Hands-On Approach to Foster Paludiculture Implementation and Carbon Certification on Extracted Peatland in Latvia

Abstract

Voluntary carbon markets open horizons for private companies, public institutions, and individuals developing CO₂ removal projects in peatlands to reduce overall carbon footprint. These steps, however, should be in line with appropriate rewetting targets. Therefore, the baseline information about the status of the area must be assessed. Here, we follow the methodology set by the carbon certification program standards, which define the necessary steps for reference conditions assessment. In this study, we practically test the fulfillment of necessary drained peatland baseline evaluation for paludiculture and carbon certification activities. Estimates on the greenhouse gas emission mitigation potential were summarized to define priorities and propose quantifiable measures with suggested paludiculture implementation. Our estimations indicate that rewetting and paludiculture practice on 16.4 ha drained extracted peatland could omit 60.17 t CO₂ annual emissions and instead capture 80.31–120.11 t CO₂ per year. If drainage continues, then it poses a risk of releasing stored carbon from leftover peat deposits into the atmosphere, contributing 52,653.64 t CO₂ to greenhouse gas emissions. Our hands-on approach shows that it is possible for companies to implement rewetting strategies without large EU-level project funding when the conservation and economic aspects are met, thus boosting climate mitigation actions.

1. Introduction

Climate warming and human impacts are thought to be causing peatlands to dry, converting them from sinks to sources of carbon [1]. Countries are encouraged to include peatland conservation, protection, and restoration in their commitment to international climate agreements [2,3]. The challenge is to design sustainable land use, including ecologically sound yet economically viable strategies to conserve biological diversity, carbon storage capacity, and other ecosystem services. The latest initiatives aim to support and scale up the rewetting of drained peatlands as an effective climate mitigation solution by helping to establish peatlands’ carbon offset programs and schemes [4]. Rewetting organic/peat soils and peatland areas allows natural, climate- and economic-friendly usage of these areas through paludiculture (agriculture and forestry on wet and rewetted organic/peat soils and peatlands). Paludiculture is recognized as one of the nature-based solution tools in climate and biodiversity crisis mitigation. This approach includes significant carbon sequestration and long-term storage, which enhances the resilience of carbon stock, thus cooling the climate. Peatland’s ability to sequester carbon is being considered in the national GHG emission assessments and private initiatives as a potential source of revenue to manage carbon-balanced landscapes and pay for ecosystem services [5,6,7].

According to the voluntary carbon market protocols, private companies, public institutions, and individuals can develop CO₂ removal projects, transect carbon credits generated, and reduce their overall carbon footprint. While the European Commission published its legal proposal for the Carbon Removal Certification Framework, aiming at establishing governance and criteria for quantification, additionality and baselines, long-term storage, and sustainability, there is a lack of binding legislation framework at the national levels of the EU [8]. For example, Latvia’s national energy and climate plan for 2021–2030 proposes focusing on afforestation as the main action for decreasing GHG emissions (including afforestation of peat and organic soils) and does not mention voluntary carbon markets or indicate possible carbon certification framework establishment [9]. Indeed, it is surprising because nearly 12% of the territory of Latvia is covered by peatlands, of which a considerable share (~39,500 ha) are so-called degraded and need to be revitalized. At this very moment, all three Baltic countries (Lithuania, Latvia, and Estonia) are one of the largest GHG emitters (>50 MT CO₂ e annually) from degraded peatlands within the EU [10], and there are available voluntary carbon schemes and rewetting and paludiculture possibilities to choose from [11,12,13].

To be able to implement these nature-based solutions through reclamation and recultivation initiatives widely, some critical aspects of extracted peatlands must be considered: (1) Is it realistic for individual enterprises to run peatland restoration without large funding support (e.g., EU LIFE, HORIZON2020, etc., project funding resources)? (2) What baseline information is necessary to obtain for successful rewetting, paludiculture, and carbon certification?

The aim of the current study was to practically test the fulfillment of necessary peatland baseline evaluation for paludiculture and carbon certification activities. Our objectives include the following: (1) assess the feasibility of conducting peatland baseline evaluation for paludiculture and carbon certification activities next to an active peat extraction field in Latvia, North-Eastern Europe; (2) evaluate the credibility and trust of a private enterprise towards nature-based climate mitigation solutions, specifically paludiculture and rewetting, in the context of Latvia’s skeptical peat extraction industry. For this, we selected unused (at least for the last two years) extracted peatland area (16.4 ha) within the active peat extraction field in Latvia (Figure 1). Here, we intentionally aimed to outreach a company working in the peat extraction field. We chose an active company because, in order to rewet peatlands as soon as possible, one should perform these recultivation activities from a bottom-up approach, i.e., from the landowners and managers to the national scale.

