TY - JOUR

T1 - High nitrogen-fixing rates associated with ground-covering mosses in a tropical mountain cloud forest will decrease drastically in a future climate

AU - Permin, Aya

AU - Horwath, Aline B.

AU - Metcalfe, Daniel B.

AU - Priemé, Anders

AU - Rousk, Kathrin

N1 - CENPERMOA[2022] Publisher Copyright: © 2022 The Authors. Functional Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

PY - 2022

Y1 - 2022

N2 - Tropical mountain cloud forests (TMCF) harbour a high bryophyte (mosses and liverworts) biomass and diversity. Furthermore, the high air humidity makes these forests well suited for bryophyte-associated nitrogen (N2) fixation by cyanobacteria, providing a potentially important source of N input to the ecosystem. However, few studies have assessed bryophyte-associated N input in these ecosystems, and these have focused on epiphytic bryophytes, whereas abundant ground-covering bryophytes have not been included. In this study, we quantified N2 fixation rates associated with bryophytes, focusing on ground-covering mosses in a neotropical mountain cloud forest. Furthermore, we identified the effects of climate change (higher temperature 10 vs. 20° and lower bryophyte moisture level 50% vs. 100%) on N2 fixation across bryophyte species and groups (mosses and liverworts). Nitrogen fixation rates associated with ground-covering moss species were up to 2 kg N ha−1 year−1, which is comparable to other N inputs (e.g. N deposition) in tropical cloud forests. Furthermore, changes in temperature showed little effect on N2 fixation, but low moisture levels significantly suppressed N2 fixation activity. We found low N2 fixation activity associated with the investigated liverworts. Our results demonstrate the importance of ground-covering, moss-associated N2 fixation as a N source in tropical cloud forests and suggest that predicted future declines in precipitation in these systems will reduce N inputs from bryophyte-associated cyanobacteria. Read the free Plain Language Summary for this article on the Journal blog.

AB - Tropical mountain cloud forests (TMCF) harbour a high bryophyte (mosses and liverworts) biomass and diversity. Furthermore, the high air humidity makes these forests well suited for bryophyte-associated nitrogen (N2) fixation by cyanobacteria, providing a potentially important source of N input to the ecosystem. However, few studies have assessed bryophyte-associated N input in these ecosystems, and these have focused on epiphytic bryophytes, whereas abundant ground-covering bryophytes have not been included. In this study, we quantified N2 fixation rates associated with bryophytes, focusing on ground-covering mosses in a neotropical mountain cloud forest. Furthermore, we identified the effects of climate change (higher temperature 10 vs. 20° and lower bryophyte moisture level 50% vs. 100%) on N2 fixation across bryophyte species and groups (mosses and liverworts). Nitrogen fixation rates associated with ground-covering moss species were up to 2 kg N ha−1 year−1, which is comparable to other N inputs (e.g. N deposition) in tropical cloud forests. Furthermore, changes in temperature showed little effect on N2 fixation, but low moisture levels significantly suppressed N2 fixation activity. We found low N2 fixation activity associated with the investigated liverworts. Our results demonstrate the importance of ground-covering, moss-associated N2 fixation as a N source in tropical cloud forests and suggest that predicted future declines in precipitation in these systems will reduce N inputs from bryophyte-associated cyanobacteria. Read the free Plain Language Summary for this article on the Journal blog.

KW - bryophytes

KW - climate change

KW - cyanobacteria

KW - liverworts

KW - mosses

KW - nitrogen fixation

KW - nitrogen input

KW - tropical mountain cloud forest

U2 - 10.1111/1365-2435.14088

DO - 10.1111/1365-2435.14088

M3 - Journal article

AN - SCOPUS:85130961961

VL - 36

SP - 1772

EP - 1781

JO - Functional Ecology

JF - Functional Ecology

SN - 0269-8463

IS - 7

ER -