Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611-7800 USA.
Am J Bot. 2009 Jun;96(6):1108-15. doi: 10.3732/ajb.0800361.
One method to determine past climate has been the use of leaf morphological characteristics of fossil leaves quantified using modern climate and canopy leaf characteristics. Fossil assemblages are composed of abscised leaves, and climate may be more accurately determined by using leaves from leaf litter instead of the canopy. To better understand whether taphonomic processes make a difference in this relationship, a north-central Florida woodland was sampled to determine the morphologically based climate estimates from these leaves. Leaves from woody, dicotyledonous plants were collected and identified, then compared using presence/absence data and analyzed using several linear regression equations and the CLAMP data set. Although the majority of standing vegetation was reflected in leaf litter, some inconsistencies were observed, which may reflect plant community structure or sampling technique. Mean annual temperature (MAT) and growing season precipitation (GSP) were estimated from leaf litter morphological characters and living leaves. Overall, values for MAT estimated from litter and living leaves were cooler than actual MATs, although several accurate and high estimates were obtained depending on the predictive method used. Estimated GSP values were higher than actual GSPs. Statistically, no difference was observed between MAT and GSP estimates derived from leaf litter vs. estimates derived from living leaves, with one exception.
一种确定过去气候的方法是利用现代气候和树冠叶特征对化石叶的形态特征进行量化。化石组合由脱落的叶子组成，通过使用落叶而不是树冠的叶子，可能更准确地确定气候。为了更好地了解化石保存过程是否会影响这种关系，对佛罗里达州中北部的一个林地进行了采样，以确定这些叶子所代表的形态学基础气候估计值。收集并鉴定了木本双子叶植物的叶子，然后使用存在/缺失数据进行比较，并使用几个线性回归方程和 CLAMP 数据集进行分析。尽管大部分立木植被都反映在落叶中，但观察到一些不一致之处，这可能反映了植物群落结构或采样技术。落叶形态特征和活叶估计了年平均温度 (MAT) 和生长季降水量 (GSP)。总体而言，落叶和活叶估计的 MAT 值比实际 MAT 值低，尽管根据使用的预测方法，获得了几个准确和高的估计值。估计的 GSP 值高于实际 GSP 值。统计上，来自落叶的 MAT 和 GSP 估计值与来自活叶的估计值之间没有观察到差异，除了一个例外。
