Impacts of environmental change in eco-evolutionary models

本研究旨在建立和分析数学模型，以了解适应过程和种群异质性如何结合影响共同进化、物种相互作用和种群规模对环境变化的响应。因此，它扩展了我目前在NSERC发现资助下开展的工作“消费者资源模型在生态学和进化中的应用”（RGPIN 227077-10）。许多种群和群落生态学的理论基础是，假设物种由相同的个体（或生物量单位）组成，其特征不会随着时间的推移而改变。虽然现在有许多文章探讨了这些概括的特殊例外，但大多数都集中在最简单的多物种例子（2-3个物种）上，并且只放松了这两个限制性假设中的一个。研究已经表明，种群异质性和个体适应性都有可能极大地改变有关物种丰度和特征如何随着其他物种丰度的变化或影响物种特性的环境变化而变化的预测。拟议的研究将分析涉及2到6个物种的简单食物网的数学模型。它将侧重于一个或多个物种的生态特征的环境引起的变化如何影响食物网中所有物种的未来丰度。这些特征包括食物摄取率、最大出生率和死亡率等。这些模型将不同于大多数先前工作中使用的模型，因为它们同时包含影响同一生态参数的行为和进化特征；例如，捕食者花在觅食上的时间以及最大捕获率。这项研究将探索在何种条件下，环境变化会增加一个物种的直接种群增长率，同时减少其最终种群规模。最近的研究（Cortez和Abrams， 2016）表明，这些特征可能出现在各种各样的简单食物网中。这里提出的研究将检验是否包括更多的相互作用的物种和物种内适应性变化的特征使这种意想不到的反应或多或少可能发生。它还应该有助于理解食物网内部的进化变化如何可能改变环境变化后发生的初始人口变化。这将有助于设计开发物种的收获策略和濒危物种的恢复计划。

This proposal seeks to develop and analyze mathematical models to understand how adaptive processes and population heterogeneity combine to affect coevolution, species interactions, and the response of population sizes to environmental change. It thereby extends the work I have carried out under my current NSERC Discovery Grant ‘Applications of consumer-resource models in ecology and evolution' (RGPIN 227077-10).***Much of population and community ecology has been based on theory that assumes that species consist of identical individuals (or units of biomass) with characteristics that do not change over time. While there are now many articles that explore particular exceptions to these generalizations, most have concentrated on the simplest multi-species examples (2-3 species) and have only relaxed one of these two restrictive assumptions. Research has already shown that population heterogeneity and individual adaptation each have the potential to dramatically change predictions about how species' abundances and traits change in response to a change in the abundance of other species or a change in the environment that affects the properties of the species. ***The proposed research will analyze mathematical models of simple food webs involving between 2 and 6 species. It will focus on how an environmentally-caused change in the ecological characteristics of one or more species affects the future abundances of all of the species in the food web. The characteristics include food uptake rates, maximal birth rates and death rates, as well as others. The models will differ from those used in most previous work by the inclusion of both behavioural and evolutionary traits influencing the same ecological parameter; for example a predator's time spent foraging as well as its maximal capture rate of prey. The research will explore the conditions under which environmental change increases a species' immediate rate of population growth while decreasing its ultimate population size. Recent work (Cortez and Abrams, 2016) has shown that such traits are likely to occur in a wide variety of simple food webs. The research proposed here will examine whether the inclusion of more interacting species and adaptively changing characteristics within species makes such unexpected responses more or less likely to occur. It should also help to understand how evolutionary change within food webs is likely to change the initial population shifts that occur following environmental change. This will help to design both harvesting strategies for exploited species and recovery plans for endangered species.