Operations of a pumped storage power plant attenuated radioactive Cs concentration in kokanee stocked in the upper reservoir.

A consequence of past acid rain events has been chronic acidification of Nova Scotian forests, leading to a loss of essential nutrients and subsequent decreases in forest productivity and biodiversity. Liming-supplementing forests with crushed limestone-can restore essential nutrients to acidified soils and increase the pH of soils and the carbon capture by forests through the promotion of tree growth. Liming treatments are often assessed through tree growth measurements, although little is known about how microorganisms respond to these changes in pH and nutrient availability. Understanding the impacts of liming on microbial communities will help determine whether liming is a good remediation strategy for Nova Scotia. A pilot study evaluating liming in acidified forests in Nova Scotia began in 2017. Microbiome analysis (prokaryotic 16S and fungal ITS2 rRNA gene amplicon sequencing) of three different horizons (depths; upper forest floor, lower forest floor, and upper B horizon) of soil in a softwood forest area showed significant differences between lime-treated and control soils for the prokaryotic but not fungal communities, particularly in the uppermost soil horizon. Several genera from the Alphaproteobacteria class were significantly higher in abundance in treated than control soils, whereas genera from the Acidobacteriia (previously Acidobacteriae) class were significantly lower in abundance in treated versus control soils. Soil chemistry analysis of the same three horizons showed a significant increase in base cations and pH of the uppermost soil horizon in control versus treatment sites.IMPORTANCEForests are increasingly being managed with an emphasis on understanding how forests function. Lime amendments are used to promote forest health and increase resilience to climate change. To date, only a handful of studies have analyzed the effects of liming on microbial communities in forest soils. Our study combines soil chemistry with prokaryotic and fungal communities of limed and control soils. Shifts in microbial composition that are coincident with liming may provide early indications of the effectiveness of liming and provide insight into the roles of microbes in forest health.

Litter plays a vital role in forest ecosystems, significantly contributing to nutrient cycling through litter production and decomposition. Understanding these processes is crucial for forest management and conservation, especially in the face of global environmental changes. This research is important because it provides insights into the litterfall patterns and nutrient dynamics of different tree species, which are essential for maintaining forest health and productivity. The present study aimed to determine the quantity and pattern of litterfall and nutrient return to the forest floor of Pinus roxburghii, Shorea robusta, and Bambusa tulda. We collected litterfall monthly over two years in three different plantations of P. roxburghii, S. robusta, and B. tulda, and measured the nutrient content of the litter. The mean annual litter production recorded in these plantations was greatest in B. tulda (4652.15 kg ha-1yr-1), followed by S. robusta (3731.4 kg ha-1yr-1) and P. roxburghii (2588.85 kg ha-1yr-1). The plantations included both the main species and associated understory vegetation, such as herbs and shrubs. Leaf litter from the main species accounted for the highest total litterfall in April. During this period, leaf litter accounted for approximately 24% of the total in S. robusta, 16% in P. roxburghii, and 15% in B. tulda. Minimum mean monthly litterfall was recorded in September and November for P. roxburghii and S. robusta, and in November and December for B. tulda. There was significant monthly variation in nutrient content between the species. Maximum nitrogen (N) was measured during June for P. roxburghii, December for S. robusta, and January for B. tulda, and phosphorus (P) and potassium (K) concentrations also varied significantly. Annual patterns of nutrient return followed the order N > K > P. Maximum nutrient return was observed during April in all species due to higher litter production during that month. There was greater variability in litter quality in the broadleaved forest (S. robusta) than in the coniferous forest (P. roxburghii), indicating the more dynamic functioning of broad-leaved plantations compared to coniferous ones.. This research highlights the critical role of litterfall in nutrient cycling within forest ecosystems and underscores the importance of considering species-specific litter dynamics in forest management and conservation strategies.

