Microclimatic effects on alpine plant communities and flower-visitor interactions

Abstract

High-alpine ecosystems are commonly assumed to be particularly endangered by climate warming. Recent research, however, suggests that the heterogeneous topography of alpine landscapes provide microclimatic niches for alpine plants (i.e. soil temperatures that support the establishment and reproduction of species). Whether the microclimatic heterogeneity also affects diversity or species interactions on higher trophic levels remains unknown. Here we show that variation in mean seasonal soil temperature within an alpine pasture is within the same range as in plots differing in nearly 500 m in elevation. This pronounced heterogeneity of soil temperature among plots affected the spatial distribution of flowering plant species in our study area with a higher plant richness and cover in warmer plots. This increased plant productivity in warmer plots positively affected richness of flower visitor taxa as well as interaction frequency. Additionally, flower-visitor networks were more generalized in plots with higher plant cover. These results suggest that soil temperature directly affects plant diversity and productivity and indirectly affects network stability. The strong effect of heterogeneous soil temperature on plant communities and their interaction partners may also mitigate climate warming impacts by enabling plants to track their suitable temperature niches within a confined area.Alpine ecosystems are particularly sensitive to climate change as scenarios predict severe warming for high elevations in alpine regions 1 . Therefore, cold adapted alpine plant species are threatened by increased temperatures 2,3 . Recently, considerable work has described and tested possible scenarios for responses of alpine plants to climate change 4,5 . Regional plant diversity in alpine habitats is expected to change as a result of climate warming due to shifts in temperature niches and species' distributions, which may result in increased competition due to shifts of plants' distributions to higher elevations and consequently the assembly of new communities 6-8 . Plant species richness and composition affects organisms and processes across trophic levels 9 . For instance, the diversities of plants and their flower visitors have been shown to be particularly related due to insect-specific preferences for certain plant species 10-12 . Therefore, a change in plant abundance and distribution and shifts in phenologies due to rising temperatures potentially have negative effects on other trophic levels, in particular on flower visiting insects 13,14 and thus impact community structure and put ecosystem functions at risk 15 .Among the main drivers of (alpine) plant diversity are climatic conditions and biotic interactions [16][17][18][19] . However, plant community composition and diversity are not only shaped by average environmental and climatic conditions but also by local micro-abiotic filtering 20 . Specifically, soil temperatures, which in contrast to air temperatures are strongly shaped by the local topography and intake of solar r...

Elevation and aspect determine the differences in soil properties and plant species diversity on Himalayan mountain summits

“…Soil temperature was another important factor regulating the plant diversity on our studied summits, as reported in other studies as well (Gutiérrez‐Girón & Gavilán, 2010; Ohler, Lechleitner, & Junker, 2020; Winkler et al, 2016). It suggests that soil temperature plays an important role in shaping plant diversity in alpine ecosystems.…”

Mire microclimate: Groundwater buffers temperature in waterlogged versus dry soils

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Forest microclimates and climate change: Importance, drivers and future research agenda

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