2. Materials and Methods

Although the implementation of paludiculture, rewetting, and carbon certification sounds like different activities, they all comprise similar principles regarding field and setting requirements [13,14,15]. Hence, here, we followed the guidance set by the Verified Carbon Standard (VCS; VERRA VM0036 methodology; the most widely used standard for land use projects [16]) and the MoorFutures^® (Germany scheme that has set the standard in Europe [17]). Both standards use the Greenhouse Gas Emission Site Type (GEST) approach for quantification of greenhouse gas (GHG) emission reduction from rewetted drained peatlands in temperate climatic regions. Due to its experimental nature, we outreached the “Laflora” Ltd. (Jelgavas novads, Latvia) peat extraction company, which is open to such science-to-practice activities (e.g., [18,19]) and made an agreement between Lake and Peatland Research Centre to run the project “Vegetation and water monitoring for paludiculture and carbon sequestration projects at “Laflora” Ltd.”. Importantly, the company had no influence on any conclusions or work related to this seven-month project (which lasted from April to November 2023).

For rewetting and carbon certification purposes, it is necessary to set the baseline setting, which will then serve as the reference conditions for further implementation activities. We had the opportunity to work on 16.4 ha large abandoned extracted peatland within the active peat extraction license field (Figure 1). Based on the information the company provided and the site’s reevaluation from the historical satellite image maps, this site was abandoned for four years. Hence, some vegetation had time to develop under these harsh conditions, i.e., highly fluctuating water regimen and the lack of decent surface substrate quality. The area, Kaigu (Veļu) bog, is located in Līvbērze county (17 km to the closest city Jelgava with a population of ~56,000 people). The total area of Kaigu bog is 1546 ha, and the peat extraction takes place on 774 ha. According to the natural resources mining license and reserves of suitable peat in Kaigu bog, the company could extract peat for at least the next ~80 years.

Methodologically, we defined working packages as follows:

(1)

Explore peat thickness (geological coring within 100 × 100 m frame and following interpolation in QGIS) and its characteristics (botanical type, pH and decomposition rate [20], relative composition (loss-on-ignition [21]), and carbon stock [22] analyses with a summary statistics (PAST software v. 4.14 [23]) for nine samples and upscale estimates for the whole area);

(2)

Run water monitoring (six groundwater monitoring wells equipped with TD-Diver (vanEssen Instruments, Delft, The Netherlands) groundwater level loggers);

(3)

Sample groundwater and surface water for chemical (Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃⁻, SO₄²⁻, Cl⁻, N_total, NH₄⁺, N-NH₄⁺, N-NO₂⁻, N-NO₃⁻, P_total, PO₄³⁻) analyses in the accredited laboratory and onsite properties using express tests (pH, electric conductivity, alkalinity, iron concentration; Dist3 and pHep+, HI775, HI96721 Hanna Instruments, Avizieniai, Lithuania);

(4)

Inspect vegetation and landcover (GEST methodology [24,25]);

(5)

Apply photogrammetry (with DJI Phantom RTK drone, 8.8 mm FC6310R camera 5472 × 3648, resolution for pixel 2.41 × 2.41 µm; five ground control points tied with GPS Emlid RS2+ RTK GNSS) to obtain high-resolution landcover and digital elevation model maps (using Agisoft Metashape Professional software (v. 2.0.1.) and QGIS) for landcover zonation;

(6)

Estimate GHG based on GEST [25];

(7)

Make 2D groundwater flow models (QGIS, thinPlateSpline interpolation method on observed water levels + boundary conditions using Lidar data) to understand water dynamics;

(8)

Propose further steps according to the results.

For GHG estimation, we used published emission factors [25], which are indicated in

Table 1. Greenhouse gas emission site (GEST) greenhouse gas emission factors used in current study [25].

