Anjana Dewanji | Indian Statistical Institute, Calcutta (original) (raw)

Papers by Anjana Dewanji

Ecological Research

In tropical urban areas, prone to invasions by multiple exotic species, there is a need for studi... more In tropical urban areas, prone to invasions by multiple exotic species, there is a need for studies to understand the precise nature of the relationship between native and exotic species. This observational study was conducted in a rapidly urbanizing Indian metropolis. It examined the native and exotic species separately as a function of richness and abundance of two focal exotic species, namely Mikania micrantha and Alternanthera philoxeroides, to find support for the hypothesis that an overall native-exotic relationship does not provide a true picture of the community composition. The richness of exotic species did not turn out to be a good predictor for the native-exotic richness relationship even after focal exotics were considered. However, when the richness components were analysed separately, Poisson log-linear models identified M. micrantha as the community-dominant, by virtue of its extensive cover. Neither soil resource availability nor the presence of other exotics had any influence on native species richness. The negative relationship of M. micrantha cover with other exotic species could be associated with a lower risk of native species loss in a community invaded by multiple exotic species. M. micrantha appeared to be a 'passenger' of habitat alteration, but was likely to become a 'driver' once it attains high covers due to its reported superior competitive abilities. Therefore, in tropical areas there is a need to prioritize management initiatives in order to identify the dominant invader species in a community and effectively manage the dominant-homogenized plots.

can use simple ultraviolet detection. Moreover, because our PCR products can be loaded directly o... more can use simple ultraviolet detection. Moreover, because our PCR products can be loaded directly onto the capillary, no preparative steps such as overnight digestion, precipitation, desalting, or extensive washing of the samples are required. This greatly speeds up the analysis and reduces both the labor and cost. Thus, our technique is ideally suited to semi-automation, and it can readily be applied to high-volume genotyping or screening programs.

Bangladesh Journal of Plant Taxonomy, 2007

Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds ... more Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds over a period of 39-month in order to gain an insight into their associations and infestation for implications in conservation and management. Species diversity was recorded in presence of two invasive species (Alternanthera philoxeroides (Martius) Griseb. and Lemna aequinoctialis Welwitsch). These species should be managed in

Plant Foods for Human Nutrition, 1993

The seasonal variation in the nutrient composition of Enhydrafluctuans and Marsilea quadrifolia, ... more The seasonal variation in the nutrient composition of Enhydrafluctuans and Marsilea quadrifolia, two edible semi-aquatic plants, was studied in order to promote their consumption as green leafy vegetables. Both plants had a high crude protein content throughout all harvesting seasons. Enhydrafluetuans had a low ash content and was a good source of/?-carotene (3.7 to 4.2mg/100g on a fresh weight basis). Marsilea quadr~lia exhibited wide fluctuations between seasons and was not very promising in nutrient composition when compared to other commonly used green leafy vegetables.

Plant Foods for Human Nutrition, 1997

In a study conducted on the extraction of protein from the leaves of 30 freshwater aquatic plants... more In a study conducted on the extraction of protein from the leaves of 30 freshwater aquatic plants, the highest standing crop fresh yield was found in Typha latifolia (2650 g/m2). The Bio-Medical Data Processing (BMDP) K-means clustering program with K = 2 showed that 11 of the 30 plants had a high protein nitrogen extractability as well as a high nitrogen content of the extracted protein. Among these, leaf protein from Allmania nodiflora had the highest content of crude protein (62.7%) and/~-carotene (782.4 vg/g). Leaf protein prepared from Hygrophila spinosa, Ottelia alismoides and Polygonum barbatum had low in-vitro digestibility. The levels of alkaloids and polyphenols were lower in the extracted protein compared to that present in the original leaf sample.

Acta hydrochimica et hydrobiologica, 2004

Management of Biological Invasions, 2012

An attempt was made to understand the potential of Alternanthera philoxeroides, alligator weed to... more An attempt was made to understand the potential of Alternanthera philoxeroides, alligator weed to adapt to diverse conditions present in pond ecosystems, through a correlative investigation of its natural growth pattern and peroxidase level. Eleven ponds were graded into two subjective categories: "A. philoxeroides Infestation" (High, Medium, Low) and "Level of Pollution" (High and Low), to test for difference in mean peroxidase concentration in A. philoxeroides populations. Significant changes in mean peroxidase concentration in A. philoxeroides were found in ponds categorized on the basis of level of pollution, indicating the adaptability of this plant to propagate under pollution stress. On the other hand, there was no significant change in mean peroxidase concentration for plants growing in ponds categorized on the basis of infestation showed that dense, vegetative proliferation caused no stress in A. philoxeroides. An efficient method of assaying peroxidase in A. philoxeroides, under field conditions, using the best suited leaf group (Tips, Tips + 1st leaf pair", 2nd leaf pair) was also explored. "Tips + 1st leaf pair" proved to be a better sample than mature leaves for estimation of peroxidase concentration in A. philoxeroides.

