univariate approaches.

Authors

Collins, Scott L.; Suding, Katharine N.; Cleland, Elsa E.; Batty, Michael; Pennings, Steven C.; Gross, Katherine L.; Grace, James B.; Gough, Laura; Fargione, Joe E.; Clark, Christopher M.

Year Published

2008

Publication

Ecology

Locations
DOI

10.1890/07-1646.1

This article contributed by:

Ecological Society of America

New opportunities in ecological sensing using wireless sensor networksCollins, Scott L.2006

New opportunities in ecological sensing using wireless sensor networks

Keywords

No keywords available

Abstract

Measuring environmental variables at appropriate temporal and spatial scales remains an important challenge in ecological research. New developments in wireless sensors and sensor networks will free ecologists from a wired world and revolutionize our ability to study ecological systems at relevant scales. In addition, sensor networks can analyze and manipulate the data they collect, thereby moving data processing from the end user to the sensor network itself. Such embedded processing will allow sensor networks to perform data analysis procedures, identify outlier data, alter sampling regimes, and ultimately control experimental infrastructure. We illustrate this capability using a wireless sensor network, the Sensor Web, in a study of microclimate variation under shrubs in the Chihuahuan Desert. Using Sensor Web data, we propose simple analytical protocols for assessing data quality "on-the-fly" that can be programmed into sensor networks. The ecological community can influence the evolution of environmental sensor networks by working across disciplines to infuse new ideas into sensor network development.

Authors

Collins, Scott L.; Bettencourt, Luis M. A.; Hagberg, Aric; Brown, Renee F.; Moore, Douglas I.; Bonito, Greg; Delin, Kevin A.; Jackson, Shannon P.; Johnson, David W.; Burleigh, Scott C.; Woodrow, Richard R.; McAuley, J. Michael

Year Published

2006

Publication

Frontiers In Ecology And The Environment

Locations
DOI

10.1890/1540-9295(2006)4[402:NOIESU]2.0.CO;2

This article contributed by:

Ecological Society of America

Rangeland and pasture monitoring: an approach to interpretation of high-resolution imagery focused on observer calibration for repeatabilityDuniway, Michael C.2012

Rangeland and pasture monitoring: an approach to interpretation of high-resolution imagery focused on observer calibration for repeatability

Keywords

remote sensing, image interpretation, aerial photography, repeatability, assessment and monitoring, large-scale

Abstract

Collection of standardized assessment and monitoring data is critically important for supporting policy and management at local to continental scales. Remote sensing techniques, including image interpretation, have shown promise for collecting plant community composition and ground cover data efficiently. More work needs to be done, however, evaluating whether these techniques are sufficiently feasible, cost-effective, and repeatable to be applied in large programs. The goal of this study was to design and test an image-interpretation approach for collecting plant community composition and ground cover data appropriate for local and continental-scale assessment and monitoring of grassland, shrubland, savanna, and pasture ecosystems. We developed a geographic information system image-interpretation tool that uses points classified by experts to calibrate observers, including point-by-point training and quantitative quality control limits. To test this approach, field data and high-resolution imagery (∼3 cm ground sampling distance) were collected concurrently at 54 plots located around the USA. Seven observers with little prior experience used the system to classify 300 points in each plot into ten cover types (grass, shrub, soil, etc.). Good agreement among observers was achieved, with little detectable bias and low variability among observers (coefficient of variation in most plots  0.9), suggesting regression-based adjustments can be used to relate image and field data. This approach could extend the utility of expensive-to-collect field data by allowing it to serve as a validation data source for data collected via image interpretation.

Authors

Karl, Jason W., Duniway, Michael C., Schrader, Scott, Baquera, Noemi and Herrick, Jeffrey E.

Year Published

2012

Publication

Environmental Monitoring and Assessment

Locations
DOI

10.1007/s10661-011-2224-2

Assessing Impacts of Roads: Application of a Standard Assessment ProtocolDuniway, Michael C.2013

Assessing Impacts of Roads: Application of a Standard Assessment Protocol

Keywords

adaptive management, assessment, monitoring, off-highway vehicles, oil and gas, rangeland health

