Spatial Distribution of Benthic Macroinvertebrate Fauna in Mountain Streams of Uttarakhand, India (original) (raw)
Related papers
This is the pioneering attempt to study the spatial patterns in structure of lotic ecosystems that form the Ganga River system in the Himalaya. The diversity of source (glacier-fed [GF], snow-fed [SN] and springfed [SF]) and stream-size (both interrelated) across the altitudinal panorama, create numerous habitats that contribute to structural diversity. The spatial patterns in richness, density and taxonomic composition and distribution of benthic diatoms are less affected by source compared with macro-invertebrates but shows strong influence on the distribution of fish fauna that are poikiliotherms, because a glacier-fed river carries ice-cold water (usually <20 • C) in contrast to normal waters in spring-fed system (22 • C near snowline, 32 • C in foothills). The abundance patterns of biota of lower organisation grade (diatoms, macroinvertebrates) do not differ sharply even across distant river basins as they are more influenced by proximate factors; thus the sub-basins of the Alaknanda resemble more by virtue of one basin and there is notable resemblance between distant SF Bemunda (lower Ganga basin) and SF Gomti (East Rāmgangā basin) and even the farthest Yamuna and Rāmgangā. Fish are more sensitive to temperature and current velocities that are related to altitude and hence longitudinal rather than the spatial gradients in the mountains. The lotic ecosystem of Doon Valley harbour rich and diverse diatom flora, macroinvertebrate fauna and ichthyofauna. The examination of trophic, saprobic and ecological status shows that organic pollution, degradation and anthropogenic eutrophication are non-existent in the Lesser Himalayan rivers and streams, but the fragile Doon Valley is under severe anthropogenic stress. This and habitats fragmented by hydropower projects in the major rivers has threatened the iconic game fish Himalayan mahseer in the Ganga.
Freshwater Biology, 1994
1. Hydrobiological changes were assessed along an altirudinal transect of eighteen to twenty-three tributaries from 600 to 3750m in two adjacent river systems in east-central Nepal. The transect incorporated catchments under terraced agriculture at the lowest altitudes in the Likhu Khola, through streams in forest, alpine scrub and tundra at higher altitudes in Langtang.2. Diatoms, bryophytes, macroinvertebrates and fish all showed pronounced altitudinal changes in assemblage composition as shown by TWINSPAN and DECORANA. A few taxa were restricted to streams at high altitude, but many more occurred only at lower altitudes where taxon richness increased substantially despite catchment disturbance by terraced agriculture.3. Diatoms characteristic of lower altitude streams were mostly motile, epipelic or episammic Navicula and Nitzschia spp., which occur typically at greater electrolyte and nutrient concentrations. Those characteristic of higher and steeper sites included attached Fragilaria spp. and prostrate Achnanthes spp., tolerant of turbulent flow.4. Cover by bryophytes varied within catchment type; high altitude springs supported dense mats, unlike streams fed by ice and glaciers. Taxa confined to low altitudes included those characteristic of humid subtropical conditions.5. Invertebrate families occurring only at lower altitudes included a range of burrowers and pool dwellers. Numerically, filter feeding Hydropsychidae and Simuliidae dominated streams in terraced and forested catchments, whereas grazing baetid mayflies dominated higher altitude streams in scrub and tundra.6. The combined density and biomass of at least six fish species in the Likhu Khola were 23–250 (per 100m−2), and 86–1282 g wet mass (per 100 m−2), respectively. No fish were found in Langtang streams, probably because torrential headwaters prevented colonization.7. Our data confirm that altitudinal transitions in stream biota are pronounced in the Himalaya of Nepal, but are likely to reflect a wide array of potential influences.
Structure of Benthic Macroinvertebrate Communities in the Rivers of Western Himalaya, Nepal
Geosciences
According to River Continuum Concept (RCC), channel morphology, including sediment loads and channel width, river habitat, flow regimes and water quality, differs from the tributary to the downstream river’s mainstem, allowing shifts in faunal composition from dominance of shredders to collectors downstream, respectively. Tributaries are responsible for contributing organic carbons, nutrients and water. However, such knowledge is still limited in the monsoon-dominated river systems of the Himalaya. The study was conducted in the river’s mainstem and tributaries of the Karnali River Basin, which are glacier and spring-fed river systems, respectively, in the western Himalaya, Nepal. A total of 38 river stretches in the river’s mainstem and tributaries were sampled during post-monsoon and pre-monsoon seasons in the years 2018 and 2019. Water quality parameters, such as pH, temperature, electrical conductivity, total dissolved solids, dissolved oxygen, alkalinity and hardness, and the b...
