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11 documents found tagged ecology [X]
  • Title
    New locality records of the ‘Dancing Girl’ of Mizoram, a rare zinger species
    Type
    Journal Article
    Description
    Mantisia spathulata (Roxb.) Schult. belonging to the family Zingiberaceae is a rare ornamental Zingiber distributed from eastern Himalaya to Myanmar. In India, this species is confined to very few localities of northeastern India. A new location for the species was discovered at Kolasib, Mizoram. The species was recorded growing at an altitude of 662m. A thorough ecological sampling was done for the population. Density of flowering individuals and non-flowering young individuals were estimated. The species has never been recorded at this altitude previously and, as per record, no ecological work has been done earlier. The average density of Mantisia spathulata within its growing patch is 18(±2) individuals per m2. A total of 120 juvenile individuals (without flowers) were recorded from a 1×1 m2 plot; indicating a very good regeneration of the species within the patch where it is growing.
    Attribution
    Aparajita De & Demsai Reang, Journal of Threatened Taxa, Vol 8, No 5 (2016); pp. 8841–8843 http://dx.doi.org/10.11609/jott.2051.8.5.8841-8843
  • Title
    Mangrove sediment core analysis of foraminiferal assemblages - a study at two sites along the western coast of India
    Type
    Journal Article
    Description
    Mangroves are an unique habitat and are largely influenced by sea level changes and wave energy. Foraminifera (Protista) preserved in mangrove sediments provide an excellent proxy for deducing past conditions. One meter deep mangrove core samples at two sites on the western coast of India were collected. The foraminiferal assemblages at various depths showed significant changes in the abundance and diversity down the cores. A total of 59 species belonging to 32 genera, 24 families and five suborders were identified from the cores of these two sites. The cores showed an abundance of genus Rotalidium particularly the species Rotalidium annectans. Other species identified include Ammonia, Elphidium, Nonion, Spiroloculina, Quinqueloculina, Globigerinoides, etc. The pH, organic matter and CaCO3 also showed variations down the cores. There was a lack of correlation between sediment characteristics and the abundance of foraminifera in the cores. The low diversity and differences in distribution of foraminifera compared to surface intertidal samples may be due to intense post depositional changes or anthropogenic disturbances. The mangrove ecology thus appears disturbed by various factors.
    Attribution
    Vidya P., Patil R.K. (2014). Journal of Threatened Taxa 2(6) pp. 5485-5491; doi:10.11609/JoTT.o3653.5485-91
  • Title
    Ecology and conservation of threatened plants in Tapkeshwari Hill ranges in the Kachchh Island, Gujarat, India
    Type
    Journal Article
    Description
    The survey was conducted in Tapkeshwari Hill Range (THR) areas, wherever threatened plant species were said to exist, based on secondary information in literature. Thirteen plant species categorized as ‘Threatened’ by the World Conservation Monitoring centre (WCMC 1994) and also listed under various threat categories in the Red Data Book of Indian Plants (Nayar & Sastry 1988) were surveyed in the THR. All the RET plants reported from the study area occupied eight major habitat types. Thorn mixed forests harbored the highest number of individuals (560) of all RET plants, followed by open scrubs (345 individuals), Acacia senegal forests (328) and thorn mixed scrubs (293). Field observations showed that except Helichrysum cutchicum, all the other RET plant species were reported with very low seedlings and regeneration ratio. This paper discusses the status, distribution and threats faced and the conservation implications at border regions of some of the threatened plants of the arid Kachchh district.
