Condition of rocky reef communities around Tasmania: algal surveys

The data is the percent algal cover 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 and megafaunal invertebrate abundance 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站点采用样带计数法开展水下视觉普查（underwater visual census, UVC）所得的藻类盖度百分比数据。该数据隶属于一套更大的数据集，后者还针对该区域开展了鱼类及大型无脊椎动物丰度调查。整合后的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——首次普查于1992至1995年间开展，后续于2006至2007年在相同站点复勘，目前仍有持续普查的规划。
后续研究新增了一项船坡道相关子研究，旨在探究船坡道的空间分布及其对捕捞活动的影响。本研究针对塔斯马尼亚周边133处浅海岩礁站点的鱼类及大型无脊椎动物（鲍鱼与岩龙虾）水下视觉普查数据展开分析，这些站点距最近船坡道的距离介于0.6至131千米之间。本次分析的站点并非全部与1994年及2006年岩礁群落对比研究所用站点重合。
本次子研究所分析的133处站点，仅包含以两种主要藻类（海带类）群——昆布目（laminarian）或墨角藻目（fucoid）为优势类群的站点。2006年共普查196处站点，其中藻类群落非典型的站点被排除在外。
本研究旨在分析岩礁群落数据，以探究群落层面的变化、物种丰富度与外来物种种群的变化，以及可能由海洋变暖与捕捞活动引发的群落变迁。
相关方法细节已在Edgar与Barrett（1997）的研究中详述。本数据集主要源自各调查站点5米水深及/或10米水深处的样带采集数据。本次岩礁群落普查所采用的水下视觉普查方法，旨在最大化实现以下三类监测目标：（1）种群数量与体型结构的变化；（2）捕捞等扰动所引发的生态系统级联效应；（3）岩礁群落的长期变化与波动。