Links between leaf morphology and ecological strategy across secondary succession in a temperate deciduous forest (North Carolina, USA): Implications for the fossil record

The fossil record offers important opportunities to reconstruct plant community responses to past disturbance events. Yet, reconstructions are hindered by limited empirical evidence of successional variation in functional traits measurable on fossil leaves, including leaf morphology and δ13C. In addition, the role the leaf economic spectrum (LES) plays across succession within temperate deciduous forests is unresolved. Lastly, it is unclear to what degree disturbance confounds the leaf morphology-climate relationships utilized in paleoclimate proxies. We utilize a chronosequence spanning forest stands varied by time since logging (4, 21, 44, 94 years old), and one old-growth stand, in North Carolina. Leaf traits of woody non-monocot angiosperms (WNMA) leaves, including all trees and prominent understory plants, were measured to document patterns relating to the LES (e.g., leaf mass per area [LMA]), patterns of leaf morphology and δ13C, and the confounding influence on climatic estimates using the digital leaf physiognomy proxy.

化石记录为重建植物群落对过去扰动事件的响应提供了重要契机。然而，当前的重建工作因可通过化石叶片测定的功能性状演替变化的实证证据不足而受阻，这些性状包括叶片形态学特征与碳同位素比值δ¹³C。此外，叶片经济谱（Leaf Economic Spectrum, LES）在温带落叶林的演替过程中所发挥的作用尚未明确。最后，目前尚不清楚扰动在多大程度上会混淆古气候代用指标所依托的叶片形态与气候之间的关联关系。本研究在美国北卡罗来纳州选取了一套由采伐后不同年限（4、21、44、94年）的林分以及一处原始林林分构成的时间序列样地。研究测定了木本非单子叶被子植物（Woody Non-Monocot Angiosperms, WNMA）的叶片性状，涵盖所有乔木与优势林下植物，以记录与叶片经济谱（LES）相关的规律（例如比叶重（Leaf Mass per Area, LMA)）、叶片形态学特征与δ¹³C的变化模式，以及利用叶片形态数字化代用指标进行气候估算时所受到的混淆性影响。