PALOMA TORROBA 1, Mª Pilar Zaldívar García2, Mª Belén Fernández-Santos3 & Carolina Martínez-Ruiz1,4

1Area of Ecology, Department of Agro-Forestry Sciences, University of Valladolid, Spain. E-mail: paloma.torroba@gmail.com2Area of Botany, Department of Agro-Forestry Sciences, University of Valladolid, Spain3Area of Ecology, Faculty of Biological Sciences, University of Salamanca, Spain 4Sustainable Forest Management Research Institute UVa-INIA (Spain)

12th EEF Congress. Avila 2011

•Physical and biotic changes

•Spatial regeneration pattern

•Variation of resources

Characterize the natural regeneration of sessile oak (Quercus petraea) in three microhabitats present in the study area

Characterize the natural regeneration of sessile oak (Quercus petraea) in three microhabitats present in the study area

Guardo

Study area

Opencast coal mine reclaimed in 1990Opencast coal mine reclaimed in 1990

Hydric stress

Dry season

Low water holding capacity

Hydric stress

Dry season

Low water holding capacity

B - the adjacent oak forest edge

M1 - the restored mine area close to the forest

M2 - the restored mine area away from forest

B - the adjacent oak forest edge

M1 - the restored mine area close to the forest

M2 - the restored mine area away from forest

Soil characteristics

Forest influence

Seed arrival

M1 M2B

12 m12 m 6 m6 m 8 m8 m

5.7 % shrub cover/plot

5.7 % shrub cover/plot 70.0 % s.c./plot70.0 % s.c./plot 61.0 % s.c./plot61.0 % s.c./plot

Environmental gradient

BM1 M2

Seedling density (ind./m2)

Maximum alive height (<50 cm)

Diameter (mm)

Nº of total and dead branches

Age range (1, 2-3, >3 years old)

Presence of moss

% shrub cover/plot

Angle of contact

% shrub cover around seedlings

60 plots, 2 x 2 m2

10 20 30 40 50 60 70 80 90 100

% shrub cover around seedlings

0%

10%

20%

30%

40%

50%

% s

eed

lin

gs

0

4

8

12

16

20

24

28

32

nº

seed

lin

gs

1020

3040

5060

7080

90100

% shrub cover around seedlings

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

% s

eed

lin

gs

050100150200250300350400450500550600650

nº

seed

lin

gs

1020

3040

5060

7080

90100

% shrub cover around seedlings

0%

4%

8%

12%

16%

20%

24%

28%

32%

% s

eed

lin

gs

0

10

20

30

40

50

60

70

80

nº

seed

lin

gs

% s

hru

b c

ove

r a

rou

nd

see

dli

ng

s%

sh

rub

co

ver

aro

un

d s

eed

lin

gs

53% 80%

χ2=256.26; gl=18; p<0.0001; Chi-square test

97%

Shrub protection B M1 M2 Kruskal-Wallis test

Average angle (º) 3.3 147.7 241.7 H=996.1; gl=2; p<0.0001

Average% shrub cover 11.7 72.9 83.1 H=701.0; gl=2; p<0.0001

3060

90120

150180

210240

270300

330360

angle of contact (º)

0%

15%

30%

45%

60%

75%

90%%

see

dlin

gs

0

200

400

600

800

1000

1200

nº

see

dlin

gs

3060

90120

150180

210240

270300

330360

angle of contact (º)

0%

4%

8%

12%

16%

20%

24%

28%

% s

ee

dli

ng

s

0

10

20

30

40

50

60

70

nº

se

ed

lin

gs

3060

90120

150180

210240

270300

330360

angle of contact (º)

0%

5%

10%

15%

20%

25%

30%

35%

40%

% s

ee

dli

ng

s

0

2

4

6

8

10

12

14

16

18

20

22

24

nº

se

ed

lin

gs

49% 43%99%

χ2=232.90; gl=22; p<0.0001; Chi-square test

B M1 M2

B M1 M2

An

gle

of

con

tact

An

gle

of

con

tact

Shrub protectionShrub protection

B M1 M2

m icrohabitat

0

2

4

6

8

10

12

14

16

18

20

22

de

ns

ity

(in

d/m

2 )

Seedling characteristicsSeedling characteristics

16.3 ind./m2

3.1 ind./m2

0.7 ind./m2

Density (ind./m2)Density (ind./m2)

a

b

c

B

M2

Wald st.=256.97; gl=2; p<0.0001; ANOVA based on Poisson distribution

S.E. 20)(n X

B M 1 M 2

m icrohabitat

0,15

0,20

0,25

0,30

0,35

0,40

0,45

0,50

0,55

0,60

1-y

ea

r-o

ld s

ee

dlin

g d

en

sit

y (

ind

./m2 )

