Plant extinction dynamics in an insular metacommunity
Plant extinction dynamics in an insular metacommunity
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DOI：
10.1111/j.1600-0706.2008.16816.x
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发表时间：
2009-02-01
期刊：
影响因子：
3.4
通讯作者：
Neufeld, Christopher J.
中科院分区：
文献类型：
--
作者：
Burns, Kevin C.;Neufeld, Christopher J.
随着时间的推移，当地社区的组成发生变化（即物种更替）是岛屿生物学中的一种常见现象。然而，促进岛屿之间和物种之间物种更替变化的机制知之甚少。为了更好地了解物种周转率变化的原因，我们评估了加拿大西海岸18个小岛上植物种群的定殖和灭绝动态。在1997年，我们量化了10种木本被子植物的总人口规模。十年后，我们重新采样岛屿，以测试是否：1）物种周转发生，2）殖民化事件被灭绝事件所抵消，2）岛屿之间灭绝率的变化与人口规模，平均植物高度，岛屿面积，岛屿隔离或每个岛屿的暴露于海洋出生的干扰，和3）物种之间灭绝率的变化与植物生活史特征。结果表明，绝灭事件的数量远多于定殖事件，表明该地区的生态系统处于“不平衡”状态。岛屿之间的灭绝率的变化是无关的岛屿面积和隔离。然而，灭绝率增加暴露于海洋出生的干扰和减少与初始人口规模和平均植物高度。具有较厚、较坚韧叶片的物种（即单位面积的叶片质量较高）比具有较薄、较纸质叶片的物种更不容易灭绝。总体结果表明，物种更替很常见，主要是由灭绝引起的。灭绝率的变化似乎是由于岛屿效应（曝光，人口规模和植物的身高）和物种效应（叶韧性）之间的相互作用，这表明海洋出生的干扰起着关键作用，在确定metacompatiity结构。
Changes in the composition of local communities through time (i.e. species turnover) is a common phenomenon in insular biology. However, the mechanisms promoting variation in species turnover, both among islands and among species, are poorly understood. In an effort to better understand the causes of variation in species turnover, we evaluated the colonization and extinction dynamics of plant populations on 18 small islands off the west coast of Canada. In 1997, we quantified total population sizes of 10 woody angiosperm species. A decade later, we resampled islands to test whether: 1) species turnover occurred, 2) colonization events were offset by extinction events, 2) variation in extinction rates among islands was associated with population sizes, average plant heights, island area, island isolation or each island's exposure to ocean-born disturbances, and 3) variation in extinction rates among species was associated with plant life history traits. Results showed that extinction events outnumbered colonization events, suggesting that the metacommunity is in 'disequilibrium'. Variation in extinction rates among islands was unrelated to island area and isolation. However, extinction rates increased with exposure to ocean-born disturbances and decreased with both initial population sizes and average plant heights. Species with thicker, tougher leaves (i.e. high leaf mass per area) were less prone to extinction than species with thinner, more papery leaves. Overall results indicate that species turnover is common and that it is generated primarily by extinction. Variation in extinction rates appears to result from an interaction between among-island effects (exposure, population size and plant stature) and among-species effects (leaf toughness), suggesting that ocean-born disturbances play a key role in determining metacommunity structure.