    Attribution
    Joshi P.N., Joshi E.B., Jain B.K. (2012). Journal of Threatened Taxa 2(4) pp. 2390-2397; doi:10.11609/JoTT.o2410.2390-7
  • Title
    Zooplankton diversity of Loktak Lake, Manipur, India
    Type
    Journal Article
    Description
    Zooplankton communities of Loktak Lake showed rich and speciose biocoenosis (162 and 142 species), high monthly richness (91 plus or minus 13 and 80 plus or minus 10 species) and by higher similarities (51.1-82.0 and 51.8-78.3 %) and peak richness during winter and autumn over two years of study. Zooplankton (267 plus or minus 41 n/l) formed a significant quantitative component (56.0 plus or minus 6.3 %) of net plankton and showed annual peak abundance during winter. Rotifera and Cladocera are dominant quantitative groups while Copepoda and Rhizopoda are sub-dominant groups. We observed significant annual and monthly variations of zooplankton richness and abundance. This study showed limited influence of individual abiotic factors on zooplankton, with richness showing a significant inverse correlation with water hardness and chloride, and abundance inversely correlated with nitrate. Multiple regressions indicated higher cumulative effects of 15 abiotic factors on richness and abundance. Our results exhibited no definite periodicity of richness and abundance of zooplankton and their constituent groups during two annual cycles. Zooplankton is characterized by highest species diversity (4.172 plus or minus 0.237), higher evenness and lower dominance.
    Attribution
    Sharma B.K., Sharma S. (2011). Journal of Threatened Taxa 5(3) pp. 1745-1755; doi:10.11609/JoTT.o2457.1745-55
  • Title
    Some aspects of the ecology of the Indian Giant Squirrel Ratufa indica (Erxleben, 1777) in the tropical forests of Mudumalai Wildlife Sanctuary, southern India and their conservation implications
    Type
    Journal Article
    Description
    The Indian Giant Squirrel Ratufa indica, an endemic species to India, is widely distributed from the evergreen to moist and dry deciduous forests of Western and Eastern Ghats and the central Indian hills. We studied its population distribution, activity, feeding, ranging and nesting behaviour across three major habitats in the tropical forests of Mudumalai Wildlife Sanctuary, southern India, during 1998-2000 to manage the species effectively. Extensive survey of the three major habitats—tropical moist, dry deciduous and dry thorn—in the sanctuary shows that its distribution is continuous in moist and dry deciduous forests with good canopy contiguity and patchy along riverine areas in dry thorn and dry deciduous forests with sparse trees and broken canopy. Density estimates using 55 direct sightings from 199 km line transects show a mean of 2.9 (plus or minus 0.313) squirrels/km2. Daylight activity and feeding patterns assessed through 24,098 minutes of focal sampling reveal that animals feed and rest equal amounts of time. The diet constitutes seeds, bark, petioles, leaves and fruits from 25 plants, with Tectona grandis as the principal food source (41%). Its home range size varied from 0.8-1.7 ha with a mean of 1.3ha. Nesting characteristics assessed through 83 nests surveyed along 54km transects showed that the squirrel uses 15 of the 33 tree species found, with higher preference to Schleichera oleosa and Mangifera indica. Nest trees are significantly larger in height, gbh and canopy contiguity than nearest non-nest trees, which are attributed to better protection and escape from predators. Maintenance of diverse natural habitats and reduction in anthropogenic pressure are measures suggested for the conservation of giant squirrel populations in the study area.
    Attribution
    Baskaran N., Venkatesan S., Mani J., Srivastava S.K., Desai A.A. (2011). Journal of Threatened Taxa 7(3) pp. 1899-1908; doi:10.11609/JoTT.o2593.1899-908
  • Title
    Key to the larval stages of common Odonata of Hindu Kush Himalaya, with short notes on habitats and ecology
    Type
    Journal Article
    Description
    The order Odonata is one of the most widely studied groups among insects from the oriental region. They colonize in both stagnant and running water bodies of wide water quality. Hitherto, the existing literature on the Odonata contained numerous publications with coloured figures of adults, helpful for identification. Identification key with figures on larval stages, using their coloration as distinguishing characters are largely missing. The current work attempts to provide an identification key to aquatic larvae of the most common families of Zygoptera, Anisoptera and Anisozygoptera with colour illustrations. The specimens were collected from Nepal and India (northern part). Each family is represented by several examples to demonstrate the range of morphological variability. This key helps determination of aquatic larvae Odonata up to family level without enormous efforts in field and laboratory.
