COLORADO DIVISION OF WILDLIFE – AVIAN RESEARCH …€¦ · COLORADO DIVISION OF WILDLIFE – AVIAN RESEARCH PROGRAM ANNUAL PROGRESS REPORT February 3, 2009 TITLE: Restoring energy

COLORADO DIVISION OF WILDLIFE – AVIAN RESEARCH PROGRAM ANNUAL PROGRESS REPORT

February 3, 2009 TITLE: Restoring energy fields for wildlife AUTHOR: Danielle B. Johnston PROJECT PERSONNEL: Bill DeVergie, Area Wildlife Manager JT Romatze, Area Wildlife Manager Ron Velarde, Regional Manager JC Rivale, Property Technician Jim H. Gammonley, Avian Research Leader Period Covered: December 1, 2007 – January 15, 2009 All information in this report is preliminary and subject to further evaluation. Information MAY NOT BE PUBLISHED OR QUOTED without permission of the author. Manipulation of these data beyond that contained in this report is discouraged.

ABSTRACT In 2008, we initiated a study to improve techniques to restore sagebrush (Artemesia sp.) habitats impacted by oil and gas development in the Piceance Basin of northwestern Colorado. Technique trials were replicated over a gradient of elevation and weed prevalence in order to draw inferences over a large portion of the basin. In the first experiment, pipeline disturbances were simulated at six locations differing in prevalence of the troublesome weed downy brome (Bromus tectorum). Two levels of herbicide [Plateau™ (ammonium salt of imazapic) at 420 g/acre with glyphosate at 560 g/acre or no herbicide] were crossed with 5 levels of soil compaction, and then the sites were seeded with a mixture of native forbs, shrubs, and grasses. In the second experiment, well pad disturbances were simulated at 12 locations differing in weed presence, elevation, and precipitation. Preliminary results from the first experiment indicate that the herbicide treatment was effective at reducing November downy brome seedling density at 2 of 6 sites, and that at least one soil manipulation involving soil tillage and/or compaction was effective at 3 of 6 sites. Sites with significant treatment effects tended to be lower in elevation and have higher pre-treatment downy brome cover. It is likely that too few seedlings at higher elevation, lower brome cover sites had emerged at the time of seedling counts for treatment effects to be apparent. Plans for 2009 include continuing to monitor experiment 1 as well as respreading topsoil and implementing crossed treatments of weed control, fencing, and planting techniques for experiment 2. Treatment implementation is expected to be completed by November of 2009, and monitoring is expected to continue through 2014.

Restoring Energy Fields For Wildlife Annual Progress Report

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RESTORING ENERGY FIELDS FOR WILDLIFE Annual Progress Report (December 1, 2007 – January 15, 2009)

Danielle Bilyeu Johnston

PROJECT OBJECTIVES

The main objective of this project is to provide information on restoration techniques which maximize wildlife habitat value of sagebrush (Artemesia sp.) habitats impacted by oil and gas development in northwestern Colorado. The first experiment addresses weed control techniques which may facilitate establishment of mixed plant communities. The hypotheses being tested are:

• If the competitive balance between downy brome and native plant species is affected by soil density, then a soil density treatment may be found that optimizes native plant establishment.

• If Plateau® herbicide (ammonium salt of imazapic) reduces establishment of native forbs, then a more desirable native plant community may be established if Plateau use is avoided.

• If downy brome cover in the adjacent plant community is an indicator of need for weed control, then the weed control technique producing the most desirable plant community will vary by site with downy brome cover.

The second experiment addresses a need for synthetic information on which restoration techniques should be used in which areas. The hypotheses to be tested may include:

• If wind dispersal of downy brome seeds from the adjacent community increases competition from downy brome in the reclamation area, then protecting the reclamation area with wind screens during downy brome dispersal may increase native plant establishment.

• If weed seed concentrations in topsoil are such that needed weed control measures would preclude establishment of less competitive native plants, then a more desirable plant community may be established if topsoil is abandoned.

• If ungulate herbivory on seedlings has a negative effect on seedlings’ future productivity, then protecting seedlings with wildlife-proof fencing for 3 years will result in higher annual forage production than will 3 years of protection with livestock-proof fencing.

• If favorable microsites are necessary for seedling establishment, then a more favorable plant community may be established if the soil surface is roughened prior to seeding.

• If the value of and need for specific reclamation practices varies with climatic and soil conditions, then the treatment producing the most desirable plant community will vary by site according to site elevation, precipitation, and/or geography.

SEGMENT OBJECTIVES

NOTE: A few objectives which have changed since the study plan was completed last year are outlined here.

