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
Geographic searching for ecological studies: a new frontierKarl, Jason W.2013

Geographic searching for ecological studies: a new frontier

Keywords

No keywords available

Abstract

No abstract available

Authors

Karl, Jason W., Gillan, Jeffrey K. and Herrick, Jeffrey E.

Year Published

2013

Publication

Trends in Ecology & Evolution

Locations
    DOI

    10.1016/j.tree.2013.05.001

    Rangeland Health Attributes and Indicators for Qualitative AssessmentPyke, David A.2002

    Rangeland Health Attributes and Indicators for Qualitative Assessment

    Keywords

    alexander, b, bestelmeyer, biological integri-, authors wish to, w, usgs and ars jointly, ty, thank drs, soil stability, nrcs, m, l, krueger, karl, j, inventory, infiltration, hydrologic function, funded this project, erosion, eddleman, ecosystem status, c, blm

    Abstract

    Panels of experts from the Society for Range Management and the National Research Council proposed that status of rangeland ecosystems could be ascertained by evaluating an ecological site’s potential to conserve soil resources and by a series of indicators for ecosystem processes and site stability. Using these recommendations as a starting point, we developed a rapid, qualitative method for assessing a moment-in-time status of rangelands. Evaluators rate 17 indicators to assess 3 ecosystem attributes (soil and site stability, hydrologic function, and biotic integrity) for a given location. Indicators include rills, water flow patterns, pedestals and terracettes, bare ground, gullies, wind scour and depositional areas, litter movement, soil resistance to erosion, soil surface loss or degradation, plant composition relative to infiltration, soil compaction, plant functional/structural groups, plant mortality, litter amount, annual production, invasive plants, and reproductive capability. In this paper, we detail the development and evolution of the technique and introduce a modified ecological reference worksheet that documents the expected presence and amount of each indicator on the ecological site. In addition, we review the intended applications for this technique and clarify the differences between assessment and monitoring that lead us to recommend this technique be used for moment-in-time assessments and not be used for temporal monitoring of rangeland status. Lastly, we propose a mechanism for adapting and modifying this technique to reflect improvements in understanding of ecosystem processes. We support the need for quantitative measures for monitoring rangeland health and propose some measures that we believe may address some of the 17 indicators.

    Authors

    Pyke, David A., Herrick, Jeffrey E., Shaver, Patrick and Pellant, Mike

    Year Published

    2002

    Publication

    Journal of Range Management

    Locations
      DOI

      10.2307/4004002

      Spatial patterns of grassland-shrubland state transitions: a 74 year record on grazed and protected areasBrowning, Dawn2014

      Spatial patterns of grassland-shrubland state transitions: a 74 year record on grazed and protected areas

      Keywords

      point pattern analysis, spatial ecology, pair correlation function, Ripley’s K, Moran’s I, spatial autocorrelation, LISA, livestock exclusion, Sonoran Desert, Prosopis velutina

      Abstract

      Tree and shrub abundance has increased in many grasslands, causing changes in ecosystem carbon and nitrogen pools that are related to patterns of woody plant distribution. However, with regard to spatial patterns, little is known about (i) how they develop; (ii) how they are influenced by grazing; or (iii) the extent to which intraspecific interactions dictate them. We addressed these questions by quantifying changes in the spatial distribution of Prosopis velutina (mesquite) shrubs over 74 years on grazed and protected grasslands. Livestock are effective agents of mesquite dispersal and mesquite has lateral roots extending well beyond its canopy. We therefore hypothesized that mesquite distributions would be (a) random on grazed areas and clustered on protected areas; and (b) that clustered or random distributions at early stages of encroachment would give way to regular distributions as stands matured and density-dependent interactions intensified. Assessments in 1932, 1948 and 2006 supported the first hypothesis, but we found no support for the second. In fact, clustering intensified with time on the protected area and the pattern remained random on the grazed site. Although shrub density increased on both areas between 1932 and 2006, we saw no progression toward a regular distribution indicative of density-dependent interactions. We propose that processes related to seed dispersal, grass-shrub seedling interactions, and hydrological constraints on shrub size interact to determine vegetation structure in grassland-to-shrubland state changes with implications for ecosystem function and management

      Authors

      Browning, Dawn, Franklin, Janet, Archer, Steven R., Gillan, Jeffrey K. and Guertin, D.Phillip

      Year Published

      2014

      Publication

      Ecological Applications

      Locations
      DOI

      10.1890/13-2033.1

      This article contributed by:

      Ecological Society of America

      Interpretation of high-resolution imagery for detecting woodland cover composition change after fuels reduction treatmentsKarl, Jason W.2014

      Interpretation of high-resolution imagery for detecting woodland cover composition change after fuels reduction treatments

      Keywords

      image interpretation, rangeland monitoring, remote sensing, high-resolution, land cover, change detection

