Litterfall (consisting of fallen leaves, branches, flowers and fruits, bark, mosses, and other fractions) is an indicator of a disturbed forest ecosystem and its temporal dynamics can be used to evaluate the recovery trajectory of self-organizing ecosystems. Drought events affect litter input, which in turn affects nutrient and energy cycling in forest ecosystems. However,studies on the dynamics of production of litter fraction in response to extreme drought are limited.
In a study published in Ecological Indicators, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) investigated the effects of extreme drought events on litterfall production in a subtropical evergreen broad-leaved forest and the differences in litterfall recovery mechanisms under different seasons (year-round, concurrent drought, non-drought period, rainy season and dry season).
The researchers used monthly litter production and climate data for 10 years (2005-2014) to investigate the relationships between litter production and environmental factors, including monthly average precipitation (MAP), soil water content (SWC) and monthly average temperature (MAT). The observation period was divided into three stages: before drought (2005-2008), during drought (2009-2010) and after drought (2011-2014).
Through statistical analysis methods, they explored the effects of different factors on litterfall production and determined the dominant factors. They found that extreme drought events caused a decrease in litter production in the subtropical evergreen broad-leaved forests of Ailao Mountains, and water environmental factors contributed more significantly to litter inputs after drought events.
They further found that monthly average precipitation, soil water content and monthly average temperature jointly affected litter input under extreme drought conditions, and the dominant factor was related to litter fraction and drought periods. Extreme drought events directly reduced litterfall quantity and enhanced the proportion of leaves, which remained to be the main fraction of total litterfall. Different components had different recovery times, which are related to their growth and nutrient strategies, with the order of recovery time as: branch < leaf < flower fruit < moss < bark.
“Our findings help to understand the effects of drought on energy and material cycling in forest ecosystems and litter recovery mechanisms,” said ZHOU Wenjun of XTBG.
Contact
ZHOU Wenjun Ph.D
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: zhouwj@xtbg.ac.cn
Published: 5 August 2024