• The objective of creating disturbances for research purposes was added because it was found that ensuring continued use of actual pipelines and drill pads for the purpose of reclamation research was not feasible.

• The objective of seeding experiment 1 sites with desired species for reclamation was added, and the objective of sampling and analyzing soils for concentration of viable downy brome seeds was abandoned. This is because finding a treatment which reduces


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brome seed concentration may not be helpful if that treatment also reduced native plant establishment.

• The objective of measuring pre-treatment soil bulk density at experiment 1 sites in order to determine if the soil should be ripped to relieve deep soil compaction was dropped. This is because safety protocols prevent ripping of actual pipelines.

• The objective of measuring bulk densities of soil compaction treatments using a penetrometer was postponed until spring of 2009 because penetrometer readings are more reliable when soils are moist, and soil-recharging rain events did not occur in the fall of 2008.

Objectives for experiment 1:

1. Select 6 research locations in northwestern Colorado fitting the following criteria: Landowner is willing to permit continued use of the property for

research purposes for the foreseeable future Sagebrush is a dominant component of the plant community At least some downy brome is present Site can be accessed with heavy equipment Site has less than 10% slope Suitable conditions found for at least a half-acre area

2. Create disturbances which simulate the vegetation loss, topsoil movement, and subsoil mixing typical of pipeline installation at each location.

3. Assess plant community of research areas with point-intercept transects. 4. Assess soil bulk density of native community and disturbed areas using 11 soil cores

taken to a depth of 30 cm at each site. 5. Delineate plots within disturbed areas; apply soil bulk density adjustment treatments,

including light, medium, and heavy compaction treatments as well as a bulk density reduction treatment (disking) to plots.

6. Apply herbicide treatment to one-half of each site. 7. Drill-seed native grasses and forbs. 8. Fence research areas with 8-ft high wildlife fencing. 9. Broadcast sagebrush seed over snow.

Objectives for experiment 2:

1. Select 6 additional research locations in northwestern Colorado which span a higher elevational range than those created for experiment 1. Sites must meet all criteria listed for experiment 1, except for the requirement that downy brome be present.

2. Create disturbances which simulate the vegetation loss, topsoil stockpiling, and subsoil cut-and-fill typical of well pad installation at all 12 research locations.

INTRODUCTION

Preserving wildlife habitat quality in oil and gas fields requires effective restoration of impacted areas. Successful restoration entails preventing soil loss, overcoming the threat of weed invasion, and promoting natural plant successional processes so that diverse native plant communities are established. A detailed knowledge of soils, climate, topography, land use history, and plant competition is needed to accomplish this goal, and optimal choices of reclamation techniques are site-specific. The need for site-specific knowledge often prompts local reclamation trials by organizations such as coal mining companies which cause large-scale disturbances. In oil and gas fields, however, local reclamation trials are difficult to implement due to the spatial pattern of disturbance.


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In contrast to coal mines, which typically result in a small number of large disturbances, oil and gas fields result in a large number of smaller disturbances, each connected by a web of pipelines and access roads which may extend across hundreds of thousands of acres. The complexities of gathering knowledge at the appropriate scales, administering recommendations for the multitude of sites involved, and enforcing appropriate standards over such large areas often results in reclamation that falls short of the most basic standards (Avis 1997, Pilkington and Redente 2006). Addressing these challenges is imperative, as the fragmented pattern of development means that wildlife and wildlife habitat are affected over a much larger area than that directly occupied by development activities. For instance, Greater Sage-Grouse (Centrocercus urophasianus) populations (Walker et al. 2007) and Mule Deer (Odocoileus hemionus) habitat use (Sawyer et al. 2006) may decline within large buffer areas surrounding development. Non-native species establishment due to development (Bergquist et al. 2007) could reduce wildlife habitat quality over large areas if disturbances are allowed to provide vectors for weed invasion into otherwise undisturbed habitat (Trammell and Butler 1995). Because of this threat, preventing weed invasion through successful restoration of all impacted areas is a top management priority for wildlife. The goal of this study is to promote such restoration by replicating tests of promising techniques at the scale of an oil field. The Piceance Basin in northwestern Colorado provides an ideal laboratory for conducting a large-scale study of restoration techniques. The area is currently experiencing an unprecedented level of natural gas development, provides critical habitat for the largest migratory mule deer herd in the United States, and has a complex topography which ensures that a wide range of precipitation, soil development, and plant community types are represented. Furthermore, the Piceance Basin is at the edge of the eastern expansion of the troublesome weed downy brome (Bromus tectorum, cheatgrass), allowing an opportunity to assess control measures for this weed in an area where such measures may have the most effect. Downy brome invasion presents a serious obstacle to effective restoration in the study area (Pilkington and Redente 2006). Because of this, the initial phase of this research study specifically targets control techniques for this weed. Two types of brome control measures, herbicide application and soil manipulation, are tested in six different locations spanning the elevation and precipitation range where downy brome is currently present. In the second phase of this research project, weed control technique trials are crossed with tests of the effectiveness of fencing techniques and seeding methods at twelve locations spanning the entire elevational range of the area. The focus is on sagebrush (Artemesia tridentata) communities, because of the need for better techniques for re-establishing these communities (Lysne 2005), their widespread distribution, and their importance to wildlife.

