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Abstract:
Biological soil crusts are ecologically important communities in areas where vascular plant coverage is low, and their presence
is often vital in prevention of soil erosion. Despite recurrent threats to biological soil crusts across different environments,
their recovery after disturbance has been little studied. We therefore established experiments across a latitudinal gradient
in Europe, from Öland, Sweden in the north, to Gössenheim, Germany and Hochtor, Austria, to Almeria, Spain in the south,
spanning over 20
∘
latitude and 2,300 m in altitude, and including natural and semi-natural sites. At each site 10 (1 × 1m)paired
plots were constructed where the biological soil crusts were either completely removed, or left intact. Over a 2-year period
(2012–2014) the plots were regularly sampled to assess functional group recovery (cyanobacteria, algae, lichens, bryophytes,
vascular plants), soil stability, and chlorophyll, carbon, and nutrient contents. Cyanobacterial assemblages were examined
by denaturing gradient gel electrophoresis, a technique used to detect DNA in environmental samples. The results indicated
that recovery was site dependent, suggesting that physical and climatic parameters play a major role in biological soil crust
recovery. This conclusion is supported by the results of the soil properties, which were found to differ between sites, although
they did not show meaningful recovery over the study period. Although 2 years was insufcient for pronounced biological
soil crust recovery, this study documents changes over the initial recovery period, suggests management practices for future
projects, and recommends proxies for measuring recovery over time.
