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1.
A key to the management of hillstreams in relation to Fish Species Richness (FSR) and Shannon and Weaver Diversity Index (H) (Shannon and Weaver, 1949. The Mathematical Theory of Communications. Urbana, University of Illinois Press, IL, USA) using a multitude of factors such as altitude, water source, bed gradient, dominant channel materials and habitat type has been proposed on the basis of 10 study sites, belonging to three north Indian rivers namely; Ghaggar, Yamuna and Ganga. The selected streams are located between the altitudes ranging from 380 to 1524m. It has been observed that high altitude streams having steep gradient, boulder dominated substrate with rapids as the main habitat type had lower FSR (3–4) and H (0.55–0.99) as compared to hillstreams located in the lower altitudes having gentle gradient, cobble dominated substrate with pools, riffles, runs, rapids and cascades as the main habitats and have high FSR (6–14) and H (1.67–2.35). Types – A, B and F hillstreams were encountered when the hillstreams are classified after Rosgen (Applied River Morphology, Wildland Hydrology, Co, USA).  相似文献   

2.
《Journal of Asia》2021,24(4):1116-1121
Understanding population genetics, genetic diversity and the migration pattern of ecologically important species is crucial for effective conservation plans. We studied mitochondrial cytochrome c oxidase subunit-I (COI) gene variation in painted lady butterfly (Vanessa cardui) from different altitudinal gradients of Uttarakhand (Western Himalayas), India. We sequenced COI) gene of 91 samples and 22 COI sequences retrieved from GenBank as representatives of different localities for comparative analysis. We observed a total of 16 haplotypes, of which seven haplotypes were observed in Uttarakhand with intra-species sequence divergence ranges from 0.001 to 0.009. Haplotype (Hd) and nucleotide diversity (π) were comparatively low and averaging 0.635 and 0.002, respectively. The neutrality test, mismatch distribution graph and observed pattern of diversity indices (Hd and π) revealed population expansion. It was further confirmed by the Median Joining Network, which exhibited a star-like topology from the core haplotype, while the Bayesian phylogenetic tree displayed a mixing of haplotypes from different localities to an identical clade. Haplotype organization in the Bayesian tree and Median Joining Network was not clustered as per their topographical affinity, indicating incomplete lineage sorting and late species population development or colonization in the novel area.  相似文献   

3.
在长时间尺度上研究环境变化条件下的种群动态,有助于确定不同物种如何对新的生物和非生物条件做出反应。采纳类似的采集方法在相同的地点,分别于1961-1962年和2003-2004年在西喜马拉雅地区对果蝇种类进行了两次野外调查,对两次调查获得的种类的相对丰富度和优势度指数进行了比较。最近50年的气象数据显示西喜马拉雅平均气温(Tave)发生了显著变化,对该地区的果蝇种类组成及分布界限产生了影响。本研究发现在低海拔的地带Drosophila nepalensis及其他一些冷适应种类的数量明显下降;而Drosophila ananassae及其他一些暖适应种类则进入了低海拔和中海拔地带。D. nepalensis的丰富度与所调查地点的平均气温负相关(r = -0.93±0.03),而对于D. ananassaez则是相反趋势(r=0.90±0.05)。据此认为长期(42年)的气候变化已对西喜马拉雅地区的果蝇种类的分布格局产生了影响。  相似文献   

4.
The present investigation on fertility and mortality differential among Kinnaura of the Himalayan highland is based on data collected from 160 post-menopausal women belonging to the middle and high altitude region of Kinnaur district of Himachal Pradesh (Indian Himalayas). Selection potential based on differential fertility and mortality was computed for middle-and high-altitude women. Irrespective of the methodology, the total index of selection was found to be highest among middle-altitude women (0.386) as compared with high-altitude (0.370) women, whereas for the total population it is estimated to be 0.384. It was found that the Kinnaura of the Himalayan highland showing moderate index of total selection and relative contribution of the mortality component (Im) to the index of total selection is higher than the corresponding fertility component (If). The analysis of embryonic and post-natal mortality components shows that the post-natal mortality components are higher in comparison with the embryonic mortality components among highlanders and needs special intervention and health care. The present findings are compared with other Indian tribes as well as non-tribes of the Himalayan region and other parts of the country. It reveals that this index among Kinnaura is moderate than the other population groups; among the Himalayan population, the highest was reported for Galong (It = 1.07) of Arunachal, whereas the lowest was reported from Ahom (It = 0.218) of Manipur. The correlation and regression analysis between total index of selection (It) and fertility (If) and mortality (Im) components for pooled data of populations of the Indian Himalayan states show that If and Im account for 21.6 and 29.1% variability, respectively. In Crow's total index of selection (It) along with strong association, which is significant at the 1% level, this indicates that mortality plays a greater role in natural selection in comparison with fertility among populations of the Indian Himalayas.  相似文献   

