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Noelle G. Beckman - One of the best experts on this subject based on the ideXlab platform.

  • Forest Roads as partial barriers to terrestrial salamander movement
    Conservation Biology, 2005
    Co-Authors: David M. Marsh, Graham S Milam, Nicholas P Gorham, Noelle G. Beckman
    Abstract:

    : Roads can fragment animal populations by disrupting movement among formerly continuous habitats. Although models have demonstrated that disrupted movement can contribute to long-term extinction, there are few empirical data on the effects of Roads on animal movement. We used displacement and homing experiments to determine whether Forest Roads are barriers to the movement of terrestrial salamanders. We displaced 1471 red-backed salamanders (Plethodon cinereus) across five Forest Roads and compared return rates to those of salamanders displaced equal distances toward the Forest interior. Roads significantly reduced the return rate of salamanders, with a mean reduction of 51%. Steep Roadside verges further reduced return rates, particularly for salamanders moving downhill across verges. The permeability of Roads to salamander movement did not appear to be related to road surface type. Gravel Roads had both the highest and lowest observed permeability with the two paved Roads intermediate between these. We conclude that narrow Forest Roads are partial barriers to salamander movement and that steep Roadside verges may exacerbate these effects. Resumen: Las carreteras pueden fragmentar a las poblaciones animales al interrumpir el movimiento entre habitats anteriormente continuos. Aunque los modelos han demostrado que la interrupcion de movimiento puede contribuir a la extincion en el largo plazo, existen pocos datos empiricos sobre los efectos de carreteras sobre el movimiento de animales. Utilizamos experimentos de desplazamiento y de orientacion para determinar si las carreteras en bosques son barreras para el movimiento de salamandras terrestres. Desplazamos a 1471 individuos de Plethodon cinereus a traves de cinco carreteras y comparamos sus tasas de retorno con las de salamandras que fueron desplazadas a distancias equivalentes hacia el interior del bosque. Las carreteras aparentemente redujeron la tasa de retorno de salamandras, con una reduccion media de 51%. Los bordes de carretera empinados redujeron aun mas las tasas de retorno, particularmente para salamandras atravesando bordes cuesta abajo. La permeabilidad de las carreteras al movimiento de salamandras no parecio estar relacionado con el tipo de superficie de la carretera. Las carreteras cubiertas con grava tuvieron tanto la permeabilidad mas alta como la mas baja y las dos carreteras pavimentadas fueron intermedias entre las cubiertas con grava. Concluimos que las carreteras angostas son barreras parciales para el movimiento de salamandras y los bordes de carretera empinados pueden exacerbar estos efectos.

  • EFFECTS OF Forest Roads ON THE ABUNDANCE AND ACTIVITY OF TERRESTRIAL SALAMANDERS
    Ecological Applications, 2004
    Co-Authors: David M. Marsh, Noelle G. Beckman
    Abstract:

    One of the major effects of deForestation is the creation of numerous edge zones where remaining Forest meets nonForest habitat. At this interface, edge effects on Forest habitats can include altered abiotic conditions, changes in rates of competition and predation, and altered community structure. While the edge effects resulting from clear- cuts and other open habitats are well-studied, little is known about the comparative edge effects of Forest Roads. We studied the effects of Forest Roads on the abundance, surface activity, and body condition of red-backed salamanders (Plethodon cinereus) and slimy salamanders (P. glutinosus and P. cylindraceus) in the Southern Appalachians of Virginia. We conducted surveys for salamanders at 21 sites where gravel Roads bisected mature Forest. These sites were divided into three data sets based on region and year of survey. We also carried out an enclosure experiment to determine whether road edges influenced the surface activity and detectability of red-backed salamanders. We found fewer red-backed salaman- ders near Roads in all three data sets. These edge effects extended ,20 m into the Forest in two of the three data sets but increased linearly out to 80 m in the data set collected during an unusually dry period. In contrast, slimy salamanders showed no clear responses to Forest-road edges and had significantly different responses than those of red-backed salamanders. Within our experimental enclosures, red-backed salamander detectability did not differ between edge and interior habitats, suggesting that the patterns we observed were not simply due to changes in salamander activity patterns. Like red-backed salamander counts, soil moisture and cover object area also tended to decrease near Roads. The steepness of the gradient in soil moisture was a significant predictor of the steepness of the decline in salamander counts, while there was no significant relationship between the decreases in cover object area and decreases in salamander counts. Collectively, these results show that edge effects from Forest Roads may be comparable to edge effects from clear-cuts or other types of silvicultural edges. Additionally, they suggest that, for terrestrial salamanders, variation in the magnitude of edge effects may be related to variation in soil moisture. Management approaches that minimize soil desiccation associated with road building and maintenance may reduce the impacts of Roads on amphibian populations in adjacent Forest.

