Nutrients induce and herbivores maintain thallus toughness, a structural anti-herbivory defense in Turbinaria ornata
Nutrients induce and herbivores maintain thallus toughness, a structural anti-herbivory defense in Turbinaria ornata
复制标题
营养物质诱导和食草动物维持叶状体的韧性，这是Turbinaria ornata的一种结构性反食草防御
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
P. Fong
中科院分区：
文献类型：
--
作者：
J. Bergman;B. N. Dang;M. Tabatabaee;M. McGowan;C. R. Fong;S. J. Bittick;P. Fong
珊瑚覆盖的丧失，经常是由人为干扰造成的，可能导致肉质大型藻类的阶段性转变，其中许多含有抗草食动物的防御。利用实地调查，围隔实验，和实地实验，我们评估了是否2人类的影响-营养丰富和减少草食动物-影响生产和维护的叶状体韧性，物理防御的棕色macrophora Turbinaria ornata，最近扩大了整个南太平洋。与我们的预期相反，草食性鱼类丰度和叶状体韧性之间存在弱的负相关关系。这种关系是由更大的韧性藻类收集在更富营养化的网站，这也有较低的食草动物丰度。围隔实验证实了营养物质和叶状体韧性之间的正相关关系，没有可测量的成本增长。机械损伤模拟草食动物保持叶状体韧性在笼子里，与一个显着的权衡增长。此外，减少植食动物通过笼在移植实验中导致减少叶状体韧性，但是没有可测量的增长的好处，可能是由于同时发生的变化，从移植的环境背景。虽然通过过度捕捞减少草食动物，使这一贸易的能量通常花在国防增加增长，营养丰富提供T。装饰与额外的资源，以增加防御。随着人为影响在珊瑚礁系统中变得越来越突出，我们必须了解可能促进珊瑚礁藻类的扩张和主导地位的过程，特别是那些具有诱导性抗草食动物防御的过程。
The loss of coral cover, frequently driven by anthropogenic disturbances, can result in a phase shift to dominance by fleshy macroalgae, many of which contain anti-herbivore defenses. Using field surveys, a mesocosm experiment, and field experiments, we evaluated whether 2 human impacts — nutrient enrichment and reduction in herbivory — affected production and maintenance of thallus toughness, a physical defense of the brown macroalga Turbinaria ornata that has recently expanded across the South Pacific. In contrast to our expectations, there was a weak negative relationship between herbivorous fish abundance and thallus toughness. This relationship was driven by greater toughness in algae collected at the more eutrophic sites, which also had lower herbivore abundances. A mesocosm experiment confirmed a positive relationship between nutrients and thallus toughness with no measurable cost to growth. Mechanical damage simulating herbivory maintained thallus toughness in cages, with a significant trade-off in growth. In addition, reduction of herbivory through caging in a transplant experiment resulted in a reduction in thallus toughness; however there was no measurable benefit to growth, possibly due to a concurrent change in environmental context from the transplant. While reduction in herbivory via overfishing allows this alga to trade energy normally spent on defense for increase growth, nutrient enrichment provides T. ornata with additional resources to increase defenses. As anthropogenic impacts become increasingly prominent in coral reef systems, it is critical that we understand the processes that may facilitate the expansion and dominance of coral reef algae, especially those with inducible anti-herbivore defenses.