    Attribution
    Nesemann H., Shah R.D.T., Shah D.N. (2011). Journal of Threatened Taxa 9(3) pp. 2045-2060; doi:10.11609/JoTT.o2759.2045-60
  • Title
    Rotifer communities of Deepor Beel, Assam, India: richness, abundance and ecology
    Type
    Journal Article
    Description
    Plankton samples collected from two sampling stations of Deepor Beel (a Ramsar site in Assam, northeastern India) between November 2002 and October 2003, reveal 110 and 100 species of Rotifera, exhibit monthly richness ranging between 43-65 (56 plus or minus 6) and 38-60 (52 plus or minus 7) species and record 48.9-88.1 and 53.1-89.7% community similarities respectively. Rotifera (231 plus or minus 60 and 198 plus or minus 70 n/l) comprise between 48.7 plus or minus 6.1 and 42.6 plus or minus 4.1% of zooplankton abundance at station I and II respectively, and follow trimodal annual patterns with peaks during winter. Brachionidae (90 plus or minus 43, 79 plus or minus 39 n/l) > Lecanidae (45 plus or minus 13, 29 plus or minus 9 n/l) form important quantitative components of Rotifera while Asplanchnidae > Synchaetidae > Trochosphaeridae are other notable families. Lecane > Brachionus > Keratella > Asplanchna > Platyias contribute notably to temporal variations of the rotifers. Asplanchna priodonta, Keratella cochlearis, Platyias quadricornis, Lecane leontina, Polyarthra vulgaris, Keratella tropica and Brachionus falcatus are important species. Analysis of variance comparisons indicate significant temporal variations in richness and abundance of Rotifera between stations and months. The rotifer communities exhibit higher species diversity, higher evenness, lower dominance and lack of quantitative dominance of any individual species. The present results show no definite periodicity of richness and abundance of this group, families or species. Individual abiotic factors register limited influence on richness and abundance while multiple regression exhibits higher cumulative influence of ten abiotic factors on these parameters at both sampling stations.
    Attribution
    Sharma B.K. (2010). Journal of Threatened Taxa 8(2) pp. 1077-1086; doi:10.11609/JoTT.o2411.1077-86
  • Title
    Phytoplankton diversity of two floodplain lakes (pats) of Manipur, northeastern India
    Type
    Journal Article
    Description
    Phytoplankton communities of Utra and Waithou pats (floodplain lakes) of Manipur, studied during November 2002 - October 2004, revealed 62 and 61 species, and indicated monthly richness between 27-45 (38 � plus or minus 4) and 32-46 (39 � plus or minus 4) species respectively with distinct qualitative importance of Chlorophyta (29 � plus or minus 4 and 28 � plus or minus 3 species). Phytoplankton (154 � plus or minus 31 n/l and 164 � plus or minus 34 n/l) comprised between 43.8 � plus or minus 3.0 % and 41.5 � plus or minus 3.0 % of net plankton abundance respectively of these two lakes. Chlorophyta (115 � plus or minus 23 n/l and 113 � plus or minus 21 n/l), the dominant quantitative component (74.4 � plus or minus 4.1% and 67.5 � plus or minus 4.8%), indicated importance of the demids. Bacillariophyta (33 � plus or minus 9 n/l and 37 � plus or minus 12 n/l) formed sub-dominant group, and Dinophyta > Euglenophyta > Chrysophyta showed very low densities. Various abiotic factors registered relatively limited influence on richness and abundance of phytoplankton as well as on abundance of individual groups in Utra Pat than in Waithou Pat. Multiple regression depicted higher cumulative influence of fifteen abiotic factors on the stated biotic parameters in these pats. Both richness and abundance of Phytoplankton recorded significant monthly variations, showed insignificant temporal variations between two lakes and followed indefinite annual patterns in each pat. Phytoplankton communities of the sampled pats are characterized by higher species diversity, higher evenness and lower dominance.
