Transients, temperature and invasive species

仅以生态系统的长期或平衡状态为基础的管理可能会忽视由临时或暂态行为引起的重要问题。我们可能会错误地认为保护行动是不成功的，因为生态系统需要数年才能做出反应，或者我们可能会认为入侵物种不会产生影响，因为长期的气候条件是不利的。例如，即使这种入侵性昆虫不会在北方城市永久存在，翠绿灰螟虫也会造成大量的城市树木清除成本（在加拿大估计为10亿美元），因为树木在入侵后5年内就会死亡。我的总体研究目标是了解和预测生态系统中瞬态行为的管理含义。瞬变的一个原因是温度波动。气候变化正在使气温变得更加多变和自相关，因此，例如，冬天比平均温度高的几年将同时发生。对这些波动的反应可能会使系统偏离平衡状态。然而，了解温度波动将如何影响整个生态系统，首先需要预测对单个物种的影响。单一物种的短暂行为对管理也很重要。在加拿大，入侵物种每年给渔业、农业和林业造成的损失约为200亿美元。自20世纪50年代以来，由于全球贸易，入侵物种的数量一直在增加，但气候变化正在加速昆虫等高度依赖温度的入侵物种的影响。当然，并不是所有的非本地物种都能在新的环境中生存，长期气候耐受性模型经常被用来预测风险。然而，这种方法并没有解决入侵物种在短期内可能增加的可能性。在接下来的5年里，我的团队将调查温度波动对入侵种群短暂行为的影响。植物、昆虫和鱼类等物种受到温度的强烈影响，温度可以改变成熟的年龄、后代的数量和生存的可能性。我们将把这些物种生活的环境温度（例如，蛀木昆虫的树皮下小气候）纳入种群模型，以预测其短期生长和持久性。我们将在受控条件下对模型物种进行预测，并将其应用于新兴的入侵物种，如亚洲长角甲虫和黑鲤鱼。该研究将进一步加深我们对瞬变的认识，为预测温度波动对生态系统的影响以及预测入侵物种的风险提供方法。我的研究小组的学生将把他们获得的定量技能转移到负责管理入侵物种的机构，如渔业和海洋部和加拿大林业局，从而确保我们的研究结果对有利于加拿大人的科学政策产生影响。

Management based only on the long term, or equilibrium, state of ecological systems can overlook important issues arising from temporary, or transient, behaviour. We may mistakenly conclude a conservation action is unsuccessful because the ecosystem takes years to respond, or we may believe that an invasive species will have no impact because the long term climate conditions are unfavourable. For example, emerald ash borer can cause large urban tree removal costs (estimated at $1 billion in Canada) even if this invasive insect does not permanently persist in northern cities, since trees die within 5 years of infestation. My overall research goal is to understand and predict the management implications of transient behaviour in ecological systems. One cause of transients is temperature fluctuation. Climate change is making temperatures more variable and autocorrelated, so that, for example, several years with warmer than average winters will occur together. Responses to these fluctuations could drive systems away from equilibrium states. Understanding how temperature fluctuations will affect whole ecosystems, however, first requires predicting impacts on individual species. The transient behaviour of single species is also important for management. In Canada, invasive species costs to fisheries, agriculture and forestry are ~$20 billion per year. The number of invasive species has been increasing since the 1950s as a result of global trade, but climate change is accelerating the impacts of highly temperature-dependent invasives such as insects. Of course, not all non-native species persist in new environments, and models of long term climate tolerances are often used to predict risks. This approach, however, does not address the probability that invasive species could increase in the short term. For the next 5 years, my team will investigate the effect of temperature fluctuations on the transient behaviour of invasive populations. Species like plants, insects and fish are strongly impacted by temperature, which can change age at maturity, the number of offspring, and probability of survival. We will incorporate temperatures of the environments where these species live (e.g., the underbark microclimate for woodboring insects) into population models to predict short term growth and persistence. We will test our predictions on model species in controlled conditions, and apply them to emerging invasives such as Asian longhorned beetles and black carp. This research will advance our understanding of transients, provide methods for predicting the impact of temperature fluctuations on ecological systems, and forecast risks from invasive species. Students on my research team will transfer the quantitative skills they acquire to agencies tasked with managing invasive species, such as the Department of Fisheries and Oceans and the Canadian Forestry Service, thus ensuring that our findings have an impact on science policy that benefits Canadians.