Peatland Degradation Reduces Microbial Richness and Alters Microbial Functions in an Australian Peatland

Peatland ecosystems cover only 3 % of the world’s land area, however they store one-third of the global soil carbon (C). Peatlands play a central role in global C cycling as they contain more organic C than any other terrestrial ecosystem. Microbial communities are the main drivers of C decomposition in peatlands, yet we have limited knowledge of their structure and function. We investigated the vertical stratification of prokaryote and fungal communities from Wellington Plains peatland in the Australian Alps. Within the peatland complex, bog peat was sampled from the intact peatland and dried peat from the degraded peatland along a vertical soil depth gradient (i.e., acrotelm, mesotelm and catotelm). We analysed the prokaryote and fungal community structure, predicted functional profiles of prokaryotes using PICRUSt and assigned soil fungal guilds using FUNGuild. We found that the structure and the function of prokaryotes was vertically stratified in the intact bog. Carbon, manganese, nitrogen, lead and sodium best explained the prokaryote composition. Prokaryote richness was significantly higher in the intact bog acrotelm compared to degraded bog acrotelm. Fungal composition remained similar across the soil depth gradient, however there was a considerable increase in saprotroph abundance and decrease in endophyte abundance along the vertical soil depth gradient. The abundance of saprotrophs and plant pathogens was two-fold higher in the degraded bog acrotelm. Manganese, nitrogen, electrical conductivity and water table level (cm) best explained the fungal composition. Our results demonstrate that both fungal and prokaryote communities are shaped by soil abiotic factors and peatland degradation reduces microbial richness and alters microbial functions. Thus, current and future changes to the environmental conditions in these peatlands may lead to altered microbial community structure and associated functions which may have implications for broader ecosystem function changes in peatlands.

Opportunities and challenges for land use-based peatland restoration in Kayu Labu Village, South Sumatra, Indonesia

Restoration of degraded peatland has proven to be complex and many activities that have been initiated in recent years have not had a significant impacted on restoring peatland condition. Revitalization activities that have been carried out in several locations have not been effective. Likewise, rewetting actions were often poorly understood by the community. This research aimed to analyze land use-based peatland restoration opportunities and challenges in Kayu Labu village, South Sumatra. Survey methods and interviews with the stakeholders were applied to collect primary data in the field. The results showed that although Kayu Labu has been designated as one of the focus villages for restoration by the Peatland Restoration Agency, the restoration efforts to date have not significantly impacted on people’s lives. The community has not widely known the implementation of the programs, and only those who were directly involved in the activities were aware of the peatland restoration program. Several opportunities are available to support the implementation of land use-based peatland restoration in Kayu Labu: the community has a strong willingness and commitment to restore their peatlands because they have suffered badly from peatland fires in the past. The community also acknowledges the loss of their livelihoods due to peatland degradation, especially for purun craftsmen, gelam collectors, and fishers. There are also opportunities from government and research programs to be implemented in this area to support peatland restoration. However, there are still challenges that must be faced: the increasingly massive expansion of oil palm plantations by clearing the peatlands, the lack of knowledge about peatland, and there is a general feeling from the community that without peatland their lives would be better off because they could grow diverse crops with higher yields. Therefore, capacity building, communication and knowledge enhancement, and partnerships are needed for the success of land use-based peatland restoration in Kayu Labu.

Challenges to peatland restoration in Indonesia

<p>Challenges to peatland restoration in Indonesia<br>By <br>Nyoman Suryadiputra*) </p><p><br>Tropical peat swamps in Indonesia are currently experiencing degradation at a very alarming rate. Degradation starts from the time of land clearing (generally burned / uses fire) for both private and community-owned plantations, then a very massive network of drainage canals is built (every 1 Ha of peat land cleared, about 120 m - 700 m long canals are needed). These drainage canals aim to reduce the surface water level of peat so that the land can be planted (especially for) oil palm or acacia. However, peat water release can go out of control, beyond the peatland water level threshold determined by government regulation No 71/2014 on Peatland Management, as a result peat becomes dry, flammable and emits large amount of GHGs. In the long run, if drainage and fires continue, peatlands will experience subsidence, form basins, peat even disappear, flooded during rain and eventually the land becomes unproductive (stranded) and difficult to restore. Such conditions will be more severe and difficult to overcome if in the landscape (peatland hydrology unit) there are various activities by various parties, each of whom has different interests and understandings of peatland use. Regarding the above, restoration of peatland that has been damaged has a very serious challenge. Damage that is getting heavier will have a high level of difficulty and a long recovery time. In addition, the success rate of restoration is determined by benchmarks or recovery criteria that have not been scientifically determined and adopted by the Indonesian government.</p><p><em>Keywords : peatland, degradation, landscape, restoration    </em></p><p><br>*)  Director of Wetlands International Indonesia</p>

Microbial-derived phospholipid fatty acids approve the link of stable isotope depth pattern to peatland hydrology

