Human Health and Ecosystem Management (HHEM)

Group lead: Carlos Zambrana-Torrelio

Senior Research Scientist
Group co-chair: Paula Ribeiro Prist

EcoHealth Alliance, New York, USA

Human health is closely linked to the health of our ecosystems and is a compelling example of integrating nature and biodiversity to promote its wider value. Evidence is increasingly emerging linking environmental degradation with the loss of human health, but these relationships are complex and still poorly understood. This thematic group seeks to understand the relationships between ecosystem management, and human health, and to develop strategic research agendas to generate the knowledge needed to prevent future pandemics and include human health maintenance into policy decisions.

Human health is intimately interconnected with biodiversity and the health of our ecosystems and is a compelling example of mainstreaming biodiversity and ecosystems to promote their broader value. For example, biodiverse influence the provision of natural products and genetic resources, which form the basis for both traditional medicine and modern pharmaceuticals. An estimated 70–80% of the global population depend on some form of traditional medicine for their primary health care and seventy-five percent of all antibacterial, antiviral and antiparasitic drugs approved by the United States have natural product origins (Marselle et al. 2021). Biodiversity also affects physical health - people living in more biodiverse areas and exposed to higher fungal and fauna diversity are less likely to develop allergic sensitization and to have improved lung function (Marselle et al. 2021). In addition, the evidence points out that ecological communities with a high diversity favor the dilution effect of reservoir species and reduce the risk of the spread of diseases. This is related with the probability of host communities with a high richness of species, that have a greater proportion of inefficient hosts for infectious agent transmission.

However, human activity is rapidly transforming most of Earth’s natural systems. Since 1990, it is estimated that 420 million hectares of forest have been lost through conversion to other land uses (FAO, 2020), with agriculture expansion being one of the main drivers of deforestation and forest degradation and the associated loss of forest biodiversity (FAO, 2020). Because of this, hundreds of species are lost each year, with declines in both richness and abundance. For example, 322 terrestrial vertebrates have become extinct since 1500, and populations of the remaining species show an average decline of 25% in abundance (Dirzo et al., 2014). Currently, growing evidence have suggested that natural system loss and degradation can affect human health in a variety of important ways and the increasing pace and extent of these changes has prompted this Perspective.

Considering this, the point has been made that the conservation or even restoration of natural environments could be important to the maintenance of human health and even to prevent future pandemics (Mansuy 2020; Boriani et al. 2021) by integrating the One Health approach. However, these relationships are complicated and there are trade-offs that need to be considered. For example, at the same time that ecological communities with a high diversity favour the dilution effect of reservoir species and reduce the risk of the spread of diseases, forested and species-rich areas might also be at high risk for disease emergence.

The creation of protected areas has historically been the forest governance instrument most often adopted to pursue biodiversity objectives. This approach has achieved positive results in terms of conserving species and establishing barriers to the progress of deforestation. Moreover, the evidence suggests that these areas may be important to barrier disease transmission, with the presence of these areas being related to better health outcomes. However, alone they may not be enough to conserve biodiversity, because they are usually too small, create barriers to species migration and are vulnerable to factors such as climate change, factors that can also affect human health. This means that there is a need to look beyond protected areas and to mainstream biodiversity conservation and the maintenance of human health into landscape management practices.

There are ways to manage the world’s forest ecosystems that will ensure the conservation and sustainable use of their biodiversity and that will guarantee the maintenance of human health. In addition, the demonstration of the biodiversity value as a protective barrier against zoonotic disease outbreaks have implications for ecosystemic preservation as well as public and animal health.  i) Pathogens may exacerbate the reduction of animal species that are at risk of extinction; ii) 60% of zoonotic diseases originate from wild animals that come in contact with humans due to anthropogenic disturbances; iii) the primary generators of change in a community are their own inhabitants.

However, to guarantee these effects it is fundamental to understand how changes in the environment and biodiversity affect human health, so that preventive measures and assertive landscape management can then be suggested.

