Stock Biomass Research Articles

Motor-manual release changes carbon distribution in soil and tree biomass pools in the short term

Despite offering multiple ecosystem services, such as their ability to sequester carbon (C), regenerating mixedwood boreal forests are often only managed to increase their coniferous part by controlling their competition, impacting the ecosystem C stocks. The aim of this study was to compare the short-term effect of motor-manual release treatments of variable intensities: broadcast brushing (brushing), release-from-below (RFB) and crop-tree release (CTR) on carbon stocks in soil (SOC) and live biomass (aboveground and root C stocks). The stands treated by brushing had twice as much SOC stocks than in the other stands, at the 5- to 10 cm depth. RFB treatment kept the largest aspen stems in the stands and retained enough total live biomass to compensate for the initial loss. Despite being similar in intensity, stands treated with RFB had more than twice the amount of live biomass than stands treated by brushing. Overall, total C stocks (SOC and live biomass) did not change between the stands but the distribution among the different C pools did, with the live biomass being the most impacted by the treatments. The design of the RFB treatment seemed promising to mitigate C loss during early forest operations while still controlling fast-growing competitors.

Ecosystem Changes Caused by Hydrological Change are Associated with Population Decline in a Formerly-Common Grazing Herbivore

Few ecosystems are more sensitive to hydrological change than seasonally-flooded wetlands. Here, we investigate how changes in hydrological regimes caused by the construction of two dams have contributed to large changes in the structure and dynamics of the Kafue Flats, an internationally-important, partially-protected wetland ecosystem in Zambia. We use historical (1970) and contemporary (2013) data to describe changes in hydrology due to dam operations, and to compare the areal extent, distribution, and composition of the major wetland and dryland habitats in the pre- and post-dam periods. To understand the seasonal dynamics of the ecosystem and how these dynamics influence the seasonal movement and use of the ecosystem by the dominant grazing herbivore, the endangered Kafue lechwe, we combine data on annual hydrological variation with spatially- and/or temporally-explicit quantitative estimates of: (1) grass biomass and nutrient stocks, (2) distribution of lechwe across habitats, and (3) lechwe nutritional status. The operation of the dams has reduced hydrological variation, causing a loss of more than 50% of seasonally-flooded grasslands and probably promoting woody encroachment in some habitats. Our results demonstrate that Kafue lechwe is highly dependent on these seasonally-flooded grasslands during the dry season, when their nutritional status is otherwise critically low. In combination, we hypothesize that changes in the flooding regime driven by dam construction precipitated ecosystem-level changes that—together with other factors—may have contributed to a rapid historic, as well as ongoing decline in the lechwe population. Our study highlights potential consequences of the spatio-temporal homogenization of a previously highly variable ecosystem.

Labile Soil Carbon Heterogeneity Driven by Consumer Engineering of Aboveground Structure in a Kenyan Savanna

Aboveground ecosystem structure moderates and even confers essential ecosystem functions. This includes an ecosystem’s carbon dynamics, which are strongly influenced by its structure: for example, tropical savannas like those in central Kenya store substantial amounts of carbon in soil. Savannas’ belowground allocation of carbon makes them important for global carbon sequestration, but difficult to monitor. However, the labile soil carbon pool is responsive to changes in ecosystem structure and is thus a good indicator of overall soil organic carbon dynamics. Kenya’s savanna structure is controlled by belowground ecosystem engineers (termites), ambient weather conditions, and the aboveground engineering influences of large-bodied, mammalian consumers. As a result, climate change and biodiversity loss are likely to change savannas’ aboveground structure. To predict likely outcomes of these threats on savanna soil carbon, it is critical to explore the relationships between labile soil carbon and ecosystem structure, local climate, and mammalian consumer community composition. In a large-scale, long-term herbivore exclosure experiment in central Kenya, we sampled labile carbon from surface soils at three distinct savanna structural elements: termite mounds, beneath tree canopies, and the grassland matrix. In one sampling year, we measured total extractable organic carbon (TEOC), total extractable nitrogen (TEN), and extractable microbial biomass for each sample. Across three sampling years with varying weather conditions, we measured rate of labile soil carbon mineralization. We quantified areal coverage of each structural element across herbivore community treatments to estimate pool sizes and mineralization dynamics at the plot scale. Concentrations and stocks of soil TEOC, TEN, and microbial biomass were driven by the structural element from which they were sampled (soils collected under tree canopies generally had the highest of each). Large-bodied herbivore community composition interacted variably with concentrations, stocks, and carbon mineralization, resulting in apparently compensatory effects of herbivore treatment and structural element with no net effects of large herbivore community composition on plot-scale labile carbon dynamics. We confirmed engineering of structural heterogeneity by consumers and identified distinct labile carbon dynamics in each structural element. However, carbon and nitrogen were also influenced by consumer community composition, indicating potentially compensatory interacting effects of herbivore treatment and structural element. These results suggest that one pathway by which consumers influence savanna carbon is by altering its structural heterogeneity and thus the heterogeneity of its plot-scale labile carbon.