Charles H. Luce - One of the best experts on this subject based on the ideXlab platform.

  • linkages between unpaved Forest Roads and streambed sediment why context matters in directing road restoration
    Restoration Ecology, 2016
    Co-Authors: Robert Alchokhachy, Charles H. Luce, Thomas A Black, Cameron Thomas, Bruce E Rieman, Richard M Cissel, Anne Carlson, Shane Hendrickson, Eric Archer, Jeffrey L Kershner
    Abstract:

    Unpaved Forest Roads remain a pervasive disturbance on public lands and mitigating sediment from road networks remains a priority for management agencies. Restoring roaded landscapes is becoming increasingly important for many native coldwater fishes that disproportionately rely on public lands for persistence. However, effectively targeting restoration opportunities requires a comprehensive understanding of the effects of Roads across different ecosystems. Here, we combine a review and a field study to evaluate the status of knowledge supporting the conceptual framework linking unpaved Forest Roads with streambed sediment. Through our review, we specifically focused on those studies linking measures of the density of Forest Roads or sediment delivery with empirical streambed sediment measures. Our field study provides an example of a targeted effort of linking spatially explicit estimates of sediment production with measures of streambed sediment. Surprisingly, our review uncovered few studies (n = 8) that empirically tested the conceptual framework linking unpaved Forest Roads and streambed sediment, and the results varied considerably. Field results generally supported the conceptual model that unpaved Forest Roads can control streambed sediment quality, but demonstrated high-spatial variability in the effects of Forest Roads on streambed sediment and the need to address hotspots of sediment sources. The importance of context in the effects of Forest Roads is apparent in both our review and field data, suggesting the need for in situ studies to avoid misdirected restoration actions.

  • spatial and temporal patterns in erosion from Forest Roads
    In: Wigmosta M. S.; Burges S. J. eds. Land use and watersheds: human influence on hydrology and geomorphology in urban and forest areas. Water science, 2013
    Co-Authors: Charles H. Luce, Thomas A Black
    Abstract:

    Erosion from Forest Roads is an important contribution to the sediment budget of many Forested basins, particularly over short time scales. Sediment production from 74 road segments was measured over three years to examine how road slope, segment length, cutslope height, and soil texture affect sediment production and how these relationships change with time. In the first year, differences in sediment production between plots could be explained by differences in sediment transport capacity of the plots. With time, differences between plots of different slope, length, cutslope height, and soil were reduced as all plots produced less and less sediment. Recovery was rapid with around 70% recovery between by the second year and 90% recovery by the third year.

  • introduction to special issue on hydrologic and geomorphic effects of Forest Roads
    Earth Surface Processes and Landforms, 2001
    Co-Authors: Charles H. Luce, Beverley C. Wemple
    Abstract:

