Starry Stonewort (): Research Efforts Towards an Integrated Management Plan

Anna K. Monfils, Heather Dame, Lindsay Chadderton, Andrew Tucker, Pam Tyning, Paul Hausler, Ryan Thum, and James McNair MISGP Project Objectives

• Employ experimental field trials to: – Optimize herbicide control – Test the efficacy of biodegradable benthic SSW– Gun Lake, Barry Co., MI barriers • Three species: – Eurasian watermilfoil (EWM) – Starry stonewort (SSW) – Carolina fanwort (CFW) Heather Dame, Gun Lake, Barry Co., MI Nitellopsis obtusa – Starry Stonewort (SSW) • Monitor phenology and biology of SSW and document basic life history • Apply and assess efficacy of herbicide treatment • Deploy and assess efficacy of biodegradable benthic barriers

SSW– Gun Lake, Barry Co., MI Nitellopsis obtusa – Starry Stonewort (SSW) • Monitor phenology and biology of SSW and document basic life history • Apply and assess efficacy of herbicide treatment • Deploy and assess efficacy of biodegradable benthic barriers

SSW– Gun Lake, Barry Co., MI What do we know about Starry Stonewort? • Macrophytic green algae, member of order – Other Michigan genera include , , Tolypella • Branches long single celled internodes • Whorls of uneven branchlets extend from nodes • Multicellular rhizoids anchor to sediment

SSW– Gun Lake, Barry Co., MI SSW: How does it reproduce?

• Asexual reproduction - Bulbils – Noted throughout growing season in MI – Star-shaped – Primarily develop below soil – Germinate in 3-5 days • Asexual reproduction - Fragmentation – Common in • Sexual Reproduction (North America) – Antheridia documented SSW Bulbils, Photo from Progressive AE SSW: What is the native range?

• Native to Europe and Asia – threatened or endangered in much of its native habitat

(from Soulié-Märsche 2002) SSW: What is the invasive range?

• North America - 1978 in the St. Lawrence Seaway (Geis et al. 1981) • St. Claire and Detroit Rivers in 1986 (Schloesser 1986) • Michigan Inland lakes in 2006 (Pullman 2010) – Present in over half of the counties in Michigan’s Lower Peninsula and is spreading to other Midwestern states. – MN, IN, WI, NY

MISIN April 2016 SSW: What do we know about the life cycle (native range)?

• Annual growth cycle (Hutchinson 1975, Hargeby 1990) – Emerges in April – May – Reaches peak biomass in June – Dies back in fall • Can persist through mild winters (UK Biodiversity Action Plan) SSW: What do we know about the life cycle (invasive range)? • St. Lawrence River (Geis et al. 1981) – Emerges in July • Detroit – St. Clair River system (Hudson et al. 1986) – Emerges in July – Reaches peak biomass in Sept. • Detroit River (Nichols et al. 1988) – Emerges in August – Peak biomass in Sept. – Gradually declines Dec. – Jan. – Rapidly declines in Feb. – Absent by March SSW: What do we know about the life cycle (invasive range)?

26 Jan 2014, Photo courtesy of Scott Brown SSW: What do we know about the life cycle (invasive range)?

• 2015 – 2016 Gun Lake, Allegan Co., MI – New growth late March to early April – Accelerated growth in July – Senesces early September – Die back by early March

New growth (~8 cm) of SSW from bulbils in sediment, Gun Lake, Barry Co., MI (Aug) SSW: What is the Growth Pattern?

• Can form monocultures or persist in mixed Kevin Nevorski, monoculture of SSW, Gun Lake, Barry Co., MI communities • Found in depths up to 10-12 m • Can form dense mats up to 2m tall

Dense mat of SSW with Chara, Gun Lake, Barry Co., MI SSW: What do we know about rate of spread? Houghton Lake Starry Stonewort Point-Intercept Survey Results (August 2013 & 2015) 200

180

160

140 Sites

120 of 100 2013 80 2015 60 Number 40

20

0 Rare Sparse Common Dense Total

Data retrieved from Houghton Lake 2015 Report, prepared by Progressive AE. SSW: What do we know about habitat? • Intolerant of eutrophication and prefers calcium rich water (Brown 2014) – Projected to occur in 75% of Michigan inland lakes • Can survive in slightly brackish water (Winter et al.1999, Naz et al. 2010) – Possible introduction to North America via ballast water (Sleith st al. 2015)

Bulbil on SSW rhizoid, Gun Lake, Barry Co., MI SSW: What do we know about habitat? • EWM present in 88% of Michigan lakes reported to have SSW in 2012 (Brown 2014) • In New York, all lakes with SSW had substantial human development and boat launches (Sleith et al. 2015)

Gun Lake, Barry Co., MI What do we need to know about SSW? • Life history, phenology and biology • What is the viability of SSW bulbils? • Can SSW reproduce via fragments? • What is the environmental impact? • What is the best mechanism for detection? • How do we prevent spread? • What are effective management practices? Nitellopsis obtusa – Starry Stonewort (SSW) • Monitor phenology and biology of SSW and document basic life history • Apply and assess efficacy of herbicide treatment • Deploy and assess efficacy of biodegradable benthic barriers

SSW– Gun Lake, Barry Co., MI SSW Pilot Study: Study Sites • Gun Lake, Barry Co., MI – Surveyed community to define vegetation zone – Size to accommodate 50 m buffer – Two treatment and two control sites (10m x 10m) SSW Pilot Study: Treatments

