Invasion success of Invasion success of alien aquaticalien aquaticplants in their native and plants in their native and

introduced ranges. introduced ranges. ComparisonComparison between their between their

invasiveness ininvasiveness in North America and North America and in Francein France..

ThiThiéébautbaut GabrielleGabrielle

Université de Metz, UFR Sci FA, Laboratoire Biodiversité & Fonctionnement des Ecosystèmes, Avenue du Général Delestraint, 57070 METZ.

Email : thiebaut@sciences.univ-metz.fr

Acknowledgments:JN Beisel, P. Rocco and Karotsch Kevin for their helpful assistance .

Aquatic plants comprise few species worldwide,yet introductions of macrophytes represent some of the most examples ofdramatic biological invasions.

The different steps (The different steps (HegerHeger, 2001):, 2001):1.1. Immigration: Immigration: presence in the new area

2.2. Spontaneous establishmentSpontaneous establishment:: independent growth and reproduction of at least one individual

3.3. PPermanentermanent establishmentestablishment: : Population growth to Minimum Viable Population

4.4. Colonisation of new localities:Colonisation of new localities:

→ The height of each step depends on the ability of the species to overcome environmental limitations.

Generally, most Generally, most plant plant species have expanded species have expanded after a lag phaseafter a lag phase ..

L. L. hexapetalahexapetala

Ludwigia hexapetala. • Introduced in 1836 in Montpellier (France),•widespread invasive since 30 years.

The basic The basic rule rule (Williamson,1993) (Williamson,1993)

• 10% of imported plants escape to become introduced

• 10% of introduced invaders, become established,

• 10% of those established become pests.

Our objectives are to compare the distribution, the biologydistribution, the biology and the ecologyecologyof 27 spreading aquatic plants in their introduced rangesintroduced ranges and in their native native ranges.

We made the following two reciprocal comparisons:

• first European aquatic plants in France and in North America,

• and North American plants in France and in North America.

Material and MethodsMaterial and Methods

NonindigenousNonindigenous plants in North Americaplants in North America

The invasion of alien species has occurred since the mid-eighteenth century by the migration and settlement of European people on the North American continent.The documentation of introduction of each species was almost entirely based on information in the literature (e.g. Atlas North America).

IInvasinvasiveve AquaticAquatic Plants in FrancePlants in France11 invasive macrophytes in France (Muller et al.,

2004): •• 33 amphiphytesamphiphytes: Ludwigia peploides, L.

hexapetala, Myriophyllum aquaticum•• 88 hydrophyteshydrophytes plantsplants: A. caroliniana, A.

filiculoides, E. nuttallii, E. canadensis, L.minuta, L. turionifera.E. densa, L. major.9 widespread & invasive species (+100 sites /county) et 2 potentially invasives (between 11 et 100 sites/county).

Tab 1:Tab 1: Date of introduction Date of introduction in France and in in France and in NorthNorth AmericaAmerica

* native from South AmericaQ: questionable origin: considered by some to be native, but probably nonindigenous and wellnaturalized in the USN = nativeE= nonindigenous

N.America First found in USA First found in Canada France First found in FranceAzolla caroliniana N E no dataAzolla filiculoides N E 1880 ( Deux-Sèvres)Elodea nuttallii N E 1959 ( Alsace)

Group I Elodea canadensis N E 1845Lemna minuta N E 1965 (Pyrénées-Atlantiques)Lemna turionifera N E 1992 ( Alsace, Lorraine)Acorus calamus Q 1600 NButomus umbellatus E 1905 (St, Lawrence R, QUE) NCallitriche stagnalis E 1861 (New York) NGlyceria maxima E 1975 ( Wisconsin), 1956 (Ontario) NHydrocharis morus-ranae E 1932 (Ontario) NIris pseudacorus E <1980 (Washington, DC); 1961 (colombie britannique) NMarsilea quadrifolia E 1860 (Bantam Lake, CT) NMyriophyllum spicatum E 1942 (Washington, DC) 1960 (Ontario) N

Group II Myosotis scorpioides E NNasturtium officinalle E < 1826 NNajas minor E 1934 ( Hudson river) NNymphoides peltata E 1882 (Winchester, MA) ? ( Rideau river) NPhalaris arundinacea Q 1800 NPotamogeton crispus E 1859 (Wilmington, DE) <1956 (Ontario) NRorripa amphibia E 1831 NTrapa natans E <1879 (Middlessex Co,MA) NVeronica beccabunga E 1876 (Hudson Co, NJ) NEgeria densa* E 1893 (Long Island, NY); E 1961 (Manche)

Group III Ludwigia peploides* E E 1820-1830 (Montpellier)Ludwigia hexapetala* E E 1820-1830 (Montpellier)Myriophyllum aquaticum* E 1890 (Haddonfield, NJ) E 1880 ( Bordeaux)

The selected plantsThe selected plants

• 6 species coming from N. America and invasive in France (group I);

• 17 species coming from Europe and invasive in N. America (group II);

• 4 species coming from S. America and invasive in France and in N. America.

