Total Density Values Research Articles

Understory diversity and forest soil properties in different forest stands in Northern Chhattisgarh, India

The present study deals with the understory structure, diversity, and soil macro and micronutrients in various forest stands of the Duldula forest in northern Chhattisgarh. Forest stands include four natural (dense, moderately dense, regenerated, and degraded forests) and one plantation (teak). Stratified random sampling methods were used to evaluate the phytosociological attributes of shrubs, climbers, and herbs in various forest stands. Soil samples were analyzed for macro and micronutrients at two different depths (0–10 cm and 10–20 cm). A total of 14 shrubs, 17 climbers, and 30 herb species representing 9, 8, and 12 families, respectively were recorded from various forest stands. The total density value of shrubs, climbers, and herbs ranged between 600 and 1760 individuals ha−1, 320–5240 individuals ha−1, and 356,000–684,000 individuals ha−1, respectively for different forest stands. Shannon index values for shrub, climber, and herb ranged between 0.78–2.88, 1.68–2.45, and 2.57–3.59, respectively. The soil of the study area was found to be acidic in nature with moderate levels of organic carbon (%), macro, and micronutrient status. Considering the total density value of various forests stands highest number of shrubs, climbers, and herbs were recorded in degraded forests which indicates the process of degradation facilitates the growth of understory vegetation in comparison to tree species. In most cases, the soil attributes were higher in dense forests. This, therefore, indicates that sustainable management of the soil is essential for the restoration of degraded forests to a natural condition.

Strategi Pengembangan Ekowisata Mangrove Kecamatan Pariaman Utara Provinsi Sumatera Barat

This study aims to analyze the composition of mangroves, the structure of the mangrove community, and analyze the suitability of the mangrove ecotourism area. As well as analyzing the strategy of developing ecotourism areas in the Apar Pariaman Mangrove Park. The method used in this study is a survey method with a qualitative and quantitative descriptive approach. The results showed that the Apar Mangrove Park area had a mangrove composition consisting of 5 true mangrove species, namely Rhizophora mucronata, Rhizophora apiculata, Sonneratia caseolaris, Thespesia Populnea, Acanthus illicifolius, and Nypa fruticans and 2 associated species, namely Dolichandrone spathaceatigillarium, and Oncosperma. The total density at station I is 2,400.44 ind/ha, station II is 2,611.11 ind/ha and station III the total density value is 2,811.11 ind/ha. The results of the analysis of the suitability of the mangrove ecotourism area in the Apar Mangrove Park area. The category (S1) 86.84% is very suitable. Through a SWOT analysis approach. There are two priority strategies in the development, namely (1) Maximizing strategic locations and providing good service. (2) Carry out more promotions by utilizing strategic locations through social media.

Water physicochemical characterization and phytoplankton diversity of arid region in Meggarine Lake, Ouargla, Algeria

Abstract. Manamani R, Bensouilah M. 2023. Water physicochemical characterization and phytoplankton diversity of arid region in Meggarine Lake, Ouargla, Algeria. Biodiversitas 24: 1569-1579. The present study aims to examine the physicochemical parameters, e.g., temperature, dissolved oxygen, pH, conductivity, salinity, nitrites, nitrates, orthophosphates, suspended matter, and chlorophyll (a) content) of Meggarine Lake, located in the Saharian region (Ouargla). Also, to establish the relation with phytoplankton's seasonal dynamics and diversification. From November through May over four years (2016-2019), a spatial and spatiotemporal investigation of phytoplankton composition was conducted. The algae and water samples were collected, preserved, and analyzed from four different sites using standard methods. Canonical Correlation Analysis (CCA) was recorded to explain the correlation between phytoplankton and physicochemical parameters. The results revealed a link between these planktonic populations and their physicochemical properties. Observing the morphoanatomical characters of the phytoplankton genera collected in Meggarine Lake allowed us to identify 29 genera. Diatoms (15 genera), dinoflagellates (03 genera), and cyanobacteria (11 genera) were separated into three groups. The distribution of phytoplankton showed a very high algal density in 2018, with a total of 9,995 cells/L, followed by 2019 and 2017, where the total densities were 5,332 and 5,118 cells/L, respectively. A low total density value was recorded (3,157.067 cells/L) in 2016. The highest value of phytoplankton was noted during the spring season, with 19,778 cells/L. Statistical analyses showed different correlations between the physicochemical parameters and the spatiotemporal variation of algae.

