Citizen science stands up to scrutiny in marine study

Diver and yellow butterfly fish
The volunteer methods detected after just five surveys the same number of species that it took 24 professional surveys to detect. In terms of finding out which species are present it seems to be the more flexible, preferable method.
Dr Ben Holt
Methods of data collection which employ citizen science can hold their own when compared to traditional scientific practices, according to the results of a
University of East Anglia-led study. The research, which has appeared in the journal Methods in Ecology and Evolution, focuses on volunteer data collection in a marine diversity context and has found that the areas where professional scientists have the upper hand are largely balanced out by the advantages of recruiting amateur citizen scientists.

The work juxtaposed a method used by volunteers in fish surveys such as those run by the Reef Environmental Education Foundation (REEF) – known as the ‘roving diver technique’ – with the ‘belt transect’ method more commonly used by professional researchers. It was carried out in conjunction with the Centre for Marine Resource Studies in the Turks and Caicos Islands, the University of Copenhagen and the Australian Institute of Marine Science.

Dr Ben Holt is a lecturer in UEA’s School of Biological Sciences and lead author of the paper. He began an interview with by explaining the motivations behind this research and discussing how the findings may impact on strategies and techniques used by future citizen science projects.

"In the case we were concerned with, thousands of people had collected well over a hundred thousand surveys of fish species across the Caribbean region and beyond," he said. "As a scientist interested in studying patterns of biodiversity in all sorts of species, citizen science seems like a very useful resource for data collection.

"The problem is that, as the dataset is volunteer-collected, there are various aspects that need to be checked because they could potentially introduce bias into a study. One of those aspects is the methodology used to collect the data. In order to encourage people to stick at it, volunteer organisations have to make sure that the collection process is fun, which doesn’t always go hand-in-hand with standardisation."

In order to test the reliability of the thousands of survey results obtained, Dr Holt and his colleagues designed a study to compare the method they had used with the more standardised professional method. Over a four week period, two teams of 12 divers surveyed 144 underwater sites. While the traditional method recorded 106 different species of fish, the citizen volunteer survey technique sighted 137 species in the same waters.

"According to our results, one clear difference between the two is that the volunteer methods find a lot more species and they do it more quickly," stated Dr Holt. "The volunteer methods detected after just five surveys the same number of species that it took 24 professional surveys to detect. In terms of finding out which species are present it seems to be the more flexible, preferable method."

On the other hand, the volunteer techniques tend not to be quite as consistent. It can be more difficult to detect an increase or decrease in species numbers over time or to compare two sites, for example, due to the larger amount of variability in results. However, on balance, Dr Holt reasoned that the pros and cons balance out and the methods are approximately as good as each other.

Although Dr Holt agreed that citizen science lends itself to research on biodiversity, it can be problematic from the researchers’ point of view that citizen science programmes are set up with the aim of encouraging participation rather than with a view to potential scientific outcomes. There are also other improvements that could be made, he suggested.

"There is not always the appropriate level of communication between us, as scientists, and the people going out and collecting the data," Dr Holt said. "I think we have a responsibility to improve that."

Volunteer schemes offer an opportunity for researchers to collect data on biodiversity across wide areas and get local-scale data, which is an extremely expensive and time-consuming process to carry out professionally. The case of the lionfish, which has invaded the Caribbean in the last ten years, is one in which volunteer divers have proved – and continue to prove – invaluable for monitoring distribution and populations. Dr Holt hopes that the findings of this study will increase confidence in the consistency and reliability of citizen science data.

"I’m certainly confident that it will have a positive impact on citizen science in the specific environment that we were looking at, for coral reef science," he stated. "There are a lot of programmes up and running, including the ones that collected data for this study and others such as Seasearch in the UK, which is very similar.

"How transferable our results are to the methods that other citizen science programmes use is open to question, but I’d like to think that the overall experimental we have designed could be useful to people trying to answer that question."

There are two other important questions that remain to be answered on the value of citizen science as compared to professional data collection, and they are also under consideration by Dr Holt and his colleagues.

"When using volunteer-collected data, you have a lot less control over who goes to which places, and that means that some places are surveyed an awful lot and other places not so much," he related. "If you simply use the raw numbers of species counted at particular points, it will be heavily influenced by the number of people having completed surveys. There are statistical methods for dealing with that kind of problem, but it must still be considered carefully."

Probably the most important challenge, however, and one which is equally applicable to professional scientists, is the impossibility of having the same people collect data at all of the different sites in such a large undertaking.

"There will be different people operating in different areas, and unless you have a good idea of the abilities of those people in terms of which species they can identify, it’s hard to tell how far your results are driven by that," continued Dr Holt. "There are ways and means of looking at it, but it’s something that needs to be considered by the people performing the surveys in the first place to try to standardise results as much as possible between people."



This is one reason why responsible caregivers need to be allowed to have these creatures - to stop them from becoming extinct; albeit in captivity only.

Commented Cheryl on
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