ABSTRACT
This study investigates the effects of forest aging on ectomycorrhizal (EcM) fungal community and foraging behavior and their interactions with plant-soil attributes. We explored EcM fungal communities and hyphal exploration types via rDNA sequencing and investigated their associations with plant-soil traits by comparing younger (~120 years) and older (~250 years) temperate forest stands in Northeast China. The results revealed increases in the EcM fungal richness and abundance with forest aging, paralleled by plant-soil feedback shifting from explorative to conservative nutrient use strategies. In the younger stands, Tomentella species were prevalent and showed positive correlations with nutrient availability in both the soil and leaves, alongside rapid increases in woody productivity. However, the older stands were marked by the dominance of the genera Inocybe, Hymenogaster, and Otidea which were significantly and positively correlated with soil nutrient contents and plant structural attributes such as the community-weighted mean height and standing biomass. Notably, the ratios of longer-to-shorter distance EcM fungal exploration types tended to decrease along with forest aging. Our findings underscore the integral role of EcM fungi in the aging processes of temperate forests, highlighting the EcM symbiont-mediated mechanisms adapting to nutrient scarcity and promoting sustainability in plant-soil consortia.
ABSTRACT
Drought and flood are two frequent natural disasters in the world. Identification of temporal-spatial variability and its scale-dependence for drought-flood correlation can help to predict, hence to alleviate the losses. The correlations of drought with flood at 1, 3, 5, 10, 50 and 100-year scales at moving window of 30years during recent 500years were analyzed by spatial statistics based on geographical information system in Inner Mongolia, China. The results demonstrated that the frequency and intensity of two disasters increased generally during last 500years. The drought-flood correlations indicated a rhythm of alternate positive and negative relation with unspecific timescale, enlarged by prolonging of time scale from 1year to 5years, for either frequency or intensity. A lag effect, flood always occurred at the 4 or 5year following drought was observed. Located in the climatic marginal zone, eastern study region was strongly affected by the East Asia monsoon, showed a weak drought-flood correlation; western study region was controlled by continental climate, showed a significant drought-flood correlation. These correlations were also affected by periodic ENSO disturbance and mountain terrains. With the climatic changes, the drought-flood correlations also change in recent decades. These long-range correlations at various temporal-spatial scales provide a theoretical basis for the scientific prediction of drought and flood outbreaks, for a long term as well as a short wavelet.
