Amphibia-Reptilia 28 (2007): 517-529

Diversity, ecological structure and conservation of herpetofauna in aMediterranean area (Dadia National Park, Greece)

Vassiliki Kati1,*, Johannes Foufopoulos2, Yiannis Ioannidis3, Haritakis Papaioannou1,

Kostas Poirazidis4, Philippe Lebrun5

Abstract. The current study attempts to explore the diversity patterns and the ecological structure of herpetofauna inorder to provide a guideline for its conservation management, taking as case study the Dadia national park, in Greece.We surveyed 36 sites by conducting time constraint visits and random transects to sample semi-aquatic (amphibiansand freshwater terrapins) and terrestrial (lizards and terrestrial tortoises) herpetofauna respectively. We recorded 20herpetofauna taxa, including five protected species. The park authorities should maintain brooks as a high priority habitatfor semi-aquatic herpetofauna, periodically flooded land and lowland streams as important habitats, and to a lesserdegree anthropogenic wet habitats. Semi-aquatic species have narrow habitat requirements related to substrate type andhumidity. Terrestrial herpetofauna species are influenced by the degree of shade and the type of substrate; they favoura diversity of semi-open habitats (open oakwoods, heaths), located in the buffer zone rather than in the core of thepark that contains densely forested habitats. Management focusing on raptors, the initial conservation priority of thenational park, is compatible with the conservation of the terrestrial herpetofauna, as the proposed maintenance of anopen forest structure is beneficial for terrestrial herpetofauna as well. Our research indicates that future managementprograms will have to address the needs of herpetofauna species independently and that they should also be integratedin the monitoring programme of the park, with emphasis on the conservation status and trend of the five protectedspecies.

Keywords: amphibians, conservation, ecological structure, management, human land use, reptiles.

Introduction

Amphibian diversity is in rapid decline world-wide for a number of different causes includinghabitat loss and fragmentation, climate change,environmental contamination, as well as theinvasion of exotic species, including patho-gens (Alford and Richards, 1999; Blaustein andKiesecker, 2002; Stuart et al., 2004; Araujo

1 - University of Ioannina, Department of Environmentaland Natural Resources Management, Seferi 2, 30100Agrinio, Greece

2 - University of Michigan, School of Natural Resourcesand Environment, Dana Building, 440 Church St. AnnArbor, MI 48109-1041, USA

3 - The Goulandris Natural History Museum, Levidou 13,GR-14562 Athens, Greece

4 - WWF Greece, Dadia project, GR-68400, Dadia, Soufli,Greece

5 - Université catholique de Louvain, Unité d’Écologie etde Biogéographie, Centre de Recherche sur la Biodi-versité, Place Croix du Sud, 5, 1348 Louvain-la-Neuve,Belgium*Corresponding author; e-mail: vkati@cc.uoi.gr

et al., 2006; Cushman, 2006; Pounds et al.,2006). For these reasons, amphibians have be-come the foci of many national conservationpolicies and research projects (e.g. Denton etal., 1997; Young et al., 2001; Foster and Bee-bee, 2004). Reptiles face similar suites of prob-lems and a number of taxa are experiencing se-vere range reductions and declines in abundance(Gibbons et al., 2000; Araujo et al., 2006).Furthermore, reptiles can be sensitive indica-tors of the impact of human activities suchas intensive grazing, forest cutting and burn-ing, and mining areas restorations (e.g. McLeodand Gates, 1998; Read, 2002; Thompson andThompson, 2005; Wilgers and Horne, 2006).Thus, it is imperative to develop efficient man-agement plans and monitoring schemes on mul-tiple spatial scales for both amphibians and rep-tiles (e.g. Buckley and Beebee, 2004; Ficetolaet al., 2004).

