Ramet Demography of a Clonal Invader, Arundo donax (Poaceae), in Southern California
Ramet Demography of a Clonal Invader, Arundo donax (Poaceae), in Southern California
复制标题
南加州克隆入侵者芦竹（禾本科）的分株种群统计
作者：
J. Decruyenaere;J. S. Holt
Arundo donax L.是一种多年生根茎植物，无性繁殖，已经入侵了整个地中海气候带的河岸生境。这项研究评估了两个氮有效性不同的加利福尼亚州河岸社区的唐氏艾美耳藻的分株人口学特征。在每个地点沿100米的横断面建立样方，并在已建立的种群的前进前沿定向。在一年多的时间里，每月评估形态和物候，以计算人口统计学参数，并在实验结束时挖掘和绘制根茎。冬虫夏草在高氮部位有季节性的补充，但在高氮部位没有休眠，而在低氮部位冬季没有发生补充，最大补充比高氮部位推迟了一个月。冬虫夏草的传播推迟到春季，与高氮地点相比，低氮地点的总体传播速度较低，在高氮地点，较低的初始密度、较大的新梢产量、较高的线形和面积增加量表明该种群传播得更快。温度和降水对冬虫夏草的季节性和补充量有一定的影响。在低氮部位的空隙中发现了几个最近建立的未成熟的丛生植物，这可能是由于洪水介导的繁殖体的扩散。与从根状茎芽繁殖的成熟种群不同，这些丛生植物的更新发生在嫩芽中。杜氏刺参和其他外来物种的基于生态的管理策略应该考虑到这里所描述的差异，并根据物种发生的当地条件进行调整。
Arundo donax L. is a rhizomatous perennial, asexually reproducing species that has invaded riparian habitats throughout Mediterranean climate zones. This research evaluated ramet demography of A. donax in two California riparian communities that differed in nitrogen availability. Quadrats were established along 100 m transects at each site and oriented across the advancing fronts of established populations. Morphology and phenology were assessed monthly over 1 year for calculation of demographic parameters and rhizomes were excavated and mapped at the end of the experiment. A. donax exhibited seasonal patterns of recruitment but no dormancy at the high nitrogen site, while at the low nitrogen site no recruitment occurred in the winter and maximum recruitment was delayed by a month relative to the high nitrogen site. Spread of A. donax was delayed until spring and lower overall in the low nitrogen site compared to the high nitrogen site, where lower initial density, greater production of shoots, and higher linear and areal addition indicated that this population was spreading more rapidly. Temperature and precipitation influenced seasonality and amount of recruitment of A. donax in this study. Several recently established, immature clumps were found in gaps at the low nitrogen site, likely due to flood-mediated dispersal of propagules. Recruitment in these clumps occurred from shoot buds, in contrast to the mature populations that reproduced from rhizome buds. Ecologically based management strategies for A. donax and other exotic species should account for differences such as those described here and be tailored to local conditions where the species occurs.