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Beavers (Castor canadensis Kuhl) can influence the competitive dynamics of plant species through selective foraging, collection of materials for dam creation, and alteration of hydrologic conditions. In the Grand Canyon National Park, the native Salix gooddingii C.R.Ball (Goodding?s willow) and Salix exigua Nutt. (coyote willow) are a staple food of beavers. Because Salix competes with the invasive Tamarix ramosissima Ledeb., land mangers are concerned that beavers may cause an increase in Tamarix through selective foraging of Salix. A spatial analysis was conducted to assess whether the presence of beavers correlates with the relative abundance of Salix and Tamarix. These methods were designed to detect a system-wide...
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As part of a study to investigate the causes of channel narrowing and incision in Canyon de Chelly National Monument, the effects of Tamarisk and Russian-olive on streambank stability were investigated. In this study, root tensile strengths and distributions in streambanks were measured and used in combination with a root-reinforcement model, RipRoot, to estimate the additional cohesion provided to layers of each streambank. The additional cohesion provided by the roots in each 0.1-m layer ranged from 0 to 6.9 kPa for Tamarisk and from 0 to 14.2 kPa for Russian-olive. Average root-reinforcement values over the entire bank profile were 2.5 and 3.2 kPa for Tamarisk and Russian-olive, respectively. The implications...
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The 1935 images were obtained as digitally scanned versions of aerial photographs acquired by the U.S. Department of Agriculture at a scale of 1:31,680. The actual date of image acquisition is not known. The images were previously scanned at 600 dpi to produce a nominal pixel size of 1.28 m (Friedman et al., 2015). The images were registered and rectified using identifiable common points from the 1996 DOQQs. See description of positional accuracy below. Data derived from features mapped from the 1935 images were presented in: Friedman, J.M., Vincent, K.R., Griffin, E.R., Scott, M.L., Shafroth, P.B., and Auble, G.T., 2015, Processes of arroyo filling in northern New Mexico, USA, GSA Bulletin, 127(3/4), 621-640....
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These data consist of species relative cover, percent cover of dead plant material, percent cover of soil and rock, and a variety of broad - and local- scale environmental variables. These data relate to sample sites along the Colorado River through Grand Canyon between Lees Ferry and river mile 245. The plant and ground cover data included here were originally collected as a part of annual vegetation monitoring by Grand Canyon Monitoring and Research Center. Environmental variables were either recorded in the field or obtained through other data sources. Species and ground cover data were collected in August and September 2014 at 96 randomly selected sample sites that were approximately evenly distributed along...
Biological invasions are a threat to ecosystems across all biogeographical realms. Riparian habitats are considered to be particularly prone to invasion by alien plant species and, because riparian vegetation plays a key role in both aquatic and terrestrial ecosystems, research in this field has increased. Most studies have focused on the biology and autecology of invasive species and biogeographical aspects of their spread. However, given that hydrogeomorphological processes greatly influence the structure of riparian plant communities, and that these communities in turn affect hydrology and fluvial geomorphology, scant attention has been paid to the interactions between invasions and these physical processes....
As global climate change affects recharge and runoff processes, stream flow regimes are being altered. In the American Southwest, increasing aridity is predicted to cause declines in stream base flows and water tables. Another potential outcome of climate change is increased flood intensity. Changes in these stream flow conditions may independently affect vegetation or may have synergistic effects. Our goal was to extrapolate vegetation response to climate-linked stream flow changes, by taking advantage of the spatial variation in flow conditions over a 200 km length of the San Pedro River (Arizona). Riparian vegetation traits were contrasted between sites differing in low-flow hydrology (degree of stream intermittency)...
