Newswise — CABI has become a crucial part of an international team comprising researchers from 57 institutions worldwide, contributing its expertise to a groundbreaking study. The research highlights the critical importance of safeguarding the world's forests from non-native pests, especially in light of climate change.
Headed by Dr. Iva Franić*, who was a PhD student co-supervised by CABI's Dr. René Eschen during the study, the research emphasizes the urgent necessity of controlling tree pests and bolstering the resilience of forest ecosystems in the face of escalating temperatures.
This significant study, which was published in the esteemed journal Scientific Reports, also involved the valuable contributions of CABI's Dr. Marc Kenis and Dr. Hongmei Li. The scientists contend that by comprehending the intricate interplay between climate, host species, and geography, stakeholders can formulate effective strategies to safeguard the world's forests and preserve the invaluable benefits they bestow.
The study encompassed an extensive survey focusing on insects and fungi present in dormant twigs of 155 tree species. This survey took place in 51 botanical gardens or arboreta, spanning across 32 countries and six continents. The primary objective was to understand the factors responsible for driving variations in tree-associated communities.
The findings revealed that three main factors played a crucial role in shaping dissimilarities among these communities. These factors were identified as mean annual temperature, phylogenetic distance between the host trees, and the geographic distance between the locations.
Of particular concern was the growing significance of high temperatures, which directly contributed to the observed differences in the studied communities. This finding implies that climate change could have both direct and indirect impacts on tree-associated organisms by influencing shifts in host ranges.
The researchers also made a noteworthy discovery: insect and fungal communities showed greater similarity when linked to closely related host species. This suggests that shifts in host ranges might pave the way for the emergence of new pests.
Moreover, they observed that dissimilarities among tree-associated communities increased with geographic distance, implying that human-mediated transport could be responsible for introducing new pests into forested areas.
Dr. Franić, who is currently affiliated with the Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, emphasized the importance of climatic factors in shaping the composition of fungi, especially saprotrophic and plant pathogenic fungi, as well as herbivorous insects associated with trees, based on the study's findings.
Furthermore, the study underscored the significance of host-related factors, including phylogenetic distance and wood density, in molding these communities. Notably, closely related host species exhibited a higher tendency to share common species of insects and fungi, implying the existence of a co-evolutionary relationship.
Geographic factors also emerged as significant influencers, with the distance between locations playing a critical role in shaping diversity. The research revealed distinct geographic patterns within continents concerning both plant pathogenic fungi and herbivorous insects, indicating limited dispersal between different locations. However, the exchange of plant material across continents could potentially introduce new pests and pathogens to these ecosystems.
Dr. Eschen, one of the co-authors of the research, stated, "The discoveries from this study offer valuable insights into the intricate dynamics of tree-associated communities and underscore the significance of proactive measures to protect forest health amidst environmental challenges. As climate change and global trade continue to shape our world, comprehending and foreseeing these changes will be vital for ensuring the long-term sustainability of our forests."
The scientists conclude by emphasizing that the preservation of the environmental and societal advantages derived from trees relies on two crucial aspects: first, limiting the establishment of new forest pests, and second, enhancing the resilience of trees and forest ecosystems to cope with the impacts of climate change.
Data set notes
The data set this paper is based on was published in March 2022 here: https://www.nature.com/articles/s41597-022-01162-3
Funding acknowledgement
The research was funded by the Swiss National Science Foundation Grant number 174644 and the Swiss Federal Office for the Environment (Grant 00.0418.PZ/ P193-1077). The work was also supported by COST Action “Global Warning” (FP1401).
Dr Franić’s PhD research
*The latest paper stems from work Dr Franić previously conducted as part of her PhD studies co-supervised by Dr Eschen.
In 2020, she obtained her PhD degree from the University of Bern in Switzerland, for her thesis entitled ‘The diversity of insects and fungi associated with trees: A plant health perspective.’
The research, which was led by CABI and the Federal Institute for Forest, Snow and Landscape Research (WSL) in Switzerland and funded by the Swiss National Science Foundation and related to COST Action Global Warning, assessed phytophagous insects and fungi in tree seeds purchased from commercial suppliers and fungi in tree seeds collected in botanic gardens in Europe and the USA.
The team also considered fungi and insects in dormant twigs from 32 countries to assess the diversity of such organisms and factors that may facilitate their establishment in other countries.
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