Abstract
Effects of annual prescribed burning on Viola raddeana, an endangered wetland herb species were examined. We conducted burned site and not burned site in November 2006 in habitat of V. raddeana. Densities of seedlings and over-wintered individuals were recorded and sizes of over-wintered individual were measured. Soil water contents, temperatures of near ground surface and rPPFD were also compared between the two sites. Seedling densities in burned site were higher than not burned site both in 2007 and 2008. Seedling density significantly increased from 2007 to 2008 in burned site. Over-wintered individual densities in burned site were larger than not burned site both in 2007 and 2008. Therefore, annual prescribed burning was effective for seedlings of Viola raddeana. On the other hand, the sizes of over-wintered individual in burned site were lower than those in not burned site. Continuous burning may reduce growth rates of individuals.
