Relationships Between Western Juniper (Juniperus occidentalis) and Understory Vegetation

D. E. Coultrap; K. O. Fulgham; D. L. Lancaster; J. Gustafson; D. F. Lile; M. R. George

doi:10.1614/ipsm-07-008.1

Relationships Between Western Juniper (Juniperus occidentalis) and Understory Vegetation

Invasive Plant Science and Management ◽

10.1614/ipsm-07-008.1 ◽

2008 ◽

Vol 1 (1) ◽

pp. 3-11 ◽

Cited By ~ 20

Author(s):

D. E. Coultrap ◽

K. O. Fulgham ◽

D. L. Lancaster ◽

J. Gustafson ◽

D. F. Lile ◽

...

Keyword(s):

Canopy Cover ◽

Understory Vegetation ◽

Sagebrush Steppe ◽

Grass Cover ◽

Bare Ground ◽

Western Juniper ◽

Steppe Communities ◽

Juniper Woodland ◽

Successional Stages ◽

The Impact

AbstractWestern juniper has been actively invading sagebrush plant communities for about 130 yr. Western juniper canopy cover generally increases as western juniper invades sagebrush steppe communities and succession progresses toward a western juniper woodland. Our goal was to estimate the impact of juniper invasion and canopy increase on understory vegetation structure and productivity on 101 sites in northeastern California. The primary objectives of this study were to: (1) examine the influence of increasing western juniper canopy cover on the composition and productivity of understory vegetation; and (2) assess the effects of western juniper removal on understory vegetation. Sites in early, mid-, and late successional stages and sites on the same soils that had not been invaded were selected. Sites where western juniper had been removed by prescribed fire, mechanical, or chemical methods were compared to adjacent untreated sites. Western juniper canopy cover, understory cover and species composition, productivity, and bare ground were determined at each site during May through July 2005 and 2006. Regression analysis was used to evaluate the relationship between western juniper canopy cover and understory vegetation parameters. Logistic regression was used to detect understory differences between treated (juniper removed) and untreated (juniper not removed) sites. A significant relationship was found between western juniper canopy cover and understory species richness, shrub cover, forb cover, total grass cover, cheatgrass cover, herbaceous productivity, and bare ground. Removal of western juniper increased total grass cover, cheatgrass cover, and productivity, and reduced bare ground. The results of this study support findings by researchers in other states that western juniper influences plant community structure and productivity, and removal of western juniper might reverse these changes in structure, but also might increase opportunities for invasion of cheatgrass.

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Overstory–Understory Vegetation Cover and Soil Water Content Observations in Western Juniper Woodlands: A Paired Watershed Study in Central Oregon, USA

Forests ◽

10.3390/f10020151 ◽

2019 ◽

Vol 10 (2) ◽

pp. 151 ◽

Cited By ~ 6

Author(s):

Grace Ray ◽

Carlos G. Ochoa ◽

Tim Deboodt ◽

Ricardo Mata-Gonzalez

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Texture ◽

Canopy Cover ◽

Understory Vegetation ◽

Watershed Scale ◽

Shrub Cover ◽

Western Juniper ◽

Tree Canopy Cover

The effects of western juniper (Juniperus occidentalis) control on understory vegetation and soil water content were studied at the watershed-scale. Seasonal differences in topsoil (12 cm) water content, as affected by vegetation structure and soil texture, were evaluated in a 96-ha untreated watershed and in a 116-ha watershed where 90% juniper was removed in 2005. A watershed-scale characterization of vegetation canopy cover and soil texture was completed to determine some of the potential driving factors influencing topsoil water content fluctuations throughout dry and wet seasons for approximately one year (2014–2015). We found greater perennial grass, annual grass, and shrub cover in the treated watershed. Forb cover was no different between watersheds, and as expected, tree canopy cover was greater in the untreated watershed. Results also show that on average, topsoil water content was 1% to 3% greater in the treated watershed. The exception was during one of the wettest months (March) evaluated, when soil water content in the untreated watershed exceeded that of the treated by <2%. It was noted that soil water content levels that accumulated in areas near valley bottoms and streams were greater in the treated watershed than in the untreated toward the end of the study in late spring. This is consistent with results obtained from a more recent study where we documented an increase in subsurface flow residence time in the treated watershed. Overall, even though average soil water content differences between watersheds were not starkly different, the fact that more herbaceous vegetation and shrub cover were found in the treated watershed led us to conclude that the long-term effects of juniper removal on soil water content redistribution throughout the landscape may be beneficial towards restoring important ecohydrologic connections in these semiarid ecosystems of central Oregon.

