The Role of Life History Processes in Primary Succession on an Alaskan Floodplain
The Role of Life History Processes in Primary Succession on an Alaskan Floodplain
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DOI：
10.2307/1938680
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发表时间：
1986-10
期刊：
影响因子：
4.8
通讯作者：
L. Walker;J. Zasada;F. Chapin
中科院分区：
文献类型：
--
作者：
L. Walker;J. Zasada;F. Chapin
在阿拉斯加内陆的塔纳纳河洪泛区的初级演替模式主要是由于随机事件和生活史特征之间的相互作用的DOM？昆虫种类杨柳（Salix alaxensis）、桤木（Alnus tenuifolia）、白杨（Populus balsam- iferd）和云杉（Picea glauca）的种子雨在不同年份间变化很大，但在以该物种为主的演替阶段最高。每个物种的一些种子到达各个阶段，所有物种的幼苗最初都存在于早期的演替现场。大量的，风分散的种子和快速的幼苗生长速度的杨柳和白杨导致他们丰富的建立在早期成功？单向植被-粉砂坝较重的桤木和云杉种子分布不广泛，但快速增长的桤木导致在20年内的淤泥条形成密集的桤木灌丛。我们没有发现四个研究物种的埋藏种子的证据。播种种子的杨柳，桤木，白杨只建立在早期演替植被淤泥和杨柳网站。云杉建立在这些相同的网站和桤木网站。云杉是唯一的物种，自然殖民中期和后期演替网站。清除枯枝落叶和森林地面使所有物种在所有地点发芽。洪水导致大量死亡的幼苗在早期的继承网站。结合寿命短，草食动物的野兔，和阴影不耐受消除杨柳从中期连续桤木为主的网站。此后，寿命的差异解释了从桤木到白杨再到云杉的演替变化。促进物种之间的相互作用并没有出现必要的解释物种组成的变化，在这一主要的演替序列。
The pattern of primary succession on the floodplain of the Tanana River in interior Alaska resulted largely from interactions between stochastic events and life history traits of the dom? inant species. Seed rain by willow {Salix alaxensis), alder {Alnus tenuifolia), poplar {Populus balsam- iferd), and spruce {Picea glauca) varied substantially among years but was highest in the successional stage dominated by that species. Some seeds of each species arrived in all stages, and seedlings of all species were initially present in early successional sites. The copious, wind-dispersed seeds and rapid seedling growth rates of willow and poplar resulted in their abundant establishment on early succes? sional vegetated-silt bars. Heavier alder and spruce seeds were less widely distributed, yet rapid growth rates of alder resulted in dense alder thickets within 20 yr of silt bar formation. We found no evidence of buried seed of the four study species. Sown seeds of willow, alder, and poplar established only in early successional vegetated-silt and willow sites. Spruce established in these same sites and in alder sites. Spruce was the only species that naturally colonized mid and late successional sites. Removal ofthe litter and forest floor enabled all species to germinate in all sites. Flooding resulted in substantial mortality of seedlings in early successional sites. A combination of short life span, herbivory by hares, and shade intolerance eliminated willow from mid-successional alder-dominated sites. Thereafter differences in longevity explained successional change from alder to poplar to spruce. Facilitative interactions among species did not appear essential to explain changes in species composition in this primary successional sequence.