Nutrient presses and pulses differentially impact plants, herbivores, detritivores and their natural enemies.
Nutrient presses and pulses differentially impact plants, herbivores, detritivores and their natural enemies.
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DOI：
10.1371/journal.pone.0043929
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Denno RF
中科院分区：
文献类型：
--
作者：
Murphy SM;Wimp GM;Lewis D;Denno RF
人为的营养物质输入到本地生态系统造成的波动，通常限制植物生长的资源，这对相关的食物网有重要的影响。这种从农业和城市生境进入附近自然系统的输入在全球范围内不断增加，并且可能变化很大，从零星到连续。尽管全球范围内增加了对本地生态系统的营养投入，但对本地植物及其相关食物网的补贴持续时间变化的后果知之甚少。具体而言，虽然一些研究已经研究了营养素补贴对本地生态系统的影响（营养素脉冲），但多年来重复引入营养素（营养素压力）更好地反映了人为营养素富集的持久性。因此，我们对比了一年的营养脉冲与四年的营养压力对节肢动物消费者在两个盐沼的影响。盐沼是解决营养脉冲和压力对生态系统和群落动态的差异影响的理想系统，因为人类发展和其他人为活动导致营养物质经常引入这些自然系统。我们发现，植物生物量和%N以及节肢动物密度下降后，营养脉冲结束，但在整个营养压力保持升高。值得注意的是，较高的营养水平比较低的营养水平施肥反应更强烈，捕食者/猎物的比例增加每年的营养压力，表明食物网的人为营养富集的反应可能需要数年才能充分体现自己。在两个沼泽地的植被也表现出明显的权衡之间增加%N和生物量在响应施肥。我们的研究强调，需要长期的，空间多样性的研究养分富集，以了解人为养分补贴的持续时间的变化如何影响本地生态系统。
Anthropogenic nutrient inputs into native ecosystems cause fluctuations in resources that normally limit plant growth, which has important consequences for associated food webs. Such inputs from agricultural and urban habitats into nearby natural systems are increasing globally and can be highly variable, spanning the range from sporadic to continuous. Despite the global increase in anthropogenically-derived nutrient inputs into native ecosystems, the consequences of variation in subsidy duration on native plants and their associated food webs are poorly known. Specifically, while some studies have examined the effects of nutrient subsidies on native ecosystems for a single year (a nutrient pulse), repeated introductions of nutrients across multiple years (a nutrient press) better reflect the persistent nature of anthropogenic nutrient enrichment. We therefore contrasted the effects of a one-year nutrient pulse with a four-year nutrient press on arthropod consumers in two salt marshes. Salt marshes represent an ideal system to address the differential impacts of nutrient pulses and presses on ecosystem and community dynamics because human development and other anthropogenic activities lead to recurrent introductions of nutrients into these natural systems. We found that plant biomass and %N as well as arthropod density fell after the nutrient pulse ended but remained elevated throughout the nutrient press. Notably, higher trophic levels responded more strongly than lower trophic levels to fertilization, and the predator/prey ratio increased each year of the nutrient press, demonstrating that food web responses to anthropogenic nutrient enrichment can take years to fully manifest themselves. Vegetation at the two marshes also exhibited an apparent tradeoff between increasing %N and biomass in response to fertilization. Our research emphasizes the need for long-term, spatially diverse studies of nutrient enrichment in order to understand how variation in the duration of anthropogenic nutrient subsidies affects native ecosystems.
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影响因子：
4
作者：
Howarth, RW;Billen, G;Zhu, ZL
通讯作者：
Zhu, ZL
影响因子：
4.8
作者：
Clark, JS
通讯作者：
Clark, JS
影响因子：
2.9
作者：
Huxel, GR;McCann, K
通讯作者：
McCann, K
DOI：
10.1073/pnas.022447299
发表时间：
2002-02-05
影响因子：
11.1
作者：
Bertness, MD;Ewanchuk, PJ;Silliman, BR
通讯作者：
Silliman, BR
影响因子：
4
作者：
Mayer, B;Boyer, EW;Paustian, K
通讯作者：
Paustian, K