Unexpected patterns of facilitatory grazing revealed by quantitative imaging
Unexpected patterns of facilitatory grazing revealed by quantitative imaging
复制标题
定量成像揭示了意想不到的便利放牧模式
DOI：
10.3354/meps07302
复制
发表时间：
2008
影响因子：
2.5
通讯作者：
R. Murphy
中科院分区：
文献类型：
--
作者：
A. Underwood;R. Murphy
微藻（潮间带腹足类的主要食物）进行了量化的潮间带螺Nerita atramentosa的中海岸避难所周围地区的假设，即删除重要的食草动物会导致更多的微藻。数字彩色红外图像提供了对小区域内叶绿素数量（作为微藻数量指数）的独立定量测量。为了确定放牧对微藻丰度的影响，使用笼子将动物排除在避难所之外。其他的避难所没有笼子，或者只有部分的对照笼子。与预测相反，在避难所附近的微藻数量，N。在不含N. atramentosa的条件下，N. atramentosa对微藻生长或存活的影响。促进作用的发生可能是由于帽贝Cellana tramoserica的放牧减少，其中N。atramentosa（竞争优势）的存在或N. atramentosa直接对微藻。要解开复杂的生态相互作用，涉及放牧周围的避难所和放牧对生态结构和功能的影响，有必要通过时间进行重复的，独立的测量。遥感提供了使用传统方法难以或不可能获得的有关粮食分配的信息。这项研究确定了复杂性和相互作用，对许多陆地，潮间带和海洋栖息地的放牧影响的研究。
Micro-algae (the principal food of intertidal gastropods) were quantified in areas surrounding mid-shore refuges of the intertidal snail Nerita atramentosa to test the hypothesis that removal of important grazers would lead to more micro-algae. Digital colour-infrared imagery provided independent quantitative measurements of amounts of chlorophyll (as an index of amounts of micro-algae) over small areas through time. To determine the effect of grazing on micro-algal abundance, cages were used to exclude animals from refuges. Other refuges were left uncaged or had partial, control cages. Contrary to predictions, amounts of micro-algae in areas close to refuges from which N. atramentosa had been excluded were smaller than in controls, suggesting facilitatory effects of N. atramentosa on micro-algal growth or survivorship. Facilitation may occur because of decreased grazing by the limpet Cellana tramoserica where N. atramentosa (a competitive dominant) are present or to facilitatory effects of N. atramentosa directly on the micro-algae. To unravel complex ecological interactions involving grazing around refuges and the impact of grazing on ecological structure and function it is necessary to make repeated, independent measurements through time. Remote-sensing provided information on distribution of food that would be difficult or impossible to achieve using conventional methods. This research identified complexities and interactions that have implications for the study of grazing effects across many terrestrial, intertidal and marine habitats.