Effects of afforestation on species richness of plants and animals in Iceland

Asrun Elmarsdottir1, Bjarni D. Sigurdsson2, Bjarni E. Gudleifsson2, Brynja Hrafnkelsdottir3, Arne Fjellberg4, Gudmundur Halldorsson5, Gudridur G. Eyjolfsdottir1, Gudmundur A. Gudmundsson1,

Kristinn H. Skarphedinsson1, Erling Olafsson1, Maria Ingimarsdóttir1,Olafur K. Nielsen1 and Borgthor Magnusson1

1) Icelandic Institute of Natural History 2) Agricultural University of Iceland 3) Icelandic Forest Research, Mogilsa 4) Entomological Research, Tjöme, Norway; 5) Icelandic Soil Conservation Service.

Corresponding author: bjarni.sigurdsson@lbhi.is

Edda Sigurdis OddsdottirIcelandic Forest Research, Mogilsa

Afforestation may have severalconsequences:

• Changes soil conditions• Change ground vegetation

– Original vegetation replaced by woodlandvegetation

– Reduces plant species diversity• Changes invertebrate fauna

– Depented on tree species used• Dispersal of introduced species• New pathogens and pests

Peterken 2001, Engelmark 2001,Cannell 1999

What is biodiversity?

• Species richness; the number of species in a community, plot or sample

• Species eveness: the distribution of individuals among the species

• Species diversity; a good measure of diversity should take into account boththe number of species and theevenness of individuals in the variousspecies

Until now, most biodiversity studies have focused on one or few functional groups:

•Vascular plants•Birds•Beetles

Are those representative for the whole ecosytem???What about the rest???

Why Iceland??

• Limited native flora and fauna • Only three native tree species,

– Birch (Betula pubescens) the only forest forming• Very low forest cover (1.5%)• Large scale afforestation programs

– Use of introduced conifers (larch, spruce, pine)• Good opportunity to study the effects of

afforestation on species richness

The goal

• Study the the influence of afforestation on the ecosystem

• Describe changes in biodiversity– how communities of flora, fungi, arthropods, and

birds change when open land is converted to forest• Are there differences between exotic and native

forest types?

More information..

• Posters– Effects of afforestation by exotic conifers

and native birch on ground vegetation composition in Iceland

– The effects of afforestation on Collemboladensity and species number

• Talk– Effects of afforestation on carbon stocks

and fluxes of previously grazed heathlands in Iceland

What are the effects of afforestation on species richness ?

Decreasing Steady Increasing

or or

What are changes in species richness?Σ (vascular plants, non-vascular plants, fungi, arthropods, birds,)

Study sites

Two study areas in Iceland, Fljótsdalshérað (East Iceland) andSkorradalur (West Iceland)Vegetation types

• grazed heathlands• native forests (Betula pubescens) • exotic forests (Larix sibirica, Picea sitchensis, Pinus contorta)

Conducted in chronosequences for each forest type

19651990 1985 1952

7-10 m4-6 m

13-16 m

2-4 m

Study sites

• Continuous forests larger than 300 ha• Each stand larger than 3 ha• Five plots in each stand• Replicated measurements conducted

on plots– Except birds

Skorradalur- West Iceland– Heathland– Birch forests (Betula pubescens)– Spruce forests (Picea sitchensis)

• S-1, planted 1995; • S-2, planted 1970; • S-3, planted 1960-1961, unmanaged• S-4, planted in 1961, managed

– Pine forests• P-1 planted in 1990• P-2 planted in 1965-68• P-3 planted in 1958-59

H-1 Heathland

S-1 Spruce (1995)

S-3 Spruce (1960-61)

Birch

Flora

2 1 2 2 1 2

28 239 14 13 16

59 67

34 23 3240

0 1

11

10

Heat

h

Spru

ce_1

Spru

ce_2

Spru

ce_3

Spru

ce 4

Nativ

e birc

hLicens Moss Vascular pl Bushes

‐ 35%

‐47%

Results

Breeding birds

129 9 9 9

7

Heat

h

Spru

ce_1

Spru

ce_2

Spru

ce_3

Spru

ce 4

Nativ

e birc

h

‐ 42%‐ 25%

ResultsSurface insects (Beetles, spiders, flies, etc.)

85101

71 82 84 90

Heath

Spruce_1

Spruce_2

Spruce_3

Spruce 4

Native birch

Results

Fungi

50

8

1821

15He

ath

Spru

ce_1

Spru

ce_2

Spru

ce_3

Spru

ce 4

Nativ

e birc

h

+ 420%+ 300%

Soil animals

5 4 5 4 5 5

14 14 1420 19

11

Heat

h

Spru

ce_1

Spru

ce_2

Spru

ce_3

Spru

ce 4

Nativ

e birc

h

Earthworms Collembola

+ 26%

- 16%

"Total" species richness in heathland, Sikta spruce and native birch

19 18 19 24 24 165 0 8 18 21 15

85 101 7182 84 90

5967

3423 32 40

129

99

9 7

Heat

h

Spru

ce_1

Spru

ce_2

Spru

ce_3

Spru

ce 4

Nativ

e birc

h

Soil anim. Fungi Surface insects Flora Birds

Effects of Afforestation on Total Species Richness

0

50

100

150

200

250

300

Pine

_3

Spruce_2

Birch_

W2

Larch_

4    

Pine

_2    

Spruce_3

Larch_

5

Birch_

Eold

Spruce 4

Birch_

W3

Birch_

W1

Heath_E

Heath_W

Pine

_1

Spruce_1

Larch_

1

Larch_

3

Larch_

2

Birch_

Eyng

Num

ber of spp

#2: YoungOpen Birch and Confer 

Stands+

Less Grazing  Pressure 

#4: OlderBirch or Conifer 

+ 

Thinned or Past Thicket stage

#3: Middle‐aged dense stands

+ 

Thicket stage

#1 Start:Heathland

Conclusions

• No difference in “total” species richness of oldest age classes between conifers andbroadleaved

• Afforestation affects different functionalgroups in different ways

• It is not possible to judge the effect of afforestation on species richness based onone or few functional group(s)

• Forest management is an important factor indeterminating species richness

Thank you for your attention

Icewood-ers