THE POPULATION ECOLOGY OF A DUNE THISTLE, CIRSIUM RHOTHOPHILUM (ASTERACEAE)
THE POPULATION ECOLOGY OF A DUNE THISTLE, CIRSIUM RHOTHOPHILUM (ASTERACEAE)
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沙丘蓟 Cirsiium Rhothophilum（菊科）的种群生态学
DOI：
10.1002/j.1537-2197.1983.tb10855.x
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发表时间：
1983
影响因子：
3
通讯作者：
C. Gautier
中科院分区：
文献类型：
--
作者：
P. Zedler;Kathleen Guehlstorff;Carla Scheidlinger;C. Gautier
1978年至1979年，在加利福尼亚州圣巴巴拉县北部的沿海沙丘上对蓟进行了种群研究。在永久标记的样带上观察幼苗的建立、生长、开花和结果。共有1041只个体被记录在案。尽管在研究期间死亡率为41%，但平均人口特征变化非常小。研究发现，嗜红蓟是单果的，但寿命相对较长。从莲座丛的大小、生长和不同大小类别中产生开花个体的莲座丛的比例推断，平均每株植物的营养生长期可能超过5年。嗜红假单胞菌的生长分析因茎的表面下分枝而变得复杂，据推测是虫害和沙埋的结果。对果穗的解剖表明，健全瘦果仅占潜在瘦果总数的22%左右。约20%的不健全瘦果上有明显的虫害。考虑到头部瘦果和整个头部未成熟的瘦果的损失，昆虫估计至少会破坏25%的瘦果。瘦果很容易萌发，似乎只有轻微的休眠。埋藏实验表明，随着埋藏深度的增加，出苗率急剧下降，在8 cm处为零。尽管沙丘栖息地的性质是动态的，但嗜红假单胞菌的种群似乎是稳定的。相对较大的体型和快速生长并适应埋葬的能力使嗜红假单胞菌能够平均承受环境的变迁。
A population study of a thistle, Cirsium rhothophilum, was carried out in the coastal dunes of northern Santa Barbara County, California during 1978 and 1979. Seedling establishment, growth, flowering, and fruiting were observed in permanently marked transects. A total of 1,041 individuals were recorded. Despite 41% mortality during the year of study, the average population features changed remarkably little. Cirsium rhothophilum was found to be monocarpic but relatively long-lived. Extrapolations from rosette size growth and proportions of rosettes in different size classes giving rise to flowering individuals suggest that the average plant may have a vegetative stage of more than 5 years. Growth analysis of C. rhothophilum is complicated by the subsurlace branching of stems, presumed to be the result of insect damage and sand burial. Dissection of fruiting heads showed that sound achenes were only about 22% of the total number of potential achenes. Insect damage was evident on about 20% of the unsound achenes. Considering both the loss of achenes within heads and of entire heads which failed to mature, insects are estimated to destroy at least 25% of the achenes. Achenes germinate readily and do not appear to have more than mild dormancy. A burial experiment showed that emergence declined sharply with depth of burial to zero at 8 cm. Despite the dynamic nature of the dune habitat, C. rhothophilum populations appear stable. The relatively large size and ability to grow rapidly and adapt to burial allow C. rhothophilum to average out environmental vicissitudes.