GEST No.	GEST Type	Emission Factor
		CO2 (t/CO2/ha/year)	CH4 (t/CO2eq/ha/year)	GWP (t/CO2eq/ha/year)
5	Bare peat dry	16.7	11.5	28.2
6	Bare peat moist	14.4	1.4	15.8
8	Very moist meadows, forbs, and small sedges	−0.5	2.3	1.9
13	Wet, tall sedges reeds	−0.1	8.5	8.4
15	Wet, tall reeds	−2.3	6.3	4.0
20	Open water/ditches	0	2.8	3.0

. To obtain the annual GHG emissions per GEST, the area (ha) was multiplied by the respective emission factors.

Most of the time-consuming work was related to groundwater monitoring and water flow modeling (lasted from April to November 2023). Water monitoring was carried out by four people (installation of cores, waterlogging equipment and monitoring, and data handling). Surveys of geological settings and analyses were performed within three months (April to June 2023). Vegetation was investigated during the vegetation season at the same time when the photogrammetry was carried out (August 2023). GHG was estimated after the GEST method during October and November 2023).

3. Results

Following the requirements for the baseline scenario set by the carbon certification standards, we achieved all the necessary indices for further recultivation activities. Through the geological survey, which was basically an assessment of the leftover peat and the carbon stock it holds, we found that the 16.4 ha area has 151,700 m³ peat reserves (85,690 m³ raised bog peat; 66,010 m³ fen-type peat). The thinnest peat thickness was 0.3 m, and the largest thickness of the peat layer was 2.8 m (Figure 2A). When considering the average carbon concentration for the raised bog peat 554.5 g C/m² (with peat density 113.36 kg/m³; n = 3) and fen type peat 801 g C/m² (with peat density 169.46 kg/m³; n = 6), the total carbon stock in the remaining peat is estimated as high as 14,347.04 t C. When converted to CO₂ emissions, this means that the remaining peat reserves hold a potential of 52,653.64 t CO₂ emissions.

According to the landcover and vegetation communities, six GEST types were identified within the 16.4 ha (Figure 2B,C;

Table 2. Baseline greenhouse gas emissions from 16.4 ha according to the Greenhouse Gas Emission Site Types [25] (GEST: GEST 5—bare peat dry; GEST 6—bare peat moist; GEST 8—very moist meadows, forbs, and small sedges; GEST 13—wet tall sedges reeds; GEST 15—wet tall reeds; GEST 20—open water/ditches). Carbon dioxide (CO₂), methane (CH₄), and global warming potential (GWP) indicated.

GEST	ha	CO2 (t CO2/year)	CH4 (t CO2e/year)	GWP (t CO2e/year)
5	2.15	35.9	24.72	60.63
6	2.77	39.88	3.87	43.76
8	0.03	−0.015	0.069	0.057
13	3.76	−0.376	31.96	31.584
15	6.62	−15.23	41.706	26.48
20	1.07	0	2.996	3.21
TOTAL	16.4	60.159	105.321	165.721

): (1) GEST 5 (bare peat dry (OL) 2.15 ha; (2) GEST 6 (bare peat moist (OL) 2.77 ha; (3) GEST 8 (very moist meadows, forbs and small sedges) 0.03 ha; (4) GEST 13 (wet tall sedges reeds) 3.76 ha; (5) GEST 15 (wet tall reeds) 6.62 ha; and (6) GEST 20 (open water/ditches) 1.07 ha. The total emissions (following GEST emission factors established by [25]) from 16.4 ha are as high as 165.502 t CO_2eq/year (CO₂ = 60.159 t CO₂/year; CH₄ = 105.321 t CO_2eq/year; GWP = 165.721 CO_2eq).

Electric conductivity measurements reveal values (µS/cm) 150 for ditch water, and it ranged from 388 to 866 (average 746.4) in groundwater. The pH in a ditch was 6.53, and it ranged from 6.71 to 7.19 (average 6.908) in groundwater. Alkalinity (ppm) for ditch water was 34, but for groundwater, it was from 192 in core No.5 up to 442 in core No.6 and even >500 (above the maximum detection limit) in cores No.2 and No.3. Total iron concentration (mg/L) in ditch water was 2.22, and in three out of five groundwater samples showed 2.41, >5 (above the maximal detection limit) and 4.1. Groundwater is dominated by calcium and magnesium cations and bicarbonate anions, while ditch water is also dominated by bicarbonate anions, but its concentration is 11 times lower than in groundwater. The groundwater sample contains 1.85 mg/L total nitrogen, which is primarily in the form of ammonium ions (1.68 mg/L N-NH₄⁺), indicating relatively high nutrient presence, whereas the ditch water sample contains much lower concentrations (0.28 mg/L N-NH₄⁺). The phosphorus concentration in groundwater was below the detection limit and at the detection limit in surface ditch water (0.006 mg/L).

