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Urgent need to protect Earth’s forests from non-native pests

In a pivotal collaboration, CABI joined forces with a global team of researchers from 57 different institutions to examine the urgent necessity of safeguarding Earth’s forests. Their study emphasizes the critical need to shield these natural sanctuaries from non-native pests, particularly in the context of ongoing climate change.

Leading the study was Dr. Iva Franić, at the time a PhD student working under the guidance of CABI’s Dr. René Eschen. The research, published in the journal Scientific Reports, voices a pressing need to curb tree pests and bolster the resilience of forest ecosystems amid the surge of rising temperatures.

Contributing to this significant study were CABI’s own Dr. Marc Kenis and Dr. Hongmei Li. The scientists advocated for the understanding of the complex interplay between climate, host species, and geography. This understanding, they argue, is key to crafting strategies for preserving the world’s forests and the priceless benefits they offer.

How the researchers studied Earth’s forests

The study’s methodology involved an exhaustive survey of insects and fungi linked with dormant twigs of 155 tree species. The data was collected from 51 botanical gardens or arboreta in 32 countries, spanning six continents. The researchers were keen to identify the key factors influencing the differences within tree-associated communities.

Upon examination of the results, it became apparent that mean annual temperature, phylogenetic distance between hosts, and geographic distance between locations were primary factors in the observed dissimilarities.

Worryingly, the findings suggest that rising temperatures due to climate change could directly and indirectly affect tree-associated organisms by causing shifts in host ranges.

The researchers noted that insect and fungal communities displayed a higher degree of similarity when associated with closely related host species. This implies that shifts in host range could pave the way for the emergence of new pests.

They also found that variations among tree-associated communities increased with geographic distance, a clear sign that human-facilitated transport could aid the introduction of new pests into a forest.

What they learned about non-native pests

Dr. Franić, now part of the Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, explained the impact of climate on the findings.

She stated, “The study’s findings demonstrated that climatic factors played a crucial role in shaping the composition of fungi, particularly saprotrophic and plant pathogenic fungi, as well as herbivorous insects associated with trees.”

She further emphasized the influence of host-related factors, like phylogenetic distance and wood density, in defining these communities. The study found that closely related host species shared more species of insects and fungi, hinting at a co-evolutionary relationship.

Geographic factors also had a pronounced effect. The research revealed a distinct geographic structure within continents for both plant pathogenic fungi and herbivorous insects, indicative of limited dispersal between locations. However, the movement of plant material across continents could facilitate the introduction of new pests and pathogens.

Commenting on the research findings, Dr. Eschen said, “The findings of this study provide valuable insights into the complex dynamics of tree-associated communities and emphasize the importance of proactive measures to safeguard forest health in the face of environmental challenges.”

He went on to highlight that as climate change and global trade continually reshape our world, understanding and predicting these changes is crucial for the long-term sustainability of our forests.

In conclusion, the researchers stressed that ensuring the environmental and societal benefits derived from trees heavily depends on curtailing the establishment of new forest pests and improving the resilience of trees and forest ecosystems to climate change.

More about non-native pests

Non-native pests, also known as invasive species, are organisms that are not indigenous to a particular ecosystem and whose introduction causes harm to the environment, economy, or human health. Non-native pests can include plants, animals, insects, and microorganisms such as bacteria, viruses, and fungi.

Invasive species typically have several common characteristics:

Fast reproduction and growth

Non-native pests often reproduce and spread rapidly in environments where they have no natural predators or competitors. This allows them to establish themselves and displace native species quickly.


Non-native pests can be very aggressive, outcompeting native species for resources like food and habitat.


These pests often have high adaptability, meaning they can thrive in a variety of environmental conditions. This makes them particularly hard to control once they’re established in a new area.

Resistance to local pests and diseases: In their new environment, invasive species are often resistant to local pests and diseases that would normally help control their populations.

When it comes to impacts, non-native pests can cause extensive damage. They can out-compete native species for resources, alter habitats, disrupt ecosystems, and even drive native species to extinction.

Economically, they can cause significant damage to agriculture, forestry, and fisheries. For instance, invasive insects and plant diseases can destroy crops, while invasive aquatic species can disrupt fisheries.

Non-native pests can also pose a risk to human health. For instance, they can carry diseases that can be transmitted to humans or livestock.

Managing and protecting Earth’s forests

Managing non-native pests is often a challenging task, as complete eradication is rarely possible once a pest has become established. However, various control strategies can help manage their populations and mitigate the damage they cause.

These strategies include mechanical methods (such as physical removal), chemical methods (such as pesticides), and biological control (where other organisms, like insects, birds, or diseases, are used to control the invasive species).

Prevention is generally the most effective method of managing non-native pests. This includes measures like inspecting imported goods, controlling the movement of potentially infested materials, and public education about the risks and impacts of invasive species.

Efforts to manage non-native pests are ongoing globally. This involves collaboration between scientists, policymakers, and local communities.

The specifics of these efforts can vary depending on the pest and the environment it has invaded. For the most current information, it’s best to consult relevant governmental or scientific sources.

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