An interview with biologist Dr. Patricia Chow-Fraser

Dr. Patricia Chow-Fraser is a Professor of Biology at McMaster University in Ontario, Canada, where she studies the ecology, conservation and restoration of aquatic ecosystems. Her fieldwork – conducted primarily in the coastal zones of the Laurentian Great Lake region – seeks to monitor and predict the long-term impact of human activities on ecosystem health. In addition to physical sampling, Patricia’s lab also makes use of satellite data to track environmental change, wetland connectivity and habitat loss.

A JMP user for more than 30 years, Patricia spoke with User Reference Manager Meg Hermes about her research.

Meg: Let’s start by talking about some of the central questions motivating your research.

Patricia: We develop and use ecological indicators to assess the impact of human activities, such as urban, agricultural and recreational development and climate change, on the long-term health of wetlands and streams in the Great Lakes basin. The ecological indicators are based on biotic communities, including wetland plants, zooplankton, fish, amphibians and turtles, as well as abiotic variables such as water quality, hydrogeomorphy and habitat integrity.

Meg: What, in your opinion, is the most common misconception you encounter in ecology today?

Patricia: A common misconception is that wetlands are wastelands and that they need to be drained to be transformed into useful land. Another I have encountered is that wetlands can be created and/or restored back to their original health and functionality. Most wetlands cannot be restored – the best we can do is rehabilitate them.

Meg: Tell me about your research methods. What kinds of data do you collect?

Patricia: We collect many types of physico-chemical data – temperature, dissolved oxygen or conductivity, for example – with vertical profiling sondes, as well as samples of nutrient data from wetlands, lakes and streams, typically spanning multiple years or decades. We also have biotic datasets on abundances and richness of fish, benthic invertebrates, birds, amphibians, as well as percent cover of macrophyte and terrestrial vegetation.

For use in geographic information systems, we collect radio telemetry data of fish and turtles to determine their movements, home ranges and habitat uses. We often tap archived public long-term data sets to use in various research projects.

Meg: What are some of the biggest data challenges you encounter in doing this kind of work?

Patricia: Typically, the environmental data sets are large and messy. The format of publicly archived data sets requires pre-processing and manipulations to render them usable. The data do not tend to meet the assumptions of parametric tests and must therefore be transformed before we can use parametric tests, or often, we use non-parametric tests instead. Producing publishable graphs for these large data sets is also a challenge.

Meg: What’s a typical data workflow like?

Patricia: Often our first step involves joining biotic and abiotic data sets by station ID and date. Most data start off in Excel and the date fields are entered in various formats. We have to standardize the date format and ensure the site name is identical in all data sets before we join them. We sometimes have to split the test values by the tests before we can conduct multivariate analyses. Such pre-processing and manipulations are sometimes performed on data sets with millions of rows and dozens of columns.