The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangla- desh in m...The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangla- desh in monsoon tropical climate. Clear felled area or burnt site and 15-21 year mixed plantation of native and exotic species, situated side by side on low hill having Typic Dystrochrepts soil was represented at each pair site. At all the three pair sites, clear felled area or burnt site showed very significantly (p~_0.001) lower population of actinomycetes, Rhizobium, Nitrosomonas, Nitrobacter and ammonifying as well as deni- trifying bacteria compared to their adjacent mixed plantation. From en- vironmental consideration, this finding has implication in managing natural ecosystem.展开更多
Soil samples were collected and analyzed from 25 sites of three hilly regions (Rangamati, Banderban and Khagrachari) for an understanding of the impact of denudation and land use on soils in Chittagong Hill Tracts, ...Soil samples were collected and analyzed from 25 sites of three hilly regions (Rangamati, Banderban and Khagrachari) for an understanding of the impact of denudation and land use on soils in Chittagong Hill Tracts, Bangladesh. There were natural forests, bushy land, slashed sites, slashed and burnt sites, and the sites prepared for shifting cultivation, one year after shifting cultivation and two years after shifting cultivation. The soils were generally yellowish brown to reddish brown, sandy to sandy clay loam, strongly acid, and well to excessively drained on steep slopes with considerable variation among the sites and land use categories. Bulk density was the highest in sites of one year after shifting cultivation (1.52 g·cm^-3) and the lowest in forested sites (1.38 g·cm^-3). Water holding capacities were, however, statistically similar in all sites. Organic carbon varied from 0.54% (slashed and burnt sites) to 1.55% (forested sites) and total N ranged from 0.05% (shifting cultivation for one year) to 0.13% (forested sites). Available phosphorus (Bray & Kurtz-2 P) was the maximum in forested sites (12.32 mg·kg^-l), and it did not differ significantly in other sites. Contents of available Ca, Mg and K were also higher in the bushy lands and forested sites than cleared and shifting cultivated sites.展开更多
We investigated the floristic composition, woody species diversity and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracks, Bangladesh. We recorded 25 fam...We investigated the floristic composition, woody species diversity and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracks, Bangladesh. We recorded 25 families, 37 genera, 40 species and 1771 woody individuals in a 0.09 ha plot. Euphorbiaceae and Moraceae were the most species- rich families, and Castanopsis, Ficus and Terminaliawere the most species-rich genera. Bursera serrata Wall. ex Colebr. was the dominant species in terms of highest importance value (13%). Trema orientalis (L.) B1 was typically a light demanding species as it appeared in the top can- opy with only one individual having the seventh highest IV, but had no regeneration. The expected maximum number of species (Smax) was 140, indicating that many species may invade the forest as the Sm~ is greater than the recorded total number of species. The nature of the disappear- ance and appearance of species in the present forest reflects instability of floristic composition. The values of Shannon's index H' and Pielou's index J' (evenness) were 3.36 bit and 0.63, respectively. These values show moderately high species diversity as compared to other subtropical forests in the tropics. In addition, a sample area of 200 m2 in this forest would be sufficient for measuring the diversity indices H" and ,/', whereas the trend of J'may indicate the rate of equality of individuals among the different species decreased with increasing area. The distribu- tion pattern for the total stand was completely random. However, the dominant species showed aggregate distribution for small areas, but random distribution for large areas. The spatial association between species showed that the strongest positive interspecific association occurred between Streblus asper Lour. and Castanea indica Roxh. (09 = 0.51). As a whole, most species were weakly associated with each other, of which 58% species associations were completely negative. The result of cluster analysis showed that species pairs were spatially independent at all or most small clusters; stands of species from all clusters are mosa- ics of complete habitat and pioneer habitat. All patches in this forest community have similar habitat and regeneration niches, which could be a phenomenon for a young growth forest. Thus, the existence of habitat and regeneration niches may be an important factor in the maintenance of diversity in this forest.展开更多
A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings ...A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings were from middle part of the reservoir at 0.2 and 0.8 fractional depths at five different locations from upstream to downstream viz. Burburichara, Maichchari, Subolong, Basanthakum, and Rangamati. Water analyses show that concentrations of NO3-N, K+ and total P, and suspended solid at all the sampling stations were beyond the recommended values for fish culture. Concentrations of Na^+, Ca^2+, Mg^2+, SO4^2-, Cl^-, total dissolved solid (TDS), dissolved oxygen (DO) and chemical oxygen demand (COD) were within the standards for aquaculture. Concentrations of NO3-N, SO4^2-, K+ and total P showed no definite trend with depths, locations as well as rainy and dry seasons. Water pH, conductivity, Na^+ and HCO3- contents were lower in rainy season, and DO and COD higher at almost all the locations in both the depths, compared with dry season. Total solids and concentrations of TDS, DO, COD, Ca^2+, Mg^2+ and Na^+ were higher in upstream and decreased gradually towards downstream in the reservoir. Concentrations of DO and Ca2+ and pH were higher and Mg2+ less at 0.2-fractional depth than those at 0.8-fractional depth at almost all the locations. The reservoir is in mesotrophic condition containing high concentration of NO3-N and total P, in alarming status with the presence of excessive suspended solids from urban pollution around the town. It is necessary to adopt measures for protecting water quality in the reservoir due to such deteriorations.展开更多