The present study took place in Dadia Na-tional Park, in northeastern Greece, which was

© Koninklijke Brill NV, Leiden, 2007. Also available online - www.brill.nl/amre

518 V. Kati et al.

originally established to conserve a great diver-sity of birds of prey (36 out of the 38 Europeanspecies) and in particular a breeding populationof black vultures (Aegypius monachus), the flag-ship species of the National Park (Poirazidis etal., 2004). However, the broader area of the Na-tional Park also holds a particularly rich her-petofauna (40 species) and for that reason ithas been proposed as a “biogenetic reserve”(Helmer and Scholte, 1985). In the presentstudy, we use the term “semi-aquatic herpeto-fauna” to communally refer to amphibians andto one reptile group – the freshwater terrap-ins. The term “terrestrial herpetofauna” refersto lizards and terrestrial tortoises. Our studyaims to advance the existing knowledge of rep-tile and amphibian management, while simul-taneously exploring the impact of human ac-tivities on these species and assessing the effi-ciency of the existing strictly protected zonesto conserve herpetofauna diversity. More pre-cisely, our objectives were: (a) to investigatethe diversity patterns of the semi-aquatic andterrestrial herpetofauna in Dadia National Park,(b) to give an insight of their ecological struc-ture and adequate habitats, so as (c) to pro-vide an informed guideline for the conservationmanagement of the above groups. Our resultscan have an extrapolative value for the conser-vation management of the amphibian and rep-tile community in other Mediterranean areas aswell.

Methods

Study area

The study area is a hilly area (10-650 m elevation a.s.l.)with a sub-Mediterranean climate, situated in north-easternGreece (longitude 26◦00′-26◦19′ and latitude 40◦59′-41◦15′) (fig. 1). It is a forest complex extending over430 km2 and being characterized by extensive pine (Pi-nus halepensis brutia, P. nigra) and oak (Quercus frainetto,Q. cerris, Q. pubescens) forests. The National Park areaincludes two core areas that are strictly protected (72.9km2) and have 85% cover of pinewoods and mixedpine-oak woods, and one buffer zone (351.7 km2) with72% forest cover, including more open or semi-open ar-eas.

Sampling

We selected 36 sites out of which 30 were located insidethe National Park, in a stratified random way, in order torepresent the 21 vegetation types in the study area, usingthe CORINE typology database (Devillers and Devillers-Terschuren, 1996) (table 1). In two cases (CORINE 41.733and 42.85A), we further distinguished two vegetation sub-categories, on the basis of vegetation physiognomy (bushyundergrowth or not). Semi-aquatic species were recordedby conducting four time-constraint visits of 30, 160, 30and 30 minutes respectively (Crump and Scott, 1994). Dur-ing the first visit (30 March-20 April 1999) we identi-fied species acoustically in the time period from sunsetto two hours afterwards, which coincides with the peakof amphibian calling activity (Zimmerman, 1994; Roché,1997). All other visits were conducted during spring day-time hours from 30 March to 15 June of the same year(1999). Species were identified visually (adults, larvae, eggmasses) and the type of their wet microhabitat was de-scribed (brook, ditch, humic substrate, inundated land, low-land stream, puddle, well, wet grass: table 2). We sampledthe terrestrial herpetofauna by conducting one random tran-sect per site, where we counted the number of individu-als along a corridor of 300 m length and 6 m total width(Krebs, 1989). We excluded snakes from terrestrial herpeto-fauna group because their cryptic character, long period ofinertia and low density demands more intensive sampling,different from transects (Seigel et al., 1993). We consideredthe two species of green lizard (Lacerta viridis and L. tri-lineata) as one taxonomic group, due to the difficulty ofvisually identifying adult specimens without capture (Frör,1979). We repeated this sampling protocol three times dur-ing spring and early summer (15 April-11 May, 16-31 Mayand 1-16 June 1999), when air temperatures ranged be-tween 16◦ and 30◦C. This ensured standardized samplingefficiency at similar levels of species activity. We also es-timated the degree of shade from low (<0.5 m height) aswell as from higher bushes and trees (>0.5 m height), bycalculating the percentage of the area occupied by the ver-tical projection of vegetation in the transect corridor, us-ing the following vegetation cover classes: 1-5%, 6-25%,26-50%, 51-75% and >75% (Küchler, 1988). We also re-corded the type of substrates occurring along the transect(grass, humus, oak leaves, needles, rocks, bare soil, sand,stones).