The Environmentalist, 2010

Field experiments on duckweeds, Lemna aequinoctialis, were carried out to determine the effect of... more Field experiments on duckweeds, Lemna aequinoctialis, were carried out to determine the effect of plant characteristics on water-quality variables in ponds. In view of their rapid growth rates and ability to cover water surfaces very quickly, such studies are necessary, especially in sub-tropical countries, in order to develop viable management strategies. Morphological parameters like leaf length, leaf width, and root length of individual plants along with cover percent of Lemna were studied in each pond along with important water-quality parameters. The plant parameters were related to the studied water-quality variables using regression analysis. Equations showed that changes in root length and cover, both easily measurable growth responses of duckweeds, could be used to reflect changes in two important water-quality variables like DO and phosphorus (both total and soluble reactive) concentrations in pond waters and hence be used effectively for routine monitoring. This study also gives an indication that ponds with low cover of duckweeds could possibly be more effective for prediction purposes.

International Journal of Environmental Studies, 2004

The ability of aquatic macrophytes to maintain water clarity was investigated in two tropical pon... more The ability of aquatic macrophytes to maintain water clarity was investigated in two tropical ponds [1999][2000][2001]. Low chlorophyll-a concentration (0.2-3.5 mg/m 3 ) was observed throughout the study period, which reflected the absence of any algal bloom. At a high coverage ( ≥ 90%), the ability of Vallisneria spiralis to maintain Secchi disk transparency ( > 2 m) extended to the deepest point (3.5-4.4 m) even at high Kjeldahl nitrogen (1.2-29.8 mg/l) and total phosphorus levels (0.2-1.2 mg/l).

Clinical Biochemistry, 2004

Objectives: To review and compare the biochemical, analytical, and clinical features of two relat... more Objectives: To review and compare the biochemical, analytical, and clinical features of two relatively new tests for assessing iron status and diagnosing iron disorders, namely, the serum transferrin receptor concentration (sTfR) and the erythrocyte zinc protoporphyrin/heme ratio (ZnPP/H). To consider the merits of each test for the diagnosis of iron disorders with emphasis on iron-deficient erythropoiesis, especially in the clinically important preanemia stage of iron depletion.

Bangladesh Journal of Plant Taxonomy, 2007

Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds ... more Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds over a period of 39-month in order to gain an insight into their associations and infestation for implications in conservation and management. Species diversity was recorded in presence of two invasive species (Alternanthera philoxeroides (Martius) Griseb. and Lemna aequinoctialis Welwitsch). These species should be managed in view of their beneficial uses. Nymphaea pubescens Willd, a threatened species, was recorded. Positive association of Nymphoides hydrophylla (Loureiro) O. Kuntze with Alternanthera philoxeroides and Vallisneria spiralis L. showed that spatially separated habitats are useful for conservation. Azolla pinnata R. Brown, an useful species and Rotala rotundifolia (F. Hamilton ex Roxburgh) Koehne, an uncommon species, were able to produce high coverage in their brief occurrence -important for their conservation. Similar feature as observed in Cladophora glomerata (L.) Kütz and Hydrodictyon reticulatum (L.) Lagerh. is useful for management of these species due to their negative impacts.

Aquatic Ecology, 2008

A study was conducted to ascertain monthly changes in biomass of the plant and nutrient content i... more A study was conducted to ascertain monthly changes in biomass of the plant and nutrient content in various organs of Nymphoides hydrophylla grown in a tropical pond during September 1999-August 2000 in relation to environmental factors. Biomass of N. hydrophylla ranged from 25 to 247 g dry weight m -2 . Among the various organs, leaf blade showed highest nitrogen (3.0-4.6%) and phosphorus content (0.9-2.4%). Comparative data of three Nymphoides species showed that N. peltata, the temperate species, had maximum potential of biomass production while long flowering period, year around growth, higher nitrogen content in various organs and presence of other associated flora were unique features of tropical species (N. hydrophylla and N. indica). Both water temperature and water level together appeared to be the best environmental variables that significantly explained the variability in biomass of N. hydrophylla.

Biological invasion is now a major threat to global biodiversity. As one of the worst invasive we... more Biological invasion is now a major threat to global biodiversity. As one of the worst invasive weeds in the world, research on various aspects of Mikania micrantha H.B.K. is increasing over the years. The plant was introduced in India after the Second World War and its profuse growth in Kerala and Assam over the years affected forests and tea plantations causing damage to the ecosystems and economy of the country. Since the 1980s it has started to spread and invade other Indian states and there is an urgent need to map and monitor the spread of this plant. This paper reviews the worldwide research trend over the years, the current status of the weed in India and reports the presence of this plant in an urban city like Kolkata in India.

