Removal Treatment Research Articles

Timing of defoliation affects anthocyanin and sugar decoupling in Grenache variety growing in warm seasons

Warming trends over the winegrowing regions lead to an advance of grapevine phenology, decreased yield and increased sugar content with a lower polyphenol content. We hypothesized that different leaf removal timings may counteract these effects. A two-year experiment was conducted in La Rioja (Spain) with Vitis vinifera L. cv. Grenache trained in an open-vase system. Trial consisted in a complete block design with two leaf removal treatments differing in the moment of manipulation: i) severe leaf removal treatment conducted after fruit set (ELR); and ii) severe leaf removal at veraison (LLR) compared to an untreated control (Control). Both leaf removal treatments tended to decrease sugar content with no effect on yield, these effects being highly affected by the year. Defoliation accounted for a decreased flavanol and stilbene contents in berries at harvest. An ELR increased anthocyanin and phenolic acid contents at harvest, while warming during 2022 accounted for decreased contents of all the monitored groups of flavonols. ELR was only effective for delaying ripening by means of impairing the sugar:anthocyanin decoupling during the 2021 growing season which was related to lower % of kaempferol. Altogether, results suggested that defoliation should still be applied under currently warming trends in some viticulture regions.

PERCEPTUAL DIFFERENCES OF TREE REMOVAL IN DEVELOPMENT AREAS AMONG LANDSCAPE PROFESSIONALS

Urban areas employ proactive strategies to effectively manage their urban tree population, aiming to enhance the overall coverage of tree canopies. This process involves certified landscape practitioners (ALP) and individuals without formal professional credentials (LP) who collectively contribute to decision-making processes. However, there is limited information on the perception among these LPs. Thus, this study employed a questionnaire survey to obtain empirical observations from the perceptions of landscape professionals in both groups about tree removal by comparing similarities and differences and identifying the factors influencing existing tree removal decisions in development areas. The study used simple random sampling involving 265 respondents, 102 ALPs and 163 LPs. Descriptive and exploratory factor analysis (EFA) were used to analyse the data. Results showed that the tree removal was a common decision in urban development. Both groups of respondents agreed on three factors influencing tree removal in development areas: institutional constraints, resource availability, and cost/benefit, with institutional constraints being the primary determinant of the decision-making process. Additionally, ALPs posited that the physical environment influences tree removal decision-making. On the other hand, The LPs contended that this decision was also motivated by preferences and tree characteristics. This research advances urban tree retention literature and provides pertinent information for tree retention and management planning and strategy. Future studies may consider investigating the perceptions of different landscape professional credentials related to site design and construction to strengthen the research findings.

Forest management, forest vegetation, and climate influence nesting ecology of a focal bird species in the western USA

Landscape-scale forest restoration aims to restore ecological structure and function and provide habitat for wildlife. However, forest management likely has varying impacts across wildlife life stages, with consequences for population persistence. Using 10 years of nest (n = 294) survey data for a focal bird species, white-headed woodpecker (Dryobates albolarvatus), we assessed how forest management (tree removal and prescribed burning) at two spatial scales (stand [2.25 ha] and landscape [314 ha]), forest vegetation variables at three spatial scales (nest tree, local [0.4 ha], and landscape [314 ha]), and climate influenced nest initiation date, egg production, egg survival, and nestling survival. We applied Bayesian hierarchical mixed effects models to these data to identify and compare drivers at each life stage. None of the variables we considered influenced egg production; white-headed woodpeckers laid an average of four eggs. As the extent of the landscape with tree removal increased, nests initiated later. Egg survival was higher in nests with prescribed burning at the stand scale. Nestling survival was higher in sites that had been managed with burning and tree removal at the stand scale, but the relationship with burning switched to negative at the landscape scale. Only nestling survival was shaped by attributes of the nest cavity itself. Egg survival increased with increased variation in forest patch sizes at the landscape scale. Woodpeckers initiated nests earlier under warmer conditions, with previous August and September temperatures being particularly influential. Both egg and nestling survival increased with cumulative precipitation. While increased temperatures decreased egg survival, nestling survival peaked at an optimal maximum temperature (∼32 °C). This study illustrates how forest management, forest vegetation, and climate factors affecting nesting ecology vary throughout the nesting season. Additionally, effects that switch directions (positive versus negative) across spatial scales indicate spatially dependent ecological processes (e.g., nest suitability versus adult foraging). This study provides a model for assessing the effects of forest management on bird population persistence by considering the nesting season as stages with distinct ecological limitations linked to spatially-dependent factors.

