Influence of Rainfall and Geography on Leaf Size and Shape: Implications for Paleoclimatic Interpretation

降雨和地理对叶大小和形状的影响：古气候解释的意义植物的叶受其环境的强烈影响。因此，化石叶子的大小和形状（外貌）几十年来一直被用来重建古代陆地景观的气候和生态条件，这也就不足为奇了。PI及其同事开发了一种称为数字叶地貌的新方法，与现有方法相比，该方法有望显着改善古环境重建。然而，数字叶地貌目前有两个基本的缺点：目前的校准是基于有限的地理范围和降雨量范围有限的网站。这限制了该方法的普遍适用性。该提案旨在测试气候（温度和降雨量）如何使用数字叶地貌方法在不同的地理环境中影响叶地貌。结果将被用来构建多变量模型，估计温度和降雨量的化石植物群，比所有现有的古植物学方法更准确。这些模型将应用于怀俄明州大角盆地的一系列化石植物群，以量化整个古新世的气候。始新世热峰期（PETM）是地球系统历史上的一个关键时期，这一建议将：（1）测试降雨对与气候有机械联系的地貌变量的影响;这些数据将有助于建立新的气候代用指标，并为理解叶地貌的功能生态学提供更丰富的框架。(2)测试叶中的电位差？]不同地理环境中的气候关系;该测试将加强气候代理，并有助于了解植物生长与环境对叶外貌的相对影响。(3)重建整个PETM的气候; PETM期间降雨的解释是有争议的，但它对于了解化石土壤的碳同位素记录和PETM的近端原因至关重要。根据这一建议，将建立一个叶图像和相关的外貌和环境数据的网络数据库;这将作为公众的教育来源，并作为研究人员以本项目范围以外的方式整合叶图像和外貌数据的数据来源。该计划将资助8？14名本科研究人员在卫斯理，主要是本科院校，从这个建议的结果将被纳入卫斯理课程。

INFLUENCE OF RAINFALL AND GEOGRAPHY ON LEAF SIZE AND SHAPE:IMPLICATIONS FOR PALEOCLIMATIC INTERPRETATIONThe leaves of plants are strongly affected by their environment. It is no surprise, then, that the size and shape (physiognomy) of fossil leaves have been used for many decades to reconstruct climatic and ecological conditions of ancient terrestrial landscapes. A new method, called digital leaf physiognomy, has been developed by the PI and colleagues that shows promise for significantly improving paleoenviromental reconstructions compared to existing approaches. However, digital leaf physiognomy presently has twofundamental shortcomings: the current calibration is based on sites with a limited geographic extent and a limited range in rainfall. This restricts the general applicability of the method. This proposal aims to test how climate (both temperature and rainfall) impacts leaf physiognomy in a diverse number of geographic settings using the digital leaf physiognomy approach. Results will be used to construct multivariate models for estimating temperature and rainfall from fossil floras that are more accurate than all existing paleobotanical methods. The models will be applied to a sequence of fossilfloras in the Bighorn Basin, Wyoming, to quantify climate across the Paleocene?]Eocene Thermal Maximum (PETM), a critical interval in Earth system history.This proposal will: (1) Test the influence of rainfall on physiognomic variables that have been mechanistically linked to climate; these data will facilitate the construction of new climate proxies and provide a richer framework for understanding the functional ecology of leaf physiognomy. (2) Test potential differences in leaf?]climate relationships in different geographic settings; this test will strengthen the climate proxies andcontribute towards understanding the relative influences of phylogeny vs. environment on leaf physiognomy. (3) Reconstruct climate across the PETM; the interpretation of rainfall during the PETM is contentious, yet it is essential for understanding carbon isotope records from fossil soils and the proximal causes of the PETM. Under this proposal, a web data bank for leaf images and associated physiognomic and environmental data will be created; this will serve as an educational source for the general public and as a data source for researchers incorporating leaf images and physiognomic data in ways outside the scope of this project. This proposal will fund 8?]14 undergraduate researchers at Wesleyan, a primarily undergraduate institution, and results from this proposal will be incorporated into Wesleyan courses.