Significant changes in the groundwater system and water flow directions have been observed throughout the observation period (Figure 3). In June and July, a decrease in groundwater levels was mainly due to evapotranspiration, as observed by the diurnal variations in groundwater levels. The groundwater flow distribution for the beginning of June shows that the groundwater flows towards the drainage ditches. The highest absolute levels occur in the vicinity of core No.5 (urb5), which is defined by the natural peatland remaining to the west of it, which is characterized by a hypsometrically higher relief (Figure 3). Late July is characterized by the lowest groundwater levels of the whole observation period due to the hot summer and intense evapotranspiration (both from the ground/water surface and transpiration through plants). The lowest groundwater levels were observed in well No.3 (urb3), with a drop of groundwater level just 0.49 m a.s.l. or 2.34 m below the surface, while the water level in the ditch was higher (1.42 m above the sea level). At the end of October, groundwater levels recovered because of autumn rainfall, and groundwater flow routes recovered with the main flow direction towards the ditches. Over the observed period, the water table in the central part of the southern study field changed significantly with relative groundwater level variations up to 1.83 m, while the northern field showed more stable groundwater level conditions (still groundwater level changes up to 0.79 m though).

During the reporting of the results, continuous bilateral communication with the company was performed to aid in additional explanation to the reports for each working package. For future reference, one should allocate additional working hours for communication as such projects are not self-explanatory for the companies. Before one can proceed with the actual implementation of rewetting or paludiculture practices, it is important to see the reference conditions. Our results and gained experience with the current project show that at least half a year is necessary to obtain basic information for paludiculture and carbon certification projects. Total costs to estimate peatland baseline conditions for paludiculture and/or carbon certification activities can range from 1300 to 4000 EUR/ha (depending on the complexity of the site and wage for experts). Costs are estimated considering all steps included in the current study. This does not include further modeling and possible implementation projects.

4. Discussion

Each method applied in the current study helped us decide which paludiculture can be potentially grown on extracted peatland. The water level showed that it is variable, and only certain species can be grown under these conditions. Water chemistry (high alkalinity) showed that Sphagnum moss can be challenging to grow here [26]. Theoretically, each method can be slightly modified, and a relevant analog might be selected. However, from the carbon certification point of view, the methods are determined by the VERRA and MoorFutures certification. Hence, only minor variations in the methodology approach can be considered in future relevant projects.

Our results indicate unexpected groundwater chemistry and properties for a particular peatland setting where alkaline and nutrient-rich waters are below the thin peat layer. These groundwaters will eventually define further success for the implementation of paludiculture due to their location near the surface. In our study site, the groundwater table fluctuates even up to 1.83 m, and it has been shown that under such conditions, more GHGs are emitted than under stable hydrological conditions [27,28,29]. Hence, highly variable groundwater levels aid the need for recultivation actions, which require thoughtful planning to ensure necessary hydrological conditions, i.e., stable water level close to the peat surface according to the paludiculture definition (10–30 cm from the surface). Extracted field maintenance (surface leveling, ditch closure) with the aim of obtaining constant hydrological conditions should be planned for successful paludiculture implementation and GHG with low global warming potential [30,31]. At the same time, one should be aware that by doing so, novel peatland ecosystems are established, which cannot be directly assumed as natural sites [32].

