Extrapolating potential crop damage by insect pests based on land use data: examining inter-regional generality in agricultural landscapes

Abstract

ContextInter-regional relationships between landscape factors and biological responses under natural conditions are important but difficult to predict because of the differences in each landscape context and local environment. ObjectivesTo examine the inter-regional variability in relation to landscape factors and the biological response of an insect pest, we extrapolated a damage prediction model (‘the original model’) for rice using land-use data. We hypothesized that the original model would be applicable to new regions, but the predictive accuracy would be reduced. We predicted that adjusting the parameter coefficients would improve model performance (‘the adjusted model’). MethodsA field experiment was conducted in two regions that had a similar landscape context with the original region, in different years for each region, for four years in total. The proportion of rice damage and surrounding land-use within a 300-m radius was investigated. ResultsWhen ‘the original model’ was assigned to combined data from the original and extrapolated regions, the relationship between observed and predicted values was statistically significant, suggesting that there was an inter-regional common relationship. The relationship was not statistically significant if the model was applied only to the new regions. The adjusted model improved by 14% compared with the original model.ConclusionsThese results imply that in this pest–crop system, a common inter-regional biological response to arthropods is likely because of landscape factors, although local environmental factors must be considered. Application of such relationships is needed to identify or prevent pest hazards by offering region-wide management options.