Ectomycorrhiza succession patterns in Pinus sylvestris forests after stand-replacing fire in the Central Alps

Abstract

Fires shape fundamental properties of many forest ecosystems and climate change will increase their relevance in regions where fires occur infrequently today. In ecosystems that are not adapted to fire, post-fire tree recruitment is often sparse, a fact that might be attributed to a transient lack of mycorrhizae. Ectomycorrhizal (EcM) fungi play an important role for recruitment by enhancing nutrient and water uptake of their hosts. The questions arise whether and for how long the EcM community is transformed by fire. We investigated the resistance and resilience of EcM fungal communities on a chronosequence of 12 Pinus sylvestris stands in Valais (Switzerland) and Val d'Aosta (Italy) affected by fire between 1990 and 2006. Soil samples from burnt and non-burnt forests were analyzed with respect to EcM fungi by means of a bioassay. The number of EcM species was significantly lower in samples from recently (2-5 years) burnt sites than nonburnt forest, and increased with time since fire reaching levels of adjacent forests after 15-18 years. Community composition changed after fire but did not converge to that of non-burnt sites over the 18 year period. Only Rhizopogon roseolus and Cenococcum geophilum were abundant in both burnt sites and adjacent forest. Our data indicate fire resistance of some EcM fungal species as well as rapid resilience in terms of species number, but not in species composition. As long as the function of different EcM species for seedling establishment is unknown, the consequences of long-term shifts in EcM community composition for tree recruitment remain unclear.

Below-Ground Ectomycorrhizal Community Structure in the Postfire Successional Pinus koraiensis Forests in the Central Sikhote-Alin (the Russian Far East)

“…However, we did not reveal a clear trend of OTUs numbers increasing with time period since fire increase, as it was shown, for example, for EcM succession patterns in Pinus sylvestris forests after fire (Kipfer et al 2011).…”

“…and Russula spp. Some of these taxa are ac tual ly considered as typical earlystage fungi occurring pri ma rily in young coniferous forests (Visser 1995, Grogan et al 2000, Aučina et al 2011, Kipfer et al 2011 These groups of fungi (earlystage and latestage) differ from each other not only in connection with different age of hosttree, but also the ability to extract nitrogen from one or another substrate. The latestage EcM fungi emerge as a major component in the older fragmented litter and hu mus, i.e.…”

Consequences for ectomycorrhizal fungi of the selective loss or gain of pine across landscapes

“…Effects on species richness and (or) diversity were variable but shifts in species composition were common (e.g., Kipfer et al 2011;Rincón and Pueyo 2010) (Table 1). Colonization of roots was predominantly by resistant propagules in stands of Pinus muricata (Baar et al 1999) and differences among species of propagules in sensitivity to high soil temperatures could contribute to shifts in fungal species composition.…”

Ectomycorrhizal fungal spore bank recovery after a severe forest fire: some like it hot

“…All other studies of post-fire ECM fungal recovery have primarily used space-for-time comparison where different aged fires were studied (Buscardo et al, 2010;Kipfer et al, 2011), laboratory heating experiments (Izzo et al, 2006;Peay et al, 2009;Kipfer et al, 2010) or low-intensity prescribed fires where host death was not involved (Stendell et al, 1999;Brown et al, 2013). Studying the effect of stand-replacing fire on fungi is particularly challenging because wildfire events are unpredictable and pre-fire data are seldom available.…”