Impact of Land Use Conversion on Carbon Stocks and Selected Peat Physico-chemical Properties in the Leyte Sab-a Basin Peatland, Philippines

Syrus Cesar P Decena,Edwin S Relevo,Sarah Villacorta-Parilla,Arwin O Arribado,Michael S Arguelles,Shella S Salamia,Dionesio R Macasait

doi:10.1007/s13157-021-01520-8

Abstract

Peatlands are unique wetland ecosystems that provide various ecosystem services such as carbon storage and biogeochemical cycling, however being threatened by anthropogenic activities. The present study was conducted to explore the impact of land use conversion on carbon stocks and peat properties in a tropical peatland in the Leyte Sab-a Basin Peatland (LSBP) in Northeastern Leyte, Philippines. The carbon stocks (aboveground and belowground) and physico-chemical properties of peat soil were compared among peat swamp forest, grassland and peatland with cultivation. Land use conversion resulted in the significant reduction of the total aboveground carbon stock. The peat swamp forest had the highest carbon stocks (38.56 ± 4.58 Mg ha−1), and when converted to grassland and peatland with cultivation, it has resulted to carbon loss of as much as 86.59 and 90.45%, respectively. The belowground root carbon stock was highest in the peat swamp forest (5.05 ± 0.64 Mg ha−1), also while highest peat carbon stock (1 m depth) was observed in the cultivation areas (45.28 ± 2.25 – 61.27 ± 3.07 Mg ha−1). However, peat swamp forests with very deep peat deposits potentially store a significant amount of carbon than in peatland with cultivation that was characterized by shallower compressed peats. In addition, land use conversion altered the physico-chemical properties of peat such as water content, organic matter, and porosity, and bulk density which all indicated peatland degradation. Finally, the overall result of this study highlights the importance to develop and implement management and conservation plans for LSBP.

Highlights

Tropical peatlands are great stores of terrestrial carbon (Lampela et al 2014)
The greatest number of tree species was recorded in the wetland forest (31) which was dominated by I. cymosa representing 65.85% of the total inventoried trees
The understorey layer of the wetland forest was usually dominated by M. sumatrana and S. plaustris, grassland was dominated S. scrobiculata and F. globulosa, while the cropland was represented crop species (O. sativa) and many other grasses

Summary

Introduction

Tropical peatlands are great stores of terrestrial carbon (Lampela et al 2014). They can be ombrotrophic or minerotrophic wetland ecosystems that sequester carbon (C) into vegetation and, especially, into thick peat (often > 10 m) below the forest floor (Könönen et al 2015; Page et al 2010). Due to its waterlogged and acidic condition, peatlands constitute the top long-term carbon stock in the terrestrial biosphere. This slows down the decomposition rate over preservation rate resulting in peat accumulation (Anshari et al 2010; Alibo and Lasco, 2012). This long-term ability of peatlands to absorb atmospheric carbon dioxide (CO2) from the atmosphere means that they play a major role in the regulation of global climate and greenhouse gas emissions (Alibo and Lasco, 2012; Leifeld and Menichetti 2018)

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