Abstract: We report the effects of shifting cultivation on water quality in 16 creeks investigated once in 2007 and twice in 2008 in 16 apparently similar small neighboring watersheds, each of 3 to 5 ha, at four loca...Abstract: We report the effects of shifting cultivation on water quality in 16 creeks investigated once in 2007 and twice in 2008 in 16 apparently similar small neighboring watersheds, each of 3 to 5 ha, at four locations around Barkal sub-district under Rangamati District of Chittagong Hill Tracts in Bangladesh. Concentrations of 5042- and K+, and pH in creek water were lower, and NO3-N and Na+ concentrations were higher in shifting-cultivation land compared to land with either plantation or natu- ral forest or a combination of these cover types. Shifting cultivation effects on some water quality parameters were not significant due to change in land cover of the watershed between two sampling periods either through introduction of planted tree species or naturally regenerated vegetation. Conductivity and concentrations of HCO3- PO43-, Ca2-- and Mg2+ in creek water showed no definite trend between shifting cultivation and the other land cover types. At one area near the Forest Range Office of Barkal, creek water pH was 5.8 under land cover with a com- bination of shifting cultivation and plantation. At this area Na~ concentra- tion in shitting-cultivation land ranged from 32.33 to 33.00 mg-L" and in vegetated area from 25.00 to 30.50 mg.L-1 in 2007. At another area, Chaliatali Chara, SO42 concentration in a shifting-cultivation watershed ranged from 4.46 to 10.51 mg-L-1, lower than in a vegetated watershed that ranged from 11.69 to 19.98 mg.L-1 in 2007. S042-concentration in this shifting-cultivation area ranged from 1.28 to 1.37 mg.L^-1 and in the vegetated area from 1.37 to 3.50 mg-L^-1 in 2008.展开更多
This study was conducted to investigate the historical management system of village common forests (VCF) in the Chittagong Hill Tracts (CHT) of Bangladesh and observe the current issues related to their sustainability...This study was conducted to investigate the historical management system of village common forests (VCF) in the Chittagong Hill Tracts (CHT) of Bangladesh and observe the current issues related to their sustainability. The study on historical context was based on secondary information to establish the linkages of VCF development and management in the CHT. Field visits to four VCF in the Bandarban Hill Districts were also conducted to cross check the information collected from secondary sources to observe the current status and management pattern of these VCF through semi-structured interviews, group discussion, key-informant interviews and biodiversity assessment. VCF in the CHT undoubtedly play an important role in biodiversity conservation and as well as supporting daily necessities of the community people. We found that VCF still are the source of fuel wood, herbs, roots, bamboo shoots, wild fruits, vines or leaves for cooking or medicinal use necessary to sustain the lives of the indigenous communities in the CHT. Field visits to different VCF show that the VCF are necessarily small in size (57 ha) and around 108 families are dependent on these community managed village forests. A total of 163 plant species from 60 families were also recorded from these VCF including some rare plant and animal species which are not usually found in the reserve forests and the un-classed state forests due to continued deforestation and land degradation. However, population pressure combined with improved marketing facilities, ignorance, over exploitation, personal greed, tenure insecurity, faulty government policies regarding settlement of land and breakdown of the traditional systems exerting pressures on these VCF and the overall condition of these important biodiversity rich areas are degrading or shrinking in size and number gradually. Recognizing the traditional and customary resource rights of the indigenous communities in the CHT, acknowledging resource management system, providing tenure security, encouraging communities through legal and financial incentives in protecting these VCF or any other state owned forest areas solely for the conservation of biodiversity following an intensive management plan, resolving long lasting land related conflicts, and at the same time upholding the spirit of CHT Peace Accord 1997 could be important policy tools for the sustainability of these VCF in the CHT. Lessons learned from this study will be useful in formulating effective policies for community based forest management in Bangladesh and other developing countries.展开更多
Since creation of spatial data is a costly and time consuming process, researchers, in this domain, in most of the cases rely on open source spatial attributes for their specific purpose. Likewise, the present researc...Since creation of spatial data is a costly and time consuming process, researchers, in this domain, in most of the cases rely on open source spatial attributes for their specific purpose. Likewise, the present research aims at mapping landslide susceptibility at the metropolitan area of Chittagong district of Bangladesh utilizing obtainable open source spatial data from various web portals. In this regard, we targeted a study region where rainfall induced landslides reportedly causes causalities as well as property damage each year. In this study, however, we employed multi-criteria evaluation (MCE) technique i.e., heuristic, a knowledge driven approach based on expert opinions from various discipline for landslide susceptibility mapping combining nine causative factors—geomorphology, geology, land use/land cover (LULC), slope, aspect, plan curvature, drainage distance, relative relief and vegetation in geographic information system (GIS) environment. The final susceptibility map was devised into five hazard classes viz., very low, low, moderate, high, and very high, representing 22 km2 (13%), 90 km2 (53%);24 km2 (15%);22 km2 (13%) and 10 km2 (6%) areas respectively. This particular study might be beneficial to the local authorities and other stake-holders, concerned in disaster risk reduction and mitigation activities. Moreover this study can also be advantageous for risk sensitive land use planning in the study area.展开更多
