Population dynamics of redbay ( Persea borbonia) after laurel wilt disease: an assessment based on forest inventory and analysis data.

Shearman, Timothy; Wang, G.; Bridges, William

Laurel wilt disease (LWD) is a lethal fungal infection of woody plants in the Lauraceae, including redbay ( Persea borbonia). We used forest inventory and analysis (FIA) data from 2003 to 2011 to estimate redbay populations and see if any decline could be observed since the introduction of LWD. Throughout its entire range, the population estimate of redbay was about 862.2 ± 89.8 million in 2003, increasing to 951.8 ± 87.1 million in 2011. However, population estimates from 2003 to 2011 displayed a significant negative curvature, suggesting that the population might start to decline. The population in Georgia significantly decreased from 241.1 ± 11.9 million stems in 2003 to 150.3 ± 7.9 million in 2011. Results at the range-wide scale should be taken with caution, since the FIA estimates are based on a 5-year moving average. However, we show that the FIA data can also be used on a smaller scale. Redbay densities decreased significantly in plots surveyed before and after the reported infection by an average of 89.6 live redbay stems/ha. Density in plots without reported LWD were not statistically different between survey years. We developed a logistic regression model to predict the probability of redbay mortality due to LWD. Number of years since LWD infection was the most significant variable, with every increase in 1 year resulting in a 153.7 % increase in odds of death. Diameter was also a significant predictor, with an increase of 1 cm DBH resulting in a 5.0 % increase in odds of death.

POPULATION dynamics; LAUREL; WILT diseases; FOREST surveys; FUELWOOD

Biological Invasions, 2015, Vol 17, Issue 5, p1371

1387-3547

Academic Journal

10.1007/s10530-014-0799-6