Pioneer biocrust communities prevent soil erosion in temperate forests after disturbances

Abstract

Abstract. Soil erosion continues to be one of the most serious environmental problems of our time and is exacerbated by progressive climate change. Until now, forests have been considered an ideal erosion control. However, even minor disturbances of the forest floor, for example, from heavy vehicles used for timber harvesting, can cause substantial sediment transport. An important countermeasure is the quick restoration of the uncovered soil surface by vegetation. To date, very little attention has been paid to the development of nonvascular plants, such as bryophytes, in disturbed areas of temperate forests and their impact on soil erosion. This study examined the natural succession of pioneer vegetation in skid trails on four soil substrates in a central European temperate forest and investigated their influence on soil erosion. For this purpose, rainfall simulations were conducted on small-scale runoff plots, and vegetation was continuously surveyed during the same period, primarily to map the development of bryophytes and the occurrence of biological soil crusts (biocrusts). Biocrusts appeared immediately after disturbance, consisting primarily of bryophyte protonemata and cyanobacteria as well as coccoid and filamentous algae that lost their biocrust characteristics as succession progressed. They were present from April to July 2019, with a particular expression in the skid trail that was on shale clay (Psilonotenton Formation) and silty clay loam substrate. In general, skid trails on clayey substrates showed considerably higher bryophyte cover and species richness. Although bryophytes were subsequently overtopped by vascular plants, they managed to coexist until their growth was restricted due to leaf litter fall. Brachythecium rutabulum and Oxyrrhynchium hians were the most important and persistent pioneer bryophyte species, while Dicranella schreberiana and Pohlia lutescens were volatile and quickly disappeared after spreading in the summer. Sediment discharge was 22 times higher on disturbed bare soil compared with undisturbed forest soil and showed the largest sediment removal in the wheel tracks. Counteracting this, soil erosion decreased with the recovery of surface vegetation and was particularly reduced with growing pioneer biocrusts in summer, but it again increased in winter, when vascular vegetation became dominant. This leads to the conclusion that the role of bryophyte-dominated biocrusts in forests has been underestimated so far, and they can contribute more to soil conservation at specific times of succession than vascular plants.

Effect of crevice density on biological soil crust development on rock cut slope in mountainous regions, Sichuan, China

“…More importantly, BSCs may capture dust and fine soils in the surrounding environment (Belnap et al 2001;Belnap 2010;Lu et al 2022a;Peer et al 2022;Wu et al 2005;Zubiri et al 2022). Additionally, BSC development should be beneficial for soil accumulation against water and wind erosion (Gall et al 2022;Guo et al 2022;Kheirfam and Roohi 2022;Lu et al 2022a). Polysaccharides secreted by BSCs can enhance the adherence of soil particles to each other, which in turn increases the soil stability and forms a dense layer for the surface to protect the soil from external forces (Mager and Thomas 2011;Margolis et al 2022;Lu et al 2022a;Nyenda et al 2019;Zhang et al 2002).…”

“…BSCs are early and fast pioneer colonizers of degraded and harsh environments, especially in strongly disturbed areas where vascular plant development is less likely to occur (Bowker 2007;Bu et al 2013). BSCs are widely considered as important ecosystem restorers (Bowker 2007;Bowker et al 2010;Karimi et al 2022;Lu et al2022a) due to the functional roles which BSCs play in natural ecosystems (Concostrina et al 2019), such as soil microorganism activity and diversity improvement (Tian et al 2022a;Wang et al 2022a, b), soil water storage (Chamizo et al 2013;Gong et al 2022;Lu et al 2022b;Belnap et al 2016), soil fertility improvement (Belnap et al 2016;Bowker 2007;Chamizo et al 2012;Deng et al 2020;Elbert et al 2009;Gao et al 2018;Giora et al 2015;Karimi et al 2022;Nyenda et al 2019;Tian et al 2022b;Wang et al 2022b;Zhang et al 2005a;Zhang et al 2022;Zubiri et al 2022), soil stability and physical structure enhancement (Gall et al 2022;Hu et al 2002;Karimi1 et al 2022;Mager and Thomas 2011), soil erosion alleviation (Chamizo et al 2013(Chamizo et al , 2019Gall et al 2022;Guo et al 2022;Kheirfam and Roohi 2022), and facilitating or inhibiting vascular plant establishment and growth…”

Short communication: Concentrated impacts by tree canopy drips: hotspots of soil erosion in forests

“…Therefore, forest can be seen as one of the most effective land use types to mitigate soil losses (Pimentel and Burgess, 2013). However, disturbance of forest vegetation may lead to significant punctual (Gall et al, 2022;Geißler et al, 2010) and areal (Safari et al, 2016;Seitz et al, 2016;Zemke et al, 2016) erosion events that can by far exceed sustainable erosion rates (Deng et al 2023). Important examples have been described globally such as in Hungary (Misik and Kárász, 2022) and China (Yao et al, 2019).…”

Applying Convolutional Neural Network to Predict Soil Erosion: A Case Study of Coastal Areas

“…Currently, many ecological restoration projects (ERPs) have been implemented, including soil improvement, afforestation, and grass planting, to reduce soil erosion. Among them, plantation forest is a typical ecological restoration plan [7,8]. Different from natural forests, plantation forests have simple structures, poor understory vegetation, and poor ecological stability [9][10][11], so their soil retention capacity is relatively weak.…”