Three C4 graminoids, Kyllinga nervosa, Themeda triandra, and Hyparrhenia filipendula, were grown ... more Three C4 graminoids, Kyllinga nervosa, Themeda triandra, and Hyparrhenia filipendula, were grown in unbalanced factorial treatment designs of clipping height, clipping frequency, watering frequency, and ni-trogen availability for periods equivalent to one growing season, after ...
... Three uncommon plant species (aspen, willow, and Wyoming big sagebrush Artemisia tridentata .... more ... Three uncommon plant species (aspen, willow, and Wyoming big sagebrush Artemisia tridentata ... assessment ungulates management native natural regulations. Francis J Singer, David M Swift ... Richard S Inouye, Nancy Huntly, G Wayne Minshall, JE Anderson in Biogeochemistry ...
Background/Question/Methods Cheatgrass (Bromus tectorum) is one of the most prolific invaders of ... more Background/Question/Methods Cheatgrass (Bromus tectorum) is one of the most prolific invaders of western rangelands, increasing fire frequency, decreasing wildlife and livestock habitat value and limiting the use of prescribed fire as a management tool. Once cheatgrass becomes established, it modifies the environment to create an ecologically stable state that is resilient to both successional processes and management intervention. The objective of the study reported here is to evaluate landscape scale constraints on conversion of perennial grass/shrublands to cheatgrass dominated stable states. Study sites were located in southeastern Wyoming and stratified by aspect and slope position along a fire chronosequence. Circular nested plots (CNP’s) were randomly located within these strata to measure effects on plant community. Results/Conclusions Field observations and preliminary analysis indicate that cheatgrass is more likely to persist on south facing aspects at low to mid elevatio...
Background/Question/Methods Bromus tectorum (cheatgrass) is one of the most widespread invasive s... more Background/Question/Methods Bromus tectorum (cheatgrass) is one of the most widespread invasive species in the western United States. In sagebrush steppe rangeland it alters fire frequency, soil moisture, and nutrient dynamics, decreasing the value of rangeland for wildlife and livestock and increasing costs associated with fire remediation and habitat restoration. Land managers have observed cheatgrass expansion into areas that were previously uninvaded in the Southern Rocky Mountain region. Currently cheatgrass invasion has been shown to exhibit positive feedbacks on plant community change, however, it is possible that management intervention soon after disturbance may restore negative feedbacks and promote recovery to a pre-disturbance community. We ask whether herbicide application can be used to avoid the process changes that cheatgrass can cause and promote desirable plant communities resistant to reinvasion. We collected baseline data on plant functional group cover in 8 burn...
Many ecological processes affect the amount of rainfall that infiltrates the soil profile and bec... more Many ecological processes affect the amount of rainfall that infiltrates the soil profile and becomes available for plant production. These processes include those that affect macroporosity and the soil surface condition, which influence the movement of water across the landscape and time available for infiltration. Simulation modelling provides a valuable means of exploring the effect of these processes on the retention or loss of resources from a system. This paper describes the eco-hydrological processes implemented in the SAVANNA.AU model in order to represent soil hydrology using a simple ecological approach and utilizing variables that are easily measured by managers and field ecologists.
The ideal free distribution is a biological model that explains the abundance of predators relati... more The ideal free distribution is a biological model that explains the abundance of predators relative to their prey. This analysis reapplies this theory to examine the distribution of domestic livestock relative to the availability of water and forage along a 150km. transect in the Karakum Desert of Turkmenistan. In this arid environment, the location, quality and quantity of stock water
... number, and length of stem segments sampled from the tallest stems within the tallest plant s... more ... number, and length of stem segments sampled from the tallest stems within the tallest plant strata for 3 willow species (Salix monticola Bebb, Salix geyeriana ... Reviews by Brian Cade, Evan Wolf,Linda Zeigenfuss, and 3 anonymous referees greatly improved the manuscript. ...
The seasonal assimilation and within-plant partitioning of 14CO2-carbon and 35SO2-sulfur in field... more The seasonal assimilation and within-plant partitioning of 14CO2-carbon and 35SO2-sulfur in field plots of mixed-grass prairie was investigated, as was the dry deposition of 35SO2 onto surfaces of dead leaves, litter, and soil, and possible effects of continuous low-level SO2 fumigation on these processes. The proportion of total net-assimilated carbon found below-ground was 45% in May, 51% in July, and
Three C4 graminoids, Kyllinga nervosa, Themeda triandra, and Hyparrhenia filipendula, were grown ... more Three C4 graminoids, Kyllinga nervosa, Themeda triandra, and Hyparrhenia filipendula, were grown in unbalanced factorial treatment designs of clipping height, clipping frequency, watering frequency, and ni-trogen availability for periods equivalent to one growing season, after ...
