From the Cover: Strategic protection of landslide vulnerable mountains for biodiversity conservation under land-cover and climate change impacts

Natural disasters impose huge uncertainty and loss to human lives and economic activities. Landslides are one disaster that has become more prevalent because of anthropogenic disturbances, such as land-cover changes, land degradation, and expansion of infrastructure. These are further exacerbated by more extreme precipitation due to climate change, which is predicted to trigger more landslides and threaten sustainable development in vulnerable regions. Although biodiversity conservation and development are often regarded as having a trade-off relationship, here we present a global analysis of the area with co-benefits, where conservation through expanding protection and reducing deforestation can not only benefit biodiversity but also reduce landslide risks to human society. High overlap exists between landslide susceptibility and areas of endemism for mammals, birds, and amphibians, which are mostly concentrated in mountain regions. We identified 247 mountain ranges as areas with high vulnerability, having both exceptional biodiversity and landslide risks, accounting for 25.8% of the global mountainous areas. Another 31 biodiverse mountains are classified as future vulnerable mountains as they face increasing landslide risks because of predicted climate change and deforestation. None of these 278 mountains reach the Aichi Target 11 of 17% coverage by protected areas. Of the 278 mountains, 52 need immediate actions because of high vulnerability, severe threats from future deforestation and precipitation extremes, low protection, and high-population density and anthropogenic activities. These actions include protected area expansion, forest conservation, and restoration where it could be a cost-effective way to reduce the risks of landslides.

Land-cover/land-use changes, such as deforestation, agriculture expansion, and urbanization, are among the biggest drivers of biodiversity loss (1–3). These changes not only result in the decline of wildlife populations and fragmentation of habitats, but they also increase environmental risks, such as erosion of fertile soil and increases in avalanches, landslides, and flooding, especially in mountainous areas (4, 5). Landslides are one of the most prevalent natural hazards and are caused by changes in slope stability resulting from undercutting, changes in water saturation, or loss of woody vegetation (6). They have become more frequent because of anthropogenic activities and land-cover/land-use changes (7–9). Deforestation, infrastructure construction, and mining triggered about 16% of fatal landslides from 2004 to 2016 (10). Landslides cause direct and indirect damages worth billions of dollars each year across the world, contributing to 17% of the fatalities due to natural hazards (11). From 2006 to 2015, landslides alone accounted for 27.6% of the geological disasters worldwide and caused casualties of 9,477 people, threatening the livelihood of local communities (12).While land-cover changes exacerbate the conditions for landslide activities, precipitation is the primary trigger for landslides; one expected to increase in importance under climate change (13, 14). Either high-intensity, short-duration rainfall or prolonged rain at relatively low intensities can trigger landslides, creating a rainfall intensity–duration relationship for identifying possible areas of risk (15). Both model studies and historical records show an increase in precipitation extremes, such as heavy rainfall, flooding, and droughts with climate warming due to increases in the saturation vapor pressure of water (16–19). Consequently, the total precipitation from extreme events doubles per degree of warming, mainly because of increasing event frequencies (19). With this greater frequency and magnitude of heavy precipitation (20), landslides are expected to increase (21). For example, High Mountain Asia is predicted to experience a 30 to 70% increase in landslide activity because of the intensification of precipitation extremes (22). This geohazard poses one of the greatest threats of climate change to human safety and development with potentially huge economic losses (14).It is crucial to understand the relationship between environmental risks, biodiversity, and the potential for sustainable development. This is true especially for mountain communities, where many people are in poverty and have low resilience and adaptive capacity (6, 22–24). About 24% of the global land area is mountains with 12% of the world’s population (25). Local communities directly depend on mountainous resources for their livelihoods and well-being (26). Residents in mountain areas are among the most economically vulnerable populations because of inaccessibility to markets and high risks from natural disasters, such as earthquakes, flash floods, and the impacts of climate change (25). However, the common development pattern relies on land-use changes and infrastructure building, which could pose higher environmental risks in mountainous areas than in lowland regions. For example, the expansion of road networks degrades the slope stability and further increases the susceptibility to landslides (27–29).Mountain building driven by plate tectonics and volcanism provokes many geological disasters, including earthquakes, landslides, and volcanic movements (5, 30), but it also creates the landscape and climatic variations that drive species diversification. Mountains harbor an exceptionally large portion of the world’s biodiversity, including more than 85% of the world’s amphibian, bird, and mammal species (31). The interaction between speciation, coexistence, and persistence of species has resulted in high-species richness and endemism in most mountains, especially in the tropics (31). Nonetheless, habitat loss and degradation continue to threaten biodiversity in mountain regions, with increasing anthropogenic activities such as logging, livestock grazing, and agriculture expansion with a higher rate of land abandonment than lowland areas (32). Instead of trade-offs between conservation and development (33–35), we suggest that, with careful conservation planning and priority setting, a compatible outcome can be achieved. We identify vulnerable mountain regions for conservation that have both high biodiversity and landslide susceptibility. Since future landslide activity is expected to increase in areas with 1) increased deforestation and 2) increased regional precipitation due to climate change (36, 37), we also identified emerging vulnerable mountains in the future as priorities for conservation using land-use projections and climate scenarios. The emerging strategy of nature-based solutions (NBS) promotes nature as the means for providing solutions to societal challenges (38, 39). Here, we present a potential NBS and identify key areas with the greatest potential to reduce landslide risks while also protecting biodiversity through expanding protected areas, reducing deforestation, and restoring forests.