Carbon and Nutrient Cycles Depending on Climate and Land Use Along the Elevation Gradient of Mount Kilimanjaro
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Carbon and nutrient cycles depending on climate and land use along the elevation gradient of Mount Kilimanjaro Dissertation zur Erlangung des mathematisch-naturwissenschaflichen Doktorgrades “Doctor rerum naturalium“ Der Georg-August-Universität Göttingen Im Promotionsprogramm Biodiversität and Ökologie der Georg-August University School of Science (GAUSS) vorgelegt von Joscha Nico Becker aus Berlin Göttingen, Mai 2017 Betreuungsausschuss Prof. Dr. Yakov Kuzyakov, Ökopedologie der gemäßigten Zonen & Agrarpedologie, Georg-August-Universität Göttingen Prof. Dr. Bernd Huwe, Bodenphysik, Universität Bayreuth Dr. Dietrich Hertel, Pflanzenökologie und Ökosystemforschung, Georg-August- Universität Göttingen Mitglieder der Prüfungskommission Referent/in: Prof. Dr. Michaela Dippold, Biogeochemie der Agrarökosysteme, Georg-August-Universität Göttingen 1. Korreferent/in: Prof. Dr. Daniela Sauer, Physische Geographie, Georg- August-Universität Göttingen 2. Korreferent/in: Prof. Dr. Sandra Spielvogel, Bodenkunde, Universität Bern Weitere Mitglieder der Prüfungskommission: Prof. Dr. Andrea Carminati, Bodenhydrologie, Georg-August- Universität Göttingen PD Dr. Dirk Gansert, Zentrum für Biodiversität und Nachhaltige Landnutzung, Georg-August-Universität Göttingen Prof. Dr. Dirk Hölscher, Waldbau und Waldökologie der Tropen, Georg-August-Universität Göttingen Prof. Dr. Christoph Leuschner, Pflanzenökologie und Ökosystemforschung, Georg-August-Universität Göttingen Tag der mündlichen Prüfung: 06.07.2017 Table of Contents I Table of Contents Table of Contents ..................................................................................................................................... i List of Tables ............................................................................................................................................ iv List of Figures ........................................................................................................................................... vi Summary ................................................................................................................................................. xi 1 Extended Summary ......................................................................................................................... 1 1.1 Introduction ............................................................................................................................. 1 1.1.1 Background and Motivation ............................................................................................ 1 1.1.2 Climatic control of ecosystem cycles ............................................................................... 2 1.1.3 Land-Use Change at Mt. Kilimanjaro ............................................................................... 3 1.1.4 Spatial interaction of above and belowground processes .............................................. 4 1.1.5 Objectives ........................................................................................................................ 6 1.2 Material and Methods ............................................................................................................. 7 1.2.1 Study area ........................................................................................................................ 7 1.2.2 Research approaches .................................................................................................... 10 1.3 Results and Discussion .......................................................................................................... 14 1.3.1 Overview of Main Results .............................................................................................. 14 1.3.2 Effects of elevation and land use on C and nutrient cycling ......................................... 16 1.3.3 Effects of elevation on soil microbial communities and organic matter composition .. 19 1.3.4 Spatial interaction of above and belowground processes ............................................ 22 1.4 Conclusions ............................................................................................................................ 26 1.5 Contribution to studies.......................................................................................................... 28 1.6 References ............................................................................................................................. 30 2 Publications and Manuscripts ....................................................................................................... 42 2.1 Study 1: Annual litterfall dynamics and nutrient deposition depending on elevation and land use at Mt. Kilimanjaro ............................................................................................................... 42 Abstract ......................................................................................................................................... 43 2.1.1 Introduction ................................................................................................................... 44 2.1.2 Methods ........................................................................................................................ 45 2.1.3 Results ........................................................................................................................... 48 2.1.4 Discussion ...................................................................................................................... 51 2.1.5 Conclusions .................................................................................................................... 55 2.1.6 Acknowledgements ....................................................................................................... 55 Table of Contents II 2.1.7 References ..................................................................................................................... 56 2.1.8 Appendix A .................................................................................................................... 62 2.2 Study 2: Teatime on Mount Kilimanjaro: Seasonal variation in standardized litter decomposition and effects of elevation and land use ...................................................................... 63 2.2.1 Abstract ......................................................................................................................... 64 2.2.2 Introduction ................................................................................................................... 65 2.2.3 Methods ........................................................................................................................ 66 2.2.4 Results ........................................................................................................................... 69 2.2.5 Discussion ...................................................................................................................... 72 2.2.6 Conclusions .................................................................................................................... 75 2.2.7 Acknowledgements ....................................................................................................... 76 2.2.8 References ..................................................................................................................... 76 2.2.9 Supporting tables .......................................................................................................... 82 2.3 Study 3: Climatic and decomposer community effects of leaf-litter decomposition along the elevation gradient of Mt. Kilimanjaro ......................................................................................... 83 2.3.1 Abstract ......................................................................................................................... 84 2.3.2 Introduction ................................................................................................................... 85 2.3.3 Methods ........................................................................................................................ 86 2.3.4 Results and Discussion................................................................................................... 86 2.3.5 Conclusions .................................................................................................................... 89 2.3.6 Acknowledgements ....................................................................................................... 90 2.3.7 References ..................................................................................................................... 90 2.4 Study 4: Soil microbial community structure in forest soils along the elevation gradient of Mount Kilimanjaro ............................................................................................................................. 93 2.4.1 Abstract ......................................................................................................................... 94 2.4.2 Introduction ................................................................................................................... 95 2.4.3 Material and methods ................................................................................................... 96 2.4.4 Results ........................................................................................................................... 98 2.4.5 Discussion ...................................................................................................................