Morphological Diversity Analysis of Some Existing and Endangered Dendrobium Orchid Species in Bangladesh

Dendrobium is a sympodial, epiphytic orchid that belongs to the family of Orchidaceae. Bangladesh has a total of 188 different species under 78 genera of this tribe. Among them, there are 27 species of Dendrobium. Considering the potential value, the 16 species of Dendrobium are especially highlighted for herbal, horticultural, and ornamental purposes. They are also valuable for flowering as pot plants or hanging baskets. Dendrobium orchids are highly important in economically, socially, culturally, and as medicinal orchids. The basic needs of humans, the morphological characteristics of these orchids, such as the shape of pseudobulb, leaf, variation of inflorescence, floral characteristics, and their biodiversity evaluation in Bangladesh, are very important, and have been taken up for the present study. Besides these, ruthless collection by people who are thirsty for beauty has made the species endangered. On the other hand, the species has lost its habitat due to the removal of large trees. So, this research program has been conducted to save these valuable species from extinction. In addition, by studying their morphology, scientists and researchers gain insights into the evolutionary adaptations, reproductive strategies, and ecological interactions of orchids. For the present study exist and endangered Dendrobium about 2-3 years old and flower bearing matured plants were studied for development of morphological characterization of these orchids were flourished. J. Bio-Sci. 30(2): 47-57, 2022

Alternative Tissue Sampling for Improved Detection of Candidatus Liberibacter asiaticus.

Early detection and prompt response are key factors in the eradication of 'huanglongbing' (HLB) in California. Currently, qPCR testing of leaf tissue guides the removal of infected trees. However, because of the uneven distribution of 'Candidatus Liberibacter asiaticus' (CLas) in an infected tree and asymptomatic infection, selecting the best leaves to sample, from a mature tree with more than 200,000 estimated leaves, is a major hurdle for timely detection. The goal of this study was to address this issue by testing alternative tissues that might improve the CLas detection rate. Using two years of field data, old and young leaves, peduncle bark of fruit, and feeder roots were evaluated for the presence of CLas. Quadrant-peduncle (Q-P) tissue sampling consistently resulted in better CLas detection than any other tissue type. Q-P samples had a 30% higher qPCR positivity rate than quadrant-leaf (Q-L) samples. No significant seasonal patterns were observed. Roots and single peduncles had similar detection rates; both were higher than single leaves or Q-L samples. If symptoms were used to guide sampling, 30% of infected trees would have been missed. Taken together, these results suggest that Q-P tissue sampling is the optimal choice for improved CLas detection under California growing conditions.

Cobalt ferrite nanoparticle for the elimination of CD133+CD44+ and CD44+CD24−, in breast and skin cancer stem cells, using non-ionizing treatments

BackgroundCancer stem cells (CSCs) are the most challenging issue in cancer treatment, because of their high resistance mechanisms, that can cause tumor recurrence after common cancer treatments such as drug and radiation based therapies, and the insufficient efficiency of common treatments in CSCs removal and the recurrence of tumors after these treatments, it is essential to consider other methods, including non-ionizing treatments likes light-based treatments and magnetic hyperthermia (MHT). Method and materialAfter synthesis, characterization and investigation, the toxicity of novel on A375 and MAD-MB-231 cell lines, magnetic hyperthermia and light-based treatments were applied. MTT assay and flow cytometry was employed to determine cell survival. the influence of combination therapy on CD44 + CD24−and CD133 + CD44+ cell population, Comparison and evaluation of combination treatments was done respectively using Combination Indices (CIs). ResultThe final nanoparticle has a high efficiency in producing hydroxyl radicals and generating heat in MHT. According to CIs, we can conclude that combined using of light-based treatment and MHT in the presence of final synthesized nanoparticle have synergistic effect and a high ability to reduce the population of stem cells in both cell lines compared to single treatments. ConclusionIn this study a novel multi-functional nanoplatform acted well in dual and triple combined treatments, and showed a good performance in the eradication of CSCs, in A375 and MAD-MB-231 cell lines.