Ecological Research

In tropical urban areas, prone to invasions by multiple exotic species, there is a need for studi... more In tropical urban areas, prone to invasions by multiple exotic species, there is a need for studies to understand the precise nature of the relationship between native and exotic species. This observational study was conducted in a rapidly urbanizing Indian metropolis. It examined the native and exotic species separately as a function of richness and abundance of two focal exotic species, namely Mikania micrantha and Alternanthera philoxeroides, to find support for the hypothesis that an overall native-exotic relationship does not provide a true picture of the community composition. The richness of exotic species did not turn out to be a good predictor for the native-exotic richness relationship even after focal exotics were considered. However, when the richness components were analysed separately, Poisson log-linear models identified M. micrantha as the community-dominant, by virtue of its extensive cover. Neither soil resource availability nor the presence of other exotics had any influence on native species richness. The negative relationship of M. micrantha cover with other exotic species could be associated with a lower risk of native species loss in a community invaded by multiple exotic species. M. micrantha appeared to be a 'passenger' of habitat alteration, but was likely to become a 'driver' once it attains high covers due to its reported superior competitive abilities. Therefore, in tropical areas there is a need to prioritize management initiatives in order to identify the dominant invader species in a community and effectively manage the dominant-homogenized plots.

can use simple ultraviolet detection. Moreover, because our PCR products can be loaded directly o... more can use simple ultraviolet detection. Moreover, because our PCR products can be loaded directly onto the capillary, no preparative steps such as overnight digestion, precipitation, desalting, or extensive washing of the samples are required. This greatly speeds up the analysis and reduces both the labor and cost. Thus, our technique is ideally suited to semi-automation, and it can readily be applied to high-volume genotyping or screening programs.

Bangladesh Journal of Plant Taxonomy, 2007

Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds ... more Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds over a period of 39-month in order to gain an insight into their associations and infestation for implications in conservation and management. Species diversity was recorded in presence of two invasive species (Alternanthera philoxeroides (Martius) Griseb. and Lemna aequinoctialis Welwitsch). These species should be managed in

Plant Foods for Human Nutrition, 1993

The seasonal variation in the nutrient composition of Enhydrafluctuans and Marsilea quadrifolia, ... more The seasonal variation in the nutrient composition of Enhydrafluctuans and Marsilea quadrifolia, two edible semi-aquatic plants, was studied in order to promote their consumption as green leafy vegetables. Both plants had a high crude protein content throughout all harvesting seasons. Enhydrafluetuans had a low ash content and was a good source of/?-carotene (3.7 to 4.2mg/100g on a fresh weight basis). Marsilea quadr~lia exhibited wide fluctuations between seasons and was not very promising in nutrient composition when compared to other commonly used green leafy vegetables.

Plant Foods for Human Nutrition, 1997

In a study conducted on the extraction of protein from the leaves of 30 freshwater aquatic plants... more In a study conducted on the extraction of protein from the leaves of 30 freshwater aquatic plants, the highest standing crop fresh yield was found in Typha latifolia (2650 g/m2). The Bio-Medical Data Processing (BMDP) K-means clustering program with K = 2 showed that 11 of the 30 plants had a high protein nitrogen extractability as well as a high nitrogen content of the extracted protein. Among these, leaf protein from Allmania nodiflora had the highest content of crude protein (62.7%) and/~-carotene (782.4 vg/g). Leaf protein prepared from Hygrophila spinosa, Ottelia alismoides and Polygonum barbatum had low in-vitro digestibility. The levels of alkaloids and polyphenols were lower in the extracted protein compared to that present in the original leaf sample.

Acta hydrochimica et hydrobiologica, 2004

Management of Biological Invasions, 2012

An attempt was made to understand the potential of Alternanthera philoxeroides, alligator weed to... more An attempt was made to understand the potential of Alternanthera philoxeroides, alligator weed to adapt to diverse conditions present in pond ecosystems, through a correlative investigation of its natural growth pattern and peroxidase level. Eleven ponds were graded into two subjective categories: "A. philoxeroides Infestation" (High, Medium, Low) and "Level of Pollution" (High and Low), to test for difference in mean peroxidase concentration in A. philoxeroides populations. Significant changes in mean peroxidase concentration in A. philoxeroides were found in ponds categorized on the basis of level of pollution, indicating the adaptability of this plant to propagate under pollution stress. On the other hand, there was no significant change in mean peroxidase concentration for plants growing in ponds categorized on the basis of infestation showed that dense, vegetative proliferation caused no stress in A. philoxeroides. An efficient method of assaying peroxidase in A. philoxeroides, under field conditions, using the best suited leaf group (Tips, Tips + 1st leaf pair", 2nd leaf pair) was also explored. "Tips + 1st leaf pair" proved to be a better sample than mature leaves for estimation of peroxidase concentration in A. philoxeroides.

