Testing the facilitation-competition paradigm under the stress-gradient hypothesis: decoupling multiple stress factors
Testing the facilitation-competition paradigm under the stress-gradient hypothesis: decoupling multiple stress factors
复制标题
DOI：
10.1098/rspb.2007.0871
复制
发表时间：
2007-10-07
影响因子：
4.7
通讯作者：
Tokeshi, Mutsunori
中科院分区：
文献类型：
--
作者：
Kawai, Takashi;Tokeshi, Mutsunori
虽然压力梯度假说下的促进竞争范式最近受到了关注，但其严格的测试还有待探索。大多数研究认为，随着环境压力的增加，净相互作用从竞争到促进的转变是支持这一假设的主要证据，但很少有研究考察相互作用沿着整个压力梯度的变化。在这里，我们已经概念化了相互作用强度沿着这种梯度的变化模式的可能变化。在此基础上，我们经验性地评估了两种海洋固着动物，鹅藤壶（Capitulum mitella）和贻贝（Septifer virgatus）之间的相互作用的时间转移，在多种应激因素。鹅藤壶对贻贝存活率的净效应与包括物理干扰和热应力两个应力因子的总应力梯度呈正相关，即使在温和的条件下也没有出现负值。当这两个应力因素分别处理，但是，净效应表现出明显不同的模式：单调增加与物理干扰与准渐近模式（在很宽的范围内没有变化）与热应力。这些变量的情况下，以前没有被认识到在这门学科，本研究强调的重要性，一个综合的和机械的方法来测试和破译的促进竞争范式。
While the facilitation-competition paradigm under the stress-gradient hypothesis has received recent attention, its rigorous testing is yet to be explored. Most of the studies have considered a switch in the net interactions from competition to facilitation with increasing environmental stress as primary evidence supporting the hypothesis, though few studies examined changes in interaction along a full range of a stress gradient. Here, we have conceptualized possible variations in the patterns of change in interaction strength along such gradient. Based on this, we empirically evaluated the temporal shift in the interaction between two marine sessile animals, goose barnacles (Capitulum mitella) and mussels (Septifer virgatus), under multiple stress factors. The net effect of goose barnacles on mussel survivorship was positively related to the total stress gradient encompassing two stress factors, physical disturbance and thermal stress, while no negative value occurred even under mild conditions. When the two stress factors were treated separately, however, the net effect demonstrated apparently different patterns: monotonic increase with physical disturbance versus a quasi-asymptotic pattern (no change over a wide range) with thermal stress. These variable situations have not previously been recognized in this discipline, and the present study emphasizes the importance of an integrative and mechanistic approach to testing and deciphering the facilitation competition paradigm.