Expanding the mutualistic niche: parallel symbiont turnover along climatic gradients

  • Keystone mutualisms, such as corals, lichens or mycorrhizae, sustain fundamental ecosystem functions. Range dynamics of these symbioses are, however, inherently difficult to predict because host species may switch between different symbiont partners in different environments, thereby altering the range of the mutualism as a functional unit. Biogeographic models of mutualisms thus have to consider both the ecological amplitudes of various symbiont partners and the abiotic conditions that trigger symbiont replacement. To address this challenge, we here investigate 'symbiont turnover zones'--defined as demarcated regions where symbiont replacement is most likely to occur, as indicated by overlapping abundances of symbiont ecotypes. Mapping the distribution of algal symbionts from two species of lichen-forming fungi along four independent altitudinal gradients, we detected an abrupt and consistent β-diversity turnover suggesting parallel niche partitioning. Modelling contrasting environmental response functions obtained from latitudinal distributions of algal ecotypes consistently predicted a confined altitudinal turnover zone. In all gradients this symbiont turnover zone is characterized by approximately 12°C average annual temperature and approximately 5°C mean temperature of the coldest quarter, marking the transition from Mediterranean to cool temperate bioregions. Integrating the conditions of symbiont turnover into biogeographic models of mutualisms is an important step towards a comprehensive understanding of biodiversity dynamics under ongoing environmental change.

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Author:Gregor RolshausenORCiDGND, Uwe Hallman, Francesco Dal GrandeORCiD, Jürgen OtteORCiDGND, Kerry KnudsenORCiD, Imke SchmittORCiDGND
URN:urn:nbn:de:hebis:30:3-825456
DOI:https://doi.org/10.1098/rspb.2019.2311
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/32228406
Parent Title (English):Proceedings of the Royal Society of London. Series B, Biological sciences
Publisher:The Royal Society
Place of publication:London
Document Type:Article
Language:English
Date of Publication (online):2020/04/01
Date of first Publication:2020/04/01
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2024/05/17
Tag:altitude-for-latitude; beta-diversity turnover; facilitation; lichen symbiosis; mutualist-mediated effects; range predictions
Volume:287
Issue:20192311
Article Number:20192311
Page Number:9
HeBIS-PPN:520349067
Institutes:Biowissenschaften / Biowissenschaften
Angeschlossene und kooperierende Institutionen / Senckenbergische Naturforschende Gesellschaft
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 4.0