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The 1970s images were obtained as digital scans on CDs, with no metadata. Source information for the original aerial photographs is not available. Original photo scale was about 1:40,000 for the 1975 images (filenames beginning "r75")and 1:12,000 for the 1979 images (filenames beginning "rfl"). I registered and rectified these images using identifiable common points from 1996 DOQQs. See the description of positional accuracy below. Data derived from features mapped from the 1970s images were presented in: Friedman, J.M., Vincent, K.R., Griffin, E.R., Scott, M.L., Shafroth, P.B., and Auble, G.T., 2015, Processes of arroyo filling in northern New Mexico, USA, GSA Bulletin, 127(3/4), 621-640. doi: 10.1130/B31046.1
1. Riparian vegetation in dry regions is influenced by low-flow and high-flow components of the surface and groundwater flow regimes. The duration of no-flow periods in the surface stream controls vegetation structure along the low-flow channel, while depth, magnitude and rate of groundwater decline influence phreatophytic vegetation in the floodplain. Flood flows influence vegetation along channels and floodplains by increasing water availability and by creating ecosystem disturbance. 2. On reference rivers in Arizona's Sonoran Desert region, the combination of perennial stream flows, shallow groundwater in the riparian (stream) aquifer, and frequent flooding results in high plant species diversity and landscape...
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Riparian ecosystems are important components of landscapes, particularly because of their role in biodiversity. A first step in using a ""coarse-filter"" approach to riparian biodiversity conservation is to determine the kinds of riparian ecosystems. These ecosystems vary substantially in plant species composition along a single river reach, as well as between rivers, and yet the river-reach scale has received little attention. We sampled the vascular plant composition of 67 contiguous patches of riparian vegetation along the reach of the Animas River, in southwestern Colorado's San Juan Mountains, that is relatively undisturbed by human land uses. Using cluster analysis and detrended correspondence analysis, we...
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The intense demand for river water in arid regions is resulting in widespread changes in riparian vegetation. We present a direct gradient method to predict the vegetation change resulting from a proposed upstream dam or diversion. Our method begins with the definition of vegetative cover types, based on a census of the existing vegetation in a set of 1 x 2 m plots. A hydraulic model determines the discharge necessary to inundate each plot. We use the hydrologic record, as defined by a flow duration curve, to determine the inundation duration for each plot. This allows us to position cover types along a gradient of inundation duration. A change in river management results in a new flow duration curve, which is used...
The southwestern willow flycatcher (SWFL; Empidonax traillii extimus) is an endangered songbird whose habitat has declined dramatically over the last century. Understanding habitat selection patterns and the ability to identify potential breeding areas for the SWFL is crucial to the management and conservation of this species. We developed a multiscaled model of SWFL breeding habitat with a Geographic Information System (GIS), survey data, GIS variables, and multiple logistic regressions. We obtained presence and absence survey data from a riverine ecosystem and a reservoir delta in south-central Arizona, USA, in 1999. We extracted the GIS variables from satellite imagery and digital elevation models to characterize...
Riverine riparian vegetation has changed throughout the southwestern United States, prompting concern about losses of habitat and biodiversity. Woody riparian vegetation grows in a variety of geomorphic settings ranging from bedrock-lined channels to perennial streams crossing deep alluvium and is dependent on interaction between ground-water and surface-water resources. Historically, few reaches in Arizona, southern Utah, or eastern California below 1530 m elevation had closed gallery forests of cottonwood and willow; instead, many alluvial reaches that now support riparian gallery forests once had marshy grasslands and most bedrock canyons were essentially barren. Repeat photography using more than 3000 historical...
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1996 georeferenced aerial photographs cover the lower Rio Puerco from the confluence with the Rio San Jose 70 km down-valley to the confluence with the Rio Grande. The images were obtained from enlargements of 1:40,000 scale National Aerial Photography Program (NAPP) photographs printed from negatives at a scale of 1:5,000, then scanned at 600 dpi. Pixel size of the raster images is about 0.22 m, compared to the DOQQs, which have 1-m pixel size. The segments were registered and rectified in ArcINFO using common points from USGS DOQQs published in 1999, which were derived from the same 1996 NAPP photo set, with terrain corrections from a 1-degree DEM applied. Registration points were typically center of mass of small...
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High-precision (Real-time kinematic) Global Positioning System (GPS) surveys were conducted along the lower Rio Puerco in April 2002, January 2007, April 2010, and April 2014 to support a long-term study of geomorphic processes and the geomorphic history of the arroyo. The study reach extends from the confluence with the Rio San Jose 67 km downvalley to the old Highway 85 bridge near the USGS streamgage near Bernardo, NM. Individual shapefiles were created for data from each survey. Associated metadata files include the names of surveyors and equipment used. The survey extents varied, but all have overlapping points, including repeat surveys of arroyo cross sections. Results from analyses of these data were published...
