Modern management techniques to maintain rangelands and deter encroachment of juniper into grassland habitats currently includes fire prescription. Additionally, a large body of research has indicated that fire has multiple benefits to grasslands resulting in increased diversity of flora and fauna. In the semi-arid grassland of the Agua Fria National Monument, fire treatments may be able to provide similar advantages. This study considers two methods of fire prescription on the Agua Fria National Monument within central Arizona: 1) Juniper thinning with pile burning; 2) Broadcast burning.
The Agua Fria National Monument upland ecosystem has limited research focusing on semi-arid grassland and juniper stand’s response to implemented treatments over time. The four year monitoring duration of this study aids in assessing the outcome of treatments and reaching the objectives of the management plan.
Vegetation in 981 quadrats was measured for species richness, cover, densities, height, and biomass during the fire prescription period from 2009 through 2013. The study was divided into two treatment types: 1) Juniper cutting and pile burn; 2) Broadcast burn areas in open grasslands.
Results of this study provide consistent examples of vegetative change and community movement towards positive response. Percent composition of overall vegetation is 5 – 30% with >50% of litter, bare ground and rock cover. Juniper sites have immediate consequences from tree thinning activities that may be beneficial to wildlife, particularly as connective corridors pronghorn antelope. Grass height was significantly reduced as well as forb density. Forbs that are highly responsive to environmental factors indicate an increase after the second year. Analysis results from grasslands indicated that cactus and unpalatable shrubs are reduced by fire but a return to pre-burn conditions occur by the third year after fire disturbance. Percent cover of perennial grasses has shown a slow increase. Wright’s buckwheat, a palatable shrub, has increased in density and height, indicating fire adaptations in the species. Species richness was reduced in the first year but increase in density continues into the third year after burn.
Land use has changed drastically over the years as techniques modernize and new generations of people emerge. Each new generation chances and adapts the practices they need and the practices of their time. Have the newer practices hurt the land more so than practices used by previous generations? Or is the land changing naturally? In this paper, I will be focusing on a specific section of land in Arizona. The land is located in the Southernmost portion of Game Unit 19A. I have analyzed the techniques used by three distinct generations: Native Americans, original ranchers and miners, and modern ranchers and hunters. But looking at the differences between each generation, I have been able to pick out techniques that may have contributed to how the land is today. Those techniques include hunting, ranching, and mining. I have also analyzed the density of mesquites in the area in order get a better understanding of how the soil and vegetation has changed for the past few decades. I have found that the techniques used by the three groups are similar in nature, but the way they are conducted are very different because of the mindset that has changed between each time period. The density of mesquite is showing that the land has been affected due to ranching and drought. While ranching is conducted by humans and lines up with my analyst of the generations, drought is not something that could have been affected by humans and therefore an independent factor as to how the land has changed. Overall, I was not able to pinpoint a specific generation or land use techniques that has caused more change than another. I have concluded that more research should be done in order to figure out what techniques could be doing more harm than we had originally thought.