Soil and Site Productivity Effects on Above- and Belowground Radiata Pine Carbon Pools at Harvesting Age.

Pinus radiata D. Don is the most widely planted forest species in Chile, making it crucial to understand carbon pools in adult plantations. This study aimed to evaluate the effect of soil type and site productivity on the total carbon stock in adult radiata pine plantations, considering sites with contrasting water and nutrient availability. We selected 10 sites with sandy and recent volcanic ash soils, representing a productivity gradient. At each site, three 1000 m2 plots were established to quantify the carbon stock of total biomass using allometric equations and in situ carbon assessments of the forest floor and mineral soil (up to 1 m deep). The results indicated significantly higher carbon stocks in the mineral soil of recent ash sites (281.4 Mg ha⁻1) compared to sandy soils (139.9 Mg ha⁻1). The total site carbon was also higher in recent ash (473.2 Mg ha⁻1) than in sandy sites (330.9 Mg ha⁻1). A significant relationship was found between stand productivity and soil organic carbon (r2 = 0.88), as well as total carbon stock (r2 = 0.91) when considering soil type. These findings highlight the importance of including assessments up to 1 m depth and developing soil type and productivity models to improve site carbon stock estimates.

Spatiotemporal variability in the population demography of the golden kelp, Laminaria ochroleuca (Phaeophyceae), at its leading range edge

ABSTRACT Ocean warming is driving poleward range shifts for many marine species. For foundation organisms that underpin the wider ecosystem, such as canopy-forming seaweeds, shifts in distributions or population demography can have widespread ecological consequences. The warm water kelp, Laminaria ochroleuca, is found towards its leading edge in Plymouth Sound (southwest England, UK), where it has proliferated in recent years, partially replacing the cool-water congeneric species, L. hyperborea, at some wave-sheltered locations. To determine how ecosystem dynamics have changed due to this substitution and to benchmark population structure, monthly surveys were conducted of L. ochroleuca populations at three sites over 10 months. Canopy-forming L. ochroleuca sporophytes were recorded in all months at all sites, in densities of up to ~8 individuals m‒2, indicating that this species is now a conspicuous space occupier within this ecosystem. Blade length, weight and fertility followed clear seasonal patterns peaking during late spring/early summer and rapidly declining in autumn/winter. Between-site variability was also observed, with greater densities, blade lengths/widths and standing stock biomass at the most wave-sheltered but tidally influenced site. The most abundant herbivore associated with L. ochroleuca was the blue rayed limpet, Patella pellucida, which was predominantly found in summer months and in greater abundance than reported values for other kelps in the region. Our survey wide estimates of carbon standing stock ranged from 408 ± 67 to 1006 ± 181 g C m‒2 across sites, with a regional mean of 615 g C m‒2, which was in line with previous estimates for the congeneric L. hyperborea at nearby sites. Overall, the most detailed demographic assessment of L. ochroleuca to date is provided, which allows for a greater understanding of its ecological role within the wider temperate ecosystem and serves as a robust baseline against which to detect future ecological changes.

Assessment of Ecosystem Health and Carbon Stocks in the Seagrass Meadows of Mengiat Beach, Bali, Indonesia