Abstract

Adaptive management of road networks depends on timely data that accurately reflect the impacts those systems are having on ecosystem processes and associated services. In the absence of reliable data, land managers are left with little more than observations and perceptions to support management decisions of road-associated disturbances. Roads can negatively impact the soil, hydrologic, plant, and animal processes on which virtually all ecosystem services depend. The Interpreting Indicators of Rangeland Health (IIRH) protocol is a qualitative method that has been demonstrated to be effective in characterizing impacts of roads. The goal of this study were to develop, describe, and test an approach for using IIRH to systematically evaluate road impacts across large, diverse arid and semiarid landscapes. We developed a stratified random sampling approach to plot selection based on ecological potential, road inventory data, and image interpretation of road impacts. The test application on a semiarid landscape in southern New Mexico, United States, demonstrates that the approach developed is sensitive to road impacts across a broad range of ecological sites but that not all the types of stratification were useful. Ecological site and road inventory strata accounted for significant variability in the functioning of ecological processes but stratification based on apparent impact did not. Analysis of the repeatability of IIRH applied to road plots indicates that the method is repeatable but consensus evaluations based on multiple observers should be used to minimize risk of bias. Landscape-scale analysis of impacts by roads of contrasting designs (maintained dirt or gravel roads vs. non- or infrequently maintained roads) suggests that future travel management plans for the study area should consider concentrating traffic on fewer roads that are well designed and maintained. Application of the approach by land managers will likely provide important insights into minimizing impacts of road networks on key ecosystem services.

Authors

Duniway, Michael C. and Herrick, Jeffrey E.

Year Published

2013

Publication

Rangeland Ecology & Management

Locations
DOI

10.2111/rem-d-11-00130.1

The High Water-Holding Capacity of Petrocalcic HorizonsDuniway, Michael C.2007

The High Water-Holding Capacity of Petrocalcic Horizons

Keywords

CHIHUAHUAN DESERT, SOIL-QUALITY, REPLACEMENT, CALICHE, PLANTS, ROCK

Abstract

Petrocalcic soil horizons occur in most arid and semiarid ecosystems around the world, often within the plant rooting zone. Little is known, however, about the water-holding characteristic of soils indurated with CaCO3. We conducted a replicated experiment to define the soil-water release curve (SWRC) for a range of petrocalcic horizon materials. Samples from both plugged and laminar zones of two Stage V petrocalcic horizons in southern New Mexico were characterized. Wetter soil-water potentials were measured using a pressure plate; more negative potentials (down to less than < -10 MPa) were measured using a chilled mirror water activity meter. Measured SWRC data were fitted to the van Genuchten equation. The SWRC methods used were found to be both reliable and repeatable. Plant-available water-holding capacity (AWHC) for desert species (with wilting point set at -4.0 MPa) ranged from 0.26 m3 m-3 in plugged zones to 0.06 m3 m-3 in some laminar zones in contrast to about 0.07 m3 m-3 in the loamy sand parent material. Correlation analyses across morphologies of AWHC and soil properties resulted in significant statistical relationships only with bulk density and porosity. The AWHC and CaCO3 content, however, were significantly negatively correlated within the laminar and positively correlated within the plugged petrocalcic horizon morphologies. Cementation by CaCO3 dramatically alters the water-holding characteristics of soils and understanding these horizons is crucial to understand patterns of soil water in desert systems throughout the world.

Authors

Duniway, Michael C., Herrick, Jeffrey E. and Monger, H. Curtis

Year Published

2007

Publication

Soil Science Society of America Journal

Locations
DOI

10.2136/sssaj2006.0267

Hierarchical analysis of vegetation dynamics over 71 years: soil-rainfall interactions in a Chihuahuan Desert ecosystemBrowning, Dawn M.2012

Hierarchical analysis of vegetation dynamics over 71 years: soil-rainfall interactions in a Chihuahuan Desert ecosystem

Keywords

aerial photography; Chihuahuan Desert, New Mexico, USA; cross-scale linkages; ecological-state mapping; hierarchy theory; Jornada Basin LTER; object-based change detection; petrocalcic soil; Prosopis glandulosa; shrub patch dynamics; shrub proliferation; soil depth

Abstract

Proliferation of woody plants in grasslands and savannas is a persistent problem globally. This widely observed shift from grass to shrub dominance in rangelands worldwide has been heterogeneous in space and time largely due to cross-scale interactions among soils, climate, and land-use history. Our objective was to use a hierarchical framework to evaluate the relationship between spatial patterns in soil properties and long-term shrub dynamics in the northern Chihuahuan Desert of New Mexico, USA. To meet this objective, shrub patch dynamics from 1937 to 2008 were characterized at patch and landscape scales using historical imagery and a recent digital soils map. Effects of annual precipitation on patch dynamics on two soils revealed strong correlations between shrub growth on deep sandy soils and above-average rainfall years (r = 0.671, P = 0.034) and shrub colonization and below-average rainfall years on shallow sandy soils (r = 0.705, P = 0.023). Patch-level analysis of demographic patterns revealed significant differences between shrub patches on deep and shallow sandy soils during periods of above-and below-average rainfall. Both deep and shallow sandy soils exhibited low shrub cover in 1937 (1.0% +/- 2.3% and 0.3% +/- 1.3%, respectively [mean +/- SD]) and were characterized by colonization or appearance of new patches until 1960. However, different demographic responses to the cessation of severe drought on the two soils and increased frequency of wet years after 1960 have resulted in very different endpoints. In 2008 a shrubland occupied the deep sandy soils with cover at 19.8% +/- 9.1%, while a shrub-dominated grassland occurred on the shallow sandy soils with cover at 9.3% +/- 7.2%. Present-day shrub vegetation constitutes a shifting mosaic marked by the coexistence of patches at different stages of development. Management implications of this long-term multi-scale assessment of vegetation dynamics support the notion that soil properties may constrain grassland remediation. Such efforts on sandy soils should be focused on sites characterized by near-surface water-holding capacity, as those lacking available water-holding capacity in the shallow root zone pose challenges to grass recovery and survival.

