Flowering Calendar of the Macrophytes of Keibul Lamjao National Park, Loktak Lake, Manipur, India

Keibul Lamjao National Park (KLNP), Loktak lake Manipur, north-east India which is one of the 25 Ramsar sites of international importance and the biggest fresh water Lake in India. Macrophytes of the floating Phumdi mat environment of KLNP play an important role in the aquatic environment. An investigation was planned during the period of about three years from March, 2010 to December 2012, to study the diversity pattern of habitats of macrophytes available in six study sites of KLNP viz., 1.Kumbi, 2.Khordak, 3.Keibul, 4.Toya, 5. Nongmaikhong and 6. Sargam. All total 85 dominant plant species were recorded. Maximum plant species (49) was observed in Site-1 Kumbi (Altitude-780m) and minimum (27) in Site-3 Keibul (Altitude-772). The variation of plant species may be because of the slight variation of altitude. As the six study sites are distributed as floating aquatic environment in KLNP Loktak Lake, there is favourable place of the plants in higher altitude and altitude represents a complex gradient along which many environmental variables change concomitantly. In all the six study sites, common distribution of ten dominant plant macrophytes viz., Ageratum conizoides, Hedychium coronarium, Leersia hexandra, Oenanthe javanica, Phragmites karka, Polygonum sagittatum, Saccharum munja, Thelypteris interrupta and Zizania latifolia was noticed. Individual dominant plant was recorded in other sites also viz., Azola piñata in site-6; Xanthium atrumarium, Polygonum orientale, Dichrocephala latifolia and Cymbopogon citratus in site-2; Arundo plinii, Cuscuta reflexa, Gnaphalium luteo-album, Hydrilla verticillata, Marsilia minuta, Saccolepis interrupta, Selvenia cuculata and Utricularia spp. in site-1. Variation of IVI value of dominant plant species was observed in this study. Even though 85 dominant plants were selected for all the 6 sites, however, maximum plant richness expressed in IVI was recorded in case of Zizania latifolia (Site-5, IVI-87.5) and minimum IVI in case of Xanthium strumarium (Site-2, IVI-1.13). The diversity pattern and habitats of macrophytes in KLNP Phumdi environment might be due to water availability along the altitudinal gradient and other environmental factors suited in the study sites and expected to be an important factor affecting the survival and fecundity of plant population. We need to conserve the natural habitat of KLNP thereby maintaining the luxuriant growth of the seasonal and perennial, macrophytes, so as to maintain the natural flora and fauna of the park. These plants are the food of man and animal therefore, it needs a proper care and attention to protect them from over exploitation. Considering the diversity pattern of habitats of Macrophytes in KLNP, a floating mat Phumdi environment with high floral diversity and unique vegetation assemblage, it has been suggested that this track and adjoining sites should be declared as ecologically sensitive area not only the World Heritage Site.

Loktak Lake is the largest fresh water Lake in the North-eastern India. Keibul Lamjao National Park (KLNP) is a floating-mat (Phumdi) park inside the Lake. Study deals with the inter-related approaches: micobiological study, free-listing, participant observation and preference ranking of the six study sites of KLNP. Generally, plant collection per day was about 600 kg of Hedychium coronarium J. Koenig which were extracted from the park and found to be the most preferable species; while Persicaria sagittata (L.) H. Gross, as the least among the selected plants. Microbiological analysis of water for the six study sites recorded high pollution as evidenced by high values of Standard Plate Count (SPC) for bacteria ranging from 73,500-96,500 and microbial analysis of MPN (Most Probable Number) of coliform bacteria varies between100 and 320/100 ml and faecal coliform 95 and 200/100 ml. Free CO2 concentrations varied at the surface from 2-60 mg/l and 6-70 mg/l at the bottom of the park. In the KLNP environment the higher CO2 and lower concentrations of dissolved oxygen (DO) might be due to the floating mat (Phumdi) nature, in which light and exchange of gases does not occur as it does in the natural water bodies.

