Diatoms as indicators of river quality in the Nepalese Middle Hills with consideration of the effects of habitat-specific sampling

1. Using a replicated survey design at the catchment scale, we compared the composition and diversity of diatom communities in three stream groups in the Middle Hills of Nepal: semi-natural reference (Arun Valley), enriched by agricultural runoff (Likhu Khola) and grossly polluted by sewage (Kathmandu Valley). We sampled riffles at all sites; in the Kathmandu Valley and Likhu Khola we also sampled diatoms in pools and on vegetation.
2. Species richness and diversity H' were significantly higher in agricultural streams than in either organically polluted streams or references. Community composition, as shown by principal components analysis, varied significantly between all three stream types due to differences in the abundances of species characteristic of organic enrichment (Kathmandu Valley), moderate enrichment (Likhu Khola) or undisturbed hillstreams (Arun Valley).
3. Few species varied in relative abundance between pools, riffles and vegetation so that variations in community composition and diversity were stronger between stream groups than between habitats. Samples from any one habitat produced only 75.7% (± 8.6 SD) of the species from three habitats, so that surveys aimed at recording biodiversity may need more comprehensive habitat coverage than surveys for biomonitoring.
4. We conclude that diatom communities can indicate different sources of pollution in Nepalese streams, and advocate further studies to develop this indicator potential over a wider area of the Himalaya. Comparisons between replicate groups of streams selected a priori helped to clarify effects which were sometimes obscured by other survey designs.     

Diatoms as indicators of river quality in the Nepalese Middle Hills with consideration of the effects of habitat-specific sampling

1. Using a replicated survey design at the catchment scale, we compared the composition and diversity of diatom communities in three stream groups in the Middle Hills of Nepal: semi-natural reference (Arun Valley), enriched by agricultural runoff (Likhu Khola) and grossly polluted by sewage (Kathmandu Valley). We sampled riffles at all sites; in the Kathmandu Valley and Likhu Khola we also sampled diatoms in pools and on vegetation.
2. Species richness and diversity H' were significantly higher in agricultural streams than in either organically polluted streams or references. Community composition, as shown by principal components analysis, varied significantly between all three stream types due to differences in the abundances of species characteristic of organic enrichment (Kathmandu Valley), moderate enrichment (Likhu Khola) or undisturbed hillstreams (Arun Valley).
3. Few species varied in relative abundance between pools, riffles and vegetation so that variations in community composition and diversity were stronger between stream groups than between habitats. Samples from any one habitat produced only 75.7% (± 8.6 SD) of the species from three habitats, so that surveys aimed at recording biodiversity may need more comprehensive habitat coverage than surveys for biomonitoring.
4. We conclude that diatom communities can indicate different sources of pollution in Nepalese streams, and advocate further studies to develop this indicator potential over a wider area of the Himalaya. Comparisons between replicate groups of streams selected a priori helped to clarify effects which were sometimes obscured by other survey designs.     

Diatoms on herbarium macrophytes as indicators for water quality

To describe the reference situation for water quality in the eutrophicated broad area De Nieuwkoopse Plassen (Holland), attached diatoms from aquatic macrophytes, collected between 1934 and 1958 have been used. Recent samples for comparison were taken in 1989.The diatoms do not indicate significant changes in salinity. Eutrophication has reduced the number of rare species and increased the abundance of meso- to hyper-eutraphentic species, particularly Fragilaria berolinensis. Reduction of total phosphorus to concentrations below 0.02 mg 1^–1 might be sufficient to restore the diatom assemblages of the 1930s.     

Are diatoms good integrators of temporal variability in stream water quality?