STUDY AREA

The Piceance Basin study area is in Rio Blanco and Garfield Counties, Colorado, USA (Figure 1). Elevation increases gradually from north to south as one travels from Piceance Creek (~1,800 m) to the top of the Roan Plateau (~2,500 m), then drops off sharply at the Book Cliffs to the Colorado River Valley (~1,500 m). Precipitation and temperature vary across the region with both elevation and latitude; more northerly are colder and receive less precipitation than southerly sites of similar elevation. Northernmost sites receive approximately 280 mm per year, 40% as snow. The southerly Colorado River Valley sites receive approximately 340 mm of precipitation per year, 25% as snow. The wettest, highest elevation sites are at the southern edge of the Roan Plateau, and receive approximately 500 mm per year, 60% as snow. Low elevations are characterized by Wyoming big sagebrush, downy brome, Indian ricegrass (Oryzopsis hymenoides), western wheatgrass (Agropyron smithii), prairie junegrass (Koeleria cristata), and globemallow (Sphaeralcea coccinea) in flatter areas with a mixture of pinyon pine (Pinus sp.) and Utah juniper (Juniperous utahensis) on steeper slopes and greasewood (Sarcobatus


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vermiculatus) in floodplains. High elevations are characterized by mountain big sagebrush, mountain brome (Bromus marginatus) and diverse forbs in flatter areas, serviceberry (Amelanchier alnifolia), snowberry (Symphoricarpos albus), and Gambel’s oak (Quercus gambelii) on slopes, and aspen (Populus tremuloides) mixed with Engleman spruce (Picea engelmanii) in the highest elevation, north-facing slopes.

METHODS EXPERIMENT 1 Our study focuses on those weed control techniques which may be compatible with the development of diverse, native plant communities, as these are the communities which best serve the needs of wildlife. As such, the use of competitive non-native grasses, which can prevent normal plant succession (Christian and Wilson 1999), is avoided. The costs and benefits of herbicide application in different environments is compared with those of soil manipulations, which may offer a weed control alternative that is less detrimental to desirable plants. The herbicide we are investigating is Plateau ™ (ammonium salt of imazapic), as it has been shown to reduce downy brome with little effect on some perennial grasses (Kyser et al. 2007). However, it may also reduce vigor and density of established forbs (Baker et al. 2007), and little is known about its effect on germination of desirable forbs. An advantage of oil and gas disturbances for restoration is that they are amenable to soil and tillage manipulations, as the ground is already disturbed and access routes for heavy equipment have already been created. In agricultural settings, combining lower levels of herbicide with tillage treatments, such as disk cultivation, has proven effective for controlling weeds (Mulugeta and Stoltenberg 1997, Mohler et al. 2006). Soil manipulations may be particularly effective for controlling downy brome because downy brome is sensitive to seed burial (Wicks 1997), does not germinate well in even slightly compacted soil surfaces (Thill et al. 1979), and is less competitive in denser soils (Kyle et al. 2007). Several soil manipulations are tested in this study in an effort to find a manipulation that may control downy brome while promoting establishment of native plants. Site selection and preparation

Six sites: Yellow Creek 1 (YC1), Yellow Creek 2 (YC2), Ryan Gulch (RYG), Wagon Road Ridge (WRR), Grand Valley Mesa (GVM) and SK Holdings (SKH) were selected within the Piceance Basin (Figures 1, 3-8). Sites shared the following characteristics: slope <15%, downy brome present, and sagebrush cover >10%. Exact location of sites was constrained by landowner preferences. Soil samples were taken from the top 20 cm from 5 locations and aggregated at each site. These will be analyzed for organic matter content pH, electrical conductivity, nitrogen, and phosphorus in 2009.