Seasonal variations in the water quality of a tropical wetland dominated by floating meadows and its implication for conservation of Ramsar wetlands

Aquatic insect diversity of a protected area, Keibul Lamjao National Park in Manipur, North East India

Keibul Lamjao National Park (KLNP), a floating park in Loktak Lake, Manipur (India) was studied from Winter (WIN) to Post Monsoon (POM) for its zooplankton composition and some selected water parameters. The resultant data were subjected to multivariate techniques–Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). Analyses of water parameters with PCA revealed that the first PC axis (PC1) accounts for maximum variance in the seasonal data, explaining a variability of 91%. The PCA revealed that the seasonal variability in water parameters was due to the wet and dry cycle of seasons and the stations were distinguished on the basis of transparency and turbidity. Zooplankton abundance was dominated by copepods followed by cladocerans. Temporally, abundance of copepods reached a maximum during Post-monsoon (POM) (3 880 ind./L). Spatially, S6 was found to be most abundant of the other stations in zooplankton. Copepodites and nauplii larvae were the major components of zooplankton. The Rotifera were the least abundant among the three zooplankton groups. Brachionus formed the major component of Rotifera zooplankton at all the stations during the study period. In the Cladocera, Macrothrix was present during all the four seasons, while Pleuroxus, Oxyurella, Kurzia and, Diaphanosoma were rare. The CCA shows that maximal temporal variability in zooplankton abundance was explained by temperature and rainfall. ANOVA revealed no significant diff erence in mean zooplankton abundance among the seasons, but there was a statistically significant diff erence among the sites.

Over centuries, agricultural practices have undergone the transition from extensive and traditional to intensive and specialized. Thus, the weeds colonizing cultivated fields are subjected to major shifts due to increased use of herbicides, fertilizers and tillage. There are a total of 176 weed species in Agro-ecosystems of Himachal Pradesh and not less than 46 in maize. Weeds, in maize, are hardier in nature and compete with the crop significantly reducing its yield. Also, slow initial growth and wider spacing favour the growth of weeds even before crop emergence. Commelina benghalensis, Ageratum conyzoides, Echinochloa colona, Panicum dichotomiflorum, Cyperus iria, Digitaria sanguinalis, Polygonum alatum and Aeschynomene indica were dominant weeds observed under Kangra district conditions of Himachal Pradesh. The phytosociological study showed that the species which invaded the non-cropped lands are increasingly infesting the cultivated fields. In 2008, most abundant weed was Fimbristylis miliacea followed by Cyperus difformis, Eragostis tennela, Ageratum conyzoides, Ammannia baciferra, Bidens pilosa and Hackelia uncinata. In 2018, Ageratum conyzoides was the most abundant followed by Phyllanthus niruri, Panicum dichotomiflorum, and Commelina benghalensis. Ageratum conyzoides was the most important weed in 2008 followed by Echinochloa colona, Fimbristylis miliacea, and Digitaria sanguinalis, in that order. The Important Value Index (IVI) for individual weed species in the maize field crop in 2018 indicated that Ageratum conyzoides was again the most important weed species followed by Phyllanthus niruri, Echinochloa colona, Alternanthera philoxeroides, Aeschynomene indica, Commelina benghalensis and Digitaria sanguinalis. The weed species viz. Ammannia baccifera, Bidens pilosa, Brachiaria ramose, B. reptans, Dactyloctenium aegyptium, Fimbristylis miliaceaum, Galinsoga parviflora, Hackelia uncinata, Ipomoea pestgridis, and Physalis minima those recorded in 2008 were not found in the survey of 2018. Aeschynomene indica, Alternanthera philoxeroides, Amaranthus viridis, Echinochloa crusgalli and Oxalis sp. recorded during 2018 were not found in the survey of 2008.