1. Although diatoms have been used for many decades for river monitoring around the world, studies showing evidence that diatoms integrate temporal variability in water chemistry are scarce. 2. The purpose of this study was to evaluate the response of the Eastern Canadian Diatom Index (IDEC: Indice Diatomées de l’Est du Canada) with respect to temporal water chemistry variability using three different spatio‐temporal data sets. 3. Along a large phosphorus gradient, the IDEC was highly correlated with averaged water chemistry data. Along within‐stream phosphorus gradients, the IDEC integrated phosphorus over various periods of time, depending on the trophic status of the site studied (Boyer, Nicolet or Ste. Anne river) and variability in nutrient concentration. 4. In the Ste. Anne River, where nutrient concentrations were low and generally stable, an input of phosphorus induced a rapid change in diatom community structure and IDEC value within the following week. In the mesotrophic Nicolet River, the observed integration period was approximately 2 weeks. Diatom communities in the eutrophic Boyer River appeared to be adapted to frequent and significant fluctuations in nutrient concentrations. In this system, the IDEC therefore showed a slower response to short term fluctuations and integrated nutrient concentrations over a period of 5 weeks. 5. Our results suggest that the integration period varies as a function of trophic status and nutrient concentration variability in the streams. Oligotrophic streams are more sensitive to nutrient variations and their diatom communities are directly altered by nutrient increase, while diatom communities of eutrophic rivers are less sensitive to nutrient fluctuations and major variations take a longer time to be integrated into index values. 6. The longer integration period in the eutrophic environment may be attributed to the complexity of the diatom community. The results from this study showed that the diversity and evenness of the communities increased with trophic status.     

Diatoms as indicators of water quality in some English urban lakes

SUMMARY. 1. The paper describes diatom communities from a series of linked urban lakes in relation to water chemistry and uses multivariate statistical techniques to show how indicator groups can he defined.
2. Diatoms are classified into ecological groups using two-way species indicator analysis (TWINSPAN). Each ecological group is associated with a specific range of water-quality conditions. The headwater stream environments are differentiated from the lake habitats at level 1. At level 2 of TWINSPAN. the sampling sites are grouped into five ecological groups, according to their water chemistry and irrespective of the time of year.
3. Detrended correspondence analysis (DCA) and principal components analysis (PCA) provide two statistically independent methods of assessing the environmental gradients along which the ecological groups are distributed. The most important physico-chemical parameters are total hardness, specific conductance and pH, followed by phosphates and nitrates.
4. Ecological groups I-V correspond to an environmental gradient ranging from the forested headwaters, which are acidic, of low specific conductance, total hardness and nutrient content, through the urban lakes, which are alkaline and of relatively high total hardness, specific conductance and nutrient content.
5. Twelve site groups are identified at level 3 of TWINSPAN, each of which corresponds to a narrower range of water-quality conditions within the ecological groupings. A specific diatom assemblage is associated with each site group.
6. Benthic diatoms form an integral part of the diatom assemblages found in the water column and this is identified as a topic for further study.     

Effect of Urbanization and Seasonality in Bird Communities of Kathmandu Valley,Nepal

Kathmandu Valley, Nepal is undergoing rapid urbanization but its effects on the bird communities have not been reported till date. Kathmandu Valley was categorized into urban, sub-urban and rural to study the impact of urbanization in bird communities. By mobilizing volunteers, we monitored 24 transects each with one km long in summer and winter seasons of 2016. A total of 13,749 individuals of birds belonging to 102 species were recorded. Species richness and diversity of all birds declined from rural to urban areas and showed significant variation along urban–rural gradients. Insectivore was the most species-rich guild while nectarivore the least. The richness of insectivore, frugivore and carnivore guilds showed significant variations along the urban–rural gradients and higher preference towards the rural areas. Similarly, species richness of all birds and richness of insectivore and carnivore guilds showed significant seasonal variation and were higher in the winter season. Our results indicate that richness, diversity and feeding guilds of birds show different response towards the urbanization gradients and seasons. Sub-urban areas can function as bird refugia, however, habitat enrichments (like increasing green spaces, setting up new parks and gardens, plantation of native fruiting trees etc.) are utmost necessary to support the bird communities in urban areas of Kathmandu Valley.     

