Marine reserves demonstrate top-down control of community structure on temperate reefs
Marine reserves demonstrate top-down control of community structure on temperate reefs
复制标题
海洋保护区展示了对温带珊瑚礁群落结构的自上而下的控制
作者：
N. Shears;R. Babcock
抽象的。在海洋保护区和相关的未受保护地区进行重复的生态研究，对于审查捕鱼对社区的自上而下的影响和生态系统层面的影响很有价值。我们进行了实验研究，在两个温带海洋保护区，以研究这些自上而下的影响浅潮下带礁群落在新西兰东北部。这两个储备检查是已知的，以支持高密度的捕食者和拴系实验表明，捕食的机会占主导地位的海胆，Evechinus chloroticus，在这两个储备是约7倍，相对于外面。捕食是最激烈的最小尺寸类（30-40毫米）的拴系海胆，海胆的大小不再表现出神秘的行为。大海胆的捕食比例很高，可以归因于多刺龙虾，Jasus edwardsii。捕食较小的类可能是由龙虾和掠食性鱼类，主要是sparid Pagrus auratus。成年Evechinus积极放牧的海胆贫瘠的栖息地的底层密度被发现是显着较低的海洋保护区网站（2.2±0.3 m-2）相对于非保护区网站（5.5±0.4 m-2）。保护区和非保护区的隐幼鱼密度没有差异。储备人口更双峰，与海胆之间的40和55毫米发生在非常低的数字。实验去除Evechinus从海胆贫瘠的栖息地超过12个月，导致从甲壳珊瑚藻栖息地的变化，以大型藻类为主的栖息地。这样的大型藻类栖息地被认为是更广泛的两个储备，海胆密度较低，相对于邻近的未受保护的地区，主要是海胆贫瘠。所观察到的模式提供了证据的捕食者在构建浅礁社区在新西兰东北部的自上而下的作用，并展示了海洋保护区如何可以扭转渔业的间接影响，并重新建立社区一级的营养级联。
Abstract. Replicated ecological studies in marine reserves and associated unprotected areas are valuable in examining top-down impacts on communities and the ecosystem-level effects of fishing. We carried out experimental studies in two temperate marine reserves to examine these top-down influences on shallow subtidal reef communities in northeastern New Zealand. Both reserves examined are known to support high densities of predators and tethering experiments showed that the chance of predation on the dominant sea urchin, Evechinus chloroticus, within both reserves was approximately 7 times higher relative to outside. Predation was most intense on the smallest size class (30–40 mm) of tethered urchins, the size at which urchins cease to exhibit cryptic behaviour. A high proportion of predation on large urchins could be attributed to the spiny lobster, Jasus edwardsii. Predation on the smaller classes was probably by both lobsters and predatory fish, predominantly the sparid Pagrus auratus. The density of adult Evechinus actively grazing the substratum in the urchin barrens habitat was found to be significantly lower at marine reserve sites (2.2±0.3 m–2) relative to non-reserve sites (5.5±0.4 m–2). There was no difference in the density of cryptic juveniles between reserve and non-reserve sites. Reserve populations were more bimodal, with urchins between 40 and 55 mm occurring at very low numbers. Experimental removal of Evechinus from the urchin barrens habitat over 12 months lead to a change from a crustose coralline algal habitat to a macroalgal dominated habitat. Such macroalgal habitats were found to be more extensive in both reserves, where urchin densities were lower, relative to the adjacent unprotected areas that were dominated by urchin barrens. The patterns observed provide evidence for a top-down role of predators in structuring shallow reef communities in northeastern New Zealand and demonstrate how marine reserves can reverse the indirect effects of fishing and re-establish community-level trophic cascades.