Policy brief: “Landscape diversity enhances human health”
Diverse agricultural and forest landscapes enhance human physical and mental health. Even small land use changes can introduce health risks into the environment.
Landscape diversity refers to the variety and spatial arrangement of different ecosystems and landforms within a specific area. It supports species diversity and is essential for ecological processes and functions, thereby playing a crucial role in the ecosystem services that nature provides for human health and well-being. However, significant land use changes and intensification have led to landscape homogenisation, reducing biodiversity and the benefits it provides.
In 2018, Biodiversa+ launched the BiodivHealth call to support research at the intersection of biodiversity and health. This brief presents findings from FUNPROD, Dr.FOREST and ANTIVERSA on how diverse agricultural and forest landscapes enhance human physical and mental health and, conversely, how even small changes in land use can introduce health risks such as tick-borne diseases and antimicrobial resistance into the environment. The brief further suggests practices that can promote landscape heterogeneity to improve both biodiversity conservation and human health outcomes.
Agricultural landscapes
Higher landscape diversity boosts both functional and species diversity, enhances regulatory ecosystem services, and benefits human health. Although intensification can increase short-term crop yields, it homogenises landscapes and weakens agro-ecosystem health and resilience. Eco-friendly agricultural practices that promote landscape diversity can enhance ecosystem services, improve food quality, and support social well-being and mental health.
From biodiversity to health: Quantifying the impact of diverse ecosystems on human well-being
While biodiversity likely benefits health, clear evidence is limited. This work offers a roadmap for assessing biodiversity’s impact, presenting models linking environmental conditions to well-being through ecosystem services. It calls for holistic, long-term research to inform conservation policies and understand well-being trade-offs and perceptions.
Increasing landscape complexity boosts overall biodiversity but doesn’t necessarily enhance multiple ecosystem services simultaneously. Relationships between yield and bird richness or biological control improve, while bird and plant richness relationships turn negative. This challenges the assumption that biodiversity-friendly management always promotes multiple ecosystem services and calls for further research.
This study proposes a conceptual framework to understand how functional diversity impacts human health, highlighting the complex interplay of services and disservices within agroecosystems. Increasing network complexity and multifunctionality can enhance both regulating and provisioning services, promoting sustainable agriculture.
- Protect diverse agricultural landscapes by incentivising farmers and providing them with technical support to maintain mixed land uses, smaller fields, semi-natural patches, diverse cropping systems, and agroforestry as part of implementing the Common Agricultural Policy (CAP) 2023-27.
Forests
Intensive forest management has led to simplified, less resilient forests in Europe. These forests are more vulnerable to threats like fire, pests, and damage, impacting their ability to provide wood, sequester carbon, and support human health. Forests offer numerous health benefits, including reduced heat stress, improved air quality, and enhanced mental well-being. Canopy density and tree species diversity are key factors influencing these benefits. Sustainable forest management should consider the complex relationship between forest characteristics and human well-being.
Particulate matter (PM) pollution is a significant health threat, and trees help mitigate it by filtering PM. An analysis of data from 57 publications found evergreen conifers accumulate the most PM, with traits like epicuticular wax playing a crucial role. The highest PM loads were in peri-urban areas, but data is skewed towards urban and peri-urban areas, especially in China and Poland, highlighting the need for more research.
Forest biodiversity and structure modulate human health benefits and risks
Forests provide net health benefits, driven by canopy density and tree species diversity. However, changes in canopy density can create trade-offs, like improving heat buffering and air pollution mitigation but reducing medicinal plant yield and increasing Lyme disease prevalence. Tree diversity generally has positive, though weaker, effects. Forest management should consider these trade-offs for local public health needs.
Forest Diversity Reduces the Prevalence of Pathogens Transmitted by the Tick Ixodes ricinus
Tick-borne diseases, mainly spread by Ixodes ricinus in forests, are the most common vector-borne diseases in Europe. Tree species identity and canopy density influence tick abundance and infection rates, with higher tree diversity reducing infected nymphs, highlighting the importance of forest composition and diversity in managing tick-borne diseases.