Hydrobiologia, 2010
We developed a system for the assessment of ecological condition for rivers in the lower mountains and lowlands of the Hindu Kush-Himalayan region (Pakistan, India, Nepal, Bhutan, and Bangladesh). We used benthic invertebrates collected from 198 rivers, located in five different ecoregions and covering degradation gradients; samples were taken twice (pre-monsoon and post-monsoon) applying a multi-habitat sampling procedure. Out of 38 environmental parameters, we constructed complex principal component analysis (PCA) gradients, separately for the stressors organic pollution, eutrophication, floodplain land use, and hydromorphological degradation. Correlation analysis between invertebrate metrics and environmental parameters revealed those biological metrics that are most responsive to river deterioration. Redundant metrics were deleted, and the most robust metrics were selected. The range of the index values under reference conditions was defined, and a five-class river quality system was generated.
Our Nature
Large-scale distributional pattern for the benthic macro-invertebrate fauna was determined in the glacier fed Himalayan and Trans-Himalayan rivers and streams of India at the elevation range of 2000-3000 m asl. In Trans-Himalaya the family Heptageniidae (Ephemeroptera) alone (Chandra and Bhaga) or in combination with Chironomidae (Diptera) in similar proportions (Chenab) or Diptera alone (Miyar) dominated the assemblages. Its influence seems to extend to Rupin drainage in the Himalaya where Chironomidae alone dominated the assemblages. Except for this Himalayan river. Various families of Trichoptera attained highest abundance in other rivers of the Himalaya. Thus, Leptoceridae in combination with Limnephilidae (Alaknanada at Tapovan) and Heptageniidae and Baetidae (Alaknanada at Mana) is the only instance of similarity in abundant taxa by virtue of same river. The Mandakini was partially similar to Alaknanda by virtue of abundant Limnephilidae. The Bhagirathi was characterized by abundance of Philopotamidae. Thus, assemblages exhibit greater variability in the Himalayan rivers than Trans-Himalayan rivers and are hence entirely different, as also evident from the cluster analysis. This present hypothesis is not applicable to explain the macro-invertebrate assemblages in Himalayan and Trans-Himalayan region.
Macroinvertebrate communities in streams in the Himalaya, Nepal
Freshwater Biology, 1993
1 Macroinvertebrates were sampled in the riffles of fifty-eight streams from three regions of the Himalaya (Anapurna, Langtang and Everest) in Nepal. A semi-quantitative method with identification to family level was used to describe communities on-site.2 Stream physicochemistry was assessed and the community structure of macroinvertebrates was related to chemistry, physiography (substratum composition, altitude and size), geographical location and the dominant land use in each catchment (terraced agriculture, forest or scrub). Community data were analysed by ordination (DECORANA) and classification (TWINSPAN).3 The concentration of cations in stream water decreased significantly with altitude. Chemistry also differed between regions; sites from Anapurna had a higher pH and conductivity than those in the other two areas.4 Communities were dominated by aquatic insect larvae, with Ephemeroptera, in particular the Baetidae, most numerous across sites.5 There were, nevertheless, differences in community structure between sites, which were related closely to stream physicochemistry. Ordination scores were strongly correlated with altitude, magnesium concentration and substratum composition. Classification was also linked to altitude and chemistry, differentiating high-altitude sites with low silica concentrations from others. Sites from the Anapurna and Everest regions, with their contrasting chemistry, were also separated.6 Community structure was also related to land use: streams draining catchments dominated by terraced agriculture had different communities from those in scrub or forest. This result was confounded, however, by the strong relationship between land use, altitude and chemistry; sites in terracing were at lower altitude, had higher concentrations of silica and a higher proportion of fine sediments than those in the other land-use types.7 Overall, our data indicate that natural features of the relief and geology in the Himalaya create strong gradients in their invertebrate faunas, but that activities of man may have an effect on stream structure and ecology through catchment management. Macroinvertebrates were sampled in the riffles of fifty-eight streams from three regions of the Himalaya (Anapurna, Langtang and Everest) in Nepal. A semi-quantitative method with identification to family level was used to describe communities on-site. Stream physicochemistry was assessed and the community structure of macroinvertebrates was related to chemistry, physiography (substratum composition, altitude and size), geographical location and the dominant land use in each catchment (terraced agriculture, forest or scrub). Community data were analysed by ordination (DECORANA) and classification (TWINSPAN). The concentration of cations in stream water decreased significantly with altitude. Chemistry also differed between regions; sites from Anapurna had a higher pH and conductivity than those in the other two areas. Communities were dominated by aquatic insect larvae, with Ephemeroptera, in particular the Baetidae, most numerous across sites. There were, nevertheless, differences in community structure between sites, which were related closely to stream physicochemistry. Ordination scores were strongly correlated with altitude, magnesium concentration and substratum composition. Classification was also linked to altitude and chemistry, differentiating high-altitude sites with low silica concentrations from others. Sites from the Anapurna and Everest regions, with their contrasting chemistry, were also separated. Community structure was also related to land use: streams draining catchments dominated by terraced agriculture had different communities from those in scrub or forest. This result was confounded, however, by the strong relationship between land use, altitude and chemistry; sites in terracing were at lower altitude, had higher concentrations of silica and a higher proportion of fine sediments than those in the other land-use types. Overall, our data indicate that natural features of the relief and geology in the Himalaya create strong gradients in their invertebrate faunas, but that activities of man may have an effect on stream structure and ecology through catchment management.