The Environmentalist, 2010

Field experiments on duckweeds, Lemna aequinoctialis, were carried out to determine the effect of... more Field experiments on duckweeds, Lemna aequinoctialis, were carried out to determine the effect of plant characteristics on water-quality variables in ponds. In view of their rapid growth rates and ability to cover water surfaces very quickly, such studies are necessary, especially in sub-tropical countries, in order to develop viable management strategies. Morphological parameters like leaf length, leaf width, and root length of individual plants along with cover percent of Lemna were studied in each pond along with important water-quality parameters. The plant parameters were related to the studied water-quality variables using regression analysis. Equations showed that changes in root length and cover, both easily measurable growth responses of duckweeds, could be used to reflect changes in two important water-quality variables like DO and phosphorus (both total and soluble reactive) concentrations in pond waters and hence be used effectively for routine monitoring. This study also gives an indication that ponds with low cover of duckweeds could possibly be more effective for prediction purposes.

International Journal of Environmental Studies, 2004

The ability of aquatic macrophytes to maintain water clarity was investigated in two tropical pon... more The ability of aquatic macrophytes to maintain water clarity was investigated in two tropical ponds [1999][2000][2001]. Low chlorophyll-a concentration (0.2-3.5 mg/m 3 ) was observed throughout the study period, which reflected the absence of any algal bloom. At a high coverage ( ≥ 90%), the ability of Vallisneria spiralis to maintain Secchi disk transparency ( > 2 m) extended to the deepest point (3.5-4.4 m) even at high Kjeldahl nitrogen (1.2-29.8 mg/l) and total phosphorus levels (0.2-1.2 mg/l).

Clinical Biochemistry, 2004

Objectives: To review and compare the biochemical, analytical, and clinical features of two relat... more Objectives: To review and compare the biochemical, analytical, and clinical features of two relatively new tests for assessing iron status and diagnosing iron disorders, namely, the serum transferrin receptor concentration (sTfR) and the erythrocyte zinc protoporphyrin/heme ratio (ZnPP/H). To consider the merits of each test for the diagnosis of iron disorders with emphasis on iron-deficient erythropoiesis, especially in the clinically important preanemia stage of iron depletion.

Bangladesh Journal of Plant Taxonomy, 2007

Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds ... more Occurrence, coverage and chemical constituents of aquatic flora were studied in two Indian ponds over a period of 39-month in order to gain an insight into their associations and infestation for implications in conservation and management. Species diversity was recorded in presence of two invasive species (Alternanthera philoxeroides (Martius) Griseb. and Lemna aequinoctialis Welwitsch). These species should be managed in view of their beneficial uses. Nymphaea pubescens Willd, a threatened species, was recorded. Positive association of Nymphoides hydrophylla (Loureiro) O. Kuntze with Alternanthera philoxeroides and Vallisneria spiralis L. showed that spatially separated habitats are useful for conservation. Azolla pinnata R. Brown, an useful species and Rotala rotundifolia (F. Hamilton ex Roxburgh) Koehne, an uncommon species, were able to produce high coverage in their brief occurrence -important for their conservation. Similar feature as observed in Cladophora glomerata (L.) Kütz and Hydrodictyon reticulatum (L.) Lagerh. is useful for management of these species due to their negative impacts.

Aquatic Ecology, 2008

A study was conducted to ascertain monthly changes in biomass of the plant and nutrient content i... more A study was conducted to ascertain monthly changes in biomass of the plant and nutrient content in various organs of Nymphoides hydrophylla grown in a tropical pond during September 1999-August 2000 in relation to environmental factors. Biomass of N. hydrophylla ranged from 25 to 247 g dry weight m -2 . Among the various organs, leaf blade showed highest nitrogen (3.0-4.6%) and phosphorus content (0.9-2.4%). Comparative data of three Nymphoides species showed that N. peltata, the temperate species, had maximum potential of biomass production while long flowering period, year around growth, higher nitrogen content in various organs and presence of other associated flora were unique features of tropical species (N. hydrophylla and N. indica). Both water temperature and water level together appeared to be the best environmental variables that significantly explained the variability in biomass of N. hydrophylla.

Biological invasion is now a major threat to global biodiversity. As one of the worst invasive we... more Biological invasion is now a major threat to global biodiversity. As one of the worst invasive weeds in the world, research on various aspects of Mikania micrantha H.B.K. is increasing over the years. The plant was introduced in India after the Second World War and its profuse growth in Kerala and Assam over the years affected forests and tea plantations causing damage to the ecosystems and economy of the country. Since the 1980s it has started to spread and invade other Indian states and there is an urgent need to map and monitor the spread of this plant. This paper reviews the worldwide research trend over the years, the current status of the weed in India and reports the presence of this plant in an urban city like Kolkata in India.