Seagrass meadows provide many important ecosystem services. They are now recognized as blue carbon ecosystems that are crucial in the mitigation of global climate change. This study was conducted at Mengiat Beach in Bali, Indonesia, where there are extensive seagrass meadows along the shorelines, but also considerable anthropogenic activity that pose threats to the ecosystem. The objectives of this study were to: (1) describe the seagrass community at Mengiat Beach; (2) assess the health status of the seagrass ecosystem; and (3) estimate carbon stocks stored within the ecosystem. Vegetation analysis was conducted to describe the seagrass community in terms of density, cover, biomass and species importance. Spatial Sentinel-2 satellite data with unsupervised classification was used to determine the extent of seagrass meadows. Carbon stocks in sediment and biomass were estimated using the loss on ignition method. The seagrass community at Mengiat Beach consists of at least five different species, dominated by Cymodocea rotundata. The meadows are characterized by high density (588 ind.m-2) and good cover (60.7%). They are considered healthy, with good ecological quality, as indicated by a SEQI (Seagrass Ecological Quality Index) of 0.69. The seagrass ecosystem stores a significant amount of carbon, with 99.23% of it stored in sediment. Total carbon stock in sediment and seagrass biomass is estimated at 133.39 MgC.ha-1. When extrapolated to the total seagrass area of 43.21 ha, the meadows at Mengiat Beach store a total carbon stock of 5.76 GgC, highlighting their potential as high-carbon reservoirs and importance in climate change mitigation efforts.

Coastal carbon storage in degraded, natural, and restored mangrove ecosystems of Guyana

Mangroves are among the most carbon-rich forests in the tropics due to their capacity to sequester and store carbon within their ecosystems. However, the combination of natural and human-induced phenomena causes changes in these ecosystems which can affect the flow of carbon within them. In the wet and dry seasons, we examined and compared the carbon content stored in aboveground biomass, standing litter, and soil in natural, degraded, and restored mangrove ecosystems located along the Guyana coastline. During a one-year period, a point-centred quartered method was used for tree sampling, while a randomised block design was used for standing litter and soil sampling. Our study revealed that the natural ecosystems exhibited higher carbon pool levels (29.58–35.14 Mg ha−1), followed by the degraded ecosystems (30.49–32.27 Mg ha−1), and then the restored ecosystems (22.81–27.63 Mg ha−1). Significant differences were documented only in carbon found in aboveground biomass between ecosystem states, particularly within the natural ecosystems, due to the presence of mature trees with larger diameters at breast height. While seasonal fluctuations exist between the various carbon pools, particularly within the degraded ecosystems, our findings yielded insignificant differences between seasonality for all three carbon pools. However, linear mixed-effect models revealed that seasonality may influence the soil and standing litter carbon concentrations to an extent. Positive correlations in the restored ecosystems suggest that the larger carbon stocks in aboveground biomass may be associated with carbon stocks in soil and standing litter, unlike the negative correlations seen in the natural and degraded ecosystems. Our study provides some evidence that the overall carbon storage capacity of mangroves is influenced by the current state of their ecosystem, that is, ecosystems characterised by minimum disturbances may possess a greater capacity for carbon storage in comparison to ecosystems that are currently experiencing or have recovered from disturbances.

Drivers of biomass stocks and productivity of tropical secondary forests.

Young tropical secondary forests play an important role in the local and global carbon cycles because of their large area and rapid biomass accumulation rates. This study examines how environmental conditions and forest attributes shape biomass compartments and the productivity of young tropical secondary forests. We compared 36 young secondary forest stands that differed in the time since agricultural land abandonment (2.3-3.6 years) from dry and wet regions in Ghana. We quantified biomass stocks in living and dead stems, roots, and soil, and aboveground biomass and litter productivity. We used structural equation models to evaluate how macroclimate, soil nutrients (N, P), and forest attributes (structure, diversity, and functional composition) affect ecosystem functioning. After three years of succession, tropical wet forests stored on average 115 t biomass ha-1 (the sum of aboveground living and dead biomass, belowground fine root biomass, and soil organic matter), and dry forests stored 99 t ha-1. These values represent 31% (in the wet forest) and 39% (in the dry forest) of the biomass compared with neighboring old-growth forests. The majority of forest ecosystem biomass was stored in the soil (70%) and aboveground living vegetation (25%). Macroclimate strongly shaped forest attributes, which in turn determined biomass stocks and productivity. Soil phosphorus strongly increased litter production and soil organic matter, confirming that it is a limiting element in tropical ecosystems. Tree density and species diversity increased forest biomass stocks, suggesting crown packing and complementary resource use enhance forest functioning. A more conservative trait composition (high wood density) increased biomass stocks but reduced productivity, indicating that quantity, identity, and quality of species affect ecosystem functioning.

