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Jonathan M. Friedman

Publications and source records attributed to Jonathan M. Friedman.

At least 73 records · Page 4Linked to original sources
USGS2009

Influence of flow variability on floodplain formation and destruction, Little Missouri River, North Dakota

Resolving observations of channel change into separate planimetric measurements of floodplain formation and destruction reveals distinct relations between these processes and the flow regime. We analyzed a time sequence of eight bottomland images from 1939 to 2003 along the Little Missouri River, North Dakota, to relate geomorphic floodplain change to flow along this largely unregulated river. At the decadal scale, floodplain formation and destruction varied independently. Destruction was strongly positively correlated with the magnitude of infrequent high flows that recur every 5-10 yr, whereas floodplain formation was negatively correlated with the magnitude of frequent low flows exceeded 80% of the time. At the century scale, however, a climatically induced decrease in peak flows has reduced the destruction rate, limiting the area made available for floodplain formation. The rate of destruction was not uniform across the floodplain. Younger surfaces were consistently destroyed at a higher rate than older surfaces, suggesting that throughput of contaminants would have occurred more rapidly than predicted by models that assume uniform residence time of sediment across the floodplain. Maps of floodplain ages produced by analysis of sequential floodplain images are similar to maps of forest ages produced through dendrochronology, confirming the assumption of dendrogeomorphic studies that riparian tree establishment in this system is limited to recent channel locations. ?? 2009 Geological Society of America.

Geological Society of America Bulletin↗
USGS2008

Latitudinal variation in cold hardiness in introduced Tamarix and native Populus

To investigate the evolution of clinal variation in an invasive plant, we compared cold hardiness in the introduced saltcedar ( Tamarix ramosissima , Tamarix chinensis , and hybrids) and the native plains cottonwood ( Populus deltoides subsp. monilifera ). In a shadehouse in Colorado (41°N), we grew plants collected along a latitudinal gradient in the central United States (29–48°N). On 17 occasions between September 2005 and June 2006, we determined killing temperatures using freeze-induced electrolyte leakage and direct observation. In midwinter, cottonwood survived cooling to −70°C, while saltcedar was killed at −33 to −47°C. Frost sensitivity, therefore, may limit northward expansion of saltcedar in North America. Both species demonstrated inherited latitudinal variation in cold hardiness. For example, from September through January killing temperatures for saltcedar from 29.18°N were 5–21°C higher than those for saltcedar from 47.60°N, and on September 26 and October 11, killing temperatures for cottonwood from 33.06°N were >43°C higher than those for cottonwood from 47.60°N. Analysis of nine microsatellite loci showed that southern saltcedars are more closely related to T. chinensis while northern plants are more closely related to T. ramosissima . Hybridization may have introduced the genetic variability necessary for rapid evolution of the cline in saltcedar cold hardiness.

Evolutionary Applications↗
USGS2006

Transverse and longitudinal variation in woody riparian vegetation along a montane river

This study explores how the relationship between flow and riparian vegetation varies along a montane river. We mapped occurrence of woody riparian plant communities along 58 km of the San Miguel River in southwestern Colorado. We determined the recurrence interval of inundation for each plant community by combining step-backwater hydraulic modeling at 4 representative reaches with Log-Pearson analysis of 4 stream gaging stations. Finally, we mapped bottomland surficial geology and used a Geographic Information System to overlay the coverages of geology and vegetation. Plant communities were distinctly arrayed along the hydrologic gradient. The Salix exigua Nuttall (sand-bar willow) community occurred mostly on surfaces with a recurrence interval of inundation shorter than 2.2 years; the Betula occidentalis Hooker (river birch) community peaked on sites with recurrence intervals of inundation between 2.2 and 4.6 years. The hydrologic position occupied by communities dominated by Populus angustifolia James (narrowleaf cottonwood) was strongly related to age of trees and species composition of understory shrubs. The fraction of riparian vegetation on surfaces historically inundated by the river decreased in the upstream direction from almost 100% near Uravan to <50% along the South Fork of the San Miguel River. In upstream reaches much of the physical disturbance necessary to maintain riparian vegetation is provided by valley-side processes including debris flows, floods from minor tributaries, landslides, and beaver activity. Where valley-side processes are important, prediction of riparian vegetation change based on alterations of river flow will be incomplete.

