Mycorrhizal fungi mediation of terrestrial ecosystem responses to global change: mini-review

Host plant physiology and mycorrhizal functioning shift across a glacial through future CO2 gradient

“…By examining host plant physiology and mycorrhizal functioning across glacial through future [CO 2 ], we show that plant responses to mycorrhizal fungi were weaker under the low [CO 2 ] of the past, although in T. ceratophorum, fungal symbionts still promoted plant growth under CO 2 -limiting conditions. Our results also support the hypothesis that mycorrhizal associations will become more beneficial with rising [CO 2 ] (Mohan et al, 2014); however, nonlinear responses may limit mycorrhizal benefits to some plants at the elevated [CO 2 ] of the future (Alberton et al, 2007). Furthermore, physiological mechanisms driving shifts in mycorrhizal associations were linked to host-specific differences in plant growth rate (Koziol and Bever, 2015) and vegetative plasticity as well as potential constraints on plant physiology across a long-term [CO 2 ] gradient.…”

“…Developments in mycorrhizal theory (Johnson, 2010;Johnson et al, 2015) have provided a framework for predicting how these symbioses will function as plant carbohydrate and nutrient limitations shift with rising [CO 2 ]. Yet, our understanding of mycorrhizal-CO 2 responses is primarily limited to studies comparing modern and future [CO 2 ] (Alberton et al, 2005;Mohan et al, 2014). The lack of information about mycorrhizal responses to low [CO 2 ] during the recent geologic past limits the characterization of physiological mechanisms that drive shifts in mycorrhizal functioning prior to and after anthropogenic influence.…”

“…Temporal changes in [CO 2 ] since the LGM have likely influenced the functioning of mycorrhizal associations along a continuum from mutualism to parasitism, hereafter referred to as the M-P continuum (Johnson et al, 1997), by altering plant carbohydrate production and nutrient demand. Previous mycorrhizal-CO 2 studies have focused mainly on the effects of modern versus future conditions (Alberton et al, 2005;Mohan et al, 2014), and little is known about mycorrhizal responses to low [CO 2 ] of the past (Treseder et al, 2003;Procter et al, 2014). Assessing mycorrhizal responses to a broad, temporal [CO 2 ] gradient is critical to establish a baseline for how these symbioses functioned prior to anthropogenic forcing, which will provide insight into potential constraints on mycorrhizal responses to future conditions (Ogle et al, 2015).…”

“…Furthermore, the majority of C 3 plants show some level of increased photosynthetic rates, leaf carbohydrate levels, and biomass when grown at future [CO 2 ] (Ainsworth and Rogers, 2007;Prior et al, 2011). However, plants may require more nutrients in order to maintain high rates of photosynthesis and growth at elevated [CO 2 ] (Campbell and Sage, 2006;Lewis et al, 2010 (Mohan et al, 2014). However, the functioning of mycorrhizal associations at low [CO 2 ] of the past remains unclear.…”

The last 50 years of climate‐induced melting of the Maliy Aktru glacier (Altai Mountains, Russia) revealed in a primary ecological succession

“…At the Small Aktru glacier, ectomycorrhizal fungi were found to partially replace saprotrophs at a distance from the glacier forefront higher than 350 m. Mycorrhizal fungi are responsible for most nutrient uptake by the majority of land plants and are increasingly recognized as important drivers of terrestrial ecosystem processes (Mohan et al., 2014). As diverse plants species start to establish in the in the earliest colonized sites organic matter slowly accumulates in the soil and microbial and mycorrhizal fungal populations increase and become dominant over time.…”