... Three uncommon plant species (aspen, willow, and Wyoming big sagebrush Artemisia tridentata .... more ... Three uncommon plant species (aspen, willow, and Wyoming big sagebrush Artemisia tridentata ... assessment ungulates management native natural regulations. Francis J Singer, David M Swift ... Richard S Inouye, Nancy Huntly, G Wayne Minshall, JE Anderson in Biogeochemistry ...
Background/Question/Methods Cheatgrass (Bromus tectorum) is one of the most prolific invaders of ... more Background/Question/Methods Cheatgrass (Bromus tectorum) is one of the most prolific invaders of western rangelands, increasing fire frequency, decreasing wildlife and livestock habitat value and limiting the use of prescribed fire as a management tool. Once cheatgrass becomes established, it modifies the environment to create an ecologically stable state that is resilient to both successional processes and management intervention. The objective of the study reported here is to evaluate landscape scale constraints on conversion of perennial grass/shrublands to cheatgrass dominated stable states. Study sites were located in southeastern Wyoming and stratified by aspect and slope position along a fire chronosequence. Circular nested plots (CNP’s) were randomly located within these strata to measure effects on plant community. Results/Conclusions Field observations and preliminary analysis indicate that cheatgrass is more likely to persist on south facing aspects at low to mid elevatio...
Background/Question/Methods Bromus tectorum (cheatgrass) is one of the most widespread invasive s... more Background/Question/Methods Bromus tectorum (cheatgrass) is one of the most widespread invasive species in the western United States. In sagebrush steppe rangeland it alters fire frequency, soil moisture, and nutrient dynamics, decreasing the value of rangeland for wildlife and livestock and increasing costs associated with fire remediation and habitat restoration. Land managers have observed cheatgrass expansion into areas that were previously uninvaded in the Southern Rocky Mountain region. Currently cheatgrass invasion has been shown to exhibit positive feedbacks on plant community change, however, it is possible that management intervention soon after disturbance may restore negative feedbacks and promote recovery to a pre-disturbance community. We ask whether herbicide application can be used to avoid the process changes that cheatgrass can cause and promote desirable plant communities resistant to reinvasion. We collected baseline data on plant functional group cover in 8 burn...
Many ecological processes affect the amount of rainfall that infiltrates the soil profile and bec... more Many ecological processes affect the amount of rainfall that infiltrates the soil profile and becomes available for plant production. These processes include those that affect macroporosity and the soil surface condition, which influence the movement of water across the landscape and time available for infiltration. Simulation modelling provides a valuable means of exploring the effect of these processes on the retention or loss of resources from a system. This paper describes the eco-hydrological processes implemented in the SAVANNA.AU model in order to represent soil hydrology using a simple ecological approach and utilizing variables that are easily measured by managers and field ecologists.
The ideal free distribution is a biological model that explains the abundance of predators relati... more The ideal free distribution is a biological model that explains the abundance of predators relative to their prey. This analysis reapplies this theory to examine the distribution of domestic livestock relative to the availability of water and forage along a 150km. transect in the Karakum Desert of Turkmenistan. In this arid environment, the location, quality and quantity of stock water
... number, and length of stem segments sampled from the tallest stems within the tallest plant s... more ... number, and length of stem segments sampled from the tallest stems within the tallest plant strata for 3 willow species (Salix monticola Bebb, Salix geyeriana ... Reviews by Brian Cade, Evan Wolf,Linda Zeigenfuss, and 3 anonymous referees greatly improved the manuscript. ...
The seasonal assimilation and within-plant partitioning of 14CO2-carbon and 35SO2-sulfur in field... more The seasonal assimilation and within-plant partitioning of 14CO2-carbon and 35SO2-sulfur in field plots of mixed-grass prairie was investigated, as was the dry deposition of 35SO2 onto surfaces of dead leaves, litter, and soil, and possible effects of continuous low-level SO2 fumigation on these processes. The proportion of total net-assimilated carbon found below-ground was 45% in May, 51% in July, and
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Papers by Michael Coughenour