• 2 acres with Komeen crystals/chelated copper (30 lb/acre) – Representative of invasive SSW mat – 75 - 92% SSW – Chara spp, pondweed, eel grass SSW Pilot Study: Treatments

• 1 acre with copper sulfate (4.4 lb/acre-ft) and endothall (0.75 gal/acre) – Mixed community – 24-30% SSW – Chara spp (dominate), pondweed, eel grass, naiad SSW Pilot Study: Data • Gun Lake, Barry Co., MI – Pre-treatment abiotic surveys - Water depth - Surface and bottom temperature, pH, DO (%), conductivity - Water chemistry – Pre/post-treatment biotic surveys • Systematic random design • 25 sample points per treatment and control • Biomass sampling (0.04 m2 quadrat; pre- and 2 weeks post- treatment) – Dry weight biomass by species • Height of SSW (weekly for six weeks) SSW: Chelated Copper post-treatment bed height

Height at 1, 8, 15, 24, 34, and 47 days post-treatment SSW: Chelated Copper pre- and post-treatment Biomass SSW: Copper with Endothall post-treatment bed height

Height at 1, 8, 15, 24, 34, and 47 days post-treatment SSW: Copper with Endothall pre- and post-treatment Biomass 2016 SSW Herbicide Study

• Gun Lake, Barry Co., MI – 3 replicates; 3 controls (10m x 10m) – Highly impacted canals – June and July treatments of Komeen Krystal (15.5 lb/acft of plant height) with Endothall (2.2 pints/acre foot) – August mechanical harvesting 2016 SSW Herbicide Study • Gun Lake, Barry Co., MI (8 visits total) – Pre-treatment abiotic surveys (before each treatment) - Water depth - Surface and bottom temperature, pH, DO (%), conductivity - Water chemistry - Air, surface, bottom light intensity - Distance from surface of water to plant canopy – Pre/post-treatment biotic surveys (for each treatment) • Systematic random design • 5 sample points per treatment and control • Biomass sampling (vertical rake) – Wet biomass by species • Species present • Percent cover (m2 quadrats) Nitellopsis obtusa – Starry Stonewort (SSW) • Monitor phenology and biology of SSW and document basic life history • Apply and assess efficacy of herbicide treatment • Deploy and assess efficacy of biodegradable benthic barriers

SSW– Gun Lake, Barry Co., MI SSW Pilot Study: Benthic Mats • Gun Lake, Barry Co., MI – Surveyed plant community to define vegetation zone – Three treatments (14 oz. single, double and triple layers) – Two control sites (10m x 10m) SSW Pilot Study: Benthic Mat Treatments • Treatment: Single Layer of 14 oz. matting > 80% SSW • Treatment: Three layers of 14 oz. matting • Control • Highly Impacted – >80% SSW SSW Pilot Study: Benthic Mat Treatments • Treatment: Two

Layers of 14 oz. ~ 10% SSW matting • Control • Mixed community – 10% SSW SSW Pilot Study: Benthic Mats 2016 monitoring of 2015 deployed benthic mats – Percent visible edge – Condition of matting – Level of sedimentation – Species present – Percent cover – Status of target

2015 Benthic Mats, Gun Lake, Allegan Co., MI April 2016: Benthic Mats 1-layer mat 3-layer mat Control

10% cover 6% cover 100% cover • 100% SSW • 95% Chara • 80% SSW • 5% SSW • 20% Chara

Appeared to have more per Thick layer of algae on mat with a SSW bulbils found throughout plot. quadrat than 3-layer mat. layer of sediment on top. April 2016: Benthic Mats 2-layer mat Control

40% macrophyte cover 86% macrophyte cover • 100% Chara • 90% Chara • 5% SSW • 5% Eurasian watermilfoil Eurasian watermilfoil fragment growing on top of mat.

Chara (<5 cm tall) growing through mat. 2016 Benthic Mat Deployment

Caffrey et al. 2010 Aquatic Invasions 5: 123-129 2016 Benthic Mat Treatments

• Long Lake, Ionia Co., MI – 3 replicates; 3 controls (12m x 12m) – Highly impacted region – Deploy benthic mats (18 oz.) May 26 & 27 2016 SSW Herbicide Study • Long Lake, Ionia Co., MI (5 observation; 2 biomass) – Systematic random design – 5 sample points per treatment and control • Observation – Status of target – Percent visible edge – SCUBA Quadrat (1 m2) - Condition of matting - Level of sedimentation - Species present - Percent cover • Biomass/Observation - SCUBA Quadrat (0.1m2) - Wet biomass by species - Species present - Distance from surface of water to plant canopy - Water depth - Surface and bottom temperature, pH, DO (%), conductivity - Water chemistry - Air, surface, bottom light intensity Ongoing goals

• Continued monitoring of phenology and biology of SSW – Strategic long-term monitoring • Major revision of MI SSW Species Strategy – EPA Great Lakes Research Initiative 205(j) grant • Integrate resources and collaborate across Great Lakes region MISGP Objectives

• Develop and disseminate an integrated, adaptive weed management plan that will: – Detail a better understanding of the mechanisms behind successful herbicide treatments – Provide additional treatment options – Improve best management practices Acknowledgements

• Heather Dame, Blake Cahill, Kevin Nevorski, Clint Pogue and Rachel Hackett (CMU – Team Plant) • Michigan Invasive Species Grant Program (MDNR) • Sarah LeSage (MDEQ) • Syndell Parks (GVSU) • Sue Tangora (MDNR) • Kyle Kucher (MDNR)