An experimental test of the effects of productivity and environmental stress on a rocky intertidal food web

生产力和环境压力对岩石潮间带食物网影响的实验测试

• 批准号: 13640622
• 负责人: NODA Takashi
• 金额: $ 2.24万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640622/
• 关键词: Foodweb; productivity; environmental stress; intertidal rocky store; top-down control; bottom-up control; field experiment; indirect effects; 野外操作実験

Food web dynamics can be controlled by both external factors of primary productivity and environmental stress of ecosystem. However, little is know about how these two factors affect the food web dynamics in natural communities. Here I report a field factorial experiment manipulating the nutrient levels (as an external factor controlling primary productivity), and desiccation stress (as a factor of envilonmental stress), and the presence /absence of macrograzer (limpets ; their grazing is a key process in the food web) in a rocky intertidal algae-grazer food web. The results revealed that desiccation stress and nutrient availability independently influenced the food web dynamics, and their effects occurred without modifying the limpet top-down effect. Desiccation stress directly reduced only foliose algae, and consequently increased competitive inferior filamentous algae and reduced mesograzers (amphipods) through a reduction in food and refuges from desiccation stress. High nutrient availability caused the increase of both filamentous and foliose algae, and consequently caused increase of mesograzers (amphipods). These results suggest that the both nutrient availability and desiccation stress affected the food web dynamics not via top-down process but via bottom-up process, and supported not environmental stress hypothesis but exploitative ecosystem hypothesis.

粮食网动态受初级生产力外部因子和生态系统环境压力的双重控制。然而，人们对这两个因素如何影响自然群落的食物网动态知之甚少。在这里，我报告了一个现场因子实验，操纵营养水平（作为控制初级生产力的外部因素），干燥压力（作为环境压力的一个因素），以及大型食草动物（帽贝，它们的放牧是食物网的关键过程）在潮间带岩石藻类食草动物食物网中的存在/缺失。结果表明，干旱胁迫和养分有效性对食物网动态具有独立的影响，且其影响不影响帽贝自上而下的效应。干燥胁迫只直接减少了叶藻，从而增加了竞争性的劣质丝状藻类，并通过减少食物和躲避干燥胁迫的庇护所而减少了中食草动物（片脚类）。高养分有效性导致丝状藻和叶状藻的增加，从而导致中食草动物（片足类）的增加。上述结果表明，养分有效性和干旱胁迫对食物网动态的影响不是自上而下的，而是自下而上的，支持的不是环境胁迫假说，而是生态系统剥削假说。