Lemna Lemna minutaminuta

P. crispus

G. maxima

Family Growth habitAzolla caroliniana Azollaceae Free-floatingAzolla filiculoides Azollaceae Free-floatingElodea nuttallii Hydrocharitaceae submersed

Group I Elodea canadensis Hydrocharitaceae submersedLemna minuta Lemnacaeae Free-floatingLemna turionifera Lemnacaeae Free-floatingAcorus calamus Aracae emergentButomus umbellatus Butomaceae emergentCallitriche stagnalis Callitichaceae submersedGlyceria maxima Poaceae emergentHydrocharis morus-ranae Hydrocharitaceae Free-floatingIris pseudacorus Iridaceae emergentMarsilea quadrifolia Marsilaceae emergentMyriophyllum spicatum Haloragaceae submersed

Group II Myosotis scorpioides Boraginaceae emergentNasturtium officinalle Brassicaceae emergentNajas minor Najadaceae submersedNymphoides peltata Menyanthaceae submersedPhalaris arundinacea Poaceae emergentPotamogeton crispus Potamogetonaceae submersedRorripa amphibia Brassicaceae emergentTrapa natans Trapaceae Free-floatingVeronica beccabunga Scrophulariaceae emergentEgeria densa* Hydrocharitaceae submersed

Group III Ludwigia peploides* Onagraceae submersedLudwigia hexapetala* Onagraceae submersedMyriophyllum aquaticum* Haloragaceae submersed

Tab.2: Main invasive plants in France and in N. America

SpeciesSpecies traitstraits

12 biological traits were selected.The documentation of species traits was

based on literature data.

Among them: • Size• Leaf size: length, width• Flower width• Reproduction: winter buds, seeds, rhizome,

stolons….• Dissemination: water, animals, wind, human

activities• Growth form: free, anchored and submersed,

anchored and support tissue, floating leaves• Biological type: aquatic, helophyte, amphiphyte.

EcologicalEcological traitstraits

• Water pH• Water velocity• Water trophic requirements• Light requirements.

The available information on species traits was structured using MCA on fuzzy table with a scale of 0 (no affinity of a species) to 1 (affinity of a species).

ResultsResults

Non native aquatic plants have been classified in three groups:

• i) restricted restricted and invasive plants, • ii) potentiallypotentially invasive and ,• iii) widespreadwidespread and invasive macrophytes.

Tab.3.NTab.3.Nonindigenousonindigenous plants classification according to plants classification according to their invasiveness intheir invasiveness in N.N.America and in America and in FranceFrance

Invasive potentially widespread restricted invasive & invasive

Azolla caroliniana xAzolla filiculoides xElodea nuttallii x

Group I Elodea canadensis xLemna minuta xLemna turionifera xAcorus calamus x (NE, Central USA))Butomus umbellatus x (Connecticut) x (Eastern region USA, Canada)Callitriche stagnalis x (Canada, USA) x (Connecticut)Glyceria maxima x (Eastern region USA) x(Canada)Hydrocharis morus-ranae x (Eastern region USA)Iris pseudacorus xMarsilea quadrifolia x (Eastern region USA) x (Connecticut)Myriophyllum spicatum x

Group II Myosotis scorpioides x (Connecticut) x (Canada)Nasturtium officinalle x (Eastern region USA) xNajas minor x (Eastern region USA)Nymphoides peltata x x (Eastern region USA)Phalaris arundinacea xPotamogeton crispus xRorripa amphibia x (Eastern region USA) x (Canada)Typha angustifolia xTrapa natans x x (Eastern region USA)Veronica beccabunga xEgeria densa* x (Connecticut)) x (Eastern region USA, France)

Group III Ludwigia peploides* x (France)Ludwigia hexapetala* x (France)Myriophyllum aquaticum* x (Eastern region USA) x (Connecticut) x (France)

MostMost nonindigenous aquatic species are widespread or potentially invasivewidespread or potentially invasive in their introduced country, and only few alien species are known from a few occurrences.

SomeSome species are viewed as restrictedrestricted in some areas (e.g. G. maxima in USA) and are considered as widespread elsewhere (in Canada).

E. nuttalliiE. nuttallii in France (in France (alienalien speciesspecies))

Invasive Invasive andand widespreadwidespread in in NorthNorthof France,of France,GermanyGermany,,EnglandEngland, , BelgiumBelgium..

Rare in Rare in SouthSouth ofof France.France.

Elodea nuttalliiElodea nuttallii in in N.AmericaN.America (native)(native)

No instance in N. America where E.nuttallii or E. canadensis is weedy.

E. nuttallii

Pond Troy (NYS)

TrapaTrapa natansnatans in in N.AmericaN.America (non (non indigenousindigenous area)area)

- Widespread & invasive in Eastern region of USA

- endangered in much of Europe(native)

T. natans in Cohoes Lake (NYS)

WidespreadWidespread speciesspecies iin Francen France andand in N. in N. AmericaAmerica

Myriophyllum Myriophyllum spicatumspicatum

Native from South AmericaNative from Europe

Relationships among speciesRelationships among species traitstraits

Traits modalities are mainly distributed along Traits modalities are mainly distributed along the F1 and F2 axes (17, 0 and 11.6% of the F1 and F2 axes (17, 0 and 11.6% of total inertia)total inertia)– F1 is mainly related to potential size, leaf size

(length, width), biological type, growth form and reproduction

– F2 is related to leaf length, biological type and to a minor extend with light requirements.

