Monitoring guidance for marine benthic habitats.

Abstract

Marine benthic monitoring programmes produce evidence against which to evaluate the cause and direction of change in the marine environment. They can also inform which management measures are appropriate, and determine whether they have been successful. It is crucial that monitoring programmes are well-designed and statistically robust to allow conclusions to be drawn from the acquired data. This ‘best-practice’ guidance aims to provide the information necessary to develop robust monitoring programmes that accurately identify change in the benthic environment. The guidance combines established ecological theory and protocols with JNCC advice and recommendations on benthic monitoring, by means of a step-wise framework which details key stages in the development of a monitoring programme. Whilst topics such as sample processing and equipment selection have been amply covered elsewhere, this guidance focuses on sampling design, drawing on frequentist theory. The basis of the framework is the development of monitoring objectives, following which the guidance addresses indicator selection, use of existing data, and temporal factors. The importance of statistical power and significance is explored, with guidance on the appropriate levels and ratios for different types of monitoring and the use of power analysis to determine the appropriate sample size. Dependency issues and sampling units are discussed, before guidance on sampling designs is provided. Finally, a statistical analysis section outlines various tests and analyses which can be performed to fulfil a range of monitoring objectives.