5.
Himalayan soils undergo dramatic temporal changes in their microclimatic properties. The soil habitats in the high altitude cold habitats of Himalayas are little explored with respect to bacterial diversity and metabolic potentials of the bacterial species. Soil habitat in Western Himalayas is dominated by the genera of Pseudomonas, Arthrobacter, Bacillus, and Flavobacterium. Strains were found to be diverse in their metabolic potentials to utilize different carbon sources by growing them on media containing 114 different sole carbon sources. Bacillus sp. STL9 was supported by the lowest number (12.3%) of the carbon sources while growth was observed in 73.7% of the carbon sources tested for the Pseudomonas sp. SPS2. Carbohydrates appeared to be preferred carbon sources for these Himalayan isolates followed by amino acids and proteins. These microbes also produced various extra-cellular hydrolytic enzymes having biotechnological potentials, lipase being the one secreted by most strains (85.7%) followed by β-galactosidase (42.8%). Antibiotic resistance profiling for 85 different antibiotics has also been described.  相似文献   

6.
The wheatbelt region of Western Australia has been extensively cleared of indigenous vegetation for agriculture and is now severely affected by dryland salinity. Wetlands that were once freshwater are now saline and others are under threat, as are the animals and plants that inhabit them. Rising groundwater is also affecting the many naturally saline playas. To provide a framework for setting conservation priorities in this region a biological survey was undertaken, including sampling of aquatic invertebrates at 230 wetlands. In this paper, we have used data from the survey to summarise occurrence of species in relation to salinity. Total species richness at a wetland showed no response to salinity below 4.1 g l−1 and then declined dramatically as salinity increased. When halophilic species were excluded from consideration, species richness was found to decline from 2.6 g l−1. These patterns are compared to previous studies of richness-salinity relationships. There is some evidence that the freshwater invertebrate fauna of the wheatbelt may be comparatively salt tolerant, with 46% of freshwater species collected at salinities above 3 g l−1 and 17% above 10 g l−1, though these proportions differed between various invertebrate groups. While this tolerance will provide a buffer against the effects of mild salinisation, many species are at risk of regional extinction as salinisation becomes more widespread.  相似文献   

7.
As an adaptive mechanism, hypocotyl dormancy delays emergence of functional leaf until favorable season of growth in Podophyllum hexandrum, an endangered medicinal plant of the western Himalayas. However, upon exposure of the freshly germinated seedlings to favorable temperature (25°C), functional leaves emerged within 20 days. Therefore, we examined regulation mechanisms of growth and development of this alpine plant by temperature under laboratory conditions. The seedlings were exposed to (1) 25°C (temperature prevailing at the time of maximum vegetative growth), (2) 4°C (mean temperature at the onset of winter in its natural habitat), and (3) 10°C (an intermediate temperature). Slackened growth at 4°C was followed by senescence of aerial parts and quiescence of roots and predetermined leaf primordia. Rapid development of leaf primordia at 25°C was associated with increased starch hydrolysis. This was evident from higher α-amylase activity and reducing sugars. These parameters decreased on sudden exposure to 4°C. In contrast, the roots (perennating organs) showed a slight increase (1.36-fold) in α-amylase activity. Growth and development in seedlings growing at 10°C (temperature less adverse than 4°C) were comparatively faster. The content of reducing sugars and α-amylase activity were also higher in all the seedling parts at 10°C as compared to 4°C. This indicated larger requirements for sugar by the seedlings at 10°C. Irrespective of temperature, maximum changes in nitrate and nitrate reductase occurred during the initial 10 days, i.e., when the readily available form of sugars (reducing sugar) was highest. This indicated that a temperature-dependent availability of carbon, but not temperature itself, was an important regulator of uptake and reduction of nitrogen. IHBT Publication number 508a.  相似文献   

