effects of freshwater river discharge on terrestrial arthropods in

EFFECTS OF FRESHWATER RIVER DISCHARGE ONTERRESTRIAL ARTHROPODS IN ATLANTIC AND

MEDITERRANEAN SANDY SHORES

byColombini I., Chaouti A., Fallaci M., Gagnarli E., Scapini F.,

Bayed A. and Chelazzi L.

Medcore Project International Conference

Florence 10th – 14th November 2005

MEDCORE PROJECT

(ICA3-CT2002-10003, 5° FP, INCO-MED Programme)

“FROM RIVER CATCHMENT AREAS TO THE SEA: A COMPARATIVE AND INTEGRATEDAPPROACH TO THE ECOLOGY OF MEDITERRANEAN COASTAL ZONES FOR

SUSTAINABLE MANAGEMENT”

BILATERAL PROJECTITALY – MOROCCO

CNR - CNRST AGREEMENT2002-2005

“SMALL-SCALE SPATIAL DISTRIBUTION OF MACROFAUNA ALONG ATLANTIC ANDMEDITERRANEAN SANDY SHORES”

Université Mohammed V –Agdal

Institut Scientifique

MAIN QUESTIONSMAIN QUESTIONSADDRESSED IN THE STUDYADDRESSED IN THE STUDY

• How do freshwater runoffs influence the communitystructure of terrestrial macroinvertebrates of sandybeaches?

• Are biologicaI descriptors, such as species richness,diversity and abundance, influenced by increasingdistances from freshwater discharges?

• Do gradients of physical factors change at increasingdistances from the river mouth?

0 1000 km

LOCATION OF SITESLOCATION OF SITES

Both beaches were:

• exposed• intermediate (sensu Short, 1996)• low quantities of beach-cast material• similar climatic regimes• similar fluvial outputs• small latitudinal differences• high human impact around river mouths

Main differences were:

• beach stability• tidal regimes: microtidal vs mesotidal excursions (Italiansite tidal range ≤ 40 cm; Moroccan site tidal range up to3.7 m during spring tide).• sea influence

Criteria for choice of sites

Italian site

Moroccan site

Dominant marine currents

ITALIAN SITE:ITALIAN SITE: Maremma Maremma Regional Park Regional Park

Ombrone river mouth

MOROCCAN SITE:MOROCCAN SITE: Mehdia Mehdia beach beach

Station 1

Station 2

Station 4

Station 5

ITALY: STATIONS FROM THE RIVER MOUTHITALY: STATIONS FROM THE RIVER MOUTH

Station 3

Sebou river mouthStation 1

Station 2

Station 3

Station 4

Station 5

MOROCCO: STATIONS FROM THE RIVER MOUTH MOROCCO: STATIONS FROM THE RIVER MOUTH

SAMPLING METHODSSAMPLING METHODS

Arthropod sampling (Transects with pitfall traps)

Environmental samples

beach slope and width

beach penetrability

sand samples(sand moisture, salinity, pH, total

organic matter, grain size)

RESULTS RESULTS

Beach slope and width

MaremmaMaremma Regional Park Regional Park

0 m2468101214161820222426283032343638

2 m0.5 m

2.7 %

10.2 %

2.4 %

2.2 %

0.6 %

dune scarp

sea land4042

Station 1

Station 2

Station 3

Station 4

Station 5

Sept 2002

9.7 %

9.8 %

3.8 %

1.8 %

1.6 %

May 2003

RESULTS RESULTS

12.9 %

17.5 %

16.8 %

21.2 %

13.5 %

June 2003

0 m2468101214161820222426283032343638sea land4042444648

dune scarp

11.1 %

11.9 %

17.3 %

10.0 %

13.0 %

Station 1

Station 2

Station 3

Station 4

Station 50.5 m2 m

Beach slope and widthOct 2002

MehdiaMehdia beach beach

RESULTSRESULTS

Sand parameters


May 2003

Sand size (ϕ)

1.5

2

2.5

3

1 2 3 4 5stations

Penetrability (mm)

304050607080

1 2 3 4 5stations

Salinity (µScm-1)

