Negative legacy effects of past forest use on plant diversity in semi-natural grasslands on ski slopes

Abstract

Over the past century, grassland and forest ecosystems globally have been heavily influenced by land use changes driven by diverse socioeconomic activities. Ski resorts are a modern land-use type associated with biodiversity loss in mountain ecosystems worldwide. Below the treeline, by contrast, some ski slopes have been shown to provide suboptimal semi-natural habitats for native grassland plants and animals, depending on specific construction and management practices. We compared environmental factors and grassland vegetation between two types of ski slopes in central Japan with different land-use histories: slopes constructed on old pastures (pasture slopes) and slopes constructed by clearing secondary forests or Larix kaempferi plantations established on abandoned pastures during the 1940s-1990s (forest slopes). We examined the effects of land use history and machine grading as well as other environmental factors on ski slope vegetation, including total species richness and the richness of native, endangered, and exotic plants, using a total of 108 plots of 2 m × 10 m. Compared to pasture slopes, forest slopes exhibited significantly lower richness of total plants and native grassland species, including endangered species. Forest slopes were more graded than pasture slopes, resulting in lower native and higher exotic grassland species richness. A significantly lower duration of direct sunlight on forest slopes than on pasture slopes possibly decreased endangered species diversity. The lower species richness on forest slopes may be partly caused by seed dispersal limitations. Our findings demonstrate that ski slopes have good potential to support numerous native grassland plant species, including endangered species, but this potential is significantly and negatively affected by forest use history and concomitant environmental changes. The conservation of semi-natural conditions on pasture slopes as habitats for native grassland species can be promoted through the maintenance of annual mowing practices, avoidance of machine grading, and wider ski courses.

Seed dispersal limitation causes negative legacy effect on restoration of grassland plant diversity on ski slopes

“…In regions with a history of different land use, it often takes decades for restored semi‐natural grasslands to regain their original species diversity and composition (Forey & Dutoit, 2012 ; Helm et al., 2019 ; Inoue et al., 2021 ; Yaida et al., 2022 ). Past human activities, such as afforestation, intensive fertilization and grazing, and land modification (e.g., grading, consolidation, and changes in topography) using heavy machinery, have altered soil characteristics and led to a degraded seed bank, thus having long‐term negative impacts on the recovery of the original plant composition of semi‐natural grasslands (Helm et al., 2019 ; Matsumura & Takeda, 2010 ; Roux‐Fouillet et al., 2011 ; Uchida & Ushimaru, 2014 ).…”

“…Past human activities, such as afforestation, intensive fertilization and grazing, and land modification (e.g., grading, consolidation, and changes in topography) using heavy machinery, have altered soil characteristics and led to a degraded seed bank, thus having long‐term negative impacts on the recovery of the original plant composition of semi‐natural grasslands (Helm et al., 2019 ; Matsumura & Takeda, 2010 ; Roux‐Fouillet et al., 2011 ; Uchida & Ushimaru, 2014 ). These long‐term negative impacts, known as “legacy effects,” occur in grassland restoration as well as forest restoration, though the detailed underlying mechanisms are not yet fully understood (Hermy & Verheyen, 2007 ; Yaida et al., 2022 ; Yang et al., 2017 ).…”

“…Current land use in ski resort management below the treeline involves maintaining semi‐natural grasslands as ski slopes through annual mowing (Tsuyuzaki, 2002 ; Yaida et al., 2019 ). Ski slopes that were originally created on semi‐natural grasslands, such as past pastures (hereafter we refer to them as pasture ski slopes), hold high potential as alternative habitats for numerous native grassland plant species, including endangered plant species (Inoue et al., 2021 ; Wipf et al., 2005 ; Yaida et al., 2019 , 2022 ). The grassland species at risk of extinction have been lost over the past few decades in Japan like in countries across Europe (Török & Dengler, 2018 ; Ushimaru et al., 2018 ).…”

“…The grassland species at risk of extinction have been lost over the past few decades in Japan like in countries across Europe (Török & Dengler, 2018 ; Ushimaru et al., 2018 ). In contrast, most ski slopes constructed by clearing secondary forests or conifer plantations established on abandoned pastures and mechanically leveling the land (hereafter we refer to them as forest ski slopes) have been known to exhibit lower plant diversity than pasture ski slopes, even a few to several decades after their construction (Inoue et al., 2021 ; Yaida et al., 2022 ). This illustrates another example of the “legacy effect” that hinders the recovery of diverse native grassland plants.…”

“…This study compared the vegetation of forest and pasture ski slopes in the Sugadaira and Minenohara Plateaus, central Japan: Pasture slopes that have been subjected to successive grassland management for at least 100 years and potentially approximately 4000 years (Yamanoi, 1996 ), and forest slopes constructed by clearing secondary forests and Larix plantation in the 1900s and built from the 1940s to the 2000s (Yaida et al., 2022 ). We surveyed multiple sites with different construction times and spatial positions relative to pasture slopes for forest ski slopes.…”