At each site, two simulated pipeline disturbances were created, each measuring 11m wide by 52m long. Site creation began the week of Aug. 20th. A bulldozer was used to scrape the vegetation, pile it off site, and scrape 15 cm of topsoil. Topsoil was stockpiled in windrows less than 2 m in height at the narrow end of the site. Next, a backhoe was used to create trenches measuring 1 m wide by 1 m deep, which were left open for 2 weeks before being refilled. Finally, stockpiled topsoil was spread evenly over the site. This work was completed Sept. 10th. Study Design The study design is a factorial split-plot experiment with 2 levels of herbicide application crossed with 5 levels of tillage. Herbicide treatments were randomly assigned to simulated pipeline strips (the split-plots), and tillage treatments were randomly assigned to subplots within


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each pipeline strip (Figure 2). Pipeline strips were separated by 15 m in order to minimize effects of herbicide drift. Each plot measured 11m by 10m. Treatment implementation

Soil manipulations were completed between Sept 13th and Oct. 7th. The five soil treatments implemented on each pipeline were: Control (C), Fluffy (F), Light (L), Heavy (H) and Medium (M). In C plots, bulldozer and backhoe tracks were left in place. The soil surface varied from smooth to very rough. F plots received a disking treatment to 4 inches, and the soil surface was somewhat rough due to the disk tracks. L plots received one pass with a non-vibratory roller (Singh et al. 1976) pulled behind an ATV. The roller weighed 900 lbs, and the soil surface was left smooth. H plots received 4 passes with a vibratory drum roller (Wacker DH-12), and the soil surface was left smooth. M plots received a treatment designed to create slight soil compaction at the surface, while avoiding heavy compaction of the rooting zone, which can restrict root growth and compromise establishment of deeply-rooted perennial plants (Thompson et al. 1987). M plots were disked to 4 inches, then wetted to 1 cm using an ATV tow sprayer and rolled 5 times with a non-vibratory roller. The soil surface was left smooth and crusted with occasional ATV tracks. At the Yellow Creek sites, implementing the H treatment was not possible because the sites were located too far from the road. In lieu of the H treatment, a modified treatment (M2) was implemented that included wetting the surface to 1 cm and rolling 5 times with a non-vibratory roller without disking the surface first. Herbicide was applied to one randomly selected pipeline strip on October 6 at WRR and RYG, on October 15 at YC1 and YC2, and on October 22 at SKH and GVM. WRR and RYG were treated earliest because downy brome emerged first at these sites. The plants were mostly at the 1-leaf stage (about 5 cm tall) at the time of application at these sites. Downy brome had just begun emerging at the Yellow Creek sites at the time of application, and had not emerged at all at the time of application at SKH or GVM. At all sites, a mixture of Plateau™ (ammonium salt of imazapic) [420 g/acre (6 oz./acre)], glyphosate [560 g/acre (8 oz./acre)], and methylated seed oil (2% v/v) were applied using an ATV tow sprayer (Agri-Fab 45-0424). The rate of Plateau™ application was chosen as a compromise between the 700g/ac rate, which has been shown to provide good brome control at the expense of strong negative effects on native forbs (Baker et al. 2007) and the 280 g rate, which has been shown to avoid serious negative effects on most desirable species but provides only moderate brome control (Bekedam 2004). Glyphosate was added because downy brome had emerged at some sites at the time of application, and Plateau™ is less effective on emerged plants (BASF representative, personal communication). Methylated seed soil was added to facilitate bonding of the herbicide to leaf surfaces. Sites were seeded the week of October 17th using a Tye Pasture Pleaser rangeland drill, which was calibrated so that seed would not be planted more than 1 cm deep in tilled soil. Drill rows were about 25 cm apart, and the drill produced a minimal amount of soil disturbance. All sites received the same seed mixture (Table 1). Grasses and shadscale species were mixed together, as were all forb species. Grass/shadscale and forb mixtures were seeded in separate rows by taping poster board dividers in the seed box, and placing seed mixes in alternating divisions. Rice hulls were added at 50% v/v in order to keep seeds of different sizes suspended evenly in the mixtures (St. John et al. 2005). Wyoming big sagebrush seed collected from Dry Creek Basin, Colorado, an area with similar temperature and moisture characteristics to the study area, was broadcast seeded onto snow in mid-January. Plots were seeded at a rate of 8.6 pounds pure live seed (PLS) per acre. This low seeding rate was chosen because lower seeding rates facilitate establishment of mixed stands (Redente et al. 1984).

Because pipeline right-of-ways can be attractive to wildlife and cattle, all sites were fenced to allow analysis of the effectiveness of treatments in the absence of trampling and browsing. Eight foot high fences were completed at SKH and GVM in late October, and the remaining fences were completed in early December. A 1.5 m buffer strip was left between the


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edge of study plots and the fence. Site visits in early January, 2009 revealed that snow drifting due to the fences was negligible. Table 1. Seed mixture used at experiment 1 sites.

