Phragmites in Florida: Native or Exotic?

Bill Overholt/1, Megan Hanson/2, Rodrigo Diaz/1 and Dean Williams/2

/1 University of Florida /2 Texas Christian University

Outline

• Why we are interested in Phragmites – Reports of expanding populations in Florida

– An exotic type known to be in USA

• Background

• What we did

• What we found

• What it means

Worldwide Distribution of Phragmites australis

Source: the Global Biodiversity Information Facility, http://www.gbif.org

P. australis may have the widest distribution of any flowering plant (Tucker 1990)

History of Phragmites australis in North America

• Found in ground sloth dung 40,000 years ago

• Artifacts made of Phragmites from 1400 years ago

• Herbarium records from 1800s indicate its presence in the US, but not common

• Early 20th century evidence of expansion in the coastal northeast

Why expansion in the northeast?

• Disturbance of wetlands: 53% of all tidal and non-tidal wetlands were altered or destroyed from 1780 to 1980 (Dahl 1990)

• Increased nutrient load in wetlands especially nitrogen from human activities (Chambers et al. 1999).

Introduction of new genotypes

• First evidence of introduction in 1880 when Phragmites was found growing in Philadelphia where ships’ ballast was off-loaded

• In 2002, Saltonstall conducted genetic studies on 283 leaf tissue samples collected worldwide and 62 N. America herbarium samples collected before 1910

Phragmites australis subsp. americanus

Phragmites australis subsp. berlandieri a.k.a. Gulf Coast – recently Ward (2010) indicated it was a different species, P. karka

Phragmites australis subsp. australis a.k.a. Exotic

Exotic phragmites appears to be more aggressive than native types

• Experimental plantings of Gulf Coast and exotic Phragmites in a Louisiana marsh revealed that the exotic occupied 82% of plots after 14 months, compared to 18% for the Gulf coast type (Howard et al. 2008).

• Comparison of photosynthesis of exotic and native haplotypes in a Maryland tidal marsh showed that the exotic had 51% greater photosynthesis, 100% greater stomatal conductivity and 38-83% greater photosynthetic canopy than the native types. The native performed better than the exotic under low N (Mozdzer and Zieman 2010).

Prior DNA analyses of Florida plants

• 5 early herbaria samples (prior to 1910)

• 7 modern samples (1997-2001), 6 from Brevard Co. and one from around Miami

All 12 samples were identified as the Gulf Coast type

Saltonstall 2002, Ward 2009

Blue Cypress Lake

Little Sawgrass Lake, Brevard Co.

Chocktawhatchee Bay, Walton Co.

Caloosahatchee River, Lee Co.

DNA Analysis – Texas Christian University

Invasive

Gulf Coast

European

518 samples collected from 102 locations • Florida (69) • Alabama (4) • Mississippi (4) • Georgia (2) • South Carolina (5) • Louisiana (16)

Thanks to:

– Kelli Gladding (FWC)

– Matt Phillips (FWC)

– Ryan Hamm (FWC)

– Brent Bachelder (FWC)

– Erica Van Horn (FWC)

– Stephen Hight (USDA/ARS)

40 miles N of FL border on I 95

62 miles west of FL border on Petit Bois Island

Morphological comparison of Gulf Coast and Eurasian Phragmites

Type Stem texture

Stem color

Panicle form

Density

Height (m)

Upper glume (mm)

Lower glume (mm)

Ligule (mm)

Seeds

Gulf Coast

Smooth, shiny

Red where exposed to sunlight

Open 94/m2 a 3.57a

6.04a

3.92a

0.90a

Absent

Eurasian

Ribbed, slightly dull

Green where exposed to sunlight

Compact 167/m2b

2.47b

5.95a

4.38b

0.95a

Absent

Lower glume

Upper glume Ligule

Panicle

Gulf Coast type • Open • Drooping Eurasian type

• Compact • Erect

Ribbing on the stem

Gulf Coast type • Smooth • Shiny

Eurasian type • Finely ribbed • Dull

Color of the stem

Gulf Coast type • When exposed, red • Behind leaf-sheath, green

Eurasian type • When exposed, green • Behind leaf-sheath, green

Mississippi River Delta, South of New Orleans Dauphin Island, Alabama

Eurasian type Gulf Coast type

Gulf Coast type

Eurasian type

According to Dan Ward (UF, Dept. Biology), Gulf Coast Phragmites is morphologically the same as Australian/Polynesian Phragmites, which is considered to be Phragmites karka

Phragmites karka growing near Cairns, Queensland, Australia, 2011

Gulf coast

Distribution of Phragmites karka

www.gbif.org

?

Reed boats?? ‘Reed boats are depicted in early petroglyphs and were common in Ancient Egypt.... They were also constructed from early times in Peru and Bolivia. Reed boats are still used in Peru, Bolivia, Ethiopia, and until recently in Corfu.’ Oldest reed boats dated at 7000 BP

Wikipedia

Peruvian fishing boats

Ra II – sailed by Thor Heyerdahl from Morocco to Barbados in 1970

New Zealand reed boat

Expansion of Phragmites in Apalachicola Bay?

N

N

February 14, 1995 DOQQ

April 3, 2004 DOQQ

January 10, 1999 DOQQ

7,776 m2 10,770 m2

15,910 m2

27,114 m2

January 2, 2012 Google Earth

27,114 m2

2007 2012

20,609 m2 23,622 m2

Ammonium in Apalachicola Bay 2002-2007 Data from: National Estuaries Research Reserve System,

y = -1.2 x 10-5 + 0.487, P=0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

11/5

/200

1

5/24

/200

2

12/1

0/20

02

6/28

/200

3

1/14

/200

4

8/1/

2004

2/17

/200

5

9/5/

2005

3/24

/200

6

10/1

0/20

06

4/28

/200

7

Phosphates

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07 11

/5/2

001

5/24

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2

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/200

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2004

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2005

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/200

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10/1

0/20

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/200

7

y = -9.9 x 10-6 + 0.385, P=0.0002

Nitrates

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8 11

/5/2

001

5/24

/200

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/200

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2005

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6

10/1

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06

y = 8.58 x 10-5 - 2.95, P=0.03

Response to an increase in atmospheric CO2?

Conclusions • Research shows that exotic Eurasian Phragmites may be

more aggressive than the Gulf Coast type

• The exotic type of Phragmites was not found in Florida – this doesn’t mean that it’s not here, but if it is, it has a very restricted distribution

• The closest an exotic population was found to Florida was 40 miles north of the FL/GA border along I95.

• To the west of Florida, and exotic population was found on Petit Bois Island, about 62 miles west of Florida

• Morphological and DNA evidence indicate that Florida Phragmites is Phragmites karka.

• Reasons for expansion of some populations of Phragmites in Florida are not known