Tree species controls over nitrogen and phosphorus cycling in a wet tropical forest

AbstractWet tropical forests play an important role in the global carbon (C) cycle, but given current rates of land‐use change, nitrogen (N) and phosphorus (P) limitation could reduce productivity in regenerating forests in this biome. Whereas the strong controls of climate and parent material over forest recovery are well known, the influence of vegetation can be difficult to determine. We addressed species‐specific differences in plant traits and their relationships to ecosystem properties and processes, relevant to N and P supply to regenerating vegetation in experimental plantations in a single site in lowland wet forest in Costa Rica. Single‐tree species were planted in a randomized block design, such that climate, soil (an Oxisol), and land‐use history were similar for all species. In years 15–25 of the experiment, we measured traits regarding N and P acquisition and use in four native, broad‐leaved, evergreen tree species, including differential effects on soil pH, in conjunction with biomass and soil stocks and fluxes of N and P. Carbon biomass stocks increased significantly with increasing soil pH (p = 0.0184, previously reported) as did biomass P stocks (p = 0.0011). Despite large soil N pools, biomass P stocks were weakly dependent on traits associated with N acquisition and use (N2 fixation and leaf C:N, p < 0.09). Mass‐balance budgets indicated that soil organic matter (SOM) could supply the N and P accumulated in biomass via the process of SOM mineralization. Secondary soil P pools were weakly correlated with biomass C and P stocks (R = 0.47, p = 0.08) and were large enough to have supplied sufficient P in these rapidly growing plantations, suggesting that alteration of soil pH provided a mechanism for liberation of soil P occluded in organo‐mineral soil complexes and thus supply P for plant uptake. These results highlight the importance of considering species' effect on soil pH for restoration projects in highly weathered soils. This study demonstrates mechanisms by which individual species can alter P availability, and thus productivity and C cycling in regenerating humid tropical forests, and the importance of including traits into global models of element cycling.

Drivers of growth in strong year classes of the deepwater redfish (Sebastes mentella) population from the Gulf of St. Lawrence derived from otolith increment-based growth chronologies.

The case of the deepwater redfish (Sebastes mentella) in the Gulf of St. Lawrence (GSL) is a compelling example of drastic fluctuations in annual recruitment strength, characteristic of spasmodic stocks. After three decades of low abundance, the emergence of three consecutive strong year classes in 2011-2013 resulted in an unprecedented increase in biomass. In spasmodic stocks such as GSL redfish, strong year classes sustain both the biomass and catch for decades. Therefore, understanding the growth dynamics of these cohorts is essential. In the present study, we reconstructed the annual growth rates of redfish using otolith increment-based annual chronology and investigated the drivers of growth variation in redfish strong year classes of the early 2010s and early 1980s. Stock biomass was identified as the main extrinsic driver of redfish growth, suggesting intense competition for food at high conspecific density. Warming of deep waters in the GSL, where adult redfish settle, positively correlated with individual growth. However, recent warming of the cold intermediate layer showed a negative correlation with redfish growth, likely related to the shrinking of the habitat this water mass provides for various redfish cold-water prey rather than to a direct effect of temperature. Reconstruction of redfish annual growth trajectories from birth to capture emphasized the importance of carryover effects in the growth potential of strong year classes. This work provided an important first outlook of the factors driving growth variation in GSL redfish spasmodic stock and explored midterm consequences of density-dependent pressures on biological parameters of the population.

COMPARATIVE METHODS OF BIOMASS AND CARBON STOCK ASSESSMENT OF SOME SELECTED TREE SPECIES USED FOR CHARCOAL PRODUCTION IN THE GUINEA SAVANNA ECOLOGICAL ZONE OF NIGERIA

Non-destructive method of above-ground biomass (AGB) and carbon stock assessment is the most frequently used method to quantify the amount of carbon sequestered by the trees/vegetation because it involves assessing the biomass and carbon without cutting down the tree species. However, to validate the claim of the biomass and carbon stock of the non-destructive method, the destructive method must be employed to ascertain the real biomass and carbon stock by harvesting the tree species. This study incorporated both the destructive and non-destructive biomass and carbon stock assessment methods. The results of the independent t-test (t = 3.351, p = 0.00475) between the two methods revealed that the destructive method had higher biomass (M=0.425, SD=0.14313) than the non-destructive method (M=0.2338, SD=0.07463) at an alpha value of 0.05. The ANOVA among the tree species harvested for charcoal production further revealed a significant difference in the mean biomass, where Vitellaria paradoxa and Parkia biglobosa had the highest. At the same time, Pterocarpus erinaceus and Daniellia oliveri recorded the least biomass and carbon stock of the tree species used for charcoal production in the study area.