Diversity of bloom forming harmful algal species in the central Bonny Estuary, Niger delta, Nigeria

This study was carried out from December 2018 to November 2019 to examine the distribution and abundance of harmful algal species (HAS) in the central Bonny estuary. Seven sampling stations were established with ArcGIS tool. Microalgae species were sampled with 20 mm mesh plankton net. Nutrients were analyzed in the laboratory using the APHA 4500 Method, while physicochemical characteristics were determined in situ. Results revealed that environmental gradients were adequate to support life in that part of the estuary except for phosphate (2.90 ± 0.22-9.48 ± 1.06 mg l-1). A total of 31 HASs categorized into 17 genera and three classes were determined: Bacillariophyceae (29 species), Chlorophyceae and Cyanophyceae (one species each). Navicula amphibola had the highest density (4.713 103 cells l-1) while Pinnularia divergens recorded the lowest density (0.00049 103 cells l-1). Total density values decreased across seasons with 9.157 103 cells l-1 in dry season and 8.907 103 cells l-1 in wet season. Checklist of species across stations showed that five species were distributed across the seven stations, while two were found only in Station 2 and 7. Diversity indices revealed Shannon’s index ranged between 3.17 and 3.25 and species evenness ranged between 0.78 and 0.88, while Margalef range value (3.09-3.31) was considered moderately stable. Therefore, there is a need for proper management practices which could help to reduce the level of nutrient discharge into the central Bonny estuary.

A novel approach to radiographic detection of growth development period with hand-wrist radiographs: Apreliminary study with ImageJ imaging software.

The purpose of this study is to determine whether or not the ImageJ program can be used to automatically determine the growth period of the hand and wrist which have different growth-development periods according to the density values in the phalanges in radiographs. Our study included hands-wrist radiographs of 270 individuals aged 8-17 years. The study's participants were classified into 7 groups according to their skeletal maturation stage (PP2=, MP3=, MP3cap, DP3u, PP3u, MP3u, and Ru) which included pre-peak, peak, and post-peak periods. The total density values (TDV) and pure density values (PDV) in the distal, medial, and proximal phalanges were calculated using each radiograph in the ImageJ program. Analysis of variance (ANOVA) was used to evaluate the density values and chronological age, and pairwise comparisons were made using the post-hoc LSD test. The total density value was graphically zigzagged in the mesial, distal, and proximal phalanges. However, the pure density value increased continuously until the post-peak period and decreased after the DP3u period until the Ru period. While no significant difference in total density values was observed between the growth periods for all three phalanges, a significant difference in pure density values was observed. It has been demonstrated in the ImageJ program that the peak growth period can be distinguished using the pure density values obtained from all phalanges of the third finger and that this method can be used as an alternative to the growth period detection through artificial intelligence.

A taxonomical and environmental study of the genus Brachionus (Rotifera: Monogononta) (Pallas, 1776) in Al-Hammer marsh, south of Iraq

Samples of Rotifera genus Brachionus were collected from Al-Barka and Al-Nagara region in Al- Hammar Marsh, South of Iraq. Remarks on the taxonomy were notes on 6 species of the genus and a monthly density of each species were recorded during the study period from Feb-2006 to Jan-2007.The highest value of total density was 2.78 ind /l recorded in May -2006, whereas the lowest value was 0.01 ind /l and reported in March-2006.

