概括
在北极森林中的雪鞋种群表现出10年周期. 操纵食物和捕食者揭示了它们的综合作用,而不是添加的营养素,驱动了这些人口动态.
科学领域:
- 生态生态学 生态生态学
- 野生动物群体的动态.
- 玻里亚森林生态系统 玻里亚森林生态系统
背景情况:
- 北美北方森林中的雪鞋种群自然会经历周期性波动.
- 了解这些循环的驱动因素对于北极生态系统管理至关重要.
- 以前的研究表明,复杂的相互作用影响着子种群动态.
研究的目的:
- 调查补充食物和哺乳动物掠食者丰富对雪鞋子种群的影响.
- 确定营养添加对影响子密度和植物生长的作用.
- 为了阐明产生10年雪鞋子周期的机制.
主要方法:
- 一个因数实验在8年内在尤肯州的1平方公里的地块上进行.
- 操纵包括补充食品添加和捕食者排除.
- 通过施肥两个森林块来测试营养效应.
主要成果:
- 捕食者排斥使子密度增加了一倍,而在周期性高峰和下降期间,食物添加增加了三倍.
- 结合掠食者排斥和食物添加,子密度增加了11倍.
- 添加营养物质增强了植物生长,但没有显著影响子的密度.
结论:
- 子种群周期主要是由食物供应和掠食压力之间的相互作用驱动的.
- 食物和掠食者的协同效应表明,三种营养水平的相互作用是关键.
- 与掠食和食物相比,营养素的可用性似乎在调节雪鞋子周期方面是一个不那么重要的因素.
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