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The 1950s images were downloaded from Earth Explorer as medium-resolution scans of aerial photographs, with pixel size ranging from 1.33 to 2.32 m. Original photo scales were 1:54,000 or 1:20,000. (See Source Citation below.) I registered and rectified these images using identifiable common points from 1996 DOQQs. Images with filenames beginning "r37" were acquired 11-29-1953. Images with filenames beginning "r43" were acquired 01-31-1954. Image r1954r49_6786.tif was acquired 02-03-1954. Remaining images have the date of acquisition in the filename, starting with the format "ryymmdd...". Data derived from features mapped from the 1950s images were presented in: Friedman, J.M., Vincent, K.R., Griffin, E.R., Scott,...
Empirical evidence from a semiarid watershed of the southwestern United States (Verde River basin, Arizona) indicated that abundance and species richness of mixed deciduous riparian forests varied in a curvilinear and quantifiable fashion as a function of stream flow parameters. Three indicators of riparian abundance?foliage area, stem basal area and stand width?increased most significantly with growing season flow volume, a surrogate indicator of riparian water availability. Tree species richness varied in a bell curve fashion with flood size, with the greatest richness occurring at streams with intermediate flood magnitudes. These instream flow models have management implications for riparian habitats. They suggest...
Floodplain plant-herbivore-hydroperiod interactions have received little attention despite their potential as determinants of floodplain structure and functioning. We used five types of exclosures to differentially exclude small-, medium-, and large-sized mammals from accessing Fremont cottonwood (Populus deltoides Marshall subsp. wizlizenii (Watson) Eckenwalder) seedlings and saplings growing naturally on four landform types at an alluvial reach on each of two rivers, the Green and Yampa, in Colorado and Utah. The two study reaches differed primarily as a result of flow regulation on the Green River, which began in 1962. Landforms were a rarely flooded portion of the alluvial plain, geomorphically active slow-...
Aim A regional analysis was used to explore the influence of river regulation on the dominance of non-native, invasive shrubs and trees. We addressed the following questions: (1) How do large dams affect hydrological parameters that influence riparian vegetation? (2) How do flow regimes affect the dominance of non-native woody species? (3) How do changes in flow regimes affect the dominance of non-native woody species? Location South-western USA. Methods We sampled the canopy cover of woody species on 179 point bars along seven non-dammed and thirteen dammed river segments. Wilcoxon rank sum tests were used to determine differences between flow parameters in dammed and non-dammed rivers. We used correlation analyses...
Previous studies of vegetation establishment in dam removal sites have shown that natural vegetation community establishment is highly variable and frequently includes species often considered undesirable in restorations. In this article, we examined two case studies where dam removal sites were planted with native species following dam removal in an effort to promote native species establishment and exclude invasive species. Some planted species established soon after the dam removals, but surveys four years later showed a decline in planted species and an increase in non-native species. In both cases, reed canarygrass (Phalaris arundinacea) became well established in the interval between surveys. A seedbank analysis...
map background search result map search result map Destabilization of streambanks by removal of invasive species in Canyon de Chelly National Monument, Arizona Relating Riparian Vegetation to Present and Future Streamflows Classification of the riparian vegetation along a 6-km reach of the Animas River, southwestern Colorado Lower Rio Puerco GPS survey data collected in 2002, 2007, 2010, and 2014 Lower Rio Puerco 1935 georeferenced aerial photographs Lower Rio Puerco 1950s georeferenced aerial photographs Lower Rio Puerco 1970s georeferenced aerial photographs Lower Rio Puerco 1996 georeferenced NAPP photo segments Riparian Vegetation and Environmental Variables, Colorado River, 2014—Data Classification of the riparian vegetation along a 6-km reach of the Animas River, southwestern Colorado Relating Riparian Vegetation to Present and Future Streamflows Lower Rio Puerco 1970s georeferenced aerial photographs Lower Rio Puerco 1935 georeferenced aerial photographs Lower Rio Puerco GPS survey data collected in 2002, 2007, 2010, and 2014 Lower Rio Puerco 1950s georeferenced aerial photographs Lower Rio Puerco 1996 georeferenced NAPP photo segments Destabilization of streambanks by removal of invasive species in Canyon de Chelly National Monument, Arizona Riparian Vegetation and Environmental Variables, Colorado River, 2014—Data