Diatoms as indicators: The influences of experimental nitrogen enrichment on diatom assemblages in sub-Arctic streams

Indices using diatoms are widely used to assess water quality, but are usually constructed from field correlations and not tested through rigorous experimentation. We tested experimentally the performance of the Sørensen and the Shannon indices, and the trophic diatom index (TDI). Nitrogen was naturally limiting in the eight remote sub-Arctic streams used and we measured the effects of experimental nitrogen enrichment on diatom assemblages. Diatom densities increased significantly in the enriched reaches but there was no significant difference in invertebrate density between control and treatment reaches. Grazing effects were thus controlled for. Diversity within streams (Shannon index) was significantly reduced by nutrient addition but the Sørensen index did not change. The trophic diatom index (TDI), which is presumed to reflect nutrient concentration, was not influenced by nutrient addition and generally the values were low in both control and treatment reaches. Densities of the diatom genera Achnanthes and Gomphonema increased significantly with enrichment while those of Nitzschia and Fragilaria decreased significantly. Less abundant diatom species, which collectively constituted around 40% in relative abundance in the control reaches, were around 15–18% in treatment reaches. Growth forms were altered by the nutrients. Diatoms attached by mucilage pads were more abundant in treated reaches compared with control reaches. Motile diatoms became scarcer. The size of diatom species was unaffected by nutrient enrichment. This study showed that it is important to test experimentally indices that are developed for particular habitats before using them elsewhere.     

Diarrhea,respiratory infections,protozoan gastrointestinal parasites,and child growth in Kathmandu,Nepal

The differential impact of diarrhea, respiratory infections, and protozoan parasitism on growth is investigated among children under five years of age living in periurban Kathmandu, Nepal. The children's parents are all carpet-making workers who live in an environment with crowded living conditions, poor sanitation, and contaminated water. Anthropometric data, both cross-sectional and longitudinal, were collected over a 9-month period. Morbidity data were gathered from maternal reports, and a subsample of children's stools were examined for gastrointestinal parasites. In a comparison of current growth status and growth velocity for children with and without diarrhea and respiratory infections, it is found that body weight is most affected by infections, particularly for children under 24 months of age. For a subsample of children whose stools were tested for parasites, there is a statistically significant association between stunting (low height-for-age) and the presence of a protozoan gastrointestinal parasite. It is concluded that although growth faltering is associated with diarrhea and respiratory infections, the impact of these infections is of less importance for long-term linear growth retardation than is infection by protozoan gastrointestinal parasites.     

Algal epilithon and water quality of a stream receiving oil refinery effluent

Changes in epilithic algal communities colonizing introduced substrata were determined in a stream polluted with oil refinery effluent at Digboi (Assam, India). The number of algal taxa was reduced but the growth of blue-green algae, particularly two species ofOscillatoria, was encouraged. Epilithic biomass (as chlorophylla) also declined at polluted stations. The algal community of the upstream station was markedly different from the community occurring just after the confluence of effluent; however, the differences were gradually reduced downstream, indicating improvement in water quality. Of the various criteria tested for possible relationships with the level of pollutants, species richness, Shannon diversity and biomass showed significant relationships. The study demonstrates the usefulness of algal criteria for monitoring oil pollution in running waters.     

Proximate determinants of fertility in the Kathmandu Valley, Nepal: an anthropological case study

The analytical model of Bongaarts and Potter is employed to compare the proximate determinants of fertility among 3 populations in Nepal's Kathmandu valley. 3 sub-groups are studied: high caste (Brahmin and Chetri) urban residents, high caste urban fringe residents, and low caste untouchables (Sarki). Both survey and anthropological methods are employed. According to the analytical model, the transition in fertility follows 4 phases. The changes in fertility levels from Phase 1 to Phase 4 generally indicate that the transition from natural to controlled fertility is characterized by declines in the proportions of women married and the duration of postpartum infecundability, and a substantial increase in the prevalence and effectiveness of contraceptive practices. The results of this study show that Nepal as a whole is entrenched in Phase 1 of the fertility transition. However, data from the 3 populations reported here clearly indicate that each has begun to experience a demographic transition to different degrees. The Sarkis in this study fall between Phases 2 and 3, as indicated by the total fertility rate (TFR). The rural high castes most closely approximate a population in Phase 3, while urban high castes included in this study are approaching Phase 4. Each of the 3 populations is characterized by a decline in the proportion of women married when compared to all of Nepal. It is also apparent that the relative use-effectiveness of contraceptive methods currently employed is high. Gains in the reduction of fertility, then, will have to be made from increasing and retaining the number of acceptors and in reducing the desired family size of those at reproductive risk.     

