Gain and loss: Human and environmental wellbeing – drivers of Kilimanjaro’s decreasing biodiversity

PLOS One | https://doi.org/10.1371/journal.pone.0334184 October 29, 2025 1 / 23 OPEN ACCESS Citation: Hemp A, Miyazawa M, Hurskainen P (2025) Gain and loss: Human and environmental wellbeing – drivers of Kilimanjaro's decreasing biodiversity. PLoS One 20(10): e0334184. https://doi.org/10.1371/ journal.pone.0334184 Editor: Mattias Gaglio, University of Ferrara, ITALY Received: June 13, 2025 Accepted: September 23, 2025 Published: October 29, 2025 Copyright: © 2025 Hemp et al . This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data availability statement: The data are deposited on https://doi.pangaea. de/10.1594/PANGAEA.942806,10.5281/zeno- do.13929135,10.5281/zenodo.13929113, and 10.5281/zenodo.13929084. Census data are available from National Bureau of Statistics, Dar es Salaam: National Bureau of Statistics RESEARCH ARTICLE Gain and loss: Human and environmental wellbeing – drivers of Kilimanjaro’s decreasing biodiversity Andreas Hemp 1,2,3*, Mieko Miyazawa4, Pekka Hurskainen 5,6 1 Department of Plant Systematics, University of Bayreuth, Bayreuth, Germany, 2 Waldkundeinstitut Eberswalde, Eberswalde, Germany, 3 Global Mountain Biodiversity Assessment, University of Bern, Bern, Switzerland, 4 Department of International Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan, 5 Finnish Environment Institute, Helsinki, Finland, 6 Department of

Geosciences and Geography, Earth Change Observation Laboratory, University of Helsinki, Helsinki, Finland * andreas.hemp@uni-bayreuth.de Abstract Tropical mountains such as Kilimanjaro are biodiversity hotspots providing ecosystem services for millions of people, but many are under great pressure. Effective policies to halt biodiversity loss require an understanding of which anthropogenic factors are the main direct causes. While previous research focused mainly on climate change and on the effects rather than the causes, we investigated the effects of multiple drivers on biodiversity. The focus is on floristic and vegetation diversity, as vegeta- tion is closely related to the diversity of other taxa and plays a fundamental role in ecosystem functioning. We show that land-use change caused by rapid population growth was the main direct driver on Kilimanjaro between 1911 and 2022, when 75% of natural species per km2 disappeared from the lower slopes. Climate change, on the other hand, had no apparent influence on the observed trends in biodiversity. The significant increase in traditional and diverse agroforestry and the establishment of protected areas show possibilities for mitigation. Kilimanjaro is thus an example of the challenges of global change, but also of the prospects and opportunities for other tropical regions. Introduction Globally, human population growth and increasing per-capita demands for natural resources and energy are escalating human impacts on nature [1]. These indirect

factors — such as economic development, institutions, and governance — contribute to biodiversity loss and influence direct anthropogenic drivers, which affect biodiver- sity at multiple levels (within species, between species, and across ecosystems) [2]. The most notable direct drivers include land-use change, climate change, natural resource exploitation, pollution, and invasive species [3]. Human well-being relies