8.
This paper argues that the altitude-oriented mixed mountain agriculture model in which mountain dwellers move to higher altitudes in summer and lower ones in winter does not fit the empirical situation in many areas of the Himalayas where north-south or latitudinally differentiated habitat and production zones play important and, in some instances, central roles.  相似文献   

9.
The distributions of Assamese macaques (Macaca assamensis) and rhesus macaques (M. mulatta) in Bhutan have been only partially documented. In order to investigate the distribution patterns of these species, we conducted field observation and genetic assessment with mitochondrial DNA (mtDNA) typing of macaques in the Inner Himalayas of Bhutan. There were 24 sightings of macaque groups, and all were visually identified as Assamese macaques. No groups of rhesus macaques were sighted in this survey area, in contrast with the survey results in the Nepalese Himalayas. Molecular phylogenetic analysis revealed that the Bhutan macaques are closer in proximity to their counterparts in the Indo-Chinese region (Thailand and Laos) than to rhesus macaques in China, Laos and India. However, clustering results suggested the marked differentiation of the macaques in Bhutan from the Assamese macaques in Indo-China. We tentatively conclude that the macaques of the Inner Himalayan regions in Bhutan are Assamese macaques and that they appear to be of a lineage distinct from Assamese macaques in the Indo-Chinese region (subspecies M. a. assamensis). The degree of mtDNA diversity suggests that the Assamese macaques in Bhutan are of a more ancient ancestry than M. a. assamensis, thereby supporting the speciation hypothesis of the expansion of a sinica-group of macaques from South Asia to Southeast and then to East Asia (Fooden; Fieldiana Zool 45:1–44, 1988). Assignment of Assamese macaques in Bhutan to M. a. pelops is premature due to the lack of molecular data and recent taxonomic controversy. The mtDNA diversity of Assamese macaques was greater than that of rhesus macaques, suggesting the earlier speciation of Assamese macaques. The significance of the ecogeographic segregation model of macaque distribution is discussed in relation to the evolutionary range expansion into the Himalayan regions in South Asia.  相似文献   

10.
Wild relatives (WR) of temperate fruits belonging to genera viz., Malus, Prunus, Pyrus, Vitis, Rubus, Fragaria and others showed a wide range of diversity thereby possibility of utilizing large numbers of desirable genes/traits particularly the resistance to biotic and abiotic stresses which is generally lacking in their cultivated allies. About 55 WR of 23 temperate fruits, occurring in WH, including those naturalized, are discussed. Wild forms of crops such as Asiatic pear, apricot, Japanese plum, peach, walnut and pomegranate, blackberry, black and redcurrant existing in WH are also narrated. Wild relatives, their area of distribution, important traits, utilization potential and possible strategies for their effective conservation and utilization have been discussed.  相似文献   

11.
The Himalayan mountain range is one of the most species-rich areas in the world, harboring about 8% of the world's bird species. In this study, we compare the relative importance of immigration versus in situ speciation to the build-up of the Himalayan avifauna, by evaluating the biogeographic history of the Phylloscopus/Seicercus warblers, a speciose clade that is well represented in Himalayan forests. We use a comprehensive, multigene phylogeny in conjunction with dispersal-vicariance analysis to discern patterns of speciation and dispersal within this clade. The results indicate that virtually no speciation has occurred within the Himalayas. Instead, several speciation events are attributed to dispersal into the Himalayas followed by vicariance between the Himalayas and China/Southeast Asia. Most, perhaps all, of these events appear to be pre-Pleistocene. The apparent lack of speciation within the Himalayas stands in contrast to the mountain-driven Pleistocene speciation suggested for the Andes and the East African mountains.  相似文献   