What’s at Play: Humpback Whale Interaction with Seaweed Is a Global Phenomenon

The use of objects by cetaceans is well known, and their ability to interact with their environment in complex behaviours has been demonstrated previously. However, baleen whales, including humpback whales (Megaptera novaeangliae), are less often observed to perform object use, but this behaviour might be more common than previously thought. Only a few isolated observations of interactions with seaweed have been reported in the scientific literature to date. The recovery of humpback whale populations, as well as the rise of technology such as unmanned aerial vehicles (UAVs) and the use of social media, allow for a new assessment of this object interaction. Here, we describe in detail three instances of “kelping” on the east coast of Australia derived from aerial observations. A summary of over 100 separate and unrelated events drawn from social media, documented by photographs and videos, suggests that this form of interaction with seaweed is observed across different populations. The form of interaction with seaweed is similar between regions, predominantly displayed between the rostrum and dorsal fin. This behaviour may be playful but could also serve additional benefits in the context of learning and socializing, as well as ectoparasite removal and skin treatment by utilizing brown algae’s antibacterial properties. Establishing this type of behaviour as distributed across different populations is important to better understand the species’ habitat preferences.

Using zeolite filters to reduce activated carbon use in micropollutant removal from wastewater

Micropollutants (MPs) are a wide group of human-made chemicals, such as pharmaceuticals and/or industrial compounds, with a negative impact on ecosystems. As they are discharged through water lines, they are a common presence in wastewater treatment plants (WWTPs). Among the known MPs removal treatments, adsorption-based processes are mostly used given their high MP removal capacity, although their production costs and environmental impact can be high. This is the case of powdered activated carbon (PAC), that remains nevertheless often the best option. Therefore, the optimization of PAC adsorption through the combination with natural zeolites is an interesting perspective. In this study, a combined approach made of zeolite-based filter and PAC to reduce water concentrations of eleven micropollutants is reported. The addition of a zeolite-based removal step increased the overall average removal by 14 % compared to 55 % obtained by the sole PAC adsorption. The combined zeolite-PAC process, by having higher removal efficiency allows a reduction in the use of PAC with interesting potential savings in costs and CO2 emissions. Also, a zeolite step before conventional PAC can ease the organic matter loading on the carbon, allowing for an improved recirculation in the biology tank, and can make the use of renewable sources-based PAC more appealing.

ERCP using balloon-assisted endoscopes versus EUS-guided treatment for common bile duct stones in Roux-en-Y gastrectomy

To compare endoscopic retrograde cholangiopancreatography using balloon-assisted endoscope (BE-ERCP) with endoscopic ultrasonography-guided antegrade treatment (EUS-AG) for removal of common bile duct (CBD) stones in patients with Roux-en-Y (R-Y) gastrectomy. Consecutive patients with R-Y gastrectomy undergoing BE-ERCP or EUS-AG for CBD stones in 16 centers were retrospectively analyzed. BE-ERCP and EUS-AG were performed in 588 and 59 patients, respectively. Baseline characteristics were similar, except for CBD diameter and angle. Technical success rate was 83.7% vs. 83.1% (P = 0.956), complete stone removal rate was 78.1% vs. 67.8% (P = 0.102), and early adverse event rate was 10.2% vs. 18.6% (P = 0.076) in BE-ERCP and EUS-AG. The mean number of endoscopic sessions was smaller in BE-ERCP (1.5±0.8 vs. 1.9±1.0 sessions, P = 0.01), whereas the median total treatment time was longer (90 vs. 61.5 minutes, P = 0.001). Among patients with biliary access, complete stone removal rate was significantly higher in BE-ERCP (93.3% vs. 81.6%, P = 0.009). CBD diameter ≥15-mm (Odds ratio [OR], 0.41) and an angle of CBD <90-degree (OR, 0.39) were negative predictive factors in BE-ERCP, and a stone size ≥10-mm (OR, 0.07) and an angle of CBD <90-degree (OR, 0.07) in EUS-AG. The 1-year recurrence rate was 8.3% in both groups. Effectiveness and safety of BE-ERCP and EUS-AG were comparable in CBD stone removal for patients after R-Y gastrectomy, but complete stone removal after technical success was superior in BE-ERCP.