Brood pollination mutualisms are obligate interactions in which the specialized insect generally evolves parasitism of its pollinated flower, but whether pollen parasitism could also evolve in nursery pollination systems remains little known. Aspects of pollination, particularly floral phenology and anthesis, as well as feeding habits and life cycles of pollinators, were examined in seven species of Aspidistra (Asparagaceae), in which flowers of most species are cryptic, usually covered by forest litter. The 9-yr field study found that at least six species were pollinated by fungus gnats (Mycetophilidae, Sciaridae) or gall midges (Cecidomyiidae), and their larvae were pollen parasites of the pollinated flowers. As illustrated here, Aspidistra saxicola was exclusively pollinated by a female midge, whose adults fed on pollen and oviposited in flowers, and whose larvae developed in 3-4 d on a diet of the pollen within the corolla. The timing of the midges' life cycle matched the flowering phase of pollen provision for 4-7 d. Unlike previously reported obligate brood pollination mutualisms, in which larvae are seed predators, the sole pollinators, gall midges or fungus gnats, are completely dependent on pollen in multiple species of Aspidistra, illustrating a new fly-pollinated pollen-parasite mutualism in angiosperms.

Forests store carbon in wood, forest floor, and soil. Carbon stock and distribution between these compartments differ across forests. The Monfragüe National Park (West Spain) is home to a variety of forests resulting from contrasting land use histories. These include holm and cork oak (Quercus ilex and Q. suber) dehesas (open forests with low-intensity agro-silvo-pastoral use), and pine (Pinus pinaster) and eucalypt (Eucalyptus camaldulensis) plantations, which pursued wood production. These uses ceased decades ago. Part of the former eucalypt plantations was removed and planted with native oaks, but the restoration failed leading to a Cistus ladanifer shrubland. In these five vegetation types, we assessed carbon stock and partitioning among above- (tree and shrub canopy, and forest floor) and belowground compartments (roots and soil); we also assessed tree health, and potential for tree regeneration as indicators of carbon stock persistence. We measured tree dimensions, shrub cover and height, and collected forest floor and soil samples for organic carbon analyses. Allometric equations were used to estimate tree and shrub carbon stocks. Plantations were expected to show a less diverse undercanopy but higher carbon stocks than dehesas, whereas dehesas were expected to allocate a greater proportion of carbon belowground, and to exhibit better tree health and regeneration. Total carbon was the highest in the pine and eucalypt plantations, followed by oak dehesas and minimum in the C. ladanifer shrubland. The shrub layer contributed more to the total carbon stock in the C. ladanifer shrubland and in the eucalypt plantation (13-14%), but ≤ 2% in the pine plantation and in the dehesas. The belowground carbon fraction was greatest in the oak dehesas (c.a. 60%), followed by the pine (55%) and eucalypt (46%) plantations. C. ladanifer shrubland showed an unexpectedly high proportion of carbon in the soil, probably due to legacy effects of the former plantation. Tree health was poorest in eucalypts, followed by cork oaks, while pines and holm oaks showed a better condition. Tree regeneration was poor in all forest types, likely due to canopy competition (plantations) and herbivory (dehesas). Although pine and eucalypt plantations store more total carbon, oak dehesas offer more stable storage due to higher belowground carbon. However, regeneration failure threatens their long-term persistence. Our results show that past land use largely determines forest capacity to store and retain carbon over the long term. Enhancing forest resilience should be a central goal of management aimed at strengthening carbon sink services.

Forest fine root litter enters agricultural soils in some cases and its decomposition would change the soil’s properties. However, how this process further influences the ammonia (NH3) volatilization and nitrous oxide (N2O) emission from agricultural soil receiving fertilizer nitrogen (N) is unknown. Here, we conducted a soil pot experiment to investigate the responses of the aforementioned gaseous N losses during wheat season to fine root litters derived from Populus deltoides (RP) and Metasequoia glyptostroboides (RM) incorporations. The results showed that two forest fine root litters reduced total NH3 losses by 30.6−31.9% from 180 kg N ha−1 applied to farmland soil, and this effect was attributed to decreased soil urease activity and ammonium-N during the basal N fertilization period. Whether receiving fertilizer N or not, N2O emissions from farmland soil were significantly (p < 0.05) mitigated by 62.8–68.2% and 43.0−50.0% following the RP and RM incorporation, respectively. Lower N2O emission was ascribed to increased soil pH but decreased soil nitrate-N and bulk density. In addition, less AOA and AOB amoA but more nosZ gene abundances explained the fine root litter-induced N2O mitigation effect. Neither forest fine root litter exerted a negative effect on wheat grain yield and crop N use efficiency in N-added agriculture soil. In conclusion, forest fine root litter incorporation could help to mitigate gaseous N losses via NH3 volatilization and N2O emission from fertilizer-N-applied agricultural soils, and without crop production loss.

