Anthropogenic disturbances alter responses of understory plants to deer density: A 9-year deer density control experiment
Anthropogenic disturbances alter responses of understory plants to deer density: A 9-year deer density control experiment
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DOI：
10.1016/j.foreco.2023.120928
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发表时间：
2023-03-27
影响因子：
3.7
通讯作者：
Hiura，Tsutom
中科院分区：
文献类型：
--
作者：
Takafumi，Hino;Agetsuma，Naoki;Hiura，Tsutom
鹿群数量的增加及其分布的扩大改变了北半球植物群落的多样性和生物量。此外，氮沉降和伐木等人为干扰威胁着森林许多部分的植物多样性。因此，研究鹿群对氮沉降和采伐条件下植物群落的影响，对了解和保护森林生态系统植物多样性具有重要意义。在日本北部寒温带次生林进行了为期9年的鹿密度控制试验，控制了3个水平（圈闭：0只鹿/km2、低：10只鹿/km2、高：20只鹿/km2）和4种人为干扰（无人为干扰[控制]、氮添加、伐木和氮添加与伐木相结合）。研究了鹿群密度和人为干扰处理对林下维管植物（草本、蕨类、乔木、禾本科、难食性、藤本和灌木）和所有林下维管植物物种丰富度和植被覆盖的影响。将鹿密度、人为干扰及其相互作用对物种丰富度、植被覆盖度和辛普森指数的恒定效应（不考虑经过年）和临时效应（考虑经过年）作为完整模型的单独参数进行估计，并选择最佳模型。高鹿群密度对部分生命形式和所有物种的物种丰富度产生负面影响，并随着时间的推移加速了这些影响。高鹿群密度对大多数生命形式的植被覆盖度都有负面影响，且随着时间的推移，这种影响逐渐减弱。封育对部分生命形式的物种丰富度有负面影响，对大部分生命形式和所有物种的植被覆盖度有积极影响。随着时间的推移，对覆盖物的影响越来越大。施氮加速了高鹿密度对灌木物种丰富度的负面影响。另一方面，伐木减少了高鹿密度对所有物种丰富度的负面影响。上年度调查中，有采伐的鹿高密度样地的适口物种盖度约为未受人为干扰的鹿高密度样地的9倍。高鹿群密度和采伐降低了辛普森多样性指数得分。这些结果表明，鹿密度、人为干扰及其相互作用的影响随时间而变化。必须考虑到这些相互作用，以管理鹿对森林生态系统的影响。
The increasing deer population and their expanding distribution have altered the diversity and biomass of the plant community in the northern hemisphere. Furthermore, anthropogenic disturbances such as nitrogen deposition and logging threaten plant diversity in many parts of the forests. Therefore, it is necessary to investigate the effects of deer on plant communities under nitrogen deposition and logging conditions to understand and conserve plant diversity in forest ecosystems. We conducted a field experiment that controlled three levels of deer densities (exclosure: 0 deer/km2, low: 10 deer/km2, and high: 20 deer/km2) and four anthropogenic disturbances (without anthropogenic disturbances [control], nitrogen addition, logging, and nitrogen addition and logging combined) in a cool temperate secondary forest in northern Japan for nine years. We surveyed the effects of deer density and anthropogenic disturbance treatments on species richness and vegetation cover of life forms (forbs, ferns, trees, graminoids, unpalatable species, vines, and shrubs) and all species of understory vascular plants. We estimated the constant effect (without the elapsed year) and the temporary effect (with the elapsed year) of deer density, anthropogenic disturbances, and their interactions on the species richness, vegetation cover, and Simpson’s index as separate parameters in full models and selected the best model. The high deer density negatively affected the species richness of some life forms and all species and accelerated these effects over time for all species. The vegetation covers of most of the life forms were negatively affected by high deer density, and the effect was reduced over time. In contrast, the exclosure negatively affected the species richness of some life forms and positively affected the vegetation cover of most of the life forms and all species. The effect on the cover accelerated over time. Nitrogen addition accelerated the negative effect of high deer density on the species richness of shrubs. On the other hand, logging reduced the negative effect of high deer density on the species richness of all species. The cover of unpalatable species in the high deer density site with logging was approximately nine times higher than that in the high deer density site without anthropogenic disturbances in the last surveyed year. The high deer density and logging decreased the Simpson’s diversity index score. These results indicate that the effects of deer density, anthropogenic disturbances, and their interactions vary with time. These interactions must be considered to manage deer’s effect on forest ecosystems.