200300400500600700800900

1 2 3 4 5stations

pH

88.28.48.68.8

99.29.49.69.810

1 2 3 4 5stations

Sand moisture (%)

0123456

1 2 3 4 5stations

Organic matter (%)

1

1.5

2

2.5

3

1 2 3 4 5stations

Organic matter (%)

1

1.5

2

1 2 3 4 5stations

September 2002

Sand moisture (%)

0123456

1 2 3 4 5stations

pH

8.48.68.8

99.29.49.6

1 2 3 4 5stations

Salinity (µScm-1)

0100200300400

1 2 3 4 5stations

Penetrability (mm)

304050607080

1 2 3 4 5stations

Sand size (ϕ)

1

1.5

2

2.5

1 2 3 4 5stations

RESULTSRESULTS

Sand parameters


October 2002

Organic matter (%)

1

1,5

2

2,5

1 2 3 4 5stations

Sand moisture (%)

01234567

1 2 3 4 5stations

pH

8,68,89

9,29,49,69,810

1 2 3 4 5stations

Salinity (µScm-1)

0100200300400500

1 2 3 4 5stations

Sand size(ϕ)

1,6

1,8

2

2,2

1 2 3 4 5stations

Penetrability (mm)

354045505560

1 2 3 4 5stations

June 2003

Sand size (ϕ)

1,6

1,8

2

2,2

1 2 3 4 5stations

Penetrability (mm)

45

55

65

75

85

1 2 3 4 5stations

pH

8,68,8

99,29,49,69,810

1 2 3 4 5stations

Salinity (µScm-1)

0100200300400500

1 2 3 4 5stations

Organic matter (%)

1

1,5

2

2,5

1 2 3 4 5stations

Sand moisture (%)

01234567

1 2 3 4 5stations

RESULTSRESULTS

TOTAL CAPTURESn

0

2000

4000

6000

8000

1 2 3 4 5 stations

September 2002 n=11354May 2003 n= 6430


0

1000

2000

3000

4000

5000

6000

1 2 3 4 5

n

stations

October 2002 n= 3909June 2003 n=14337


Talitrus saltator

Phaleria provincialis

Tylos europaeus

September May

9.27 % 25.19 %

14.75 % 7.10 %

72.92 % 49.63 %

97.89% 87.32 %

Other Coleoptera 0.95 % 5.42 %

Talorchestia spinifera

Phaleria cadaverina

Talorchestia sp

October June

3.40 % 2.23 %

2.48 % 0.17 %

1.18 % 0.50 %

93.37 % 93.18 %

Other Coleoptera 1.59 % 3.69 %

Talitrus saltator

Talorchestia deshayesii

Tylos europaeus

0.08 % 0 %

56.89 % 24.13 %

22.05 % 58.85%

Talorchestia brito 5.70 % 3.61 %

RESULTSRESULTS

MaremmaMaremma Regional Park Regional Park MehdiaMehdia beach beach

MAIN CAPTURED SPECIES

Maremma Regional Park Mehdia beach

0100

200300400

500600

700800

station 1 station 2 station 3 station 4 station 5

n

Sept n=1160May n=2235

Abundance n=3395

n

0100

200300400

500600

700800


Oct n=195June n=844

Abundance=1039

Species Richness n=94

05

1015202530354045


n

Oct n=24June n=77

Species Richness n=55

05

1015202530354045


n

Sept n=15May n=49

Abundance and species richness of Coleoptera atincreasing distance from the river delta

RESULTS RESULTS

>

<

Diversity indices (Coleoptera)

