Donald R. Kirby

An index of plant community integrity: development of the methodology for assessing prairie wetland plant communities

Abstract We developed an Index of Plant Community Integrity (IPCI) for quantitatively assessing the quality of seasonal wetland plant communities. In 1998 and 1999, we sampled the plant communities of 46 seasonal wetlands in the Prairie Pothole Region (PPR) of central North Dakota, USA. We selected wetlands that represented a range of disturbance from well-managed native rangeland to heavily disturbed cropland. We delineated plant data into metrics of the data set (e.g. species richness, percentage of introduced and annual plants) and analyzed these metrics using principal components (PCs) and cluster analyses. Through analyses, five quality classes (Very good, Good, Fair, Poor, and Very poor) were determined. We then assigned ranges and scores for each metric based on the statistical analyses. By using this classification system, the plant communities of additional seasonal wetlands in the PPR can now be assessed and placed in quality classes for mitigation or ecological purposes, such as tracking the improvement of restored or reclaimed wetlands, wildlife habitat evaluation, hydrogeomorphic (HGM) assessment, and evaluation of other ecological functions.

Biological control of leafy spurge with introduced flea beetles (Aphthona spp.)

Astract Flea beetles ( Aphthona spp.) were introduced into leafy spurge (E u p h o r b i a e s u l a L.)-infested rangeland in east-central North Dakota. The study objectives were to evaluate the effects of the introduced insects on leafy spurge cover, density, and yield, and grass and grass-like yield of associated plant communities. A p h t h o n a spp. were released in 1988 and 1989 at 2 sites near Valley City, N.D. Aboveground vegetative sampling for leafy spurge cover, density and yield, and grass and grass-like yield was conducted between 1993 and 1995. Belowground sampling of root density, dry weight and root buds was conducted between the release date and 1995. A p h t h o n a spp. reduced aboveground cover, density and yield of leafy spurge and increased yield of grass and grass-like species. Leafy spurge root density, weight, and number of root buds decreased on insect release sites between release dates and 1995. Reduced stem density of leafy spurge and increased grass and grass-like yield, should enhance cattle use and production from these sites.

Leafy spurge (Euphorbia esula) control with Aphthona spp. affects seedbank composition and native grass reestablishment.

Abstract Aphthona spp. flea beetles have established and reduced the density of leafy spurge in much of the western United States. One way to measure the long-term impact and effectiveness of a weed control program is by monitoring the changes in the seedbank over time. The change in leafy spurge stem density and seed in the seedbank were evaluated 5 yr after Aphthona spp. were released to control this weed in the Little Missouri National Grasslands in southwestern North Dakota. Leafy spurge density and seed in both loamy overflow and loamy ecological sites decreased, whereas desirable (high-seral) forbs increased 5 yr after the biological control agents were released. Leafy spurge topgrowth was reduced from an average of over 200 stems/m2 to less than 8 stems/m2 in the most densely infested sites, and leafy spurge seed was reduced from an average of 68% of the seedbank to only 14% in both ecological sites. High-seral forb seed increased by over 300% in the seedbank, which indicated the floristic quality of the sites, was returning to a preinfestation state. Species with the largest increase included western rock jasmine and fringed sage, which increased at least three-fold in both sites. Less desirable low-seral forbs and grasses accounted for about 30% of the seedbank. In a greenhouse study, native grass production was reduced nearly 50% when grown in soil from Aphthona spp. release sites compared to nonrelease sites. Switchgrass production was reduced to a greater extent (66%) than green needlegrass, little bluestem, or western wheatgrass. The cause and extent of reduced native grass production in sites where Aphthona spp. were released has yet to be determined. The decrease in leafy spurge topgrowth and seed in the soil seedbank as desirable species seed increased, should lead to the long-term recovery of the plant community. Nomenclature: Leafy spurge, Euphorbia esula L. EPHES; fringed sage, Artemisia frigida Willd; green needlegrass, Nassella viridula (Trin.) Barkworth; little bluestem, Schizachyrium scoparium (Michx.) Nash-Gould; switchgrass, Panicum virgatum L.; western rock jasmine, Androsace occidentalis Pursh; western wheatgrass, Pascopyrum smithii (Rydb.) A. Löve.