Cross-modal fusion approach with multispectral, LiDAR, and SAR data for forest canopy height mapping in mountainous region

The study introduces a technique for integrating multispectral, LiDAR, and Synthetic Aperture Radar (SAR) data within a machine-learning (ML) framework. By leveraging ML models, including Random Forest (RF), Gaussian Process Regression (GPR), and k-Nearest Neighbors (k-NN), successfully provides a comprehensive methodology for mapping forest canopy height (CH) and analyzes seasonal changes from 2019 to 2023 in the mountainous region of Vodno Mountain, North Macedonia. The RF model achieved the highest accuracy (R2 = 0.91, RMSE = 1.2 m), outperforming the other models when trained with Aerial LiDAR data. The forest CH models were validated against field measurements, Aerial LiDAR, and Global Ecosystem Dynamics Investigation (GEDI) data, confirming the accuracy of the approach and showing solid correlations between predicted and observed CH values. This research is significant due to its innovative approach to forest CH modeling in a region with minimal prior studies. Integrating multi-source data enables more accurate and detailed CH mapping, essential for monitoring forest biomass and carbon stocks, detecting forest disturbances, and assessing future forest management activities.

Edge effect and species richness modulate biomass stocks and change over time in secondary forest fragments in the subtropical Atlantic Forest

ABSTRACT Background Above-ground biomass (AGB) and its temporal dynamics are key parameters of forest ecosystems, related to their resilience and capacity to fix atmospheric carbon. AGB is related to species richness, composition, forest structure, soils and climate. In human-modified landscapes, fragmentation and human pressure may change the nature of these relationships. Aims Our aim was to quantify how species richness and composition, leaf area index, and edge effect were related to biomass stocks and growth in fragmented sub-tropical secondary forests. Methods We tested the relationship between leaf area index, tree species richness and composition, edge effect and AGB stocks in secondary forest stands in the Atlantic Forest using multiple linear models on data from 104 sites. Results Our results show that biomass stocks were related to species richness, distance to forest edge and the interaction of both (R2 = 0.25; p < 0.05). Biomass change showed positive relationships with pioneer species richness and distance to edge, and negative relationship with the interaction of total species richness and distance to edge (R2 = 0.15; p < 0.05). Conclusion Edge effect can affect AGB dynamics directly and indirectly, by weakening the positive effects of species richness and composition on biomass. AGB loss at some sites suggests that some fragments are under chronic disturbance or may be experiencing delayed mortality due to fragmentation.

Carbon farming for climate change mitigation and ecosystem services – Potentials and influencing factors

Carbon Farming (CF) decreases atmospheric CO2 concentrations by increasing carbon stocks in soils and biomass. In addition to mitigating climate change, CF measures provide co-benefits through the supply of additional ecosystem services (ES). Integrating such benefits into a comprehensive assessment may increase the attractiveness of CF measures, increase adoption rates, and ultimately benefit climate and ecosystems. However, site-specific and measure-specific characteristics influence the impacts of CF measures. A comprehensive overview over CF impacts is lacking. We therefore analyzed six CF measures on cropland in the European temperate zone: (1) cover cropping, (2) introducing legumes or semi-perennial crops into crop rotations, (3) conversion to short rotation coppice, (4) agroforestry, (5) afforestation of marginal cropland, and (6) partial rewetting of drained organic soils. Through a structured literature review, we derived on-site climate change mitigation potentials, impacts on the supply of ES, and economic trade-offs, as well as influencing factors causing spatial heterogeneities. Our results show that the climate change mitigation potential varies strongly between and within CF measures. All measures can boost the supply of regulating ecosystem services, while trade-offs exist mainly with provisioning services and economic returns. Spatially heterogeneous effects in ES supply depend on local ES demand. As proof of concept, we mapped expected beneficial ES effects from 4 selected ES positively impacted by the measure (4) agroforestry in a GIS environment for Germany, as well as opportunity costs as an economic trade-off. The results suggest that strong co-benefits can be expected in areas where opportunity costs are high. Moreover, the CF measures with the highest climate change mitigation potential also imply the highest systemic change of the farm system. This constitutes a strong economic hurdle to implementation. We argue that payments for ES are needed to incentivize CF adoption and harness the beneficial effects on climate and ecosystems. Our findings provide a comprehensive view on the effect of CF measures and may support effective European climate change mitigation policy.

