Relative importance of tree species and genotypic diversity for above- and belowground processes in boreal forest

Lead Research Organisation: Royal Holloway, University of London
Department Name: Biological Sciences

Abstract

The majority of forests in Europe are managed and underwent considerable changes in tree species richness, species composition and genetic diversity over the last few centuries. However, sound scientific evidence of the impact of these changes in tree species and genetic diversity on how the ecosystems work and the services they provide, including human well-being, is still lacking. We need this knowledge in order to effectively conserve and utilise our forests in the face of environmental change. Boreal forests are particularly species-poor, and therefore addition or loss of a single tree species may be expected to have larger effects on the ecosystem. In addition, the variation within tree species has also been recently shown to be an important determinant of ecosystem functioning, but the relative importance of variation between tree species and within a single species has not yet been addressed in a single study. In this project we take advantage of two unique long-term experiments previously established by our team in boreal forests of SW Finland. These experiments manipulate both tree species diversity and tree within-species genetic diversity. We will examine how this tree-based biodiversity affects the range of animals, microbes and fungi associated with the forest, how the ecosystems work, from above-ground insects to the tree's growth and the unseen but crucial biodiversity in the soil. A key connection between the trees and their associated biodiversity is their content of different chemical defences which protect them from their enemies and can have consequences for other organisms and ecosystem processes. Understanding the relative role of genetic and species diversity is important because we need to know whether conservation and management efforts have to be focused on species richness or intraspecific diversity. Therefore, the results of this project will be important for prioritizing conservation efforts and predicting consequences of biodiversity declines.

Planned Impact

The main types of non-academic beneficiaries of the proposed research are:

(1) Policy and decision makers in conservation science (e.g. Defra, Natural England, JNCC, Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES)):
This group of stakeholders will set the agenda for future conservation by establishing the parameters and providing levers especially via support schemes, to activate it. Following our failure to meet the 2010 targets to halt biodiversity loss, the utility of species and site-based conservation strategies is under scrutiny. Our research will provide evidence as to the effectiveness of conservation of biodiversity (of both genotypes and species) in relation to ecosystem function and will inform the decision-makers of the relative benefits of tree species and genetic diversity in woodlands.

(2) Woodland managers (e.g. Forestry Commission, the Woodland Trust, Scottish Natural Heritage) and forest owners:
The UK forestry standard guidelines published in 2011 declare the conservation of biodiversity an essential part of sustainable forest management in the UK. Results of our project will inform forest managers and forest owners on the effectiveness of use of tree species and genotype mixtures in forestry as a means of improving tree growth, reducing pest damage, and promoting the diversity and activities of beneficial soil fungi and bacteria. The tree species that will be used in the project (silver birch, Norway spruce, Scots pine etc) are economically important timber species in many European countries, and therefore the results of the project will be of practical relevance for forestry in the UK, Finland and elsewhere in Europe. We have already secured engagement of three stakeholders involved in woodland management: Forestry Commission, Scottish Natural Heritage and Coille Alba (a not-profit-sharing organisation based in Scotland which supports the sustainable management of native woodlands).

(3) International NGOs involved in conservation and forestry (World Wildlife Fund, IUCN, DIVERSITAS, International Union of Forest Research Organizations (IUFRO): our results will be of interest to the above organisations because our project focuses on boreal forests which is one of the world's largest terrestrial biomes stretching through North America, Europe and Asia. Only 9% of this biome is protected globally, and hence the relationship between biodiversity and ecosystem functioning in boreal forests is of particular interest. The international composition of our project team (PI in England, fieldwork in Finland, project partners from Germany and Estonia, subcontractors from Scotland and Finland) and PI Koricheva's involvement in two current EU projects (BACCARA and FunDivEurope) will facilitate engagement and dissemination of project results to the above international NGO organisations.

(4) Wider public: The general public are frequent recreational users of British woodlands and deeply care about their state of health. Recent public outcry which resulted in abandonment of government's plans to privatise England's forests demonstrates the impact general public has on policy and decision making on issues related to forest management. Our project will raise public's awareness about the relevance of woodland biodiversity in relation to forest ecosystem services.

