Mountain Big Sagebrush (Artemisia Tridentata Ssp Vaseyana) Seed Production PDF Download
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Author: Melissa L. Landeen Publisher: ISBN: Category : Languages : en Pages : 72
Book Description
Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure seed production on 13 sites ranging from 10-33 years post-fire. We hypothesized that seed rain (mean seeds produced/ m2) would peak before stand density had maximized due to decreasing individual plant fecundity (mean seeds produced/ plant) in high density stands. We measured population density and individual plant fecundity for three size classes of MBS and used forward stepwise regression analysis to identify environmental factors influencing seed production over time. Density for small (basal stem diameter 1 cm) and medium-sized (basal stem diameter=1-3 cm) plants was consistently low and was not affected by time since fire (TSF), while large-sized (basal stem diameter 3 cm) plant density increased steadily with TSF (p=0.0002). Plant fecundity decreased with TSF for all three size classes (p range = 0.019 – 0.0506), with large plants dominating reproductive output. Small and medium-sized plant fecundity was negatively correlated with winter precipitation (p range = 0.0106-0.0174), while large plant fecundity was positively correlated with winter precipitation (p
Author: Melissa L. Landeen Publisher: ISBN: Category : Languages : en Pages : 72
Book Description
Big sagebrush (Artemisia tridentata Nutt.) is the most widespread and common shrub in the sagebrush biome of western North America. Of the three most common subspecies of big sagebrush (Artemisia tridentata), mountain big sagebrush (ssp. vaseyana; MBS) is the most resilient to disturbance, but still requires favorable climactic conditions and a viable post-fire seedbank for successful unassisted recovery. This study was designed to assess MBS seed production throughout post-fire recovery. We performed 2 pilot studies to develop methods for estimating seed production and plant age. The results of the pilot studies and a space-for-time substitution strategy were used to measure seed production on 13 sites ranging from 10-33 years post-fire. We hypothesized that seed rain (mean seeds produced/ m2) would peak before stand density had maximized due to decreasing individual plant fecundity (mean seeds produced/ plant) in high density stands. We measured population density and individual plant fecundity for three size classes of MBS and used forward stepwise regression analysis to identify environmental factors influencing seed production over time. Density for small (basal stem diameter 1 cm) and medium-sized (basal stem diameter=1-3 cm) plants was consistently low and was not affected by time since fire (TSF), while large-sized (basal stem diameter 3 cm) plant density increased steadily with TSF (p=0.0002). Plant fecundity decreased with TSF for all three size classes (p range = 0.019 – 0.0506), with large plants dominating reproductive output. Small and medium-sized plant fecundity was negatively correlated with winter precipitation (p range = 0.0106-0.0174), while large plant fecundity was positively correlated with winter precipitation (p
Author: Bruce Leigh Welch Publisher: ISBN: Category : Big sagebrush Languages : en Pages : 220
Book Description
Pioneers traveling along the Oregon Trail from western Nebraska, through Wyoming and southern Idaho and into eastern Oregon, referred to their travel as an 800 mile journey through a sea of sagebrush, mainly big sagebrush ( Artemisia tridentata). Today approximately 50 percent of the sagebrush sea has given way to agriculture, cities and towns, and other human developments. What remains is further fragmented by range management practices, creeping expansion of woodlands, alien weed species, and the historic view that big sagebrush is a worthless plant. Two ideas are promoted in this report: (1) big sagebrush is a nursing mother to a host of organisms that range from microscopic fungi to large mammals, and (2) many range management practices applied to big sagebrush ecosystems are not science based.
Author: Bruce Leigh Welch Publisher: ISBN: Category : Big sagebrush Languages : en Pages : 38
Book Description
This paper examines the scientific merits of eight axioms of range or vegetative management pertaining to big sagebrush. These axioms are: (1) Wyoming big sagebrush (Artemisia tridentata ssp.wyomingensis) does not naturally exceed 10 percent canopy cover and mountain big sagebrush (A.t.ssp.vaseyana) does not naturally exceed 20 percent canopy cover; (2) As big sagebrush canopy cover increases over 12 to15 percent, bare ground increases and perennial grass cover decreases; (3) Removing, controlling, or killing big sagebrush will results in a two or three or more fold increase in perennial grass production; (4) Nothing eats it; (5) Biodiversity increases with removing, controlling, thinning, or killing of big sagebrush; (6) Mountain big sagebrush evolved in an environment with a mean fire interval of 20 to 30 years; (7) Big sagebrush is an agent of allelopathy; and (8) Big sagebrush is a highly competitive, dominating, suppressive plant species.
Author: Katherine M. DiCristina Publisher: ISBN: Category : Big sagebrush Languages : en Pages : 94
Book Description
In the growing season of 2003, patterns of establishment of Artemisia tridentata ssp. vaseyana were observed after fire in a sagebrush steppe ecosystem in southeastern Idaho. It was examined how A. t. vaseyana seedling establishment was affected by neighboring vegetation and how these effects were modulated by 1) identity (functional group) and proximity of neighboring vegetation, 2) time since burning, and 3) water availability. Manipulative experiments were conducted to further isolate how identity and water affect competitive interactions between seedlings and neighbors and so that the causal relationships between herbs and seedlings could be better substantiated. Patterns of establishment for A. t. vaseyana were detected in addition to interactions between A. t. vaseyana and neighboring herbs that appeared to be modulated by water. Therefore, in the growing season of 2004, it was observed how neighboring herbs and seasonal soil drying affected carbon assimilation and competitive responses of A. t. vaseyana seedlings. This research contributes to land management decisions in sagebrush steppe ecosystems.
Author: Melissa L. Landeen
Author: Melissa L. Landeen
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Author: Bruce Leigh Welch
Author: Bruce Leigh Welch
Author: Katherine M. DiCristina
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