      Abstract

      The use of very high resolution (VHR; ground sampling distances < ~5cm) aerial imagery to estimate site vegetation cover and to detect changes from management has been well documented. However, as the purpose of monitoring is to document change over time, the ability to detect changes from imagery at the same or better level of accuracy and precision as those measured in situ must be assessed for image-based techniques to become reliable tools for ecosystem monitoring. Our objective with this study was to quantify the relationship between field-measured and image-interpreted changes in vegetation and ground cover measured one year apart in a savanna with increased woody vegetation cover in southern Utah, USA. The study area was subject to a variety of fuel removal treatments between 2009 and 2010. We measured changes in plant community composition and ground cover along transects in a control area and three different treatments prior to and following three woody removal. We compared these measurements to vegetation composition and change based on photo-interpretation of ~4 cm ground sampling distance imagery along similar transects. Estimates of cover were similar between field-based and image-interpreted methods in 2009 and 2010 for woody vegetation, no vegetation, herbaceous vegetation and litter (including woody litter). Image-interpretation slightly overestimated cover for woody vegetation and no-vegetation classes (average difference between methods of 1.34% and 5.85%) and tended to underestimate cover for herbaceous vegetation and litter (average difference of -5.18% and 0.27%), but the differences were significant only for litter cover in 2009. Level of agreement between the field-measurements and image-interpretation was good for woody vegetation and no-vegetation classes (r between 0.47 and 0.89), but generally poorer for herbaceous vegetation and litter (r between 0.18 and 0.81) likely due to differences in image quality by year and the difficulty in discriminating fine vegetation and litter in imagery. Our results show that image interpretation to detect vegetation changes has utility for monitoring fuels reduction treatments in terms of woody vegetation and bare ground. The benefits of this technique are that it provides objective and repeatable measurements of site conditions that could be implemented relatively inexpensively and easily without the need for highly specialized software or technical expertise. Perhaps the biggest limitations of image interpretation to monitoring fuels treatments are the difficulty in challenges in estimating litter and herbaceous vegetation cover and the sensitivity of herbaceous cover estimates to image quality and shadowing.

      Authors

      Karl, Jason W., Gillan, Jeffrey K., Barger, Nichole N., Herrick, Jeffrey E. and Duniway, Michael

      Year Published

      2014

      Publication

      Ecological Indicators

      Locations
      DOI

      10.1016/j.ecolind.2014.05.017

      Discovering Ecologically Relevant Knowledge from Published Studies through Geosemantic SearchingKarl, Jason W.2013

      Discovering Ecologically Relevant Knowledge from Published Studies through Geosemantic Searching

      Keywords

      georeferencing, metadata, semantic search, spatial distribution, knowledge discovery

      Abstract

      It is easier to search the globe for research on the genes of a local plant than it is to find local research on that plant’s ecology. As a result, ecologists are often unaware of published local research and unlikely to find relevant studies from similar environments worldwide. Location information in ecological studies can be harnessed to enable geographic knowledge searches and could be standardized to make searches more fruitful. To demonstrate this potential, we developed the JournalMap Web site (www.journalmap.org). Easy access to geographic distributions of knowledge opens new possibilities for using ecological research to detect and interpret ecological patterns, evaluate current ecological knowledge, and facilitate knowledge creation. We call on journals and publishers to support standard reporting of study locations in publications and metadata, and we advocate georeferencing past studies.

      Authors

      Karl, Jason W., Herrick, Jeffrey E., Unnasch, Robert, Gillan, Jeffrey K., Ellis, Erle C., Lutters, Wayne G. and Martin, Laura J.

      Year Published

      2013

      Publication

      BioScience

      Locations
        DOI

        10.1525/bio.2013.63.8.10

        Acquisition, Orthorectification, and Object-based Classification of Unmanned Aerial Vehicle (UAV) Imagery for Rangeland MonitoringLaliberte, Andrea S.2010

        Acquisition, Orthorectification, and Object-based Classification of Unmanned Aerial Vehicle (UAV) Imagery for Rangeland Monitoring

        Keywords

        No keywords available

        Abstract

        The use of unmanned aerial vehicles (UAVs) for natural resource applications has increased considerably in recent years due to their greater availability, the miniaturization of sensors, and the ability to deploy a UAV relatively quickly and repeatedly at low altitudes. We examine in this paper the potential of using a small UAV for rangeland inventory, assessment and monitoring. Imagery with a ground resolved distance of 8 cm was acquired over a 290 ha site in southwestern Idaho. We developed a semiautomated orthorectification procedure suitable for handling large numbers of small-footprint UAV images. The geometric accuracy of the orthorectified image mosaics ranged from 1.5 m to 2 m. We used object-based hierarchical image analysis to classify imagery of plots measured concurrently on the ground using standard rangeland monitoring procedures. Correlations between imageand ground-based estimates of percent cover resulted in r-squared values ranging from 0.86 to 0.98. Time estimates indicated a greater efficiency for the image-based method compared to ground measurements. The overall classification accuracies for the two image mosaics were 83 percent and 88 percent. Even under the current limitations of operating a UAV in the National Airspace, the results of this study show that UAVs can be used successfully to obtain imagery for rangeland monitoring, and that the remote sensing approach can either complement or replace some ground-based measurements. We discuss details of the UAV mission, image processing and analysis, and accuracy assessment.

