Can bryophyte groups increase functional resolution in tundra ecosystems?

Signe Lett,Kristel Van Zuijlen,Kari Klanderud,Frida Keuper,Flemming Ekelund,Ingibjörg S Jónsdóttir,Esther Lévesque,Elisabeth J Cooper,Dagmar Egelkraut,Casper T Christiansen,Juha M Alatalo,Tatiana G Elumeeva,Kathrin Rousk,Alessandro Petraglia,Anne Tolvanen,Christian Rixen,Igor Volkov,Ellen Dorrepaal,Robert D Hollister,Vigdis Vandvik,Anders Michelsen,Michele Carbognani,Annika K Jägerbrand,Katlyn R Betway,Pascale Michel,Xin Liu,Simone I Lang,Johannes H C Cornelissen ,Irina I Volkova ,Sara Buscà ,Siri Vatsø Haugum ,Greg H.r Henry ,Bjorn J M Robroek ,Heinjo J During ,Nadia Soudzilovskaia ,Martin Alfons Mörsdorf ,Jeremy L May ,Antoine Becker‐Scarpitta ,Terry V Callaghan ,Agnieszka Marta Rzepczynska

doi:10.1139/as-2020-0057

Abstract

The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte function remains poorly resolved. Here, we explore how higher resolution of bryophyte functional diversity can be encouraged and implemented in tundra ecological studies. We briefly review previous bryophyte functional classifications and the roles of bryophytes in tundra ecosystems and their susceptibility to environmental change. Based on shoot morphology and colony organization, we then propose twelve easily distinguishable bryophyte functional groups. To illustrate how bryophyte functional groups can help elucidate variation in bryophyte effects and responses, we compiled existing data on water holding capacity, a key bryophyte trait. Although plant functional groups can mask potentially high interspecific and intraspecific variability, we found better separation of bryophyte functional group means compared with previous grouping systems regarding water holding capacity. This suggests that our bryophyte functional groups truly represent variation in the functional roles of bryophytes in tundra ecosystems. Lastly, we provide recommendations to improve the monitoring of bryophyte community changes in tundra study sites.

Highlights

In the Arctic, bryophytes represent 30% of all plant species (Walker and Raynolds 2011)
Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group
Can mask potentially high inter- and intraspecific variability, we found better separation of bryophyte functional group means compared to previous grouping systems regarding water holding capacity

Summary

Introduction

In the Arctic, bryophytes represent 30% of all plant species (Walker and Raynolds 2011). We propose a priori defined, field-identifiable ‘bryophyte functional groups’ (BFGs) as a cost- and time-efficient, and meaningful way to increase bryophyte data resolution, allow measurement of change in bryophyte communities in response to environmental change, obtain comparable bryophyte data across tundra habitats and sites, and enhance understanding of bryophyte ecosystem effects and responses To this end, we 1) provide an overview of the role of bryophytes in tundra ecosystems and their susceptibility to environmental change; 2) review previous efforts to group bryophytes and 3) build on these efforts to propose twelve field identifiable BFGs. 4) We evaluate the relevance of these BFGs in relation to water holding capacity (WHC), a functionally important and commonly measured bryophyte trait, in a case-study where we re-analyze existing data. Such information is obtained by systematically screening species for important effect traits

Responses in bryophyte cover to environmental change in tundra ecosystems

Grouping of bryophytes

Findings

Literature