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Articles 1 - 15 of 15

Full-Text Articles in Physical Sciences and Mathematics

Proceedings Of A Workshop On American Eel Passage Technologies, Alex Haro Jul 2013

Proceedings Of A Workshop On American Eel Passage Technologies, Alex Haro

Alexander Haro

No abstract provided.


Use Of Landscape-Based And Intensive Field Assessments For Development And Use Of Wetland Indices Of Biological Integrity, Scott D. Jackson Mar 2012

Use Of Landscape-Based And Intensive Field Assessments For Development And Use Of Wetland Indices Of Biological Integrity, Scott D. Jackson

Scott D. Jackson

No abstract provided.


Global Change, Global Trade, And The Next Wave Of Plant Invasions, Bethany Bradley, D. M. Blumenthal, R. Early, E. D. Grosholz, J. J. Lawler, L. P. Miller, C. J.B Sorte, C. M. D'Antonio, J. M. Diez, J. S. Dukes, I. Ibanez, J. D. Olden Jan 2012

Global Change, Global Trade, And The Next Wave Of Plant Invasions, Bethany Bradley, D. M. Blumenthal, R. Early, E. D. Grosholz, J. J. Lawler, L. P. Miller, C. J.B Sorte, C. M. D'Antonio, J. M. Diez, J. S. Dukes, I. Ibanez, J. D. Olden

Bethany Bradley

Many non-native plants in the US have become problematic invaders of native and managed ecosystems, but a new generation of invasive species may be at our doorstep. Here, we review trends in the horticultural trade and invasion patterns of previously introduced species and show that novel species introductions from emerging horticultural trade partners are likely to rapidly increase invasion risk. At the same time, climate change and water restrictions are increasing demand for new types of species adapted to warm and dry environments. This confluence of forces could expose the US to a range of new invasive species, including many …


Massachusetts River And Stream Crossing Standards, Scott D. Jackson, Alison Bowden, Beth Lambert, Amy Singler Mar 2011

Massachusetts River And Stream Crossing Standards, Scott D. Jackson, Alison Bowden, Beth Lambert, Amy Singler

Scott D. Jackson

No abstract provided.


Evaluation Of A Rapid Assessment Protocol To Assess Road-Stream Crossings For Aquatic Organism Passage, Scott D. Jackson, Denis Luken Jan 2010

Evaluation Of A Rapid Assessment Protocol To Assess Road-Stream Crossings For Aquatic Organism Passage, Scott D. Jackson, Denis Luken

Scott D. Jackson

The River and Stream Continuity Partnership has developed assessment protocols for evaluating the barrier effects of road-stream crossings. In addition to these protocols, the University of Massachusetts Amherst created an online database and an algorithm for scoring crossing structures according to the degree of obstruction they pose to aquatic organisms. In 2008, The Nature Conservancy and University of Massachusetts collected data to test the robustness and repeatability of the protocol and compare results with those of other fish passage models. A stratified random sample of 317 road stream crossings in Connecticut, Vermont, New Hampshire and Massachusetts that had previously been …


Stream Simulation: An Ecological Approach To Providing Passage For Aquatic Organisms At Road-Stream Crossings Aug 2008

Stream Simulation: An Ecological Approach To Providing Passage For Aquatic Organisms At Road-Stream Crossings

Scott D. Jackson

No abstract provided.


Utilizing A Multi-Technique, Multi-Taxa Approach To Monitoring Wildlife Passageways On The Bennington Bypass In Southern Vermont, Mark A. Bellis, Scott D. Jackson, Curtis R. Griffin, Paige S. Warren, Alan O. Thompson May 2007

Utilizing A Multi-Technique, Multi-Taxa Approach To Monitoring Wildlife Passageways On The Bennington Bypass In Southern Vermont, Mark A. Bellis, Scott D. Jackson, Curtis R. Griffin, Paige S. Warren, Alan O. Thompson

Scott D. Jackson

Roadways affect wildlife habitat disproportionate to the area of land they occupy while impacting wildlife directly through direct loss of habitat, road mortality and disruption of movement. Roadways indirectly impact wildlife by isolating populations and disrupting gene flow and metapopulation dynamics. A variety of strategies have been used with mixed success to mitigate the impacts of transportation systems on wildlife. Underpasses are commonly used to facilitate movement of wildlife across roadways in Europe, Australia, Canada and the U.S. Through 2005, 460 terrestrial and 300 aquatic crossing structures have been identified throughout the United States but only a small portion of …


Characterizing The Landscape Dynamics Of An Invasive Plant And Risk Of Invasion Using Remote Sensing, Bethany Bradley, J. F. Mustard Jan 2005

Characterizing The Landscape Dynamics Of An Invasive Plant And Risk Of Invasion Using Remote Sensing, Bethany Bradley, J. F. Mustard