Based on the results (groundwater chemistry, water level, peat type, and thickness), several paludiculture taxa options are possible in particular circumstances: reed (Phragmites australis), reed canary grass (Phalaris arundinaceae), cattail (Typha angustifolia/latifolia), or sedges/wet meadow [11]. Because the water level in the northern part of the area (9.016 ha) has lower fluctuations and can be managed to keep closer to the peat surface (Figure 3), wet sedges [30] could be established, capturing 54.1 t CO₂ annually. In the southern part area (7.384 ha), reed canary grass can be a possible option for paludiculture. Reed canary grass [24,28] could capture a total of 26.213 t CO₂ annually. Even higher benefits can be gained, with common reeds reaching 66.01 t of CO₂ captured annually. Other possible scenarios can be considered from both the biodiversity and greenhouse gas (GHG) perspective (e.g., [11,33]). Rewetting and paludiculture thus would omit the current 60.17 t CO₂ annual emissions and instead, capture 80.31–120.11 t CO₂ per year (total benefit omitted 140.48–180.28 t of CO₂ annually from 16,4 ha drained peatland). Although neglected methane emissions are considered under rewetting conditions due to long-term effects [31], these values might range from negative to positive effects on climate change [33,34,35]. If very moist meadows or small sedges and common reeds are planted during rewetting in 16.4 ha, potential total CH₄ emissions [25] could reach even up to 67 t CO_2eq/year. Precise indices of CH₄ can be assessed only through the monitoring of GHG after the rewetting. Lately, there is now a general understanding that it is not only one GHG (CO₂, CH₄, or N₂O), but the total effect on climate must be considered. Hence, the global warming potential (GWP) of GHGs should be considered to avoid making decisions based solely on short-period benefits that may overlook the long-term climate cooling effect [30,35].

Large emissions from drained sites also mean significant mitigation potential by rewetting. Therefore, available estimates on the GHG mitigation potential were summarized to define future priorities and propose quantifiable measures under paludiculture implementation (both climate and economic profit). By implementing recultivation measures in this area, there is a significant opportunity to enhance its function as a carbon sink. Recultivation in this context can lead to several beneficial outcomes. Firstly, the retention of existing carbon stored in peat on the total investigation site, which, by our estimates, comprises 14,347.04 t C. If drainage continues, then it poses a risk of releasing stored carbon into the atmosphere, contributing 52,653.64 t CO₂ to the GHG. Secondly, aboveground biomass of reed canary grass, if harvested, could bring 7.9–13.2 t ha⁻¹ that can be used for pellet production [19]. Usage of aboveground biomass is crucial to meet the overall climate benefits, as has been shown by the life cycle assessment for paludiculture practice [36].

Latvian peatland extracting companies are bound by a given mining license, which mandates that, after peat extraction, they recultivate peatland either to waterbody, afforestation, or revitalization back to natural peatland status. Hence, in such cases, no additionality applies, and no carbon credits can be generated. Only the projects of peatland recultivation where there is no legal obligation to restore peatland as a natural bog ecosystem (e.g., defined by the license or the site is abandoned degraded peatland) might be an option. According to the natural resource mining license, a particular peat company could extract peat in the current area (next to the studied area) for at least the next ~80 years. Only after a complete extraction could full recultivation theoretically take place. Given that the company is ready for rewetting ~80 years earlier than required by the lease and legislation, the additionality principle could apply. Without rewetting actions, GHG emissions from exposed and drained fields will be released over the next ~80 years, and the remaining peat will mineralize and decompose.

All ongoing activities with the aim of generating carbon units are welcome from a climate mitigation point of view. However, unclear aspects are related to carbon double counting and lack of clarity about the organic soils and LULUCF at the national level. The European Union is setting the stage for a carbon certification framework, which will most likely include principles of taxonomy (EU taxonomy). Until Latvia develops its own carbon certification schemes, all the actions related to rewetting and paludiculture for offsetting, insetting, and carbon certification projects shall follow the existing voluntary carbon market standards and upcoming EU regulations.

5. Conclusions

Our hands-on approach shows that it is possible for companies to implement rewetting strategies without large EU-level project funding when the conservation and economic aspects are met. After evaluating the baseline scenario for 16.4 ha large extracted peatland, we clarified that under the current situation, there are substantial CO₂ (60.17 t CO₂) and CH₄ (105.321 t CO_2e) annual emissions, and the annual global warming potential is 165.721 t CO_2e. In addition, if the site’s drainage continues, then it poses a risk of releasing stored carbon from leftover peat deposits into the atmosphere, contributing 52,653.64 t CO₂ to greenhouse gas emissions. Rewetting and paludiculture practice on 16.4 ha drained extracted peatland could potentially omit 60.17 t CO₂ annual emissions and instead capture 80.31–120.11 t CO₂ per year. Assessment of the baseline conditions sets a stage for the bog recultivation, thus representing a proactive approach to both preserving existing carbon stores and enhancing future carbon sequestration. This dual strategy is an effective way to combat climate change and contributes positively to global efforts to reduce atmospheric CO₂ levels.