Leafy Spurge Suppression by Flea Beetles in The Little Missouri Drainage Basin, USA

Abstract The Ecological Area-wide Management Leafy Spurge, or TEAM Leafy Spurge, began collecting and redistributing flea beetles (Aphthona spp.) to research/demonstration sites and landowners throughout the Little Missouri River drainage basin to control leafy spurge in 1998. A study to evaluate the change over time of leafy spurge (Euphorbia esula L.) phytosociological characteristics following release of flea beetles was initiated in 2002 on leafy spurge–infested pasture and rangeland in the Little Missouri River drainage of Montana, North Dakota, South Dakota, and Wyoming. A total of 292 flea beetle release sites were analyzed in June and July 2002 and 2003 for leafy spurge stem density, foliar cover, flea beetle density, and vegetation composition. Leafy spurge stem density suppression was evident at 91% of the study sites. On two-thirds of the study sites stem density was reduced from greater than 100 stems·m−1 to less than 25 stems·m−1. Leafy spurge foliar cover was less than 5% on approximately two-thirds of the flea beetle release sites and less than 25% on over 90% of the release sites. Area of observed leafy spurge suppression ranged from 0 m2 to 30000 m2. Approximately 40% of the release sites had leafy spurge suppression ranging from 1000 m2 to 5000 m2, and 14% of the release sites had greater than 10000 m2 of leafy spurge control. Plant community composition following leafy spurge suppression was characteristic of native plant communities that had not been burned or grazed. Flea beetles effectively reduced leafy spurge stem density and cover in 4–5 yr across a variety of locations and corresponding environmental conditions, both within the Little Missouri River drainage and in selected nearby locations.

Integrated Leafy Spurge (Euphorbia esula) Control Using Imazapic, Aphthona spp. Biological Control Agents, and Seeded Native Grasses

Abstract Chemical, cultural, and biological methods have been developed to control leafy spurge in a variety of environments. Aphthona spp. biological control agents have established throughout the northern Great Plains and Rocky Mountain region and successfully controlled leafy spurge in many areas, but notable exceptions include areas with sandy soils. Leafy spurge control can be improved by combining methods such as chemical, biological, or cultural treatments, compared to a single method used alone. The effects of Aphthona spp., imazapic herbicide, and interseeded native grass species alone or in combination for leafy spurge control were evaluated at two locations in southeastern North Dakota for 5 yr. Both the Sheyenne National Grassland (SNG) and Walcott, ND, study locations had greater than 80% sand soil. Leafy spurge stem density, canopy cover, and yield were reduced for 1 to 2 yr in all treatments that included imazapic, with no difference in control between single and combination treatments. Aphthona spp. and interseeded native grasses alone or combined did not reduce leafy spurge density or cover. Aphthona spp. population remained low throughout the study at both locations. Forb yield increased during the study at the SNG but not the Walcott location. Conversely, warm-season grass yield increased at Walcott but not at the SNG. Leafy spurge stem density declined from 92 to 50 stems/m2 in 5 yr at the SNG site. The decline could not be attributed to specific treatments applied in this study and may be due to self-limitation or soil pathogens. Nomenclature: Imazapic ; leafy spurge, Euphorbia esula L. EPHES.

Evaluation of Restored and Native Prairie Pothole Region Plant Communities Following an Environmental Gradient

ABSTRACT: Historically, wetland and grassland ecosystems throughout the Prairie Pothole Region (PPR) of North America were shaped by fire, grazing, and alternating drought and deluge conditions. These historic disturbance patterns of the PPR have been altered by human modifications to the landscape. In recent years, managers have attempted to implement practices that simulate historic disturbance patterns in order to improve the diversity of structure and function in impacted ecosystems. This study evaluated the characteristics of restored and native wetland/grassland plant communities located within two National Wildlife Refuges (NWR) in the PPR of North Dakota. An extensive analysis of plant community composition following an environmental gradient was conducted in order to relate the composition and quality of wetland communities to the condition of adjacent upland grasslands and to compare the composition and quality of native and restored sites. Plant communities were evaluated using quadrat and transect methods and a Floristic Quality Index (FQI). Statistical analyses employed Nonmetric Multidimensional Scaling ordination and Multi-Response Permutation Procedure. We found wide variability in the composition and quality of the plant communities evaluated. Native plant communities were generally of higher quality than restored communities; also, plant communities located at Lostwood NWR generally contained more native components than those located at Tewaukon NWR. The results of this study show that restoration efforts, when properly managed, have the potential to improve the composition and quality of wetland and grassland plant communities. It is likely that the quality of the restored plant communities evaluated in this study will continue to improve with time and sustained management.