Scientific Name Common Name PLS/acre

Live seeds/

m2

forbs Achillea lanulosa Western yarrow 0.10 67

Erigonum umbellatum sulfur flower buckwheat 1.03 53

Hedsarum boreale Utah sweetvetch 0.44 11

Heterotheca villose hairy golden aster 1.11 137

Linum lewisii Lewis flax 0.38 28

Packera multilobata lobeleaf groundsel 0.10 67

Penstemon strictus Rocky Mountain penstemon 0.33 23

grasses Achnatherum lymenoides Indian ricegrass (Nezpar) 0.83 33

Agropyron smithii Western wheatgrass 0.40 11

Agropyron spicatum bearded bluebunch wheatgrass P-7 0.38 11

Agropyron spicatum bearded bluebunch wheatgrass Secar 0.36 10

Agropyron trachycaulum slender wheatgrass 0.24 10

Elymus elymoides bottlebrush squirreltail 0.45 21

Koeleria macrantha prarie junegrass 0.18 105

Poa secunda sandberg bluegrass 0.26 68

Stipa viridula green needlegrass 0.68 22

shrubs Artemesia tridentata ssp. Wyomingensis Wyoming big sagebrush 0.33 246

Atriplex canescens fourwing saltbush 0.54 7

Atriplex confertifolia shadscale saltbush 0.47 7

total 8.60


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Data collection

To characterize soil bulk density at each site and quantify the effect of simulated pipeline construction on bulk density, we sampled 11 soil cores per site using a drop-hammer double cylinder soil corer (AMS instruments model 404.50). Five cores were taken in undisturbed locations around the perimeter of the site, and 3 cores were taken from each of the 2 pipeline strips prior to soil treatment implementation. Cores were taken to a depth of 30 cm and were divided into six 5cm depth increments. Bulk density of each fraction is currently being determined by drying each sample to a constant weight and dividing dry weight by the volume of the sample (Krzic et al. 2000). Pre-treatment percent plant cover was assessed using 4 point-intercept transects 10 m in length placed systematically around the perimeter of each site, and hits were recorded to species following the method outlined by Herrick (Herrick et al. 2005). Percent cover was assessed in late August at all sites.

Seedling density counts were performed at all sites between Nov 4th and Nov 18th. At the time of counts, seedlings at most sites were just emerging or were at the 1-leaf stage, with the exception of RYG, where seedlings had between 1 and 7 leaves. Seedling counts were done within circles 62 cm in diameter placed randomly within each of 9 cells created by placing an imaginary “tic-tac-toe” board over each plot. A 1 m wide buffer zone surrounding each plot was excluded from measurement. A total of 90 counts were done per site. Statistical Analysis Downy brome seedling density was analyzed using ANOVA in SAS PROC MIXED for a split-plot, factorial design with two main effects [(tillage/compaction treatment – 5 levels) and herbicide (2 levels)] and their interaction as fixed effects and with site as a random effect. Two groups of hypotheses were used to control family wise error rate to the ά = 0.05 rate: those concerning effectiveness of the soil manipulations (resulting in 4 pairwise comparisons between the 4 treatments and the control) and that concerning effectiveness of the herbicide treatment (resulting in one comparison between treatment and control). A statistical significance level of ά/4 = 0.0125 was applied to the comparisons of soil manipulations to ensure the Bonferonni-corrected ά = 0.05 error rate for group. EXPERIMENT 2 Site selection and preparation Due to logistical constraints, six of the sites for experiment 2 are located adjacent to experiment 1 sites. The remaining six sites, Scandard, Snowpile, Girls’ Claims, Square S, Mountain Shrub 69 Rd, and Sagebrush 69 Rd., were selected to represent the upper end of the elevational range of sagebrush habitats in the Piceance Basin (Figure 1). The model system for experiment 2 is simulated well pad disturbances. Well pad disturbances differ from those of pipelines in two ways: Topsoil is typically stockpiled for a much longer time (1 to 3 years vs. 2 to 6 weeks), and cut-and-fill activities result in greater disturbance to subsoil. Simulated well pads measuring 35 X 55 m were created between August 12th and August 21st at SKH, GVM, RYG, WRR, YC1 and YC2 sites (hereafter lower elevation sites). Similar pads were created between November 7th and 18th at Scandard, Girls’ Claims, Square S, Sage 69 Rd, Mountain Shrub 69 Rd, and Snowpile (hereafter higher elevation sites). All sites have less than 10% grade. At all sites, vegetation was grubbed off and piled outside of the study area or placed around the perimeter of the study area to reduce run-on and/or erosion from runoff. Fifteen cm of topsoil was then scraped and stockpiled in windrows no higher than 2 m along one edge of the study area. Finally, subsoil was rearranged as necessary to create a level surface, resulting in more cut-and-fill and subsoil mixing at sites with steeper slopes. Glyphosate