    Roads have been a part of human landscapes for more than 40 centuries. During the 20th century, technological advances have increased our ability to construct new Roads at unprecedented rates and into steeper terrain. In the last half of that century, an extensive network of Roads has been constructed in Forests and other wildlands to facilitate use and management of natural resources. They are the transportation system that allows transport of timber and minerals from Forests and access for recreationists, land managers, fire fighters, and residents of villages or vacation homes. Unfortunately, Forest road construction may result in adverse changes to the environment. Roads fragment terrestrial and aquatic ecosystems by acting as a barrier to movement of some animals and plants. Roads can act as transportation corridors for plants, animals and fungi, some desirable, some not. Roads also affect the movement of water and sediment through landscapes. The combination of effects can be detrimental to native terrestrial and aquatic organisms, and negative correlations between road density and fish stocks have been noted (Lee et al., 1997; Thompson and Lee, 2000). The linear nature of Roads and their tendency to run across topographic gradients yield an influence on watershed scale hydrologic processes that is much greater than one might expect from the small fraction of the land area they occupy. The concentration of runoff from nearly impervious road surfaces and intercepted subsurface flow into ditches effectively increases the drainage density, shifting the distribution of water on hillslopes and potentially increasing peak flows of streams. When there are few drainage features along Roads there can be substantial inter-basin transfers of water between first-order streams. The effect is exacerbated when stream crossing culverts are plugged by debris, diverting a stream to other places in the landscape such as other streams or previously unchannelled hillslopes. These hydrologic effects are partially responsible for changes to geomorphic processes and sediment budgets in roaded basins. Runoff from the road tread and intercepted subsurface flow contribute to surface erosion from soil bared by road construction, use and maintenance. Lateral concentration of water collected along the length of the road and discharged at ditch relief or stream crossing culverts increases the risk of landslides, gullies and destabilization of existing stream channels. Diversion of water from stream channels onto hillslopes or into other stream channels occurs more rarely but with greater consequence. The papers in this special issue address many of the hydrologic and geomorphic issues identified above and contain important advances in the fields of hydrology and geomorphology on the subjects of hydrologic modelling, surface erosion and landscape evolution. They examine how the flowpaths of water are altered by the presence of Roads and how these changes in flowpaths change geomorphic processes. Many of the efforts were spurred by recent work using digital elevation models (DEMs) to improve modelling of basin hydrology and landscape evolution. In a sense, Roads are an experiment on the landscape; by perturbing the topography, we can view changes in the spatial patterns in hydrologic and geomorphic processes caused by Roads, allowing us to test the principles derived in the earlier studies. Two papers primarily address hydrologic issues. They examine changes in flood frequency following road construction using distributed hydrologic models. Because stream flows are affected by both Roads and harvest areas, which are created within a short time of one another, it is difficult to derive statistically the independent effect of Roads and harvest from stream gauge data alone (Jones and Grant, 1996; Thomas and

  • sediment production from Forest Roads in western oregon
    Water Resources Research, 1999
    Co-Authors: Charles H. Luce, T A Black
    Abstract:

    Prevention and estimation of soil erosion from Forest Roads requires an understanding of how road design and maintenance affect sediment production. Seventy- four plots were installed on Forest Roads in the Oregon Coast Range to examine the relationship between sediment production and road attributes such as distance between culverts, road slope, soil texture, and cutslope height. An additional comparison was made between road segments with cutslopes and ditches freshly cleared of vegetation and segments with established vegetation on cutslopes and in ditches. All road segments were 5 m wide and insloped with aggregate surfacing, light traffic, and no overhanging Forest cover. Sediment production was correlated to the product of segment length times road slope squared. Sediment production from aggregate covered Roads on a silty clay loam was about 9 times greater than that from Roads constructed on a gravelly loam. Sediment production was not correlated to the cutslope height. Road segments where vegetation was cleared from the cutslope and ditch produced about 7 times as much sediment as road segments where vegetation was retained, showing the potential reduction in erosion by revegetation following construction and the potential impact of ditch cleaning during maintenance. Relationships and estimates from this study provide a basis for improved erosion estimates by commonly used empirical procedures.

  • effectiveness of road ripping in restoring infiltration capacity of Forest Roads
    Restoration Ecology, 1997
    Co-Authors: Charles H. Luce
    Abstract:

