Characterizing the emergence timing of weed species and determining implications for greater weed success in the context of climate change

点击翻译按钮获取中文摘要

Weeds are the most harmful category of pests in agriculture. Weed recruitment is the successful seed germination and seedling emergence of weeds. The purpose of my research program is to determine why weeds recruit when they do and to explore the implications of recruitment phenology on weed establishment, competitiveness and persistence with an aim to reducing the impact of weeds on agriculture. Time of recruitment is a prime determinant of weed success. Intra-specific heterogeneity in recruitment phenology is also important because it can be an ecological strategy for adapting to environmental change including climate change. Despite its fundamental importance in these respects, our understanding of the mechanisms of weed recruitment timing remain poorly understood. Through my discovery program research we have, to-date, made progress in two key areas toward my long-term research goal of being able to predict the impact of climate change on the invasiveness, fitness and range of weeds in agro-ecosystems. 1) Seed dormancy and persistence: we have shown that a lack of seed dormancy and seed persistence can substantively affect recruitment phenology. 2) Flowering phenology: we have shown that in addition to seed depth (and microsite conditions), flowering phenology can significantly affect weed recruitment phenology. We use facultative winter annuals (FWA) as model species and with Canada fleabane, we were the first to confirm that flowering and seed shed phenology, seeding depth and weather patterns (driving flowering phenology) are all significant factors driving the recruitment phenology of weeds and that climate change could significantly impact flowering phenology and subsequent seedling recruitment phenology for weeds. There remains a limited understanding for weeds of a) how and to what extent changes in flowering phenology influence subsequent reproductive phenology and the role that flowering phenology plays in determining time of recruitment, b) the extent to which seed environment is impacted by changes in flowering phenology and climate change and c) the implications for weed fitness. This is especially true in the context of climate change where the key factors affecting weed recruitment (i.e. temperature and precipitation patterns), are changing. The objective of my discovery research program is to characterize the recruitment phenology of weed species and to determine the implications for greater weed success in the context of climate change. Over the next 5 years I will pursue this objective by 1) establishing field experiments across an unprecedented broad agro-ecological and climatic range to collect unique data on weed flowering and seed shed phenology and recruitment phenology and weed performance, and 2) using this data to drive deterministic models for predicting the impact of climate change on the weed competitiveness and invasiveness.