Estimation of dieback process caused by herbivory in an endangered root-sprouting shrub species, Paliurus ramosissimus (Lour.) Poir., using a shoot-dynamics matrix model
Estimation of dieback process caused by herbivory in an endangered root-sprouting shrub species, Paliurus ramosissimus (Lour.) Poir., using a shoot-dynamics matrix model
复制标题
使用芽动力学矩阵模型估计濒临灭绝的根发芽灌木 Paliurus ramosissimus (Lour.) Poir. 中食草引起的枯死过程
DOI：
10.1007/s10144-013-0414-1
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发表时间：
2014
影响因子：
1.7
通讯作者：
Yamamoto K and Takada T
中科院分区：
文献类型：
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作者：
Ishihama F;Fujii S;Yamamoto K and Takada T
死亡率是种群动态的一个关键参数，由于死亡频率极低，因此很难测量长寿树木或无性系草本物种的死亡率。基于芽补充的模型将有助于在没有足够数量的观察到的死亡的情况下估计物种的种群命运。现有的矩阵模型适用于生理独立芽的动力学，但不适用于生理依赖性芽的动力学。我们为具有生理依赖性芽的植物开发了芽动态模型，并使用该模型来估计食草和保护措施对长寿芽发灌木物种青蒿（鼠李科）动态的影响。这种濒危灌木的两个种群因梅花鹿的食草行为而受到严重破坏。损害主要是新发芽。在为期 8 年的调查中，没有观察到单株植物死亡，我们无法估计死亡率。因此，根据个体的出生和死亡来预测人口动态是不可能的。因为P。由于分枝是一种枝条萌芽物种，我们使用枝条动力学模型来估计个体的衰退。使用此模型，我们估计两个种群中每个个体的芽数减少 80% 的时间分别为 37.8 和 37.2 年。这些长度表明迫切需要采取保护措施来防止食草动物，尽管在实地调查中没有观察到任何个体死亡。如果通过保护措施完全防止新芽的食草，预计食草损害的恢复时间分别为 28.7 和 29.2 年。
Mortality, a critical parameter for population dynamics, is difficult to measure in long-lived trees or clonal herbaceous species because of the extremely low frequency of deaths. A model based on shoot recruitment would be helpful to estimate the population fate of species without a sufficient number of observed deaths. Existing matrix models are applicable to the dynamics of physiologically independent shoots, but not to physiologically dependent ones. We developed a shoot-dynamics model for plants with physiologically-dependent shoots, and used the model to estimate the effects of herbivory and conservation measures on the dynamics of a long-lived, shoot-sprouting shrub species,Paliurus ramosissimus(Rhamnaceae). Two populations of the endangered shrub have been severely damaged by herbivory by sika deer. The damage was mainly to new sprouting shoots. No deaths of individual plants were observed during an 8-year survey, and we could not estimate mortality. Thus, prediction of population dynamics based on births and deaths of individuals was impossible. BecauseP. ramosissimusis a shoot-sprouting species, we instead estimated the decline of individuals using a shoot-dynamics model. Using this model, we estimated the time to an 80 % decrease in shoot number per individual in the two populations at 37.8 and 37.2 years. These lengths suggest an immediate need for conservation measures to prevent herbivory even though no death of any individual was observed in the field survey. The estimated recovery times from the herbivory damage were 28.7 and 29.2 years if herbivory of new shoots is completely prevented by conservation measure.