1 year old 2-3 years old >3 years oldB M 1 M 2

microhabitat

0

20

40

60

80

100

% s

eed

ling

s

density

youth

regeneration=

Environmental conditions get worse

Lower survival

Age structureAge structure

χ2=65.47; gl=4; p<0.0001; Chi-square testF(2, 57) = 0.47; p = 0.629; ANOVA

1-year-old seedling density1-year-old seedling densityB (n=1307 ind.)M1 (n=248)M2 (n=60) B (n=20 plots)

M1 (n= 20)M2 (n=20)

B M 1 M 2m icrohabitat

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

dia

met

er (

mm

)

B M 1 M 2m icrohabitat

0

2

4

6

8

10

12

14

16

18

hei

gh

t (c

m)

a a

b

ab

a

b

B: r=0.60; M1: r=0.79; M2: r=0.66 (p<0.0001)

Height (cm)Height (cm)

Light level

Forest influenceM1: Higher size and Pearson´s coefficient (r)

H=37.07; gl=2; p<0.0001; Kruskal-Wallis test

H=7.98; gl=2; p=0.0185; Kruskal-Wallis test

Diameter (mm)Diameter (mm)

± S.E.

B (n=1307)M1 (n=248)M2 (n=60)

X

B M 1 M 2

m icrohabitat

0

10

20

30

40

50

% d

ea

d b

ran

ch

es

B M1 M2

m icrohabitat

0

1

2

3

4

5

nº

of

tota

l b

ran

ch

es

a

c

b% damaged seedlings

6% 6% 1 year-old seedling (n=84 ind.)

77.1% 77.1% seedling in the whole sample (n=1345 ind.)

% damaged seedlings

6% 6% 1 year-old seedling (n=84 ind.)

77.1% 77.1% seedling in the whole sample (n=1345 ind.)

a

b

a

Number of total branchesNumber of total branches

M2:YoungerMore shrub protection

B:OlderLess shrub protection

H=16.34; gl=2; p=0.0003; Kruskal-Wallis test

H=40.99; gl=2; p<0.0001; Kruskal-Wallis test

% dead branches% dead branches

± S.E.

B (n=1307 ind.)M1 (n=248)M2 (n=60)

X

± S.E.

B (n=1307 ind.)M1 (n=248)M2 (n=60)

X

Herbivory damageHerbivory damage

M2:YoungerMore shrub protection

B:OlderLess shrub protection

Less density

More densityB M1 M2

m icrohabitat

0

2

4

6

8

10

12

14

16

18

20

22d

en

sit

y (

ind

/m2 )

a

bc

B M 1 M 2

microhabitat

0

10

20

30

40

50

60

70

% p

rese

nce

of

mo

ss

Environmental conditions:

Hydric stress

Environmental conditions:

Hydric stress

a

a

b

Moss presence around seedlings

increases

Moss presence around seedlings

increases

% moss presence per plot% moss presence per plot

(n=20) ± S.E.XH=17.82; gl=2; p=0.0001; Kruskal-Wallis test

Nº of seedlings surrounded by moss in each microhabitat considered.

Aspect influence (North aspect, South aspect)Aspect influence (North aspect, South aspect)

South aspect

North aspect

South aspect North aspect

N

Sou th asp e ct No rth asp e ct

asp e ct

0

5

10

15

20

25

30

35

40

45d

en

sit

y (

ind

/m2

)

South aspect N orth aspect

aspect

0,0

0,5

1,0

1,5

2,0

2,5

3,0

dia

me

ter

(mm

)

South aspect North aspect

aspect

0

2

4

6

8

10

12

14

hei

gh

t (c

m)

a

b

Density (ind./m2)Density (ind./m2)

Height (cm)Height (cm)

a

b

33.3 ind./m2

9.1 ind./m2

U=6.00; gl= p=0.003; Mann-Whitney U test

t=-12.70; gl=1303; p<0.0001 t=-7.51; gl=1304; p<0.0001

a

b

9.2 cm12.4 cm 2.60 mm3.04 mm

± S.E.North aspect (n=14)South aspect (n=6)

X

Diameter (mm)Diameter (mm)

North aspect (n=509 ind.)

South aspect (n=798)

t-Student test

± S.E.X

North aspect:•Lower density and size

South aspect:•Higher survival•Higher size

north aspect south aspect

aspect

0,0

0,1

0,2

0,3

0,4

0,5

0,6

1-ye

ar-o

ld s

eed

lin

g d

ensi

ty (

ind

./m

2 )

1-year-old seedling density (ind./m2)1-year-old seedling density (ind./m2)

North aspect:•Lower density and size

South aspect:•Higher survival•Higher size

U=19.5; p=0.053; Mann-Whitney U test

± S.E.North aspect (n=14)South aspect (n=6)

X

1. Seedling survival is strongly related with the environmental gradient (density, age)

2. Hydric stress seems to affect seedling survival more than herbivory damage

3. Light level could explain differences in seedling size among microhabitats, while age and shrub protection may influence branch mortality

4. In forest microhabitat, aspect is a parameter which influences oak regeneration (ecological requirements)