Collaborative Research: Regulation of Rangeland Grasshopper Populations and Communities: Differing Dominant Mechanisms over Time and Space

9317938约恩促进自然种群的限制和调节的主导机制往往不同地点的同一物种，并随着时间的推移，同一人口。来自美国西部草原的蝗虫种群证明了这种变异性。根据对蚱蜢的独立长期实验研究，PI发现蒙大拿州的种群食物有限，而内布拉斯加州的种群捕食者有限。本研究的目的是综合这些研究方面的变化相对重要性的不同的生物相互作用和密度无关的死亡率在不同的地点在不同的年份。综合表明，捕食者的限制将占主导地位，在低食物丰富度，而食物限制将占主导地位，在高食物丰富度。PI将在蒙大拿州和内布拉斯加州进行一系列现场实验，以测试这些假设。 %从基础研究的角度来看，该项目将有助于确定不同生物和非生物因素对食草动物种群的相对作用。此外，蝗虫尤其是农业系统和牧场的害虫。这项研究将提供有价值的信息，人口动态和机制，以控制这一广泛的草食动物物种。 ***

9317938 Joern The dominant mechanism promoting the limitation and regulation of natural populations often varies among sites for the same species, and over time periods for the same population. Grasshopper populations from the western US grasslands demonstrate this variability. Based upon independent long-term experimental studies with grasshoppers, the PI's have found that in Montana populations are food limited, whereas in Nebraska populations are predator limited. The purpose of this research is to synthesize these studies with regard to the changing relative importance of different biotic interactions and density independent mortality at different sites in different years. The synthesis suggests that predator limitation will dominate at low food abundance, whereas food limitation will dominate at high food abundance. The PI's will conduct a series of field experiments at the Montana and Nebraska sites to test these hypotheses. %%% From the standpoint of basic research, this project will help to determine the relative roles of different biotic and abiotic factors on herbivore populations. In addition, grasshoppers, in particular, are known to be pests in agricultural systems and rangelands. This study will provide valuable information regarding population dynamics and mechanisms to control this widespread group of herbivore species. ***