title: Bryophyte-cyanobacteria associations during primary succession in recently Deglaciated areas of Tierra del Fuego (Chile).
abstract: Bryophyte establishment represents a positive feedback process that enhances soil development in newly exposed terrain. Further, biological nitrogen (N) fixation by cyanobacteria in association with mosses can be an important supply of N to terrestrial ecosystems, however the role of these associations during post-glacial primary succession is not yet fully understood. Here, we analyzed chronosequences in front of two receding glaciers with contrasting climatic conditions (wetter vs drier) at Cordillera Darwin (Tierra del Fuego) and found that most mosses had the capacity to support an epiphytic flora of cyanobacteria and exhibited high rates of N2 fixation. Pioneer moss-cyanobacteria associations showed the highest N2 fixation rates (4.60 and 4.96 µg N g-1 bryo. d-1) very early after glacier retreat (4 and 7 years) which may help accelerate soil development under wetter conditions. In drier climate, N2 fixation on bryophyte-cyanobacteria associations was also high (0.94 and 1.42 µg N g-1 bryo. d-1) but peaked at intermediate-aged sites (26 and 66 years). N2 fixation capacity on bryophytes was primarily driven by epiphytic cyanobacteria abundance rather than community composition. Most liverworts showed low colonization and N2 fixation rates, and mosses did not exhibit consistent differences across life forms and habitat (saxicolous vs terricolous). We also found a clear relationship between cyanobacteria genera and the stages of ecological succession, but no relationship was found with host species identity. Glacier forelands in Tierra del Fuego show fast rates of soil transformation which imply large quantities of N inputs. Our results highlight the potential contribution of bryophyte-cyanobacteria associations to N accumulation during post-glacial primary succession and further describe the factors that drive N2-fixation rates in post-glacial areas with very low N deposition.
authors.affiliation: Dept. de Biología Vegetal II, Universidad Complutense de Madrid, Madrid, Spain; School of Environment Natural Resources and Geography, Bangor University, Bangor, Wales, United Kingdom.
authors.forename: María
authors.initials: M
authors.lastname: Arróniz-Crespo
authors.affiliation: Dept. de Biología Ambiental, Museo Nacional de Ciencias Naturales, MNCN-CSIC, Madrid, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Pérez-Ortega
authors.affiliation: Dept. de Biología Ambiental, Museo Nacional de Ciencias Naturales, MNCN-CSIC, Madrid, Spain.
authors.forename: Asunción
authors.initials: A
authors.lastname: De Los Ríos
authors.affiliation: Dept. de Biología Vegetal II, Universidad Complutense de Madrid, Madrid, Spain; Biological Sciences, Waikato University, Hamilton, New Zealand.
authors.forename: T G Allan
authors.initials: TG
authors.lastname: Green
authors.affiliation: Dept. de Biogeografía y Cambio Global, Museo Nacional de Ciencias Naturales, Madrid, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Ochoa-Hueso
authors.affiliation: Departamento Edafología, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Miguel Ángel
authors.initials: MÁ
authors.lastname: Casermeiro
authors.affiliation: Departamento Edafología, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: de la Cruz
authors.affiliation: Dept. de Biología Vegetal II, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Pintado
authors.affiliation: Departamento Geografía Física, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Palacios
authors.affiliation: Sub-Antarctic Biocultural Conservation Program, University of North Texas, Denton, Texas, United States of America; Institute of Ecology and Biodiversity, Universidad de Magallanes, Puerto Williams, Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rozzi
authors.affiliation: School of Biological Sciences, Bangor University, Bangor, Wales, United Kingdom.
authors.forename: Niklas
authors.initials: N
authors.lastname: Tysklind
authors.affiliation: Dept. de Biología Vegetal II, Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: Leopoldo G
authors.initials: LG
authors.lastname: Sancho
mesh_terms: D044002:Bryophyta / Q000502:physiology*; D002677:Chile; D000458:Cyanobacteria / Q000502:physiology*; D017753:Ecosystem; D046448:Ice Cover