Resistance of Native Plant Functional Groups to Invasion by Medusahead (Taeniatherum caput-medusae)

2010 ◽  
Vol 3 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Roger L. Sheley ◽  
Jeremy James
Keyword(s):  
Functional Groups ◽  
Plant Communities ◽  
Perennial Grasses ◽  
Plant Functional Groups ◽  
Relative Importance ◽  
Native Plant ◽  
Big Sagebrush ◽  
Key Functional Groups ◽  
Wyoming Big Sagebrush ◽  
Density And Biomass

AbstractUnderstanding the relative importance of various functional groups in minimizing invasion by medusahead is central to increasing the resistance of native plant communities. The objective of this study was to determine the relative importance of key functional groups within an intact Wyoming big sagebrush–bluebunch wheatgrass community type on minimizing medusahead invasion. Treatments consisted of removal of seven functional groups at each of two sites, one with shrubs and one without shrubs. Removal treatments included (1) everything, (2) shrubs, (3) perennial grasses, (4) taprooted forbs, (5) rhizomatous forbs, (6) annual forbs, and (7) mosses. A control where nothing was removed was also established. Plots were arranged in a randomized complete block with 4 replications (blocks) at each site. Functional groups were removed beginning in the spring of 2004 and maintained monthly throughout each growing season through 2009. Medusahead was seeded at a rate of 2,000 seeds m−2 (186 seeds ft−2) in fall 2005. Removing perennial grasses nearly doubled medusahead density and biomass compared with any other removal treatment. The second highest density and biomass of medusahead occurred from removing rhizomatous forbs (phlox). We found perennial grasses played a relatively more significant role than other species in minimizing invasion by medusahead. We suggest that the most effective basis for establishing medusahead-resistant plant communities is to establish 2 or 3 highly productive grasses that are complementary in niche and that overlap that of the invading species.

Relative importance of protozoan functional groups in three marine sublittoral areas

2001 ◽  
Vol 81 (5) ◽  
pp. 735-750 ◽  
Author(s):  
Gregorio Fernandez-Leborans
Keyword(s):  
Functional Groups ◽  
Bacterial Biomass ◽  
Relative Importance ◽  
Significant Group ◽  
Important Group ◽  
Mean Grain Size ◽  
Marine Areas ◽  
Density And Biomass ◽  
Protozoan Species ◽  
Significant Factors

The composition in terms of protozoan functional groups of three sublittoral areas (Castro Urdiales, Santoña and Isla) in the Cantabrian Sea was analysed. The different protozoan species were identified, and their density and biomass was measured. The pigmented protozoa were the most important group in the three areas throughout the year, followed by the bacterivores in Castro Urdiales and Santoña, and the non-selectives in Isla. Bacterivores constituted the most significant group in terms of biomass, after which came that of non-selectives. The parameters with the strongest influence on distribution in functional groups (respect to biomass) were pH, phosphate, organic matter and bacterial biomass, other significant factors being salinity, nitrate and mean grain size. Functional groups expressed as number of species were affected principally by phosphate, pH and, to a lesser extent, temperature and salinity. Statistical analysis using the present data, data regarding functional groups from previous studies in the same areas, and data from other areas, indicate that marine areas show similar characteristics. In the areas covered by the present study, there was a decrease in the number of algivore species and a rise in non-selective species, while bacterivores and pigmented protozoa maintained similar values. In comparison, freshwater areas showed noticeably lower percentages of algivore species and a significantly higher number of bacterivore species.

Canopy Growth and Density of Wyoming Big Sagebrush Sown with Cool-Season Perennial Grasses

2006 ◽  
Vol 20 (3) ◽  
pp. 183-194 ◽  
Author(s):  
Ann L. Hild ◽  
Gerald E. Schuman ◽  
Laurel E. Vicklund ◽  
Mary I. Williams
Keyword(s):  
Perennial Grasses ◽  
Cool Season ◽  
Big Sagebrush ◽  
Wyoming Big Sagebrush

scholarly journals Effects of Continuous Slope Gradient on the Dominance Characteristics of Plant Functional Groups and Plant Diversity in Alpine Meadows

2018 ◽  
Vol 10 (12) ◽  
pp. 4805 ◽  
Author(s):  
Qi-Peng Zhang ◽  
Jian Wang ◽  
Hong-Liang Gu ◽  
Zhi-Gang Zhang ◽  
Qian Wang
Keyword(s):  
Water Content ◽  
Functional Groups ◽  
Plant Communities ◽  
Plant Diversity ◽  
Ph Value ◽  
Pearson Correlation ◽  
Plant Functional Groups ◽  
The Tibetan Plateau ◽  
Slope Gradient ◽  
Alpine Meadows

Many studies reported the effect on plant functional groups and plant diversity under discontinuous slope gradient. However, studies on the effect of continuous slope gradient on plant functional groups and plant diversity in alpine meadows have rarely been conducted. We studied the effect of a continuous slope gradient on the dominance characteristics of plant functional groups and plant diversity of alpine meadows on the Tibetan plateau—in Hezuo area of Gannan Tibetan Autonomous Prefecture. Altogether, 84 samples of alpine meadows grass and 84 soil samples from seven slope gradients at sunlit slopes were collected. By using analysis of variance (ANOVA) and Pearson correlation coefficient, this study revealed: (1) Continuous slope gradient is an important factor affecting plant communities in alpine meadows, due to the physical and chemical characteristics of the soil and water content. The number of families, genera, and species increased first then decreased at the different slope gradient levels, respectively; (2) there is a close relationship between the soil and plant functional groups, and plant diversity. In other words, the slope determines the functional groups of plants and the soil nutrients; and (3) soil characteristics (pH value, Soil Total Nitrogen, Soil Water Content) are the determining factors of the plant community characteristics at each slope gradient level. To conclude, a continuous slope gradient is an important factor that affects plant communities in alpine meadows.

