Vegetation dynamics drive the evolution of soil aggregate stability during the first 14,000 years of soil development in the Swiss alps

Konrad Greinwald,Victoria Kolodziej,Fabian Maier,Ludwig Treuter,Florian Lustenberger,Michael Scherer-Lorenzen,Alessandra Musso,Tobias Gebauer

doi:10.5194/egusphere-egu21-10960

Abstract

&lt;p&gt;&lt;strong&gt;Aims:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;The stability of hillslopes is an essential ecosystem service, especially in alpine regions with soils prone to erosion. One key variable controlling hillslope stability is soil aggregate stability. However, there is comparatively little knowledge about how vegetation dynamics affect soil aggregate stability during landscape evolution.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;We quantified soil aggregate stability by determining the Aggregate Stability Coefficient (ASC), which was developed for stone-rich soils. To reveal how hillslope aging and corresponding changes in vegetation affect the evolution of ASC, we measured plant cover, diversity, and root traits along two chronosequences in the Swiss Alps.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;We found a significant positive effect of vegetation cover and diversity on ASC that was mediated via root traits. These relationships, however, developed in a time-depended manner: At young terrain ages, above- and belowground vegetation characteristics had a stronger effect on aggregate stability than species diversity, whereas these relationships were weaker at older stages.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Our findings highlight the importance of vegetation dynamics for the evolution of aggregate stability and enhance our understanding of processes linked to hillslope stabilization, which is a key priority to avoid further soil degradation and connected risks to human safety in alpine areas.&lt;/p&gt;

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