The Qinghai-Tibet Plateau (QTP), the “Third Pole of the Earth,” boasts the most complex, diverse, and unique ecosystem in the world. From tropical vegetation on the southern slopes of the Himalayas to alpine subnival ecosystems, and from humid forests in the east to arid Gobi or desert vegetation in the west, the QTP encompasses nearly all the ecosystem types found in the Northern Hemisphere (The Comprehensive Scientific Expedition to Qinghai-Xizang Plateau, Academia Sinica, 1988). Biodiversity on the QTP is also among the richest and most complex in the world, with its southern part within the biodiversity hotspot of Himalaya, while its eastern and southeastern parts lie within the hotspot of the Mountains of Southwest China; the northwestern region borders the hotspot of the Mountains of Central Asia, and the southeastern side connects with the Indo-Burma hotspot (Myers et al., 2000). Here, different floristic elements meet, resulting in relatively complete phylogenetic lineages of plants. Coupled with the diversification of plant diversity on the plateau, this has led to the emergence of numerous endemic species and unique adaptive mechanisms (Wen et al., 2014). As a result, the region boasts exceptionally rich plant diversity, with 12,058 species of seed plants belonging to 1620 genera, of which 38.2% species are endemic (Zhang et al., 2016). Additionally, the QTP hosts the world’s richest alpine periglacial flora, comprising more than 1500 species from 240 genera, with an endemism rate as high as 73% (Sun, 2023). Recent studies have shown that the QTP also contains an important part of China’s genetic diversity and glacial refugia (Deng et al., 2019). Not only are there abundant plant resources here, but there are also important genetic resources that provide resistance to stresses such as cold, drought, and radiation, which have potential applications for agriculture (Xu et al., 2014). However, most species grow in specialized habitats on the plateau, with a narrow distribution range, and are highly susceptible to environmental changes and human activities.

A significant increase in human activity has had a tremendous impact on the Earth’s environment. These recent environmental changes have led researchers to name our current human-dominated epoch the Anthropocene (Zalasiewicz et al., 2011). Although there is currently no consensus on the starting point of the Anthropocene, significant impacts on Earth’s environment likely began after the Industrial Revolution, around 1610 (Lewis and Maslin, 2015). Paleoanthropological studies indicate that human activities have existed on the QTP since prehistoric times, and can be traced back to the Last Glacial Maximum (Zhang and Li, 2002) or the early Holocene (Meyer et al., 2017). Recent research has reported that Denisovans inhabited the northeastern Tibet Plateau as early as 160,000 years ago (Chen et al., 2019). Around 3600 years ago, the introduction and utilization of cold-tolerant crops (e.g., barley) and domesticated animals (e.g., sheep) began in the region (Chen et al., 2015). However, the QTP occupies a vast land mass located at high elevations (with an average elevation of over 4000 m), where oxygen deficiency, low temperatures, strong ultraviolet radiation, and limited arable land make it generally unsuitable for human habitation. Thus, before Xizang’s rapid socio-economic development a half a century ago, human activity had minimal impact on plant diversity of the QTP.

More recently, the intensification of global warming has greatly impacted plant diversity in high-elevation regions of the QTP. Research on precipitation changes across the QTP have revealed that annual average precipitation increased at a rate of 2.54 mm per decade from 1982 to 2000, indicating an overall trend toward a wetter climate (Zhong et al., 2011; Yang et al., 2014). Concurrently, significant temperature rises, particularly at higher elevations, have accelerated glacial and snow cover changes (Yao et al., 2019a); in turn, climate warming, increased rainfall, and extended growing seasons on the QTP have increased vegetation productivity (Huang et al., 2019; Ni, 2000). Warmer temperatures have also increased the height and coverage of deciduous shrubs and herbs while reducing the coverage of cushion plants, mosses, and lichens (reviewed by Lu et al., 2025). Additionally, warmer temperatures have driven the upward shift of treelines, and the invasion of non-native species has progressively impacted ecosystems and biodiversity (reviewed by Lu et al., 2025; Chen et al., 2011; Yang et al., 2025).