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herbicide [560 g/acre (8 oz./acre)] was used during the 2008 growing season as necessary to control weeds on the pads. Topsoil piles at low elevation sites were broadcast seeded at in September at 12 PLS/acre with grasses listed in Table 1. Topsoil piles at high elevation sites were broadcast seeded in November with the forb mixture listed in Table 1 at 6 PLS/acre, San Luis Slender Wheatgrass (3 PLS/acre), Nodding Brome (2 PLS/acre), and Mountain Brome (2 PLS/acre).

RESULTS AND DISCUSSION Native species cover and downy brome cover varied widely among experiment 1 sites (Figures 3-8). The highest native species cover was 73%, measured at YC1, and the lowest native species cover was 25%, measured at SKH. The highest downy brome cover at any site was 68%, measured at SKH, and the lowest was 0%, measured at WRR (although downy brome was present near the site). WRR and YC1 both had the highest cover of native grasses (50%), and WRR had the highest cover of native forbs (11%). These data indicate that a wide range of pre-treatment site conditions was included in our sample of locations for experiment 1. Results of treatment effects at this time are extremely preliminary and likely to change with the further collection of data. Downy brome emergence times varied widely by study site, and there were 100-fold site-to-site differences in our measurements of seedling density in early November. Two of the sites (WRR and SKH) had control-plot seedling densities of less than 1 seedling per square meter. Control plot seedling densities at the other 4 sites were as follows [control plot means in seedlings/m2 (95% CI)]: GVM: 4.8 (2.0, 7.6); RYG: 919.8 (621.0, 1219.6); YC1: 5.1 (1.5, 8.7); and YC2: 83.0 (46.5, 119.5). The site-to-site differences in seedling density resulted in a highly significant treatment*site interaction, requiring analyses to be conducted separately by site. The analyses were restricted to only the four sites with sufficient seedling density for analysis (GVM, RYG, YC1, and YC2). Some effect of the herbicide treatment was apparent at 2 of the 4 sites. Seedling densities were lower with the herbicide treatment at RYG (97% lower, p < 0.0001) and GVM (55% lower, p = 0.03), but seedling densities were not different with the herbicide treatment at YC1 or YC2. The reason for this difference is unclear. Seedling densities at the YC2 site, if not also at YC1, were certainly sufficient for detecting treatment effects. The downy brome ecotype at the Yellow Creek sites may be more resistant herbicides, or the effects may simply take longer to become apparent at the drier Yellow Creek sites. Seedling densities were lower at some sites with the M, M2, and F soil treatments. Seedling density was lower with the M treatment at GVM (82% lower, p = 0.01) and RYG (81% lower, p = 0.002) but not at YC1 or YC2. Seedling density was lower with the M2 treatment at YC2 (49% lower, p = 0.01) but not at YC1. Seedling density was lower with the F treatment at RYG (81% lower, p = 0.004) and YC2 (49% lower, p = 0.01), but not at GVM or YC1. The two sites RYG and YC2 are also the two sites with the earliest downy brome emergence dates and highest November seedling densities. It may be that that action of tilling in the F treatment killed germinating seedlings at these, but not at other sites. Tilling action may also be responsible for some of the effectiveness of the M treatment, as these plots were also disked before being compacted. It should be noted that within plot variability in seedling density was very high. Some of the effects reported here may be coincidental due to variability in seedling emergence and seed availability, which could easily be influenced by wind direction and the manner in which stockpiled topsoil was respread across each site. With more time and opportunities for seedling emergence and seed dispersal, these confounding differences should diminish, and additional effects may become apparent. Even so, the fact that some soil treatments were effective at the sites with the highest November seedling densities, RYG and YC2, indicates that the use of soil


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manipulations to reduce downy brome impacts may be useful in oilfield restoration, provided that desirable native species are able to germinate and establish in the manipulated soil.