Cleaner Fish Do Not Impact the Pigmentation of Salmon Lice (Lepeophtheirus salmonis) in Commercial Aquaculture Cages

Salmon lice are one of the biggest challenges to sustainable salmonid aquaculture. The species display high evolutionary potential, which is evident by its development of resistance to numerous chemical compounds used for delousing. In response to this, salmon farms now use non-chemical delousing methods to minimize the damage done by salmon lice, including heavy reliance on cleaner fish. Anecdotal reports from farmers and fish health personnel in areas where cleaner fish are used have suggested that salmon lice are becoming less pigmented, potentially making them harder for cleaner fish to visually detect. This experiment investigated changes in the pigmentation of salmon lice in relation to the use of cleaner fish, louse stage and sex, temperature, preferred salmon swimming depth, daylength, and salinity. Salmon lice were sampled from snorkel cages on a commercial salmon farm where three cages were stocked with farmed lumpfish and ballan wrasse, and three cages were without cleaner fish. Water temperature, salinity, and depth were recorded using a conductivity, temperature, and depth recorder. Pigmentation was measured via photographic analysis of individual lice. Although louse pigmentation varied considerably throughout the experiment, using cleaner fish throughout a single production cycle did not reduce average louse pigmentation compared to control cages. On average, male lice were significantly darker pigmented than females, but otherwise there were no patterns in louse pigmentation in relation to life stage, salinity, temperature, or daylength. Salmon lice exhibit a high degree of evolvability and have become resistant to every chemical removal treatment developed thus far. The present data suggest that, with the densities and species of cleaner fish commonly used in commercial salmon production, there is not strong directional selection on louse pigmentation. Lice, at least with regard to visual appearance, are not likely to adapt in a way which reduces cleaner fish efficacy anytime soon.

Comparative study of per- and polyfluoroalkyl substances (PFAS) removal from landfill leachate

Landfill leachate is one of the major point sources of per- and polyfluoroalkyl substances (PFAS) pollution. In this study, powdered activated carbon (PAC), granular activated carbon (GAC), anion exchange resin (AIX), nanofiltration (NF), ozonation, and foam fractionation were tested for treatment of the same leachate. These methods were compared in terms of PFAS removal efficiencies and treatment cost. More than 75% removal of long-chain PFAS (6–9 CF2) could be achieved with all the studied methods, though with high resource consumption. It was demonstrated that PFAS breakthrough was up to 27 times faster when the leachate was treated with GAC and AIX compared to groundwater treatment. Nanofiltration was the only method which could be practically applied for removal of PFAS with the shortest fluorinated carbon chain (3–4 CF2). Foam fractionation and AIX offered the most economical treatment, with an estimated cost of < 1 €/m3 for PFOS and PFOA reduction to ≥ 90%. The cost of treatment was shown to increase exponentially if the goal of > 60% ΣPFAS11 removal was applied. It was also discussed that composite parameters that include expected toxicity of different PFAS, such as ΣPFOAeq, should be used to obtain a cost-efficient reduction of PFAS-induced water toxicity.

Removal of Unwanted Hair: Efficacy and Safety of 755-nm Alexandrite Laser Equipped with a 30 mm Spot Handpiece.

Background: Alexandrite 755 nm laser has been currently recognized one of the gold standards for the permanent hair removal business because of its sufficient tissue penetration and higher affinity for melanin compared with Nd:YAG, making the treatment more incisive and effective. Objective: In this study, we evaluated an Alexandrite 755 nm laser with a 30-mm spot for a new and fast hair removal treatment. Methods: Patients of both genders, with skin Fitzpatrick's types, ranging from II to III, were asked to avoid any epilation techniques 4 weeks before the laser hair removal session. Participants underwent a minimum of three to a maximum of eight sessions of treatment, every 6 weeks. Six months after the last treatment, the final evaluation was completed. The treated body areas included arms, legs, axillae, and trunk. The subjects used a numeric scale with a range of 0 to 10 (0: no pain, 10: unbearable), to indicate the associated pain level experienced. By comparing the percentage of terminal hairs before and after laser treatment, hair reduction was determined. Results: The patients reported only slight post-treatment erythema that disappeared after a few hours and only two patients showed persistent erythema lasting a few weeks. The pain was found to be 4.9 ± 0.9 after single pass emission. Conclusions: The 755 nm laser with the new handpiece has proven to be an ideal wavelength for hair removal, allowing efficient, safe, and faster treatments to be performed for the patient.