Western North American Naturalist↗
USGS2005

Dating floodplain sediments using tree-ring response to burial

Floodplain sediments can be dated precisely based on the change in anatomy of tree rings upon burial. When a stem of tamarisk (Tamarix ramosissima) or sandbar willow (Salix exigua) is buried, subsequent annual rings in the buried section resemble the rings of roots: rings become narrower, vessels within the rings become larger, and transitions between rings become less distinct. We combined observations of these changes with tree-ring counts to determine the year of deposition of sedimentary beds exposed in a 150-m-long trench across the floodplain of the Rio Puerco, a rapidly filling arroyo in New Mexico. This method reliably dated most beds thicker than about 30 cm to within a year of deposition. Floodplain aggradation rates varied dramatically through time and space. Sediment deposition was mostly limited to brief overbank flows occurring every few years. The most rapid deposition occurred on channel-margin levees, which migrated laterally during channel narrowing. At the decadal timescale, the cross-section-average sediment deposition rate was steady, but there was a shift in the spatial pattern of deposition in the 1980s. From 1936 to 1986, sediment deposition occurred by channel narrowing, with little change in elevation of the thalweg. After 1986 sediment deposition occurred by vertical aggradation. From 1936 to 2000 about 27 per cent of the arroyo cross-section filled with sediment. The rate of filling from 1962 to 2000 was 0-8 vertical m/decade or 85 m2/decade. Published in 2005 by John Wiley & Sons, Ltd.

Earth Surface Processes and Landforms↗
USGS2005

Use of individualistic streamflow-vegetation relations along the Fremont River, Utah, USA to assess impacts of flow alteration on wetland and riparian area

We analyzed the transverse pattern of vegetation along a reach of the Fremont River in Capitol Reef National Park, Utah, USA using models that support both delineation of wetland extent and projection of the changes in wetland area resulting from upstream hydrologic alteration. We linked stage-discharge relations developed by a hydraulic model to a flow-duration curve derived from the flow history in order to calculate the inundation duration of 361 plots (0.5 × 2 m). Logistic regression was used to relate plant species occurrence in plots to inundation duration. A weighted average of the wetland indicator values of species was used to characterize plots as Aquatic, Wetland, Transitional, or Upland. Finally, we assessed how alterations in the flow duration curve would change the relative widths of these four zones. The wetland indicator values of species and the wetland prevalence index scores of plots were strongly correlated with inundation duration. Our results support the concept that plants classified as wetland species typically occur on sites inundated at least two weeks every two years. The portion of the riparian zone along the high-gradient study reach of the Fremont River that satisfied the vegetation criterion for a regulatory wetland was narrow (2 m wide). Both the unvegetated Aquatic zone (7.8 m) and the Transitional zone (8 m) were substantially wider. The Transitional zone included the maxima of several species and was, therefore, not merely a combination of elements of the Wetland and Upland zones. Multiplicative increases or decreases in streamflow regime produced a wetter, or drier, bottomland vegetation, respectively. Systematic reductions in flow variability reduced the width of both the Wetland and Transitional zones and increased the width of the Upland zone. Our approach is widely applicable to inform water management decisions involving changes in flow regime.

Wetlands↗
USGS2002

Potential responses of riparian vegetation to dam removal

Throughout the world, riparian habitats have been dramatically modified from their natural condition. Dams are one of the principal causes of these changes, because of their alteration of water and sediment regimes ( Nilsson and Berggren 2000 ). Because of the array of ecological goods and services provided by natural riparian ecosystems ( Naiman and Decamps 1997 ), their conservation and restoration have become the focus of many land and water managers. Efforts to restore riparian habitats and other riverine ecosystems have included the management of flow releases downstream of dams to more closely mimic natural flows ( Poff et al. 1997 ), but dam removal has received little attention as a possible approach to riparian restoration.

BioScience↗
USGS2002

Extreme floods, channel change, and riparian forests along ephemeral streams

The geomorphic effectiveness of extreme floods increases with aridity and decreasing watershed size. Therefore, in small dry watersheds extreme floods should control the age structure and spatial distribution of populations of disturbance-dependent riparian trees. We examined the influence of extreme floods on the bottomland morphology and forest of ephemeral streams in a semiarid region. Along six stream reaches on the Colorado Piedmont we examined channel changes by analyzing a rectified sequence of aerial photographs spanning 56 yr, and we investigated the spatial distribution of different-aged patches of forest by aging 189 randomly sampled cottonwood trees. Channel change in these ephemeral sand-bed streams is dominated by widening, which occurs over a span of hours during infrequent floods, and postflood narrowing, which occurs over decades between floods. Narrowing is accelerated where reliable moisture increases the density and growth rate of vegetation on the former bed. Reproduction of cottonwood trees has occurred mostly in former channel bed during periods of channel narrowing beginning after floods in 1935 and 1965 and continuing for as long as two decades. Thus cottonwood establishment is related to low flows at the time scale of a year, but to high flows at the time scale of decades. At sites that have not experienced major floods in the last 80 yr, little channel change has occurred, cottonwood reproduction has been limited, tree density has declined, and succession to grassland is occurring. Because channel change and tree reproduction in this region are driven by infrequent local events, channel width and tree age distributions vary greatly over time and among sites. For the same reason, riparian forests along these ephemeral streams can be as wide as forests along perennial rivers with much higher mean discharge.

