MoRPh: a tool for assessing river habitats at biological monitoring sites

As you probably already know, SmartRivers is proud to be part of the Riverfly Partnership's 'Riverfly Plus' toolkit, alongside other exciting citizen science projects like MoRPh - the modular river survey

River organisms respond to their environment and so it is important to monitor any environmental changes. Often the environment is characterised through water chemistry and temperature, but the physical and hydraulic habitat structure of the river and its margins are also very important.

The MoRPh survey was developed to inventory habitats within a river channel and along its margins at a scale appropriate for characterising the physical environment at biological monitoring sites. Originally the biological monitoring was envisaged to be kick sampling of macroinvertebrate communities, and so MoRPh was designed to capture habitat within a rectangular area extending back 10 m across both river bank tops and along a length of river roughly equivalent to twice the river width. By conducting 10 adjacent MoRPh surveys along a river, a river length of approximately 20 channel widths is inventoried, which should be sufficient to capture the larger range of habitats available to more mobile species such as fish. I expect that both these scales are of interest to readers because invertebrates are food for fish!

The MoRPh survey records flow velocity patterns; sediments, including areas of siltation of the river bed; physical features such as pools, riffles, bars, bank profiles, ponds; the structure and extent of the river bed, edge and bank top vegetation; and the types of human interventions (pipes, weirs, bank reinforcement) and pressures from adjacent land use. These observations are recorded by not only ticking the type of feature that is present on a list but also by estimating the feature’s abundance through either a count (pools, riffles) or a category of percentage cover (gravel, vegetation structural type). There are three feature lists to complete, one for the bank tops, one for the bank faces and one for the river bed. In addition, the surveyor records details of where the survey is located, so that it can be shown on a map, and also the approximate size of the river channel, because river channel properties are strongly affected by river size.

MoRPh surveyors are allocated a log-in to an information system that stores and maps their data, calculates some useful indicators from their survey data, and allows raw data and indicators to be downloaded. The indicators include the degree of siltation, the average and largest sizes of the bed material, and the physical and vegetation complexity of the river bed. These bed-indicators are extremely useful for monitoring short-term (monthly, seasonal, annual) changes in the river bed that may impact on the invertebrate community. Broader changes in the river channel and its margins also have important impacts on river organisms but these changes usually occur more slowly, making monitoring most effective at an annual or longer timescale.

If you are interested in the MoRPh survey and would like to find out more, have a look at the Modular River Survey website: www.modularriversurvey.org.

- Prof. Angela Gurnell, Queen Mary University of London