Data analysis

Since we sampled semi-aquatic herpetofauna in a qualita-tive way and terrestrial herpetofauna in a semi-quantitativeway, we produced two respective matrices. Both matriceswere crossing species with sites, but the matrix of terres-trial herpetofauna had as a cell value the maximum num-ber of individuals recorded during the three sampling sea-sons. We estimated the diversity of each site by calculat-ing species richness (S) as well as Shannon diversity in-dex (H ′) for the terrestrial herpetofauna. The communitycomposition was analyzed using the R3 software package(Legendre and Vaudor, 1991). We produced a similarity

Herpetofauna diversity and conservation 519

Figure 1. Map of main vegetation types and study sites in the Dadia National Park (modified from Kati et al., 2004).

matrix of the sites using Sørensen and Steinhaus coeffi-cients of similarity for the binary and the semi-quantitativedata respectively. We ordinated sites across axes usingthe Principal Coordinate Analysis with corrected eigenval-ues (DistPCoA) (Legendre and Anderson, 1998) and wegrouped them into clusters using Ward’s minimum variancemethod.

Results

We sampled 10 species of amphibians andterrapins (Triturus vulgaris, Bombina varie-gate, Bufo viridis Bufo bufo Salamandra sala-mandra, Hyla arborea, Rana dalmatina, Rana

520 V. Kati et al.

Tabl

e1.

Site

desc

ript

ion

(veg

etat

ion

type

,wet

habi

tats

,tra

nsec

tsof

terr

estr

ialh

erpe

tofa

una)

and

dive

rsity

ofhe

rpet

ofau

na(s

peci

esri

chne

ss,S

and

Shan

non

dive

rsity

inde

xH

);th

enu

mbe

rin

pare

nthe

sis

indi

cate

the

prot

ecte

dsp

ecie

sof

Ann

exII

inD

ir.92

/43.

CO

RIN

E

vege

tatio

nty

peD

escr

iptio

nof

vege

tatio

nty

peSi

teco

deA

q.he

rpet

ofau

naTe

rres

tria

lHer

peto

faun

a

Sw

etha

bita

tsS

Hve

geta

tion

cove

r(%

)su

bstr

ate

type

(>0.

5m

heig

ht)

(<0.

5m

heig

ht)

Fore

sts

41.1

B×

41.1

9311

beec

hw

oods

F1a

1h

0–

5–

hm,l

(F)

F1b

1h

4(1

)1.

364

1hm

,l,g

41.7

6oa

kwoo

ds(Q

uerc

usfr

aine

tto/

cerr

is)

F2a

0–

20.

55

1g,

lF2

b0

–2

0.33

51

g,l

41.7

33ak

woo

ds(Q

uerc

uspu

besc

ens)

F3a

0–

5(1

)0.

864

2g,

l,s

F3b

0–

3(1

)1.

424

1l,

s,g

akw

oods

(Que

rcus

pube

scen

s)w

ithbu

shun

-de

rgro

wth

F4a

0–

7(1

)1.

813

3s,

st,g

,l

F4b

0–

7(2

)1.

563

3s,

g,st

,l43

.7m

ixed

pine

-oak

woo

dsF5

a0

–4

(1)

1.07

43

s,g,

l,n

F5b

4(1

)b

4(1

)1.

154

3s,

n,l,

g42

.661

(C)

pine

woo

ds(P

inus

nigr

a)F6

1w

g3

1.08

51

g,s,

n42

.85

Api

new

oods

(Pin

usbr

utia

)F7

0–

20.