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Resource selection and space use ofMyotis evotisin a western juniper woodland in Oregon

Journal of Mammalogy ◽

10.1093/jmammal/gyy150 ◽

2018 ◽

Vol 100 (1) ◽

pp. 239-248

Author(s):

Christopher R Anthony ◽

Dana M Sanchez

Keyword(s):

Resource Selection ◽

Space Use ◽

Western Juniper ◽

Juniper Woodland

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The impact of the provision of water for game on the woody vegetation around a dam in the Kruger National Park

Koedoe ◽

10.4102/koedoe.v34i2.429 ◽

1991 ◽

Vol 34 (2) ◽

Cited By ~ 1

Author(s):

I. Thrash ◽

P.J. Nel ◽

G.K. Theron ◽

J. Du P. Bothma

Keyword(s):

Relative Density ◽

Woody Plants ◽

National Park ◽

Dominant Species ◽

Canopy Cover ◽

Kruger National Park ◽

Woody Vegetation ◽

Colophospermum Mopane ◽

The Impact ◽

Combretum Apiculatum

Quantitative inventory surveys were done on the woody vegetation in permanently marked plots at distance intervals from the Wik-en-Weeg Dam, Kruger National Park, in 1973. The surveys were repeated in 1990 so that changes in the community composition, the density and the canopy cover and the survival of the woody vegetation could be determined in relation to distance from the dam. Relationships with distance from the dam were shown for the relative density ofCombretumapiculatum in all height classes, the relative canopy cover of the second height class of woody plants, the relative canopy cover of C. apiculatum plants, the survival of all height classes of woody plants and the survival of C. apiculatum and Colophospermum mopane plants. It was concluded that the provision of water for game at the Wik-en-Weeg Dam had an impact on the woody vegetation in the vicinity. The relationships of parameters of the two dominant species, Combretum apiculatum and Colophospermum mopane, with distance from the dam were compared. Combretum apiculatum parameters were more sensitive to impact associated with the dam than those of Colophospermum mopane.

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Understory Vegetation Richness and Diversity of Eucalyptus benthamii and Pinus elliottii Plantations in the Midsouth US

Forest Science ◽

10.1093/forsci/fxz051 ◽

2019 ◽

Author(s):

Andrea De Stefano ◽

Michael A Blazier ◽

Christopher E Comer ◽

Thomas J Dean ◽

T Bently Wigley

Keyword(s):

United States ◽

Species Richness ◽

Soil Ph ◽

Pinus Elliottii ◽

The United States ◽

Slash Pine ◽

Understory Vegetation ◽

Understory Species ◽

Species Richness And Diversity ◽

The Impact

Abstract In the Western Gulf region of the United States cold-tolerant eucalyptus have been explored as pulpwood feedstock. However, non-native plantations may alter understory species diversity, modifying environmental conditions and soil characteristics. Few studies have compared eucalyptus plantations with native ecosystems to understand the impact on understory vegetation in the United States. In this study, we compared understory plant species richness and diversity during 2014–2016 in (1) slash pine (Pinus elliottii) established in 2008, (2) slash pine established in 2013, and (3) and Camden white gum (Eucalyptus benthamii) established in 2013. Overstory characteristics, soil pH, and soil nutrient concentrations were measured to understand factors that affected understory species richness and diversity. Results indicated a decline in understory species richness over time, with Camden white gum in an intermediate condition between same-age slash pine (highest richness) and older slash pine (lowest richness). Leaf area index, soil pH and K, and tree height were the most important factors influencing understory species richness and diversity. The adoption of fast-growing eucalyptus on these sites will probably accelerate the deterioration of natural habitats and reduce open-condition species in favor of shade-tolerant species, overturning the conservation efforts already put in place by governmental agencies and conservation groups.

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Occurrence and Dispersal of Indicator Bacteria on Cucumbers Grown Horizontally or Vertically on Various Mulch Types

Journal of Food Protection ◽

10.4315/0362-028x.jfp-16-106 ◽

2016 ◽

Vol 79 (10) ◽

pp. 1663-1672 ◽

Cited By ~ 4

Author(s):

SHIRLEY A. MICALLEF ◽

MARY THERESA CALLAHAN ◽

SIVARANJANI PAGADALA

Keyword(s):