The Lake Cluster of the Pokhara Valley (LCPV), a Ramsar site, has been invaded by several invasive alien plant species (IAPS), yet the introduction pathways of these species remain unknown. In this paper, the possible introduction pathways and invasion history of five wetland IAPS of the LCPV have been identified and reported for analysis. Direct field observations were combined with data obtained from the questionnaire survey with the local residents to identify introduction pathways and invasion history. Among five invasive alien plants, Pontederia crassipes and Pistia stratiotes were introduced as ornamental plants that escaped to wetlands and established their populations during 1980s and 1990s respectively. Similarly, Ipomoea carnea subsp fistulosa was introduced during the 1990s for fencing and soil bioengineering purposes. It is highly likely that Leersia hexandra and Alternanthera philoxeroides were introduced accidentally as none of the local residents interviewed could explain the purpose of their introduction. The local residents have noticed the occurrence of L. hexandra for >50 years while A. philoxeroides might have reached to the LCPV sometime between 2015 and 2020. The results suggest the wetland IAPS have been introduced to the LCPV both intentionally as well as accidentally, and that the prioritizing pathway management can prevent their future introductions.

Spiraea are beautifully flowering shrubs that are valued for their high decorative value, a variety of bush shapes and flower colors, abundant flowering, unpretentiousness and high resistance. The exact dates of flowering may vary depending on the climatic conditions of region, so the study of flowering periods in a particular region of introduction is relevant. The purpose of the study was to determine the flowering dates of the species Spiraea in the Botanical Garden-Institute of the Volga State University of Technology (Yoshkar-Ola, Mari El Republic). The observations were carried out in 2023. The objects of the study were 56 species and varieties in the exhibition "Fruticetum". The duration of flowering was 3 months – from May 6 to August 5. In the period up to mid–June, mainly plants with white flowers bloomed, and only 2 species with pink ones – S. Billardii and S. Densiflora. Since the second half of June, the flowering of pink-colored Spireas has prevailed. The distribution of the studied Spiraea into groups with early, medium and late onset and end of flowering has been carried out. A flowering calendar has been compiled. The species S. corymbosa had the longest flowering (56 days), also long-bloomed S. Rubella, S. Latifolia, S. Bumalda and its cultivar 'Antony Waterer', S. Salicifolia and its cultivar 'Alba', S. Humilis, S. Lemoinei, S. Syringaeflora, S. Rosthornii. The data obtained are of value to specialists in the field of landscaping. A limited number of Spiraea species are used in the plantations of settlements of the Mari El Republic, and thanks to the extensive collection of Botanical Garden-Institute, it is possible to enrich the range of Spiraea in urban plantings.

The muscle tissues of Channa punctatus and Anabas testudineus collected from the Loktak Lake (a Ramsar site) and its three major feeder rivers in Manipur, Northeastern India, were analyzed using high-performance liquid chromatography for the presence of residues of organophosphorus, carbamate, and synthetic pyrethroid pesticides. Pesticide residues of all the three types were detected in the fish tissues. Pesticide residues in Channa punctatus ranged from 0.002 – 0.043 µg g-1, and from 0.008 –0.027 µg g-1in Anabas testudineus from Loktak lake in pre-monsoon and post-monsoon seasons. Pesticide residues were detected only in Anabas testudineus (0.002 – 0.078 µg g-1) in Nambul river, while these were detected only in Channa puctatus (0.001 – 0.032 µg g-1) in Moirang river. In Nambol river, pesticide concentrations ranged from 0.002 – 0.026 µg g-1 in Channa punctatus, and from 0.004 – 0.005 µg g-1 in Anabas testudineus. Among the five pesticides detected, concentrations of dichlorvos residues detected in the present study (0.027 and 0.032 µg g-1 wet weight) exceeded the Codex Alimentarius maximum residue limit (MRL) of 0.01 mg kg-1 for animal tissues. The rest of the compounds were within the MRL. None of the pesticide residues was detected in the two fish species collected from the control or reference site. The present study indicates that pesticide contamination is emerging as a threat to the water quality and aquatic biodiversity of Loktak Lake, which calls for more detailed studies on the extent and magnitude of these threats.