Based on this, we will explore the relationships between human and ecosystem health, well-being, and biodiversity, in their most complex forms. Integrating human health objectives into natural resource management promotes positive feedback and co-benefits between ecosystem health and biodiversity conservation and can provide programmatic advantages for organizations seeking public buy-in. The main priorities of our group are:

  • Identify the strength of relationships between disease emergence and its hypothesized drivers; and apply these relationships to models for ecological restoration and rewilding.
  • Determinate the epidemiological, ecological and socio-economic indicators indispensable for the protection and/or reduction of disease risk of protected areas.
  • Justify the necessity to take into account the biodiversity and protected areas for the reduction of disease outbreaks. These include primary factors related to ecological and political aspects.
  • Evaluate epidemiological, ecological and socio-economic indicators involved in the risk of bidirectional transmission, outbreak and maintenance of diseases.

Projects and Initiatives
Promoting healthier landscapes through ecological restoration: The need for comprehensive guidelines

Zoonotic diseases represent 75% of emerging infectious diseases worldwide, and their emergency is mainly attributed to human-driven changes in landscapes: deforestation, forest fragmentation, and land use change. Although these links are becoming better understood, very few studies have investigated the outcomes, whether positive or negative, of restoration initiatives on disease outbreaks. In this project we reviewed the existing evidence linking restoration with spillover risk, identified knowledge gaps, and propose restoration management strategies that can limit the spread of zoonotic risk. We identified a large knowledge gap about the effects of restoration on zoonotic diseases, especially in tropical regions. In addition, the few studies that exist do not consider aspects that are determinant for the outcomes of restoration, such as the environmental history of the landscape and its structural characteristics. With this in mind, our conceptual model raises two important points: (1) the effects of restoration will depend on the context of the existing landscape, especially the percentage of native vegetation existing at the beginning of the restoration; (2) these effects will also be dependent on the spatial arrangement of the restored area within the existing landscape. In addition, we propose a roadmap for integrating the risk of zoonotic diseases as criteria into restoration planning, to minimize the potential adverse effects and optimize positive effects. Synthesis and application: Our results contribute to a more comprehensive landscape restoration planning that comprises multiple ecosystem services resulting in healthier landscapes for both people and nature and could be integrated into the post-2020 global biodiversity framework targets that aim at restoring ecosystems.

Integrated Nature-based Solutions to Reduce Zoonotic Risks 

Nature-based solutions (NbS), designed to address environmental challenges, have been suggested as important tools to mitigate emerging infectious disease outbreaks and even to prevent future pandemics by integrating the One Health approach. However, to date, most NbS have been targeted at climate change mitigation, with a lack of studies that substantiate the relationships between NbS and human health. Because of this important suggestion, it is essential to understand if NbS can affect spillover risk and in which configuration they should be implemented in order to be effective. To fill this research gap, we performed a literature review and draw attention to some important points that should be considered before implementing this strategy in order to have win-win benefits. We found 14 articles relating NbS and emerging infectious diseases, and most of them were evaluating NbS type 3 (n=79%) – design and management of new ecosystems – with most of them studying urban green areas. NbS type 1 – minimal intervention - appear only in two studies, and none evaluated the effects of NbS type 2 – guidelines and protocols. In addition, studies have shown that NbS may not always bring positive results for human health, with the configuration of green areas being an important factor in determining spillover risk. This opinion paper introduces a concept that goes one step beyond simply attesting that NbS can be good for pandemic prevention: we propose that it depends on how NbS are implemented. We also point out which important issues should be studied in the coming years in order to have a better knowledge about how to maximize the intended effects of NbS on human health, especially on the transmission of zoonotic diseases, and which should be the best way to implement it

Economic and health impacts of indigenous land protection in the Brazilian Amazon

Over the past few years, the Amazon basin has been facing increased frequency and intensity of forest fires, which release toxic particulate matter (PM2.5) negatively affecting human health. Indigenous territories can be important for conservation, but still little is known about how much these areas can contribute to the maintenance of human health. Here we quantified human health benefits of forested indigenous territories and estimated the economic benefits of keeping these areas protected. Between 2010 to 2019, 1.68 tons of PM2.5 were released every year, causing an incidence of 587 respiratory and cardiovascular cases in the Brazilian Amazon. At the same time, the Amazon Forest had the potential capacity to absorb 26,376.66 tons year−1, 27% of this by the indigenous territories. By protecting these areas, over 15 million respiratory and cardiovascular cases could be avoided, with estimates of $2 billion USD being saved to the Brazilian government.

Any recent publications, external links to any relevant work related to the group.