645

1n

pine

woo

ds(P

inus

brut

ia)

with

bush

unde

r-gr

owth

F8a

0–

2(1

)0.

584

3s,

n

F8b

0–

3(1

)1.

13

3s,

n44

.514

ripa

rian

vege

tatio

n(A

lnus

glut

inos

a)F9

a3

(1)

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g2

0.69

5–

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F9b

3(1

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wg

20.

485

1sa

,g,s

t44

.615

ripa

rian

vege

tatio

n(P

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.)F1

0a5

l,w

g2

(1)

0.57

52

s,g

F10b

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wg

10

51

s,g

Shru

bs32

.313

high

maq

uis

(Arb

utus

sp.)

S1a

0–

0–

5–

s,l

(S)

S1b

0–

10

5–

s,l

32.1

61de

cidu

ous

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mat

tora

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0–

2(1

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693

3s,

st,g

,l32

.21A

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34.5

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shes

(Phy

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22

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Herpetofauna diversity and conservation 521

Tabl

e1.

(Con

tinue

d).

CO

RIN

E

vege

tatio

nty

peD

escr

iptio

nof

vege

tatio

nty

peSi

teco

deA

q.he

rpet

ofau

naTe

rres

tria

lHer

peto

faun

a

Sw

etha

bita

tsS

Hve

geta

tion

cove

r(%

)su

bstr

ate

type

(>0.

5m

heig

ht)

(<0.

5m

heig

ht)

Hea

ths

32.3

2lo

wer

icac

eous

maq

uis

Ha

0–

6(2

)1.

531

4s,

st,g

(H)

Hb

0–

6(2

)1.

411

5s,

st,g

Gra

ssla

nds

37.4

(×41

.822

1)hu

mid

gras

slan

dsG

1a3

d,p,

wg

3(1

)0.

962

g,s

(G)

G1b

2w

,wg

30.

912

g34

.53

xeri

cgr

assl

ands

G2a

0–

3(1

)0.

991

r,s,

gG

2b2

(1)

b4

(2)

1.28

1r,

s,g

34.2

serp

entin

egr

assl

ands

G3

0–

20.

691

r,g,

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gric

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land

82.1

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A1a

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2(1

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321

1G

(A)

A1b

5d,

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wg

2(1

)0.

21

1g

84.4

rura

lm

osai

cs(a

gric

ultu

ral

field

sw

ithhe

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)A

2a4

d,i,

p2

(1)

0.53

13

g

A2b

6(2

)b,

d,i,

p,w

g2

(1)

0.42

13

gM

osai

cs32

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×38

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eudo

maq

uis×

past

ures

M1a

2(1

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20.

513

3g,

s,st

(M)

M1b

3p

30.

653

4g,

st,s

32.7

1×

38.1

37.1

×44

.12

×41

.733

pseu

dom

aqui

s×

past

ures

×hu

mid

gras

s-la

nd×

will

owsh

rubs

×oa

kwoo

dsM

25

(1)

b,p,

wg

5(2

)0.

863

3g,

s

Tota

l19

2136

10

Wet

habi

tats

b:br

ook,

d:di

tch,

h:hu

mic

subs

trat

e,l:

low

land

stre

am,i

:inu

ndat

edla

nd,p

:pud

dle,

w:w

ell,

wg:

wet

gras

s(s

eeta

ble

2).T

rans

ectd

escr

iptio

n:sh

ade

(%):

1=

1-5,

2=

6-25

,3

=26

-50,

4=

51-7

5,5

=76

-100

,sub

stra

tety

pe:g

=gr

ass,

hm=

hum

ic,l

=de

adoa

kle

aves

,n=

need

les,

r=

rock

s,s

=ba

reso

il,sa

=sa

nd,s

t=st

ones

.

522 V. Kati et al.

Table 2. Types of aquatic microhabitats recorded in thedifferent sites.