A wetlandscape is a landscape characterized by the presence of numerous interconnected wetlands (Bertassello et al. 2018). Loktak located in the Manipur River basin in India is a unique wetlandscape that includes numerous floodplain wetlands and associated channels. It hosts the Loktak wetland, the largest freshwater body in the northeastern India, also designated as Ramsar site and the Keibul Lamjao National Park, the only floating national park in the world. Like any other wetlands in the world, Loktak wetlandscape is also under great threat due to the changes in the hydrometeorological conditions associated with climate change as well as the human interventions in the wetlandscape and its catchment. Loktak hydro-electric project, the major anthropogenic intervention in the wetlandscape has a huge impact on the hydrology and ecology of Loktak wetland complex and to Pumlen wetland complex to a less significant level (Trisal and Manihar 2002). This work investigates the multi- and cross-scale degradation of wetlands in the Loktak wetlandscape in a nested-framework by studying hydrogeomorphic dynamics at catchment scale, wetlandscape scale, and wetland complex scale. The catchment scale encompasses surrounding uplands and hillslopes. At the wetlandscape scale, which includes interconnected wetlands and associated channels, individual wetland boundaries are demarcated using historical Corona image and recent Sentinel-2 image. By comparing historic and recent boundaries, we found that six natural wetlands of area less than 1.5km2 have completely converted into other land use types and three small wetlands with area less than 1km2 get merged with bigger ones due to barrage-induced prolonged inundation. The wetland complex scale is a cluster of hydrologically interconnected wetlands of same or different types. Loktak wetland complex has not shown any prominent change in its extent, whereas Ikop and Pumlen wetland complexes have shrunken remarkably over time. The degradation of wetlandscape is evident from other factors such as proliferation and thinning of phumdis (floating biomass) and destruction of vegetation in the catchment. The cross-scale investigation suggests the influence of both natural and anthropogenic controls on the degradation of Loktak wetlandscape. The findings of this study and the protocols developed here will help to better understand the stressors of Loktak wetlandscape and elsewhere and could be instrumental in developing a conservation and management plan. Multi-scale management of wetlandscape include the catchment-scale measures such as afforestation, protection of hills and reducing the frequency of shifting (jhum) cultivation in hilly areas, wetlandscape scale measures such as control of waste dumping, control of channel modification for builtup and then wetland scale measures such as removal of invasive species from open water, and control of athaphum farming (method of farming using phumdis). Considering that a huge proportion of population in the valley depend on these wetlands for their livelihood, accounting their needs and making them a part of any effort for the management of this ecosystem has to be one of the primary goal.

