Project title: The effect of Climate Change on the river Dodders ecosystems.

Team: The River Dodder Detectives

Firhouse Road   Dublin 24   Ireland   20 Student’s age: 16-17 years old

How has Climate Change affected section 40 of the river Dodder’s ecosystem, using indicators such as pH, temperature, dissolved oxygen, presence of the Mayfly and Stonefly using Kick sampling?

We picked 6 sections of the river Dodder 40, to analyse and carried out the same tests,
every Friday at the same time for 3 weeks.
Using a pH meter, we recorded the pH of each section of the river.
Using a digital thermometer, we recorded the temperature of each section of the river.
Using sample jars, we collected water samples from each section and tested them for dissolved oxygen using a dissolved oxygen probe and recorded the results.
We carried out the Kick sampling test and recorded the invertebrates that were present on an excel sheet.
We contacted the Environmental Protection Agency, and they showed us how to access all their data, which included, all pH, temperature, and dissolved oxygen values from 2007 to 2022. It also included the percentage population of the Mayfly and Stonefly for the same period.
We contacted Inland Fisheries Ireland, and they took us out on a Field trip to the Dodder 40, they showed us how to do a Kick sampling test properly and using a key to identify the different invertebrate. Using electrofishing, they gave us the opportunity to hold and identify trout.
We also contacted the Dodder Anglers Committee, we interviewed a member of the committee, he explained the weather changes he has observed over the past 5 years, he also recommended several webinars to watch which contained vital information.
We watched webinars on the Annacotty Fish Passage Project, Hydromorphology, Climate Change and Barriers to fish migration in Ireland and recorded information applicable to our project.
Students researched the world wide web to understand why we are studying the variables, pH, temperature, dissolved oxygen, presence of Mayfly and Stonefly and how they related to the ecosystems of the river Dodder.

Data shows the period from 2007 to 2022 during the months of February and March, temperatures ranged from 3.3 to 9.1 °C and the average temperature for the same period was 6.2 °C whereas according to the results we recorded, the average temperature for the same months in 2023 was 8.33 °C, a significant increase.
The DO results we obtained ranged from 3.9mg/l to 4.83mg/l, incredibly low compared to previous years. The secondary data, shows DO ranges from 10mg/l to 16.3 mg/l during the same period, February to March, from 2007 to 2022 and the average DO level was 11.01 g/l.
The data indicates that there is a relationship between temperature and DO, as temperature increases, DO decreases.
We learned that barriers such as weirs are increasing the temperature of rivers. Section 40 of the Dodder has a weir at both ends. They are causing an increase in temperature, this was evident in Data collected in the summer of 2021, which shows that regulated rivers (with damns and weirs) are much warmer than free flowing rivers. Data shows the Dodder reached temperatures of over 20 °C at this time.
At these temperatures Salmonids stop feeding, become more distressed, and mortality is very high according to Anglers we interviewed. Projections show that during summer months we will see an increase in average temperature of 2.5 – 3°C.
It is evident from the data we collected that the Dodder’s ecosystems are being affected by Climate Change. The negative impacts observed are: increase in water temperature and pH, decrease in DO levels, and no recordings of the stonefly in 2022. Also only 4/11 species of Mayfly were present, of which only 1 – 5% of the very sensitive Baetida Mayfly present compared to 51 – 74% in 2005.
Limitations – small sample size, weather, resources, equipment, time, TY assignments and programs.

•We have learned that one of the biggest problems for the Dodders ecosystem is its structure, the presence of the weirs is increasing the temperature of the river and disrupting the lifecycle of salmonids. Because of the increase in temperature there has been a decrease in the DO levels.

•It is evident from the data we collected that the Dodders ecosystems are being affected by Climate Change. The negative impacts observed are, the increase in water temperature, decrease in DO levels, increase in pH, and no recordings of the stonefly in 2022, also 4 out of 11 species of Mayfly were present, of which only 1 – 5% of the very sensitive Baetida Mayfly present compared to 51 to 74% in 2005.

•To improve this investigation, we would examine the water every month to compare with previous data, examine the BOD, using a colorimeter we could test the quality of the water, recording the phosphate and nitrate levels.

•We are informing people of how important the Dodders ecosystems are. We plan to talk to South Dublin County Council to put up a plaque in the Dodder Valley Park to inform people how Climate Change is affecting them.

•We are campaigning to remove the weirs from the rivers so that the Dodder can return to its original state.
•We submitted an article to be published about our findings in the Echo newspaper and uploaded to the Dodder Anglers Website to increase communities’ awareness.

•We are encouraging the Dublin Counity Council to plant more trees alongside the river provide shade for the fish and cool the water. It will keep harmful nutrients from leaching into the Dodder.

•We have created our Website, sharing our project with the world.

https://karenscally7.wixsite.com/firhouse-community-c

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