Red Chittagong Cattle (RCC) is one of the renowned varieties of cattle which is indigenous and most potential type of domestic animal genetic resource in Bangladesh with distinct phenotypic characteristics. Reproducti...Red Chittagong Cattle (RCC) is one of the renowned varieties of cattle which is indigenous and most potential type of domestic animal genetic resource in Bangladesh with distinct phenotypic characteristics. Reproductive management might be a process for multiplying this cattle variety. Therefore, the goals of this study were to characterize the follicular waves of RCC and to determine the Progesterone (P4), Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) profile during three consecutive estrus cycle. Follicular wave emergence (Day 0) was identified using trans-vaginal ultrasound technique and follicular growth was then monitored from Day 0 to Day 23 during three consecutive estrus cycle and blood samples were collected. After measuring the growth and diameter of the follicles, hormonal assays of collected blood samples were performed using Enzyme Linked Immunosorbent Assay (ELISA). We found that, both RCC cows and heifers showed two waves inter-ovulatory intervals. The length of inter-ovulatory intervals and the diameter of the ovulatory follicle of RCC cows and heifers were slightly different from each other. The identification of the dominant follicle was confirmed from the start of its deviation from other subordinate follicles till it reached to the maximum diameter and identified as dominant follicle which increases linearly for approximately six days (growing phase). This dominant follicle is remained approximately same size for five days (static phase), and then begins to regress (regressing phase) decreasing the antral diameter. The follicular waves are first detectable as 4 - 5 mm follicles approximately at day 0 and day 10 both for RCC cows and heifers which showed two waves inter-ovulatory intervals. The circulating varied concentrations of LH, FSH and P4 were determined using ELISA in case of both cows and heifers and the concentration curves followed the similar pattern of change during the estrus cycle. Hence, the knowledge about ovarian follicular waves will create a base line for reproductive management of RCC as well as to allow reproductive biotechnologies to improve and multiply this cattle variety.展开更多
Bangladesh is a country with limited sources of energy and since 1990 natural gas has been its main source of energy. Most of the exploration approaches had been conducted onshore especially in the central and eastern...Bangladesh is a country with limited sources of energy and since 1990 natural gas has been its main source of energy. Most of the exploration approaches had been conducted onshore especially in the central and eastern part of Bangladesh, particularly in northeastern Sylhet basin. Among the hydrocarbon provinces, the East Delta Hill Tract province is an under explored petroleum province in Bangladesh. An exploratory well drilled in Sitakund anticline was found dry but no reasonable cause was perceived why that well went dry. Although many works had been carried out in Chittagong Hill Tracts but none of them was cumulative and descriptive. In this study, the overall hydrocarbon prospect of the Chittagong Hill Tracts was analyzed by mapping of potential zones on the basis of the evaluation of regional structure and construction of lithocolumn of the prospective zones. The five elements of the petroleum system discussed thoroughly to find overall petroleum prospect of the study area. Source rocks of Chittagong Hill Tracts are mainly Bhuban shale, reservoir rock is sandstone from Bhuban-Bokabil formation, the way of migration path is both through longitudinal and cross fault. The data of source rock and seal is collected from previous researches. Multiple types of traps have been found there. Conventional anticlinal traps which are highly disturbed due to tectonic instability & the core part are shale diapirism. Most of the anticlines are plunging and the nose or plunge area might be prospective to HC for being comparatively less faulted. Broad synclinal areas between tight narrow anticlines are another prospective area for HC. These similar types of synclines are also found in Tripura, India which is a highly prospective area for petroleum and their small anticlinal hums within syncline are also prospective. Some stratigraphic traps have also been found in Tripura from where production has been started already. Both Chittagong Hill Tracts and Tripura Fold Belts are parts of great Arakan Fold Belts, so similar type of structures might be prospective here. Apart from these, Bangladesh is a deltaic country. So stratigraphic trapment like channel sand, pinch-outs is possible. Considering all the elements of petroleum prospectivity of the area and factors discussed above, it is quite clear that Chittagong hill tracts might be the next target for HC exploration program.展开更多
对孟加拉国丘陵地带Mro部落经营的桔园与灌木林35%和55%两种坡地土壤物理性质进行了比较与评价。每一块用地内挖掘3个土壤剖面采集不同深度(0-5cm,5-15cm and 15-30cm)的土壤样品,测定土壤水分、有机质含量和土壤密度。最大持水量、田...对孟加拉国丘陵地带Mro部落经营的桔园与灌木林35%和55%两种坡地土壤物理性质进行了比较与评价。每一块用地内挖掘3个土壤剖面采集不同深度(0-5cm,5-15cm and 15-30cm)的土壤样品,测定土壤水分、有机质含量和土壤密度。最大持水量、田间持水量、干或湿土壤容重和土壤孔隙度的测定仅限于表层土壤。两种坡地桔园3个深度的土壤水分含量均显著高于灌木林地相同深度的土壤水分。桔园在55%坡地内土壤有机质含量低于林地含量值,而在35%坡地内的含量值则高于林地值。两块样地内上述两项测定值均在表层土壤中最高,且随土层深度的增加而降低。与灌木林地比较,桔园地表层土壤最大持水量、孔隙度和3个不同深度的土壤密度均较低。两块用地内不同坡地的表层土田间持水量有所差异,且桔园地干或湿表层土壤容重高于林地内的数值。表5参23。展开更多
We collected soil samples from two representative sites at Aatmile of Khagarachari hill district in Chittagong Hill Tracts. One of the sites was under shifting cultivation and the other an adjacent 13-year old teak pl...We collected soil samples from two representative sites at Aatmile of Khagarachari hill district in Chittagong Hill Tracts. One of the sites was under shifting cultivation and the other an adjacent 13-year old teak plantation. Both sites were in the same physiographic condition and same aspect with parable soil type, which enabled us to measure the effects of shifting cultivation on soil micro-flora. We studied soil phys-ico-chemical properties and the biochemical and biological properties of soil microbes. Moisture and organic matter content as well as fungi and bacterial populations, both in surface and subsurface soils, were signifi-cantly (p≤0.001) lower in shifting cultivated soils compared to soils not under shifting cultivation, i.e. the teak plantation site. The most abundant bacteria in surface (0-10 cm) and sub-surface (10-20 cm) soils under shifting cultivation were Pseudomonas diminuta and Shigella, respec-tively, while in corresponding soil layers of teak plantation, predominant microbes were Bacillus firmus (0-10 cm) and Xanthomonas (10-20 cm). The microbial population differences cannot be explained by soil texture differences because of the textural similarity in soils from the two sites but could be related to the significantly lower moisture and organic mat-ter contents in soils under shifting cultivation.展开更多
