stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stress: 0.1732stre

ABO

BBE

CRI

DVU

EEN

HGUKPA

LAU LRALSA

NOP

PCA

PMA

PMI

SAB

SAC

SAU

SME

SPA

SPI

STYZOP

ZZE

GNI

APFA

−1

0

1

−1.5 −1.0 −0.5 0.0

nmds1

nmds

2

0.5 1.0

Restoration sites

Reference sites

Increasing habitat structure

C. nodosa Z. marinaN. noltii

Barebottom

Indicator species in Z. marina and N. noltii meadows:- Salaria pavo (Blennidae)- Syngnathus typhle (Syngnathidae)

Indicator species in C. nodosa meadows:- Gobius niger (Gobiidae)- Nerophis ophidion (Syngnathidae)- Zosterisessor ophiocephalus (Gobiidae)

0.0

0.2

0.4

0.6

0.0

0.1

0.2

0.3

0.4

0.5

0

200

400

600

2

4

6

8

Total number of species

Total density (individuals/100 m2)

Rest

orat

ion

C. nod

osa

Z. m

arin

a

N. n

oltii

Rupp

ia sp

.ba

re b

otto

m

Refe

renc

e

Rest

orat

ion

C. nod

osa

Z. m

arin

a

N. n

oltii

Rupp

ia sp

.ba

re b

otto

m

Refe

renc

e

Number of indicator species/total number of species ratio

Density of indicator species/total density ratio

Site typology Habitat typology Site typology Habitat typology

p-value < 0.05

p-value < 0.001

p-value < 0.001

p-value < 0.001

p-value < 0.001

p-value < 0.05

st.05st.01

st.12

st.15

st.10

st.08

st.17

st.16

ref.01

ref.02

ref.03

ref.04

ref.05ref.06

ref.07

ref.08

ref.09

Restoration sitesEight newly-transplanted sites from the SeResto project were monitored in spring and autumn 2014. Bare substratum was the main habitat type, with scattered natural patches of Z. marina, N. noltii and Ruppia sp. already present in some sites.

Natural seagrass meadows were considered as reference sites (five sites in spring and seven in autumn). All the

three main species of seagrass were found:

Reference sites

Cymodoceanodosa

Nanozostera noltii

Zostera marina

The LIFE project N° LIFE12 NAT/IT/000331 - SeResto started in 2014 with the objective of restoring seagrass meadows in the northern Venice lagoon (northern Adriatic Sea, Italy). An expected goal of the project is the enhancement of the overall ecological status (sensu Dir. 2000/60/EC; WFD) of the northern lagoon, and thus also to restore the fish communities associated with seagrass meadows. Aim of this work was to identify characteristics of the fish assemblage most associated with reference habitats, and test them as potential indicators to track restoration progress towards desired conditions.

Fish were caught by seine nets and compared between seagrass restoration and natural meadow sites, using the latter as reference. Both spring and autumn 2014 observations were considered. Natural habitat typology (either C. nodosa-meadow, Z. marina-meadow, N. noltii-meadow, Ruppia sp.-meadow or bare bottom) was recorded.A fish-based multimetric index was developed and applied to assess the ecological status. A 2-way PERMANOVA based on Bray-Curtis similarity was employed to test the effect of seasonality and site typology on community structure.Fish species mostly associated with reference seagrass meadows were then identified, and a set of metrics was computed considering both the whole community and indicator species. The effects of site and habitat typology were studied on each metric separately by means of a univariate PERMANOVA using Euclidean distance.

Four attributes of fish community were selected for their sensitiveness to anthropogenic pressures and aggregated in the Habitat Fish Bioindicator Index, a habitat-, season- and water body-specific multimetric tool to assess the ecological status of Venice lagoon in compliance with Water Framework Directive (Zucchetta et al., in preparation). Ecological status in newly-transplanted sites is lower than that of natural meadows, suggesting that a successful restoration of seagrass habitat could increase the quality of fish assemblages in the project area.

Ruppia sp.

Lagoon residents in black, other species in gray

Whole-community metrics Metrics based on indicator species:G. niger, N. ophidion, S. pavo,

S. typhle, Z. ophiocephalus

0.00

0.25

0.50

0.75

1.00

Reference Restoration

Site typology

Scor

es o

f Hab

itat F

ish

Bioi

ndic

ator

Inde

x

Moderate

Poor

Bad

Fish community is significantly different between restoration and reference sites (p-value <0.001) and between seasons (p-value <0.05), as shown in nMDS. From bare, unstructured habitats, that are still prevalent in restoration sites and support species like Aphanius fasciatus (APFA), Knipowitschia panizzae (KPA) and Pomatoschistus marmoratus (PMA), fish community changes along progressively more structured habitats, i.e. from short- and narrow-leaved Ruppia sp. and N. noltii meadows, to taller- and broader-leaved C. nodosa and Z. marina meadows. Reference sites support indeed high densities of seagrass specialists, with also Gobius niger (GNI) and Salaria pavo (SPA) being strongly linked to seagrass habitats.

Total number of species in fish community is significantly lower in restoration sites compared with natural meadows, while no significant differences are found in total density. Proportion of indicator species selected from nMDS analysis (both in terms of density and species number) is significantly related to site typology, showing lower values in newly-transplanted sites. Moreover, both metrics based on indicator species show significantly increasing values at increasing levels of habitat structure.

The application of a multimetric index showed that restoring seagrass habitat in the northern Venice lagoon could enhance the ecological status of fish fauna in this area, which has undergone substantial anthropogenic alterations in last decades. In order to verify such hypothesis, monitoring of seagrass specialists such as Syngnathus typhle, Nerophis ophidion and Zosterisessor ophiocephalus (Franzoi et al., 2010), but also of Gobius niger and Salaria pavo, could be used to track restoration development and assess its success. Results also suggest that not all plant species form equivalent habitats for fish. Different fish assemblages may colonise habitats recreated with either the tall- and broad-leaved Cymodocea nodosa or the shorter- and narrower-leaved Nanozostera noltii. Hence, different endpoints in fish communities of restored habitats are expected.

#2. Total density of biomass

#3. Number of lagoon resident species

#4. Mean individual weight of benthivorous species

#1. Margalef’s richness of hyperbenthivorous/zooplanctivorous/piscivorous species (calculated on biomass)

High

Good

USING FISH COMMUNITY TO IDENTIFY SUCCESS CRITERIA FOR SEAGRASS HABITAT RESTORATIONScapin L.*, Zucchetta M., Facca C., Sfriso A., Franzoi P.

METHODS

RESULTS

CONCLUSIONS

Venice Lagoon

www.lifeseresto.euFranzoi P., Franco A., Torricelli P. (2010). Fish assemblage diversity and dynamics in the Venice lagoon. Rendiconti Lincei, 21(3), 269–281. http://doi.org/10.1007/s12210-010-0079-zZucchetta M., Franco A., Scapin L., Ciccotti E., Torricelli P., Franzoi P. Uncertainty in developing fish-based multimetric indices (in preparation).

The LIFE12 NAT/IT/000331 - SEagrass RESTOration project is funded by European Union's LIFE+ financial instrument and contributes to the environmental recovery of a Natura 2000 site (SIC IT3250031 - Northern Venice Lagoon).

CEMAS - DAIS, Università Ca’ Foscari Venezia, via Torino 155, 30170 Venezia, Italy. *luca.scapin@stud.unive.it

Life SeResto

REFERENCES