FUTURE WORK

Monitoring of experiment 1 will include measurements of soil compaction in order to test the longevity of the treatments applied. Soil compaction will be assessed in early spring of 2009 using a Jornada cone penetrometer (Herrick and Jones 2002) in 5 locations per plot to a depth of 60 cm. If measurements reveal that treatment differences are not detectable between control plots and light compaction plots, then a spring compaction treatment may be applied to the light compaction plots. Spring compaction is of interest because it has been shown to be more successful than fall compaction in controlling downy brome in winter wheat plantings (Singh et al. 1976). Monitoring of soil compaction in all plots will continue on a yearly basis throughout the duration of the experiment. Plant community development will be monitoring using seedling density counts of downy brome and other species in May and July of 2009. These measurements will be repeated in subsequent years until plant cover exceeds 20% of total ground cover, at which time point-intercept measurements of percent cover will be substituted for seedling counts. Monitoring of plant community development will continue, at minimum, through fall of 2010. Treatments for experiment 2 will be implemented in August of 2009. A soil manipulation and/or herbicide application treatment will be chosen after determining which treatments in experiment 1 yield the lowest spring downy brome seedling densities. In addition, a wind screen treatment may be implemented. This treatment would be designed to prevent additional seed inputs from arriving in the research area from the surrounding vegetation. Finally, a fencing treatment will be imposed which will compare the effects of wildlife-proof versus livestock-proof fencing. Research plots will be drill seeded using a native grass, forb, and shrub mixture. In contrast to experiment 1, however, seed mixes will be custom designed for each location, because planting the same seed mix over the large range of elevation and precipitation of experiment 2 sites would be unlikely to achieve desirable results. Monitoring of plant community development at experiment 2 sites will occur annually in July through 2014.

ACKNOWLEDGEMENTS This research has been funded by donations from Encana Oil and Gas (Encana), Shell Oil Company, and Williams Production Company (Williams). Land access was provided by Williams, Encana, ConocoPhillips, the Bureau of Land Management (BLM), and the Colorado Division of Wildlife (DOW). Logistical support was provided by Ed Hallowed (BLM), Ken Holsinger (BLM), Rob Raley (Williams), Mike Gardner (Williams), Mike Reynolds (Williams), Dan Colette (Williams), Nicole Byrnes (Encana), and Justin Lovato (ConocoPhillips). Steve Hanson (Brady Construction), Reed Wold (MB Construction), and Jon Maille (J3 Environmental) oversaw construction crews. Kim Kaal (DOW) organized funding efforts, and Brett Walker (DOW) and Chuck Anderson (DOW) provided research advice. Ruth Bennett and Andrew Paull collected field data.


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LITERATURE CITED

Avis, L. 1997. COGCC Piceance basin well site reclamation survey. Colorado

Department of Natural Resources. Baker, W. L., J. Garner, and P. Lyon. 2007. Effect Imazapic on Downy Brome (Bromus

tectorum) and Native Plants in Wyoming Big Sagebrush. Colorado Division of Wildlife.

Bekedam, S. 2004. Establishment tolerance of six native sagebursh steppe species to Imazapic (PLATEAU) herbicide: Implications for restoration and recovery. Oregon State University, Corvallis, OR.

Bergquist, E., P. Evangelista, T. J. Stohlgren, and N. Alley. 2007. Invasive species and coal bed methane development in the Powder River Basin, Wyoming. Environmental Monitoring and Assessment 128:381-394.

Christian, J. M., and S. D. Wilson. 1999. Long-term ecosystem impacts of an introduced grass in the northern Great Plains. Ecology 80:2397-2407.

Herrick, J. E., and T. L. Jones. 2002. A dynamic cone penetrometer for measuring soil penetration resistance. Soil Science Society of America Journal 66:1320-1324.

Herrick, J. E., J. W. Van Zee, K. M. Havstad, L. M. Burkett, and W. G. Whitford. 2005. Monitoring Manual for Grassland, Shrubland and Savanna Ecosystems Vol 1: Quick Start. Volume 1.USDA-ARS Jornada Experimental Range, Las Cruces, NM.

Krzic, M., K. Broersma, D. J. Thompson, and A. A. Bomke. 2000. Soil properties and species diversity of grazed crested wheatgrass and native rangelands. Journal of Range Management 53:353-358.

Kyle, G. P., K. H. Beard, and A. Kulmatiski. 2007. Reduced soil compaction enhances establishment of non-native plant species. Plant Ecology 193:223-232.

Kyser, G. B., J. M. DiTomaso, M. P. Doran, S. B. Orloff, R. G. Wilson, D. L. Lancaster, D. F. Lile, and M. L. Porath. 2007. Control of medusahead (Taeniatherum caput-medusae) and other annual grasses with imazapic. Weed Technology 21:66-75.