Authors

Browning, Dawn M.; Duniway, Michael C.; Laliberte, Andrea S.; Rango, Albert

Year Published

2012

Publication

Ecological Applications

Locations
This article contributed by:

Ecological Society of America

Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran DesertHall, Sharon J.2011

Ecosystem response to nutrient enrichment across an urban airshed in the Sonoran Desert

Keywords

Ambrosia; arid ecosystem; Larrea tridentata; N deposition; nitrogen fertilization; Pectocarya spp.; phosphorus; Sonoran Desert, Arizona, USA; urban environments; winter ephemeral annual plants

Abstract

Rates of nitrogen (N) deposition have increased in arid and semiarid ecosystems, but few studies have examined the impacts of long-term N enrichment on ecological processes in deserts. We conducted a multiyear, nutrient-addition study within 15 Sonoran Desert sites across the rapidly growing metropolitan area of Phoenix, Arizona (USA). We hypothesized that desert plants and soils would be sensitive to N enrichment, but that these effects would vary among functional groups that differ in terms of physiological responsiveness, proximity to surface N sources, and magnitude of carbon (C) or water limitation. Inorganic N additions augmented net potential nitrification in soils, moreso than net potential N mineralization, highlighting the important role of nitrifying microorganisms in the nitrate economy of drylands. Winter annual plants were also responsive to nutrient additions, exhibiting a climate-driven cascade of resource limitation, from little to no production in seasons of low rainfall (winter 2006 and 2007), to moderate N limitation with average precipitation (winter 2009), to limitation by both N and P in a season of above-normal rainfall (winter 2008). Herbaceous production is a potentially important mechanism of N retention in arid ecosystems, capable of immobilizing an amount equal to or greater than that deposited annually to soils in this urban airshed. However, interannual variability in precipitation and abiotic processes that limit the incorporation of detrital organic matter into soil pools may limit this role over the long term. In contrast, despite large experimental additions of N and P over four years, growth of Larrea tridentata, the dominant perennial plant of the Sonoran Desert, was unresponsive to nutrient enrichment, even during wet years. Finally, there did not appear to be strong ecological interactions between nutrient addition and location relative to the city, despite the nearby activity of nearly four million people, perhaps due to loss or transfer pathways that limit long-term N enrichment of ecosystems by the urban atmosphere.

Authors

Hall, Sharon J.; Sponseller, Ryan A.; Grimm, Nancy B.; Huber, David; Kaye, Jason P.; Clark, Christopher; Collins, Scott L.

Year Published

2011

Publication

Ecological Applications

Locations
DOI

10.1890/10-0758.1

This article contributed by:

Ecological Society of America

Spatial variation in remnant grasses after a grassland-to-shrubland state change: Implications for restorationPeters, Debra P. C.2006

Spatial variation in remnant grasses after a grassland-to-shrubland state change: Implications for restoration

Keywords

Bouteloua eriopoda; Larrea tridentata; Flourensia cernua; perennial grasslands; shrub invasion

Abstract

Around the world rangelands that have been degraded, such as historical desert grasslands now dominated by woody shrubs, are resistant to restoration efforts. The goal of this descriptive research was to examine the potential for black grama(Bouteloua eriopoda [Torr.] Torr.) recovery by remnant plants in a degraded area as a function of plant location across a landscape. Our objectives were 1) to document the historical dominant vegetation as a perennial grassland and determine broad-scale changes in dominance through time and 2) to examine fine-scale patterns of black grama presence and basal area with respect to microenvironmental conditions that indicate the landscape positions favorable for restoration. Historical vegetation maps starting in 1858, a field survey in 2002-2003 of the location of all individual black grama plants in a 29-ha area, and spatial data layers in a geographic information system were used to address these objectives. Upland grasses, including black grama, dominated the study site in 1858, although tarbush (Flourensia cernua DC.) was the dominant species by 1915, and creosotebush (Larrea tridentata [DC.] Cov.) is the current dominant. A total of 3 334 black grama plants were found for an average density of 0.01 plants . m(-2). High spatial variation was found in the occurrence and basal area of black grama plants that was related to water availability rather than livestock grazing: most plants were found in or adjacent to an arroyo (67%), at a northern aspect (47%), and outside experimental exclosures established in 1930 (43%). Largest average basal areas were found in the livestock exclosure, and in general, average basal area was not related with aspect or canopy microsite. These remnant plants can be used as propagule sources in restoration efforts, and information on microsite conditions for black grama survival can be used to improve restoration potential for similar sites.