Ecological Monographs↗
USGS2000

The disparity between extreme rainfall events and rare floods - with emphasis on the semi-arid American West

Research beginning 40 years ago suggested that semi-arid lands of the USA have higher unit discharges for a given recurrence interval than occur in other areas. Convincing documentation and arguments for this suspicion, however, were not presented. Thus, records of measured rainfall intensities for specified durations and recurrence intervals, and theoretical depths of probable maximum precipitation for specified recurrence intervals and areal scales are considered here for comparing extreme rainfalls of semi-arid areas with those of other climatic areas. Runoff from semi-arid lands, as peaks of rare floods, is compared with that of other areas using various published records. Relative to humid areas, semi-arid parts of the conterminous USA have lower 100-year, 6-h rainfall intensities and smaller depths of 100-year probable maximum precipitation for 26-km 2 areas. Nonetheless, maximum flood peaks, flash-flood potentials, and runoff potentials are generally larger in semi-arid areas than in more humid parts of the nation. Causes of this disparity between rainfall and runoff appear to be results of soil and vegetation that in humid areas absorb and intercept rainfall and attenuate runoff, but in semi-arid areas limit infiltration and enhance runoff from bare, crusted surfaces. These differences in soil and vegetation conditions are indicated by the relatively high curve numbers and drainage densities that are typical of semi-arid areas. Owing to soil and vegetation conditions, rare floods in semi-arid areas are more likely to cause landform change than are floods of similar magnitude elsewhere.

Hydrological Processes↗
USGS2000

High flow and riparian vegetation along the San Miguel River, Colorado

Riparian ecosystems are characterized by abundance of water and frequent flow related disturbance. River regulation typically decreases peak flows, reducing the amount of disturbance and altering the vegetation. The San Miguel River is one of the last relatively unregulated rivers remaining in the Colorado River Watershed. One goal of major landowners along the San Miguel including the Bureau of Land Management and The Nature Conservancy is to maintain their lands in a natural condition. Conservation of an entire river corridor requires an integrated understanding of the variability in ecosystems and external influences along the river. Therefore, the Bureau of Land Management and others have fostered a series of studies designed to catalogue that variability, and to characterize the processes that maintain the river as a whole. In addition to providing information useful to managers, these studies present a rare opportunity to investigate how a Colorado river operates in the absence of regulation.

Colorado↗
USGS2000

Floods, flood control, and bottomland vegetation

Bottomland plant communities are typically dominated by the effects of floods. Floods create the surfaces on which plants become established, transport seeds and nutrients, and remove establish plants. Floods provide a moisture subsidy that allows development of bottomland forests in arid regions and produce anoxic soils, which can control bottomland plant distribution in humid regions. Repeated flooding produces a mosaic of patches of different age, sediment texture, and inundation duration; this mosaic fosters high species richness.

Book chapter↗
USGS1998

Downstream effects of dams on channel geometry and bottomland vegetation: Regional patterns in the Great Plains

The response of rivers and riparian forests to upstream dams shows a regional pattern related to physiographic and climatic factors that influence channel geometry. We carried out a spatial analysis of the response of channel geometry to 35 dams in the Great Plains and Central Lowlands, USA. The principal response of a braided channel to an upstream dam is channel-narrowing, and the principal response of a meandering channel is a reduction in channel migration rate. Prior to water management, braided channels were most common in the southwestern Plains where sand is abundant, whereas meandering channels were most common in the northern and eastern Plains. The dominant response to upstream dams has been channel-narrowing in the southwestern Plains (e.g., six of nine cases in the High Plains) and reduction in migration rate in the north and east (e.g., all of twelve cases in the Missouri Plateau and Western Lake Regions). Channel-narrowing is associated with a burst of establishment of native and exotic woody riparian pioneer species on the former channel bed. In contrast, reduction in channel migration rate is associated with a decrease in reproduction of woody riparian pioneers. Thus, riparian pioneer forests along large rivers in the southwestern Plains have temporarily increased following dam construction while such forests in the north and east have decreased. These patterns explain apparent contradictions in conclusions of studies that focused on single rivers or small regions and provide a framework for predicting effects of dams on large rivers in the Great Plains and elsewhere. These conclusions are valid only for large rivers. A spatial analysis of channel width along 286 streams ranging in mean annual discharge from 0.004 to 1370 cubic meters per second did not produce the same clear regional pattern, in part because the channel geometries of small and large streams are affected differently by a sandy watershed.