Factors associated with dental implant loss/complications in the Veterans Health Administration, 2015-2019.

Twelve percent of the U.S. population has a dental implant. Although rare, implant loss/complications can impact quality of life. This study evaluated indicators for implant loss/complications. Veterans with dental implants placed between 2015 and 2019 were included. Implant loss/complications were defined as implant removal or peri-implant defect treatment within 90 days. Binomial logistic regression identified factors associated with implant loss/complications. From 2015 to 2019, 48,811 dental implants were placed in 38,246 Veterans. Implant loss/complications was identified for 202 (0.4%) implants. In adjusted analyses, Veterans aged 50-64 years (OR = 1.92 (95% confidence interval (CI): 1.06, 3.46)) and ≥65 (OR = 2.01 (95% CI: 1.14, 3.53)) were more likely to have implant loss/complications. History of oral infection, tooth location, and number of implants placed all significantly increased the odds of loss/complications. Dental implant loss/complications are rare outcomes. Older age, location of implant, and the number of implants placed during a visit were significant predictors of loss/complication.

PopEquus: A predictive modeling tool to support management decisions for free‐roaming horse populations

AbstractFeral horse (Equus caballus) population management is a challenging problem around the world because populations often exhibit density‐independent growth, can exert negative ecological effects on ecosystems, and require great cost to be managed. However, strong value‐based connections between people and horses cause contention around management decisions. To help make informed decisions, natural resource managers might benefit from more detailed understanding of how horse management alternatives, including combinations of removals and fertility control methods, could achieve objectives of sustainable, multiple‐use ecosystems while minimizing overall horse handling and fiscal costs. Here, we describe a modeling tool that simulates horse management alternatives and estimates trade‐offs in predicted metrics related to population size, animal handling, and direct costs of management. The model considers six management actions for populations (removals for adoption or long‐term holding; fertility control treatment with three vaccines, intrauterine devices, and mare sterilization), used alone or in combination. We simulated 19 alternative management scenarios at 2‐, 3‐, and 4‐year management return intervals and identified efficiency frontiers among alternatives for trade‐offs between predicted population size and six management metrics. Our analysis identified multiple alternatives that could maintain populations within target population size ranges, but some alternatives (e.g., removal and mare sterilization, removal and GonaCon treatment) performed better at minimizing overall animal handling requirements and management costs. Cost savings increased under alternatives with more effective, longer lasting fertility control techniques over longer management intervals compared with alternatives with less‐effective, shorter lasting fertility control techniques. We built a user‐friendly website application, PopEquus, that decision makers and interested individuals can use to simulate management alternatives and evaluate trade‐offs among management and cost metrics. Our results and website application provide quantitative trade‐off tools for horse population management decisions and can help support value‐based management decisions for wild or feral horse populations and ecosystems at local and regional scales around the world.

Utilization of Low Cost Biofertilizers for Adsorptive Removal of Congo Red Dye.

Presence of colors, organic surface finishing agents and surfactants in textile industry effluent makes it highly detrimental for surrounding environment. Hence the effluent from textile industry needs treatment for removal of these colors, organic and inorganic components before its disposal. Hence applicability of low cost and environmental friendly biosorbents, Azospirillium biofertilizer and Rhizobium biofertilizer were investigated for removal of Congo red dye. Batch experimentation was carried out to check operating parameters like, temperature, dose of adsorbent, pH, agitation speed, contact time and initial concentration. The biosorption capacity for Congo red dye was 67.114 and 101.01mg/g, for Azospirillium biofertilizer and Rhizobium biofertilizer, respectively at optimized parameters. RL factor was 0.558 and 0.568 for Azospirillium biofertilizer and Rhizobium biofertilizer. The data showed combination of interaction-based separation through better fitting of Langmuir isotherm compared to Freundlich. Its separation is well described by Pseudo-second order and intraparticle diffusion model. Adsorption was favorable at lower temperature suggesting exothermic and spontaneous nature. Reusability for Azospirillium biofertilizer and Rhizobium biofertilizer was checked for 25mg/land. While the biological nature of Azospirillium and Rhizobium biofertilizer makes removal of Congo red dye environmentally benign.