Abstract Background Wildland fuels are fundamental variables in modeled predictions of fire behavior and effects. In forest ecosystems, accumulated forest floor layers, including recently fallen litter and highly decomposed organic material (i.e., duff), often constitute most surface fuel—biomass and stored carbon. Associated error in estimated litter and duff biomass can thus propagate to major sources of uncertainty in predicted fire effects, including tree mortality and smoke production. Distributions of forest floor biomass are difficult to measure, and estimates of litter and duff biomass typically involve high uncertainty. In this study, we evaluated relationships between forest floor characteristics (i.e., depth, biomass, and bulk density) and how forest floor layers vary between locations against the boles of trees, inside tree crown drip lines, and outside tree crown drip lines. Our study focused on pine-dominated systems with open forest canopies including southeastern (SE) pine mesic flatwoods, SE loblolly pine plantations with sweetgum understories, and western (W) ponderosa pine and mixed conifer forests. Results Across the three forest types, litter depths were highest in SE flatwood sites and lowest in W pine sites, but W pine litter generally had higher bulk density and thus greater biomass than SE pine sites. Duff depth and biomass were greater in W sites, likely related to less frequent burning and slower rates of decomposition than SE forests. Linear regression models were constructed to predict litter and duff biomass from sampled depth and transect positions for each forest type. Even with high variance among samples, there were significant differences in litter and especially duff characteristics across transect positions. Across all forest types, litter and duff accumulations generally were significantly greater inside than outside tree crowns, particularly when bole and outside positions were compared. Conclusions Modeled relationships revealed significant trends that could inform process models of forest floor development and decomposition over time. With increased availability of stem and crown mapping based on lidar metrics, estimates of forest floor accumulations can be made through mapping of tree crown positions and predictive modeling of litter and duff biomass in relation to tree crowns.

One of the causes of global warming is the increase in carbon dioxide (CO2) levels and the reduction in forest area as a CO2 absorber in the atmosphere. One solution to reducing CO2 levels in the atmosphere is through the development or improvement of forest vegetation, both natural and community forests. Forests are a vital part of the terrestrial ecosystem, acting as global carbon sinks and playing a role in mitigating the long-term and sustainable impacts of global warming. The objective of this research is to obtain information on the carbon content stored in the biomass of community garden land. This research was conducted from November 2023 to January 2024 in Lakan Bilem Village, Nyuatan District, West Kutai Regency, East Kalimantan Province. The research activities included: literature review, field observations, research plot creation, data collection, data analysis, and reporting. The data collected consisted of tree biomass, tree surface biomass, and understory biomass. The results of the study indicate that the amount of carbon stored in community gardens in Lakan Bilem village is 116.35 tons/ha, originating from carbon stored in biomass at the young tree and tree levels (111.64 tons/ha) and carbon stored in forest floor vegetation (4.71 tons/ha).

Thrakosphaera schawalleri was recorded for the first time in Romania: in the southern part of the Romanian Plain and the north-eastern part of the Burnazului Plain. Both qualitative and quantitative sampling methods were used. Most specimens were captured by means of Winkler sieve in leaf litter in deciduous forests. An extended re-description of the species is provided. A new family, Thrakosphaeridae fam. nov., is suggested for this species based on the following set of characters concerning the stomach inferolateralia, pereiopod I, pleopod 1 of male endopodite, pleopod 2 of male exopodite and the extension of the uropodal protopodite.

The oribatid mite family Oppiidae Sellnick, 1937 is highly diverse globally, but this group is insufficiently studied in Korea. This work deals with four species of oppiids from Korea. Rhinoppia chuleuijungi sp. nov. and Goyoppia heuksandoensis sp. nov. are proposed based on adults, and supplementary descriptions of two little-known species, Graptoppia nukusia (Shtanchaeva, 1984) and G. tanaitica Karppinen and Poltavskaja, 1990 are provided, which are reported for the first time from Korea. All species are inhabitants of the litter and soil of the mixed forests, and aspects of the taxonomy, distribution, and ecology of all species are discussed.

