Age and size of hollow oaks and their associated lichen flora and beetle fauna




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Final thesis


Age and size of hollow oaks and their associated lichen flora and beetle fauna
Niclas Berg
LiTH-IFM- Ex--05/1605--S


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Avdelning, Institution

Division, Department


Avdelningen för biologi

Institutionen för Fysik och Mätteknik







Datum

Date


06 06 08






Språk

Language






Rapporttyp

Report category







ISB

LITH-IFM-Ex--05/1605--SE


Svenska/Swedish
X Engelska/English




Licentiatavhand-ling

X Examensarbete







IS

LiU-Biol-Ex-563






C-uppsats

X D-uppsats







Serietitel och serienummer

Title of series, numrering -----




ISSN







Övrig rapport

____





Handledare: Karl-Olof Bergman

Ort: Linköping
















Titel /Title: Age and size of hollow oaks and their associated lichen flora and beetle fauna

Författare /Author Niclas Berg





Sammanfattning/ Abstract:

In Sweden the tree with most associated species is the oak (Quercus robur). More than 200 red-listed beetle species have been found in oaks. For conservational purposes it is important to understand the succession of associated species and at what age the oaks become suitable for the more rare species. The age of 77 hollow oaks in the oak landscape south of Linköping, Sweden was determined with tree ring based methods. In 1994, saproxylic beetles were trapped in window- and pitfall traps placed in the trees. The beetle data was analysed in relation to age and hollow stage. No significant differences in beetle species richness were found between older and younger hollow oaks, or between the hollow stages. On younger oaks, the correlation between age and increasing diameter and depth of bark crevices was good. In older oaks the deviation was greater. Bark crevice depth was a slightly better indicator of age than was diameter. The mean age of the hollow oaks in this study was 327 years. There were no significant differences between the hollow stages; the mean age was about the same for all hollow stages. Out of five studied lichen species (Chaenotheca phaecephala, Cliostomum corrugatum, Calicium adspersum, Schismatomma decolorans and Sclerophora coniophaea) all, except Ch. phaecephala, had higher frequencies in oaks >300 years old. Two species occurred in higher frequencies in oaks with bark crevices >50 mm (Sch. decolorans and Scl. coniophaea).









Nyckelord/ Keywords: Quercus robur, tree age, hollows, beetles, lichens, growth rate

1. Abstract 4

2. Introduction 4

2.1 Aims of the study 6

3. Materials and methods 6

3.1 Study areas 6

3.2 Determination of oak age 7

3.3 Tree specific parameters and lichen frequencies 9

3.4 Survey methods 9

3.5 Analyses 10

3.5.1 PCA & RDA 10

3.5.2 Other statistics 11

4. Results 11

4.1 Tree age 11

4.2 Age and size relationships 11

4. 3 Occurrence of lichens 13

4.4 Growth rate 15

4.4.1 Stone coverage and moisture 15

4.4.2 Openness 16

4.5 Age and hollow stage 17

4.6 Beetle statistics 18

4.6.1 Osmoderma eremita 18

4.6.2 Species richness 19

4.6.3 Red-list score 20

4.6.4 PCA and RDA 22

5. Discussion 22

5.1 Age determination of hollow oaks 22

5.2 Growth rate 24

5.3 Lichens 25

5.4 Age and hollow stage 26

5.5 Species richness and Osmoderma eremita frequencies 27

6. Acknowledgements 28

7. References 29



Appendix 1………………………………………………………………..30



1. Abstract


In Sweden the tree with most associated species is the oak (Quercus robur). More than 200 red-listed beetle species have been found in oaks. For conservational purposes it is important to understand the succession of associated species and at what age the oaks become suitable for the more rare species. The age of 77 hollow oaks in the oak landscape south of Linköping, Sweden was determined with tree ring based methods. In 1994, saproxylic beetles were trapped in window- and pitfall traps placed in the trees. The beetle data was analysed in relation to age and hollow stage. No significant differences in beetle species richness were found between older and younger hollow oaks, or between the hollow stages. On younger oaks, the correlation between age and increasing diameter and depth of bark crevices was good. In older oaks the deviation was greater. Bark crevice depth was a slightly better indicator of age than was diameter. The mean age of the hollow oaks in this study was 327 years. There were no significant differences between the hollow stages; the mean age was about the same for all hollow stages. Out of five studied lichen species (Chaenotheca phaecephala, Cliostomum corrugatum, Calicium adspersum, Schismatomma decolorans and Sclerophora coniophaea) all, except Ch. phaecephala, had higher frequencies in oaks >300 years old. Two species occurred in higher frequencies in oaks with bark crevices >50 mm (Sch. decolorans and Scl. coniophaea).
Keywords: Quercus robur, tree age, hollows, beetles, lichens, growth rate
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