This study reports the effects of shifting cultivation at slashing stage on soil physicochemical properties at Bandarban Sadar Upazila in Chittagong Hill Tracts of Bangladesh. At this initial stage of shifting cultiva...This study reports the effects of shifting cultivation at slashing stage on soil physicochemical properties at Bandarban Sadar Upazila in Chittagong Hill Tracts of Bangladesh. At this initial stage of shifting cultivation no general trend was found for moisture content, maximum water holding capacity, field capacity, dry and moist bulk density, parti- cle density for some chemical properties between shifting cultivated land and forest having similar soil texture. Organic matter was significantly 0.05) lower in 1-year and 3-year shifting cultivated lands and higher in 2-year shifting cultivation than in adjacent natural forest. Significant differences were also found for total N, exchangeable Ca, Mg and K and in CEC as well as for available P. Slashed area showed higher soil pH. Deterioration in land quality starts from burning of slashing materials and continues through subsequent stages of shifting cultivation.展开更多
Shifting cultivation is a traditional farming system practiced in the tropical mountainous areas. Although it has been widely perceived as an economically inefficient and environmentally harmful agricultural productio...Shifting cultivation is a traditional farming system practiced in the tropical mountainous areas. Although it has been widely perceived as an economically inefficient and environmentally harmful agricultural production system, recent science reviews, however, indicate that the deleterious impacts of shifting cultivation on environment may have been overestimated. Despite the pressures of agricultural intensification in areas where shifting cultivation occurs, farmers across the tropics still maintain this traditional farming system. The objective of this study was to explore existing traditional shifting cultivation practices and their various modifications including the innovative farming techniques developed by farmers in the Chittagong Hill Tracts(CHTs), the mountainous region of Bangladesh, and examine their importance with respect to recent socio-economic and environmental changes. The study revealed that shifting cultivation still exists as the most dominant farming method which supports livelihoods and culture of the hill ethnic people. However, demand for more food and household income to meet livelihood needs of an increasing population combined with a rapid deterioration of soil and water quality over decades contributed to development of innovative farming practices through fallow land farming, crop substitution, agroforestry and homestead gardening in the CHTs. Through these farming techniques farmers maintain a strong relationship with traditional knowledge system embedded in the ageold shifting cultivation practices. Today state policies and market forces act in favor of replacement of traditional farming with intensive cash crop agriculture. It seems that disappearance of traditional farming practices from the hills may threaten local biodiversity and food security. It may be recommended that shifting cultivation should be encouraged in areas where they have potential for contributing to preservation of native biodiversity and ecosystem services, and protection of local peoples' food security and cultural identity.展开更多
Objective:Skin diseases are common and striking features of patients with human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)and may vary considerably by ethnic and geographic regions and by the ...Objective:Skin diseases are common and striking features of patients with human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)and may vary considerably by ethnic and geographic regions and by the influence of highly active antiretroviral therapy(HAART).However,little information exists regarding the cutaneous manifestations of patients with HIV/AIDS in Bangladesh.This study was performed to elucidate the spectrum of cutaneous disorders in patients with HIV/AIDS in the era of HAART.Materials:This descriptive cross-sectional study was carried out in Chittagong Medical College Hospital,Bangladesh from January 2017 and December 2020.Diagnosed case of HIV/AIDS for HAART therapy and all cases of HIV/AIDS who are already on HAART therapy were included in this study.Descriptive statistical analysis was carried out by using frequencies and percentages.Results:Of 40 patients with HIV/AIDS,22(55.0%)were male and 18(45.0%)were female.The patients ranged in age from 8 to 60 years,with a mean age of 38±0.966 years.Among all age groups,the highest 19(47.5%)patients were in the 31-to 40-year age group.Most of the patients were migrant workers[22/40(55.0%)]with low socioeconomic status[32/40(80.0%)],and the most common transmission mode was heterosexual activity[36/40(90.0%)].Most of the patients[32/40(80.0%)]had mucocutaneous disorders,30/40(75.0%)had infective dermatoses,and 21/40(52.5%)had non-infective inflammatory dermatoses.Eight of forty(20.0%)patients presented with three or more skin disorders.The most common infective dermatoses were fungal infections[15/40(37.5%)],followed by viral infections[8/40(20.0%)],bacterial infections[4/40(10.0%)],and scabies[3/40(7.5%)].The most common non-infective dermatosis was generalized pruritus[6/40(15.0%)],followed by prurigo simplex[4/40(10.0%)],psoriasis[4/40(10.0%)],eczema[3/40(7.5%)],pruritic papular eruption[1/40(2.5%)],seborrheic dermatitis[1/40(2.5%)],urticaria[1/40(2.5%)],and xerosis[1/40(2.5%)].Patients treated with HAART had decreased rates of oral candidiasis and herpes simplex but increased rates of drug reactions[19/40(47.5%)].The most common drug eruption following HAART was a morbilliform rash[11/40(27.5%)],and the most common offending agent was nevirapine.The prevalence of mucocutaneous disorders was higher in patients with a CD4 cell count of<200 cells/mm3.Conclusions:A wide range of mucocutaneous disorders is observed in Bangladeshi patients with HIV/AIDS,and HAART has an impact on the spectrum of HIV/AIDS-associated mucocutaneous disorders.Skin and mucocutaneous disorders are seen at every stage of HIV/AIDS and are the initial presentation in most patients in Bangladesh.There is a need for increased attention to the diagnosis and treatment of skin diseases affecting the quality of life of patients withHIV/AIDS.展开更多
文摘The effect of forests clear felling and associated burning on the population of soil nitrogen transforming bacteria and actinomycetes are reported at three pair sites of Chittagong University campus, Bangla- desh in monsoon tropical climate. Clear felled area or burnt site and 15-21 year mixed plantation of native and exotic species, situated side by side on low hill having Typic Dystrochrepts soil was represented at each pair site. At all the three pair sites, clear felled area or burnt site showed very significantly (p~_0.001) lower population of actinomycetes, Rhizobium, Nitrosomonas, Nitrobacter and ammonifying as well as deni- trifying bacteria compared to their adjacent mixed plantation. From en- vironmental consideration, this finding has implication in managing natural ecosystem.
