生态学报最新文献

Saline soils with complex ecosystems limit biotic activities, and the reclamation of these soils can be favorable for soil health. A pot experiment was conducted in a completely randomized design with three replications to reclaim artificially induced salinity-related attributes in soil (7.0 dS m⁻¹) using various cyanobacteria strains. For this purpose, six treatments were used, control, Oscillatory-MMF-1 (Oscillatoria princeps), Leptolyngbaya-MMF-2 (Lyngbya mucicola), Leptolyngbaya-MMF-3 (Lyngbya Phormidium), Gloeobacter-MMF-4 (Gloeocapsa) and Microcoleus-MMF-5 (Cryophilus). The salinity-induced soil was treated with the appropriate treatments before the transplantation of rice seedlings to each pot. The rice crop was grown for 100 days and monitored for growth attributes. Similarly, the soil was monitored for physicochemical properties. The experimental results revealed a significant reduction in soil pH from 8.32 to 7.20, EC from 7 to 5.2 dS m⁻¹, Na⁺ from 2552 to 1146 mg kg⁻¹, soil bulk density from 1.37 to 1.31 g cm⁻³ by the cyanobacterial strain MMF-4 Gloeobacter (Gloeocapsa), showing 13.5%, 25.7%, 55% and 4.38% decrease respectively. Whereas the cyanobacterial strain (Gloeobacter) significantly enhanced the concentration level of Ca⁺⁺ (944 mg kg⁻¹), Mg⁺⁺ (358 mg kg⁻¹) and increased the porosity up to 50.69% and saturation percentage (35.50) in the induced saline soils. It can be concluded from the findings that all the strains of cyanobacteria reclaimed soil salinity by reducing soil EC, pH, SAR, and soil bulk density and increased Ca⁺⁺, Mg⁺⁺, porosity, and saturation percentage (SP) in the saline soil. However, the best performance was recorded for MMF-4 (Gloeobacter) and MMF-5 (Microcoleus) strains and recommended for further research.

Changes in land cover land use (LCLU) have long been considered to be among the many factors responsible for global environmental challenges. This study focused on assessing LCLU changes in the Greater Gaborone area of South Eastern Botswana between 1988 and 2022. The study employed remote sensing (RS) and geographic information systems (GIS) tools for analyzing LCLU changes in the study area during the study period. Landsat images of 1988 and 2002 and Sentinel-2A images of 2022 were used to detect LCLU changes. Image classification was done using a Supervised classification approach based on a Maximum Likelihood Classifier. Six LCLU types such as water body, trees dominated, cropland, shrubland, bare land, and built-up, were identified in the area. Post Classification Comparison (PCC) approach was used to detect LCLU change during the study period. Shrubland class was found to be the dominant LCLU type in the study area. A significant gain was observed in the built-up class (75.12 km²), while significant losses were observed in shrubland (24.16 km²) and trees dominated (33.32 km²) classes in the entire study period. Given the rapid increase in built-up areas, this recommends that land managers and policymakers should invest in implementing sustainable land management interventions to prevent undesirable LCLU changes.

Plants respond in different ways to different environmental factors. This work investigated anatomical characters and phytoconstituents for Hyoscyamus muticus L. and Rumex vesicarius L. collected from two different sites, i.e., Al Qalyubia and Suez governorates. Anatomy of both plant species showed variations between the two sites: for H. muticus L., changes were mainly in the number of collenchyma rows and the area of vascular tissue, while R. vesicarius L altered the number of drusy crystals in addition to the supportive tissues. GC–MS analysis revealed variations in the secondary metabolites between the studied species grown in these different sites. Correlation analysis indicate positive correlation of Ca^++, SO₄, EC, K and TDS with the phytoconstituents of Hyosocyamus from Qualubia and negative correlation with Rumex from Qualuibia,where Mg, pH, Na and HCO₃ positively affect on Hyosocyamus from Suez. We conclude that these variations most likely contribute to the response of the two species to different environmental condition in both sites.

The research was conducted to evaluate the accumulation potential of some heavy metals in autochthonous plants around Bagega mining sites and to test their remediation potential. Soil sample and 16 different plant species were collected at four mining and gold processing sites. The content of heavy metals in the soil and different parts of the plants were determined using atomic absorption spectroscopy (AAS). The soil's Pb content was 1021 ± 198.8 mg kg¹, while the Cd, Cr, and Zn contents were 14.17 ± 0.5239 mg kg¹, 9.74 ± 1.855 mg kg¹, and 185 ± 6.45 mg kg¹, respectively. Azadirachta indica, Calatropis procera, and Eucalyptus camaldulensis were selected out of the collected plants based on their high Pb hyperaccumulation levels for phytoremediation analysis. An experiment per species was designed with three replicates in a completely randomized design. The grown plants were subjected to AAS analysis, and the accumulation of the studied metals was in the order Zn < Pb < Cd < Cr, with the highest accumulation of Pb from the contaminated soil of 68 ± 5 mg kg¹ in the root of C. procera. There was a significant difference (p < 0.005) in the absorption of all tested metals between contaminated and control sites. The enrichment coefficient and bioaccumulation factor were <1. All plants accumulate >100 times the Pb, Cd, and Cr content of plants from uncontaminated environments. The three plant species could be useful for remediating heavy metals in contaminated soil.

