A new approach to benthic biotope identification and mapping

• Main Author: Maher, Nicole Patricia
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2006
• Subjects: Biological oceanography; Ecology; Environmental science; Oceanography
• ISBN: 1109967373; 9781109967371

The overall goal of this study is to develop a reliable method for identifying and mapping benthic biotopes in aquatic systems based on both the geophysical characteristics of bottom sediments and the resident biotic communities. In contrast to traditional approaches to identify benthic habitats, this study relates benthic community data to the environmental variables using direct gradient analysis to reveal the variance in community structure that can be explained by these predictor variables. Acoustic mapping has been widely used to identify the extent and boundaries of sedimentary environments, but identification and mapping of benthic biotopes is still undeveloped. There are four main components to this project. First it is necessary to determine whether variables derived from geo-acoustic surveys are significantly related to the distribution of benthic faunal communities. The second component is to determine whether incorporating environmental variables from multiple scales (e.g., sediment grain-size measurements on the scale of centimeters, sediment-water profile images with variables on the scale of 10s of centimeters, and acoustic variables on the scale of 10s of meters) explains a significant amount of variance in community structure beyond that which can be explained by environmental variables at any single scale. The third element is to determine the best strategy for using acoustic texture variables from multibeam surveys for identifying and mapping soft sediment biotopes in coastal surveys. The ultimate component of this project is developing a method for combining the ability of classification techniques to identify discrete groups of samples with direct gradient ordination approaches to identify ecologically meaningful biotopes. I conclude by suggesting an efficient and parsimonious design for field studies that uses the geophysical data collected during a first stage of a study to direct subsequent environmental and faunal sampling. The ability to map biotopes over large spatial scales has great importance for the conservation and management of benthic faunal populations and the populations of animals that rely on them as a food source. This technique has the potential to transform the way that benthic survey studies are conducted.