文摘Soil samples were collected and analyzed from 25 sites of three hilly regions (Rangamati, Banderban and Khagrachari) for an understanding of the impact of denudation and land use on soils in Chittagong Hill Tracts, Bangladesh. There were natural forests, bushy land, slashed sites, slashed and burnt sites, and the sites prepared for shifting cultivation, one year after shifting cultivation and two years after shifting cultivation. The soils were generally yellowish brown to reddish brown, sandy to sandy clay loam, strongly acid, and well to excessively drained on steep slopes with considerable variation among the sites and land use categories. Bulk density was the highest in sites of one year after shifting cultivation (1.52 g·cm^-3) and the lowest in forested sites (1.38 g·cm^-3). Water holding capacities were, however, statistically similar in all sites. Organic carbon varied from 0.54% (slashed and burnt sites) to 1.55% (forested sites) and total N ranged from 0.05% (shifting cultivation for one year) to 0.13% (forested sites). Available phosphorus (Bray & Kurtz-2 P) was the maximum in forested sites (12.32 mg·kg^-l), and it did not differ significantly in other sites. Contents of available Ca, Mg and K were also higher in the bushy lands and forested sites than cleared and shifting cultivated sites.
文摘We investigated the floristic composition, woody species diversity and spatial distribution of trees in a tropical wet evergreen forest in Kaptai national park in Chittagong Hill Tracks, Bangladesh. We recorded 25 families, 37 genera, 40 species and 1771 woody individuals in a 0.09 ha plot. Euphorbiaceae and Moraceae were the most species- rich families, and Castanopsis, Ficus and Terminaliawere the most species-rich genera. Bursera serrata Wall. ex Colebr. was the dominant species in terms of highest importance value (13%). Trema orientalis (L.) B1 was typically a light demanding species as it appeared in the top can- opy with only one individual having the seventh highest IV, but had no regeneration. The expected maximum number of species (Smax) was 140, indicating that many species may invade the forest as the Sm~ is greater than the recorded total number of species. The nature of the disappear- ance and appearance of species in the present forest reflects instability of floristic composition. The values of Shannon's index H' and Pielou's index J' (evenness) were 3.36 bit and 0.63, respectively. These values show moderately high species diversity as compared to other subtropical forests in the tropics. In addition, a sample area of 200 m2 in this forest would be sufficient for measuring the diversity indices H" and ,/', whereas the trend of J'may indicate the rate of equality of individuals among the different species decreased with increasing area. The distribu- tion pattern for the total stand was completely random. However, the dominant species showed aggregate distribution for small areas, but random distribution for large areas. The spatial association between species showed that the strongest positive interspecific association occurred between Streblus asper Lour. and Castanea indica Roxh. (09 = 0.51). As a whole, most species were weakly associated with each other, of which 58% species associations were completely negative. The result of cluster analysis showed that species pairs were spatially independent at all or most small clusters; stands of species from all clusters are mosa- ics of complete habitat and pioneer habitat. All patches in this forest community have similar habitat and regeneration niches, which could be a phenomenon for a young growth forest. Thus, the existence of habitat and regeneration niches may be an important factor in the maintenance of diversity in this forest.
文摘A study was conducted in Kaptai reservoir, one of the largest man-made freshwater lakes of South-east Asia, to determine present status of water quality and its suitability for fishing and other uses. Water samplings were from middle part of the reservoir at 0.2 and 0.8 fractional depths at five different locations from upstream to downstream viz. Burburichara, Maichchari, Subolong, Basanthakum, and Rangamati. Water analyses show that concentrations of NO3-N, K+ and total P, and suspended solid at all the sampling stations were beyond the recommended values for fish culture. Concentrations of Na^+, Ca^2+, Mg^2+, SO4^2-, Cl^-, total dissolved solid (TDS), dissolved oxygen (DO) and chemical oxygen demand (COD) were within the standards for aquaculture. Concentrations of NO3-N, SO4^2-, K+ and total P showed no definite trend with depths, locations as well as rainy and dry seasons. Water pH, conductivity, Na^+ and HCO3- contents were lower in rainy season, and DO and COD higher at almost all the locations in both the depths, compared with dry season. Total solids and concentrations of TDS, DO, COD, Ca^2+, Mg^2+ and Na^+ were higher in upstream and decreased gradually towards downstream in the reservoir. Concentrations of DO and Ca2+ and pH were higher and Mg2+ less at 0.2-fractional depth than those at 0.8-fractional depth at almost all the locations. The reservoir is in mesotrophic condition containing high concentration of NO3-N and total P, in alarming status with the presence of excessive suspended solids from urban pollution around the town. It is necessary to adopt measures for protecting water quality in the reservoir due to such deteriorations.