Due to the important role of plant species diversity and its conservation, few biodiversity studies have been conducted in tropical forests. In the present study, which was carried out in the HaftShahidan protected area of Khuzestan, the characteristics of the vegetation in five forest habitats include areas one, two, four, eight years after fire and control area were investigated. To conduct this study, the linear transect method with specific distances of 200 m in a specific east-west direction was used, then 50 sample plots with distances of 100 m from each other were dismantled toward the transects. The area of the sample plots was considered based on the size of the proposed sample plot to study the temperate to tropical forest cover (20 × 20 m). Canopy measurements for wood species (trees and shrubs) were measured at a plot of 400 m². Also, this measurement was executed for herbaceous species in 3.2 m² micro-plots that were selectively dismantled in groups of 4 (clusters) at 5 points from the surface of the sample plot. The main objectives of this study were to investigate the biodiversity, floristic characteristics, and vegetation in the control forest as a model of optimal conditions and comparison with other habitats. The study of plant species diversity between the studied treatments showed that fire can increase the richness, evenness and finally the species diversity in vegetation. It should be noted that the increase in the values of the indicators reached to the maximum after two years of the fire. The results also showed that the seedling regeneration rate of Ziziphus spina-christi (L.) Willd. tree species decreased sharply after the fire and in contrast, seedling regenerations showed an increasing trend. Finally, it can be noted that the restoration of degraded tropical forest habitats is not possible only based on biodiversity conservation in the short period after the fire, and such results will be possible after a long period of time.

The microbial community plays an important role in A. cepa productivity and soil fertility. In this study, we applied chemical (A2) and endophyte-based fertilizer (B) to A. cepa; where the use of B successfully improved productivity by the number of tubers and chlorophyll content compared to control (A1) and A2. We aimed to investigate how those fertilizers manipulate the rhizosphere bacterial community in A. cepa. The 16S-metagenomic analysis was conducted to investigate the bacterial community of the samples by amplifying the V3-V4 region. The application of A2 and B potentially enhanced the abundance of rhizosphere bacteria compared to the A1, possibly due to the increase in nutrient availability. Beta-diversity analysis showed that the B fertilizer did not highly change the bacterial community of indigenous rhizosphere bacteria, whereas the A2 fertilizer did. The endophytes themselves did not also greatly affect the original rhizosphere bacteria because they may enter the plant tissue and release the metabolites inside the plant host. The NGS data showed that the genus Aquicella was the most abundant in the rhizosphere treated with B and A1. Aquicella was discovered to boost plant resilience to contaminants by enhancing plant nutrition availability and encouraging plant root growth. Interestingly, Acidobacteria and Gemmatimonadetes decreased their population in the treatments of A2 or B. Overall, the use of B has a higher impact on plant productivity and soil properties without highly changing the composition of the bacterial community in the rhizosphere. Yet our metagenomic data support the hypothesis of phylogenetical conservation of bacterial communities concerning particular ecological conditions.

The supply of shrimp ponds water sources in this research utilizes water input from the waters of the Banyuasin River Estuary, which brings in heavy metal pollutant particles due to anthropogenic pressure. The potential for accumulation of heavy metals can occur in gastropods which are bioindicators of the pond environment. In this study, we present data on gastropods abundance and community structure concerning environmental physicochemical factors and heavy metal accumulation. Sampling was carried out in November 2021 at five observation stations spread over three shrimp ponds. The collection of gastropod samples used two methods based on achievement targets. The gastropod ecology index calculated the abundance, diversity (H′) values of heavy metals analyzed, namely Pb, Hg, Cu, and Cd. Wet digestion with an acid solution of HNO₃ and HClO was performed before measuring the concentration on the Atomic Absorption Spectrophotometer (Shimadzu AA-7000). Furthermore, all data on environmental variables were analyzed by principal components analysis (PCA) to determine the leading variable group for each station. A cluster was formed based on the Bray-Curtis similarity analysis. The results of the gastropod ecology index as a bioindicator showed moderate and low diversity (H′) and evenness (J) values, while dominance (D) was high and moderate. From two species analyzed for heavy metals, Nerita violacea and Telescopium telescopium contained Pb, Hg, and Cu concentrations, but no Cd levels were detected, including in water and sediment. Accumulation of heavy metals in shrimp ponds is not only due to the mass movement of tidal water, some of which contribute, namely the location of the inlet and outlet waterways and the position of the land to the main canal source. In general, these results indicate that the environmental conditions of the pond have accumulated heavy metal pollutants, but its whereabouts cannot be ascertained all the time. These results are sufficient to describe the current situation but need further study its impact on aquaculture production.

The present study investigated aquatic insect community of River Jatinga, one of the major north bank tributaries of Barak River, North east India. The objectives of this study were to find out spatial and seasonal distribution of aquatic insects and their functional feeding groups (FFG). Aquatic insects were collected seasonally in five different stretches of the river. Parameters like taxa richness, insect density, diversity indices, FFG%, riverbed sediment texture and particles sizes were determined. Total 37 and 38 numbers of aquatic insect families belonging to eight orders were recorded in the first and second year, respectively. In both years, the upstream sites with rocky substratum showed higher taxa richness (15) in pre monsoon and density (47.33 ± 8.5) in winter season than that of downstream sites with sandy substratum. The size of particles gradually decreased from upstream sites to downstream sites. Boulders, cobbles, pebbles and granules mostly dominated the upstream sites (US1 and US2) while boulders and cobbles were totally absent in both downstream sites. Trichoptera, Hemiptera, Ephemeroptera and Diptera were the major orders and the major families were Psephenidae, Elmidae, Baetidae, Hydropsychidae, Leptophlebiidae, Gerridae and Simuliidae. The number of FFG types was higher in upstream sites than that of midstream and downstream sites in both years indicating preference for heterogenous habitat. The predators being mostly tolerant occurred across sites and seasons while sensitive groups like scrapers, shredders were found only in the upstream sites. Predators showed highest percentage (97.56) followed by piercers-herbivores, predators/scrapers (83.33). Canonical correspondence analysis revealed distinctive association between the insect community and particle sizes.