Great Plains↗
USGS1997

Constraints on establishment of plains cottonwood in an urban riparian preserve

Plot sampling and hydraulic modeling were combined to investigate establishment and survival of plains cottonwood along Boulder Creek, an urban stream on the Colorado Plains. We tested the hypothesis that establishment is limited to bare, moist surfaces produced by spring flooding in the current year. No cottonwood germination was observed in 1989 when peak flow was low. A moderate peak of 11.9 m 3 /s in 1990 resulted in cottonwood establishment on surfaces inundated by discharges less than 15 m 3 /s. Surviving sapling cottonwoods established before 1989 occurred on surfaces inundated by discharges of 15–31 m 3 /s and dated to years with peak flows over 15 m 3 /s. Since 1969, establishment of cottonwood has been limited to a floodplain 21 m wide. Flow regulation and channel stabilization upstream and downstream of the study area have reduced the channel movement and overbank flooding that otherwise would have created bare, moist sites suitable for cottonwood establishment across a wider area. GIS analysis of aerial photographs shows that between 1937 and 1992 the channel has not moved and forest has encroached upon formerly open areas near the channel. A terrace, 317 m wide, is now dominated by trees that can reproduce in the absence of disturbance, especially the exotic crack willow.

Colorado↗
USGS1997

Flood dependency of cottonwood establishment along the Missouri River, Montana, USA

Flow variability plays a central role in structuring the physical environment of riverine ecosystems. However, natural variability in flows along many rivers has been modified by water management activities. We quantified the relationship between flow and establishment of the dominant tree (plains cottonwood, Populus deltoides subsp. monilifera ) along one of the least hydrologically altered alluvial reaches of the Missouri River: Coal Banks Landing to Landusky, Montana. Our purpose was to refine our understanding of how local fluvial geomorphic processes condition the relationship between flow regime and cottonwood recruitment. We determined date and elevation of tree establishment and related this information to historical peak stage and discharge over a 112-yr hydrologic record. Of the excavated trees, 72% were established in the year of a flow >1400 m 3 /s (recurrence interval of 9.3 yr) or in the following 2 yr. Flows of this magnitude or greater create the necessary bare, moist establishment sites at an elevation high enough to allow cottonwoods to survive subsequent floods and ice jams. Almost all cottonwoods that have survived the most recent flood (1978) were established >1.2 m above the lower limit of perennial vegetation (active channel shelf). Most younger individuals were established between 0 and 1.2 m, and are unlikely to survive over the long term. Protection of riparian cottonwood forest along this National Wild and Scenic section of the Missouri River depends upon maintaining the historical magnitude, frequency, and duration of floods >1400 m 3 /s. Here, a relatively narrow valley constrains lateral channel movement that could otherwise facilitate cottonwood recruitment at lower flows. Effective management of flows to promote or maintain cottonwood recruitment requires an understanding of locally dominant fluvial geomorphic processes.

Montana↗
USGS1994

Establishment, sex structure and breeding system of an exotic riparian willow, Salix X rubens

Several Eurasian tree willows ( Salix spp.) have become naturalized in riparian areas outside of their native range. Salix x rubens is a Eurasian willow that is conspicuous along streams in the high plains of Colorado. We examined establishment of seedlings and cuttings, the sex structure and the breeding system of S. x rubens . An experiment was conducted on establishment and growth of seedlings and cuttings under a range of hydrologic conditions. Seedlings became established under all conditions except when flooded, although many fewer seedlings became established where soil surface conditions were relatively dry. Cuttings became established under all experimental conditions, but most frequently where soil moisture was highest. The sex structure of S. x rubens was determined along several streams in the Colorado high plains. Of 2175 trees surveyed, >99% (2172) were female. Salix x rubens produce viable seed apparently as a result of hybridization with another Eurasian willow, S. alba var. vitellina . Salix x rubens often reproduces vegetatively, which, combined with low hybrid seedling survival in the field, may explain the unusual sex structure. Salix x rubens will likely continue to spread vegetatively in high plains riparian areas, and the potential for spread through hybridization could increase if males of compatible Salix spp. are planted near extant S. x rubens .

American Midland Naturalist↗