Dr. Sanju Deenapanray, Founder and Managing Director, ELIA-Ecolgical Living in Action | Sutainability and Climate Change Programme, Université de Mascareignes
Xavier G. H.Koenig, Sustainability and Climate Change Programme, Université des Mascareignes
Dr. Vincent Florens, Associate Professor, Tropical Island Biodiversity, Ecology and Conservation Pole of Research, Department of Biosciences and Ocean Studies, Faculty of Science, University of Mauritius
Dr. Pricila Iranah, Indian Ocean Islands Foundation
Dr. Vikash Tatayah, CEO, Mauritian Wildlife Foundation
Summary
Human health does not exist in isolation. This is the principle at the heart of the “One Health” concept, which recognises inextricable links between the well-being of people and nature. Guided by this holistic approach, a new study suggests that small islands may offer an unusually clear vantage point on some of the world's biggest challenges.
The idea that nature is essential to human well-being is far from new. For centuries, philosophers have argued that nature is inherently valuable (Palmer et al., 2014), while Indigenous Peoples rooted human-nature relationships in reciprocity (Redvers et al., 2022). Yet, modern societies are largely founded on exploiting nature. Nevertheless, a holistic approach is gaining momentum across global policy frameworks: “One Health”. With a growing body of supporting evidence, “One Health” (Gupta et al., 2019) links human, animal, and environmental health, but can be extended beyond its conventional human-animal-environment framing toward planetary health.
But why is it important to recognise human-nature relationships? This study turns to small island developing states (SIDS) to answer this question, with Mauritius as a central example of “all that shouldn’t be done to an island” (Adams and Carwardine, 2009).
Why focus on islands?
Although oceanic islands are amongst the last places on Earth to be reached by humans, they are also often the most rapidly and severely affected by human activities (Fernández-Palacios et al., 2021; Russell and Kueffer, 2019). Because an island is small and bounded, albeit open to external flows of people, goods, and species, it works like the planet in miniature. The planet is itself a materially closed system except for the influx of solar energy. Therefore, islands offer unique settings of high priority for mapping out how socioecological dynamics affect ecosystems.
Key findings
By synthesising evidence from existing case studies, researchers mapped the human-nature interactions shaping the health and well-being of island communities. The resulting causal diagram (Figure 1) reveals that the vulnerability of SIDS to ecosystem decline, social injustice, and health inequity are deeply interconnected.
Figure 1: Causal diagram of primary dynamics affecting health and well-being in SIDS.
Shared legacies of ecological devastation and social inequity
Damaged ecosystems, social injustice and poor health are not separate. They are produced together, by the same forces and out of the same history, so they cannot be fixed one at a time. They are linked via two intertwined drivers: (1) the environmental damage caused by human activity, and (2) the unequal access to land, nature, and the benefits they provide, much of it inherited from colonial rule.
On most SIDS, the prevailing threats to their ecosystem health can be traced back to their colonial pasts. They often share a history of rapid deforestation where vast areas of native forests were cleared to make way for plantation economies, extractive industries, and/or military infrastructure (Grove and Rackham, 2001; Lewis, 1999). Such practices drastically altered island ecosystems, driving biodiversity loss, fragmenting habitats, and leaving them increasingly vulnerable to novel threats like invasive alien species. In Mauritius, for example, only 4.4% of the original native vegetation cover remains (Hammond et al., 2015). The surviving remnants are small fragments scattered across a mosaic of ongoing urban development and large-scale plantations, especially of sugarcane.
Even after independence, this legacy of ecological transformations has continued through new avenues of economic development with many SIDS shifting towards tourism, offshore finance, export processing, and real-estate development. The resulting land-use changes are deepening social disparities left behind by colonisation. Historical patterns of land ownership and development continue to benefit the elite, while excluding local communities who ultimately bear the costs of environmental decline (Fletcher et al., 2020; Scheyvens and Russell, 2012).
For instance, across the Caribbean and Indian Ocean, beachfront developments for tourism and luxury residences have displaced fishing communities. In the process, these communities have had their access to resources vital to their livelihoods and food security restricted or even cut off (Blythe et al., 2018). At the same time, such developments are detrimental to neighbouring coastal ecosystems, imperilling the very habitats that sustain these essential resources.
The same plantation economies that reshaped island landscapes also narrowed what people could grow and eat, leaving many islands dependent on imported, heavily processed food. This shift in diet has driven high rates of diabetes, obesity, and heart disease across small island states, making these chronic illnesses one of the region's heaviest health burdens(Connell, 2013; McElroy and Albuquerque, 1998).
Urbanisation, pollution and the environment-health nexus
As built-up areas continue to expand, they increasingly limit the availability of natural habitats for wildlife. As a result, humans and their domestic animals are brought closer to wild animals, creating more opportunities for the spread of zoonotic diseases (Keesing and Ostfeld, 2021).This can be especially consequential on islands, where limited space and high population density can amplify outbreaks.
Public health risks associated with urbanisation are not only driven by proximity to wildlife, but also by broader environmental changes. With the rise of tourism and urban development, greater volumes of industrial and residential pollutants are released into the environment. Water pollution is of particular concern, given the growing issue of freshwater scarcity. Contaminations could further strain water supply, as well as place people at risk of contracting waterborne diseases (Parker et al., 2023).
However, the consequences of water pollution extend well beyond the availability of freshwater and emergence of vector-borne diseases. Mauritius experienced this firsthand in 2020, when the MV Wakashio oil spill affected large stretches of its southeastern coastline. This environmental disaster exposed the vulnerability of coastal communities, especially women, who lost both their revenue from tourism and access to subsistence fishing (De Rosnay et al., 2021; Naggea et al., 2021).
The compounding effects of climate change
In this fragile context where SIDS are already susceptible to numerous ecological and socioeconomic challenges, climate change is intensifying their existing vulnerabilities. Rising sea levels, increasing temperatures, and extreme weather events such as droughts are amongst the many climate hazards affecting small islands (Duvat et al., 2017).
Climate hazards are not only interacting with one another but also with other non-climate drivers such as unsustainable land uses, amplifying their overall impacts (Boodoo and Deenapanray, 2021). Evidence shows that this leads to reduced food production and depleted freshwater resources, disproportionately affecting communities that are already disadvantaged (Guell et al., 2024; Mycoo and Roopnarine, 2024).
Climate change therefore works in a self-reinforcing cycle, where environmental degradation and climate vulnerabilities reinforce one another.
The research further reveals the profound effects of climate change on human health. Through the loss of lives, livelihoods, infrastructure, access to essential services, climate-related disasters can cause grief, anxiety and trauma amongst other psychological impacts (du Bray et al., 2017; Furusawa et al., 2021; Kelman et al., 2021; Lohmann et al., 2019; Nunn and Kumar, 2018; Park et al., 2025; Smith, 2024; Williams, 2025). These are particularly pronounced in island communities, whose identities and cultural heritage are tightly interwoven with their ecosystems.
What needs to change?
This research calls for the recognition of healthy ecosystems as the foundation of healthy communities. The cause-and-effect framework developed through this research provides a better understanding of the complex interactions that shape human and environmental health. Environmental decline and public health should no longer be addressed in isolation, but through holistic “One Health” approaches that also prioritise social equity. For SIDS, this means implementing policies that:
- enforce sustainable land management,
- invest in biodiversity conservation and ecosystem restoration,
- strengthen climate resilience and adaptation, and
ensure fair access to natural resources.
Using islands systems as models, researchers and policymakers can hence develop integrated solutions that not only address local challenges but also help build healthier, more resilient, and more equitable futures globally.
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