外来植物薇甘菊对本地植物凋落物分解的影响

 外来植物薇甘菊（Mikania micrantha HBK.）已入侵华南许多地区，并造成严重危害。探讨了外来植物薇甘菊凋落物对4种本地植物大叶榕（Ficus virens）、潺槁树（Litsea glutinosa）、樟树（Cinnamomum camphora）和台湾相思（Acacia confusa）凋落物分解的影响。凋落物分解采用网袋法，将薇甘菊凋落物分别与本地植物凋落物按3个比例混合，3个比例为，m（薇甘菊）∶m（本地植物） = M₁（1∶4），M₂（1∶1）和M₃（4∶1）。分解60 d后，测定凋落物的分解速率与养分释放。结果表明，薇甘菊与本地植物凋落物混合比例为M₁时，凋落物分解速率变慢，但在M₃时，凋落物的分解速率变快。与单独本地凋落物养分释放相比，薇甘菊凋落物混入后C释放有所下降，而N素释放量有所提高，这种N释放量的增加可能会对薇甘菊的入侵产生正反馈作用。

Effects of Exotic Plant Mikania micrantha H.B.K. on Litter Decomposition of Several Native Plants

The exotic plant Mikania micrantha H.B.K. has invaded many forests in south China and caused a great damage. The effect of Mikania micrantha invasion on litter decomposition of native plants was studied. The litterbag technique was used to quantify the litter decomposition rate. Litter of the invasive plant Mikania micrantha was mixed with the litter of 4 native plants (Ficus virens, Litsea glutinosa, Cinnamomum camphora, Acacia confuse) respectively as 3 ratios: M₁(1∶4), M₂(1∶1) and M₃(4∶1). After 60—days decay, the litter decomposition rate and nutrient (C, N) release were determined. The results showed that under M₁, the mixed litter decomposition rate decreased, while, under M₃, the mixed litter decomposition rate increased. In addition, C released from the mixed litter decreased, while N release increased, and N released the most under M₃.The increased N release might represent positive feedback to Mikania micrantha invasion.