Demographic response of plant populations to habitat fragmentation and temporal environmental variability
Demographic response of plant populations to habitat fragmentation and temporal environmental variability
复制标题
植物种群对栖息地破碎化和时间环境变化的人口统计响应
DOI：
10.1007/s00442-009-1505-8
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发表时间：
2010
期刊：
影响因子：
2.7
通讯作者：
M. Ohara
中科院分区：
文献类型：
--
作者：
H. Tomimatsu;M. Ohara
许多植物物种目前存在于不同大小的零散种群中，同时它们也经历了不可预测的气候波动。然而，我们仍然对植物种群对这种时空环境变化的响应知之甚少。我们研究了日本北海道托卡奇平原林下多年生草本植物延龄草的种群动态，那里的森林破碎化对幼苗更新有显著影响。对一系列碎片大小的四个种群进行了6年的研究，并使用矩阵种群模型对数据进行了分析。不同种群的人均繁殖力(每株新兵数量)差异很大，但种群增长率(λ)的变化主要是由停滞和生长速率的变化驱动的，这表明碎片化种群繁殖力降低的总体趋势可能不容易转化为后续的动态。年际间λ的时间变异比种群间的空间变异大2倍以上，这一结果可能归因于不同人口比率之间相关结构的对比反应。λ的种群间变异被矩阵元素之间的负协变所抑制，这可能是由于密度依赖的调节以及某些元素不独立的固有约束，而矩阵元素之间的正协变导致了λ的大的时间变化。我们的结果表明，种群动态对生境破碎化和环境的时间变异性做出了不同的反应，强调了在人口模型中区分这些空间和时间变化的必要性。虽然在随机模拟中没有预测种群数量会下降，但当前栖息地大小和植物密度之间的相关性表明，历史λ与栖息地大小正相关。
Many plant species currently exist in fragmented populations of different sizes, while they also experience unpredictable climatic fluctuation over time. However, we still understand little about how plant demography responds to such spatial and temporal environmental variability. We studied population dynamics of an understory perennial herbTrillium camschatcensein the Tokachi plain of Hokkaido, Japan, where a significant effect of forest fragmentation on seedling recruitment was previously reported. Four populations across a range of fragment sizes were studied for 6 years, and the data were analyzed using matrix population models. Per capita fecundity (the number of recruits per plant) varied greatly among populations, but the variation in population growth rates (λ) was mainly driven by the variation in stasis and growth rates, suggesting that the general trend of reduced fecundity in fragmented populations may not be readily translated into subsequent dynamics. Temporal variation in λ among years was more than 2 times larger than spatial variation among populations, and this result was likely attributable to the contrasting response of correlation structures among demographic rates. The among-population variation in λ was dampened by negative covariation between matrix elements possibly due to density-dependent regulation as well as an inherent constraint that some elements are not independent, whereas positive covariation between matrix elements resulted in large temporal variation in λ. Our results show that population dynamics responded differently to habitat fragmentation and temporal variability of the environment, emphasizing the need to discriminate these spatial and temporal variations in demographic models. Although no populations were projected to be declining in stochastic simulations, correlation between current habitat size and plant density implies historical λ is positively related to habitat size.
DOI：
--
发表时间：
2004
期刊：
Biological Conservation 117
影响因子：
--
作者：
Tomimatsu;H.;Ohara;M.
通讯作者：
M.