Relationships of pest grasshopper populations in Alberta, Canada to soil moisture and climate variables

This study examines regional relationships between climate, soil moisture, and pest grasshopper populations in Alberta. The objectives of this study are two-fold: (a) to investigate soil moisture as a potential predictor of pest grasshopper populations; and (b) to determine whether or not relationships between pest grasshopper populations and weather and soil moisture exist at the regional scale. Simple correlations and a modified chi-squared procedure are employed to investigate these relationships. Fall and spring soil moisture conditions appear to have some predictive capacity, showing strong associations to grasshopper abundance. Furthermore, regional relationships between temperature and soil moisture and the pest grasshopper populations are also identified. These relationships appear far stronger relative to low grasshopper populations, suggesting that population declines are easier to predict than outbreaks. Cool, wet weather in the spring and warm, dry weather in the fall and early winter are strongly associated with low populations. (c) 2007 Elsevier B.V. All rights reserved.