<p>Ongoing peatland degradation calls for an efficient method to indicate peatland hydrology and the success of restoration effort. In previous studies we found specific depth patterns of 13C and 15N depending on peatland hydrology (drained, rewetted or natural), but were unable to find an explanation of these patterns. As degradation is mostly connected to drainage we assumed an increase of microbial activity. This microbial activity should then be imprinted in stable isotope signatures (15N, 13C) due to differences in microorganism communities, their metabolic pathways and nutrient sources. We aimed to find a link between our investigated isotope depth patterns to microbial community composition. Therefore, we conducted a phospholipid fatty acid (PLFAs) analysis. As a marker for bacteria we used PLFAs i-C15:0 and a-C-15:0 as well as the C18:2,9c as a marker for fungi. We studied two nutrient poor peatlands in Northern Europe: Lakkasuo (Central Finland) and Degerö Stormyr (Northern Sweden). At all locations cores were taken from adjacent drained (or rewetted) and natural sites. At Lakkasuo drained site, we found a high humification index (HI, after van Post), shown by less plant residuals and a high amount of matrix. For Degerö Stormyr the picture looks different. Above the drained horizon (high HI) peat was light, with a smaller amount of matrix and lots of plant residuals (low HI), like it was also seen in the natural cores. At the drained (and rewetted) sites we found distinct peaks in microbial PLFA concentrations, which correlate to the stable isotope peaks ("turning point”) we found before. At the 15N turning point, in the center of the drained horizon, overall microbial-derived PLFA abundance is also the highest. Furthermore, the overall microbial-derived PLFA abundance is positively correlated with 15N values (r<sup>2</sup>=0.5). Fungi-derived PLFAs are negatively correlated (r<sup>2</sup>=0.4) to 13C. Fungi-derived PLFAs showed the highest amount at the uppermost part of the drained horizon and low amounts in the waterlogged conditions below the drained horizon, whereas 13C showed lowest values at the surface and high values below the drained horizon. Our results suggest, that fungi dominate microbial metabolism in the upper, aerobic peat horizon. Downwards the drained horizon conditions slowly switch to oxygen limitation. Thus, fungal-derived PLFAs decrease whereas bacterial-derived PLFAs are increasing. The highest diversity of microbial-derived PLFAs is indicated by the 15N turning point. Below this point, oxygen is increasingly limited and concentrations of all microbial-derived PLFAs are decreasing down to the 13C turning point and the onset of the permanently waterlogged, anaerobic horizon. Cores from rewetted peatlands show no depth trend of 15N values above the formerly drained horizon and a low amount of microbial-derived PLFAs. Hence, we conclude that stable isotope values reflect microbial metabolism processes, which differ between drained, rewetted and natural peatlands. Additionally, stable isotope patterns reflect a switch in the predominant communities from fungi to bacteria within a drained horizon. Summing up, the PLFA analysis approved that stable isotope measurements can serve as a cost and work efficient monitoring tool for peatland history as well as peatland restoration success.</p>

Mapping Drainage Canals in Southeast Asian Peatlands and their Implications for Peatland Degradation

<p>Drainage canal networks associated with agricultural land use are a major contributor to peatland degradation in Southeast Asia. These canals are used to control water table depth and make the soil suitable for planting, but their presence has the negative impact of drying out peat soils near the ground surface. Drier soils in turn cause elevated fire risk, increased carbon release to the atmosphere, and subsidence. Although canals directly impact local peat hydrology, the effect of drainage intensity (i.e. canal density) in peatlands has not been quantitatively investigated, due to a lack of reliable canal maps in the region.<br><br>In this study, we trained a machine learning model to identify drainage canals and map their density throughout Southeast Asian peatlands using remote sensing imagery. Specifically, a fully convolutional neural network was applied to RGB 5m resolution Basemap imagery from Planet. Training data was generated by hand-labeling canals from satellite images, and validation of canal density was performed via comparison to independently labeled maps. A map of canal density was then produced across ISEA peatlands using images from 2017. We compared canal density with land use type and found that mean canal density is highest in industrial plantations. We also compared canal density with fire occurrence and subsidence data. This new dataset has potential applications for studies of peatland hydrology, land use change, and fire risk.</p>

Spatio-Temporal Visualization of Peatlands Changes

Increased deforestation and draining of peatlands with the started of the drainage occurs quickly makes the availability of peatlands as carbon storage is even more alarming. The presence of peat land conversion greatly affect the hydrological balance of the ecosystem. The conversion of peatland have the massive effect with the increase of drainage constructions for land cultivation needs. This makes the neighborhood unity peat hydrology (KHG) which is wet into dry so prone to burning and experiencing land subsidence. Information of peatland degradation is presented in the spatio - temporal visualization using Space Time Cube (STC). The usability in order to determine the extent of the spatio - temporal visualization can be used by users to obtaining information peatland degradation in terms of effectiveness, efficiency and satisfaction for users. Drainage density built on KHG getting bigger every year with the index of medium density classification. Increasing the number of long-drainage occurs at 119.4934 km per year from 2000 to 2008 and 148.6954 km per year from 2008 to 2012. Based on observations in 12 years has increased the number of distribution Hotspot significantly in February. In May and September the spread of hotspots increased by the average number of hotspots at 15 points per month. The drainage development’s and distribution of hotspot has dominant occurs at the HTI in the KHG Peatland degradation is presented in Visualization spatio-temporal, which visualization is very effective, fairly efficient, and give satisfaction to the users in displaying information peatland degradation in time series.