Population consequences of sexually dimorphic responses in a plant species to ongoing and experimental changes in climate

预测一群生物将如何对它们所经历的气候变化做出反应，需要了解生态过程中的小范围变化如何转化为大范围的模式。大多数关于生物对环境变化的反应的研究要么记录了整个物种对过去变化的自然反应模式，要么记录了实验操纵的环境对少数个体表现的影响。前一种方法得益于其现实主义，但过于粗糙，无法阐明对气候变化的反应背后的生理反应。后一种方法详细地演示了这些机制，但它是在小空间尺度和人为简化的实验条件下进行的。这项研究试图在这两种方法之间架起一座桥梁，研究科罗拉多州落基山脉野外气候变化对香草的反应。这个物种的个体有不同的性别(即要么是男性，要么是女性)，性别对气候变化的反应是不同的。研究人员将研究这些可变的、个体水平的气候反应如何放大，以确定种群动态和物种持久性。这项工作将在落基山生物实验室(RMBL)进行，使用历史和当代人口统计数据来比较空间气候变化(1800米海拔梯度)、实验操作(变暖和除雪)和时间(40年创纪录)之间的影响。这项研究还通过本科生和研究生科学培训、公民科学倡议以及通过与RMBL合作开发基于网络的课程来提供教育和推广的机会。这项研究询问雌雄异株物种中的雄性和雌性对气候变化的性别中介生理反应是否会扭曲种群结构(性别比)，从而产生人口统计学后果。研究人员将使用种群在(1)历史气候、(2)物种海拔范围内的当代气候和(3)实验变暖和除雪的情况下的生命率、交配功能、水分利用效率和初级(种子)性别比的历史和当代数据，构建大小和性别结构的人口模型。通过模型选择和生命表响应实验分析，本研究评估了气候的空间变化(海拔1800米)、时间变化(过去和现在)和人为变化(现在和模拟未来)对种群表现的总体影响，以及气候偏斜性别比的具体贡献(和生理基础)。

Predicting how a population of organisms will respond to changes in the climate they experience requires understanding how small-scale changes in ecological processes translate to patterns at broad scales. Most studies of biological responses to environmental change have either documented the natural pattern of whole-species response to past change or, alternatively, the effects of experimentally manipulated environment on the performance of a few individuals. The former approach benefits from its realism, but is too coarse to elucidate the physiological responses underlying the response to changes in climate. The latter approach demonstrates these mechanisms in detail, but does so at small spatial scales and under artificially simplified experimental conditions. This study seeks to bridge these two approaches, studying the responses of the plant Valeriana edulis to climatic variation at field sites in the Colorado Rockies. Individuals of this species have separate sexes (i.e. are either male or female) and the sexes respond differently to changes in climate. The researchers will investigate how these variable, individual-level responses to climate scale up to determine population dynamics and species persistence. This work will be conducted at the Rocky Mountain Biological Laboratory (RMBL) using historic and contemporary demographic data to compare the effects of a changing climate over space (an 1800 m elevational gradient), between experimental manipulations (warming and snow removal), and over time (40 year record). This study also provides opportunities for education and outreach through undergraduate and graduate scientific training, citizen science initiatives, and through the development of web-based curricula in collaboration with the RMBL.This research asks whether the sex-mediated physiological response of males and females in dioecious species to changes in climate can skew population structure (sex ratios) with resultant demographic consequences. The researchers will construct size- and sex-structured demographic models using historic and contemporary data on vital rates, mating functions, water use efficiency and primary (seed) sex ratio for populations under (1) historic climate, (2) contemporary climate over the species' elevation range, and (3) experimental warming and snow removal. Using model selection and life table response experiment analyses, this study assesses the overall consequences of spatial (1800 m elevation), temporal (past vs. present) and manipulated (present vs. simulated future) variation in climate for population performance, as well as the specific contribution of (and physiological basis to) climate-skewed sex ratios.