SOIL SALINITY AND THE OCCURRENCE OF INVASIVE PHRAGMITES AUSTRALIS IN SCARBOROUGH MARSH

Anthony J. DeVecchis and Dr. Joseph K. Staples

Abstract

Background Importance of tidal marshes like Scarborough Marsh Phragmites australis as an invasive species Previous research

Methods and Results Analysis of soil salinity, temperature, and moisture Plant community characteristics Connection between soil salinity and P. australis

Significance Insight and management – locally and beyond

Functions of tidal marsh ecosystems Productivity Coastal Buffer Key Habitat

Significance of Scarborough Marsh Maine Natural Areas Program

Background

Invasive Phragmites australis

Spread in New England (Fussell et al., 2015)

Tolerance (Vasquez et al., 2005)

Changes to salinities in salt marshes (Fussell et al., 2015; Warren et al, 2001)

Methods and Materials

Analysis of Soil Moisture, Salinity, and Temperature

Paired Transects to upland edge (Morgan and Adams, 2018; Warren et al, 2001)

Upper tidal reaches Conductivity as proxy for

salinity (Yang et al. 2019) Relationship of

conductivity to plant species

Analysis and Results

Conversion of conductivity to specific conductance Simple t-tests comparing Spartina and Phragmites

data Significant differences in soil specific conductance

were observed along each transect

Specific conductance

0

200

400

600

800

1000

1200

1400Sp

artin

a

Phra

gmite

s

Spar

tina

Phra

gmite

s

Libby River 1 Libby River 2

Spec

ific

Con

duct

ance

(µs/

cm)

t-test P < 0.001

0

200

400

600

800

1000

1200

1400

Spar

tina

Phra

gmite

s

Spar

tina

Phra

gmite

s

Nonesuch River 1 Nonesuch River 2

Spec

ific

Con

duct

ance

(µs/

cm)

t-test P < 0.05a

b

a

b

t-test P < 0.02

Significance

Results yielding similar results to previous research (Fussell et al., 2015; Warren et al., 2001)

Indication of freshwater input

Fairly rapid, easily repeatable method

Information for conservation efforts

Complications

Slow progress sampling in winter

Impact of ice on conductivity

Native vs. Invasive Influences of road

salting Inability to access the

Dunstan River Details

Conclusions

Reliability of data Future Research

Acknowledgements

Environmental Science and Policy Faculty at USM Dr. Joseph Staples and Dr. Karen Wilson

Friends of Scarborough Marsh Steve Pinette

Maine Department of Inland Fisheries and Wildlife Brad Zitske

Field Data Collection Help Sam Whitted

References Fussell, S. B., Dionne, M. L., & Theodose, T. A. (2015). Expansion rates of Phragmites australis

patches in a partially restored Maine salt marsh. Wetlands, 35(3), 557-565. https://doi.org/10.1007/s13157-015-0645-3

Maine Natural Areas Program. (2013). Focus Areas of Ecological Significance: Scarborough Marsh. https://www.maine.gov/dacf/mnap/focusarea/scarborough_marsh_focus_area.pdf

Morgan, P. A., & Adams, M. D. O. (2018). Tidal marshes in the Saco river estuary, Maine: A study of plant diversity and possible effects of shoreline development. Rhodora, 119(980), 304-331. https://doi.org/10.3119/16-19

Vasquez, E. A., Glenn, E. P., Brown, J. J., Guntenspergen, G. R., & Nelson, S. G. (2005). Salt tolerance underlies the cryptic invasion of North American salt marshes by an introduced haplotype of the common reed Phragmites australis (poaceae). Marine Ecology. Progress Series (Halstenbek), 298, 1-8. https://doi.org/10.3354/meps298001

Warren, R. S., Fell, P. E., Grimsby, J. L., Buck, E. L., Rilling, G. C., & Fertik, R. A. (2001). Rates, patterns, and impacts of Phragmites australis expansion and effects of experimental Phragmites control on vegetation, macroinvertebrates, and fish within tidelands of the lower Connecticut River. Estuaries, 24(1), 90-107. https://doi.org/10.2307/1352816

Yang, S., Liu, F., Song, X., Lu, Y., Li, D., Zhao, Y., & Zhang, G. (2019). Mapping topsoil electrical conductivity by a mixed geographically weighted regression kriging: A case study in the heiheriver basin, northwest china. Ecological Indicators, 102, 252-264. https://doi.org/10.1016/j.ecolind.2019.02.038