Each-Phase Metering with Gas-Liquid Stratified Flow Based on the Multi-Frequency Coriolis Principle

Gas-liquid two-phase flows generally have the characteristics of complex and variable flow patterns and flow rate uncertainty of each phase. The entrainment of gas increases errors of the existing non-separated multiphase metering. A novel metering method based on the multi-frequency Coriolis principle is proposed to solve the above problems. Compared to the conventional Coriolis mass flowmeter, the third-order mode of the measuring tube is used to improve the accuracy of the measurement. The influences of bubble effect and resonance effect on vibration responses in different vibrational modes were studied to determine the deviations of the apparent values of total density and mass flowrate by simulation. Simulation results with a single-frequency Coriolis flowmeter show that the maximum relative deviations of total density and total mass flowrate are −37.3% and −9.3%, respectively. Driven by different frequencies, the same two phase fluid in the measuring tube can have different responses of the primary mode and the higher vibrational modes. The vibrational responses characteristics corresponding to the first-order and third-order modes of measuring tube were selected and analyzed. Combined with advantages of high precision and multi-parameter measurement of traditional single-frequency Coriolis flowmeters, a multi-frequency correction model suitable for stratified flow was proposed. The results show that the corrected total density and mass flow deviations of gas-containing fluid are within ±4% and ±3%, respectively, which are significantly reduced. Corrected flowrate deviations of the gas-phase and liquid-phase are ±9.1% and ±7.2%, correspondingly, which also meet the metering requirements of the wellhead.

Kondisi dan pola pemanfaatan siput gonggong di Perairan Pulau Penyengat Kecamatan Tanjungpinang Kota, Kepulauan Riau, Indonesia

This study aims to determine the conditions and patterns of utilization of snails in the Penyengat island waters, Riau Island, Indonesia. The method used was purposive sampling of 5 stations with 70 x 2 m quadratic transect for the density of the Gonggong Snail. The results found two types of snail bark species namely Laevistrombus turturella and Strombus urceus with a total density value of 0.114individual per m². The use of snail bark patterns in Penyengat Island waters, namely the size of the catch is medium to large, manual capture techniques (collected by hand), the catching area in the waters of the island is 100-200 m from the beach, the most catches found >100 individuals, season and time of catching snail barks at stinging island waters are not based on season, utilization and distribution of utilization. The snail bark resource is used for consumption and sold to collectors.

Theoretical and experimental study of FeSi on magnetic and phase properties

In the present work, the structural, magnetic, and theoretical analysis of the Fe–Si alloy prepared by melting and heat-treated was performed. The ordered FeSi simple cubic (sc) phase was obtained by melting and heat treatment processes as determined by X-ray diffraction. The presence of the superstructure peak in the (312) crystalline direction confirms the high structural order reached. Using Mossbauer spectrometry (MS), a paramagnetic behavior with quadrupole splitting of SQ = 0.53 ± 0.02 mm/s was obtained. Although MS indicates paramagnetic behavior, vibrating sample magnetometry (VSM) showed ferromagnetic behavior with a coercive field of 25 Oe, associated with a small amount of Fe3Si segregations detected by scanning electron microscopy/energy dispersive spectrometry (SEM/EDS). Using density functional theory (DFT), the crystalline structures for the simple cubic (sc) Fe50Si50, face-centered cubic (fcc) Fe3Si, and body-centered cubic (bcc) Fe3Si crystalline structures were simulated. Electron total density values were calculated to perform energetic comparisons with magnetic behavior. The electronic structures and magnetic properties of the Fe–Si alloys in different stoichiometric configurations were calculated by CASTEP, which employed first principles DFT. The density of states (DOS) and band structures were calculated together with magnetic properties. The results showed that the high value of the polarization spin for the fcc and bcc structures is due to the contribution of the high amount of Fe atoms above the Si atoms, which is reflected in an increase in the magnetic moment and that their presence could explain the ferromagnetic behavior observed by VSM.