Harnessing Biomass and Blue Carbon Potential: Estimating Carbon Stocks in the Vital Wetlands of Eastern Sumatra, Indonesia

Global warming is a critical factor driving climate change, impacting every aspect of life on Earth. The escalating concentration of greenhouse gasses in the atmosphere, the primary contributor to global warming, necessitates immediate action through effective climate mitigation strategies. This study aimed to quantify the biomass and blue carbon stocks in the eastern coastal mangrove forests of North Sumatra and Aceh Provinces in Indonesia, focusing on key sites in Langkat, Deli Serdang, Batu Bara, Tanjung Balai, and Aceh Tamiang Regencies. We measured carbon stock in three carbon pools: biomass (above and below ground), necromass, and soil. By analyzing tree stands using parameters such as tree height and diameter at breast height within circular plots (7 m in radius, 125 m apart), we gathered fundamental data on forest structure, species composition, and above- and below-ground biomass. Additionally, we collected soil samples at various points and depths, measuring the amount of wood, stems, or branches (necromass) that fell to or died on the forest floor. Data were collected in plots along a line transect, comprising three transects and six circular plots each. Sixteen diverse mangrove species were found, demonstrating rich mangrove biodiversity. The mangrove forests in the five regencies exhibited significant carbon storage potential, with estimated average above-ground carbon ranging from 96 to 356 MgC/ha and average below-ground carbon from 28 to 153 MgC/ha. The estimated average deadwood carbon varied between 50 and 91 MgC/ha, while soil carbon ranged from 1200 to 2500 MgC/ha. These findings underscore the significant carbon storage potential of these mangrove forests, highlighting their importance to global carbon cycling and climate change mitigation. This research contributes to a broader understanding of mangroves as vital blue carbon ecosystems, emphasizing the necessity of conservation efforts such as forest restoration and rehabilitation to enhance their role in stabilizing coastal areas and improving global climate resilience.

Expected improvements in precision when integrating opportunistic close-kin mark-recapture data into fisheries stock assessments

Close-Kin Mark-Recapture (CKMR) sampling, by providing information on abundance and survival rates (and potentially other quantities), offers a promising new data source for fisheries stock assessments. Sample design in order to achieve a desired precision is somewhat straightforward in simple CKMR models; however when integrated within a full stock assessment model with many other data sources, the value of the data (in terms of a reduction in uncertainty of model estimates) is less clear. Herein I demonstrate, using self-test simulations, the expected improvements in precision and accuracy of derived quantities and estimated parameters within statistical catch-at-age models when opportunistic CKMR sampling is conducted and the data integrated within the assessment. By opportunistic CKMR sampling I mean to describe the genetic sampling of individuals that comprise the age composition data, such that increases in CKMR sampling would also increase the age composition samples (and vice versa). I examine the expected improvements across three life history types (cod-like, flatfish-like, and sardine-like) and different amounts of data available to the assessment, including the uncertainty and inclusion of an abundance index and the sample size and time series length of CKMR and age composition samples. Results suggest CKMR data can provide considerable improvements in accuracy and precision of spawning stock biomass at the end of the time series and parameters defining natural mortality and scale of the population, provided an adequate annual sample size is collected relative to the spawning abundance of the stock during the period of CKMR inference. The time-series length of CKMR data and uncertainty or inclusion of an abundance index played a much more moderate role in how much improvement CKMR data provided over models fit without CKMR. This result was likely a function of the model being privy to an effectively known catch time series and known steepness, allowing it to estimate stock scale and trend reasonably well without CKMR data given informative composition data. I recommend simulation analyses including stock assessments as estimation models be carried out for those considering routinely collecting and integrating CKMR data into fisheries stock assessments.

Soil community history strengthens belowground multitrophic functioning across plant diversity levels in a grassland experiment

Biodiversity experiments revealed that plant diversity loss can decrease ecosystem functions across trophic levels. To address why such biodiversity-function relationships strengthen over time, we established experimental mesocosms replicating a gradient in plant species richness across treatments of shared versus non-shared history of (1) the plant community and (2) the soil fauna community. After 4 months, we assessed the multitrophic functioning of soil fauna via biomass stocks and energy fluxes across the food webs. We find that soil community history significantly enhanced belowground multitrophic function via changes in biomass stocks and community-average body masses across the food webs. However, variation in plant diversity and plant community history had unclear effects. Our findings underscore the importance of long-term community assembly processes for soil fauna-driven ecosystem function, with species richness and short-term plant adaptations playing a minimal role. Disturbances that disrupt soil community stability may hinder fauna-driven ecosystem functions, while recovery may require several years.

