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

促进自然种群限制和调节的主导机制往往在同一物种的不同地点和同一种群的不同时期有所不同。来自美国西部草原的蚱蜢种群证明了这种可变性。根据对蚱蜢的独立长期实验研究，PI发现蒙大拿州的蚱蜢数量有限，而内布拉斯加州的蚱蜢数量有限。本研究的目的是综合这些研究关于不同生物相互作用和密度独立死亡率在不同年份不同地点的相对重要性的变化。综合表明，捕食者限制在低食物丰度下占主导地位，而食物限制在高食物丰度下占主导地位。PI将在蒙大拿州和内布拉斯加州进行一系列的实地实验来验证这些假设。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，蚱蜢尤其被认为是农业系统和牧场的害虫。本研究将为这一分布广泛的草食性物种的种群动态和控制机制提供有价值的信息。＊＊＊

9317984 Belovsky 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. ***