Bunchgrass plant communities of the Blue and Ochoco Mountains: a guide for managers.

Johnson, Cathleen; Swanson, David K.

doi:10.2737/pnw-gtr-641

Cited by 22 publications

(39 citation statements)

References 30 publications

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“…Widespread impacts began in the 1870s with the expansion of cattle and sheep grazing, which then peaked by 1900 (Johnson and Swanson, 2005). Livestock numbers declined after 1906 as the Forest Service began to regulate grazing through the allotment system (Johnson and Swanson, 2005). In the last 30 years, livestock grazing has decreased slightly, but there has been a substantial increase in elk numbers with a decline in deer numbers (Wells et al, 2001) resulting in a net gain in animal unit months of herbivory.…”

Section: Study Areamentioning

confidence: 96%

“…Intensive grazing probably began in the 1700s with Native American horses. Widespread impacts began in the 1870s with the expansion of cattle and sheep grazing, which then peaked by 1900 (Johnson and Swanson, 2005). Livestock numbers declined after 1906 as the Forest Service began to regulate grazing through the allotment system (Johnson and Swanson, 2005).…”

Section: Study Areamentioning

confidence: 99%

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Modeling the effects of herbivores on the abundance of forest overstory states using a state-transition approach in the upper Grande Ronde River Basin, Oregon, USA

Vávra

Hemstrom

Wisdom

2007

Landscape and Urban Planning

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Section: Study Areamentioning

confidence: 96%

Section: Study Areamentioning

confidence: 99%

Modeling the effects of herbivores on the abundance of forest overstory states using a state-transition approach in the upper Grande Ronde River Basin, Oregon, USA

Vávra

Hemstrom

Wisdom

2007

Landscape and Urban Planning

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“…Early summer application of herbicides occurred in early May 2002 (Johnson and Swanson 2005). Seeding was done in late October 2002 and seeds were broadcast from the back of a four-wheel off-road vehicle that also trailed a harrow to increase soil-seed contact.…”

Section: Interpretive Summarymentioning

confidence: 99%

Herbicide and Native Grass Seeding Effects on Sulfur Cinquefoil (Potentilla Recta)-Infested Grasslands

Endress

Parks

Naylor

et al. 2008

Invasive plant sci. manag.

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Sulfur cinquefoil is an exotic, perennial forb that invades a wide range of ecosystems in western North America. It forms dense populations and often threatens native plant species and communities. In this study, we address the following questions: (1) what herbicides, rates, and application times are most effective at reducing sulfur cinquefoil abundance while having the least impact on native plants; and (2) does postherbicide seeding with native grass species increase native plant abundance? In 2002, we experimentally examined the effects of five herbicides (dicamba + 2,4-D; metsulfuron-methyl; triclopyr; glyphosate; and picloram) at two rates of application (low and high), three application times (early summer, fall, and a combined early summer–fall treatment), and two postherbicide seed addition treatments (seeded or not seeded) on sulfur cinquefoil abundance, plant community composition, and species richness. Experimental plots were monitored through 2005. Picloram was the most effective herbicide at reducing sulfur cinquefoil density, the proportion of remaining adult plants, and seed production. The effects of picloram continued to be evident after 3 yr, with 80% reduction of sulfur cinquefoil in 2005. In addition, seeding of native grass seeds alone (no herbicide application) reduced the proportion of sulfur cinquefoil plants that were reproductively active. Despite reductions in sulfur cinquefoil abundance, all treatments remained dominated by exotic species because treated areas transitioned from exotic forb- to exotic grass-dominated communities. However, a one-time herbicide application controlled sulfur cinquefoil for at least 3 yr, and therefore might provide a foundation to begin ecological restoration. Herbicide applications alone likely are to be insufficient for long-term sulfur cinquefoil control without further modification of sites through native grass or forb seeding. Integrating herbicides with native plant seeding to promote the development of plant communities that are resistant to sulfur cinquefoil invasion is a promising management approach to ecological restoration.

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“…Natural and anthropogenic disturbances have also shaped the canyon grassland vegetation over time in concert with topography (Tisdale ; Johnson ; Ecovista ; Cousins & Eriksson ; USDA Forest Service ). Historically, fire was frequent and heterogeneous across the landscape, causing very little change in species composition over time in response to this natural disturbance (Daubenmire ; Tisdale ; Johnson ; Gray & Lichthardt ; Johnson & Swanson ; Gucker & Bunting ). However, exotic species have altered plant community composition, and exotic annual grasses may have changed the natural fire regimes by allowing fires to become more intense and homogenous across the grasslands (Johnson ; Gray & Lichthardt ).…”

Section: Introductionmentioning

confidence: 99%

“…The classical concept of linear succession has evolved into state‐and‐transition models (Westoby et al. ; Johnson & Swanson ; USDA Forest Service ), but this original classification system provides a benchmark to examine the successional dynamics of these communities. Therefore, we first validated that the original classification of seral stages were different from one another in species composition in the original sampling year (1981) and in the resurvey (2014; Pack ).…”

Section: Introductionmentioning

confidence: 99%

Influence of topography on long‐term successional trajectories in canyon grasslands

Bernards¹,

Morris

2016

Applied Vegetation Science

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Question Some of the last remaining grassland communities of the Pacific Northwest Bunchgrass Region (PNWBR) in North America are found in canyon grasslands, primarily because the rugged topography has left many of these associations untouched by agricultural development. However, there have been no prior examinations into how canyon grassland communities change over the long term or how topography relates to these changes. In this study, we examined how successional stages changed over a 33‐yr time period and which topographical variables were most related to these long‐term outcomes (elevation, aspect or slope). We predicted that areas with more gentle slopes (<20%) would have changed the most because they have seen a higher concentration of historical land uses (e.g. livestock grazing, wildlife herbivory, and cultivation). Location Canyon grasslands of Hells Canyon National Recreation Area, northwest USA. Methods We looked at how the canyon grasslands have changed over the long term by repeating a vegetation survey of plant species cover and frequency that was completed in 1981 and comparing the results after a 33‐yr time period. Results We found that 58% of our plots stayed in the same seral stage or transitioned into later ones. As predicted, the plots that remained in early seral condition or transitioned from later to early seral stages were found on more shallow slopes. In addition, drier aspects within all plant associations appeared to be less resistant and resilient to change, particularly invasion by exotic species. Conclusions The results of this resurvey suggest that topographic patterns may not only be related to the distribution of plant associations across the canyon grasslands, but may also influence which sites change most over time. Our findings are consistent with other studies of the relationships between topography and land uses through time in other grasslands, and are highly relevant to conservation management where unique vegetation communities develop within heterogeneous topographic areas.

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Bunchgrass plant communities of the Blue and Ochoco Mountains: a guide for managers.

Cited by 22 publications

References 30 publications

Modeling the effects of herbivores on the abundance of forest overstory states using a state-transition approach in the upper Grande Ronde River Basin, Oregon, USA

Modeling the effects of herbivores on the abundance of forest overstory states using a state-transition approach in the upper Grande Ronde River Basin, Oregon, USA

Herbicide and Native Grass Seeding Effects on Sulfur Cinquefoil (Potentilla Recta)-Infested Grasslands

Influence of topography on long‐term successional trajectories in canyon grasslands

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