Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt Lehrstuhl für Terrestrische Ökologie Evaluation of an integrative strategy in forests: does deadwood enrichment work and increase biodiversity? Inken Susanne Dörfler Vollständiger Abdruck der von der Fakultät Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt der Technischen Universität München zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften genehmigten Dissertation. Vorsitzender: Prof. Dr. Dr. h.c. Hans Pretzsch Prüfende/-r der Dissertation: 1. Prof. Dr. Wolfgang W. Weisser 2. Prof. Dr. Jörg Müller (Ludwig-Maximilians-Universität München) 3. Prof. Dr. Heike Feldhaar (Universität Bayreuth) Die Dissertation wurde am 22.08.2017 bei der Technischen Universität München eingereicht und durch die Fakultät Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt am 25.10.2017 angenommen. It all came together then, you see—all the various isolated bits—and made a coherent pattern. Miss Marple, Agatha Christie 1950, A murder is announced Acknowledgements I want to express my gratitude towards my supervisor Prof. Wolfgang W. Weisser who enabled the project for me, even in difficult times. I also want to thank Martin M. Gossner, Jörg Müller and Sebastian Seibold who did a great job in supporting me and answering many questions. I found many great colleagues - today also friends, at the Chair of Terrestrial Ecology, which was the best thing that could happen: Thanks for all the coffee breaks, the expired beer and all those conversations. Especially Brigitte Grimm is a treasure, making many things possible that I thought to be lost. However, also outside of our chair many people offered help that was priceless. This included Markus Blaschke and Heinz Bussler who did a great job as experts. It also includes the whole staff in the forestry department Ebrach, especially Uli Mergner with his great commitment towards sustainable forestry and its scientific evaluation. Besides that, there were a lot of people who have done so many things that may seem small in detail but that were invaluable for accomplishing the project. This includes, the wonderful people from the field station in Fabrikschleichach, from the Bavarian Forest National Park and from the University of Toronto Scarborough, especially Marc Cadotte and possibly many more whom I’ve unfortunately missed to mention. This project was funded by the Bavarian Ministry of Food, Agriculture and Forestry (Bayerisches Staatsministerium für Ernährung, Landwirtschaft und Forsten). I want to expresses my gratitude to the advisory board of this project, especially Reinhardt Neft, MR Dr. Stefan Nüßlein, MR Günter Biermayer, Florian Zormaier and Erich Leihs, who were willing to let us realize this project. Content Zusammenfassung ...................................................................................................................... v Summary .................................................................................................................................. vii 1. Introduction ............................................................................................................................ 1 1.1 Global threats to biodiversity ........................................................................................... 1 1.1.1 Conservation agreements in Germany ...................................................................... 1 1.1.2 Improvement of current conservation actions ........................................................... 2 1.2 Biodiversity and threat of saproxylic species ................................................................... 3 1.2.1 Properties of saproxylics’ habitat .............................................................................. 3 1.2.2 Influences of forest management on saproxylics’ habitat and their biodiversity ...... 5 1.3 Integrative management for deadwood enrichment ......................................................... 7 1.3.1 Passive approaches .................................................................................................... 7 1.3.2 Active approaches ..................................................................................................... 8 1.4 Integrative conservation in German beech forests ......................................................... 11 1.5 Single chapters of the manuscript .................................................................................. 14 A) Evaluation of the changes in deadwood amounts and their drivers ............................ 14 B) Description of biodiversity before and after the implementation of the strategy ........ 15 C) Relation between changes in biodiversity and deadwood enrichment ........................ 16 D) Relationship of assembly mechanisms and deadwood enrichment ............................ 17 1.6 Specific aims and Questions .......................................................................................... 18 2. Methods ................................................................................................................................ 21 2.1 Research Area ................................................................................................................ 21 2.1.1 Climate and soil conditions ..................................................................................... 21 2.1.2 Bavarian state forest company and department Ebrach .......................................... 23 2.2 Data ................................................................................................................................ 24 2.2.1 Regular forest inventory .......................................................................................... 25 2.2.2 Additional forest inventory ..................................................................................... 27 2.2.3 Species records ........................................................................................................ 30 2.3 Statistics ......................................................................................................................... 32 2.3.1 General statistics ..................................................................................................... 32 2.3.2 Chapter A) Evaluation of the changes in deadwood amounts and their drivers ..... 32 i 2.3.3 Chapter B) Description of biodiversity before and after the implementation of the strategy ............................................................................................................................. 34 2.3.4 Chapter C) Relation between changes in biodiversity and deadwood enrichment ........................................................................................................................ 35 2.3.5 Chapter D) Relationship of assembly mechanisms and deadwood enrichment ...... 36 3. Results .................................................................................................................................. 41 3.1 Chapter A) Evaluation of the changes in deadwood amounts and their drivers ............ 41 3.1.1 Description of deadwood amounts before and after the implementation of the deadwood enrichment strategy ......................................................................................... 41 3.1.2 Deadwood amounts in different areas ..................................................................... 41 3.1.3 Living stand parameters before and after the implementation of the deadwood enrichment strategy .......................................................................................................... 44 3.1.4 Change in Deadwood profile ................................................................................... 51 3.1.5 Habitat trees ............................................................................................................. 52 3.2 Chapter B) Description of biodiversity before and after the implementation of the strategy ................................................................................................................................. 53 3.2.1 Beetles ..................................................................................................................... 53 3.2.2 Fungi ........................................................................................................................ 54 3.2.3 Birds ........................................................................................................................ 55 3.2.4 Plants ....................................................................................................................... 55 3.2.5 True bugs ................................................................................................................. 55 3.2.6 Multidiversity index ................................................................................................ 56 3.3 Chapter C) Relation between changes in biodiversity and deadwood enrichment ........ 59 3.3.1 Environmental variables .......................................................................................... 59 3.3.2 Drivers of biodiversity change ................................................................................ 59 3.4 Chapter D) Relationship of assembly mechanisms and deadwood enrichment ............. 63 3.4.1 Description and phylogenetic signal of traits .......................................................... 63 3.4.2 Optimal a-value ......................................................................................................