Interactive effect of tillage, residue, nitrogen, and irrigation management on yield, radiation productivity and water productivity of winter wheat in semi-arid climate

Water, nutrients, and energy are the three main inputs in agricultural production and recently there has been a drop in the factor productivity of these inputs because of their improper management and deterioration of soil health. To maximize agricultural productivity while lowering strain on natural resources, the best synergistic combinations of tillage, residue, nitrogen, and water management should be identified for improving resource use efficiency of wheat. Hence, an attempt has been made to evaluate the impact of contrasting tillage, crop residue mulch, nitrogen, and irrigation interaction on yield, radiation productivity (RP), and water productivity (WP) of wheat in a split-factorial design. Results showed that wheat yield was higher under no-tillage (4.8%) than that of conventional tillage. Crop residue mulch (CRM) and higher nitrogen application enhanced RP, WP, and yield of wheat; although RP increased with increase in nitrogen application up to 100% recommended dose of nitrogen (RDN). CRM significantly reduced the seasonal evapotranspiration (6.0‒7.2%) as compared to residue removal treatment. Deficit irrigation enhanced the WP while it lowered the crop yield significantly. Therefore, wheat can be grown under no-tillage, CRM, 100% RDN with deficit irrigation to obtain higher WP but with full irrigation to obtain higher yield, and RP in the semiarid climate of India.

Electrically Controlled Adsorptive Membranes with Tunable Affinity for Selective Chromium (VI) Separation from Water.

Ionic contaminants such as Cr(VI) pose a challenge for water purification using membrane-based processes. However, existing membranes have low permeability and selectivity for Cr(VI). Therefore, in this study, we prepared an electrically controlled adsorptive membrane (ECAM-L) by coating a loose Cl--doped polypyrrole layer on a carbon nanotube substrate, and we evaluated the performance of ECAM-L for Cr(VI) separation from water. We also used electrochemical quartz crystal microbalance measurements and molecular dynamics and density functional theory calculations to investigate the separation mechanisms. The adsorption and desorption of Cr(VI) could be modulated by varying the electrostatic interactions between ECAM-L and Cr(VI) via potential control, enabling the cyclic use of the ECAM-L without additional additives. Consequently, the oxidized ECAM-L showed high Cr(VI) removal performance (<50 μg/L) and treatment capacity (>3500 L/m2) at a high water flux (283 L/m2/h), as well as reusability after the application of a potential. Our study demonstrates an efficient membrane design for water decontamination that can selectively separate Cr(VI) through a short electric stimulus.

Nutrient uptake in tropical rivers receiving wastewater treatment plant discharge: High mass removal but low nutrient uptake efficiencies

Wastewater treatment plants (WWTPs) have eliminated many problems related to sewage inputs to aquatic systems. However, the treated effluents still affect river and stream ecosystems. Yet, very limited information is available about the fate of treated effluents in tropical receiving water bodies. Here, we examined the longitudinal changes in ammonium (NH4-N), nitrate (NO3-N), and soluble reactive phosphorus (SRP) concentrations in reaches downstream from chronic WWTP inputs in three receiving rivers in São Paulo state (Southeastern Brazil). The studied WWTPs were not designed or operated to have specific tertiary treatment for nutrient removal at the time of the study. We conducted a total of five sampling campaigns between 2019 and 2021. We applied the nutrient spiraling approach to these high-magnitude nutrient additions to examine net nutrient uptake. Changes in nutrient loads along the reaches were also examined. Overall, nutrient concentrations and loads were considerably increased by WWTP discharges. Net uptake lengths (SW-net) for NO3-N, NH4-N, and SRP ranged from 1.2 to 13.6, 1.5–infinity (uptake coefficient < 0), and 1.2–7.5 km, respectively. Net uptake velocities (Vf-net) varied between 0.7–2.5, −0.4 to 4.1, and 0.2–10.2 mm/min, respectively. Areal net uptake rates (Unet) ranged from 0.78 to 10.7, −20.08–45.8, and 0.18–4.4 g/m2/min for NO3-N, NH4-N, and SRP, respectively. High export (long SW-net) and limited net uptake along the reaches (low Vf-net) indicated that nutrients were transported downstream for long distances without efficient removal (nutrient availability higher than demand) despite the high mass removal (high Unet). These results suggest that the export of nutrients is substantial, potentially creating water quality impairments to downstream ecosystems. Our study highlighted that WWTPs with limited nutrient removal have considerable effects on water chemistry, nutrient cycling and loading in tropical receiving freshwaters.

