Forschung & Projekte
Tree-Tree Interactions in subtropical forests (TreeDi)
Funding institute: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) and University of Chinese Academy of Sciences (UCAS)
Partners: German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Martin Luther University Halle-Wittenberg, Friedrich Schiller University Jena, Leipzig University, Dresden University of Technology, University of Göttingen, University of Chinese Academy of Sciences
Duration: 2018 - 2027
PIs in the institute: Sylvia Haider, Andreas Fichtner
Institute staff working on the project: Akhil Murali, Pablo Castro Sánchez-Bermejo
Website: https://www.idiv.de/en/treedi.html
"TreeDì - 林地 - TreeDiversity Interactions: The role of tree-tree interactions in local neighbourhoods in Chinese subtropical forests" is an International Research Training Group involving both German and Chinese institutions. TreeDì’s objective is to understand how tree-tree interactions in local neighbourhoods of varying diversity translate into the observed positive tree species richness effects on key ecosystem functions at the community scale. To do so, our work primarily focuses on BEF-China (https://bef-china.com/), a tree diversity experiment located in Xingangshan (BEF-China), in Jiangxi province, Southeast China. Specifically, the experiment is located in a subtropical region dominated by evergreen broad-leaved forests with a unique evolutionary history where certain tree lineages have radiated enormously. This area features evergreen broad-leaved forests with a distinct evolutionary history, characterized by significant radiation within certain tree lineages. With its rich diversity of woody species thriving naturally, these subtropical forests offer an unparalleled setting for delving deeper into the dynamics of woody species interactions. In the experiment, local tree species were planted in plots with different levels of diversity: seven levels of tree species richness (0, 1, 2, 4, 8, 16 and 24 tree species) combined with four levels of shrub species richness (0, 2, 4, 8 shrub species).
By bringing together experts and doctoral researchers from research institutions located in Germany and China, TreeDì creates a stimulating network of scientists. At Leuphana, researchers are engaged in various subprojects within the graduate school. Specifically, Andreas Fichtner is involved in the subproject “Spatial aboveground complementarity”, which aims to understand how tree-tree interactions drive spatial complementarity in tree crowns. Further, Pablo Castro Sánchez-Bermejo and Sylvia Haider are involved in the subproject “Complementarity through trait variation” which studies the intraspecific variation in leaf functional traits as response to tree diversity.
In 2023, all subprojects of TreeDì focused on the study of interactions between trees and shrubs and their effects on ecosystem functioning. To achieve this, we carried out a coordinated fieldwork campaign in August and September 2023. We sampled shrubs and the trees surrounding them in different plots varying in tree diversity and composition. Various measurements were conducted, including individual tree and shrub size, leaf trait assessments, evaluation of leaf herbivory and fungal infestation, soil microbial community activity analysis through soil core sampling, and terrestrial laser scanning to investigate spatial complementarity. In the specific case of the subproject “Complementarity through trait variation”, more than 6,000 leaves from trees and shrubs were collected for the assessment of morphological and chemical properties of leaves. This dataset is allowing us to understand how trees and shrubs adapt their leaf strategy to their biotic context. In the subproject “Spatial aboveground complementarity”, terrestrial and personal laser scanning techniques were used to accurately quantify the three-dimensional structure of trees, shrubs and communities. This allows us to explore how diversity-mediated structural changes translate into canopy complementarity.
©Sylvia Haider
©Sylvia Haider
DIVERSA-Teilprojekt 03: Funktionelle Trockenresistenz von Bäumen
Funding institute: The Lower Saxony Center for Climate Research and its Climate Future Labs are funded by the programme zukunft.niedersachsen of the Lower Saxony ministery of science and culture and the VolkswagenStiftung.
Partners: Leuphana University Lüneburg
Duration: 2024 – 2030
PIs in the institute: Sylvia Haider, Andreas Fichtner
Institute staff working on the project: Carolin Luisa Lidola, Luzie Emilia Glock
Website:zkfn.de/diversa/
DIVERSA subproject 03: Functional drought resistance of trees
Das Ziel besteht darin, unser Verständnis darüber zu verbessern, wie verschiedene Laubbaumarten auf Hitze und Trockenheit reagieren, um eine nachhaltige Waldbewirtschaftung angesichts des Klimawandels zu ermöglichen.
Das Verständnis darüber, wie Bäume auf die zunehmende Schwere und Häufigkeit extremer Wetterereignisse wie Dürren reagieren, ist von zentraler Bedeutung für die Vorhersage künftiger Veränderungen der Waldstruktur und -funktionen. Hierbei wird davon ausgegangen, dass hydraulische Eigenschaften eine Schlüsselrolle für die Anpassungsfähigkeit eines Baumes an ein sich veränderndes Klima spielen. Die Auswirkungen des Klimawandels können durch Waldbewirtschaftung und erhöhte Stickstoffablagerungen in der Luft weiter moduliert werden. Allerdings wissen wir noch immer nur wenig darüber, wie sich das Zusammenspiel von Waldbewirtschaftung und Stickstoffablagerungen auf die Klimasensitivität von Bäumen auswirkt. Unser Ziel ist es, die durch Hitze und Trockenheit ausgelösten Reaktionen verschiedener Laubbaumarten besser zu verstehen, um die Waldbewirtschaftung unter den Bedingungen des Klimawandels zu unterstützen.