    Many Forest Roads are being closed as a step in watershed restoration. Ripping Roads with subsoilers or rock rippers is a common practice to increase the infiltration capacity of Roads before closure. When considering the effectiveness of ripping for reducing runoff and erosion and the potential reduction in slope stability by saturating road fills, it is important to know how ripping changes the infiltration capacity of Forest Roads. Hydrographs from simulated rainfall on 1 × 1 m plots were analyzed to find the saturated hydraulic conductivity, an indicator of infiltration capacity. I examined saturated hydraulic conductivity for three treatments on two different soils. One road was built in a soil derived from the metamorphic belt series geology of northern Idaho, a soil noted for its high rock fragment content. The second road was built in a sandy soil derived from decomposed granitics of the Idaho batholith. On each soil, five plots were installed on a road before ripping, and nine plots were installed on the same road segment following ripping, four covered with a heavy straw mulch and five without. Three half-hour rainfall events with intensities near 90 mm/hr were simulated on each plot. Results show that ripping increases hydraulic conductivities enough to reduce risk of runoff but does not restore the natural hydraulic conductivity of a Forested slope. The unripped road surfaces had hydraulic conductivities in the range of 0–4 mm/hr, whereas ripped Roads were in the range of 20–40 mm/hr after the second event. Surface sealing and tilled soil subsidence processes are important in reducing the hydraulic conductivity of the soils with repeated wetting. Subsidence appears to be important on the granitic soil, whereas surface sealing was more important on the belt series soil.

Philip J Noske - One of the best experts on this subject based on the ideXlab platform.

  • using rainfall simulation and site measurements to predict annual interrill erodibility and phosphorus generation rates from unsealed Forest Roads validation against in situ erosion measurements
    Catena, 2008
    Co-Authors: Gary J Sheridan, Philip J Noske, Patrick N J Lane, Christopher B Sherwin
    Abstract:

    Abstract The measurement of soil erosion rates under natural rainfall conditions is costly and time consuming. Data provided by rainfall simulation and static site measurements can be used to predict erosion rates under natural conditions, however the accuracy of this method is largely untested. This is especially true for erosion rates from unsealed Forest Roads. In this study, the values for a range of erodibility indices calculated from rainfall simulation experiments are compared to observed erodibility index values from 1 year of detailed in-situ erosion monitoring of seven different Forest road types. The prediction of phosphorus generation rates from rainfall simulation and/or soil sampling was also evaluated. The results showed that a series of commonly used erodibility indices such as sediment per unit rainfall, sediment per unit runoff, sediment per unit EI30, and sediment per unit rainfall energy were poorly predicted from the rainfall simulation experiments. Five of the six indices tested substantially overpredicted the observed erodibility at one site, a gravel road subjected to minimal traffic. For the other six road sites predictions were poor and highly variable, the coefficient of efficiency ranging from − 13.32 to 0.17 for these erodibility indices. A modified index, the ratio of sediment per unit rainfall energy to the mean rate of rainfall energy input, was able to predict annual erosion rates from six different road surfaces using rainfall simulation data with a coefficient of efficiency of 0.9. The results indicate that existing erodibility indices are not suitable for predicting observed erosion rates on Forest Roads using rainfall simulation data as collected in this study. It is argued that the modified index is more suited to sites (such as compacted Roads) where interrill processes dominate, and erosion rates are less sensitive to peak flows. With respect to nutrient generation rates, rainfall simulation was able to accurately predict the observed proportion by mass of total phosphorus (TP) in runoff with a coefficient of efficiency of 0.96. Direct soil sampling of the road surface could also be used to predict the proportion by mass of TP in runoff. Concentrations of total nitrogen in Forest road materials were found to be at the lower detection limit of the laboratory instruments.

  • catchment scale contribution of Forest Roads to stream exports of sediment phosphorus and nitrogen
    Hydrological Processes, 2007
    Co-Authors: Gary Sheridan, Philip J Noske
    Abstract:

    The relative contribution of Forest Roads to total catchment exports of suspended sediment, phosphorus, and nitrogen was estimated for a 13 451 ha Forested catchment in southeastern Australia. Instrumentation was installed for 1 year to quantify total in-stream exports of suspended sediment, phosphorus, and nitrogen. In addition, a total of 101 road–stream crossings were mapped and characterized in detail within the catchment to identify the properties of the road section where the road network and the stream network intersect. Sediment and nutrient generation rates from different Forest road types within the catchment were quantified using permanent instrumentation and rainfall simulation. Sediment and nutrient generation rates, mapped stream crossing information, traffic data and annual rainfall data were used to estimate annual loads of sediment, phosphorus, and nitrogen from each stream crossing in the catchment. The annual sum of these loads was compared with the measured total catchment exports to estimate the proportional contribution of loads from Roads within the catchment. The results indicated that 3·15 ha of near-stream unsealed road surface with an average slope of 8·4% delivered an estimated 50 t of the 1142 t of total suspended sediment exported from the catchment, or about 4·4% of the total sediment load from the Forest. Stream discharge over this period was 69 573 Ml. The unsealed road network delivered an estimated maximum of 22 kg of the 1244 kg of total phosphorus from the catchment, or less than 1·8% of the total load from the Forest. The average sediment and phosphorous load per crossing was estimated at 0·5 t (standard deviation 1·0 t) and 0·22 kg (standard deviation 0·30 kg) respectively. The lower proportional contribution of total phosphorus resulted from a low ratio of total phosphorus to total suspended sediment for the road-derived sediment. The unsealed road network delivered approximately 33 kg of the 20 163 kg of total nitrogen, about 0·16% of the total load of nitrogen from the Forest. The data indicate that, in this catchment, improvement of stream crossings would yield only small benefits in terms of net catchment exports of total suspended sediment and total phosphorus, and no benefit in terms of total nitrogen. These results are for a catchment with minimal road-related mass movement, and extrapolation of these findings to the broader Forested estate requires further research. Copyright © 2007 John Wiley & Sons, Ltd.

  • the effect of truck traffic and road water content on sediment delivery from unpaved Forest Roads
    Hydrological Processes, 2006
    Co-Authors: Gary Sheridan, Philip J Noske, Robyn K Whipp, Nimal Wijesinghe
    Abstract:

    A study investigated the effect of truck-traffic intensity and road water-content on the quality of runoff water from unsealed Forest Roads. Three sections of a gravel-surfaced Forest road were instrumented and exposed to low and high levels of truck traffic during wet winter conditions and dry summer conditions between July 2001 and December 2002. Rainfall, runoff, road moisture, and traffic were measured continuously, and suspended and bedload sediments were integrated measurements over 2-week site-service intervals. The median suspended sediment concentration from the three road segments under low truck-traffic conditions (less than nine return truck passes prior to a storm) was 269 mg l-1, increasing 2.7-fold to a median of 725 mg l-1 under high truck-traffic conditions (greater than or equal to nine return truck passes prior to a storm). These concentrations, and increases due to traffic, are substantially less than most previously reported values. When these data are expressed as modified universal soil loss equation (MUSLE) erodibility values K, accounting for differences in rainfall energy, site characteristics and runoff, high traffic resulted in a road surface that was four times more erodible than the same road under low traffic conditions. Using multiple regression, traffic explained 36% of the variation in MUSLE erodibility, whereas road water content was not significant in the model. There was little difference in the erodibility of the road when trafficked in low water-content compared with high water-content conditions (MUSLE K values of 0.0084 versus 0.0080 respectively). This study shows that, for a good quality well-maintained gravel Forest road, the level of truck traffic affects the sediment concentration of water discharging from the road, whereas the water content of the road at the time of that traffic does not (note that traffic is not allowed during runoff events in Victoria). These conclusions are conditional upon the road being adequately maintained so that trafficking does not compromise the lateral drainage of the road profile. Copyright © 2005 John Wiley & Sons, Ltd.

Lorena Martinezzavala - One of the best experts on this subject based on the ideXlab platform.