Production System ◽

Production Systems ◽

Field Trials ◽

Dairy Manure ◽

Bare Ground ◽

Plastic Mulch ◽

Dispersal Patterns ◽

E Coli ◽

Thermotolerant Coliforms ◽

The Impact

ABSTRACT No data exist on the impact of cultivation practices on food safety risks associated with cucumber. Cucumbers are typically grown horizontally over a mulch cover, with fruit touching the ground, but this vining plant grows well in vertical systems. To assess whether production system affects bacterial dispersal onto plants, field trials were conducted over 2 years. Cucumber cultivar ‘Marketmore 76’ was grown horizontally on plastic, straw, or bare ground or vertically on trellises installed on bare ground in soil previously amended with raw dairy manure. Fruit, flower, leaf, and soil samples were collected to quantify Escherichia coli, thermotolerant coliforms, and enterococci by direct plating. E. coli isolates were characterized by BOX-PCR to evaluate relatedness among strains. Although thermotolerant coliforms and enterococci were significantly less abundant on fruit in year 1 (P < 0.05), this result was not seen in year 2 when more rain was recorded. Instead, fruit from straw-mulched beds had higher levels of enterococci compared with fruit grown on bare ground (P < 0.05). Leaves on bare ground occasionally had more bacteria than did leaves on plastic mulch beds (P < 0.05). Production system did not impact flower-associated bacterial levels. E. coli isolates (n =127) were genotyped, generating 21 distinct fingerprints. Vertical production did not appear to be a barrier for E. coli dispersal to the crop, as suggested by numerous related isolates from soil and flowers on bare ground, straw-mulched, and trellised beds (subcluster B1). None of the isolates from soil and flowers in this subcluster were related to isolates recovered from fruit, showing that flower colonization does not necessarily lead to fruit colonization. One cluster of isolates contained those from flowers and fruits but not soil, indicating a source other than manure-amended soil. Straw may be a source of E. coli; a number of closely related E. coli isolates were retrieved from soil and fruits from straw-mulched beds. Our approach revealed E. coli dispersal patterns and could be used to assess bacterial transmission in other production systems.

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A Systems Approach for the Management of Russian Knapweed (Centaurea repens)

Weed Technology ◽

10.1017/s0890037x00043943 ◽

1998 ◽

Vol 12 (2) ◽

pp. 363-366 ◽

Cited By ~ 15

Author(s):

Rick M. Bottoms ◽

Tom D. Whitson

Keyword(s):

Systems Approach ◽

Cultural Practices ◽

Canopy Cover ◽

Economic Feasibility ◽

Grass Species ◽

Grass Cover ◽

Russian Knapweed ◽

Centaurea Repens ◽

Significant Difference ◽

Russian Wildrye

Studies were initiated in Wyoming to determine the potential of grass competition as an alternative to repetitive herbicide treatment or other cultural practices for control of Russian knapweed. An experiment was established to evaluate the effects of five grass species, including Russian wildrye cv. ‘Bozoisky.’ Picloram, applied to Russian knapweed during the first frost, reduced Russian knapweed from an average of 80.1% live canopy cover which equates to 0% control. Untreated, unseeded checks resulted in 83.9 and 81.1% control in tilled and nontilled treated plots, respectively. Grass cover increased in untreated seeded plots from an average of 11.3 and 8.2% in tilled and nontilled plots, respectively, to 65% in tilled and 66% in nontilled plots treated with clopyralid plus 2,4-D. Grass cover also increased 69.7% in tilled and 66% in nontilled plots treated with picloram. There was no significant difference between grass varieties when compared to percent Russian knapweed cover. Reductions to zero live canopy cover of Russian knapweed were obtained with a single application of picloram. Economic feasibility thresholds were obtained from four out of five varieties, including a significant difference provided by nontilled Russian wildrye treated with picloram.

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Integrated Management of Cheatgrass (Bromus tectorum) with Sheep Grazing and Herbicide

Agronomy ◽

10.3390/agronomy9060315 ◽

2019 ◽

Vol 9 (6) ◽

pp. 315 ◽

Cited By ~ 2

Author(s):

Erik A. Lehnhoff ◽

Lisa J. Rew ◽

Jane M. Mangold ◽

Tim Seipel ◽

Devon Ragen

Keyword(s):