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igure 1. Research locations in Rio Blanco and Garfield Counties, Colorado, USA. The Yellow Creek

nd e

Research Locations for Experiments 1 and 2

Yellow Creek 2Yellow Creek 1

Ryan Gulch

Wagon Road Ridge

Square S

Sage 69 Rd

Mtn Shrub69 Rd

ScandardSnowpile

Girls’ Claims

Grand ValleyMesa

SK Holdings

MEEKER

RIFLE

F1, Yellow Creek 2, Ryan Gulch, Wagon Road Ridge, SK Holdings, and Grand Valley Mesa sites include plots for both experiment 1 (weed control techniques on simulated pipeline disturbances) aexperiment 2 (weed control, planting, and fencing techniques on simulated well pad disturbances). Thremainder of the sites includes plots only for experiment 2. The total range of elevation for all research sites is 1,115 m.


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Herbicide No Herbicide

Varying soil density

Figure 2. Experiment 1 is a split-plot experiment with 2 simulated pipeline strips, one of which receives herbicide, crossed with 5 soil manipulations with varying soil density within each strip.


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Grand Valley Mesa

Figure 3. The Grand Valley Mesa site (elevation 1662 m) was characterized by mature Wyoming big sagebrush and scattered Utah juniper (Juniperous Utahensis) with little herbaceous understory and a prevalence of crypto biotic crust. In the bar graph, juniper is included in the shrub category, and the bar for non-native grass represents exclusively downy brome. Percent cover values by plant type (bar chart) sum to a value greater than that of total plant cover (pie chart) due to overlap of plant canopies.


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SK Holdings

Figure 4. The SK Holdings site (elevation 1561 m) was characterized by an overstory of mature Wyoming big sagebrush and an understory dominated by downy brome. In the pie chart, the “OTHER” category is comprised of standing dead, rock, and crypto biotic crust. In the bar graph, the bar for non-native grass is comprised 99% of downy brome. Percent cover values by plant type (bar chart) sum to a value greater than that of total plant cover (pie chart) due to overlap of plant canopies.


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Wagon Road Ridge

Figure 5. The Wagon Road Ridge site (elevation 2216 m) was characterized by an overstory of Wyoming big sagebrush, serviceberry (Amelanchier alnifolia) and scattered Utah juniper, with a diverse understory of native forbs and grasses including sandberg bluegrass (Poa secunda), western wheatgrass (Agropyron smithii), and prairie junegrass (Koleria macrantha). Downy brome was present at the edge of the road 30m from the site, but none was detected at the site. Percent cover values by plant type (bar chart) sum to a value greater than that of total plant cover (pie chart) due to overlap of plant canopies.


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Ryan Gulch

Figure 6. The Ryan Gulch site (elevation 2084 m) was characterized by an overstory of Wyoming big sagebrush, rubber rabbitbrush (Chrysothamnus nauseosus), and yellow rabbitbrush (Chrysothamnus viscidiflorus), with an understory primarily of downy brome but also including slender wheatgrass (Elymus trachycaulus). In the bar graph, the bar for non-native grass is comprised 99% of downy brome. In the pie graph, the “OTHER” category includes bare ground, rock, and standing dead. Percent cover values by plant type (bar chart) sum to a value greater than that of total plant cover (pie chart) due to overlap of plant canopies.


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Yellow Creek 1

Figure 7. The Yellow Creek 1 site (elevation 1905 m) was characterized by an overstory of Wyoming big sagebrush and rubber rabbitbrush with a roughly equal, patchy mixture of downy brome and native grasses [primarily slender wheatgrass and needle-and-thread (Stipa comata)] in the understory. In the bar graph, the bar for non-native grass is comprised 100% of downy brome. Percent cover values by plant type (bar chart) sum to a value greater than that of total plant cover (pie chart) due to overlap of plant canopies.


Yellow Creek 2

Figure 8. The Yellow Creek 2 site (elevation 1829 m) was characterized by an overstory of mature Wyoming big sagebrush and rubber rabbitbrush and an understory of downy brome and the non-native forb desert alyssum (Alyssum desertorum). In the pie chart, the “OTHER” category is comprised of moss and crypto biotic crust. In the bar chart, the non-native grass bar is comprised 100% of downy brome. Percent cover values by plant type (bar chart) sum to a value greater than that of total plant cover (pie chart) due to overlap of plant canopies.

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COLORADO DIVISION OF WILDLIFE – AVIAN RESEARCH …€¦ · COLORADO DIVISION OF WILDLIFE – AVIAN RESEARCH PROGRAM ANNUAL PROGRESS REPORT February 3, 2009 TITLE: Restoring energy