Chris Zimmerman and Becky ShirerThe Nature Conservancy, New York

Trajectory of Native Plant Recovery:Management of Five Phragmites australis Stands

in a Hudson River Freshwater Tidal Wetland

Before After

1

Introduction

Phragmites australis alters vegetation composition and structure.

~ $4. 6 million spent on management between 2005 and 2009 (Martin and Blossey 2013).

Call for Monitoring of biological management outcomes.

Limited information on effectiveness of eliminating small stands and vegetation response.

2

RA

3

Ramshorn Marsh Hudson River 1,000 ha of freshwater

tidal marsh

~ 35% PhragmitesRamshorn Marsh 47 ha emergent marsh 3% Phragmites (1.5 ha)

3

Management Goals and Research Questions

Goals Eliminate 5 Phragmites stands to maintain 47 ha

of freshwater tidal marsh Restore native plant community within treatment standsQuestions Can small Phragmites stands (

Sample Methods and Design

5 treatment stands and control. 10 randomly located 1m2 plots in

interior and exterior of the stand.

Count live and dead Phragmitesstems in interior plots.

Estimate cover of all species and litter in all plots.

Total stem census in 3rd year

10

Patch 1 m2

5

Herbicide Treatment

Contracted with licensed aquatic applicator. 1st Treatment (2010): Broadcast application of

aquatic labeled glyphosate-based herbicide at labeled rate using a Marsh Master.

Follow up treatment: (2011 & 2012) Backpack sprayer at 1% solution.

6

Phragmites Treatment Efficacy

77

Phragmites Treatment Efficacy

3 Years Post-Initial Treatment (2013)

Stand Ha % Reduction Total Stems

1 0.76 98.6 4,309

2 0.30 98.2 1,897

3 0.30 95.4 3,497

4 0.04 99.9 3

5 0.04 96.0 139

8

Phragmites Treatment Efficacy

Stand1 Phragmites

Stem Density

9

Native Plant Recovery

1010

Photo Monitoring Stand 1 Pretreatment 2011

2012 2013

11

Similar Composition? Reference and Treatment

Stand Size(ha) A P

1 0.76 0.050 0.007

2 0.30 0.065 0.015

3 0.30 0.058 0.018

4 0.04 0.123 0.001

5 0.04 - 0.034 0.970

Multiple Response Permutation Procedure

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Similar Composition? Reference and Treatment

Pre-treatment 3 Years Post-Initial Treatment

Non-metric Multidimensional Scaling (NMS) ordination of species composition

LEEORY

POLARI

13

Similar Composition? Reference and Treatment

Exterior (Reference) % Interior (Treatment) %Impatiens capensis 37.1 Leersia oryzoides 15.0Typha angustifolia 14.3 Sagittaria latifolia 11.5Peltandra virginica 10.7 Peltandra virginica 11.0Apios americana 10.0 Bidens cernua 10.0Convolvulus sepium 7.1 Impatiens capensis 9.0

Exterior (Reference) % Interior (Treatment) %Typha angustifolia 35.0 Typha angustifolia 40.5Peltandra virginica 24.0 Peltandra virginica 20.5Impatiens capensis 5.0 Impatiens capensis 3.0Iris pseudacorus 1.0 Sagittaria latifolia 1.5Acorus calamus 0.5 Iris pseudacorus 1.0

Stand 1 (0.80 ha)

Stand 5 (0.04 ha)

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Conclusions Treatment Efficacy

Can small stands be eliminated? Stands < 0.10 ha may be feasible EDRR opportunities limited Larger stands will require management

over the long-term

Limiting factors Search effort and probability of stem

detection Rhizome viability and seed bank Herbicide effectiveness on small stems

15

Conclusions Native Plant Recovery

Three stands dominate by disturbance dependent species

Factors influencing recovery: Pre-treatment native species abundance Hydrologic inundation Thatch layer

To maintain native plant diversity will require managing for low Phragmites stem density (

Additional Resources

Zimmerman, C. and R. Shirer. 2013. Trajectory of vegetation recovery in five Phragmites australis stands in response to management in a Hudson River freshwater tidal wetland. The Nature Conservancy in eastern New York, Albany, NY

Invasive Plant Management Decision Analysis Tool http://ipmdat.org/

A Guide for Strategic management of Phragmites Australis in tidal Hudson River Wetlands

17

Acknowledgements

Audubon Scenic Hudson Stuart Findlay

Larry Federman Steve Young Laura Lukas Troy Weldy Jason BriedSuneeti Jog

Jeremy Roberts Arianne Messerman

Dan Sorenson

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Trajectory of Native Plant Recovery:Management of Five Phragmites australis Stands in a Hudson River Freshwater Tidal Wetland IntroductionSlide Number 3Management Goals and Research QuestionsSample Methods and DesignHerbicide TreatmentPhragmites Treatment EfficacyPhragmites Treatment EfficacyPhragmites Treatment EfficacyNative Plant Recovery Photo Monitoring Stand 1 Similar Composition? Reference and TreatmentSimilar Composition? Reference and TreatmentSimilar Composition? Reference and TreatmentConclusions Treatment Efficacy Conclusions Native Plant Recovery Additional ResourcesAcknowledgements