MCA: Ontogenetic constraints to climate change resilience – Investigating consequences of heteroblasty under increasing aridity in New Zealand forests

MCA：气候变化恢复力的个体发育限制 — 调查新西兰森林日益干旱的情况下异质发育的后果

基本信息

批准号：
2218916
负责人：
Kasey Barton
金额：
$ 28.71万
依托单位：
University of Hawaii
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-01 至 2025-06-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2218916&HistoricalAwards=false
关键词：
MCA Ontogenetic constraints climate change

项目摘要

Forest trees are experiencing increased physiological stress due to rising temperatures, less predictable rainfall, and more extreme events such as extreme heatwaves, storms, and floods. Because plants change considerably in form and function as they grow from seedlings to juveniles to adults, the effects of climate change on plant survival and growth are expected to change with plant age. This could have large consequences for the persistence of species on the landscape. For example, an unusually hot or arid climate period after a disturbance that kills adult trees (like a hurricane or a forest fire), could cause high mortality of regenerating tree seedlings thereby limiting forest recovery. Additionally, unusual climate stressors such as prolonged drought, could lead to dieback of adult trees with consequences for watershed functioning, carbon storage and wildlife habitat. At the individual plant species scale, we do not understand how plants will tolerate climate change as they grow from juveniles to adults, particularly for long-lived plants that experience changing climates within their lifetimes. This project investigates climate change effects on several forest tree species by comparing the performance of distinct juvenile forms versus adult stage trees of several species in New Zealand forests in response to simulated droughts of two different kinds. These forests have been reduced in area by land use change and introduced animals, and their unique biodiversity is now being threatened by climate change. Island plants may be particularly vulnerable to climate change due to their limited distributions and potentially limited overall flexibility in growth traits compared to mainland forest tree species. This work will evaluate existing variability within each species across a natural climate gradient and evaluate how different populations respond to drought in a controlled greenhouse setting. The study will improve our understanding of drought tolerance in different life stages of these forest trees, help to identify the climate conditions that might be refugia where these species can continue to exist as both seedlings and adults as climate warms and dries, and also areas on the landscape where populations are likely to be highly susceptible to mortality because of juvenile sensitivity to climate change or adult tree death. This information will contribute to the conservation of native island species while engaging native Pacific Island students, and Indigenous forest managers in the research process.Plants change considerably in form and function as they grow, with the result that seedlings and juvenile trees usually differ from adult trees in leaf shape, rates of photosynthesis and water use, and in the production of spines and toxins as defense against herbivores. Such ontogenetic changes are thought to help plants survive and grow through environments that also shift as plants mature. For example, seedlings grow near the ground where it is colder, drier, shadier, and less windy than the environment adult plants experience, and they may experience different types and intensities of herbivory. For many plant species, the shifts in environmental conditions as plants pass through developmental phases are predictable, leading to the evolution of fixed developmental changes in plant form and function, a life history known as heteroblasty. Climate change is introducing new variability within short time scales, including more consecutive days without rain, more extreme rainfall events, and directional changes in mean annual rainfall. How these climatic changes will affect plants throughout their lifetimes, especially those with fixed ontogenetic shifts in form and function, is unclear. This project investigates how species with fixed (homoblastic) versus flexible (heteroblastic) ontogenetic shifts in form and function perform under climate change using a combination of approaches, including field studies to measure morphological and physiological traits in seedlings and adults across different climates, and greenhouse experiments to test the degree to which plant traits are plastic under simulated climate change conditions. Many species with fixed developmental patterns occur on islands where species are particularly vulnerable to environmental change because they have limited ranges that have been reduced by historic land use change. Hence, this project will be carried out in New Zealand where heteroblasty is common. This work will improve our understanding of climate change effects on plants as they grow up, and contribute to the conservation of native island species under the threat of global change. It will engage native Pacific Island students in research, and will work with Indigenous forest knowledge holders to exchange information on important island tree species and their potential responses to climate change.This project is jointly funded by the Population and Community Ecology program and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