The potential stocks and carbon uptake by seagrass meadows at Pari Island, Kepulauan Seribu, Indonesia

The development of human civilization during the last century has increased carbon dioxide content in nature that will contribute to global climate change. However, ocean water will reduce this increase by absorbing CO2. The increasing CO2 content in the ocean could decrease pH and carbonate ion, which will have negative impacts on the life of marine organisms, food production and human life. Seagrass meadows through photosynthetic processes could absorb CO2 and store carbon in large amounts for an extended period. This process could be the strategic way of resolving global climate change. The purpose of this research was to identify the species of seagrass, quantify the density and coverage of seagrass, and calculate biomass and carbon stock in seagrass meadows at Pari Island, Kepulauan Seribu. The research was carried out in February 2019. This research used quantitative field observation with the purposive sampling method. Samples were collected from 3 locations with nine stations. The obtained samples were analyzed at the Laboratory of Faculty of Fisheries and Marine Science, Diponegoro University. Carbon and sediment samples were analyzed using Loss in the Ignition (LOI) method. The results showed that there are three species of seagrass in Pari Island, i.e. Enhalus acoroides, Thalassia hemprichii, and Cymodocea rotundata. Total density value was 129.19 individual m−2 and total coverage value was 62.59%. Total stock potential of carbon value in Pari Island was 87.80 ton per ha with total area of seagrass meadows of 3.48 ha. Silty-sands mainly dominated sediment textures. It can be concluded that seagrass meadows are potential habitats to control CO2 concentration in coastal waters and to hold the rate of climate change.

Structure of macroinvertebrate communities and bioassessment of water quality in the Weihe River mainstream and its typical tributaries from the northern Qinling Mountains

为摸清渭河干流及源于秦岭北麓典型支流的大型底栖动物群落特征，本研究于2017年10月和2018年5月对渭河干流及秦岭北麓5条典型支流共40个样点的大型底栖动物进行调查，并利用Margalef丰富度指数和生物指数BI生物指数对河流水质进行评价.共鉴定大型底栖动物210种，属于5门8纲75科187属.水生昆虫为优势类群，其物种数占总物种数的89.0%，且四节蜉属一种（Baetis sp.）作为绝对优势的物种出现在所有调查河流中.源于秦岭北麓的支流石头河底栖动物总密度最高（616.3 ind./m²），总生物量最大（5.265 g/m²）；而渭河干流底栖动物总密度最低（125.6 ind./m²），总生物量最小（0.289 g/m²）.水质较好的秦岭北麓典型支流底栖动物的Shannon-Wiener多样性指数、Margalef丰富度指数显著高于渭河干流，而Pielou均匀度指数在干支流间的差异性不大.通过Pearson相关分析和多元逐步回归分析得出，淤泥型底质、电导率、pH和硝酸盐氮是影响调查河流底栖动物群落特征的主导因子.丰富度指数法和生物指数法水质评价结果分别显示，渭河干流有73.3%和80.0%的采样点呈中度-重度污染状态，秦岭北麓典型支流有80.0%和68.0%的采样点呈无污染-轻度污染状态.本研究可为渭河流域生态管理与保护提供基础的数据支撑.;For exploring the macroinvertebrate community characteristics of the Weihe River mainstream and its typical tributaries originating from the northern Qinling Mountains, investigation of water environment and macroinvertebrates was conducted in 40 sampling sites in October 2017 and May 2018. Furthermore, Margalef richness and biological index (BI) biological indices were used to assess the water quality of studied rivers. Altogether 210 macroinvertebrates species were identified, belonging to 187 genera, 75 families, 8 classes and 5 phyla. Aquatic insects were the dominant group, accounting for 89.0% of the total species number, and the Baetis sp. was the dominant species in all studied rivers. The tributary Shitou River, had the highest values of total density(616.3 ind./m²), and the highest total biomass(5.265 g/m²). Whereas the total density (125.6 ind./m²) and total biomass (0.289 g/m²) of macroinvertebrates were both lowest in the Weihe River mainstream. The Shannon-Wiener diversity index(H')and Margalef richness index(R)of five typical tributaries were characterized by good water quality and significantly higher than those of the Weihe River mainstream, whereas the Pielou evenness index(J)showed insignificant difference between mainstream and tributaries. Pearson correlation analysis and the multiple linear regression analysis showed that “Silt plus clay” type substrate, conductivity, pH and nitrate nitrogen were the primary environment factors effecting the macroinvertebrate community characteristics in studied rivers. According to the water quality evaluation results of the richness index and the BI method, 73.3% and 80.0% of the mainstream sites were identified as moderately to heavily polluted, but 80.0% and 68.0% of tributary sites were identified as non-polluted to slightly polluted. This study can provide basic data supports for ecological management and protection in the Weihe River Basin.

