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Copyright of Western North American Naturalist is the property of Monte L. Bean Life Science Museum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ecological consequences of slash pile burning are a concern for land managers charged with maintaining forest soil productivity and native plant diversity. Fuel reduction and forest health management projects have created nearly 150,000 slash piles scheduled for burning on US Forest Service land in northern Colorado. The vast majority of these are small piles (<5 m diameter). Similar to larger piles, we found that burning small piles had significant immediate effects on soil nutrients and physical and chemical properties and native plant cover. To evaluate the need to rehabilitate small piles and compare the effectiveness of treatment options, we examined soil and plant responses to treatments designed to alter soil nutrients, moisture and temperature and to increase seed availability. We compared four surface treatments (soil scarification, woodchip mulch, tree branch mulch, untreated scars), with and without addition of a native seed mixture. Natural recovery and treatment effects were examined for 2.5 years after pile burning at 19 conifer forest sites along the Colorado Front Range. Woodchip mulch had dramatic effects on soil moisture, temperature, decomposition and inorganic soil N compared to the other treatments, untreated scars or unburned areas; woodchip mulch also suppressed plant establishment. Seeding increased total native species richness as expected, but had marginal effects on forb cover and no effect on graminoid cover. Soil N availability and plant cover did not differ from unburned areas in the absence of surface or seeding treatments within two years of pile burning. Neither reduced seed availability nor altered soil properties following burning hindered revegetation of these small burn scars by native herbaceous plants. Our findings indicate that rehabilitation may not be required for small burn pile scars except in sensitive areas, such as those with water quality and invasive plant concerns. [ABSTRACT FROM AUTHOR]

Heap leach processing for extraction of gold began in 1985 at Summitville Mine in southwestern Colorado, and by 1994 the site was declared a Superfund Site by the USEPA. In 1995, we began a science-based approach aimed at restoring 200 ha of highly disturbed land. The short-term goal of the restoration was aimed at stabilizing soils and preventing off-site movement of metal-containing sediments. The longer-term goal was to encourage development of a plant community that resembled a reference condition. Here, we describe our systematic approach for restoration that included identification of constraints to plant establishment and growth, a greenhouse experiment to screen 36 growth medium treatments, and a field experiment to test a subset of best performing treatments. A greenhouse study identified several promising treatments that were implemented in the field experiment, which ultimately identified a single best approach (30 cm of waste rock amended with lime and mushroom compost and covered with 15 cm of limed, fertilized stockpiled topsoil). From 1999 to 2001, the site was re-contoured, amended, and seeded. From 2002 to 2009, we documented an increase in uniformity of vegetation cover on restored areas, an increase in species richness, and a significant shift from a plant community dominated by seeded species, to one more similar to a reference plant community as evidenced by a non-metric multi-dimensional scaling analysis. Overall, these results demonstrate how initial well-planned treatments can encourage a favorable trajectory for restoration of a seeded site, while also demonstrating the utility of this science-based approach for dealing with restoration of a highly disturbed landscape. [ABSTRACT FROM AUTHOR]

1. Plant community succession has been a major area of study over the past century with recent research focusing on the importance of initial colonisers following disturbance. Seed addition can accelerate ecosystem regeneration and is a method commonly used by land managers to restore disturbed lands. However, few studies have examined the effects of seeding treatments on long-term community composition. 2. A study was established in 1984 in the Piceance Basin of northwest Colorado to examine how various revegetation seed mixes affect plant community development following disturbance. The site was surveyed again in 2008 and 2009 to assess long-term community development. 3. Initial seed mix resulted in significant differences in plant community composition after 25 years. Seeding with native and exotic early-seral species resulted in a community with significantly more exotic species and mid-seral shrubs, while seeding with native late-seral species resulted in a community dominated by perennial grasses. Additionally, an unseeded control resulted in a vegetation community dominated by both perennial grasses and mid-seral shrubs, but community composition at the species level was considerably different from that of the seeded treatments. However, the plant community composition of each of the three treatments was significantly different from an adjacent undisturbed reference area, which was dominated by the late-seral shrub, Artemisia tridentata, and perennial grasses. 4. Synthesis and applications. Our results illustrate how initial colonisers (seed mix) can strongly affect subsequent community assemblage after 25 years of development. Restoration ecologists should give considerable thought to the species used in a restoration seed mix to ensure the success of restoration designs and to create the desired community assembly and associated ecosystem services. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the long-term effects of biosolids amendment on restoration of disturbed sagebrush steppe habitat in northwestern Colorado. Twenty-four years after biosolids amendment, soil fertility and plant community development were studied in replicated plots receiving various biosolids amendments on two different substrates. The two substrates used were a subsoil, determined to have low initial fertility, and a topsoil over retorted shale substrate, determined to have relatively high initial fertility. Results suggest that biosolids amendments have long-lasting effects on soil fertility and plant community composition, but these effects vary between the two substrates that were utilized. Within the plots established on subsoil, the long-term effect of biosolids was a reduction in plant species diversity and dominance by perennial grasses. On the topsoil substrate, there was a decrease in perennial grasses and an increase in shrub dominance with increasing biosolids. Results demonstrate the importance of considering initial soil conditions, seed mixture, and biosolids application rate when using biosolids for restoration of disturbed sagebrush steppe habitat. The long-term effects of the biosolids treatments at this site demonstrate the need to consider restoration treatment effects over longer and more ecologically meaningful time frames. [ABSTRACT FROM AUTHOR]

AbstractThe geology of Mesa Verde National Park (MVNP) poses unique problems to road construction and maintenance. Major geologic formations of the Park consist of an overlying resistant sandstone cap underlain by highly erodable shales. Once this sandstone cap is removed, the shales are easily eroded away, creating the notable mesas of the region. In many places, road construction has removed the sandstone layer and vegetation resulting in unaesthetic barren slopes that require continual maintenance and have proven difficult to revegetate. An experiment was conducted to evaluate the effectiveness of several cultural techniques combined with seeding and transplanting indigenous plants for revegetation of these roadcut slopes. Techniques evaluated were fertilization, mulching, soil pitting, and polyacrylamide amendments. Replicated test plots were established at three roadcut sites in MVNP to evaluate these techniques by measuring percent plant cover by species over a 4-year period. A combination of seeding grasses and transplanting forbs and shrubs appeared to be the optimal way to maintain species diversity and structure on the roadcuts while accomplishing the goal of revegetating these difficult sites. The perennial forb Aster glaucodes and the shrub Artemisia ludoviciana showed high survival when transplanted in the experimental roadcut sites. These species, as well as the perennial grass Pascopyrum smithii, also established well from seed. The addition of an organic fertilizer, in combination with mulch, proved to be the most effective method of improving vegetation cover for these and other transplanted species. [ABSTRACT FROM AUTHOR]