Diversity of cover crops in two organic vineyards in the Niagara Region, Canada, as an adaptation measure to climate change

Abstract

Vineyards are agroecosystems of great importance in the Niagara Region, Ontario (Canada). Due to its microclimate, this region is projected to be impacted by climate change with temperature increases, changes in precipitation patterns in all seasons, and greater frequency of extreme weather events. The aim of this thesis was to explore the projected changes for the weather in the Niagara Region, Canada, summarize which seasonal changes are expected and assess how such changes are likely to affect the key components of the vineyard ecosystem (i.e., soil, vines, invertebrates, and pathogens). It is expected that by 2080 the region will experience an increase in temperature in all four seasons; an increase in precipitation during the fall, winter, and spring; and a decrease in precipitation during summer months. Impacts of the projected changes will likely lead to vine water stress, yield loss, increases in incidents of diseases, increases in the spread of new pests, and changes in grape quality ultimately resulting in lower wine quality and/or production. Current management practices will need to be better understood and adaptive strategies introduced to enhance grape growers’ ability to minimize these impacts. The research also aimed to test the performance of four different cover crops in monoculture or in mixture in two organic vineyards. Of the planted species, rye grass and hairy vetch showed a great establishment, while pearl millet did not establish due to weed pressure. The ecological indexes (Shannon, Simpson’s, and Evenness) values showed that there is significant difference in cover crop diversity between growing seasons and collection months (June/September) in Vineyard #2, and in richness in Vineyard #1, indicating fluctuations in community composition over time. These results suggest a dynamic ecosystem response to seasonal and annual variations. These results may be used to increase the knowledge about the expected future for the vineyards in the region in face of climate change, and into one of the alternative management techniques that can help mitigate the impacts of changes in temperature and rainfall increase of extreme events in the region.