September 2002 May 2003 TotalStations 1 2 3 4 5 1 2 3 4 5 Sept May α sup. l. 1.18 1.31 0.93 1.19 2.68 0.73 3.44 6.02 6.37 5.84 2.72 9.41α diversity 0.93 1.07 0.8 1.02 2.27 0.58 3.03 5.67 5.51 5.25 2.43 8.85α inf. l. 0.68 0.83 0.66 0.84 1.86 0.43 2.62 5.15 4.65 4.65 2.15 8.03β diversity 0.11 0.02 0.05 0.02 0.01 0.01 0.12 0.08 0.05 0.03Brillouin 0.45 0.41 0.29 0.25 0.83 0.13 0.61 0.96 1.55 1.59 0.44 1.28Pielou 0.35 0.27 0.18 0.14 0.38 0.12 0.23 0.03 0.05 0.53 0.17 0.34Simpson 0.76 0.08 0.88 0.09 0.62 0.94 0.74 0.64 0.39 0.32 0.83 0.53

RESULTSRESULTS


October 2002 June 2003 TotalStations 1 2 3 4 5 1 2 3 4 5 Oct Juneα sup. l. 1.59 2.47 18.19 2.69 8.23 4.65 14.45 10.99 16.62 13.64 8.15 21.97α diversity 1.19 1.92 13.93 2.13 6.45 4.09 12.40 9.52 14.96 12.00 7.19 20.61α inf. l. 0.79 1.36 9.67 1.57 4.67 3.52 10.35 8.04 13.30 10.35 6.24 19.25β diversity 0.02 0.10 0.03 0.002 0.05 0.07 0.11 0.12 0.003 0.06Brillouin 0.40 0.65 1.81 0.60 1.66 1.01 2.18 2.30 2.01 2.20 1.38 2.31Pielou 0.32 0.41 0.84 0.34 0.81 0.37 0.76 0.81 0.59 0.71 0.47 0.56Simpson 0.77 0.66 0.14 0.70 0.17 0.55 0.14 0.10 0.24 0.16 0.47 0.20


RESULTSRESULTS

Simple linear regression analysis


September 2002

2230 5990

September 2002

2230 5990

Sand moisture (%)

Salinity (µS/cm)

pH

Organic matter (%)

Penetrability (mm)

Beach slope (% )

Beach width (m)

Mz (φ)

σI (φ)

SkI

KG

m from delta

Total arthropods (n)

Tylos europaeus ad. (n)

Tylos europaeus juv. (n)

Talitrus saltator ad. (n)

Talitrus saltator juv. (n)

Coleoptera (n)

Coleoptera spp (n)

α div. (Coleoptera)

β div. (Coleoptera)

m from delta

Phaleria provincialis ad. (n)Phaleria provincialis l. (n)

Arctosa perita

May 2003

2230 5990

May 2003

2230 5990

RESULTS RESULTS

Simple linear regression analysis


October 2002

50 5720

October 2002

50 5720

Sand moisture (%)

Salinity (µS/cm)

pH

Organic matter (%)

Penetrability (mm)

Beach slope (% )

Beach width (m)

Mz (φ)

σI (φ)

SkI

KG

m from delta

Total arthropods (n)Tylos europaeus ad. (n)

Tylos europaeus juv. (n)Talitrus saltator ad. (n)

Talitrus saltator juv. (n)

Coleoptera (n)

Coleoptera spp (n)

α div. (Coleoptera)β div. (Coleoptera)m from delta

Phaleria cadaverina ad. (n)

Talorchestia brito juv. (n)

Talorchestia brito ad. (n)

Talorchestia spinifera juv. (n)Talorchestia spinifera ad. (n)

Phaleria cadaverina lar (n)

Labidura riparia

June 2003

50 5720

June 2003

50 5720

May

RESULTS RESULTS

Long-shore distribution of most abundant species


3.500 4.000 4.500 5.000 5.500 6.000

m from the river mouth

P. provincialis ad

T. europaeus j T. europaeus ad.

T. saltator ad.

T. saltator j.

P. provincialis larvae

A. perita

3.000

Station 2 Station 3 Station 4 Station 5

Sept

RESULTSRESULTS MehdiaMehdia beach beach

Long-shore distribution of most abundant species

June

0 6000

P. cadaverina ad

T. europaeus j T. europaeus ad.

T. saltator adT. saltator j

0

m from the river mouth

6000

P. cadaverina larvae

T. brito ad

T. brito jT. spinifera ad

T. spinifera jT. sp ad

T. sp j

L. riparia

Station 1 Station 2 Station 3 Station 4 Station 5

1000 2000 3000 4000 5000

Oct

RESULTSRESULTS

Multiple regression analysis

ß div. (Cole.) +

moist.(%)

