Sericea lespedeza (Lespedeza cuneata) is a highly invasive plant in Kansas and threatens native prairies. Historically Kansas had harsh, cold winters. However in recent years, Kansas has had mild winter temperatures and reduced snowfall. Very few studies have been performed to examine what the effects of these mild winters will have on invasive species. The purpose of our study was 1) to determine if exposure to cold temperatures is lethal to dormant sericea lespedeza plants 2) to determine if the length of time to cold temperature exposure has an effect on dormant sericea lespedeza plants and 3) to determine if removal of winter grass cover significantly altered soil temperatures. For objectives 1 and 2, we subjected wild, dormant sericea lespedeza plants to below freezing temperatures for 6 to 48 hours. After the cold treatment the plants were transferred to a greenhouse to monitor for regrowth. For objectives 3, we compared soil temperatures of unburned and fall burned prairies.
Results/Conclusions
We analyzed the data using a logistic regression model and focused on the AICc value to choose the best model. The time and temperature interaction model was chosen with 97% support. At six hours all four cold treatment temperatures gave the plants a cold shock but did not reduce the probability of regrowth. Plants subjected to -10°C for 48 hours had the lowest probability of regrowth. We used a repeated measures ANOVA to compare the two prairie soil temperatures and found there is a significant difference. Natural barriers, such as climate can be an effective, natural method to control invasive species. With one less natural barrier invasive species, such as sericea lespedeza, will likely continue to increase its range and to threaten native vegetation.