INFLUENCE OF ACICULAS DEPOSITION ON NATURAL REGENERATION IN SUB-WOODS OF Pinus taeda L. FOREST STAND

This study was conducted in a commercial forest stand of Pinus taeda L. located in Curitibanos, in the State of Santa Catarina, Brazil. The objective of this study was to evaluate the influence of the physical barrier caused by the deposition of aciculas, on natural regeneration mechanisms of native species in sub-woods of P. taeda L. forest stand. Three plots (10 x 10 m) were installed in the sub-woods of the forest stand, and the natural regeneration was evaluated in the control (presence of aciculas) and clean (absence of aciculas) subplots, in addition to the seeds rain and soil seeds bank. The density and frequency parameters (absolute and relative) and the Shannon-Weaver Index (H’) were calculated, and the total density values of the seeds rain and seeds bank were subjected to ANOVA (p<0.05), while the density of regenerative seedlings was subjected to Student’s t Test (p<0.05), using the Software R Studio ®. The density of regenerative seedlings (ind.m-2) was higher in clean subplots, statistically. No significant statistical difference was observed for the density parameter (ind.m-2) among the subplots for the soil seeds bank, but only for the seeds rain. Shannon Diversity Index was higher in the plots closer to the fragment in all evaluated mechanisms. The obtained results indicate that the litter layer acts as a physical barrier to the breeding of the seeds bank and prevents the arrival of the seeds rain propagules directly to the soil, hindering the establishment of native plants and, consequently, the natural regeneration in the sub-woods.

Effects of a shipwreck on the zooplankton community in a port region of the Amazon

The port regions of the Amazon are subject to environmental impacts high shipping traffic. In October 2015, a cargo ship containing 5000 oxen sank in the Port of Vila do Conde, northern Brazil, releasing large amounts of organic matter and diesel oil into the aquatic environment. We evaluated the consequences of this shipwreck on the zooplankton community. Sampling was carried out using a phytoplankton net (64 μm) at two locations close to the port. We calculated the frequency of occurrence, relative abundance, and trophic state index and performed a canonical redundancy analysis of zooplankton in this area. Total density values ranged from 371 to 8600 organisms/m3, with minimum values being recorded during the period of the shipwreck and maximum values after the shipwreck. The areas categorized as super eutrophic had the lowest density values. The most abundant species/groups were nauplii and copepodites of the orders Cyclopoida and Calanoida. Of the environmental variables, only biochemical oxygen demand, chemical oxygen demand, and total dissolved solids were selected by the redundancy canonical analysis. The environmental conditions of the region and the ongoing environmental impacts might substantially influence the structure of the zooplankton community. The predominance of these organisms, in addition to the high densities of nauplii and copepodites, was likely related to the large amounts of nutrients generated by the shipwreck.

Revealing the stability, elastic properties and electronic structures of Pd-V intermetallics via first principle calculations

Precious metals and their alloys are promising high-temperature materials due to the high melting point, high strength and thermodynamically stability, in which Pd-V alloys are one kind of important systems. However, the influence of V concentration on structure stability, mechanical and thermodynamic properties and chemical bonding of Pd-V compounds is unknown. The structures, elastic properties, anisotropic of elastic and electronic structures of thirteen Pd-V compounds as a function of V concentration have been investigated by first principle calculations in this work. We have determined all the possible stable phases of Pd-V system for the first time by thermodynamics convex hull and phonon spectrum. The calculated results show that α-Pd2V has the lowest formation enthalpies as -0.34 eV/atom, indicating more thermodynamically stable than other structures. The elastic constants, bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio of the Pd-V compounds are also calculated and the β-Pd3V has the largest shear modulus and Young’s modulus as 107.1 GPa and 275.7 GPa, respectively. The anisotropic mechanical properties of these Pd-V compounds are discussed in detailed by the anisotropic index, three-dimensional (3D) surface contours and the planer projections on (001) and (110) planes of the Young’s modulus. The values of total density of states (TDOS) of all compounds are nonzero at Fermi energy (EF), indicating metallic feature for all the Pd-V compounds.