Diatoms as quantitative indicators of pH and water temperature in subarctic Fennoscandian lakes

Weighted averaging (WA) regression and calibrationbased optima and tolerances of lakewater pH andtemperature are presented for diatoms in ecologicallysensitive, subarctic Fennoscandian lakes. The studysites are mostly small, simple, oligotrophic,low-conductivity lakes with a pH range from 5.0 to7.7 and a temperature range (after data screening)from 9.3 to 15.0 °C. Experiments with inverse andclassical deshrinking, with or without tolerancedownweighting, were used to identify the bestcalibration functions. The model estimates wereadjusted by jackknifing procedures. WA by inversedeshrinking and with tolerance downweighting performedbest for pH prediction, whereas simple WA wasmarginally superior for predicting water temperature.The established pH model is accurate to within±0.39 H units, and the temperature model towithin ±0.88 degrees Celcius. Fifteen diatom taxawere identified as potential indicator species for pHand three for temperature.     

Phytoplankton and zooplankton as indicators of water quality in Discovery Bay,Jamaica

Several investigations exist which use planktonic communities as indicators of water quality in Jamaican and Caribbean Bays, however, few are conducted before there are obvious effects of eutrophication. Therefore, most of our ‘baseline’ data are for bays already severely affected by pollution. This study was conducted to assess water quality in Discovery Bay, Jamaica, before there were severe signs of eutrophication. The bay was monitored over a 12-month period (October 1995–September 1996) using 10 stations. Physicochemical data indicated a well mixed upper 5 m of water column, below which discontinuities in temperature/salinity profiles indicated the influence of colder, more saline waters associated with deep offshore currents. Physicochemical variables were within the range for oligotrophic systems with a tendency towards mesotrophic in localized areas close to the shoreline. Signs of anthropogenic stress were associated with the eastern, southwestern and western sections of the bay. Of the over 120 species of phytoplankton found in the waters of Discovery Bay, most were neritic/oceanic and diatoms dominated while 11 were found to be potentially harmful species. While these harmful species occurred at all stations they occurred most frequently at stations on the eastern side of the bay. About 107 zooplankton species were identified, 52 of which were copepods. The species also represented a mix of neritic and oceanic taxa and mean abundances for the area ranged from 1077 m⁻³ at the mouth of the bay to 3794 m⁻³ close to the south shore (station 6). Generally stations closest to shore had greater zooplankton abundances than centrally located bay stations and stations close to oceanic influence. Acartia tonsa and Lucifer faxoni showed greatest densities at shoreline areas of the bay while Oithona plumifera, Undinula vulgaris and Temora stylifera were important at stations closest to oceanic influences. These species were thus considered as indicators of these different areas within the bay. From physicochemical data and the planktonic assemblage, Discovery Bay cannot be considered polluted, it is still more accurately classified as generally pristine with mesotrophic zones in the eastern and southeastern sections of the bay. These data therefore provide a real baseline of conditions for similar tropical coastal embayments.     