Code Wet habitat Description

b brook non permanent flow, reduced topools in summertime, rocky orstony substrate, clear water

d ditch cement-constructed to irrigate theagricultural fields, deep with vege-tation cover

h humic substrate humic and wet substrate in beechwoods, covered with dead leaves

L lowland stream permanent flow, slow-running,muddy substrate, turbulent water

i inundated land agricultural fields and meadowstemporarily inundated in earlyspringtime

p puddle temporary shallow puddles for wa-tering cattle, muddy substrate, tur-bulent water

w well small natural water source of per-manent flow

wg wet grass tall wet grassland

ridibunda, Emys orbicularis, Mauremys rivu-lata) and 10 taxa of lizards and terrestrialtortoises (Testudo graeca, Testudo hermanni,Lacerta viridis/trilineata, Lacerta praticola,Ophisops elegans, Podarcis erhardi, Podarcismuralis, Podarcis taurica, Ophisaurus apodus,Ablepharus kitaibelii) (477 individuals). Fivespecies (B. variegata, E. orbicularis, M. rivu-lata, T. graeca and T. hermanni) are strictlyprotected by the European legislation (Directive92/43, Annex II).

Semi-aquatic herpetofauna

Diversity. Half of the sites sampled had no semi-aquatic species due to the absence of wet habi-tats (table 1). The most important site for theconservation of the semi-aquatic herpetofaunain the study area was the rural mosaic A2b, sup-porting six species, out of which two are strictlyprotected: B. variegata and E. orbicularis (ta-ble 1). It combined a diversity of wet habitatssuch as a brook, inundated land, wet grassesnear the field borders, and ditches and puddlesfor irrigation. The second most important sitewas the mosaic site M2, including wet habi-tats such as a brook, a wet grassland grazed

on a periodical basis and a puddle for water-ing livestock. It supported five species includingthe protected B. variegata. The riparian habi-tats (F9, F10) and the agricultural fields con-taining puddles and ditches (A1a, A1b, A2a)were also quite species rich (table 1). Withinthe study area, brooks were the most suitablehabitats for semi-aquatic taxa supporting exclu-sively the three protected species (table 3). In-undated land and lowland streams were also twoquite important habitats, supporting four breed-ing species (table 3).

Ecological structure. The sites sampled wereprojected as points along the first two orthogo-nal axes of Principal Coordinate Analysis withcorrected eigenvalues, which explained 74%of the data set variability; the ellipses corre-sponded to the clusters distinguished by Ward’sclustering procedure (fig. 2). The type of wethabitats (aquatic or wet) and their substrate type(rocky or muddy substrate) regulated the dis-tribution of semi-aquatic herpetofauna in thestudy area. The first cluster grouped togethersites with ditches, puddles and lowland streams,where common amphibian species were re-corded such as Bufo bufo, Bufo viridis andRana ridibunda. The second cluster groupedsites that contained among others wet grasses,the favourite habitat of Hyla arborea (tables 1,2). The third cluster included all sites contain-ing brooks, where B. variegata, E. orbicularisand M. rivulata were encountered, whereas twomore riparian sites with brooks (F9a, b) wereset apart (fourth cluster), because they containedonly terrapins. The fifth cluster consisted oftwo woodland sites (F6, F1a), where Rana dal-matina was the only species; it was recorded inwet grassy patches (table 1). Finally, a beechwood site with humic substrate (F1b) was dis-tinguished, as Salamandra salamandra was ex-clusively recorded there.

Terrestrial herpetofauna

Diversity. The most important habitat for theconservation of terrestrial herpetofauna werethe Quercus pubescens oak woods with ther-

Herpetofauna diversity and conservation 523

Table 3. Wet habitats where semi-aquatic herpetofauna species breed (b) or are present (p) (for habitat description, seetable 2).