Controlling Kentucky Bluegrass with Herbicide and Burning Is Influenced by Invasion Level

Kentucky bluegrass (Poa pratensis L.) invades northern Great Plains rangelands. On the Sheyenne National Grassland in southeastern North Dakota, three research sites, each with a different level of Kentucky bluegrass invasion, were chosen to evaluate effectiveness of burning and burning—herbicide combinations to control Kentucky bluegrass. Initial Kentucky bluegrass invasion levels were 37%, 77%, and 91% for LOW, MODERATE, and HIGH invaded sites, respectively. Within each invaded site, four replicated strips (20 by 60 m) were established, with half of each strip burned in late October 2005 and the other half burned in early May 2006. Herbicide treatments of (1) no herbicide, (2) 2.24 kg ha-1 of glyphosate, and (3) 0.43 kg ha-1 of imazapic were randomly assigned to 10 by 20 m subplots within each burn. Control plots were established at the same time. Relative basal cover of native grass, native forb, and Kentucky bluegrass was estimated annually using 50 10-point frames within each subplot. On the HIGH site in 2006, fall-burned plots with a spring glyphosate application had three times the native grass cover and only one fourth of the Kentucky bluegrass cover compared with controls. Similar results with the same treatment occurred at the MODERATE site. Native grasses became the most abundant plant community on these plots in the MODERATE and HIGH sites within 1 yr. Treatment differences were transitory, and the LOW site differed from the MODERATE and HIGH sites. In 2007, on fall-burned plots with spring glyphosate application, the amount of Kentucky bluegrass was 14% and 30%, and native grass species were 52% and 42% on the MODERATE and HIGH sites, respectively, which was similar to the initial values on the LOW site. These data emphasize the importance of initial invasion level in developing restoration strategies and provide evidence burning and herbicide combinations can be valuable management tools even on heavily invaded grasslands. Nomenclature: Glyphosate; imazapic; Kentucky bluegrass, Poa pratensis L. POAPR.

Breeding Bird Selection of Restored and Native Wooded Draws in North Dakota

Breeding Bird Selection of Restored and Native Wooded Draws in North Dakota DOI:10.2458/azu_rangelands_v31i6_kelly

BREEDING BIRD SURVEY OF RECLAIMED AND NATIVE WOODLANDS IN NORTH DAKOTA

Woodlands comprise only about 1% of the landscape of the northern plains and provide valuable habitat for wildlife including breeding birds. Surveys were conducted between 1986 and 2000 for breeding birds on a native and a reclaimed woodland to evaluate the potential of mitigated woodlands lost to surface coal mining operations as replacement for native woodlands. Vegetation characteristics such as species composition and density, canopy cover, structure, amount of edge and ground cover were evaluated. Breeding bird surveys were conducted from mid-May through mid-June using the spot-mapping method. The native woodland had greater plant species diversity, stem density, canopy cover and height structure than the 18 year old reclaimed woodland. Both woodlands had a similar amount of edge of habitat. Breeding bird densities were higher in the native woodland throughout the study period 1986 to 2000. Species richness was higher 12 of 13 sampled years in the native woodland. Trend in density and species richness of breeding birds on the reclaimed woodland was higher throughout the study. Given sufficient time the reclaimed woodland may perform similar functions to native woodlands. Additional

Effects of Grazing on Diversity and Seasonal Balance of Reclaimed Grasslands in North Dakota

The purpose of this study was to evaluate the influence of prescribed seasonal grazing on diversity and seasonal balance of 2-yr old, 3-yr old and 4-yr old reclaimed grasslands in western North Dakota. Research was conducted on the Glenharold Mine in Oliver County, which is located in the Missouri Slope Physiographic Region of North Dakota. The 55 ha study area was comprised of adjoining 22, 24, and 9 ha areas reclaimed in 1994, 1995, and 1996, respectively. The seed mixture used contained 71 to 77% warm-season grasses. Grazing by 20 cow/calf pairs was implemented on the 55 ha site from May 26 to August 1, 1998 utilizing approximately 50% of aboveground biomass. In 1999 and 2000, grazing was conducted by 30 cow/calf pairs from May 8 to July 29 and May 7 to July 29, respectively. In 2001 and 2002, grazing by 45 cow/calf pairs was deferred until midJuly (July 15 to October 16) in efforts to maintain green needlegrass (Stipa viridula), a declining species on each site. Each site was randomly sampled for basal cover and species composition using a 10-pin point-frame. Alpha (intra-community) diversity fluctuated between sites early in the study; however, diversity trended higher on reclaimed sites in the last two years of the study. Total basal cover throughout the five year study ranged from 3.65 to 7.20%, 4.00 to 8.60% and 4.90 to 9.30% for the 1994, 1995 and 1996 reclaimed grasslands, respectively. Herbaceous biomass was estimated from 0.25 m quadrats by clipping at ground level, separating by grass species, forbs, and shrubs, and drying and weighing samples. Yields on reclaimed sites were highest in the early stages of research when compared to the reference site but trended similar in later stages. Seasonal balance of cooland warm-season grasses on the 1994, 1995 and 1996 reclaimed grasslands shifted from 73:27, 70:30 and 28:72 in 1998 to 65:35, 24:76 and 38:62 in 2002, respectively. Additional