12.
The ratios of stable isotopes 18O/16O and 13C/12C, in sagittal otolith carbonate from two tropical demersal teleosts, red emperor Lutjanus sebae and Rankin cod Epinephelis multinotatus , from several locations in northern Western Australia, differed between sites. On a broad scale, fish from the four locations, Shark Bay, Ningaloo, Pilbara, and Broome had stable isotope values that were sufficiently different to indicate separate stocks, and it is appropriate to manage these populations of the two species independently in these areas. On a smaller scale, there may be limited mixing of these species between the Pilbara trawl fishery and the trap and line fisheries operating out of Onslow and Broome. Values of stable oxygen isotopes were strongly related to sea surface temperature, although there were some sites in shallow water where low values of stable oxygen isotopes indicated that fish were living in warm water. The use of stable oxygen and carbon isotope values is a valuable, cost effective method of determining the degree of mixing of fish stocks.  相似文献   

13.
Nature management in coastal areas of Western Europe   总被引:1,自引:0,他引:1  
V. Westhoff 《Plant Ecology》1985,62(1-3):523-532
The general environmental characteristics of West European coastal dunes and those of salt marshes are outlined. It is pointed out that the dynamical character of the dune system with its interaction between plants and sand in building and degeneration phases has been known for a much longer period of time than generally believed.As to the salt marshes the special significance is discussed of ungrazed marshes; the majority of the marshes having been under a grazing regime for a long time is elucidated.The distinction between internal management is mentioned, i.e. the measures taken to maintain or improve the qualities of an area, versus external management, i.e. the measures to prevent or counteract negative influences from outside the area.Nomenclature follows Heukels & Van Ooststroom (1977).  相似文献   

14.
Aim To study (1) the large-scale distribution patterns of freshwater fishes in the Western Ghats of India; (2) the endemism and uniqueness of the fishes in various zones; and (3) the threat status of fishes by categorizing them under low risk (LR), vulnerable (VU), endangered (EN) and critically endangered (CR). Location The Western Ghats of India. Methods The scientific literature describing the freshwater fishes of the Western Ghats was reviewed. Data describing the lists of the species were extracted and complied. The species accumulation curve was plotted using Michaelis–Menten-like equation. The Western Ghats was divided into six zones and similarity of the species was calculated using Jacquard's index. Results Literature to date records 288 species belonging to 12 orders, 41 families and 109 genera, of which 118 species are endemic and 51 are unique. However, the species accumulation curve shows that there might be 345 species in this region, indicating that 16% species have not been recorded to date. An analysis of the distribution pattern of fishes in the Western Ghats suggests that the southern region is more diverse than the northern and central regions. The southern region shows high endemism and high uniqueness while the northern region shows high endemism but less uniqueness. The similarity index between the zones indicates that as the distance between the zones increases similarity decreases. The status of 105 of 288 species was not known due to data deficiency but among the remaining 183 species, 58 species were categorized as LR, 41 as VU, 54 as EN, 24 as CR while the remaining six species were introduced. Conclusions The distribution patterns of fishes in the Western Ghats are discussed in accordance with the geography of Western Ghats, its climatic conditions and ‘Satpura Hypothesis’. The threat status of fishes found in Western Ghats suggests that at least 41% of fish fauna is threatened by either being VU, EN or CR. Implication of potent conservation measures is necessary to conserve the fish fauna of Western Ghats.  相似文献   

15.
Ethnic people of the Himalayan regions of India, Nepal, Bhutan and China consume a variety of indigenous fermented milk products made from cows milk as well as yaks milk. These lesser-known ethnic fermented foods are dahi, mohi, chhurpi, somar, philu and shyow. The population of lactic acid bacteria (LAB) ranged from 10(7) to 10(8) cfu/g in these Himalayan milk products. A total of 128 isolates of LAB were isolated from 58 samples of ethnic fermented milk products collected from different places of India, Nepal and Bhutan. Based on phenotypic characterization including API sugar test, the dominant lactic acid bacteria were identified as Lactobacillus bifermentans, Lactobacillus paracasei subsp. pseudoplantarum, Lactobacillus kefir, Lactobacillus hilgardii, Lactobacillus alimentarius, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris and Enterococcus faecium. LAB produced a wide spectrum of enzymes and showed high galactosidase, leucine-arylamidase and phosphatase activities. They showed antagonistic properties against selected Gram-negative bacteria. None of the strains produced bacteriocin and biogenic amines under the test conditions used. Most strains of LAB coagulated skim milk with a moderate drop in pH. Some strains of LAB showed a high degree of hydrophobicity, suggesting these strains may have useful adhesive potential. This paper is the first report on functional lactic acid bacterial composition in some lesser-known ethnic fermented milk products of the Himalayas.  相似文献   