Wet habitatsbrook ditch

humic inundated lowlandpuddle well

wet Total

Species substrate land steam grass

Bombina variegata b 1Bufo bufo b b b b 4Bufo viridis b b b b 4Hyla arborea p b b p 4Rana dalmatina b p 2Rana ridibunda b b b b b b 6Salamandra salamandra p p 2Triturus vulgaris p 1Emys orbicularis p 1Mauremys rivulata p 1

Total 6 3 2 4 4 4 1 2

Figure 2. Semi-aquatic herpetofauna: Ordination of the sites using Dist. Principal Coordinate Analysis. The ellipses indicatethe clusters produced by the Ward’s clustering procedure.

524 V. Kati et al.

mophilous undergrowth (F4), which supportedfive lizard species and the two protected tor-toise species – T. graeca and T. hermanni. Thesesemi-open oak woods combined a variety ofreptile microhabitats, such as shrubs, bare soil,grasses, dead oak leaves and stony patches (ta-ble 1). Heaths (H) also constituted importanthabitats for the terrestrial herpetofauna, harbor-ing four lizard species and the two protected tor-toise species. Five species were also recorded inthe semi-open oak wood site F3a and in the mo-saic site M2 (table 1). All the above species-richsites were located in the buffer zone of the Na-tional Park.

Ecological structure. The first cluster groupedtogether all the poor sites with one or twospecies regardless of their environmental char-acteristics; the second cluster grouped all sitesof open or semi-open character with dry patchesof bare soil, and the third cluster groupedseveral shady woodland sites and the sitesof humid grasslands (fig. 3, table 1). Lac-erta viridis/trilineata, Testudo graeca and Able-pharus kitaibelii were the three commonestspecies in the study area, characterizing the first,second and third cluster respectively, given theiroccurrence in all sites of the respective clusters

(table 4). No specialist species characterized thefirst cluster. A typical species of the habitats in-cluded in second cluster was Ophisops elegans,occurring exclusively there, on patches of baresoil, fully exposed to sun (90% of sites; sec-ond cluster) (table 4). Two less common specieswere exclusively encountered in the third clus-ter: Podarcis muralis was recorded in threewoodland sites (F1b, F5) and Lacerta prati-cola was recorded on the humic substrate of abeech woodland (F1b) (fig. 3, table 4). Concern-ing the ecological requirements of the species

Table 4. Number of sites where the species of terrestrial her-petofauna were recorded, according to the Ward’s clusteringprocedure (see fig. 3).

Species Cluster Cluster Cluster Sum of1 2 3 sites

Ablepharus kitaibelii 0 2 11 13Lacerta praticola 0 0 1 1Lacerta viridis/trilineata 13 9 10 32Ophisaurus apodus 1 3 1 5Ophisops elegans 0 9 0 9Podarcis erhardii 3 2 0 5Podarcis muralis 0 0 3 3Podarcis taurica 2 4 2 8Testudo graeca 1 10 5 16Testudo hermanni 5 5 2 12

N. of sites per cluster 13 10 11 34N species 6 8 8

Figure 3. Terrestrial herpetofauna. Tree of sites produced using the Ward’s clustering procedure. The species indicated arepresent to more than 90-100% of sites of the respective clusters.

Herpetofauna diversity and conservation 525

sampled, T. hermanni was quite common in thestudy area, preferring mainly the agriculturalzone (100% of agricultural sites; first cluster).We found Podarcis taurica on patches of shortgrasses (eight sites), and it was also typical ofthe sub cluster that grouped together the mostspecies rich sites (F4, H, M2). Podarcis erhardiiwas recorded on patches of stones and bare land(five sites), and Ophisaurus apodus on semi-open oak woods (five sites).

