Fernandez-Mendoza, F. | bioRxiv Science

bioRxiv2023

Biodiversity in mountain soils above the treeline

Despite the importance of healthy soils for human livelihood, wellbeing, and safety, current gaps in our knowledge and understanding of biodiversity in soil are numerous, undermining conservation efforts. These gaps are particularly wide in mountain regions where healthy soils are especially important for human safety and yet evidence is accumulating of ongoing degradation, posing significant threats to ecosystem functioning and human settlements. To analyse these gaps in detail, we synthesise current research on the global diversity of microorganisms, cryptogams, and invertebrates in mountain soils above the treeline. This synthesis is based on a semi-quantitative survey of the literature and an expert-based analysis. Our work reveals not only deficiencies in geographic cover but also significant gaps in taxonomic coverage, particularly among soil protists and invertebrates, and a lack of (functional and ecological) description of the uncultivated majority of prokaryotes, fungi, and protists. We subsequently build on this overview to highlight opportunities for research on mountain soils as systems of co-occurring species that interact in complex environmental matrices to fulfil critical functions and make essential contributions to life on land. Closing gaps in biodiversity research in mountain soil is crucial to enhance our understanding and to promote laws and guidelines advancing international soil biodiversity conservation targets in mountains. Addressing sparse and biased data, recognizing the impact of environmental changes on mountain ecosystems, and advocating dedicated policies are essential strategies to safeguard mountain soils and their biodiversity. GLOSSARY O_TBL View this table: org.highwire.dtl.DTLVardef@16682fdorg.highwire.dtl.DTLVardef@121b9feorg.highwire.dtl.DTLVardef@139eadeorg.highwire.dtl.DTLVardef@16abd74org.highwire.dtl.DTLVardef@bc3da9_HPS_FORMAT_FIGEXP M_TBL C_TBL

ecology↗

bioRxiv2023

Introgressive descent and hypersexuality drive the evolution of sexual parasitism and morphological reduction in a fungal species complex.

Taxonomists consider species as discrete units of biological organization, which are subject to a continuous process of evolutionary change and are connected through their shared ancestry. However, the continuous nature of evolutionary change is difficult to reconcile with the discrete outcome of speciation, especially where species boundaries are permeable. A good example of this inconsistency is the lichen genus Pyrenodesmia, which shows a high morphologic and genetic diversity that that defies systematization by taxonomic or phylogenetic methods. Here we show that hybridization explains the presence of discordant morphs and that European species are interconnected through cross-mating in a single reproductive network, a syngameon, despite which species remain largely distinct and distinguishable. Whole genome data reflect the important role played by genome defense mechanisms in the genomic stabilization of fungal hybrids. The recurrence of Repeat Induced Point mutations (RIP) shapes genomes with islands of suppressed recombination and loss of gene content, which in turn generates a feedback loop reinforcing the lack of reproductive isolation through the loss of heterokaryon incompatibility and a tendency towards morphological reduction.

evolutionary biology↗