Authors

Peters, Debra P. C.; Mariotto, Isabella; Havstad, Kris M.; Murray, Leigh W.

Year Published

2006

Publication

Rangeland Ecology & Management

Locations
Additional Information:

http://srmjournals.org/doi/abs/10.2111/05-202R1.1

Using Unmanned Aerial Vehicles for Rangelands: Current Applications and Future PotentialsRango, Albert2006

Using Unmanned Aerial Vehicles for Rangelands: Current Applications and Future Potentials

Keywords

No keywords available

Abstract

High resolution aerial photographs have important rangeland applications, such as monitoring vegetation change, developing grazing strategies, determining rangeland health, and assessing remediation treatment effectiveness. Acquisition of high resolution images by Unmanned Aerial Vehicles (UAVs) has certain advantages over piloted aircraft missions, including lower cost, improved safety, flexibility in mission planning, and closer proximity to the target. Different levels of remote sensing data can be combined to provide more comprehensive information: 15–30 m resolution imaging from space-borne sensors for determining uniform landscape units; < 1 m satellite or aircraft data to assess the pattern of ecological states in an area of interest; 5 cm UAV images to measure gap and patch sizes as well as percent bare soil and vegetation ground cover; and < 1 cm ground-based boom photography for ground truth or reference data. Two parallel tracks of investigation are necessary: one that emphasizes the utilization of the most technically advanced sensors for research, and a second that emphasizes the minimization of costs and the maximization of simplicity for monitoring purposes. We envision that in the future, resource management agencies, rangeland consultants, and private land managers should be able to use small, lightweight UAVs to satisfy their needs for acquiring improved data at a reasonable cost, and for making appropriate management decisions.

Authors

Bestelmeyer, Brandon, Herrick, Jeffrey E., Laliberte, Andrea, Rango, Albert, Steele, Caiti, Schmugge, Thomas, Roanhorse, Abigail and Jenkins, Vince

Year Published

2006

Publication

Environmental Practice

Locations
DOI

10.1017/S1466046606060224

State-and-Transition Models for Heterogeneous Landscapes: A Strategy for Development and ApplicationBestelmeyer, Brandon T.2009

State-and-Transition Models for Heterogeneous Landscapes: A Strategy for Development and Application

Keywords

climate, dynamic soil properties, ecological sites, inventory, monitoring, quantile regression, soils, state-and-transition models, threshold

Abstract

Interpretation of assessment and monitoring data requires information about how reference conditions and ecological resilience vary in space and time. Reference conditions used as benchmarks are often specified via potential-based land classifications (e.g., ecological sites) that describe the plant communities potentially observed in an area based on soil and climate. State-and-transition models (STMs) coupled to ecological sites specify indicators of ecological resilience and thresholds. Although general concepts surrounding STMs and ecological sites have received increasing attention, strategies to apply and quantify these concepts have not. In this paper, we outline concepts and a practical approach to potential-based land classification and STM development. Quantification emphasizes inventory techniques readily available to natural resource professionals that reveal processes interacting across spatial scales. We recommend a sequence of eight steps for the co-development of ecological sites and STMs, including 1) creation of initial concepts based on literature and workshops; 2) extensive, low-intensity traverses to refine initial concepts and to plan inventory; 3) development of a spatial hierarchy for sampling based on climate, geomorphology, and soils; 4) stratified medium-intensity inventory of plant communities and soils across a broad extent and with large sample sizes; 5) storage of plant and soil data in a single database; 6) model-building and analysis of inventory data to test initial concepts; 7) support and/or refinement of concepts; and 8) high-intensity characterization and monitoring of states. We offer a simple example of how data assembled via our sequence are used to refine ecological site classes and STMs. The linkage of inventory to expert knowledge and site-based mechanistic experiments and monitoring provides a powerful means for specifying management hypotheses and, ultimately, promoting resilience in grassland, shrubland, savanna, and forest ecosystems.

Authors

Herrick, Jeffrey E., Bestelmeyer, Brandon T., Havstad, Kris M., Tugel, Arlene J., Peacock, George L., Robinett, Daniel G., Shaver, Pat L., Brown, Joel R. and Sanchez, Homer

Year Published

2009

Publication

Rangeland Ecology & Management

Locations
DOI

10.2111/08-146

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