COLONIZATION BY MACROINVERTEBRATES ON AN ARTIFICIAL SUBSTRATE AND COMPARISON WITH A NATURAL SUBSTRATE IN A FLOODPLAIN: A SHORT TIME STUDY IN THE RAINY SEASON

Understanding how the process of colonization by taxa in different types of habitat takes place is necessary to preserve their diversity. The aim of this study was to analyze the process of colonization by macroinvertebrates on an artificial substrate with morphology similar to that of the roots of aquatic macrophytes Ricciocarpus natans and Spirodela intermedia , which were present in the environment investigated. The hypothesis is that the values of total density on the artificial substrate will show a tendency similar to that of a macrophyte stand, but with a different taxonomic composition. The differences in taxa density and composition associated with the artificial substrate and macrophytes were significant. The total density and richness on the artificial substrate did not follow an upward curve with a significant increase in the number of individuals during the experiment, probably due to the heavy rainfall observed. The variation in the density values in both substrates shows that the macroinvertebrate community was maintained through an "emigration" and "immigration" dynamic. Our hypothesis was confirmed only in relation to the taxonomic composition. The colonization of the artificial substrate by macroinvertebrates might have been more efficient had the environment not received frequent rains, which affected the physical stability of the macroinvertebrate community. Therefore, intrinsic sampling site characteristics may have attenuated the effect of the flood pulse on the macroinvertebrate communities, since only oscillations in the density values of the taxa were observed, rather than their exclusion.

Variación nictemeral de los ensamblajes de macrocrustáceos en una playa arenosa del centro-norte de Veracruz, México

In this study, the structure of spatio-temporal variations of macrocrustacean assemblage were analyzed from the sandy beaches of Villa Rica, Veracruz. The nictemeral cycles related to lunar phases were taken into account; the non-metric multidimensional analysis showed an environmental stability trend. Within the macrocrustacean assemblages 9 species were recognized, of these, Emerita benedicti, Excirolana braziliensis, Excirolana sp. and Pseudohaustorius sp., were the dominant ones. The highest values of total density, species richness, and diversity were recorded during high tides. The cirolanid isopods and Emerita benedicti occurred in the lower unsaturated zone of the beach, and Pseudohaustorius sp. was found in the middle area. Macrocrustacean assemblage is simple, with low species richness (3-5) and low diversity values with significant differences throughout the study time; however, the assemblage structure complexity tended to be constant throughout time.

Influence of beach morphodynamics on the bivalve Donax hanleyanus and Mesodesma mactroides populations in Argentina

AbstractFive exposed microtidal sandy beaches of North‐eastern Buenos Aires (Argentina) were analysed to evaluate the influence of coastal dynamics on the abundance of the intertidal clams Donax hanleyanus and Mesodesma mactroides over a 1‐year period. The physical characterisation of each beach was performed using 15 environmental variables and six morphodynamic indices. The population densities of both clam species were estimated by the number of individuals per strip‐transect. Analysis of similarities revealed a significant multivariate environmental difference among beaches, which could be aggregated into a northern and a southern group. The former group was characterised by an intermediate morphodynamic state and by having, in general, high density values for both clam species. The latter was composed of beaches with an intermediate reflective state and showed, in general, low density values. Beach Index and Area showed the lowest temporal variation. Total density values, as well as density values of recruits and adults of D. hanleyanus and M. mactroides did not follow a north–south latitudinal gradient. Spatial and temporal fluctuations of density values were best explained by changes in individual physical variables rather than by changes in composite indices.

A taxonomical and environmental study of the genus Brachionus (Rotifera: Monogononta) (Pallas, 1776) in Al-Hammer marsh, south of Iraq

Samples of Rotifera genus Brachionus were collected from Al-Barka and Al-Nagara region in AlHammar Marsh, South of Iraq. Remarks on the taxonomy were notes on 6 species of the genus and a monthly density of each species were recorded during the study period from Feb-2006 to Jan-2007.The highest value of total density was 2.78 ind /l recorded in May -2006, whereas the lowest value was 0.01 ind /l and reported in March-2006.

