Yeast Biodiversity in Vineyard Environments Is Increased by Human Intervention

Area of Science:

• Microbiology
• Viticulture
• Ecology

Background:

• Grapevine ecosystems harbor diverse yeast communities crucial for winemaking.
• Understanding yeast biota diversity is essential for sustainable viticulture.
• The impact of human intervention on vineyard yeast diversity remains underexplored, especially in unique island environments.

Purpose of the Study:

• To investigate the impact of regular viticultural interventions on grape yeast diversity.
• To compare yeast communities in cultivated versus abandoned vineyards across the Azores Archipelago.
• To identify predominant and novel yeast species in Azorean grape samples.

Main Methods:

• Collection of 105 grape samples from 33 locations over two years.
• Isolation and identification of 3150 yeast strains.
• Analysis of yeast biodiversity using the Shannon index.

Main Results:

• 23 yeast species were identified, with Hanseniaspora uvarum, Pichia terricola, Starmerella bacillaris, and Issatchenkia hanoiensis being predominant.
• Higher yeast biodiversity was observed in actively cultivated vineyards (Shannon index: 1.89 and 1.53) compared to abandoned ones (Shannon index: 0.76 and 0.31).
• Three species (Barnettozyma californica, Candida azymoides, Pichia cecembensis) were reported in grape/wine environments for the first time. Biodiversity was lower in a high-rainfall year.

Conclusions:

• Regular human intervention in vineyards promotes higher grape yeast biodiversity, contrary to common assumptions.
• Environmental conditions, such as rainfall, significantly influence yeast community structure.
• This study provides the first report on grape yeast communities from unmanaged vineyards in the Azores.