INTRODUCTION:Land use and land cover changes vary in accordance with relief, climatic conditions and other socio - economic requirements of individuals. Land resources fulfil the primary and secondary human needs, i.e., food, shelter, industries, recreation, communication and economic security (Stamp, 1960). Land use is a phenomenon which undergoes ever changing with the growing needs of human beings. These changes in land use patterns are more specific in the marginal and climatically severe regions. Rapid expansion of human populations in the recent decades coupled with widespread unscientific land use practices have resulted into decline in the land to man ratio and shifting from an extensive cultivation practices to intensive ones (Oinam et al., 2005); (Kuniyal, 1996); (Ramakrishnan et al., 2000); (Bilsborrow and Okoth-Ogendo,1992). Therefore, sustainable utilisation of land resources becomes utmost important to achieve sustainable development and food security of the ever increasing human population (Oinam et al., 2004-05).The current study attempts to assess the land use land cover changes taking place in the catchments of Loktak Lake as a result of impoundment for hydropower generation. Literature pertaining to studies in land use and land cover changes for the area is scanty, even though many studies were conducted by different scholars on other important aspects. For instance, WAPCOS (1993) conducted an extensive study on Loktak Lake, focusing on issues and challenges pertaining wetland degradation. The report emphasises the need of multidisciplinary approaches to counter the problems of siltation, flood, watershed degradation, weed infestations, etc. Presence ofphumdis (floating vegetative mats) is one of the natural features of Loktak Lake. In a series of studies conducted by the Loktak Development Authority (LDA, 1996); (LDA, 1999) in the lake, the urgent need for control and management of phumdis was highlighted. Singh and Moirangliema (2009a) had also studied on phumdi proliferation in Loktak Lake. Water quality status, water borne morbidities of the lake and its conservation measures were studied by other authors (Laishram and Dey, 2014); (Singh and Devi, 2006). Some other researchers also contributed their thought on watershed management and conservation of the Lake (Singh and Moirangleima, 2009b); (Shamungaou, 2007); (Singh and Moirangleima, 2009c); (Singh and Moirangleima, 2012). The results obtained in all these studies hinted that the ecosystem and environment in and around the Lake has been changing gradually due to anthropogenic activities.RESEARCH METHODS:Loktak Lake and the Study Sites:Loktak Lake (24o25' N to 24o42' N and 93o46' E to 93o55'E) is spread over five valley districts of Manipur. It is the second largest freshwater in India covering an area of about 286 km2 at the elevation of 768.5 m amsl. During the rainy season the Lake water swelled up to ~490 km2. The lake has direct catchment area of ~980 km2 and indirect catchment area of ~7,157 km2. About 34 streams, coming from the western hills and the Imphal River drains into the lake. Loktak in actuality comprises of 20 water bodies of different sizes. The landscape becomes quite distinct during the dry season but the water bodies merged and forms single water spread during the rainy months. The current study area comprises of three hillocks within the lake area viz., Thanga, Karang and Ithing (Fig. 1). The hillocks are situated around 50 km south (on road distance) from the capital city, Imphal. The villages in the hillocks truly represent lake settlement and are spread over 3.22 km2. Development of road network in the state has made inroads into some of the larger and populous hillocks like Thanga and Ithing half a century ago. The hillocks in Karang remain untouched by the expanding road network and still represent a typical island settlement. There are 2458, 299 and 297 households in Thanga, Ithing and Karang village (Census, 2011), inhabiting a total population of 14316, 1832 and 1859 individuals. …

Loktak Lake is the largest natural freshwater lake of Northeastern India, characteristic by floating islands, known as Phumdis. The lake supports rich biodiversity including some globally threatened species, hence declared as a Ramsar Site. The lake facilitates hydropower, irrigation and provides a livelihood to the local villagers in the form of fishing and agriculture. Loktak Lake is deteriorating in recent years due to rapid urbanization, increased settlement and other anthropogenic activities. A study was, therefore, undertaken to assess the water quality and its trends for this important lake. The water quality of Loktak Lake was assessed in monthly intervals for a period of 3 years, using multiple water quality indices. Temporal distribution functions of the individual water quality parameters and indices were developed to assess the water quality trend of the lake. Overall water quality of this lake was found to be good throughout the year with slight deterioration during winter. However, the water of this lake was a little turbid and contained significant organic load.

ABSTRACTThe assessment of nutrient and heavy metal accumulation in lake sediments is essential for understanding their role in the ecohydrological dynamics of lake ecosystems, as sediments can function both as a sink and source of nutrients, metals and various contaminants aquatic ecosystem. The main objective of this study was to evaluate the concentrations of nutrients and heavy metals and their accumulation in the sediments across different sampling locations of Loktak Lake and to compare them against geochemical background values and sediment quality guidelines. The key findings of the study revealed substantial nutrient accumulation in sediments from the Keibul Lamjao National Park site, which can be attributed to the decomposition of organic matter from dense floating vegetative masses called ‘Phumdis’. Iron concentrations in sediments were significantly high, ranging from 909.83 to 1004 mg/kg and its enrichment is likely due to diffused surface runoff from the iron‐rich soils from the surrounding catchment entering the lake through feeder rivers and other anthropogenic influences. The average metal concentrations were in the order of Fe > Mn > Zn > Cu, and all values were below the average shale concentrations and the Interim freshwater Sediment Quality Guidelines (ISQG) set by the Canadian Council of Ministers of the Environment (CCME). The evaluation of the heavy metal pollution status of the lake sediments based on various pollution indices such as the contamination factor, degree of contamination, modified degree of contamination, geoaccumulation index, pollution load index and potential ecological risk index, suggested an overall low level of metal pollution in the sediments of Loktak Lake. The findings of this study provide a crucial baseline for understanding on the sediment‐associated nutrient and metals dynamics in Loktak Lake which can aid in the formulation of long‐term lake management strategies for preserving the ecological integrity and health of this precious lake ecosystem of the region.