Integrating Tree Species Identity and Diversity in Particulate Matter Adsorption
The amount of particulate matter (PM) bound by tree canopies depends on leaf traits and leaf area, both influenced by tree identity. In a study of four species, Tilia cordata and Carpinus betulus had higher PM2.5 per m² leaf area. Polycultures, especially those including Quercus robur and Carpinus betulus, showed higher PM accumulation, indicating that both tree identity and mixture affect PM binding.
Urban tree canopies drive human heat stress mitigation
Climate warming and urbanisation increase heat-related health risks, which can be mitigated through urban greening. A study in Ghent, Belgium, found that tree canopy cover significantly reduces daytime heat stress, lowering temperatures by up to 8.8 °C mPET during heat peaks, though it provides minimal relief at night due to the urban heat island effect.
Forests are chill: The interplay between thermal comfort and mental wellbeing
Trees and forests can mitigate heat and improve mental wellbeing. A study in Austria, Belgium, and Germany found that forests reduced perceived temperature by 9.2 °C on average, with high diversity forests being the coolest. Forests also improved thermal comfort and mental wellbeing, suggesting a synergy between these benefits.
This study in three European peri-urban forests found that 20-minute forest visits improved short-term mental health and well-being, with perceived biodiversity linked to better outcomes, while actual tree species richness had no significant effect. Understanding these links can help develop nature-based public health interventions.
Temporal dynamics of acoustic diversity in managed forests
In production forests, higher silvicultural management intensity (SMI) reduces acoustic diversity by affecting forest structure and bird diversity. Acoustic diversity indices provide insights into how forest management influences species diversity and vocal activity, informing better forest management practices.
- Accelerate the implementation of EU commitments to plant an additional 3 billion trees by 2030 as a nature-based solution under the European Green Deal for climate change mitigation and adaptation, using mixed stands of native trees.
- Restore diverse forests with a variety of tree species, ages, and sizes. Forest diversity can be promoted under the EU Nature Restoration Law. State aid Guidelines under the CAP can incentivise the implementation of the European Commission’s voluntary Guidelines on closer to nature forest management that aim to improve forest diversity as part of the new EU Forest Strategy.
- Integrate mixed species stand of forests and other green infrastructures into urban and landscape planning to support the specific health needs of local communities. For example, include native evergreen conifers in urban forests to maximise the removal of particulate matter air pollution, or promote dense canopies to protect against heat stress, intermingling stands with deciduous trees to enhance biodiversity and resilience. This can be integrated into the EU Nature Restoration Law, which aims to steadily increase green urban space areas and tree cover by 2030. Enhancing biodiversity as a nature-based solution to protect human health within urban areas can also be included in the Urban Agenda for the EU and the Green City Accord.
- Raise awareness of the significant mental health benefits of nature. Educate public health practitioners, doctors, and the general public about the mental health benefits of biodiversity. Programmes like Dose of Nature, which encourages spending time in nature to help with mental health issues, are examples of the practical application of these findings.
Rivers
Factors promoting and limiting antimicrobial resistance in the environment – Existing knowledge gaps
The spread of multidrug-resistant bacteria and antibiotic resistance genes is a major global issue. The WHO emphasises the need to contain antimicrobial resistance (AMR) from all sources. International collaborations and projects have developed strategies to inhibit AMR spread. This mini-review highlights overlooked aspects crucial for understanding AMR, especially within the One Health approach.
This study found six out of nine antibiotic resistance genes (ARGs) in all effluent and river water samples from 16 wastewater treatment plants across ten European countries. ARG abundance was inversely correlated with the number of biological treatment steps, suggesting a management option. The study also identified blaOXA-58 as a potential gene for future research.
- Protect rivers and riparian areas from antimicrobial resistance. Strictly regulate livestock grazing near water sources to prevent water pollution and avoid the spread of antimicrobial resistance. This can be implemented under the Water Framework Directive. The revised Urban Wastewater Treatment Directive can require additional water treatment steps in wastewater treatment plants to minimise antimicrobial resistance in water discharged into the environment.
