Once you have collected the data from the field you need to work out what the numbers are telling you – so how do we analyse this data? This episode runs through the processes of calculating percentage cover and creating a graph. These calculations are important to help communicate to yourself and others how serious the impact of weeds is on your local riparian zone.

Save Our Catchment – Episode 10

WARNING – Aboriginal and Torres Strait Islander viewers are warned that the following video may contain images and voices of deceased persons.

Melissa – Once you've collected data in the field, what do you do with it? You will probably have ended up with figures written down on a page for each location. Now you need to record the data formally and present it in a way that helps identify any patterns or trends. The role of our field work is to assist local Landcare managers in targeting locations for Cat's Claw Creeper management.

In this episode, you'll be learning how to conduct data analysis, calculate average percentage cover, present data in the right choice of graph, identify patterns in the data. Once you have gathered your results, you need to calculate the average percentage cover at each location.

Step one, draw out or design a results table and record all of your raw data into it. This makes it nice and clear to calculate your average percentage cover from each location. You should now complete your data table.

Step two, calculate an average for each location. You should have 10 percentages along the 10 metre transect for location one. Add up the 10 figures you have and divide this figure by 10. This will summarise the percentage cover of Cat's Claw Creeper for one location and give you an overall picture of what is happening at that target location. Calculate the average for location two and three along the Clarence River. Record the average figures in your results table.

Why should we calculate the average percentage cover for each location? The three average percentage cover figures allow for an easy comparison between the different locations to enable Landcare managers to decide which place is in need of urgent environmental management.

You are learning about the geography of the Clarence River. But these skills are also linked with what you learn in science. In science and geography, it is a skill to decide whether you draw a line or column graph, depending on the variables you are using. As the data we have collected has been from three separate locations, it is known as a discontinuous variable. This means the data should be presented as a bar graph.

You can draw out a graph using pencil and a ruler on graph paper or create one on your computer using Excel or Google Sheets. You should plot average percentage cover on the Y axis, vertical, and location one, two, and three on the X axis, horizontal. Make sure your scale is easy to read. You should also label each axis clearly and include units where appropriate. The graph gives an easy overall view of the distribution of Cat's Claw Creeper at three locations.

Identify patterns in the data. This may need to be done after the data collection. There are a variety of ways we can use the information we have collected in the field. After identifying differences in distribution of species in two areas, you can develop a hypothesis that might explain the differences in distributions. Questions that may be considered in the future could include, one, is there a difference in distribution of the Cat's Claw Creeper at depositional sites and removal, erosion, sites? Or two, how far inland in the riparian zone are the infestations spreading? Or number three, why does the Cat's Claw Creeper occupy certain areas and not others?

By completing this field work we are maintaining a database. The information can be kept over a number of years to assist Landcare managers in their decision making in regards to control measures and management in the Upper Clarence catchment.

List of sources and acknowledgements:

  1. Video – Drone Footage of The Everlasting Swamp. We would like to thank The Everlasting Swamp National Park and Jessica Robertson Photography and Design for contributing their beautiful drone footage
  2. Narration – Voice over by Melissa Ellis, Southern Cross School of Distance Education
  3. Acknowledgment – We wish to thank Father Pop Harry Walker, Annabelle Walker, Roy Bell, Jubullum Local Aboriginal Land Council, Steve Walker, Marty Walker, David Foley, Upper Clarence River Landcare, Terry Moody, Steven Ross, Frederick Ellis

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