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

9317938约恩促进限制和调节自然种群的主要机制对于同一物种来说，往往在不同的地点有所不同，对于同一种群，在不同的时间段内往往不同。来自美国西部草原的蝗虫种群证明了这种变异性。基于对蝗虫的独立的长期实验研究，PI发现在蒙大拿州的种群是食物有限的，而在内布拉斯加州的种群是有限的捕食者。这项研究的目的是综合这些关于不同生物相互作用的相对重要性和不同地点不同年份的密度非依赖死亡率的变化的研究。综合表明，在食物丰度较低时，捕食者的限制将占主导地位，而在食物丰度较高的情况下，捕食限制将占主导地位。PI将在蒙大拿州和内布拉斯加州进行一系列实地实验，以检验这些假设。从基础研究的角度来看，这个项目将有助于确定不同的生物和非生物因素对食草动物种群的相对作用。此外，蝗虫尤其是已知的农业系统和牧场中的害虫。这项研究将提供关于种群动态和控制这一广泛存在的食草动物种群的机制的有价值的信息。***

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. ***