Cons and prons of metabarcode analysis of fungi for fungal conservation: implications from a large scale monitoring of soil fungi in Swedish forests 2014-16.

Abstract

A challenge for getting adequate information of the identity and composition of soil fungal diversity, hence for fungal conservation, is the largely cryptic life of fungi. Several years’ lack of sporocarps does not necessarily imply absence of fungal species as mycelial activity may poorly correlate to the irregular and strongly weather dependent production of sporocarps. Furthermore, sporocarps are short-lived, morphological identification of many taxa require specialist competence and several species have inconspicuous, or may even lack, sporocars.

One approach to circumvent these difficulties, and to complement sporocarp monitoring, is to use metabarcode analysis of e.g. soil and wood to identify fungal communities based on the presence of fungal mycelia. The appealing power of using this methodology is that all fungal taxa present, will in principal be detected and identified at any time of the year. On the other hand, a significant limitation is that only fungi present in the minute samples can be detected. Fungal species richness and diversity is typically very high. Few species are frequent and abundant while red-listed and of conservation interest typically are rare.

Annually since 2014, forest soil fungi are identified and monitored nationally throughout Sweden by metabarcode analysis of soil samples collected in permanent forest plots by the Swedish Forest Soil Inventory (SFSI) and the Swedish National Forest Inventory (SNFI). Hereby, fungal communities from all types and ages of forest with varying histories and management are efficiently collected and identified with a high resolution and precision. Importantly, the fungal communities can be analysed with all associated environmental metadata collected by SFSI and SNFI.

This talk will present the results of fungi identified from the about 900 stands analysed during 2014-2016 with a focus on red-listed species. A comparison will be made with sporocarp records of the corresponding species reported in the Swedish Species Gateway. The results will be discussed in the perspective of red-list assessments and the value and implementation of this type of metabarcode data in fungal conservation.