Dados do Trabalho

Título

LONG-TERM CHANGES IN SOIL FUNCTIONALITY AND MICROBIAL DIVERSITY IN NATIVE FOREST AND PINE PLANTATION WILDFIRE CHRONOSEQUENCE.

Resumo

Wildfire effects on ecosystem functioning have increased due to climate change fears. Short-term fire effects on forest soils are well understood, but long-term effects on soil microbial biomass, activity, and diversity are unknown. These variables affect fire severity, soil quality, environmental conditions, and time in unknown ways. This research’s aim is to evaluate the 22-year influence of a single severe wildfire on soil microbial community diversity and activity in exotic forest plantation (Pinus radiata) and native forest (Nothofagus spp.) from the Chilean Andes Cordillera in the Mediterranean bioclimatic zone. For this purpose, soil from a burned native forest (BNF) and pine plantation (BPP) was sampled 4, 6, and 22 years after the fire and compared to soil from an unburned neighboring region (NF and PP). Soil enzymatic activity was measured, as well as DNA fragments from the soil metagenome. The impact of fire on soil was also assessed using selected enzyme activity as valid bioindicators of biogeochemical cycles. Although microbial biomass was not significantly changed, there was an immediate fire-induced general fall in enzyme activity and more durable changes in the structure of the bacterial and arches communities. After 6 years of wildfire, BNF showed a decrease in activity of acid phosphatase (AP), leucyl aminopeptidase (LAP), polyphenol oxidase (PPO), and peroxidase (POD) compared to NF. Celobiohydrolase (CBH), b-glucosidase (BG), and b-N-acetylglucosaminidase (NAG) activity increased after the same time period. Although BPP was compared to PP, same pattern was observed for AP, CBH, LAP, and PPO activity after 6 years. After a year, the litter layer showed DNA, a structured microbial community, and enzyme activity. The fire-survived microbial biomass that responded to the changing soil conditions likely helped the fast recovery.

Palavras-chave

Microbial Biomass, enzymatic activity, extracellular DNA, forest soil, soil microbial community.

Instituição financiadora

Funded by ANID FONDECYT regular N◦1220716 , ANID FONDECYT regular N◦1220786 and ANID Anillo N◦ACT210060.

Agradecimentos

Heartfelt thanks to the Laboraotrio de Geomicrobiología and the Laboratorio de Conservación y Dinámica de Suelos Volcánicos.