Discussion

Diversity conservation

The most important sites for semi-aquatic her-petofauna conservation in our study area werethe ones that combined a diversity of wet mi-crohabitats (i.e. sites in agricultural zone, mo-saic sites). Such habitat diversity is known to beone of the important breeding factors for pond-breeding amphibians on a larger scale (Brod-man et al., 2003) and, especially in the Mediter-ranean region, can often be attributed to hu-man activities such as field irrigation or live-stock watering. Although human modificationsof the environment have usually negative im-pacts on amphibian diversity (e.g. Kolozsvaryand Swihart, 2001; Beja and Alcazar, 2003;Brodman et al., 2003), they can also be bene-ficial when they do not involve habitat destruc-tion but rather the creation of new wet habitats.Hence, human-originated aquatic habitats, suchas puddles or ditches can improve water avail-ability during the arid season and thus favorsemi-aquatic herpetofauna. We found howeverthat anthropogenic aquatic habitats were less vi-tal for semi-aquatic herpetofauna in comparisonto natural ones, such as brooks, inundated landor lowland streams. Brooks were often reducedto pools in summertime; they were crowdedof amphibian life and sheltered also the threeprotected species against summer aridity stress.The presence of perennial streams and wetlandsis recognized as an important factor for the con-servation of semi-aquatic herpetofauna, espe-

cially in the arid climate of the Mediterraneanarea (Ficetola et al., 2004; Welsh et al., 2005),whereas inundated land is an ephemeral habitatof great value for breeding amphibian species(Helmer and Scholte, 1985; Bousbouras andIoannidis, 1997; Brodman et al., 2003).

Semi-open or open thermophilous habitatswith a well developed undergrowth of lowbushes such as oakwoods and heaths were themost important sites for the conservation of ter-restrial herpetofauna. In contrast, homogeneousand closed oak or pine woods had no particularconservation importance for terrestrial herpeto-fauna, except when possessing a more open andcomplex structure that permitted the develop-ment of bush undergrowth. However, a decreas-ing trend in the availability of open and semi-open habitats has been recorded in the broaderstudy area since the 1950s (Triantakonstantis etal., 2006), largely due to land use change forsocio-economic reasons, involving land aban-donment and decline of the free-ranged live-stock. Furthermore, oakwoods were more wide-spread in the study area before the 1950s, whentheir over-harvesting and replacement by pineplantations took place (Adamakopoulos et al.,1995). According to our results, these land usechanges may have affected negatively the di-versity of terrestrial herpetofauna, as indicatedby studies of other biological groups in theMediterranean (Farina, 1997; Preiss et al., 1997;Olsson et al., 2000; Laiolo et al., 2004). Finallyour results demonstrated the greater value of thebuffer zone for the conservation of terrestrialherpetofauna habitats in comparison with thestrictly protected zones, which were designedto protect the breeding sites of the threatenedflagship species of the National Park – the blackvulture. This holds true also for butterflies, or-thopterans and landbirds, because of the lessforested character and the greater habitat diver-sity of the buffer zone (Grill and Cleary, 2003;Kati et al., 2004, Kati and Sekercioglu, 2006).Charismatic and threatened flagship species canserve as a valuable tool to raise public aware-ness and urge rapid conservation decision, but

526 V. Kati et al.

they can also be a poor surrogate for overallbiodiversity conservation (Caro et al., 2004).Therefore, conservation managers should main-tain a sceptic attitude when creating reserves onthe basis of the ecological requirements of flag-ship species. If this is the case, they should defi-nitely broaden conservation goals to implementmanagement plans in favour of overall biodiver-sity.

