Transients drive the demographic dynamics of plant populations in variable environments.
Transients drive the demographic dynamics of plant populations in variable environments.
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DOI：
10.1111/1365-2745.12528
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发表时间：
2016-03
期刊：
影响因子：
--
通讯作者：
Hodgson DJ
中科院分区：
文献类型：
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作者：
McDonald JL;Stott I;Townley S;Hodgson DJ
结构植物种群在可变环境中的动态可分解为由生命率贡献的“渐近”生长和由偏离稳定阶段结构引起的“瞬时”生长。我们将这个框架应用于植物种群投影矩阵模型纵向研究的大型全球数据库。我们问，在随机环境中，瞬时繁荣和萧条对植物种群动态轨迹的相对贡献是什么？这一贡献是根据系统发育、生长形式还是每个种群和每个物种的生命阶段数来划分的？我们发现，瞬变对结果轨迹的贡献接近50%或更多，这取决于瞬变和稳定的贡献是根据它们对种群动态的绝对贡献还是净贡献来划分的。瞬时贡献率和渐近贡献率都受到所建模型生命阶段数量的严重影响。我们讨论了瞬变的驱动因素是否应该被认为是真实的生态现象，还是研究设计和建模策略的人工制品。我们没有发现在瞬变对随机增长的贡献中存在系统发育信号的证据，也没有明确的模式与增长形式相关。我们发现了一个令人惊讶的趋势，即植物种群随着生命速率的时间变化而繁荣而不是衰退，并且随机增长率随着繁荣趋势的增加而增加。综合。瞬时动态对随机种群动态有很大贡献，但在使用随机分析的生态和进化研究中往往被忽视。更好地理解对种群结构波动的瞬时反应将产生更好的植物种群管理策略，并更好地掌握现实世界中的进化动态。
The dynamics of structured plant populations in variable environments can be decomposed into the ‘asymptotic’ growth contributed by vital rates, and ‘transient’ growth caused by deviation from stable stage structure. We apply this framework to a large, global data base of longitudinal studies of projection matrix models for plant populations. We ask, what is the relative contribution of transient boom and bust to the dynamic trajectories of plant populations in stochastic environments? Is this contribution patterned by phylogeny, growth form or the number of life stages per population and per species? We show that transients contribute nearly 50% or more to the resulting trajectories, depending on whether transient and stable contributions are partitioned according to their absolute or net contribution to population dynamics. Both transient contributions and asymptotic contributions are influenced heavily by the number of life stages modelled. We discuss whether the drivers of transients should be considered real ecological phenomena, or artefacts of study design and modelling strategy. We find no evidence for phylogenetic signal in the contribution of transients to stochastic growth, nor clear patterns related to growth form. We find a surprising tendency for plant populations to boom rather than bust in response to temporal changes in vital rates and that stochastic growth rates increase with increasing tendency to boom. Synthesis. Transient dynamics contribute significantly to stochastic population dynamics but are often overlooked in ecological and evolutionary studies that employ stochastic analyses. Better understanding of transient responses to fluctuating population structure will yield better management strategies for plant populations, and better grasp of evolutionary dynamics in the real world.