16.
Taxol content in the bark of Himalayan Yew in relation to tree age and sex   总被引:8,自引:0,他引:8  
Taxol content in the bark of Taxus baccata trees growing in a homogenous (uniform) environment at Jageshwar, District Almora in Central Himalaya has been quantified. The average taxol concentration in the bark of sampled trees was 0.0558+/-0.008% (of dry wt.) and was about 64% higher for male plants (averaged across tree age) in comparison to female trees. Maximum taxol content was recorded in the bark samples collected from trees of >110 yrs age. ANOVA indicates a significant difference in the taxol content of bark from trees of different ages, however, differences were not significant between sexes. Taxol was quantified by HPLC using a standard curve prepared with authentic taxol; the identification of bark taxol was confirmed by UV and mass spectrometry. The total taxol content of the bark of Taxus trees across an age series was found to range between 0.064 to 8.032 g/tree, and a tree of about 100 yrs age can yield 5.74 kg dry bark.  相似文献   

17.
Two monotypic genera of coccosteoid eubrachythoracid arthrodires are described from the Upper Devonian Gogo Formation of Western Australia as Compagopiscis gen. nov. and Gogopiscis gen. nov. They are most closely related to Torosteus Gardiner & Miles, also from the Gogo Formation, and all three are placed in the family Plourdosteidae Vezina, 1990; Compagopiscis and Gogopiscis are jointly the sister-group of Torosteus.  相似文献   

18.
Rare fishes of Himalayan waters of Nepal   总被引:1,自引:0,他引:1  
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19.
Pratap Singh  Trevor D. Price 《Ibis》2015,157(3):511-527
Aspects of birdsong complexity, such as the number of distinct notes in a song, commonly increase along latitudinal gradients, a pattern for which at least 10 explanations have been suggested. In two Himalayan warblers, songs are more complex in the northwest than in the southeast. In Grey‐hooded Warbler Phylloscopus xanthoschistos, high complexity results from increased note diversity within song types, sung across a higher bandwidth. In Blyth's Leaf Warbler Phylloscopus reguloides, high complexity is a consequence of increased variation between song types. The hypothesis with strongest support is that songs evolved to be more complex in species‐poor, demonstrably less noisy environments. We consider geographical variation to be an outcome of sexual selection favouring complexity across environments, where detection of the signal varies. Sexual selection favouring complexity may be resolved in different ways, because complexity has multiple features (repertoire size, song switching, etc.). We argue this has led to the great diversity in song that we have documented among five Phylloscopus species.  相似文献   

20.
M. A. Khan 《Hydrobiologia》1986,135(3):233-242
L. Naranbagh (alt. 1587 m) is a polymictic, shallow marl lake in the flood-plain valley of Kashmir, India. Macrofloral affinities resemble Potamogeton Type of Forsberg (1965) with alkaline waters, not rich in phosphorus. CaCO3 precipitation coupled with decline in Ca2+ and alkalinity values are characteristic of the lake. Fluctuations in Mg2+, Na+, K+, and Cl were relatively conservative. The levels of PO inf4 sup3– -P and NO inf3 sup– -N indicate moderate fertility of the lake water.Persistence of a summer-autumn planktonic algal pulse is related to favourable irradiance, high water temperatures, and increased photosynthetic efficiency values. The most striking seasonality in photosynthetic rates (m–2 h–1) between winter minimum (3 mg Cassim) and summer maximum (75.4 mg Cassim) is determined by mainly climatic changes. Energy flow gave annual phytoplankton production of 51.95 × 102 KJ m–2 for the ecosystem.The nutrient levels and productivity rates suggest mesotrophic status of L. Naranbagh in classic oligoeutrophic classification of lake types.  相似文献   

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