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

杂草是农业上危害最大的一类害虫。杂草补充是杂草种子成功萌发和出苗。我的研究计划的目的是确定为什么杂草招聘时，他们这样做，并探讨招聘物候对杂草的建立，竞争力和持久性的影响，旨在减少杂草对农业的影响。招募时间是杂草成功的主要决定因素。补充物候的种内异质性也很重要，因为它可以成为适应环境变化（包括气候变化）的生态策略。尽管它在这些方面的根本重要性，我们的理解杂草招聘时机的机制仍然知之甚少。通过我的发现计划研究，我们已经，到目前为止，在两个关键领域取得了进展，我的长期研究目标是能够预测气候变化对农业生态系统中杂草的入侵性，适应性和范围的影响。1)种子休眠和持久性：我们已经表明，缺乏种子休眠和种子持久性可以实质性地影响招聘物候。2)开花物候：我们已经表明，除了种子深度（和微立地条件），开花物候可以显著影响杂草补充物候。我们使用兼性冬季一年生植物（FWA）作为模式物种，并与加拿大fleabane，我们是第一个确认开花和种子棚物候，播种深度和天气模式（驱动开花物候）都是驱动杂草的招聘物候的重要因素，气候变化可能会显着影响开花物候和随后的杂草幼苗招聘物候。对杂草的了解仍然有限：a）开花物候的变化如何以及在多大程度上影响随后的生殖物候，以及开花物候在决定补充时间方面所起的作用，B）种子环境受开花物候变化和气候变化影响的程度，以及c）对杂草适合度的影响。在气候变化的背景下尤其如此，因为影响杂草生长的关键因素（即温度和降水模式）正在发生变化。我的发现研究计划的目标是描述杂草物种的招聘物候，并确定在气候变化的背景下更大的杂草成功的影响。在接下来的5年里，我将通过以下方式实现这一目标：1）在前所未有的广泛的农业生态和气候范围内建立田间实验，以收集关于杂草开花和种子脱落物候学和补充物候学以及杂草表现的独特数据; 2）使用这些数据来驱动确定性模型，以预测气候变化对杂草竞争力和入侵力的影响。

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.