        Authors

        Laliberte, Andrea S., Herrick, Jeffrey E., Rango, Albert and Winters, Craig

        Year Published

        2010

        Publication

        Photogrammetric Engineering & Remote Sensing

        Locations
        DOI

        10.14358/pers.76.6.661

        Vegetation Index Differencing for Broad-Scale Assessment of Productivity Under Prolonged Drought and Sequential High Rainfall ConditionsBrowning, Dawn2013

        Vegetation Index Differencing for Broad-Scale Assessment of Productivity Under Prolonged Drought and Sequential High Rainfall Conditions

        Keywords

        change detection, rangeland monitoring, Landsat, ecological state, state-and-transition models, phenology

        Abstract

        Spatially-explicit depictions of plant productivity over large areas are critical to monitoring landscapes in highly heterogeneous arid ecosystems. Applying radiometric change detection techniques we sought to determine whether: (1) differences between pre- and post-growing season spectral vegetation index values effectively identify areas of significant change in vegetation; and (2) areas of significant change coincide with altered ecological states. We differenced NDVI values, standardized difference values to Z-scores to identify areas of significant increase and decrease in NDVI, and examined the ecological states associated with these areas. The vegetation index differencing method and translation of growing season NDVI to Z-scores permit examination of change over large areas and can be applied by non-experts. This method identified areas with potential for vegetation/ecological state transition and serves to guide field reconnaissance efforts that may ultimately inform land management decisions for millions of acres of federal lands.

        Authors

        Browning, Dawn and Steele, Caitriana

        Year Published

        2013

        Publication

        Remote Sensing

        Locations
        DOI

        10.3390/rs5010327

        Unmanned aerial vehicle-based remote sensing for rangeland assessment, monitoring, and managementLaliberte, Andrea2009

        Unmanned aerial vehicle-based remote sensing for rangeland assessment, monitoring, and management

        Keywords

        Airborne remote sensing ; Unmanned aerial vehicles ; Data analysis ; Image processing ; Satellites

        Abstract

        Rangeland comprises as much as 70% of the Earth's land surface area. Much of this vast space is in very remote areas that are expensive and often impossible to access on the ground. Unmanned Aerial Vehicles (UAVs) have great potential for rangeland management. UAVs have several advantages over satellites and piloted aircraft: they can be deployed quickly and repeatedly; they are less costly and safer than piloted aircraft; they are flexible in terms of flying height and timing of missions; and they can obtain imagery at sub-decimeter resolution. This hyperspatial imagery allows for quantification of plant cover, composition, and structure at multiple spatial scales. Our experiments have shown that this capability, from an off-the-shelf mini-UAV, is directly applicable to operational agency needs for measuring and monitoring. For use by operational agencies to carry out their mandated responsibilities, various requirements must be met: an affordable and reliable platform; a capability for autonomous, low altitude flights; takeoff and landing in small areas surrounded by rugged terrain; and an easily applied data analysis methodology. A number of image processing and orthorectification challenges have been or are currently being addressed, but the potential to depict the land surface commensurate with field data perspectives across broader spatial extents is unrivaled.

        Authors

        Rango, Albert, Laliberte, Andrea, Herrick, Jeffrey E., Winters, Craig, Havstad, Kris, Steele, Caiti and Browning, Dawn

        Year Published

        2009

        Publication

        Journal of Applied Remote Sensing

        Locations
          DOI

          10.1117/1.3216822

          A Comparison of Cover Pole With Standard Vegetation Monitoring MethodsToledo P, David2010

          A Comparison of Cover Pole With Standard Vegetation Monitoring Methods

          Keywords

          assessment;gap intercept;habitat quality;monitoring;visual obstruction;wildlife habitat

          Abstract

          The ability of resource managers to make informed decisions regarding wildlife habitat could be improved with the use of existing data sets and the use of cost-effective, standardized methods to simultaneously quantify vertical and horizontal cover. We characterized vegetation structure of 3 semiarid plant communities to compare cover pole measurements, standard measurements of vegetation cover, composition, height, and the proportion of the soil surface exposed by large intercanopy gaps. We propose that a more versatile and interpretable description of wildlife habitat can be generated using a line-point intercept method together with measurements of vegetation height and the proportion of the soil surface exposed by large intercanopy gaps. © The Wildlife Society.