  • impact of different parts of unpaved Forest Roads on runoff and sediment yield in a mediterranean area
    Science of The Total Environment, 2009
    Co-Authors: Antonio Jordanlopez, Lorena Martinezzavala, N Bellinfante
    Abstract:

    Abstract Surface runoff and sediment production on unpaved Forest Roads in a humid Mediterranean mountainous area has been studied using a simple portable rainfall simulator at an intensity of 90 mm h− 1. Thirty six rainfall simulations were carried out on road plots: on the roadbank (12), on the sidecast fill (12), and on the roadbed (12). On the roadbanks, the steady-state runoff coefficient was 85.9% and runoff flow appeared after 63 s on average. On the sidecast fills, the steady-state runoff coefficient was 58.6% and mean time to runoff was 48 s. Finally, on the roadbeds, the steady-state runoff coefficient was 21.5% and mean time to runoff was 41 s. The highest soil loss rate was found on the roadbanks (486.7 g m− 2), mainly due to low plant cover, soil texture and rock fragments. The total soil erosion on the roadbanks was 3 and 18 times higher than those from the roadbeds and the sidecast fills, respectively. As a consequence, roadbanks can be considered the main source of sediments on the studied sites, but the function of unpaved Forest Roads as source points for runoff generation is more important.

  • soil loss and runoff rates on unpaved Forest Roads in southern spain after simulated rainfall
    Forest Ecology and Management, 2008
    Co-Authors: Antonio Jordan, Lorena Martinezzavala
    Abstract:

    Abstract We have studied the surface runoff and sediment production on unpaved Forest Roads in Los Alcornocales Natural Park (southern Spain) using a simple portable rainfall simulator at an intensity of 72 mm h−1. Thirty rainfall simulations were carried out on 10 road plots: on the roadbank (10), on the sidecast fill (10), and on the roadbed (10). On the roadbanks, the runoff coefficient was 58% and runoff flow appeared after 60–90 s. On the sidecast fills, the runoff coefficient was 27% and time to runoff was 5–108 s. Finally, on the roadbeds, the runoff coefficient was 51% and time to runoff was 25–89 s. The highest soil loss rate was found on the roadbanks (106 g m−2), due to slopes, the existence of loose colluviums, and a low plant cover. The total soil loss from the roadbank was 5 and 6 times higher than those from the roadbed and the sidecast fill, respectively. The sediment concentration increased during the first 6–8 min from the beginning of the simulations and then decreased steadily due to the loss of fine soil surface particles and porosity changes. Statistical analysis shows that plant cover on roadbanks, sidecast fills, and roadbeds has a significant effect on runoff. Rock fragment cover and slopes on the roadbank and the sidecast also influence runoff significantly. The behavior of roadbanks was similar to that of other cultivated soils and abandoned sloping fields. Sidecast fills had the same response as abandoned terraces or non-vegetated road embankments. Reducing the roadbank angle by approximately 40% and increasing the plant cover to 35–40% are necessary for keeping erosion below 18 g m−2, as it was on the sidecast fills.

Amir Modarres - One of the best experts on this subject based on the ideXlab platform.

  • use of rice husk ash as a stabilizer to reduce soil loss and runoff rates on sub base materials of Forest Roads from rainfall simulation tests
    Catena, 2017
    Co-Authors: Mehran Nasiri, Majid Lotfalian, Amir Modarres
    Abstract:

    Abstract The impact of rice husk ash (RHA) as a stabilizer to reduce soil loss and surface runoff rates on sub-base materials of Forest Roads has been studied using a portable rainfall simulator at an intensity of 52 mmh− 1. Thirty rainfall simulations were carried out on different combinations of materials: on the natural sub-base soils (5), on the materials stabilized with pure lime (5), and on the materials stabilized with different percent of RHA and lime (20). Results indicated that on natural sub-base soils, the runoff coefficient was 53.6% and mean time to runoff was 87 s. On the materials stabilized with pure lime, the runoff coefficient and mean time to runoff were measured 58.7% and 63 s, respectively. The lowest runoff coefficient was measured 36.6% on the combination of soil + 6% lime + 9% RHA. However, the highest mean time to runoff was recorded 198 s on the combination of soil + 4% lime + 9% RHA. The maximum and minimum soil loss rates were found on the natural sub-base soils (212.2 g m− 2) and on the combination of soil + 6% lime + 9% RHA (162.4 g m− 2), mainly due to changes in maximum dry density (MDD), plasticity index (PI), optimum moisture content (OMC) and CBR of materials. On the basis of the results, we concluded that the rice husk ash not only increases the materials quality in soil stabilization methods with lime, but also reduces the runoff and soil loss rates on unpaved Forest Roads.