Three dimensional morphometric analyses of axon terminals early changes induced by methylmercury intoxication in the adult cat striate cortex

The aim of the present report is to investigate in detail morphometric changes of axon terminals of area 17 of adult cat induced by methylmercury intoxication. Six adult male cats ( Felix catus), with 12 h day–light cycle and ad libitum water and food regimen, received a single dose of MeHgCl (6.4 mg/kg) dissolved in milk, whereas control subjects ( n = 6) received only milk. After 30 days, biocytin iontophoretic injections were done into the area 17, (Horsley-Clark coordinates between AP 3.0–6.0) on the crown of the lateral gyrus, near the border with area 18. MeHg and inorganic Hg (Hgi) concentrations were measured in the brain parenchyma of intoxicated cats and corresponded on average to 1.39 ± 0.3 and 6.79 ± 0.6 ppm (mean ± s.e.m.) respectively. Twenty four hours after iontophoresis, aldehyde fixed brain sections (200 μm thick), were processed to reveal biocytin labeled terminals. Axonal microscopic 3D reconstructions using Neurolucida software (Microbright Systems Inc.) allowed estimations of boutons, branching points and segment densities for each terminal. Cluster analysis of morphometric axonal features from control and intoxicated group revealed, two distinct axon families (Type I and II) as described elsewhere. Total density values of boutons, branching points and segment densities of intoxicated group, decreased 81, 59 and 91% respectively, as compared to the control group (ANOVA two-way, Bonferroni a priori test p < 0.05). Altered axonal morphology associated with MeHg, appeared early in the disease (30 days after contamination), revealing new aspects of the neuronal pathology of the methylmercury intoxication in the visual cortex.

Plant and soil diversities in a sub tropical forest of the Garhwal Himalaya

The forest plays a significant role in influencing the structure of the soil by adding organic matter and also affects its basic status and nutrient level. The ability of the soil to retain and the percolation of water depend upon the percent amount of sand, silt and clay. Biotic disturbances generally have caused substantial reduction in forest cover. It has been observed that among the aspects the regeneration status of species was poor. A number of studies relating to regeneration of either specific species or the forest stand as a whole have focused on the impact of anthropogenic factors and natural disturbances. In general, human interference and other causative factors such as grazing, browsing, trampling are severely affecting the regeneration of this region. The study sites were dominated by Anogeissus latifolia, which is the most important fodder, fuel wood and timber tree for local people. Therefore, the heavy pressure of villagers by lopping of leaves, cutting new saplings and tree branches especially for firewood, are leading to poor regeneration. Among the aspects the average range of values of soil pH (6.33 to 6.47), soil organic carbon (0.47 to 0.68 %), phosphorus (9.67 to 10.67 Kg ha-1) and potassium (141.87 to 172.48 Kg ha-1) were recorded. The total highest density of tree layer (380 trees ha-1) was observed on south aspect, whereas the lowest (260 trees ha-1) was recorded on west aspect. In shrub layer, the total highest density (1790 shrubs ha-1) was recorded on east aspect and the lowest (970 shrubs ha-1) on west aspect. The range of values of total density and total basal cover of saplings were 200 to 550 saplings ha-1 and 0.78 to 1.43 m2 ha-1 respectively. Similarly for seedlings layer, these values ranged from 80 to 430 seedlings ha-1 and 0.01 to 0.034 m2 ha-1 respectively. The values of similarity among the aspects and different layers ranged from 25.0 to 66.67%, 22.22 to 57.14%, 28.57 to 57.14% and 57.14 % to 72.72% for trees, saplings, seedlings and shrubs respectively. The range of diversity was 0.846 to 1.710 (trees), 1.943 to 2.847 (shrubs), 1.10 to 1.520 (saplings) and 0.496 to 1.435 (seedlings). Keywords: Diversity, disturbance, layer, Anogeissus latifolia, Garhwal Himalaya Ghana Journal of Forestry Vol. 19 & 20 2006: pp. 1-19