Zu diesem Zweck messen wir vor Ort verschiedene hydraulische, morphologische und strukturelle Eigenschaften von Bäumen mit verschiedenen Methoden wie Blattspektroskopie, Embolieanfälligkeitskurven und mobilem Laserscanning. Die Auswirkungen von Hitze und Trockenheit auf das Baumwachstum werden anhand von Baumringanalysen bewertet. In einem zusätzlichen Gewächshausversuch wird die Ausprägung der Eigenschaften in einer kontrollierten Umgebung mit Trockenheit und erhöhtem Stickstoffgehalt untersucht.
©Carolin Lidola
©Carolin Lidola
BETA-FOR – ENHANCING STRUCTURAL DIVERSITY IN PRODUCTION FORESTS
Funding institute: Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)
Partners: Julius-Maximilians-University Wuerzburg, Georg-August-University Goettingen, German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Albert-Ludwigs-University Freiburg, TU Dresden, Utrecht University, University Leipzig, Black Forest National Park, University of Bayreuth, Goethe University Frankfurt am Main
Duration: 01.05.22 – 01.05.26
PIs in the institute: Andreas Fichtner, Benjamin Delory
Institute staff working on the project: Pia Bradler
Website: https://www.uni-wuerzburg.de/en/beta-for/
The BETA-FOR project aims to explore the impacts of forest homogenization on biodiversity and ecosystem functions. The decline in β-diversity due to increasing human activities has led to large-scale forest homogenization. Through experimental approaches, we aim to develop guidelines for sustainable forest management to reverse negative impacts of homogenization.
Within the research unit, we investigate the effects of an enhancement of structural complexity in forests on biodiversity and multifunctionality by comparing a treatment district with a control district. This paired forest landscape design is replicated at eleven sites in Germany (Fig. above). In each treatment district, resource availability has been altered by different combinations of light (open or closed canopy) and dead wood availability (e.g. standing dead wood, logs, stumps). Each of the nine patches in a treatment district has received a different treatment, thus increasing structural beta-complexity, which we expect to influence biodiversity and multifunctionality. Our aim is to establish a connection between β-diversity and multifunctionality and to develop recommendations for long-term forest conservation strategies.
The main objective of our subproject within the research unit is to investigate how a higher spatial heterogeneity in forest structure affects the diversity of vascular plants, terricolous bryophytes, and lichens in the forest understory across spatial scales, and how this modulates above- and belowground functioning in terms of biomass production.
In collaboration with a great team including student assistants, bachelor and master students, technical staff, our colleagues at TU Dresden and across the research unit, we successfully conducted field work in all eleven study regions. 2023 year was the first year in which vegetation surveys were conducted in all 234 patches across the eleven forest landscapes, allowing analyses of structural enhancement in treatment districts compared to control districts across all study regions. Moreover, we sampled aboveground biomass during summer and fine root samples as a measure of belowground biomass production in all patches during autumn. This allows us to link patterns in species richness to patterns in biomass production and to see how this is influenced by the structural enhancement. Additionally, we took hemispheric pictures which enables us to quantify light availability as a key resource for plants in the forest understory.
We are currently working on quantifying how the enhancement of structural beta-complexity influences the taxonomic, phylogenetic and functional diversity of vascular plants across spatial scales (alpha, beta and gamma). Our project and first preliminary results were presented at the GfÖ conference in Leizig (poster presentation) and during our BETA-FOR project workshop in October. Furthermore, several Bachelor students have successfully finished their theses within our project.
Mountain Invasion Research Network (MIREN) / RangeX
MIREN
Funding Institute: Deutsche Forschungsgemeinschaft (DFG); BiodivERsA
Partners:
MIREN: Conicet Ianigla (AR), Montana State University (USA), University of Antwerp (BE), Universidad de Concepción (CL), ETH Zurich (CH), La Trobe University (AUS), University of Kashmir (IN) + additional regional partners
RangeX: ETH Zurich (CH), University of the Free State (ZA), Aarhus University (DK), University of Bergen (NO), Swedish University of Agricultural Sciences (SE), University of Gothenburg (SE), CNRS / Université de Picardie Jules Verne (FR), Universidad de Concepción (Cl), University of Pretoria (ZA)
Duration:
MIREN: 2005 – ongoing
RangeX: 04.2021 – 03.2025
PIs in the institute: Sylvia Haider
Institute staff working on the project: Meike Buhaly (Leuphana), Lucia Santoianni (visiting researcher from University of Molise, ITA)
Website:
MIREN: https://www.mountaininvasions.org/
RangeX: https://rangex.w.uib.no/
2023 was the third year of work on the RangeX project and consisted primarily of writing and data analysis. The RangeX project is a Biodiversa project that seeks to better understand the processes and impacts of plants that are expanding their ranges following climate warming, and to use this knowledge to inform the development of policy regarding range-expanding plant species. We focus on mountain ecosystems as an ideal model system to address our research questions.