scholarly journals Mid-term changes in the physiognomy of plant communities and functional plant groups define successional pathways of mountain vegetation in the province of Córdoba (Argentina)

2021 ◽  
Vol 48 (1) ◽  
pp. 9-24
Author(s):  
Marcos Sebastián Karlin ◽  
Sebastián Abel Arnulphi ◽  
Javier Rodolfo Bernasconi Salazar
Keyword(s):  
Functional Groups ◽  
Plant Communities ◽  
Life Forms ◽  
Plant Functional Groups ◽  
Plant Interactions ◽  
Two Phase ◽  
Plant Groups ◽  
Restoration Strategies ◽  
Mountain Vegetation ◽  
Successional Pathways

Abstract To identify restoration strategies over degraded semi-natural plant communities, successional pathways and their local controls should be identified. The objective of this work is to quantify the changes in the physiognomy and functional groups of plant communities in the Sierras Chicas of Córdoba along seven years. Lyapunov coefficients were calculated and arranged in two-phase diagrams, identifying different successional pathways over two soil categories and six plant communities. Du Rietz`s life forms were identified defining several plant functional groups. Results showed two successional pathways in the field of azonal soils and three in the field of intrazonal soils. Rainfall, extent of human-caused disturbances, and plant interactions are the leading causes explaining the changes in the structure of the plant communities. Fire and overgrazing retract the successions by altering the cover of plant communities and their functional groups.

Invasion of Medusahead into the Great Basin

Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 89-97 ◽  
Author(s):  
James A. Young ◽  
Raymond A. Evans
Keyword(s):  
Great Basin ◽  
Plant Communities ◽  
Coniferous Forest ◽  
Clay Soils ◽  
Native Plant ◽  
Big Sagebrush ◽  
Forest Sites ◽  
Environmental Unit ◽  
Woodland Communities ◽  
High Elevations

We characterized soil and vegetation assemblages, many of which are infested with medusahead (Taeniatherum asperum(Sim.) Nevski), on the margin of the Great Basin. Interpretations of these assemblages provide an index of the validity of the basic environmental unit of this ecosystem which can be manipulated through weed control and revegetation techniques. Vertisol (churning clay soils) sites with sparse native plant communities are more susceptible to medusahead invasion than more complex low sagebrush (Artemisia arbusculaNutt.) or low sagebrush-woodland communities on related clay soils. If the more complex communities are degraded to a low seral state, medusahead can invade and occupy the site. Wet meadows and burned coniferous forest sites at high elevations were the only sites where medusahead occurred on soils with textures other than clay. Big sagebrush (Artemisia tridentataNutt.) communities on medium to coarse textured soils were very resistant to medusahead invasion. The restriction of medusahead to certain sites controls the mechanism of invasion and interacts with the breeding system of the species to influence its evolution.

Effects of Using Winter Grazing as a Fuel Treatment on Wyoming Big Sagebrush Plant Communities

2016 ◽  
Vol 69 (3) ◽  
pp. 179-184 ◽  
Author(s):  
K.W. Davies ◽  
A.M. Nafus ◽  
C.S. Boyd ◽  
A. Hulet ◽  
J.D. Bates
Keyword(s):  
Plant Communities ◽  
Fuel Treatment ◽  
Big Sagebrush ◽  
Winter Grazing ◽  
Wyoming Big Sagebrush

scholarly journals Extending vegetation site data and ensemble models to predict patterns of foliage cover and species richness for plant functional groups

2021 ◽  
Vol 36 (5) ◽  
pp. 1391-1407
Author(s):  
Megan J. McNellie ◽  
Ian Oliver ◽  
Simon Ferrier ◽  
Graeme Newell ◽  
Glenn Manion ◽  
...  
Keyword(s):  
Species Richness ◽  
Functional Groups ◽  
Spatial Scales ◽  
Landscape Scale ◽  
Plant Functional Groups ◽  
Spatially Explicit ◽  
Native Plant ◽  
Environmental Predictors ◽  
Neural Network Models ◽  
Model Residuals

Abstract Context Ensembles of artificial neural network models can be trained to predict the continuous characteristics of vegetation such as the foliage cover and species richness of different plant functional groups. Objectives Our first objective was to synthesise existing site-based observations of native plant species to quantify summed percentage foliage cover and species richness within four functional groups and in totality. Secondly, we generated spatially-explicit, continuous, landscape-scale models of these functional groups, accompanied by maps of the model residuals to show uncertainty. Methods Using a case study from New South Wales, Australia, we aggregated floristic observations from 6806 sites into four common plant growth forms (trees, shrubs, grasses and forbs) representing four different functional groups. We coupled these response data with spatially-complete surfaces describing environmental predictors and predictors that reflect landscape-scale disturbance. We predicted the distribution of foliage cover and species richness of these four plant functional groups over 1.5 million hectares. Importantly, we display spatially explicit model residuals so that end-users have a tangible and transparent means of assessing model uncertainty. Results Models of richness generally performed well (R2 0.43–0.63), whereas models of cover were more variable (R2 0.12–0.69). RMSD ranged from 1.42 (tree richness) to 29.86 (total native cover). MAE ranged from 1.0 (tree richness) to 20.73 (total native foliage cover). Conclusions Continuous maps of vegetation attributes can add considerable value to existing maps and models of discrete vegetation classes and provide ecologically informative data to support better decisions across multiple spatial scales.

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