Exploring the ecological effects of forest pests and diseases in a changing worldCase study
We leverage experimental and synthesised data approaches to create integrative models that predict the effects of pests and pathogens on forest ecology.
Tree pests and diseases are doubling every decade, some of which cause widespread damage to existing woodlands. Ash dieback (Hymenoscyphus fraxineus), a disease caused by an ascomycete fungus, has killed millions of ash trees in Europe. It is estimated to cost £15 billion in Britain, and a population decline of ash obligate and highly associated species. Forests across the world face similar challenges, where tree pandemics eradicate certain species within decades, followed by slow forest recovery.
The increasing interconnectedness of our world through trade and travel, and the lack of biosecurity, have accelerated the spread of invasive tree pests and pathogens. Despite plant sanitation regulations, the exponential growth of these threats continues. While early detection and response can sometimes be useful, in most cases, it is too late to effectively control the disease. In addition, some disease agents may suddenly reproduce fast when climate conditions exceed specific thresholds. In a world with rising temperatures and changing precipitation regimes, we are not sure whether this will lead to unforeseen disease outbreaks and severe ecological consequences.
This project focuses on predicting ecological effects of tree pests and pathogens in the future. As part of an NERC-funded project on ash dieback, we established experimental plots in Wytham Woods (Oxford) in 2020 to monitor the disease’s impact on tree health, nutrient cycling, habitat structure, woodland connectivity, and biodiversity. With the support of the Scottish Forestry Trust, we are developing a comprehensive global database of tree pest and disease outbreaks, covering a wide range of disease types. Through developing a wealth of data and modelling products, this project seeks to forecast future tree mortality rates, changes in nutrient cycling, and their consequences for forests in a changing world. This will be crucial for tree pest management and mitigating, which are important for successful nature recovery.
Project outputs
- Ecology
- A complexity-appropriate model was developed to forecast an invasive forest disease
- If 15 % of trees are resistant they create an efficient buffer against population decline
- Our modelling framework helps prediction, error assessment, and scenario building
- Ecology
- Ecology
Dahlsjö CAL (2023). Strategies to manage tree pest and disease outbreaks: a balancing act.. BMC Ecology and Evolution.
Tree diseases are one of the major threats to forests worldwide. As the frequency and severity of disease outbreaks increase, effective prevention and mitigation strategies are urgently needed. Emerging methods are available to tackle this issue, however, trade-offs and potential ecological consequences should be considered for successful forest preservation.
Wu H; Dahlsjö CAL; Malhi Y (2024). Evaluating the impact of an invasive pathogen on tree population decline: An evidence based modelling approach.. Forest Ecology and Management.
Highlights
Dahlsjö CAL; Malhi Y (2024). Unravelling a hidden synergy: How pathogen-climate interactions transform habitat hydrology and affect tree growth.. Science of The Total Environment, 954, 176325..
Interactions between multiple global change stressors are a defining characteristic of the Anthropocene. Tree-associated pathogens are affecting forested ecosystems worldwide and occur in the context of increased frequency and intensity of extreme climate events such as heat waves, droughts, and floods. The effects of these events, along with subsequent changes in environmental conditions, on remaining and regenerating trees, are not well understood but crucial for the restoration and conservation of forested habitats.