Recent land-use practices, especially overgrazing, have degraded high-elevation grasslands (Liu et al., 2021; Wang et al., 2024). Overexploitation of plants has depleted resources, endangering many species and even causing local extinction (Su et al., 2017). Major construction projects continue to expand, including railways, highways, bridges, dams, and tunnels, as has urban expansion, which removes natural physical and ecological barriers, often causing changes in plant distribution patterns, modifying ecosystems, and interfering with wildlife migration corridors. Such disturbances also facilitate the unchecked spread of invasive species (Wang and Ding, 2024; Tan et al., 2024). Additionally, the widespread use of wire fencing across grasslands has severely impeded inter-population connectivity among animal species, further fragmenting habitats (Yao et al., 2019b; Sun et al., 2021).

Both climate change and human activities have exerted increasingly profound impacts on QTP plant diversity. This special section compiles research and reviews on changes in plant diversity across the QTP during the Anthropocene, with a focus on changes in plant diversity, treelines, forest ecosystems, plant products, periglacial plants, and species invasions.

Yang et al. (2025) summarize previous research to clarify how climate change and human activities affect plant diversity on the QTP, and further explore how this diversity feeds back on the functions of high-elevation ecosystems in the plateau and surrounding areas.

Miehe et al. (2025) review the paleoenvironmental records of the first transformation of forests into “alpine meadows” in the early Holocene and existing records of changes in the forest line transition zone in the region. The researchers note that the transformation of mountain forests on the QTP into “alpine meadows” is the largest such transformation in the world, and that this transformation may have been caused by the plateau’s transition to agriculture and animal husbandry at the beginning of the Anthropocene.

Zhang et al. (2025) investigated how climate warming has altered subalpine forest structure in southeastern Xizang. Analysis of 3145 forest inventory plots over a 4–5-year period revealed a shift from fir-spruce forests to pine and broadleaf forests since the early 1970s, mostly occurring between 1994 and 1998. These foundational changes in vegetation composition may profoundly impact ecosystem functions and services. These findings indicate that under moderate future warming broadleaf forests are likely to expand faster than evergreen conifers.

Analysis of a comprehensive dataset including all species of native and naturalized non-native vascular plants known to occur in the core part of the QTP led Qian and Deng (2025) to conclude that naturalized angiosperm species are phylogenetically clustered with respect to the species pool, including all native and naturalized angiosperm species on the QTP. According to their analysis, naturalized angiosperm species are a phylogenetically clustered subset of all angiosperm species on the QTP, regardless of whether the plateau as a whole or its constituent regions were considered.

Zhou et al. (2025) simulated climate warming conditions in a laboratory to determine the effects of warmer temperatures and associated changes in humidity and light on seed germination and seedling growth of the typical alpine cushion plant Arenaria oreophila. Their findings indicate that A. oreophila is highly sensitive to climate warming, which strongly limits its seedling establishment process. These findings suggest that future climate warming may pose risks to the persistence of A. oreophila by restricting the seedling recruitment process.

Zheng et al. (2025) used genetic and genomic data to identify factors that cause early bolting in the Tibetan turnip. Their findings indicate that the fundamental cause of early bolting in turnip is oilseed cross contamination caused by local agricultural practices.

Pan et al. (2025) found that moisture, not temperature, has the greatest impact on the productivity and species diversity of plants in alpine grasslands. This study provides a basis for predicting the trends in plant productivity and species diversity in response to climate change on the QTP.

Acknowledgments

Preparation of this paper was funded by Key Project of Regional Innovation and Development Joint Fund of National Natural Science Foundation of China (U23A20149); the Second Tibetan Plateau Scientific Expedition and Research (STEP) program (2019QZKK0502, 2024QZKK0200).

CRediT authorship contribution statement

Hang Sun: Conceptualization, Supervision, Funding acquisition, Writing-original draft, Writing-review & editing. Yongping Yang: Writing-original draft, Writing-review & editing. Weibang Sun: Writing-original draft, Writing-review & editing. Rong Li: Writing-original draft, Writing-review & editing. Tao Deng: Writing-original draft, Writing-review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors Hang Sun, Weibang Sun, Rong Li and Tao Deng are the Editorial Board Members for Plant Diversity and were not involved in the editorial review or the decision to publish this article.