Abstract. Ammonia (NH3) is a significant contributor to total nitrogen deposition in East Asia. However, process-based observations that specifically focus on the air–surface exchange of NH3 remain limited in this region, especially in Southeast Asia. To clarify the bi-directional exchange process of NH3 under tropical climatic conditions, we present the first observations of NH3 exchange flux over a tropical dry deciduous forest in Thailand during two periods with different canopy and meteorological conditions in the dry season using the aerodynamic gradient method. NH3 concentrations exhibited strong positive correlations with air temperature and negative correlations with wind speed during the leafy period. However, there was no clear correlation between concentrations and meteorological elements during the leafless period. Measured NH3 fluxes fell within the ranges presented in recent studies, with a weighted mean and standard deviation of 0.148 ± 0.240 µg m−2 s−1, and consistently larger during daytime. During the dry season, the tropical dry deciduous forest acted as an emission source of NH3. Across both observation periods, NH3 emissions were governed by air temperature, relative humidity, friction velocity, and solar radiation. While no clear difference in fluxes magnitude was observed between the leafy (0.140 ± 0.240 µg m−2 s−1) and the leafless (0.158 ± 0.239 µg m−2 s−1) periods, the main source of NH3 emission in the tropical dry deciduous forest probably shifted dynamically from stomata to leaf litter due to the changes in meteorological, canopy, and forest floor conditions.

Frog-biting midges (Corethrellidae) are tropical, blood-sucking micro-predators of frogs that locate their prey by eavesdropping on anuran mating calls. In the present study we used acoustic traps broadcasting the call of Savage’s Thin-toed Frog ( Leptodactylus savagei ) to elucidate frog-biting midge stratification in the rainforest as well as the directionality and spatial scale of their phonotactic approach. In an Amazonian rainforest in Ecuador, midges were attracted to acoustic traps in all forest strata, including the canopy of an emergent tree 38 m above the forest floor, with a significant effect of stratum on midge species composition. Of the eight putative species (MOTUs) of Corethrella delimited using COI barcoding (N = 158) four were also found in the highest forest stratum (28.5–38 m), with one of them showing a preference for the middle and top canopy. In both Ecuador and Costa Rica catch numbers of ground-based traps differed strongly depending on the orientation of an attached mesh tunnel (65 cm) that was used to filter approach directions. Very few midges entered traps when mesh tunnels allowed horizontal (0°) or inclined (45°) approach vectors, while the highest catch numbers were recorded when tunnels were oriented vertically (90°). Consistent results were obtained when the length of the attached tunnel was extended to 250 cm, confirming that the primary approach to a calling host follows a vertical trajectory, and demonstrating that frog-biting midges can perceive acoustic stimuli in the acoustical far field. When stimulus intensity was varied, midges showed a significant phonotactic response at sound pressure levels as low as 56 dBA at tunnel entrance (65 cm), equivalent to a male Leptodactylus savagei calling from ~30 m distance. Our results emphasize that, despite their minute size, frog-biting midges are highly sensitive to acoustic stimuli. They are also highly mobile, occupy all strata of the neotropical rainforests and preferentially home in on their prey from above.

Foraging strategy of wood mice for undamaged and moth-infested Castanea crenata nuts on forest floor

Abstract The evolutionary arms race between insects and their predators has fueled remarkable defensive adaptations, offering insights into ecological dynamics across deep time. Fossils provide critical evidence for studying the evolution of defense strategies. Here, we describe a new lineage of Clambidae from mid‐Cretaceous Kachin amber, Scutacalyptus kolibaci gen. et sp. nov. Scutacalyptus stands out within the family due to the flattened body and fully explanate body margins. The diversity of defensive morphotypes in Cretaceous Clambidae, including conglobators like Sphaerothorax , semi‐flattened forms like Acalyptomerus , and shield‐formers like Scutacalyptus , highlights their developmental plasticity and suggests ecological differentiation in response to varied predation pressures during the late Mesozoic. This morphological divergence reflects niche partitioning in the Cretaceous forest floor ecosystem, driven by a diverse predator array including spiders, ants, lizards, and birds. The coexistence of clambids with spines or explanate margins parallels adaptations in the modern, unrelated Cassidinae, where tortoise beetles use explanate margins and some leaf‐mining beetles use spines, each tailored to counter specific predation pressures. These parallel strategies reveal how different defenses likely addressed distinct ecological challenges in the mid‐Cretaceous.

