Forest Fragmentation Slows the Decomposition of Coarse Woody Debris in a Subtropical Forest

Chunsheng Wu,Yuanqiu Liu,Chunjie Shu,Yi Zhang,Yanyan Li,Zhijian Zhang

doi:10.1093/forsci/fxab035

Chunsheng Wu, Yuanqiu Liu + Show 4 more

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https://doi.org/10.1093/forsci/fxab035

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Abstract

Abstract Forest fragmentation is increasing rapidly around the world, and edge effects caused by fragmented forests can influence ecosystem functions and ecological processes, including coarse woody debris (CWD) decomposition. Understanding the influencing mechanisms of edge effect on CWD decomposition is needed to assess the effects of forest fragmentation on carbon cycling and storage. We measured rates of mass loss of CWD of Cinnamomum camphora (L.) Presl. and Pinus taiwanensis Hayata over two years at two distances (0−5 m versus 60 m) from a forest edge at two altitudes (215 and 1,400 m a.s.l.), in a subtropical forest. In addition, we determined the microbial community of each CWD segment and the soil beneath via phospholipid fatty acids (PLFAs). Mass loss of CWD 60 m from the forest edge was 15% greater than that at the edge (0–5 m). Mass loss was positively correlated with the abundance of microbial and fauna community and moisture content of the decaying CWD. Distance from edge explained 17.4% of the total variation of the microbial abundance in CWD. The results indicate that the reduced abundance of microbial and fauna communities and moisture content at forest edges influenced rates of decomposition of CWD. Long-term experiments with more tree species and more forest types are needed to better assess edge effects generally.

Highlights

Forests around the world store a large amount of carbon (C) in soils, dead and living aboveground biomass, which is regarded as a significant C sink (Pan et al, 2011)
coarse woody debris (CWD) of both tree species in the forest interior had greater total Phospholipid fatty acid (PLFA), total bacteria, total fungi, G+ bacteria, G- bacteria, fungi, and arbuscular mycorrhizal fungi (AMF) compared to CWD at the forest edge
This study investigated CWD decomposition during a two-year experimental period, a relatively short time span considering the turnover time of wood

Summary

Introduction

Forests around the world store a large amount of carbon (C) in soils, dead and living aboveground biomass (including coarse woody debris: CWD), which is regarded as a significant C sink (Pan et al, 2011). Forest edges have distinct microclimates from forest interiors, including lower soil moisture, lower humidity, increased light availability, and increased wind and rain impacts (Laurance and Yensen, 1991; Didham & Ewers, 2012; Albiero-Júnior et al, 2020). These altered microclimatic conditions at forest edges can alter the decay rates of CWD. The slower mass loss was attributed to the lower humidity and moisture content of the decaying wood at the forest edge (Crockatt & Bebber, 2015). In a temperate forest in USA, Forrester et al (2012) reported higher respiration rates from CWD in canopy gaps than under intact canopy

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