DISPERSAL ASSEMBLY RULES IN DUTCH PLANT COMMUNITIES ?

Wim Ozinga

• KUN: Prof. Jan M. van Groenendael• RUG: Prof. Jan P. Bakker

Dr. Renée M. Bekker• Alterra: Dr. Joop H.J. Schaminée

Drs. Stephan M. Hennekens

Disappointing results nature restoration projects ‘missing target species’

Constraints on assembly of local communities: (a)biotic Dispersal

BACKGROUND

Importance of dispersal in determining species composition:

Species levelinterspecific differences traits, trade-offs

Community level+ environmental constraints on efficiency dispersal vectors (trait-environment linkages)

Landscape level+ spatial configuration, availability dispersal vectors

DISPERSAL ASSEMBLY ?

TRAIT – ENVIRONMENT LINKAGES

APPROACH

Combination of 2 large databases:

Vegetation database

Database dispersal traits

Vegetation relevés (N=40.000)

Synoptic tables170 plant communities (only inland, terrestrial)

each community: species + % sites occupied

Ordination main environmental gradients:

1. water availability

2. productivity

3. light availability

DUTCH VEGETATION DATABASE

IRIS: DATABASE ON REPRODUCTIVE TRAITS

Focus on long distance dispersal (>100 m)• Wind (anemochory)

• Water (hydrochory)

• Herbivores, fur (epizoochory)

• Herbivores, internal (endozoochory)

• Birds (ornithochory)

Dispersal in time• Seed longevity

www.synbiosys.alterra.nl/IRIS

IRIS: DATABASE ON REPRODUCTIVE TRAITS

Luzula multiflora

0

10

20

30

40

50

60

70

80

90

100

0 168 336 504 672 840time (hours)

flo

ati

ng

se

ed

s %

still water

stirring water

T50

Floating seedlings

Example contents

IRIS: DATABASE ON REPRODUCTIVE TRAITS

Focus on long distance dispersal (>100 m)• Wind (anemochory)

• Water (hydrochory)

• Herbivores, fur (epizoochory)

• Herbivores, internal (endozoochory)

• Birds (ornithochory)

Dispersal in time• Seed longevity

Rough classification species for each dispersal vector:• 0: low potential for long distance dispersal• 1: relatively high ,,

www.synbiosys.alterra.nl/IRIS

Matrix 1

win

d

wat

er

mam

mal

s, e

xter

nal

mam

mal

s, in

tern

al

bir

ds

po

lych

ory

1 1 1 0 0 0 Σ=22 0 0 1 0 0 Σ=13 0 0 1 1 1 Σ=34 0 0 0 0 0 Σ=0

ΣΣ

n=900 Σ

Long-distance dispersal potential

Sp

ecie

s

DATABASE LINKAGES

Matrix 2

mo

istu

re

pro

du

ctiv

ity

ligh

t

1

n=900

Environment

Sp

ecie

s

Species level Community levelD

ispe

rsal

tra

itsE

nviro

nmen

t

Matrix 1w

ind

wat

er

mam

mal

s, e

xter

nal

mam

mal

s, in

tern

al

bir

ds

po

lych

ory

1 1 1 0 0 0 Σ=22 0 0 1 0 0 Σ=13 0 0 1 1 1 Σ=34 0 0 0 0 0 Σ=0

ΣΣ

n=900 Σ

Long-distance dispersal potential

Sp

ecie

s

Matrix multiplications Combination

Matrix 5

mo

istu

re

pro

du

ctiv

ity

ligh

t

1

n=123Co

mm

un

ity

Environment

Matrix 4

win

d (

%)

wat

er (

%)

mam

mal

s, e

xt. (

%)

mam

mal

s, in

t. (

%)

bir

ds

(%)

po

lych

ory

(av

g.)

1

n=123Co

mm

un

ity

Long-distance dispersal potential

win

d (

%)

wat

er (

%)

mam

mal

s, e

xt. (

%)

mam

mal

s, in

t. (

%)

bir

ds

(%)

po

lych

ory

(av

g.)

moisture Σproductivity Σlight availability Σ

Trait-environment patterns

Long-distance dispersal potentialMatrix

3 1 n=1231

n=900

Sp

ecie

sCommunity

170 plant communities

R2 = 0.91p < 0.001

0

20

40

60

80

3 4 5 6 7 8 9 10 11 12

moisture

% h

ydro

cho

rou

s sp

ecie

s

Acquatic communities

excluded

DISPERSAL BY WATER

Aquatic

DISPERSAL BY WIND

R2 = 0.329p < 0.001

0

20

40

60

1 2 3 4 5 6 7 8

productivity

% a

nem

och

oro

us

spec

ies

DISPERSAL BY HERBIVORES (FUR)

R2 = 0,411p < 0,001

20

30

40

50

4 5 6 7 8

light availability

% e

piz

oo

cho

rou

s sp

ecie

s

DISPERSAL BY HERBIVORES (DUNG)

R2 = 0,527p < 0.001

60

70

80

90

100

4 5 6 7 8

Light availability

% e

nd

ozo

och

oro

us

spec

ies

SEED LONGEVITY

R2 = 0,33p<0,001

30

40

50

60

70

80

90

100

4 5 6 7 8

light availability

% s

pec

ies

wit

h p

ersi

sten

t se

eds

SHIFT IN DISPERSAL TRAITS

endozoochory

R2 = 0,527

0

20

40

60

80

100

4 5 6 7 8

light availability

% s

pec

ies

ornithochory

R2 = 0.14

myrmecochory

R2 = 0.48

anemochory

R2 = 0,14

epizoochory

R2 = 0.41

seedbank

R2 = 0.33

DISPERSAL TRAITS WITHIN A COMMUNITY

Trait spectrum broad leafed forest (Carpinetum)

10

15

20

25

30

35

40

45

NO

WATER

WIN

D

HERBIVORES

BIRDS

SEEDBANK

% S

PE

CIE

S (N

=3

18

)

LIGHT AVAILABILITY & POLYCHORY

R2 = 0,37p < 0.001

1,0

1,5

2,0

2,5

3,0

4 5 6 7 8

light availability

# d

isp

ersa

l vec

tors

/ sp

ecie

s

Spectra of dispersal traits change along main environmental gradients (especially along light gradient)

dispersal models should include habitat quality

Within community diversity of dispersal traits dispersal models should include multiple dispersal vectors

Relative importance of long distance dispersal increases along light gradient

communities probably differ in sensitivity for habitat fragmentation and in potential for ecological restoration

CONCLUSIONS