文摘Abstract: We report the effects of shifting cultivation on water quality in 16 creeks investigated once in 2007 and twice in 2008 in 16 apparently similar small neighboring watersheds, each of 3 to 5 ha, at four locations around Barkal sub-district under Rangamati District of Chittagong Hill Tracts in Bangladesh. Concentrations of 5042- and K+, and pH in creek water were lower, and NO3-N and Na+ concentrations were higher in shifting-cultivation land compared to land with either plantation or natu- ral forest or a combination of these cover types. Shifting cultivation effects on some water quality parameters were not significant due to change in land cover of the watershed between two sampling periods either through introduction of planted tree species or naturally regenerated vegetation. Conductivity and concentrations of HCO3- PO43-, Ca2-- and Mg2+ in creek water showed no definite trend between shifting cultivation and the other land cover types. At one area near the Forest Range Office of Barkal, creek water pH was 5.8 under land cover with a com- bination of shifting cultivation and plantation. At this area Na~ concentra- tion in shitting-cultivation land ranged from 32.33 to 33.00 mg-L" and in vegetated area from 25.00 to 30.50 mg.L-1 in 2007. At another area, Chaliatali Chara, SO42 concentration in a shifting-cultivation watershed ranged from 4.46 to 10.51 mg-L-1, lower than in a vegetated watershed that ranged from 11.69 to 19.98 mg.L-1 in 2007. S042-concentration in this shifting-cultivation area ranged from 1.28 to 1.37 mg.L^-1 and in the vegetated area from 1.37 to 3.50 mg-L^-1 in 2008.
文摘This study was conducted to investigate the historical management system of village common forests (VCF) in the Chittagong Hill Tracts (CHT) of Bangladesh and observe the current issues related to their sustainability. The study on historical context was based on secondary information to establish the linkages of VCF development and management in the CHT. Field visits to four VCF in the Bandarban Hill Districts were also conducted to cross check the information collected from secondary sources to observe the current status and management pattern of these VCF through semi-structured interviews, group discussion, key-informant interviews and biodiversity assessment. VCF in the CHT undoubtedly play an important role in biodiversity conservation and as well as supporting daily necessities of the community people. We found that VCF still are the source of fuel wood, herbs, roots, bamboo shoots, wild fruits, vines or leaves for cooking or medicinal use necessary to sustain the lives of the indigenous communities in the CHT. Field visits to different VCF show that the VCF are necessarily small in size (57 ha) and around 108 families are dependent on these community managed village forests. A total of 163 plant species from 60 families were also recorded from these VCF including some rare plant and animal species which are not usually found in the reserve forests and the un-classed state forests due to continued deforestation and land degradation. However, population pressure combined with improved marketing facilities, ignorance, over exploitation, personal greed, tenure insecurity, faulty government policies regarding settlement of land and breakdown of the traditional systems exerting pressures on these VCF and the overall condition of these important biodiversity rich areas are degrading or shrinking in size and number gradually. Recognizing the traditional and customary resource rights of the indigenous communities in the CHT, acknowledging resource management system, providing tenure security, encouraging communities through legal and financial incentives in protecting these VCF or any other state owned forest areas solely for the conservation of biodiversity following an intensive management plan, resolving long lasting land related conflicts, and at the same time upholding the spirit of CHT Peace Accord 1997 could be important policy tools for the sustainability of these VCF in the CHT. Lessons learned from this study will be useful in formulating effective policies for community based forest management in Bangladesh and other developing countries.
文摘Since creation of spatial data is a costly and time consuming process, researchers, in this domain, in most of the cases rely on open source spatial attributes for their specific purpose. Likewise, the present research aims at mapping landslide susceptibility at the metropolitan area of Chittagong district of Bangladesh utilizing obtainable open source spatial data from various web portals. In this regard, we targeted a study region where rainfall induced landslides reportedly causes causalities as well as property damage each year. In this study, however, we employed multi-criteria evaluation (MCE) technique i.e., heuristic, a knowledge driven approach based on expert opinions from various discipline for landslide susceptibility mapping combining nine causative factors—geomorphology, geology, land use/land cover (LULC), slope, aspect, plan curvature, drainage distance, relative relief and vegetation in geographic information system (GIS) environment. The final susceptibility map was devised into five hazard classes viz., very low, low, moderate, high, and very high, representing 22 km2 (13%), 90 km2 (53%);24 km2 (15%);22 km2 (13%) and 10 km2 (6%) areas respectively. This particular study might be beneficial to the local authorities and other stake-holders, concerned in disaster risk reduction and mitigation activities. Moreover this study can also be advantageous for risk sensitive land use planning in the study area.