Bromus Tectorum ◽

Multiple Stressors ◽

Integrated Management ◽

Plant Cover ◽

Ground Surface ◽

Sagebrush Steppe ◽

Grass Cover ◽

Sheep Grazing ◽

Native Grass ◽

Targeted Grazing

Cheatgrass (Bromus tectorum L.) is one of the most problematic weeds in western United States rangelands and sagebrush steppe. It responds positively to different forms of disturbance, and its management has proven difficult. Herbicide or targeted grazing alone often fail to provide adequate long-term control. Integrating both may afford better control by providing multiple stressors to the weed. We assessed herbicide application, targeted sheep grazing and integrated herbicide and grazing on B. tectorum and the plant community in rangeland in southwestern Montana from 2015 until 2017. Herbicide treatments included spring-applied (May 2015 and 2016) glyphosate, fall-applied (October 2015) glyphosate, imazapic and rimsulfuron, and spring-applied glyphosate plus fall-applied imazapic. Targeted grazing, consisting of four sheep/0.01 ha for a day in 5 m × 20 m plots (all vegetation removed to the ground surface), occurred twice (May 2015 and 2016). While no treatments reduced B. tectorum biomass or seed production, grazing integrated with fall-applied imazapic or rimsulfuron reduced B. tectorum cover from approximately 26% to 14% in 2016 and from 33% to 16% in 2017, compared to ungrazed control plots, and by an even greater amount compared to these herbicides applied without grazing. By 2017, all treatments except spring-applied glyphosate increased total plant cover (excluding B. tectorum) by 8%–12% compared to the control plots, and forbs were generally responsible for this increase. Bromus tectorum management is difficult and our results point to a potential management paradox: Integrating grazing and fall-applied herbicide decreased B. tectorum cover but did not increase native grass cover, while some herbicides without grazing increased native grass cover, but failed to control B. tectorum. Additional research is necessary to determine grazing strategies that will complement herbicide control of B. tectorum while also stimulating native grass recovery, but this initial study demonstrates the potential of integrated management of B. tectorum compared to grazing or herbicide alone.

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The economic benefits of reductions in nitrogen loads from stormwater runoff by street trees

Blue-Green Systems ◽

10.2166/bgs.2020.006 ◽

2020 ◽

Author(s):

Mariana D. Baptista ◽

Marco Amati ◽

Tim D. Fletcher ◽

Matthew J. Burns

Keyword(s):

Stormwater Runoff ◽

Canopy Cover ◽

Annual Runoff ◽

Urban Trees ◽

Deciduous Trees ◽

Street Trees ◽

Runoff Volume ◽

Nitrogen Loads ◽

Tree Canopy Cover ◽

The Impact

Abstract It is increasingly recognised that urban trees can contribute to reducing stormwater runoff by intercepting and retaining a fraction of rainfall received. What is less studied is the translation of this to reduced pollutant loads being transferred to receiving streams, rivers, and water bodies. In this paper, we assess interception of two tree species (Eucalyptus microcorys and Ulmus procera) in an urban park. This data is used in simple water balance modelling to predict the environmental and economic benefit of reducing nitrogen loads to receiving waterways as a function of reduced runoff volume resulting from rainfall interception by urban trees on public land (21% of the catchment area). We use a highly urbanized catchment in Melbourne, Australia to demonstrate the impact of an urban forest dominated by deciduous trees, evergreen trees or a mixed tree canopy cover. We found that doubling the urban canopy cover in the catchment, while keeping the current mix ratio of deciduous and evergreen trees, could reduce annual runoff volume by 30 mm (92 MLyr−1). Using the prescribed values that developers must pay the local water authority for nitrogen treatment as a condition of new development, we calculate that this would deliver a nitrogen load removal benefit of AUD$ 200/tree. If only deciduous trees are planted the annual runoff reduction would decrease to 24 mm (73 MLyr−1) and increases to 37 mm (112 MLyr−1) if only evergreen trees are planted. This study highlights both the additional benefits of public street trees and the differences in deciduous and evergreen trees which should be accounted for by policy makers.

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Habitat Selection by 2 Closely Related Skinks, Egernia-Modesta Storr and Egernia-Whitii Lacepede (Lacertilia, Scincidae)

Wildlife Research ◽

10.1071/wr9860295 ◽

1986 ◽

Vol 13 (2) ◽

pp. 295 ◽

Cited By ~ 6

Author(s):

DA Milton ◽

JM Hughes

Keyword(s):

Habitat Selection ◽

Human Disturbance ◽

Habitat Preferences ◽

Canopy Cover ◽

Niche Separation ◽

Grass Cover ◽

Allopatric Populations ◽

Narrow Zone ◽

Current Distributions ◽

Microhabitat Preferences

'The habitat and microhabitat preferences, and times of activity, of the skinks Egernia modesta and E. whitii were examined in southern Queensland where they coexist in a narrow zone. The above parameters were compared between locally sympatric and allopatric populations, in an attempt to determine whether there was evidence of niche separation in sympatry. E. modesta preferred open habitats with little canopy cover and high grass cover, adjacent to rocky retreats. E. whitii preferred rocky areas with well developed canopy and shrub layers. Both species were active throughout the day, although E. modesta was active later than E. whitii. No evidence was found of competition restricting habitat preferences where the two species coexisted. It is suggested that human disturbance has had some influence on current distributions of these species.

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