<=20cm20-50cm

50-70cm

70-150cm

150-250cm

>250cmSize

<=1cm

1-3cm3-5cm

5-20cm

20-80cm

>80cm

Leaf length

<=2mm

2-4mm

4-12mm

12-20mm

20-40mm>40mmLeaf width

<=3mm

3-10mm>10mm

Flower widthfragmentation

rhizomes

stolons

winterbudsseeds

other

Reproduction

hydrochory

zoochory

anemochory

human dissemination

Dissemination

helophyte

hydrophyte

amphyphyte

Biological Type

freeanchored

floating leaves

support tissue

submersed

Growth form

stilllow velocity

running

Water velocity

oligotrophe

mesotropheeutrophe

Trophic level

acid

neutral

alkaline

pH

shade

shade 50%

unshaded

Light

-1.9

1.3-1.3 1.4

0.750.51

0.66

0.62

0.70

0.66

0.57

In bold: correlation ratios for each trait species indicated on the axes

Distribution of Distribution of modalitiesmodalities on on the F1xF2 the F1xF2 planesplanes

0.22 0.34

0.15

0.15

0.05 0.03

0.02

0.050.37

0.40 0.12

0.050.050.05

0.040.03

0.11

F1: biologyaxis

F2: distribution axis

Main axes are not related to ecological traits but related to morphology.

→ Uniformity of the aquatic environment Uniformity of the aquatic environment allows allows macrophytemacrophyte to occupy very large to occupy very large ranges.ranges.

1 2

-1.4

0.69-0.96 0.79

Traits Traits comparisoncomparison betweenbetween N.AmericaN.America andand FranceFrance

No difference between traits of species in France and in North America.

1: 1: NorthNorth AmericaAmerica, , 2: France2: France

Traits Traits comparisoncomparison betweenbetween France France andand N. N. AmericaAmerica

The coThe co--structure between species traits in structure between species traits in France and in North America varies France and in North America varies according according to theto the species.species.

•• HelophytesHelophytes (I. pseudacorus, V. beccabunga…) have different species traits in NA and France;

•• FreeFree--floatingfloating species have relatively short vectors;•• Aquatic species or Aquatic species or amphiphytesamphiphytes widespread in the 2

areas (e.g.M. spicatum) have a high co-structure between traits in France and in N. America.

Traits Traits comparisoncomparison betweenbetween France France andand N. N. AmericaAmerica

Acal

Acar

Afil

Bumb

Csta

Eden

EnutEcan

Gmax

Hmor

Ipseu

LminoLminu

Ltur

Lgra

Lpep

Mqua

Msco

Maqu

Mspi

Nmar Nmin

Noff

Npel

Paru

Pcri

Ramp

Tnat

Vbec

-1.1

0.86-0.84 1.1

3 groups :1.Helophyte2.Amphiphyte2.Amphiphyte3.Aquatic plants3.Aquatic plants.

33

1

2

MM. . aquaticumaquaticum

F1: 17%

F2: 12%

ConclusionsConclusions

•• Invasive aquatic plants when introduced Invasive aquatic plants when introduced into into nonindigenousnonindigenous habitats were habitats were characterizedcharacterized by:by:–– a high plasticity– a broad distribution..

•• The architecture of invasive plants in non The architecture of invasive plants in non indigenous and in native area:indigenous and in native area:– Morphology of emergent species differed in

France and in North America.– Submersed and floating plants are very

plastic in the two areas. No difference.

The majority of invasive species share some or The majority of invasive species share some or all the following characteristicsall the following characteristics:

•short life cycle,

•rapid growth rate,

•high level of energy allocated to reproduction,

•efficient dispersal mechanisms,

•high population growth rate,

• and flexible use of environmental resources.

Ludwigia uruguyensis in Britain (France)

Propagules

Knowledge of strategies of reproduction, dispersion and competition among aquatic plants in their native area remains fragmentary .

Physiological traits are unknown

In addition, dIn addition, declineecline of widespread species of widespread species (e.g. (e.g. MM. . spicatumspicatum in USA and in USA and E. E. canadensiscanadensis in France) in France) waswas observed in observed in some places. some places.

E. canadensisE. canadensisMyriophyllum spicatumMyriophyllum spicatum

→ Difficult to predict macrophyte invasion.

Further studies required for predictingFurther studies required for predictingmacrophytemacrophyte invasions.invasions.

To explain the mechanisms of invasions, we To explain the mechanisms of invasions, we need :need :

1. to improve our knowledge on the characteristics of invading species, and

2. on those of the ecosystems invaded3. to investigate the relationships between these 2

factors,4. or to study the invasion process in time.