    Attribution
    Sharma B.K. (2010). Journal of Threatened Taxa 11(2) pp. 1273-1281; doi:10.11609/JoTT.o2427.1273-81
  • Title
    Microcrustacea (Crustacea: Branchiopoda) of Deepor Beel, Assam, India: richness, abundance and ecology
    Type
    Journal Article
    Description
    Plankton samples collected from two sampling stations of Deepor Beel, an important floodplain lake of Assam and a Ramsar site of India, revealed 51 species of Microcrustacea and showed qualitative dominance of Cladocera (45 species). Microcrustacea comprised a significant quantitative component (45.6 � plus or minus 5.8 and 50.8 � plus or minus 4.5 %) of zooplankton and exhibited bimodal and trimodal annual patterns with peaks during winter. Cladocera > Copepoda are important quantitative groups. ANOVA registered significant variation in species richness and abundance of Microcrustacea over time and between stations. Richness and abundance were inversely correlated with water temperature and rainfall, and positively correlated with specific conductivity and dissolved oxygen. Multiple regression registered significantly higher cumulative effects of ten abiotic factors on these two parameters. Our results are characterized by higher species diversity, higher evenness and lower dominance of Microcrustacea and show lack of distinct quantitative importance of individual species.
    Attribution
    Sharma B.K., Sharma S. (2009). Journal of Threatened Taxa 8(1) pp. 411-418; doi:10.11609/JoTT.o2169.411-8
  • Title
    Diversity of microcrustacea (Crustacea: Branchiopoda) of Loktak Lake, a Ramsar site, Manipur, India
    Type
    Journal Article
    Description
    Microcrustacea of Loktak Lake (collected during Nov. 2002-Oct. 2004) reveal 57 species and show qualitative dominance of Cladocera (51 species). They indicate monthly richness ranging between 33�plus or minus 6 and 32� plus or minus 6 species, record 51.7-82.3 and 53.6-90.0% community similarities during two years respectively, and follow trimodal annual patterns with peaks during winter. The microcrustaceans (112� plus or minus 17 and 124� plus or minus 13 n/l) form an important quantitative component (45.7� plus or minus 4.9 and 43.3� plus or minus 3.7 %) of zooplankton and show broadly trimodal annual patterns with peak abundance during winter. Cladocera > Copepoda mainly contribute to their quantitative variations. ANOVA registers significant monthly variations of microcrustacea richness and significant annual and monthly variations of their abundance. Richness is positively correlated with dissolved oxygen and is negatively correlated with rainfall, hardness, chloride and total dissolved solids while abundance is negatively correlated with pH only. Multiple regressions indicate higher cumulative effect of 15 abiotic factors on richness and abundance. Our results indicate no definite periodicity of richness and abundance of microcrustacea or their constituent groups during two annual cycles and are characterized by their higher species diversity, higher evenness and lower dominance.
    Attribution
    Sharma B.K., Sharma S. (2009). Journal of Threatened Taxa 11(1) pp. 541-548; doi:10.11609/JoTT.o2231.541-8
  • Title
    Study on the torrential catfish Amblyceps apangi Nath & Dey 1989 (Teleostei: Amblycipitidae) from Wokha district, Nagaland
    Type
    Journal Article
    Description
    Streams of Wokha district, Nagaland were surveyed (2005-2006) to document the torrential fish fauna. Amblyceps apangi Nath & Dey (1989) was collected from seven of the 12 streams surveyed, and found to be abundant in those streams. Detailed description of the study area, habitat characteristics of the streams, habitat ecology of the fish and a morphological study (based on 20 males and 20 females), is discussed.
    Attribution
    Humtsoe N., Bordoloi S. (2009). Journal of Threatened Taxa 2(1) pp. 109-113; doi:10.11609/JoTT.o1815.109-13