The above stakeholders will be engaged in and informed about our project via: (1) participation in the two workshops that we are planning as part of the Pathways to Impact, (2) the planned involvement of PI Koricheva in UK IPBES Stakeholder Group, (3) the project summary booklet that we are planning to produce and disseminate among all relevant stakeholders; and (4) participation of project team in the Royal Holloway science festival and contribution to RHUL science blog. Details of our projects' dissemination plan are described in the Pathways of Impact.

Publications


10 25 50
 
Description 1. Effects of tree species and genetic diversity on tree growth. We found that effects of tree species and genetic diversity on tree growth depended on tree species/genotype. DBH of birch was higher in mixed stands whereas larch had higher DBH in monocultures. In the birch genetic diversity experiment, 2 genotypes displayed reduced radial growth in mixed stands whereas one genotype had higher DBH in genetically diverse mixtures.
2. Effects of tree species and genetic diversity on insect herbivores. Insect herbivore damage on birch was lower in mixed thinned stands than in thinned birch monocultures whereas herbivore damage on alder was higher in mixed stands. Birch genetic diversity did not affect herbivore damage and species richness of specialized herbivores (leaf miners), but significantly affected herbivore species composition.
3. Effects of tree species and genetic diversity on litter decomposition. We used cellulose as a standard decomposition substrate to allow comparison of potential decomposition rates across both experiments. In tree species diversity experiment potential decomposition increased with species diversity in thinned plots. There were no significant differences in rate of decomposition between litter bags with different mesh sizes, suggesting that microbes were driving the observed patterns. No significant effects of birch genetic diversity on potential decomposition were found.
Exploitation Route Our project provides unique contribution to the scientific field of biodiversity and ecosystem functioning because it is the first study which has examined the relative the relative role of tree species and genotypic diversity on a variety of ecosystem processes in boreal forests. The Satakunta experiments are the oldest within the TreeDivNet )global network of forest diversity experiments) and the only experiments in boreal forest biome in this network. the methodological and conceptual approaches developed within our project can now be applied to other forest diversity experiments around the world to gain the understanding of the relative importance of tree species and genetic diversity at the global scale.
Results of our project will also inform forest managers and forest owners on the effectiveness of use of particular tree species and genotype mixtures in forestry as a means of improving tree growth, reducing pest damage, and promoting ecosystem resilience to environmental change and diversity and activities of beneficial soil fungi and bacteria. For instance, our results suggest that growing birch in mixtures with other tree species (especially conifers) increases radial growth and reduces pest damage whereas increasing genetic diversity of birch stands does not provide the same benefit. We intend to communicate the results of our project to stakeholders in the final project workshop in April 2017.
Sectors Environment
URL http://www.ingentaconnect.com/content/sil/impact/2017/00002017/00000001/art00021
 
Description James Hutton Institute 
Organisation Scottish Government
Department James Hutton Institute
Country United Kingdom of Great Britain & Northern Ireland (UK) 
Sector Public 
PI Contribution We have provided the James Hutton Institute with samples for leaf and litter chemical analysis (summer 2015) and soil samples (summer 2016) for chemical and microbial analyses.
Collaborator Contribution The James Hutton Institute was subcontracted by RHUL to conduct leaf and litter chemical analyses, analyses of basic soil chemical parameters, and the soil microbial community metabolic profiling. So far we have been provided results of chemical analyses of leaf and litter, including lignin, ADF, C, N, proanthocyanidins, and protein precipitating capacity. Analyses of soil samples are under way.
Impact Two manuscripts based on chemical analyses of leaves are currently in preparation. One paper (led by PhD student Evalyne Muiruri) is focusing on the role of leaf physical and chemical traits as predictors of insect herbivory on birch and effects of tree species diversity on these relationships. The second paper led by PDRA Sandra Barantal is comparing effects of tree species and within-species genetic diversity on birch leaf miner abundance and species richness, using leaf chemical data to calculate functional diversity indices.
Start Year 2014
 