          Authors

          Toledo P, David, Herrick, Jeffrey E. and Abbott, Laurie B.

          Year Published

          2010

          Publication

          Journal of Wildlife Management

          Locations
          DOI

          10.2193/2009-136

          Interpretation of high-resolution imagery for detecting woodland cover composition change after fuels reduction treatmentsKarl, Jason W.2014

          Interpretation of high-resolution imagery for detecting woodland cover composition change after fuels reduction treatments

          Keywords

          image interpretation, rangeland monitoring, remote sensing, high-resolution, land cover, change detection

          Abstract

          The use of very high resolution (VHR; ground sampling distances < ~5cm) aerial imagery to estimate site vegetation cover and to detect changes from management has been well documented. However, as the purpose of monitoring is to document change over time, the ability to detect changes from imagery at the same or better level of accuracy and precision as those measured in situ must be assessed for image-based techniques to become reliable tools for ecosystem monitoring. Our objective with this study was to quantify the relationship between field-measured and image-interpreted changes in vegetation and ground cover measured one year apart in a Piñon and Juniper (P-J) woodland in southern Utah, USA. The study area was subject to a variety of fuel removal treatments between 2009 and 2010. We measured changes in plant community composition and ground cover along transects in a control area and three different treatments prior to and following P-J removal. We compared these measurements to vegetation composition and change based on photo-interpretation of ~4 cm ground sampling distance imagery along similar transects. Estimates of cover were similar between field-based and image-interpreted methods in 2009 and 2010 for woody vegetation, no vegetation, herbaceous vegetation, and litter (including woody litter). Image-interpretation slightly overestimated cover for woody vegetation and no-vegetation classes (average difference between methods of 1.34% and 5.85%) and tended to underestimate cover for herbaceous vegetation and litter (average difference of -5.18% and 0.27%), but the differences were significant only for litter cover in 2009. Level of agreement between the field-measurements and image-interpretation was good for woody vegetation and no-vegetation classes (r between 0.47 and 0.89), but generally poorer for herbaceous vegetation and litter (r between 0.18 and 0.81) likely due to differences in image quality by year and the difficulty in discriminating fine vegetation and litter in imagery. Our results show that image interpretation to detect vegetation changes has utility for monitoring fuels reduction treatments in terms of woody vegetation and no-vegetation classes. The benefits of this technique are that it provides objective and repeatable measurements of site conditions that could be implemented relatively inexpensively and easily without the need for highly specialized software or technical expertise. Perhaps the biggest limitations of image interpretation to monitoring fuels treatments are challenges in estimating litter and herbaceous vegetation cover and the sensitivity of herbaceous cover estimates to image quality and shadowing.

          Authors

          Karl, Jason W., Gillan, Jeffrey K., Barger, Nichole N., Herrick, Jeffrey E. and Duniway, Michael C.

          Year Published

          2014

          Publication

          Ecological Indicators

          Locations
          DOI

          10.1016/j.ecolind.2014.05.0017

          Recent Articles

          Spatial Patterns of Grassland-Shrubland State Transitions: a 74 Year Record on Grazed and Protected Areas

          by Browning, Dawn, Franklin, Janet, Archer, Steven R., Gillan, Jeffrey K. and Guertin, D.Phillip

          Tree and shrub abundance has increased in many grasslands, causing changes in ecosystem carbon and nitrogen pools that are related to patterns of woody plant distribution. However, with regard to spatial patterns, little is known about (i) how they develop; (ii) how they are influenced by grazing; or (iii) the extent to which intraspecific interactions dictate them. We addressed these questi...

          published 2014 in Ecological Applications

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          by Karl, Jason W., Gillan, Jeffrey K., Barger, Nichole N., Herrick, Jeffrey E. and Duniway, Michael

          The use of very high resolution (VHR; ground sampling distances &lt; ~5cm) aerial imagery to estimate site vegetation cover and to detect changes from management has been well documented. However, as the purpose of monitoring is to document change over time, the ability to detect changes from imagery at the same or better level of accuracy and precision as those measured in situ must be assesse...

          published 2014 in Ecological Indicators


          Interpretation of High-Resolution Imagery for Detecting Woodland Cover Composition Change After Fuels Reduction Treatments

          by Karl, Jason W., Gillan, Jeffrey K., Barger, Nichole N., Herrick, Jeffrey E. and Duniway, Michael C.

          The use of very high resolution (VHR; ground sampling distances &lt; ~5cm) aerial imagery to estimate site vegetation cover and to detect changes from management has been well documented. However, as the purpose of monitoring is to document change over time, the ability to detect changes from imagery at the same or better level of accuracy and precision as those measured in situ must be assesse...

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