Could original pH and vegetation condition fungal role after fire?
Different fungal and bacterial response after fire is one of the first evidences that were reported in the literature. Divergent heat-resistance, different competitive capacities or even variable sensitivity grade to toxics substances have been proposed as the key factors determining these changes. In the last years, original soil pH and pH fire-induced changes have started to gain importance in the fungal and bacterial behaviour after fire, in both, wildfire and laboratory heating researches (Bárcenas-Moreno et al., 2011; Bárcenas-Moreno et al., 2016a; Bárcenas-Moreno et al., in press). Fungal proliferation is associated to low original pH (pH < 7, or acid conditions), owing to fungi appears to be more competitive than bacteria at this pH, although fungi can proliferate without problem at pH above 7. Therefore, bacteria proliferation after fire is related to pH fire-induced increment associate to ash deposition. Bárcenas-Moreno et al. (2011) found evidences of fungal facilitation to bacterial recovery when pre- and post-fire soil pH is below 7. One possible explanation suggested is related to fungal enzymatic capacities, which could allow fungi to be more competitive against fire-induced organic toxics compound, being releasedby partial combustion of organic matter. Fungal detoxification of soil in the first post-fire moment could facilitate subsequent bacterial colonization. In addition, we should take into account that vegetation plays an important role determining microbial community composition and function, since, plant species composition conditions organic matter quantity and quality (Bárcenas-Moreno et al., 2014). Thus, the establishment of fungal community associated to different plant community and soil pH, could allow us predict the potential response of microbial community after fire conditioned by pH fire-induced changes. In this preliminary study to deepen the fungal role in soil ecology after fire, we isolate soil fungi from, different forest unaltered areas with different pH and original vegetation, and fungal abundance. Diversity and enzymatic capacity to degrade Polycyclic Aromatic Hydrocarbons (PAHs) of viable and cultivable fungi were analysed. In addition, in one of the forest areas selected, we include an area that was burnt 6 years before and compare with the unburnt one. Soil samples were collected under the influence of pine, holm oak, kermes oak, cork oak, rockrose and high mountain shrubs from different geographical areas in the South of Spain. Soil samples collected under cork oak showed the highest viable and cultivable fungal abundance of all samples studied, while soil from high mountain shrubs displayed the lowest one. Nevertheless the number of different fungi isolated was more variable. The average percentage of fungi with laccase activity among all isolates was around 20%, with the highest percentage found under high mountain shrubs and the lowest one under pine on basic conditions (pH < 7) where no isolate was found with this activity. The results obtained in this preliminary study can help us to design new project in order to determine the potential role of fungi in different forest environment susceptible to suffer a wildfire in the future.
| Main Authors: | , , , , |
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| Format: | póster de congreso biblioteca |
| Published: |
Universidade de Aveiro
2016-11-23
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| Online Access: | http://hdl.handle.net/10261/158857 |
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