文摘Red Chittagong Cattle (RCC) is one of the renowned varieties of cattle which is indigenous and most potential type of domestic animal genetic resource in Bangladesh with distinct phenotypic characteristics. Reproductive management might be a process for multiplying this cattle variety. Therefore, the goals of this study were to characterize the follicular waves of RCC and to determine the Progesterone (P4), Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) profile during three consecutive estrus cycle. Follicular wave emergence (Day 0) was identified using trans-vaginal ultrasound technique and follicular growth was then monitored from Day 0 to Day 23 during three consecutive estrus cycle and blood samples were collected. After measuring the growth and diameter of the follicles, hormonal assays of collected blood samples were performed using Enzyme Linked Immunosorbent Assay (ELISA). We found that, both RCC cows and heifers showed two waves inter-ovulatory intervals. The length of inter-ovulatory intervals and the diameter of the ovulatory follicle of RCC cows and heifers were slightly different from each other. The identification of the dominant follicle was confirmed from the start of its deviation from other subordinate follicles till it reached to the maximum diameter and identified as dominant follicle which increases linearly for approximately six days (growing phase). This dominant follicle is remained approximately same size for five days (static phase), and then begins to regress (regressing phase) decreasing the antral diameter. The follicular waves are first detectable as 4 - 5 mm follicles approximately at day 0 and day 10 both for RCC cows and heifers which showed two waves inter-ovulatory intervals. The circulating varied concentrations of LH, FSH and P4 were determined using ELISA in case of both cows and heifers and the concentration curves followed the similar pattern of change during the estrus cycle. Hence, the knowledge about ovarian follicular waves will create a base line for reproductive management of RCC as well as to allow reproductive biotechnologies to improve and multiply this cattle variety.
文摘Bangladesh is a country with limited sources of energy and since 1990 natural gas has been its main source of energy. Most of the exploration approaches had been conducted onshore especially in the central and eastern part of Bangladesh, particularly in northeastern Sylhet basin. Among the hydrocarbon provinces, the East Delta Hill Tract province is an under explored petroleum province in Bangladesh. An exploratory well drilled in Sitakund anticline was found dry but no reasonable cause was perceived why that well went dry. Although many works had been carried out in Chittagong Hill Tracts but none of them was cumulative and descriptive. In this study, the overall hydrocarbon prospect of the Chittagong Hill Tracts was analyzed by mapping of potential zones on the basis of the evaluation of regional structure and construction of lithocolumn of the prospective zones. The five elements of the petroleum system discussed thoroughly to find overall petroleum prospect of the study area. Source rocks of Chittagong Hill Tracts are mainly Bhuban shale, reservoir rock is sandstone from Bhuban-Bokabil formation, the way of migration path is both through longitudinal and cross fault. The data of source rock and seal is collected from previous researches. Multiple types of traps have been found there. Conventional anticlinal traps which are highly disturbed due to tectonic instability & the core part are shale diapirism. Most of the anticlines are plunging and the nose or plunge area might be prospective to HC for being comparatively less faulted. Broad synclinal areas between tight narrow anticlines are another prospective area for HC. These similar types of synclines are also found in Tripura, India which is a highly prospective area for petroleum and their small anticlinal hums within syncline are also prospective. Some stratigraphic traps have also been found in Tripura from where production has been started already. Both Chittagong Hill Tracts and Tripura Fold Belts are parts of great Arakan Fold Belts, so similar type of structures might be prospective here. Apart from these, Bangladesh is a deltaic country. So stratigraphic trapment like channel sand, pinch-outs is possible. Considering all the elements of petroleum prospectivity of the area and factors discussed above, it is quite clear that Chittagong hill tracts might be the next target for HC exploration program.
文摘对孟加拉国丘陵地带Mro部落经营的桔园与灌木林35%和55%两种坡地土壤物理性质进行了比较与评价。每一块用地内挖掘3个土壤剖面采集不同深度(0-5cm,5-15cm and 15-30cm)的土壤样品,测定土壤水分、有机质含量和土壤密度。最大持水量、田间持水量、干或湿土壤容重和土壤孔隙度的测定仅限于表层土壤。两种坡地桔园3个深度的土壤水分含量均显著高于灌木林地相同深度的土壤水分。桔园在55%坡地内土壤有机质含量低于林地含量值,而在35%坡地内的含量值则高于林地值。两块样地内上述两项测定值均在表层土壤中最高,且随土层深度的增加而降低。与灌木林地比较,桔园地表层土壤最大持水量、孔隙度和3个不同深度的土壤密度均较低。两块用地内不同坡地的表层土田间持水量有所差异,且桔园地干或湿表层土壤容重高于林地内的数值。表5参23。
基金United States Department of Agriculture(USDA) for funding this research
文摘We collected soil samples from two representative sites at Aatmile of Khagarachari hill district in Chittagong Hill Tracts. One of the sites was under shifting cultivation and the other an adjacent 13-year old teak plantation. Both sites were in the same physiographic condition and same aspect with parable soil type, which enabled us to measure the effects of shifting cultivation on soil micro-flora. We studied soil phys-ico-chemical properties and the biochemical and biological properties of soil microbes. Moisture and organic matter content as well as fungi and bacterial populations, both in surface and subsurface soils, were signifi-cantly (p≤0.001) lower in shifting cultivated soils compared to soils not under shifting cultivation, i.e. the teak plantation site. The most abundant bacteria in surface (0-10 cm) and sub-surface (10-20 cm) soils under shifting cultivation were Pseudomonas diminuta and Shigella, respec-tively, while in corresponding soil layers of teak plantation, predominant microbes were Bacillus firmus (0-10 cm) and Xanthomonas (10-20 cm). The microbial population differences cannot be explained by soil texture differences because of the textural similarity in soils from the two sites but could be related to the significantly lower moisture and organic mat-ter contents in soils under shifting cultivation.