Description Natural History Museum, University of Tartu, Estonia 
Organisation University of Tartu
Country Estonia, Republic of 
Sector Academic/University 
PI Contribution We have collected fine root samples from the Satakunta Forest Diversity Experiment and made them available to Leho Tedersoo's group at University of Tartu for fungal DNA analyses.
Collaborator Contribution The project partner Leho Tedersoo from Natural History Museum, University of Tartu, Estonia, contributed to the project by pre-processing soil samples for molecular analysis of ECM using Illumna sequencing at no additional costs to the project. The samples are now being sequenced at NBAF Liverpool.
Impact This is interdisciplinary collaboration between forest ecologists (RHUL) and molecular mycologists (Leho Tedersoo, University of Tartu), which has started in 2011 when Dr Tedersoo's group has first visited the Satakunta forest diversity experiment and collected soil samples. This work (which pre-dates the current NERC project) resulted in development of a DNA metabarcoding approach to identify the major eukaryote groups directly from soil with roughly species-level resolution and publication of joint paper on tree diversity and species identity effects on soil fungi, protists and animals (Tedersoo et al. The ISME Journal (2016) 10, 346-362).
Start Year 2011
 
Description University of Turku 
Organisation University of Turku
Country Finland, Republic of 
Sector Academic/University 
PI Contribution We have provided Prof Salminen's group at University of Turku with birch leaf samples collected from the Satakunta Forest Diversity Experiment for the analysis of oxidative capacity of phenolics.
Collaborator Contribution For analyses of oxidative activity of birch leaf tannins RHUL subcontracted Prof Juha-Pekka Salminen from Department of Chemistry, University of Turku, Finland, who is an international expert in tannins and their role in plant-herbivore interactions. His lab has recently developed a new method to estimate the oxidative activity of all types of tannins and other phenolics by the 96-well plate reader; this method was used in the current project to examine variation in oxidative activity of birch leaves from pure and mixed stands and its effects on insect herbivory
Impact This is a multidisciplinary collaboration between ecologists (RHUL) and biochemists (University of Turku). The analysis of the results of chemical analyses of phenolics is currently underway and should inform us about the effect of tree species and genetic diversity on chemical suitability of birch foliage for insect herbivores.
Start Year 2014
 
Description iDiv 
Organisation German Centre for Integrative Biodiversity Research (iDiv)
Country Germany, Federal Republic of 
Sector Charity/Non Profit 
PI Contribution We have provided Prof Eisenhauer's group with soil samples from the Satakunta Forest Diversity Experiment for analysis of soil microbial respiration.
Collaborator Contribution The team of project partner Prof Nico Eisenhauer (iDiv, Germany) contributed to the project by performing soil microbial respiration measurements, which will allow us to infer the functioning, resource use efficiency and resource status of the soil microbial community.
Impact Analyses of the results of soil microbial analyses are still ongoing and will reveal the effects of forest tree species and genetic diversity on soil microbial respiration.
Start Year 2013
 
Description Poster at the Gordon Research Conference on Plant - Herbivore Interactions in California 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Poster entitled "Effects of tree genetic and species diversity on leaf miner communities associated with silver birch" has been presented by Julia Koricheva at the Gordon Research Conference on Plant - Herbivore Interactions in California, USA in February 2017. The poster generated many questions about the possible mechanisms of forest diversity effects on herbivores and differences in effects of tree species and genetic diversity.
Year(s) Of Engagement Activity 2017
 
Description Presentation at IUFRO regional congress 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact A talk entitled "Relative importance of tree species and genetic diversity for ecosystem functioning boreal forests" has been given by Sandra Barantal at the IUFRO regional congress for Asia and Oceania in October 2016. It has been followed by questions and discussion about methodology and practical importance of the study.
Year(s) Of Engagement Activity 2016
 
Description Presentation at the European Ecological Federation conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Results from the project were presented at the the 13th European Ecological Federation (EEF) and 25th Italian Society of Ecology's (S.It.E.) joint conference in Rome, Italy, on September 23rd 2015 as part of the symposium 'Biodiversity and Ecosystem Function experiments with trees'. Sandra Barantal discussed relative importance of tree species and genetic diversity for leaf miner communities on birch, which generated discussion afterwards about feasibility of similar studies at other forest diversity experiments across the world.
Year(s) Of Engagement Activity 2015
 
Description RHUL workshop 1 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact As part of the Pathways to Impact for the NERC project we have organized at RHUL workshop on forest diversity effects on ecosystem functioning, which took place on April 25th 2014. It was attended by 18 people in total, including all project participants and project partners, leading experts in the field of forest diversity and ecosystem functioning from the UK, France and Germany, as well as woodland managers from RSPB, Scottish National Heritage, Crown Estate, and Forest Research. The workshop sparked discussion between forest managers and researchers about the importance and practicalities of maintaining and managing forest diversity.
Year(s) Of Engagement Activity 2014