七项河流附着硅藻指数在东江的适用性评估

综合运用因子分析、聚类分析、箱型图分析等统计方法评估了河流附着硅藻生物指数(Biological Diatom Index,IBD)、硅藻营养化指数(Trophic Diatom Index,TDI)、斯雷德切克指数(Sládecˇek’s Index,SLA)、特定污染敏感指数(Specific Polluosensitivity Index,IPS)、硅藻属指数(Generic Diatom Index,IDG)、戴斯指数(Descy Index,DESCY)和欧盟硅藻指数(European Economic Community Index,CEE)在东江流域河流水质评价中的适用性。结果显示:SLA与IPS,CEE显著相关(P<0.05),CEE与TDI不相关,其余指标间均极显著相关(P<0.01)。SLA与13项水质理化指标均无相关性,TDI与含氯度(Cl)显著负相关,CEE与溶解氧(DO)、电导率(Cond.)、总氮(TN)显著正相关(P<0.05),其余指标与氨氮(NH4-N)、pH不存在线性相关,与五日生化需氧量(BOD5)、高锰酸盐指数(CODKMnO4)、亚硝氮(NO2-N)、硝氮(NO3-N),总磷(TP)具极显著相关性(P<0.01)。13项水质理化指标中主成分负荷贡献大于50%的八项理化参数DO、BOD5、CODKMnO4、TN、NO3-N、NO2-N、TP和SiO2将试验区水质分为四组。IPS、IBD、IDG和CEE与水质物化分类一致性较好。IPS、IBD、IDG和CEE的逐步判别分析(引入P=0.20,剔除P=0.25)显示IPS和CEE都只选出了NO2-N,分类判别的正确率分别为55.6%和48.1%;IBD引入了NO2-N,CODKMnO4和DO 3个解释变量,判别正确率74.1%;IDG引入BOD5和NO3-N两个变量,分组正确率63.0%。硅藻群落聚类显示,IBD和IDG在水质物化分类的箱型图中呈现出明显合理的趋势。以上研究表明IBD和IDG硅藻指数最适合用于东江河流水质生物监测与评价。     

Evaluation of coliforms as indicators of water quality in India

P.W. RAMTEKE, J.W. BHATTACHARJEE, S.P. PATHAK AND N. KALRA. 1992. The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed.     

Plant endemism in the Nepal Himalayas and phytogeographical implications

Nepal is located in the central part of the greater Himalayan range with a unique series of mountain chains formed by recent mountain building geological events. As one of the youngest mountains in the world it contributes to diversity of plants and also provided barriers to and corridors through which plants migrated during the ice ages. The higher altitudinal variation with the high mountains, deep river valleys and lowland plains combine with the effects of the summer monsoon and dry winter result with an extraordinary diversity of ecosystems including flora and fauna in a relatively small land area. The existing checklists for Nepal record some 6000 species of flowering plants and about 530 ferns. However, the botanical experts estimate that numbers may go up to 7000 when the poorly known remote regions are fully explored. The information on plant endemism in Nepal Himalaya is not adequately known as Nepal is still struggling to complete long awaited Flora of Nepal project. Endemic species are confined to specific areas and are the first to be affected by land use and other global changes. We sought to explore the spatial distribution of endemic plant species in Nepal in relation to the consequences associated with climatic and geologic changes over time in the region with the help of published literature. It was found that the endemism showed marked spatial variation between open moist habitat and dry inner valleys, the former with higher endemism. The updated records showed 312 flowering plant species to be endemic to Nepal with higher endemism around the elevation of 3800e4200 m at sea level. The recent human population explosion, intensified deforestation, habitat fragmentation and modern day environmental changes are posing greater threats to endemic plant in Nepal. The conservation status and threats to these peculiar species are unknown. Nevertheless, environmental degradation and high poverty rates create a potent mix of threats to biodiversity in this landscape.     

Evaluation of coliforms as indicators of water quality in India.

The total and thermotolerant coliform counts in rural drinking water derived from ground water, piped supplies and surface water are reported for a number of areas in India. To evaluate these counts as indicators of recent faecal contamination the total coliforms and thermotolerant coliforms isolated have been identified. Thermotolerant Escherichia coli formed 11.7% of the total coliforms and 75.1% of the thermotolerant coliforms. Citrobacter sp. (20.4%) and Klebsiella sp. (50.9%) were the other common total coliforms isolated and, among the thermotolerant coliforms, Klebsiella sp. (16.4%) was the only other organism frequently encountered. The total coliform counts were significantly correlated with water temperature. The applicability in tropical areas of standards developed for temperate climates is discussed.