Soil scarification, which involves the disruption of the top layer of soil, is a common method utilized to promote the regeneration of tree species on clear-cut and calamity areas. In the context of adapting forests to become climate-resilient mixed species forests, this method could also be used to promote tree regeneration under intact canopies, either exclusively or in combination with direct seeding. However, evidence on the impact of this method on the composition of forest floor vegetation, including bryophytes, is lacking and needs to be investigated. This is of importance because the forest floor vegetation significantly contributes to species richness in temperate forests. To address how and to what extent soil scarification affects the forest floor species composition, we conducted a space-for-time-substitution study, creating a chronosequence spanning a 13-year period, to investigate the effect of soil scarification on forest floor vegetation in Norway spruce ( Picea abies ) stands in a lower montane forest in central Germany. Our results showed that soil scarifications were quickly recolonized by bryophyte species, whereas herbaceous species cover took around a decade to reach a similar level of establishment as the undisturbed forest floor. Species composition initially shifted in favor of early successional species. In the long term, however, the species composition converged back to the undisturbed state. Tree regeneration diversity especially benefitted from scarification, making it a viable method for intact forest stands, particularly given that it does not appear to exert any adverse effect on forest floor vegetation.

Abstract Background and Aims Forest floor vegetation can both respond to and affect the water and nitrogen (N) availability in forest ecosystems. However, their role for influencing the relationship between throughfall and N fluxes has hardly been studied, leaving a knowledge gap in our mechanistic understanding of forest biogeochemical cycling. Here we investigate the impact of the structural and functional role of the herbaceous and moss layer in linking N fluxes and throughfall patterns in beech, spruce, and pine forests in Central Germany. Methods We monitored herbaceous and moss species cover and diversity, as well as throughfall and N fluxes for 93 plots capturing small-scale microclimate variability. For all co-occurring herbaceous species, we measured intraspecific trait variation for specific leaf area (SLA) and plant height (n = 685). Results Multivariate analyses reveal strong differences in the herb and moss layer composition between forest types. The results of analyses of covariance, and of piecewise structural equation models consistently show that N fluxes decreased most under pine and spruce plots where herb and moss cover was high. Species with a high SLA and plant height positively contributed to overall herb cover. Conclusion Our results suggest that plant growth, particularly moss cover, contributed to overall N retention, while acquisitive and fast-growing species with a high SLA contributed to a fast nutrient return to the system, thereby partly increasing N fluxes. We conclude that taxonomic and functional composition of the forest floor vegetation is an important mediator in the link between throughfall and N fluxes.

Moss removal facilitates decomposition and net nitrogen loss of mixed wood and litter in subtropical forests

Bagging-OPHC: a near-infrared multispectral-based approach for high-accuracy classification of forest floor leaf litter tree species

Abstract Background Frequent mild fire regimes have been associated with healthy and bushfire-safe forests, particularly under traditional Aboriginal management in Australia and the New World. In this study, we tested the hypothesis that karri ( Eucalyptus diversicolor ) forest tree canopy health (TCH) declines with time since fire (TSF) due to changes in soil chemistry that adversely impacts tree roots. We visually assessed the TCH of dominant and co-dominant trees at 66 sites in mature karri forests based on the extent and density of foliage, the extent of epicormic growth, and the extent of branch death. TSF ranged from two to 94 years. Fire regimes can influence tree health via soil chemistry conditions, so we sampled topsoil at each site. Results A model based on TSF and soil exchangeable potassium content explained 63.9% of the variation in TCH with TSF explaining 56%. K content was an indicator of variation in soils and susceptibility to decline rather than a cause of decline. There was little evidence that changes in soil chemistry with TSF contributed to tree decline and no evidence that climate change was the primary driver of canopy decline. Conclusion Karri tree canopy decline is likely caused by the physical effects of the accumulation of forest floor litter (or mulch) on tree roots and on soil microbiota via changed soil conditions such as temperature, moisture, aeration, insolation and penetrability. Other than gravel content, we did not measure soil physical factors, so this proposal requires further investigation. If the healthy functioning of tree roots is compromised by long periods of fire exclusion, then declines in tree canopy health may be exacerbated by drought events associated with climate change.

Conotrachelus Dejean 1835, is a highly diverse genus with a poorly studied taxonomy, making species differentiation difficult. Additionally, there is limited information on its geographical distribution, particularly for species that inhabit leaf litter. This study reports 46 new records of Conotrachelus lobatus Champion, 1904 and C. scoparius Champion, 1904 collected in oak forests in central Mexico. Regular bio diversity monitoring and reporting on new records are essential for creating effective conservation strategies.