Something old, something new:

Transcription

1 Something old, something new: Curly-leaf pondweed and starry stonewort management Mike Verhoeven and Wes Glisson Larkin Lab

2 Response of starry stonewort (Nitellopsis obtusa) to control efforts in Lake Koronis, MN Wesley J. Glisson, Carli K. Wagner, Steven R. McComas, Kevin Farnum, Michael R. Verhoeven, Ranjan Muthukrishnan, and Daniel J. Larkin

3 Starry stone-what? Large-growth ( macro ) alga Cousin to native Chara and Nitella species in MN Native to Europe and Asia First found in U.S. in 1970s in New York Paul Skawinski

4 Minnesota First found in lakes currently infested

5 Starry stonewort invasion Can produce dense beds and surface mats Negative effects on native aquatic plants (Brainard and Schulz 2016) Broad tolerance of environmental conditions (Rey-Boissezon and Auderset Joye 2015, Escobar et al. 2016) Competitive advantages over native species (Hutchinson 1975)

6 Reports of previous control efforts being ineffective Copper-based algaecides Mechanical harvest Challenges for treatment

7 Star struck-ture One cell! Aboveground Single cells between nodes No vascular system

8 Star struck-ture Belowground Bulbils White, multicellular, star-shaped Connected via rhizoids Functions: Alga anchor Asexual reproduction

9 Objectives Evaluate the effects of mechanical and algaecide treatments on:

10 Objectives Evaluate the effects of mechanical and algaecide treatments on: 1. Starry stonewort biomass

11 Objectives Evaluate the effects of mechanical and algaecide treatments on: 1. Starry stonewort biomass 2. Bulbil density

12 Objectives Evaluate the effects of mechanical and algaecide treatments on: 1. Starry stonewort biomass 2. Bulbil density 3. Bulbil viability

13 Study lake Lake Koronis, near Paynesville, MN First known occurrence in MN 1,201-ha lake ~100 ha infested in 2015 Stearns, Co. UMN Meeker, Co.

14

15 Treatments Mechanical harvest (10 August 9 September) Liquid algaecide (21 September) Cutrine-Plus; copper ethanolamine complex mixed; granular Granular algaecide (11 October) Cutrine-Plus; copper ethanolamine complex, mixed; granular

16

17 Biomass and bulbil sampling 4 sampling occasions Before all treatments 19 or 26 July (biomass) After mechanical 13 September (biomass) After liquid algaecide 7 October (biomass + bulbils) After granular algaecide 28 October (biomass + bulbils) Collected bulbils for viability testing

18 Biomass

19 Biomass (g/m 2 )

20 Biomass (g/m 2 )

21 Biomass (g/m 2 )

22 Biomass (g/m 2 )

23 Biomass (g/m 2 )

24 Biomass (g/m 2 ) -99%, P < %, P < 0.001

25 Biomass (g/m 2 )

26 Bulbil density

27 Bulbils /m2

28 Bulbils /m2

29 Bulbils /m2

30 Bulbils /m 2 P = 0.005

31 Bulbil viability

32 Bulbil viability Separate tanks from each treatment area Checked every 1-7 days for sprouting 12 weeks (84 days)

33 Bulbils from all areas sprouted within 7 days Bulbil viability

34

35

36 Reference: 84%

37 Reference: 84% Mechanical + algaecide: 70.4%

38 Reference: 84% Mechanical + algaecide: 70.4% Algaecide-only: 86%

39 Conclusions The good: Algaecide treatment and mechanical + algaecide treatment reduced starry stonewort biomass substantially

40 Conclusions The not so good: Algaecide treatment alone did not reduce bulbil viability Bulbil density significantly increased in the area treated with algaecide alone High bulbil viability overall ( 70%)

41 Conclusions Second (granular) algaecide treatment Did not further reduce biomass Did not reduce bulbil density or viability

42 Conclusions High potential of starry stonewort to regenerate and persist via bulbils

43 Why were bulbils unaffected? Physical barrier created by overlying sediment

44 Why were bulbils unaffected? Physical barrier created by overlying sediment

45 Why were bulbils unaffected? Physical barrier created by overlying sediment

46 Why were bulbils unaffected? Physical barrier created by overlying sediment

47 Why did bulbil density increase? Redistribution of resources Internal signaling to increase bulbil production Intercellular transport through plasmodesmata Stimulation of growth as direct response to algaecide Reductions in aboveground biomass created favorable conditions Increased access to nutrients or light Biomass reduction sped up natural seasonal increase in bulbil density

48 Which treatments are wort-while? 1. Initial mechanical harvest to reduce biomass 2. Algaecide treatment of residual biomass

49 Results in context Results from one lake, one year Natural variation and phenology vs. effects of treatment Need to repeat over many lakes and many years

50 Acknowledgements

51 Acknowledgements

52

53

54

55

56

57

58 McComas & Stuckert, 2008

59 Minnesota Department of Natural Resources, 2016

60

61

62

63

64

65

66 McComas & Stuckert, 2008

67

68

69 Implications for management and control Management works. Results may vary. Less snow = more curly-leaf Water quality curly-leaf pondweed

70 Share your management data with MAISRC This research: surveys - 90,000 samples collected - 11 management groups

71 Cooperation was key to this project and greatly appreciated. In memory of Chip Welling who suggested this research and provided significant input and assistance with obtaining data sets. Research and Analysis Contributors: Raymond Newman, Adam Kautza, Thomas Ostendorf, Daniel Larkin Data Contributors: Newman Lab Graduate students: James Johnson, Ajay Jones, Josh Knopik, John JaKa, Melaney Dunne Riley Purgatory Bluff Creek Watershed District Minnesota DNR SLICE program (Donna Dustin) Minnesota DNR Invasive Species Program (Wendy Crowell, Allison Gamble and Keegan Lund) Capitol Region Watershed District (Britta Suppes) Ramsey Washington Watershed District (Simba Blood) Three Rivers Park District (Rich Brasch) Minnehaha Creek Watershed District (Eric Fieldseth) Rice Creek Watershed District (Matt Kocian) Barr Engineering (Meg Rattei) Bluewater Science (Steve McComas) Freshwater Scientific Services (James Johnson) Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative Citizen Commission on Minnesota Resources (LCCMR).

72 Get involved with MAISRC Participate in Starry Trek in 2018: Become an AIS Detector or AIS Tracker: Support MAISRC with a financial gift private gifts in any amount make a critical difference in our efforts!

73 Stay connected Visit and sign up for our newsletter Like MAISRC on Facebook and follow us on Twitter: