Abstracts: Transportation Corridor Vegetation Management
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High-Altitude Revegetation Experiments on the Beartooth Plateau Park and Carbon Counties, Montana, and Park and Bighorn Counties, Wyoming
Liz Payson (Phone: 303-830-1188, Email: firstname.lastname@example.org), and Richard Trenholme, ERO Resources Corporation, 1842 Clarkson Street, Denver, CO 80218; and Jennifer Corwin (Phone: 720-963-3682, Email: email@example.com), Federal Highway Administration, 555 Zang Street, Room 259, Lakewood, CO 80228
The Federal Highway Administration (FHWA) Central Federal Lands Highway Division is conducting a comprehensive study to identify techniques that maximize the opportunities for successful revegetation along high altitude portions of U.S. Highway 212, the Beartooth Highway. A portion of the Beartooth Highway that travels through alpine and subalpine areas is proposed for reconstruction by the FHWA. FHWA has conducted revegetation experiments in the form of test plots and seed-increase experiments since 1999 to identify the most successful revegetation techniques for revegetating alpine areas.
Over a period of four years, four revegetation experiments have been placed on the Beartooth Highway to investigate the most effective revegetation techniques for subalpine and alpine disturbances. Variables tested include topsoil placement, organic amendments, surface mulches, seeding rate, and seed source (locally collected or commercial sources).
In addition, three seed-growout experiments have been conducted at a nearby farm in Manderson, Wyoming, to assess whether seed collected on the Beartooth Plateau can be produced in large quantities and used to revegetate disturbed areas associated with construction. These seed-growout experiments tested the potential to commercially produce a variety of alpine and subalpine forb, grass, and sedge seed. The results from this study will assist highway departments, mining, oil and gas, and utility companies, and other land-management agencies in revegetating high-altitude disturbances to meet requirements of various state, local, and federal permits. The study makes conclusions about the effectiveness of several revegetation items, such as seeding rate, type of organic amendment, fertilizer reapplication, and topsoil placement and makes recommendations for further study regarding native-seed propagation.
Mitigation for Dormice and Their Ancient Woodland Habitat Alongside a Motorway Corridor
Warren Cresswell (Phone: 01453-731231, Email: firstname.lastname@example.org), Director, and Stephanie Wray (Phone: 01453-731231, Email: email@example.com), Director, Cresswell Associates, Stroud, GL GLS 2QG, UK
The M2 motorway-widening scheme in Kent, England was set within a constrained, environmentally sensitive corridor. Ecologists were involved from the earliest stages of the project and throughout the planning, development, and implementation phases they worked alongside the design engineers to develop pragmatic solutions to the potential impacts of the scheme.
One of the most significant impacts was on the areas of ancient woodland that abut the existing motorway. Since the widening was on-line or adjacent to the existing motorway, the widening proposals sought to minimize the ancient woodland land-take, but some loss was inevitable.
The scheme was discussed at length with the statutory consultees. One option considered was a contribution to offsite habitat creation (mitigation banking). Instead, a scheme for the creation of new woodland adjacent to the scheme was developed. However, rather than simply planting trees onto a bare site, an ambitious proposal to translocate the existing ancient woodland soil to the new site was implemented.
From the outset, the ancient woodland topsoil was identified as a valuable resource, having developed in shaded conditions for hundreds of years and containing a considerable diversity of woodland seeds, bulbs, micro-organisms, and invertebrates. The majority of the woodlands affected by the scheme were commercial sweet chestnut coppice of little intrinsic nature conservation value, but all of the woodlands supported the protected hazel dormouse.
Over a year before the contract to widen the M2 was let, the ecological advance works began on site. The trees within all of the strips of woodland where the motorway widening would take place were coppiced during winter, using hand-held tools and without permitting vehicles onto the ancient woodland soil. This work was timed to coincide with the period when dormice would be hibernating on the ground. On waking from hibernation in spring, the dormice moved into the canopy of the remaining woodland, where their habitat had been enhanced by the provision of artificial nest sites and woodland-management techniques, including selective coppicing and replanting.
The following autumn, the ancient woodland soil (with its seed-bank intact) was carefully excavated and re-spread on a specially prepared 'receptor site.'
One hundred mature coppiced hazel trees were transplanted from the area of the widening to the new site to provide food for dormice. Also, 60,000 new trees of an appropriate diverse species mix and of local provenance were planted. Piles of decaying timber were also assembled to provide a habitat for fungi and dead wood invertebrates.
The new woodland that has been created connects three existing woods, enhancing their nature conservation value and providing a linking function as a substantial ‘wildlife corridor.' There is also a public footpath and bridleway, suitably fenced throughout the length of the site so that the new woodland can be enjoyed by local people.
The translocated ancient woodland soil will give the new woodland a valuable start in its development by providing many of the important components of a woodland ecosystem. The site is being monitored closely for at least the next 10 years, and each successfully transferred element of the habitat is being carefully logged and its progress to full establishment recorded. Five years on, the woodland is developing well. There is a distinct woodland ground flora, with carpets of bluebells in the spring, and woodland invertebrates are still present. The tiny fragment of retained woodland in the center of the site still holds a population of dormice. The translocated and new Hazel are beginning to fruit heavily so that a further eight hectares of habitat will soon be available to the population.
Response of Acacia Species to Soil Disturbance by Roadworks in Southern New South Wales, Australia
Peter G. Spooner (Email: firstname.lastname@example.org), Institute of Land, Water and Society, Charles Sturt University, P.O. Box 789, Albury NSW 2640, Australia
Heavy machinery is regularly used throughout the world to maintain infrastructure corridors. The purpose of this study is to investigate the response of roadside populations of three Acacia shrub species to soil disturbance from roadworks. Results were highly variable. However, resprouting and seedling emergence led to a 6.2 percent population increase at four road reserves. Two years after grading, there was significant resprouting of A. decora and resprouts reached a mean height of 72 cm. One year after disturbance, 71 percent of A. decora resprouts flowered and 49 percent also set viable seed. In contrast, there was patchy seedling emergence of A. pycnantha and A. montana. These results show that grading of roadsides appears to favor plants with strong resprouting ability and that the scale of response depends on the plants life-history attributes and the prevailing disturbance regime. Further studies of individual plant responses to soil disturbance can only better our understanding of plant dynamics in road and other transportation corridors.