DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 5-6/2021 str. 79 <-- 79 --> PDF |
acidification and pollutants, ecosystem fragmentation and habitat loss, and biotic invasion. These factors impact soil-rhizosphere, plant and fungal physiology and entire ecosystem directly and indirectly. Direct effects include changes in resources available to mycorrhizas and change in distribution of mycorrhizas. Indirect effects include changes in carbon allocation below ground to roots and mycorrhizas and changes in host plant species distribution (Bellgard and Williams, 2011). Climate change ecological drivers can be divided according to the time frames related to the longevity of their influence on the planet and nature. Ecosystem fragmentation and habitat loss have immediate impacts (1–2 years); biotic invasions of exotic mycorrhizal fungi, plants and pests, diseases and other abiotic perturbations have short-term impacts (3–10 year); cumulative and additive effects of increased nitrogen (N) and sulphur (S) deposition, soil acidification and other pollutants have intermediate-term impacts (11–20 year); increase of CO2 concentration in the atmosphere and temperatures are destabilizing global rainfall patterns, soil properties and plant ecosystem resilience which have long-term impacts (21–50+ year) on the whole planet (Bellgard and Williams, 2011). Effects of increasing CO2 concentration in the atmosphere on mycorrhizae – Učinci povećanja koncentracije CO2 u atmosferi na mikorize Since the beginning of the Industrial Revolution (1750–1800), concentration of CO2 in the atmosphere has increased from 280 ppm (parts per million) to approximately 400 ppm at present. This CO2 increment is strongly correlated with increase in fossil fuels consumption and change in land use (Houghton, 1988; Bellgard and Williams, 2011). Increase of atmospheric CO2 can affect mycorrhizal fungi indirectly through its impacts on host plants. Generally, plants can respond to this increase with higher productivity and their mycorrhizal symbionts can be proportionately larger (Staddon et al., 2002). Hence, higher plant productivity increases water and nutrient demands and increased photosynthesis enables plants to transfer more carbon belowground to roots and mycorrhizas (Pritchard et al., 2008), which stimulates mycorrhizal abundance and activity and favors the development of more extensive mycorrhizal networks with higher transfer capacity (Simard and Austin, 2010). However, under low N availability, increased CO2 stimulates aboveground and belowground biomass in ECM plants but has no effect in AM plants. So, only plants in association with ECM fungi can overcome nitrogen limitation (Terrer et al., 2016). Increase of CO2 concentration in the atmosphere could cause alteration in mycorrhizal community structure as well. This change is dependent on the abilities of different fungal taxa to exploit carbon pools and nutrients or to adapt to the changing environment (Staddon et al., 2002; Simard and Austin, 2010). When elevated CO2 in the atmosphere increases belowground carbon allocation and stimulates nutrient deficiencies, exploration types of ECM fungi with hydrophobic rhizomorphs (medium- to long-distance exploration types) may be favoured because of their specific exploration strategies for accessing insoluble or stable nutrient patches (Hobbie and Agerer, 2010; Lilleskova et al., 2011). Since the effects of increased CO2 in the atmosphere on plants are species-specific, plant community structure is also changed, which will in turn cause alteration in the community of mycorrhizal fungi in environment with enriched CO2 (Staddon et al., 2002). Effects of increased air and soil temperature on mycorrhizae – Učinci povećanja temperature zraka i tla na mikorize The global surface temperature (calculated by averaging the temperature at the sea surface and air temperature over land) has increased over the last century by approx. 0.6°C (Bellgard and Williams, 2011). It was proved that temperature has direct effects on mycorrhiza. Namely, temperature affects the amount of resources available to mycorrhizas and distribution of mycorrhizas and their propagules. All organisms have temperature optimum because enzymatic activity is highly dependent on temperature. Since temperature affects plants it will also indirectly affect mycorrhizal fungi through its effects on their host plants (Staddon et al., 2002). Generally, plant growth can be increased with soil temperature, but it can be decreased if nutrients or water in soil are deficient or reduced. On the other hand, warming is likely to increase respiration and decomposition rates and has the potential to change the availability of soil nutrients. To meet increasing demands for nutrients and water under increased temperature, mycorrhizal fungi will enhance their activity as the plants increase their productivity with soil temperature rise. In soil warming conditions, mycorrhizal fungal abundance has been shown to increase and community of ectomycorrhizal fungi has been recorded to change toward dominance of fungi with long-distance exploration capabilities that enable them to compete for scarce nutrients and contribute to soil carbon storage (Pendal et al., 2004; Simard and Austin, 2010). Effects of alteration in precipitation pattern on mycorrhizae – Učinci promjene distribucije oborina na mikorize It is certain that climate change is going to alter precipitation pattern locally, i.e. its intensity, frequency, duration, and amounts, which is likely to cause episodes of drought (Bellgard and Williams, 2011). Increased frequency and |