Development of benthic sampling methods for the Coral Reef Assessment and Monitoring Program (CRAMP) in Hawai'i
Development of benthic sampling methods for the Coral Reef Assessment and Monitoring Program (CRAMP) in Hawai'i
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DOI：
10.1353/psc.2004.0013
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发表时间：
2004-04-01
期刊：
影响因子：
0.7
通讯作者：
Hultquist, Jonathan
中科院分区：
文献类型：
--
作者：
Brown, Eric;Cox, Evelyn;Hultquist, Jonathan
夏威夷的珊瑚礁评估和监测方案于1998年设立，以监测全州珊瑚礁底栖生物群落的长期变化。该方法的开发涉及对夏威夷以前监测项目的结果进行分析，以确定各种方法检测变化的精度和统计能力。进行了额外的田间试验，以检查因素，如重复性，适当的样带长度，样带数量，每个样带的样本数量，覆盖估计技术，观察员的变化，以及时间和财政限制。以前在夏威夷使用的海底监测方法一般显示，由于精确度低和样本量小，检测变化的统计能力较低。田间试验表明，使用样条或样方的传统技术的重复性具有很高的变异性，因此统计能力低，除非努力重新定位采样单位，更精确。较长的横断面（例如，25和50 m）的变异性高于较短的样带（例如，10米），这表明较小的采样单位更适合于生境采样。与其他误差来源相比，分析相同数据的观察员之间的变异性较低。视觉估计技术显示初始成本较低，但根据调查效率较低。数字视频需要最高的初始资金投资，但每次调查产生的数据量最大，质量足够。与其他技术相比，数字视频方法的成本效益随着调查次数的增加而增加，并且在发生后勤费用的更偏远的情况下。栖息地内分层随机抽样设计实施的CRAMP设计。固定样带的选择，以减少时间方差，并允许有效的复测下的高波能场条件下，通常发现在夏威夷。该方法的目的是检测底栖生物覆盖的10%的绝对变化，具有高统计功效，每帧50个点，每样带20-30帧，每深度8-10样带。固定的照片样方与高精度和高分辨率的设计，允许详细监测珊瑚/藻类的生长，招聘和死亡率。
The Coral Reef Assessment and Monitoring Program (CRAMP) of Hawaii was established in 1998 to monitor long-term changes in coral reef benthic communities around the state. Development of the methodology involved analysis of results from previous monitoring programs in Hawaii to determine precision and statistical power of various methods to detect change. Additional field trials were conducted to examine factors such as repeatability, appropriate transect length, number of transects, number of samples per transect, cover estimation techniques, observer variation, as well as time and financial constraints. Benthic monitoring methods used previously in Hawaii generally showed low statistical power for detecting change due to low precision and small sample size. Field trials indicated that repeatability of conventional techniques using transects or quadrats had high variation and consequently low statistical power unless efforts were made to reposition the sampling units with greater precision. Longer transects (e.g., 25 and 50 m) had higher variability than shorter transects (e.g., 10 m), suggesting that smaller sampling units were more appropriate for the habitats sampled. Variability among observers analyzing the same data was low in comparison with other sources of error. Visual estimation techniques showed low initial cost but were inefficient per survey. Digital video required the highest initial monetary investment but yielded the greatest quantity of data per survey with sufficient quality. The cost effectiveness of the digital video method compared with other techniques increased with more surveys and in more remote situations where logistical expenses were incurred. A within-habitat stratified random sampling design was implemented for the CRAMP design. Fixed transects were chosen to reduce temporal variance and allowed efficient resurveying under the high-wave-energy field conditions typically found in Hawaii. The method was designed to detect an absolute change of 10% in benthic cover with high statistical power using 50 points per frame, 20-30 frames per transect, and 8-10 transects per depth. Fixed photo-quadrats with high precision and high resolution were included in the design to allow detailed monitoring of coral/algal growth, recruitment, and mortality.