Sal.(µS/cm)

pH O. mat.(%)

Pen.(mm)

slope (%)

width(m)

Mz (φ)

S M S M S M S M S M S M S M S M

Total arthropods + + + +

T. europaeus ad. – – + – + +

T. europaeus j. + +

T. saltator ad. + + + +

T. saltator j. + + + +

Coleoptera + + –

Coleoptera spp –

P. provincialis ad + + –

α div. (Cole.) – – +

R2

S M

0.992

0.989

0.769

0.989

0.993

0.969

0.767

0.958

P. provincialis l. + + + 0.952

0.874

0.890


+ – + –+ – + + – –+ – + – –

+

+ – + –– – –

– + – + –

– – –

– + + – ––

0.965

0.816

0.992

0.956

0.958

0.873

0.987

0.878

–– – – + + – 0.997

0.974

0.444

0.603

0.939

0.333

0.750

0.834

0.729

0.992

0.536

0.597

0.389

0.580

0.942

0.628

0.533

0.804

O

R2

-+ß diversity (Cole.)

-++--α diversity (Cole.)

+Phaleria cadaverina lar.

-+Phaleria cadaverina ad.

+Coleoptera spp

--++Coleoptera

-+++-+Labidura riparia

Talorchestia sp ad.

Talorchestia spinifera juv.

+Talorchestia spinifera ad.

--+Talorchestia brito juv.

+-Talorchestia brito ad.

++Talitrus saltator juv.

+--Talitrus saltator ad.

-+Tylos europaeus juv.

-Tylos europaeus ad.

-+Total arthropods

JJOJOJOJOJOJOJOJO

Mz (φ)width(m)

Slope (% )

Pen.(mm)

O. mat (%)

pHSal.(µS/cm)

Moist(%)

MehdiaMehdia beach beachRESULTS RESULTS Multiple regression analysis

0.428--0.976---+++-0.770++++0.915++-++0.861-+0.918--+-++0.958+---+0.769--+0.987-++-++

0.326-

0.494---0.813

0.693-+0.704+--+0.553-

Forcing factors in ecosystem functioning

Maremma Regional Park(closed system)

OMBRONEriver

low sedimentinput

INSTABILITYerosion and progradation

processes

Mediterranean coast

Higher sand moisturesand salinities, lowerpenetrability withincreasing distance

Arthropods increased with distance from river(isopods & amphipods)

Amelioration ofbeach-dune features

Lowerhuman impact

Changes in beach slope andwidth according to theseason & distance

Finer sand transportedby dominant NS marinewater currents

Seasonal changes of pH under direct influence of river

Station 3Dynamic

equilibrium

Highest species richness

α diversity

Increased habitatdiversity

Species long-shore distribution seasonal shifts

Human disturbance

Species preference for certain beach

features

CONCLUSIONSCONCLUSIONS

Forcing factors in ecosystem functioning

Mehdia beach(open system)

Oceanheavy wave action

&high tidal excursions

Atlantic coast

Octoberno linear trends with distance (except for pH and sand size)

Finer sand, higher pH,greater organic matter atstation 2

Differences in sand parametersdue to season and heavy rain

Weak long-shore drift thatdeposited fluvial sedimentsnear river mouth

Amphipods and Coleoptera species:significant linear trends with distance in June

Higher number of Amphipod species(Talorchestia species)

Preferences to specific beach features

June higherspecies richness

α diversity of Coleoptera

Allocthonous flying species fromdune blown by eastern winds

Higher α diversitycompared to Maremma

Shifts in species long-shore distributionbetween seasons

Well developed beach dune system &high environmental complexity with

diverse vegetation cover

CONCLUSIONSCONCLUSIONS

Sidi Bou Ghabaretro-dune water basin

Oued Sebou

Junelinear trends with distance

Human disturbance

THANK YOU

effects of freshwater river discharge on terrestrial arthropods in

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