Ecological structure

Our results indicated that the semi-aquatic her-petofauna classified ecologically the sites sam-pled into three main ecological types: wood-land sites with humic substrate or wet grassysubstrate, sites with brooks, and sites contain-ing lowland streams, inundated land or human-originated aquatic habitats (puddles, ditches).Species have special habitat requirements rel-evant to the degree of humidity or the type ofsubstrate of the wet habitats (e.g. Sofianidouand Kyriakopoulou, 1983; Helmer and Scholte,1985; Bousbouras and Ioannidis, 1997). Wealso found that different environmental parame-ters such as the degree of shade or the type ofsubstrate, defined the microhabitats of terres-trial herpetofauna in our study area. These para-meters describe among others (e.g. altitude, as-pect, slope) the reptile habitats in the Mediter-ranean area (Strijbosch et al., 1989; Ioannidisand Bousbouras, 1997; Nilson et al., 1999). Thepresence of adequate microhabitats is consid-ered the key factor that determines the speciesrichness of the reptile community rather thanthe landscape heterogeneity (Atauri and De Lu-cio, 2001), the degree of fragmentation (Jellineket al., 2004), or the composition of dominantplant species (Block and Morrison, 1998). Ac-cording to our results, the standard habitat typeswe used, which were defined after the compo-sition of dominant plant species and vegetationphysiognomy, failed to describe herpetofaunahabitats and hence proved inadequate manage-ment units for its conservation. Furthermore,herpetofauna species exhibited special habitat

preferences, which calls for independent man-agement actions, adapted to each species apart.

Management proposals

Conservation management since the creation ofthe Dadia reserve in 1980s naturally targetedthe birds of prey. Strict protection of the nest-ing sites of raptors, trophic enhancement of vul-tures, prohibition of woodcutting and control ofhuman access in the core areas, are only someof the measures that are successfully put intopractice in this direction. A pilot project is alsobeing carried out to monitor the population sta-tus of focal raptor species and the biotic and an-thropogenic factor affecting them (Poirazidis etal., 2002). Several recent studies have evaluatedthe current management and monitoring planfor its efficiency to conserve other focal taxasuch as orchids, invertebrates or landbirds (e.g.Kati et al., 2000, 2004, 2006; Grill and Cleary,2003). Herpetofauna is a biodiversity compo-nent that should be integrated per se in the man-agement and monitoring scheme of the NationalPark, with a special focus on the five protectedspecies. National parks have a great role inmaintaining the diversity of life forms, includ-ing amphibians and reptiles (Tuberville et al.,2005) and they should perceived in such broadcontext. Our research proposed a rapid method-ological protocol to be implemented for mon-itoring purposes. Besides, herpetofaunal mon-itoring and management would strengthen theconservation of birds of prey, given the knownvalue of reptiles as major food source for sev-eral raptor species (Strijbosch et al., 1989;Bakaloudis et al., 1998; Capper, 1998).

In the applied context, our results indicatethat the National Park authorities should con-serve the brooks of the study area as a priorityhabitat for the protected semi-aquatic herpeto-fauna species as well as the periodically floodedland, by preventing drainage works and agricul-tural intensification (Beja and Alcazar, 2003).According to our results, the creation of artifi-cial small dams in the core areas that have re-cently taken place in the frame of a LIFE project

Herpetofauna diversity and conservation 527

(WWF Greece, 2006) can be only beneficial forsemi-aquatic herpetofauna. These dams werecreated to increase amphibian species popula-tions, as a food resource of lesser spotted ea-gle (Aquila pomarina), prohibiting also the in-troduction of fish or other amphibian preda-tors there. These measures will improve wa-ter availability and will induce the creation ofnew aquatic habitats, supporting semi-aquaticspecies. Our findings also indicate that forestmanagement should target the maintenance ofthe open forest structure with low bush under-growth as well as heaths, to favour the diver-sity of terrestrial herpetofauna. This conclusionis in general consistent with the managementplan of the National Park. The latter proposes tomaintain the open wood structure and the for-est openings of the core areas and of the bufferzone, through selective woodcutting, livestockgrazing and reintroduction of large herbivores,in order to maintain the hunting biotopes forraptors (Adamakopoulos et al., 1995).

Acknowledgements. The first author expresses her thank-fulness to Bodossakis Foundation and to A. Onassis Foun-dation for supporting this research in the context of a Ph.D.scholarship for biodiversity issues.

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Received: January 24, 2007. Accepted: May 6, 2007.