Zonation of vegetation along a burial gradient on the leeward slopes of Lake Huron sand dunes
Zonation of vegetation along a burial gradient on the leeward slopes of Lake Huron sand dunes
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DOI：
10.1139/b04-163
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发表时间：
2005-02-01
期刊：
影响因子：
--
通讯作者：
Maun, MA
中科院分区：
文献类型：
--
作者：
Dech, JP;Maun, MA
海岸沙丘植物群落从海滩到内陆边缘的分带性是世界公认的；然而，这种模式的原因仍然存在争议，因为几个环境因素的协方差，如砂埋、盐雾和小气候，沿着垂直于海岸线的梯度。为了最大限度地减少这种复杂的海岸-内陆梯度的混杂影响，并确定掩埋对植物群落组成的直接影响，我们研究了沿掩埋梯度延伸至休伦湖海岸线的林分，这是由一系列抛物线状沙丘之间的可变井喷活动产生的，这些沙丘包括从海岸向内陆的第二山脊。我们采用点位法和1 m × 1 m样地量化每个抛物状沙丘林分的上层和下层植物群落，并确定物种重要性，这里定义为上层的密度、频率和优势度之和，而下层的频率和优势度之和。物种重要性-沙丘林分矩阵的对应分析表明，植物群落组成在初级排序轴上与埋藏活动指数密切相关（上层和下层的r2分别为0.40和0.87）。埋藏与物种丰富度和多样性的变化、优势物种的转移以及基于埋藏耐受性的物种更替有关。这些数据支持了沙丘埋藏是地带性的主要因素的假设，这种地带性可以延伸到沙丘之外，包括木本物种群落。
The zonation of coastal dune plant communities from the beach to their inland margin is recognized worldwide; however, the cause of this pattern remains controversial because of the covariance of several environmental factors, such as sand burial, salt spray, and microclimate, along a gradient perpendicular to the shoreline. To minimize the confounding influence of this complex shore-inland gradient and determine the direct effects of burial on plant community composition, we examined stands along a burial gradient that extended parallel to the Lake Huron coastline, produced by variable blowout activity amongst a series of parabolic dunes comprising the second ridge inland from the coast. We used the point-quarter method and 1 m x 1 m plots to quantify overstorey and understorey plant communities in each parabolic dune stand and determined species importance, here defined as the sum of density, frequency, and dominance for the overstorey and the sum of frequency and dominance only for the understorey. Correspondence analyses of the species importance - dune stand matrices elucidated a pattern of plant community composition on the primary ordination axis that was strongly related to an index of burial activity (r2 = 0.40 and 0.87 for the overstorey and understorey, respectively). Burial was associated with changes in species richness and diversity, shifts in dominant species, and species replacement based on burial tolerance across the gradient. These data support the hypothesis that burial in sand dunes is a major causative factor of zonation, which can extend beyond the foredunes and include communities of woody species.