Biological soil crust and vascular plant interactions in Western Myall (Acacia papyrocarpa) open woodland in South Australia

Abstract

Aim: Biological soil crust (BSC) is a key component of arid environments and plays a major role in determining ecological structure and function. Our research aim was to examine several mechanisms that contribute to BSC-plant interactions at species and community levels, to increase our understanding of plant community dynamics.Location: Yellabinna Regional Reserve, South Australia (30°50′17.99″ S, 132°12′10.37″ E). Methods:We used seed extraction techniques to examine soil seed banks beneath patches with and without BSC, and field and glasshouse experiments to study the effects of crust presence and disturbance on seedling emergence and survival. We also explored the influence of chemical leachates from BSC on seed germination. Results:Biological soil crust plays a pivotal role in influencing spatial patterns in soil seed bank composition. Our results showed less propagules accumulate in soils beneath crust when compared with patches without crust, and that propagule size is a contributing factor to determining their distribution between patch types. We found that late-stage BSC physically inhibited seedling emergence, which increased when the BSC was disturbed in field experiments. Low seedling survivorship in both patch types suggests that although BSC may suppress recruitment in favourable years, it is low precipitation levels that have the over-riding impact on recruitment success.Finally, leachates from late-stage BSC were found to inhibit germination in three annual plant species, whilst early-stage BSC accelerated germination in one annual plant. This clearly shows that leachate effects on seed germination vary according to plant species and crust successional stage. Conclusion:Overall, we identified several mechanisms through which BSC has complex effects on the annual and short-lived perennial plant guilds of arid lands. These mechanisms contribute to species diversity through the creation of spatial heterogeneity in soil seed bank structure and emergence opportunities. K E Y W O R D S allelopathy, arid ecology, biological soil crust, chemical leachates, chenopod shrubland, microphytic crust, plant community structure, seed germination, seedling emergence, soil seed banks | 757 Additional supporting information may be found online in the Supporting Information section at the end of the article. Appendix S1. Nomenclature used to classify BSC types and successional stages, and images of surface types examined in this study Appendix S2. Summary of treatments used to investigate the effects of BSC leachates on seed germination, and seed descriptions and their pre-treatments Appendix S3. Mean number of seedlings per taxon recorded in field quadrats and cores Appendix S4. Patterns of seedling emergence and survival recorded in field quadrats over a nine month period How to cite this article: Steggles EK, Facelli JM, Ainsley PJ, Pound LM. Biological soil crust and vascular plant interactions in Western Myall (Acacia papyrocarpa) open woodland in South Australia. J Veg Sci. 2019;30:756-764.

Effects of Biological Crust on Soil Properties under Different Karst Rocky Desertification Habitats

“…In the results of this experiment, except for pH value, the correlation of other physical and chemical properties between crust and subsoil is significant ( Table 2, Table 3), indicating that the change law of physicochemical properties of crust and subsoil is synchronous. A comparison of the values of soil vertical profile shows that the nutrient content in the crust and 0-5cm soil layer of BSCs is significantly higher than that of 5-10cm soil layer, decreasing with the depth of the crust layer, which is consistent with the conclusions obtained by Emma K et al in southern Australia, Researchers in Gurbantunggut Desert area in Xinjiang, and in Loess Plateau of China [26][27][28]. Note: 1.…”