To clarify the relationship between the timing and the duration of flowering among populations, plants, and individual flowers, the dates of flower budding, flowering and deflowering were monitored for ten woody species from March 1 to June 30, in 2005, 2006 and 2007, in temperate deciduous forests at three sites of Namsan, and individual plants from seven woody species were monitored from March 1 to May 31, in 2006. Total durations of flower budding, flowering, and deflowering varied among the plant species. Three durations of these phenological stages of Stephanandra incisa were the longest (74 days, 109 days, and 101 days, respectively), and those of Prunus serrulata var. spontanea were the shortest (7 days, 7 days, and 4 days, respectively). For each species, phenological durations varied among years but were similar among the study sites in the same year. There was no relationship between flowering time and flowering duration on the population level. On the plant level, the duration of flower budding was over 11 days in all specie; S. incisa had the longest duration (73.3 days), and that of Styrax japonica was long as well (29.0 days), while that of Prunus leveilleana was the shortest (11.3 days). The longer the mean flower budding duration, the greater the difference among the plants within a species. The flowering duration of for S. incisa was 92.2 days, while that of Forsythia koreana was 27.2 days. The flowering durations of all other species were <TEX>$10{\sim}20$</TEX> days. The deflowering duration was 92.0 days in S. incisa and <15 days in all other species. Differences among the plants in deflowering duration were smaller than those of the other phenological stages. In the species that flowered in April, the correlation coefficient between the flowering duration and the first flowering date was negative and significant. However, in the species that flowered in May, the correlation between flowering duration and the first flowering date was not significant. For individual plants of all species except for S. alnifolia, the earlier the flowering time, the longer the flowering duration. Differences between flowering time and flowering duration across years were significant in six species.

A study was conducted during August–November, 2024 at Thanga village in Bishnupur district of Manipur, India to study the plant bioresources and species diversity of home gardens in Thanga village which is a community closely tied to Loktak Lake’s ecological and cultural landscape. Home gardens play a very significant role in reservoirs of plant diversity and have been contributing immensely to biodiversity conservation, food security, and preservation of traditional knowledge. Given the rising vulnerability of forests to climate change and human disturbances, home gardens can be seen as a sustainable alternative for conserving plant diversity while supporting local livelihoods. A total of 70 plant species and 38 families were documented, with Zingiberaceae being the most dominant. The species were categorized into edible, medicinal, ornamental, fuelwood and construction uses. Species richness ranged from 8.71 to 12.56, with edible plants dominating. Diversity indices, such as Shannon-Wiener index and Simpson’s diversity index, indicated considerable biodiversity and evenness, and hence, the necessity of home gardens in maintaining ecological stability, ensuring food security, and preserving traditional knowledge. The study further emphasizes the home garden composition in relation to the surrounding environment, especially the impact of Loktak Lake. Loktak Lake provides much-needed ecological support, which influences plant growth and species selection in home gardens. The reliance of the villagers on these gardens for subsistence and livelihood security indicates the cultural and economic importance of home garden bioresources. It brought forward the imperative necessity of maintaining sustainable management practices to preserve biodiversity while challenging emerging changes.