Influence of Soil Texture on Carbon Stocks in Deciduous and Coniferous Forest Biomass in the Forest-Steppe Zone of Oka–Don Plain

Forests play a crucial role in climate change mitigation by acting as a carbon sink. Understanding the influence of soil properties on carbon stocks in forests is essential for developing effective forest management strategies. The aim of the study was to assess the impact of soil texture on carbon stocks in the biomass of deciduous and coniferous tree stands of a forest-steppe ecotone. Soil samples were collected from 55 soil pits, and forest inventory data were obtained from eight permanent sample plots. The results showed that the distribution of mechanical particles in soils, particularly the stocks of silt and clay, significantly influenced the accumulation of carbon in tree stands. The stock of silt and clay was shown to increase with an increase in the diversity of tree species in forests and carbon stocks in forest stands. While soil organic carbon stocks did not exhibit a clear relationship with tree stand carbon stocks, a strong positive correlation (r = 0.802, p &lt; 0.05) was found between the stocks of fine particles in the 2 m root-inhabited soil layer and the carbon stocks in tree biomass. The study provides a classification of forest types based on soil texture, which can facilitate differentiated forest management strategies for enhancing the carbon sequestration potential of forest ecosystems in the forest-steppe zone.

Climate-readiness of fishery management procedures with application to the southeast US Atlantic

Abstract Global climate change threatens the assumption of stationarity inherent in many fisheries management decisions. This heightens the importance of developing management strategies that are robust to future uncertainty. Management strategy evaluation (MSE) is a framework in which management procedures (MPs) can be developed and tested using closed-loop simulation. We explored the performance of various model-based and empirical MPs with nonstationary future projections for three commercially and recreationally important fish stocks in the southeast US Atlantic. Using openMSE, we tested candidate MP performance across projections designed to emulate plausible future conditions, including regime shifts, nonstationarity, and observation error shifts in the survey index. Candidate MP performance was primarily measured based on its ability to maintain a healthy stock biomass. Results of this MSE demonstrate that several empirical MPs may be better able to adapt to regime shifts and nonstationary dynamics compared to traditional model-based MPs that employ full age-structured stock assessments, though empirical MPs struggle to maintain stock biomass when facing artificial index observation error shifts. Relative performance of model-based versus empirical MPs varied by stock and climate-change scenario. These findings highlight the value that adaptive MPs may hold for climate-ready fisheries management.

Tree species diversity and spatial distribution of carbon stock in forests under different management regimes in Nepal's Western Terai Arc Landscape

Reliable tree species diversity and carbon stock data are crucial for establishing a baseline and aiding monitoring and management decision-making to ensure ecosystem functions and services, including carbon management. However, such data are not available for many primary forests, especially in developing countries like Nepal. From this study, we generated primary baseline data on tree species diversity, biomass, and carbon stock for forests under different management regimes in one of the critical landscapes of western Nepal. We sampled 94 clusters of concentric circular sample plots placed systematically at the nodes of 3 km by 3 km square grids in biological corridors (managed by community forest user groups) and a national park's buffer zones (managed by buffer zone user groups) to study the tree species composition and estimate the carbon stock. The number of tree species and botanical families reported in different sites did not differ significantly. The basal area was found to be highest in Brahmadev Corridor where tree density per unit area was also highest. Our study sites showed a basal area ranging from 26.42 to 40.65 m2/ha, which is higher than previously reported from similar forests. The total biomass (302.12 to 496 tons/ha) and carbon stock (142 to 233.12 tons/ha), both being highest in Brahmadev Corridor, were within the range of comparable data and national averages. The number of stems in all sites showed the reverse J-shaped pattern, indicating a stable population and good species recruitment. The buffer zones had a large proportion of forest area with the highest carbon stock classes of 300–400 tons/ha. The basal area and diameter at breast height showed a significant positive correlation with carbon stock, indicating that the basal area is a key determinant of carbon stock. Our study provides disaggregated information on tree species diversity, the quality of forests in terms of stem density and size-class distribution, and carbon stock and its distribution in different carbon stock classes in two forest management regimes. In this sense, our study is the first of its kind in providing important insights into forest and carbon management because areas with different carbon stocks need different management prescriptions.