For our work in RangeX, we primarily use data collected by the Mountain Invasion Research Network (MIREN), a consortium of researchers all aiming to understand the effects of global change on species’ distributions and biodiversity in mountainous areas. MIREN was founded in 2005 with a focus on global monitoring of non-native plant invasions in mountains but has since expanded to the study of species redistribution under different drivers of global change including biological invasions, climate change, and land-use change. MIREN consists of standardized vegetation surveys along elevation gradients to evaluate and quantify the process and mechanisms that are shaping mountain plant communities at regional to global scales.
In 2022, our field work on the island of Tenerife was completed for both internal analysis as well as an addition to the MIREN global dataset. 2023 was spent answering questions such as: how do non-native species alter community composition over time on Tenerife? Are non-native species homogenizing communities at the regional to global scale? Can we predict range shifts of plant species in mountains using functional, range, and distribution traits? Look for these publications in the coming year!
In November, the RangeX team met in Glengarriff, Ireland for a productive writing retreat where we developed a framework to predict range shifts using a variety of biological and distribution traits.
THE NUTRIENT NETWORK
Partners: German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig
Duration: since 2015
PIs in the institute: Sylvia Haider
Website:nutnet.org
Hintergrund
Weltweit werden Ökosysteme von Menschen verändert, was in vielen Fällen zu einem erheblichen Rückgang der Biodiversität führt. Eine besondere Rolle spielt dabei die Nährstoffanreicherung durch Düngung und die Verbrennung fossiler Brennstoffe. So hat sich der globale Stickstoff- und Phosphorgehalt in Luft, Wasser und Boden seit der Industrialisierung verdoppelt bzw. verfünffacht. Gleichzeitig greift der Mensch massiv in Ökosysteme ein, indem er Lebensräume vernichtet und im Zuge von Jagd und Fischerei Bestände dezimiert. Auf der anderen Seite werden durch Viehhaltung oder im Rahmen von Naturschutz- oder Freizeitaktivitäten neue Arten eingeführt, so dass sich die Zusammensetzung grundlegend verschiebt.
Auch wenn die globale Bedeutung dieser menschlichen Aktivitäten schon lange bekannt ist, existierte bisher kein international koordinierter Forschungsansatz, um die Folgen im Detail zu untersuchen. Das internationale Forschungsnetzwerk „Nutrient Network“ (NutNet) hat es sich zum Ziel gemacht, die folgenden Fragen für Wiesen- und Weideökosysteme auf über 130 Standorten weltweit zu beantworten:
- Wie gut ist unser derzeitiges Verständnis über die Zusammenhänge von Ökosystem-Produktivität und Diversität?
- Inwieweit sind Produktivität und Diversität in naturnahen Weide- und Wiesen-Ökosystemen weltweit durch verschiedene Nährstoffe limitiert?
- Unter welchen Bedingungen können Pflanzenfresser oder Düngung die Biomasse, Diversität oder Zusammensetzung von Pflanzengemeinschaften maßgeblich beeinflussen?
Das Nutrient Network arbeitet mit einem einheitlichen Versuchsaufbau und stellt standardisierte Protokolle zur Verfügung, die auf allen Flächen weltweit zum Einsatz kommen.
Die Versuchsfläche in Bad Lauchstädt
Seit 2015 existiert auch auf der Versuchsstation Bad Lauchstädt eine Fläche des Nutrient Network und seit 2016 werden regelmäßig die Behandlungen mit Stickstoff-, Phosphat- und Kaliumsulfatdünger in unterschiedlichen Kombinationen durchgeführt. Jährlich werden Vegetationsaufnahmen gemacht, die Biomasse geerntet, Bodenproben genommen und die Lichtintensität gemessen. Diese Daten sind bereits in die zentrale Datenbank eingeflossen. Darüber hinaus nehmen wir an mehreren Zusatzprojekten teil, in denen unter anderem Stickstofffixierung, Fraßschäden durch Insekten und die Skalenabhängigkeit von pflanzlicher Artenvielfalt untersucht werden. Besonderer Fokus liegt in Bad Lauchstädt auf den potentiellen Veränderungen von Gemeinschaften und Prozessen im Boden.
©Sylvia Haider