基金supported by United States Department of Agriculture(USDA)
文摘This study reports the effects of shifting cultivation at slashing stage on soil physicochemical properties at Bandarban Sadar Upazila in Chittagong Hill Tracts of Bangladesh. At this initial stage of shifting cultivation no general trend was found for moisture content, maximum water holding capacity, field capacity, dry and moist bulk density, parti- cle density for some chemical properties between shifting cultivated land and forest having similar soil texture. Organic matter was significantly 0.05) lower in 1-year and 3-year shifting cultivated lands and higher in 2-year shifting cultivation than in adjacent natural forest. Significant differences were also found for total N, exchangeable Ca, Mg and K and in CEC as well as for available P. Slashed area showed higher soil pH. Deterioration in land quality starts from burning of slashing materials and continues through subsequent stages of shifting cultivation.
基金the financial support provided by the Center for International Forestry Research (CIFOR) for conducting the fieldwork of this study
文摘Shifting cultivation is a traditional farming system practiced in the tropical mountainous areas. Although it has been widely perceived as an economically inefficient and environmentally harmful agricultural production system, recent science reviews, however, indicate that the deleterious impacts of shifting cultivation on environment may have been overestimated. Despite the pressures of agricultural intensification in areas where shifting cultivation occurs, farmers across the tropics still maintain this traditional farming system. The objective of this study was to explore existing traditional shifting cultivation practices and their various modifications including the innovative farming techniques developed by farmers in the Chittagong Hill Tracts(CHTs), the mountainous region of Bangladesh, and examine their importance with respect to recent socio-economic and environmental changes. The study revealed that shifting cultivation still exists as the most dominant farming method which supports livelihoods and culture of the hill ethnic people. However, demand for more food and household income to meet livelihood needs of an increasing population combined with a rapid deterioration of soil and water quality over decades contributed to development of innovative farming practices through fallow land farming, crop substitution, agroforestry and homestead gardening in the CHTs. Through these farming techniques farmers maintain a strong relationship with traditional knowledge system embedded in the ageold shifting cultivation practices. Today state policies and market forces act in favor of replacement of traditional farming with intensive cash crop agriculture. It seems that disappearance of traditional farming practices from the hills may threaten local biodiversity and food security. It may be recommended that shifting cultivation should be encouraged in areas where they have potential for contributing to preservation of native biodiversity and ecosystem services, and protection of local peoples' food security and cultural identity.
文摘Objective:Skin diseases are common and striking features of patients with human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)and may vary considerably by ethnic and geographic regions and by the influence of highly active antiretroviral therapy(HAART).However,little information exists regarding the cutaneous manifestations of patients with HIV/AIDS in Bangladesh.This study was performed to elucidate the spectrum of cutaneous disorders in patients with HIV/AIDS in the era of HAART.Materials:This descriptive cross-sectional study was carried out in Chittagong Medical College Hospital,Bangladesh from January 2017 and December 2020.Diagnosed case of HIV/AIDS for HAART therapy and all cases of HIV/AIDS who are already on HAART therapy were included in this study.Descriptive statistical analysis was carried out by using frequencies and percentages.Results:Of 40 patients with HIV/AIDS,22(55.0%)were male and 18(45.0%)were female.The patients ranged in age from 8 to 60 years,with a mean age of 38±0.966 years.Among all age groups,the highest 19(47.5%)patients were in the 31-to 40-year age group.Most of the patients were migrant workers[22/40(55.0%)]with low socioeconomic status[32/40(80.0%)],and the most common transmission mode was heterosexual activity[36/40(90.0%)].Most of the patients[32/40(80.0%)]had mucocutaneous disorders,30/40(75.0%)had infective dermatoses,and 21/40(52.5%)had non-infective inflammatory dermatoses.Eight of forty(20.0%)patients presented with three or more skin disorders.The most common infective dermatoses were fungal infections[15/40(37.5%)],followed by viral infections[8/40(20.0%)],bacterial infections[4/40(10.0%)],and scabies[3/40(7.5%)].The most common non-infective dermatosis was generalized pruritus[6/40(15.0%)],followed by prurigo simplex[4/40(10.0%)],psoriasis[4/40(10.0%)],eczema[3/40(7.5%)],pruritic papular eruption[1/40(2.5%)],seborrheic dermatitis[1/40(2.5%)],urticaria[1/40(2.5%)],and xerosis[1/40(2.5%)].Patients treated with HAART had decreased rates of oral candidiasis and herpes simplex but increased rates of drug reactions[19/40(47.5%)].The most common drug eruption following HAART was a morbilliform rash[11/40(27.5%)],and the most common offending agent was nevirapine.The prevalence of mucocutaneous disorders was higher in patients with a CD4 cell count of<200 cells/mm3.Conclusions:A wide range of mucocutaneous disorders is observed in Bangladeshi patients with HIV/AIDS,and HAART has an impact on the spectrum of HIV/AIDS-associated mucocutaneous disorders.Skin and mucocutaneous disorders are seen at every stage of HIV/AIDS and are the initial presentation in most patients in Bangladesh.There is a need for increased attention to the diagnosis and treatment of skin diseases affecting the quality of life of patients withHIV/AIDS.