July 2018 Muskoka REPORT Watershed www.muskokawatershed.org Muskoka Watershed Report Card Council BACKGROUND 2018 Muskoka Watershed Report Card Background Report Table of Contents List of Figures ............................................................................................................................................... 3 List of Tables ................................................................................................................................................ 4 Acknowledgements ...................................................................................................................................... 5 Muskoka Watershed Council ................................................................................................................... 5 The District Municipality of Muskoka ....................................................................................................... 5 Key Scientific Advisors ............................................................................................................................... 5 Contributors ................................................................................................................................................ 6 Data Sources .............................................................................................................................................. 6 Letter from the Chair ..................................................................................................................................... 7 Glossary of Key Terms .................................................................................................................................... 8 State of the Muskoka Watershed ................................................................................................................ 9 Introduction .................................................................................................................................................. 10 Goal ........................................................................................................................................................... 10 Objective .................................................................................................................................................. 11 Rationale ................................................................................................................................................... 11 The ‘Muskoka Watershed’ ...................................................................................................................... 12 The Muskoka River Watershed (2EB) ..................................................................................................... 14 The Black-Severn River Watershed (2EC) ............................................................................................. 15 Watershed use.......................................................................................................................................... 16 Past indicators of watershed health ..................................................................................................... 16 2018 Muskoka Watershed Report Card indicators ............................................................................. 17 Watershed grades ................................................................................................................................... 18 Calcium Concentrations in Muskoka’s Lakes ......................................................................................... 21 What is calcium and why is it important in Muskoka? ....................................................................... 21 Acid rain and calcium ............................................................................................................................ 21 Ecological impacts of low calcium ...................................................................................................... 22 How is calcium measured in Muskoka? ............................................................................................... 22 Results ........................................................................................................................................................ 23 What do the results mean? .................................................................................................................... 29 It’s your turn!.............................................................................................................................................. 31 Phosphorus Concentrations in Lakes ........................................................................................................ 32 What is phosphorus and why is it important in Muskoka? ................................................................. 32 Trophic status in Muskoka’s lakes .......................................................................................................... 32 How is Phosphorus measured in Muskoka? ......................................................................................... 34 About R2 values, trend lines (linear regression), and p-values .......................................................... 35 1 2018 Muskoka Watershed Report Card Background Report Results ........................................................................................................................................................ 35 What do these results mean? ................................................................................................................ 42 It’s your turn!.............................................................................................................................................. 43 Benthic Macroinvertebrates ...................................................................................................................... 44 What are benthos and why are they important in Muskoka? .......................................................... 44 Why do we sample for benthic macroinvertebrates? ...................................................................... 44 How are benthos measured in Muskoka? ........................................................................................... 45 Data analysis ............................................................................................................................................ 46 Results ........................................................................................................................................................ 47 What do these results mean? ................................................................................................................ 51 It’s your turn!.............................................................................................................................................. 52 Interior Forest ................................................................................................................................................ 53 What is interior forest and why is it important in Muskoka? ............................................................... 53 Forest types in Muskoka .......................................................................................................................... 54 Threats to Muskoka’s forests ................................................................................................................... 55 How is interior forest measured in Muskoka? ....................................................................................... 55 Results ........................................................................................................................................................ 56 What do these results mean? ................................................................................................................ 57 It’s your turn!.............................................................................................................................................. 57 Invasive Species Reports in Muskoka ....................................................................................................... 59 What are invasive species and why are they important in Muskoka? ........................................... 59 How are invasive species measured Muskoka? ................................................................................. 61 Results ........................................................................................................................................................ 62 What do these results mean? ................................................................................................................ 65 It’s your turn!.............................................................................................................................................. 65 Species at Risk in Muskoka ......................................................................................................................... 66 What are species at risk and why are they important in Muskoka? ................................................ 67 Species at Risk in Muskoka ..................................................................................................................... 67 It’s your turn!.............................................................................................................................................