Bethany Bradley

Improved understanding of the spatial dynamics of invasive plant species may lead to more effective land management and reduced future invasion. Here, we identified the spatial extents of nonnative cheatgrass (Bromus tectorum) in the north central Great Basin using remotely sensed data from Landsat MSS, TM, and ETM+. We compared cheatgrass extents in 1973 and 2001 to six spatially explicit landscape variables: elevation, aspect, hydrographic channels, cultivation, roads, and power lines. In 2001, Cheatgrass was 10% more likely to be found in elevation ranges from 1400 to 1700 m (although the data suggest a preferential invasion into lower elevations by …


Ecological Considerations In The Design Of River And Stream Crossings, Scott D. Jackson Jan 2003

Ecological Considerations In The Design Of River And Stream Crossings, Scott D. Jackson

Scott D. Jackson

As long linear ecosystems, rivers and streams are particularly vulnerable to fragmentation. There is growing concern about the role of road crossings – and especially culverts – in altering habitats and disrupting river and stream continuity. Most of the culverts currently in place were designed with the principal objective of moving water across a road alignment. Little consideration was given to ecosystem processes such as the natural hydrology, sediment transport, fish and wildlife passage, or the movement of woody debris. It is not surprising then that many culverts significantly disrupt the movement of aquatic organisms. Survival of individual animals, facilitation …


Medusae Fossae Formation: New Perspectives From Mars Global Surveyor, Bethany Bradley, S. E.H Sakimoto, H. Frey, J. R. Zimbelman Aug 2002

Medusae Fossae Formation: New Perspectives From Mars Global Surveyor, Bethany Bradley, S. E.H Sakimoto, H. Frey, J. R. Zimbelman

Bethany Bradley

The nature and origin of the Medusae Fossae Formation (MFF) on Mars has been debated since the return of the first Viking images. The MFF's young age, distinctive surface texture, and lack of obvious source have prompted multiple hypotheses for its origin. This study uses data from the Mars Global Surveyor (MGS) mission to examine the MFF at all available scales. We discuss and quantify observations from Mars Orbiter Laser Altimeter (MOLA) topography and Mars Orbiter Camera (MOC) images to better constrain the origin of the MFF. Topographic grid estimates yield a present extent of 2.1 × 106 km2 and …


Overview Of Transportation Impacts On Wildlife Movement And Populations, Scott D. Jackson Jan 2000

Overview Of Transportation Impacts On Wildlife Movement And Populations, Scott D. Jackson

Scott D. Jackson

As long linear features on the landscape, railways, roads and highways have impacts on wildlife and wildlife habitat that are disproportionate to the area of land that they occupy. In addition to impacts on habitat, highways and railways are sources of road mortality that threaten wildlife populations. Indirect effects on wildlife include reduced access to habitat due to road avoidance and human exploitation. Transportation infrastructure also undermines ecological processes through the fragmentation of wildlife populations, restriction of wildlife movements, and the disruption of gene flow and metapopulation dynamics. A variety of techniques have been used to mitigate the impacts of …


A Strategy For Mitigating Highway Impacts On Wildlife, Scott D. Jackson, C. R. Griffin Jan 2000

A Strategy For Mitigating Highway Impacts On Wildlife, Scott D. Jackson, C. R. Griffin

Scott D. Jackson

Animal passage systems can be designed to facilitate movement of certain wildlife species across highways. Where the conservation of a particular species or group of species is concerned, specifically designed mitigation has proven successful for a number of species. However, the effectiveness of highway mitigation systems has not been evaluated with respect to the vast majority of wildlife. It is probable that some species do not require specific design features while others will require careful attention to factors such as placement, size, substrate, noise, temperature, light and moisture. In areas where road and highway density is high, conservation of particular …


Behavior And Passage Of Silver-Phase American Eels, Anguilla Rostrata (Lesueur), At A Small Hydroelectric Facility, Alex Haro, Ted Castro-Santos, Jacques Boubee Jan 2000

Behavior And Passage Of Silver-Phase American Eels, Anguilla Rostrata (Lesueur), At A Small Hydroelectric Facility, Alex Haro, Ted Castro-Santos, Jacques Boubee

Alexander Haro

Downstream migrant eels were monitored near a small (51 MW) hydroelectric facility on the Connecticut River (Massachusetts, USA) for two seasons using acoustic and radio telemetry. Eels frequently made several attempts over periods of one to several days to pass the station. Diel activity of eels was variable, although most movements occurred at night. Eels occupied a variety of depths in the forebay area, but spent the greater proportion of time at or near the bottom (10 m), occasionally venturing to the surface. Horizontal movements usually spanned across the entire width of the forebay. There was no significant relationship between …


Underpass Systems For Amphibians, Scott D. Jackson Jan 1996

Underpass Systems For Amphibians, Scott D. Jackson

Scott D. Jackson

No abstract provided.


Effectiveness Of Drift Fences And Tunnels For Moving Spotted Salamanders Ambystoma Maculatum Under Roads, Scott D. Jackson, T. F. Tyning Jan 1989

Effectiveness Of Drift Fences And Tunnels For Moving Spotted Salamanders Ambystoma Maculatum Under Roads, Scott D. Jackson, T. F. Tyning

Scott D. Jackson

No abstract provided.