Big Cedar Lake Management 2017 AGM Amanda Cooper Bsc. Ecological - - PowerPoint PPT Presentation

Big Cedar Lake Management

2017 AGM

Amanda Cooper

• Bsc. Ecological Restoration

Trent University

History of Management Programs

Weevil Program (EnviroScience Inc. & Trent University)

• Eurasian watermilfoil (EWM) weevil egg stocking

Benthic Mat Program (Trent University)

• Employment of biodegradable benthic mats in EWM patches
• Native plant introduction

EWM Monitoring (EnviroScience Inc. & Trent University)

• Treatment and control sites
• Initial and follow-up site surveys: plant stem density, species

richness and weevil damage

History of Management Programs

Year Lake Association Stocking Private Stocking Annual Total 2011 30,000 23,000 53,000 2012 35,000 27,000 62,000 2013 45,000 22,000 67,000 2014 32,800 1,000 33,800 2015 (Trent University) 2016 (Trent University) 25,000 40,000 25,000 40,000 Total 207,800 73,000 280,800

Breakdown of Milfoil Weevil egg stocking in Big Cedar Lake from 2011-2016

History of Management Programs

Map of all weevil treatment sites (1 & 2), weevil + mat treatment sites (3, 4, & 5), and control sites (C) on Big Cedar Lake during 2016.

EWM Management Progress

Big Cedar Lake Management Objectives:

• Active management of ecological health of the lake and its

surroundings (monitoring, protecting and restoring)

• Preservation and improvement (or regeneration) of the

environmental health of BCL

• Provide information concerning matters related to the BCL

community

Trent’s Management Objectives:

• Examine the effect of EWM weevil augmentation treatments on

EWM density and species richness

• Observe trends in EWM density throughout the duration of the 6-

year augmentation program

2016 Results – Weevil Damage

• Weevil damage increases within season but does not significantly

change between years

• Inter-annual changes are likely dependent on the state of EWM in

each new year

• High densities of weevils will not necessarily be maintained year-

to-year in a patch

2016 Results – Weevil Damage

Mean weevil damage in treatment and control plots during June and August 2015 Mean weevil damage in treatment and control plots during August 2015 and 2016

2016 Results – EWM Stem Density

• No significant changes in EWM stem density within a season,

however dramatic changes from one year to another

• Collapses of EWM in treatment sites tend to occur during the

winter rather than the summer

• It is likely that damage inhibits the ability of EWM to overwinter
• Since 2011, EWM density has declined considerably, however this

appears to have plateaued which suggests a lake-scale saturation

• f weevils

2016 Results – EWM Stem Density

Historical changes in the average stem densities of M. spicatum patches in Big Cedar Lake from 2011-2016. The sites are identified by EnviroScience site codes; EnviroScience sites that overlap with the 2015 study have their new name in brackets.

100 200 300 400 500 600 700 800 01-Jan-11 02-Jul-11 01-Jan-12 01-Jul-12 31-Dec-12 02-Jul-13 31-Dec-13 02-Jul-14 31-Dec-14 02-Jul-15 01-Jan-16 01-Jul-16 31-Dec-16 S1 (W2) S2 S3 (W1) S4 S5 old S5 (W4) S6 (C4) M2 Average

2016 Results – EWM Stem Density

Mean EWM stem density in treatment and control plots during June and August 2015 Mean EWM stem density in treatment and control plots during August 2015 and 2016

2016 Results – Species Richness

• Despite EWM density declining in treatment sites, rapid response

in native plant growth has not been apparent

• Pattern of diminishing returns is likely a result of both the

creation of small EWM fragments as well as the theory of natural equilibrium in biocontrol relationships

Future of BCL Management

• Expand the use of vegetated benthic mats
• Stocking of weevils in specific areas
• Working with shoreline residents in developing a DIY

program for managing EWM at their own shoreline (weed pulling and DIY installation of vegetated benthic mats)

• Development of an on-going lake assessment program to

monitor the lake over time

Healthy Lake Program

• Initial EWM problem, however need to be mindful of and

prepared for possible future threats

• Necessary focus on long-term health of BCL through a broader,

more comprehensive and integrated approach Main Goal: monitor and identify the appropriate approach to managing the variety of issues facing BCL now and into the future, in a sustainable and cost-effective manner Ideal Solution: acquire natural balance within the lake, as an entire ecosystem, to restore beneficial recreational areas (swimming and boating) while enhancing spawning areas (fish populations)

Healthy Lake Program

Potential Future Challenge – Water Solider (Stratiotes aloides)?

• Trent River and Black River
• Dense mats that crowds native

vegetation

• Sharp serrated leaf edges
• Prevent colonization through

avoiding it as an

• rnamental/aquarium plant,

inspect boat/trailer/equipment after each use

Questions