Springer, 2019
Increasing advancement in development activities in the Indian Himalayan region in tandem with changing climate is influencing the ecological patterns of rivers. Thus, the present study investigates the effect of various degrees of anthropogenic stresses and possible implication of thermal dynamics of river water on the macroinvertebrate community in the Mandakini River, which flows in the vicinity of Kedarnath Wildlife Sanctuary of Chamoli district, Uttarakhand. The main objective was to study the community structure of macroinvertebrates in the Mandakini River and to calculate the effect of anthropogenic stresses on the macroinvertebrate community, particularly on Ephemeroptera, Plecoptera, and Trichoptera. The study was carried out in 10 spatially located sampling stations, and the frequency of sampling was divided into pre-and post-monsoon season (May and November 2017). Based on the degree of anthropogenic stresses, sampling locations were divided into least (Sonprayag), medium (Ukhimath), and high disturbed (Rudraprayag) sites. A total of 3257 individuals belonging to 7 orders and 21 families were found in both the sampling season. Diptera and Trichoptera were dominant orders in both the seasons, whereas Baetidae (Ephemeroptera), Hydropsychidae, Leptoceridae (Trichoptera) and Chironomidae (Diptera) were dominant families. Shannon diversity index varies from 2.048 to 2.25 in the least disturbed site (Sonprayag), 0.186-2.446 in medium disturbance (Ukhimath), and 1.362-2.271 in the highly disturbed site (Rudraprayag) in both the sampling season. Quanti-fication of the EPT index shows a negative trend with an increase in anthropogenic stress, and it was least in Rudraprayag as compared to the other two sites. Result of one-way ANOVA shows a significant difference in diversity between pre-and post-monsoon season (p < 0.05). Analyzing the research gaps, it is recommended to have long-term ecological monitoring of high altitude and glacier-fed rivers and streams to obtain robust information regarding the dynamics of the riverine ecosystem in Garhwal Himalayas.
Aquatic Ecosystem Health & Management, 2017
This study reveals the relationship of biotic assemblages to their environments in the Central Highland Ecoregion rivers (Ken, Paisuni and Tons). Such knowledge will enhance our predictive abilities in the ecological studies and resource management in the concerned region. Rivers of an ecoregion are expected to harbour similar flora, fauna, and communities. This hypothesis was examined by tracking the spatial variation in richness, density, and taxonomic composition of benthic diatom and macroinvertebrate assemblages in three Plateau rivers whose course lay within 3°N latitude. Taxonomic richness and density decreased with the reduction of substrate size from the headwaters to the lowlands. Cluster and ordination analyses indicate prevalence of intrabasin rather than interbasin gradients of abundance. In both assemblages, the most abundant taxon is rarely similar longitudinally or across the river sections in the ecoregion. Hence, proximate factors govern the assemblages rather than...
The present study was carried out to investigate the comparative seasonal distribution and relative abundance of fish fauna of streams Bachan Gad of river Alaknanda and Kakda Gad of river Mandakini of Mid-himalayan Ganga river System. Total length of the Bachan Gad is 14.5 km from origin to the confluence at main river Alaknanda with an altitudinal variation from 605.94 to 1418.23m (a.s.1), whereas, total length of the Kakda Gad is 15.5 km. from origin to confluence at main river Mandakini with altitudinal variation from 984.50 to 1993.70 m (a.s.1). Total 23 species from Bachan Gad and 20 fish species were identified from Kakda Gad. The differences in the availability of fish-fauna were directly related to the nature of the profile and slope of tributaries; which affects the migration and breeding grounds of the fishes inhabited in the main river Alaknanda and Mandakini of Ganga river system. Variation in the availability of fishes has been recorded from different sites of the stream. In streams and rivers the changes take place along their length is directly related to the eco-physico-chemical nature (water depth, current, substratum etc). All these factors which change along the length of streams are also the factors which control the distribution of the various sections of the biotic fauna and flora.