由于温度升高，可预测的降雨降低以及极端的热浪，风暴和洪水，林木正在遭受增加的生理压力。由于植物在从幼苗到少年再到成年人的形式和功能发生了很大变化，因此预计气候变化对植物生存和生长的影响随着植物的年龄而变化。这可能会对物种在景观上的持久性产生重大影响。例如，杀死成年树木（例如飓风或森林大火）后，异常炎热或干旱的气候时期可能会导致更高的再生树幼苗死亡率，从而限制森林的恢复。此外，不寻常的气候压力源（例如长期干旱）可能导致成年树木死亡，对流域功能，碳储存和野生动植物栖息地产生后果。在单个植物物种规模上，我们不了解植物从少年到成年人的生长，尤其是对于长寿植物而在其一生中经历改变气候的长寿植物时，它们将如何忍受气候变化。该项目通过比较新西兰森林中不同少年形式的表现与新西兰森林中几种种类的成人舞台树的表现，以调查气候变化对几种森林树种的影响。这些森林通过土地利用变化和引入动物减少了地区，现在它们的独特生物多样性正受到气候变化的威胁。与大陆森林树种相比，岛屿植物可能特别容易受到气候变化的影响。这项工作将评估每个物种在自然气候梯度中的现有变异性，并评估不同种群在受控温室环境中对干旱的反应。这项研究将提高我们对这些林木不同生活阶段干旱耐受性的理解，有助于确定可能是避难的气候条件，这些物种可能会继续存在，因为这些物种作为幼苗和成年人作为气候温暖和干燥的地区，以及在人口易于死亡的景观中，由于对气候敏感的气候敏感，因此由于气候敏感而易于死亡或成年成年的成年树木死亡。这些信息将在吸引原住民太平洋岛屿学生的同时以及在研究过程中吸引土著森林经理的同时对本地岛屿物种的保存作出贡献。植物随着生长的形式和功能，植物的变化很大，结果是幼苗和少年树通常与叶片形状的成年树不同，光合作用的速度，光合作用的速率和水的使用，以及在抗毒素和毒素的生产中，抗抗病毒。这种种植发生的变化被认为可以帮助植物生存并通过随着植物成熟的环境而生长。例如，幼苗在较冷，更干燥，更阴凉和大风的地面附近生长，而不是成年植物所经历的，它们可能会经历不同类型和强度的食草动物。对于许多植物物种，随着植物穿过发育阶段的环境条件的变化是可以预测的，从而导致植物形式和功能的固定发育变化的演变，这是一种称为杂色的生活史。气候变化在短时间内引入了新的变异性，包括连续的几天没有降雨，更极端的降雨事件以及平均年降雨量的方向变化。这些气候变化将如何影响植物一生，尤其是那些形式和功能上固定的个体发生变化的植物。该项目调查了如何使用方法组合在气候变化下具有固定（同性细胞）与柔性（异构）的形式和功能的种类遗传学转变，包括测量不同气候的元素和成人的形态学和生理性状的现场研究，以及测试植物特质的塑料特质的塑料层次变化。许多具有固定发育模式的物种都发生在物种特别容易受到环境变化的岛屿上，因为它们的范围有限，而历史土地使用变化已减少。因此，该项目将在新西兰进行，那里是杂物很常见的。这项工作将提高我们对植物长大时对气候变化的影响的理解，并在全球变化的威胁下为本地岛屿物种的保护做出贡献。它将吸引太平洋岛屿的学生参与研究，并将与土著森林知识持有者合作，交换有关重要的岛屿树种及其对气候变化的潜在反应的信息。该项目由人口和社区生态学计划和既定的计划共同资助，刺激竞争性研究（EPSCOR）的既定奖项。这一奖项反映了NSF的法定宣传和范围的范围。