Condition of rocky reef communities around Tasmania: invertebrate surveys

The data is the quantitative abundance of megafaunal invertebrates derived from underwater visual census methods involving transect counts at rocky reef sites around Tasmania. This data forms part of a larger dataset that also surveyed fish abundance and algal cover for the area. The aggregated dataset allows examination of changes in Tasmanian shallow reef floral and faunal communities over a decadal scale - initial surveys were conducted in 1992-1995, and again at the same sites in 2006-2007. There are plans for ongoing surveys.

An additional component was added in the latter study - a boat ramp study looking at the proximity of boat ramps and their effects of fishing. We analysed underwater visual census data on fishes and macroinvertebrates (abalone and rock lobsters) at 133 shallow rocky reef sites around Tasmania that ranged from 0.6 - 131 km from the nearest boat ramp. These sites were not all the same as those used for the comparison of 1994 and 2006 reef communities. The subset of 133 sites examined in this component consisted of only those sites that were characterized by the two major algal (kelp) types (laminarian or fucoid dominated). Sites with atypical algal assemblages were omitted from the 196 sites surveyed in 2006.

This study aimed to examine reef community data for changes at the community level, changes in species richness and introduced species populations, and changes that may have resulted from ocean warming and fishing.

The methods are described in detail in Edgar and Barrett (1997). Primarily the data are derived from transects at 5 m depth and/or 10 m depth at each site surveyed. The underwater visual census (UVC) methodology used to survey rocky reef communities was designed to maximise detection of (i) changes in population numbers and size-structure (ii) cascading ecosystem effects associated with disturbances such as fishing, (iii) long term change and variability in reef assemblages.

本数据集为塔斯马尼亚周边岩礁生境采用样带计数法开展水下视觉普查所得的大型无脊椎动物定量丰度数据。该数据集隶属于一项更大规模的综合数据集，后者还针对该区域开展了鱼类丰度与藻类覆盖度调查。整合后的完整数据集可用于分析塔斯马尼亚浅海岩礁动植物群落的十年尺度变化——首次调查于1992-1995年间启动，2006-2007年又在同一调查点位重复开展，且目前已有持续开展后续调查的计划。

后续研究新增了一项额外模块——船用坡道调查，旨在探究船用坡道的空间邻近性及其对捕捞活动的影响。我们针对塔斯马尼亚周边133个浅海岩礁生境的鱼类与大型无脊椎动物（鲍鱼及岩龙虾）水下视觉普查数据展开分析，这些调查点位距最近船用坡道的距离介于0.6至131千米之间。本次分析所用的站点与1994年和2006年岩礁群落对比研究所用的点位并非完全重合。本模块所分析的133个站点子集，仅包含以两类主要藻类（海带类）——海带目（Laminariales）或墨角藻目（Fucales）占优——为特征的调查点位。2006年共完成196个站点的调查，其中藻类群落非典型的点位被排除在本次子集之外。

本研究旨在通过岩礁群落数据分析，探究群落层面的结构变化、物种丰富度与外来物种种群的动态变化，以及可能由海洋变暖和捕捞活动引发的各类群落改变。

相关研究方法的详细说明详见Edgar与Barrett（1997）的研究成果。本次数据主要来源于各调查站点5米水深及/或10米水深处的样带采集。本次用于岩礁群落调查的水下视觉普查（Underwater Visual Census, UVC）方法，其设计目标是最大化实现以下三类监测目标：(i) 种群数量与体型结构的变化；(ii) 与捕捞等人为干扰相关的生态系统级联效应；(iii) 岩礁群落的长期变化与时空波动。