Special issue, ‘mountain life,’ celebrates Alexander von Humboldt’s lasting legacy

Alexander von Humboldt was born 250 years ago this month, and while he spent much of his life studying Earth’s mountainous regions, his vision of how science is intertwined with the broader human experience has helped to lay the groundwork for aspects of modern science more broadly. In this special issue of

Science

, an Editorial, a Perspective, four Reviews and a Policy Forum highlight von Humboldt’s lasting legacy on issues related to the ecology and environment of mountains, in particular. These pieces also discuss how his ideas could help humanity better address societal challenges we face in the Anthropocene.

Mountains cover 25% of the Earth’s surface but are home to more than 85% of the planet’s species of amphibians. As described in a Review by Carsten Rahbek and colleagues, the causes of this species richness remain an open question. Rahbek et al. call this “Humbolt’s enigma,” and they provide an overview of the research focused on mountain ecosystems worldwide that is attempting to solve this riddle. The authors suggest that the complex interactions between climate and rugged mountain terrain likely played a key role in both generating and maintaining species diversity in the mountains. However, with global climate change and increasing human land use in mountainous environments, their long history as refugia for biodiversity could be threatened. In a second Review, also led by Rahbek, the authors discuss how diverse mountain environments evolved. Their Review highlights how geological and long-term climatic processes shaped global patterns of mountain biodiversity over millions of years.

A third Review by Frank Hagedorn and colleagues discusses the interconnected nature of mountain vegetation and the wildly diverse, yet largely unseen, microbial soil communities in the ground below. While the responses of mountain vegetation to increasing human activity and a changing climate have been well studied, the resulting changes to the soil communities below ground are much less understood. Hagedorn et al. identify how these underground ecosystems might respond to vegetation shifts due to climate change and how this could impact short- and long-term carbon and nutrient cycling, both of which are critical to overall ecosystem function. The authors suggest that the often-overlooked soil biota should be integrated into existing vegetation monitoring programs in order to best assess belowground ecosystem change and its interaction with the changing environments above.

A fourth Review, by Andrea Encalada and colleagues, focuses on tropical montane rivers (TMR) – waterways born in tropical mountains, which often feed into major lowland rivers, floodplains and oceans. They are one of the planet’s most understudied ecosystems. Encalada et al. provide a global perspective on TMR and highlight the vast array of ecosystem functions and services they provide to plants, animals and humans worldwide. According to the authors, TMRs are studied under specific contexts but rarely as holistic, dynamic systems that span large elevation and temperature gradients. This unique property allows them to be used as natural model systems to better understand the effects of rapid change, such as those from human or climate impacts, on biodiversity and ecosystem functioning across broader spatial and temporal scales.

In a Perspective, author Stephen Jackson reflects on Humboldt’s unique fusion of science with the broader human experience. To Humboldt, nature and humanity are inextricably entwined – a more than 200-year-old observation that has become increasingly clear as our varied impacts on Earth’s environments bring reciprocal influences to bear on human welfare. According to Jackson, Humbolt’s vision offers a way to address some of the most pressing environmental and social challenges we face in the Anthropocene. “Rekindling Humbolt’s vision, and building on his legacy, can provide not only solace and inspiration, but maps and narratives toward a better future for nature and people,” Jackson writes.

Finally, a Policy Forum highlights the challenges of mountain communities and how science-informed policy could help in achieving more sustainable and resilient livelihoods for rural mountain dwellers worldwide. Mountain environments are home to nearly 1.1 billion people, many of whom are among the world’s poorest individuals. According to Yuka Makino and colleagues, more than half of mountain peoples face food insecurity and a lack of access to services and infrastructure, and their livelihoods – much like the mountain ecosystems they call home – are particularly vulnerable to natural disasters, climate change and unsustainable resource use. As such, identifying ways to protect and conserve mountain ecosystems while enabling mountain communities to improve their livelihoods is a key part in achieving the United Nations’ Sustainable Development Goals. Makino and colleagues highlight several partnerships, including the Mountain Partnership, a voluntary alliance of 60 governments, 16 intergovernmental organizations and nearly 300 major groups, working with the U.N. to achieve these goals. The authors demonstrate how scientific research plays a crucial role in developing effective policy towards these efforts.

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