Exploring Arbuscular Mycorrhizal Biodiversity In Grassland Ecosystems In Uruguay

Adriana Montañez
Adriana Montañez
project abstract

Uruguay is part of the temperate subhumid grasslands in the eastern part of South America. Our territory is described as Campos within Biome Pampa according to physiognomic, geomorphologic, and edaphic features. This region shows year-round photosynthetic activity and represents one of the world's most diverse, largest, and less transformed grassland areas. Despite their apparent physiognomic homogeneity, these grasslands hold high species diversity, having grasses as the dominant life form except for a few scattered shrubs and trees. Actually, Uruguay lost 10% of its pastures.  A regional mapping work of the Pampa biome (Brazil, Argentina, and Uruguay) shows the reduction of the grassland ecosystem over two decades. Our country's main driver of pasture losses was agriculture, followed by forestry and invasive plants.

It is widely recognized the key role of arbuscular mycorrhizal fungi (AMF) in terrestrial ecosystems, as they regulate nutrient and carbon cycles influencing soil structure, plant community, and ecosystem multifunctionality. The role of mycorrhizal symbiosis has been usually related to its impact on the plant mineral nutrition However, it has been demonstrated that this symbiotic process has a key role in ecosystem stability and restauration. AMF is a mutualistic microorganism that links biotic and abiotic components of ecosystems, mediating plant competition and nutrient distribution.  Our question is, within Campos, which factors are driving and modulating AMF biodiversity? Four sites representing conserved grasslands will be sampled; we will combine different approaches to understanding AMF diversity by looking at the links between AMF and plant community structure, geochemistry, and soil microbial community interactions.

Three hypotheses are proposed: (1) AMF diversity is affected by soil type, and physicochemical environmental conditions; (2) AMF diversity responds to changes in above-ground plant community diversity; and (3) AMF diversity is affected by the interactions with soil microbial communities (fungi and bacteria) that coexist in the same site.

During this project, motivation to local communities will be through seminars and talks. Local communities, especially students from rural schools, could keep the plant communities under observation within passive conservation and restoration mini-projects aimed to involve them in a change of mind about soil health and below- and above-ground biodiversity.