Centre for Research on Ecological Impacts of Coastal Cities, School of Biological Sciences, Marine Ecology Laboratories A11, University of Sydney, New South Wales 2006, Australia.
Ecol Appl. 2011 Mar;21(2):427-38. doi: 10.1890/09-1940.1.
A major challenge in ecology is to understand and predict consequences of environmental changes to biological assemblages. Urbanization and associated alteration and destruction of habitat cause profound changes in local biodiversity and the ecology of and interactions among organisms. This study tested hypotheses about interactions among intertidal species on urbanized shores to examine predictions from their known ecology. On natural shores, grazing limpets, Cellana tramoserica, outcompete the smaller limpets, Patelloida latistrigata. The latter shelter among barnacles. On seawalls in Sydney Harbour (Australia), P. latistrigata were found among and on oysters. C. tramoserica were found directly on walls where there were no oysters. To explain these observations, several models were proposed and tested by manipulative experiments in the field: (1) oysters provide habitat for P. latistrigata; (2) negative interactions with C. tramoserica cause P. latistrigata to move on and among oysters; and (3) in areas with oysters, space available for grazing is insufficient for C. tramoserica to survive well. The results showed that C. tramoserica had a negative impact on the survival of P. latistrigata, although not causing the latter to move onto oysters. The oysters directly and indirectly affected P. latistrigata. First, oysters provided habitat and increased survival of P. latistrigata. Second, oysters influenced the interaction between C. tramoserica and P. latistrigata. This "interaction modification" diminished the negative impact of C. tramoserica. The material used to construct a wall did not directly influence the distribution of the limpets. Maintaining oysters on seawalls is, however, important because of their direct and indirect effects on P. latistrigata. It was possible to predict some processes on urbanized shores from known ecology. Other processes could not be predicted, making it necessary to do experiments to understand how built structures influence biological assemblages. This research contributes to understanding how to conserve biodiversity in urban areas.
生态学的一个主要挑战是理解和预测环境变化对生物组合的影响。城市化以及由此导致的栖息地的改变和破坏，会对当地生物多样性以及生物之间的生态关系和相互作用产生深远的影响。本研究通过检验有关城市化海岸带生物相互作用的假说，来检验从已知生态学中得出的预测。在天然海岸上，掠食性贻贝 Cellana tramoserica 会与体型较小的贻贝 Patelloida latistrigata 竞争，而后者则栖息在藤壶之间。在澳大利亚悉尼港的防波堤上，发现 P. latistrigata 栖息在牡蛎之间和牡蛎上。而 C. tramoserica 则直接在没有牡蛎的防波堤上被发现。为了解释这些观察结果，提出了几个模型，并通过野外的操作性实验进行了检验：（1）牡蛎为 P. latistrigata 提供了栖息地；（2）与 C. tramoserica 的负相互作用导致 P. latistrigata 移动到牡蛎上和牡蛎之间；（3）在有牡蛎的区域，可供掠食的空间不足以让 C. tramoserica 生存。结果表明，C. tramoserica 对 P. latistrigata 的生存有负面影响，尽管不会导致后者移动到牡蛎上。牡蛎直接和间接地影响了 P. latistrigata。首先，牡蛎为 P. latistrigata 提供了栖息地，并提高了其存活率。其次，牡蛎影响了 C. tramoserica 和 P. latistrigata 之间的相互作用。这种“相互作用的改变”减轻了 C. tramoserica 的负面影响。用于建造防波堤的材料不会直接影响贻贝的分布。然而，由于牡蛎对 P. latistrigata 的直接和间接影响，在防波堤上保留牡蛎是很重要的。从已知的生态学中可以预测一些城市化海岸带的过程。而其他过程则无法预测，因此需要进行实验以了解建筑结构如何影响生物组合。本研究有助于理解如何在城市地区保护生物多样性。