Slow soil enzyme recovery following invasive tree removal through gradual changes in bacterial and fungal communities

Abstract Biological invasions of plants have profound effects on ecosystem functioning by directly and indirectly altering soil microbiota, especially when invasive plants co‐invade with their associated microbiomes. Ecosystem functions may recover slowly following invader removal, with implications for restoration. We investigated the recovery of soil ecosystem function (measured as soil enzymes) following the removal, at different densities and times, of invasive Pinus spp. in New Zealand, and how different enzymatic activities responded to pine legacies. Enzymatic activities were driven by pine legacies via both abiotic (soil nutrients) and biotic (fungi and bacteria) soil properties, with different enzymes showing distinct patterns. The activity of the enzymes cellobiohydrolase (cellulose degrading), β‐glucosidase (cellulose degrading), N‐acetyl‐glucosaminidase (chitin degrading), laccase (lignin oxidising) and acid phosphatase (organic phosphate hydrolysing) were influenced by time since pine removal and by pine density at removal via effects on biotic communities. In comparison, Mn‐peroxidase (lignin oxidising) was positively correlated with density of pines at removal and was negatively correlated with time since removal and was only influenced by fungal communities. Synthesis. The recovery of soil enzymatic function following invasive species removal is slow and dependent on pine legacies through the gradual changes in fungal and bacterial communities. The cascading effects of these changes suggest potential implications for the success of future plant establishment and restoration of co‐invaded ecosystems.

Roots exert greater influence on soil respiration than aboveground litter in a subalpine Cambisol

Aboveground plant litter and roots are primary sources of soil organic carbon (SOC), profoundly affecting soil respiration and SOC dynamics. With global change, the quantities of aboveground plant litter and root inputs into soil are changing in the subalpine region; however, the impacts of these changes on soil respiration and the quantity and quality of SOC remain unclear. Here, a three-year detritus input and removal treatment (DIRT) experiment that included six treatments (namely, control, CK; double litter, DL; litter removal, NL; root exclusion, NR; root exclusion plus double litter, NRDL; and root exclusion plus litter removal, NRNL) was conducted in a subalpine Cambisol on the eastern edge of the Tibetan Plateau to assess the different effects of aboveground litter and roots on soil respiration and the quantity and quality of SOC dynamics. Among the treatments, the mean soil respiration in NL, NR and NRNL treatments significantly decreased by 21.7%, 31.9% and 40.5%, respectively, compared to the CK treatment. When with intact roots, double litter (DL) had a positive impact on soil respiration, resulting in a 13.2% increase in soil respiration compared to the CK treatment. In contrast, when with root exclusion (in the absence of roots), combined root exclusion and litter addition (NRDL) hardly influence soil respiration compared with the NR treatment, resulting in a 30.5% decrease in soil respiration. The soil respiration, labile SOC content and the abundance of soil microbes exhibited similar patterns among treatments. Roots excluded (NR, NRDL, NRNL) exerted a stronger effects on soil respiration, temperature sensitivity of soil respiration (Q10), labile SOC content and the recalcitrance index of carbon (RIC) than aboveground plant litter manipulation (CK, DL, NL). Correlation analysis and redundancy analysis revealed that soil respiration and its Q10 were regulated by the quantity and quality of SOC substrates and the abundance of soil microbes. Our results highlighted that roots exerted greater influence on the quantity and quality of SOC, the abundance of soil microbes, soil respiration and its Q10 than aboveground litter manipulation in subalpine Cambisol in response to future climate scenarios, especially the mediating effect of the presence of roots on the function of aboveground plant litter.