Diversity of aquatic macrophytes found in the villages of Kallal Block, Sivagangai District, Tamil Nadu, India

Introduction

Macrophytes are aquatic plants that live near or in water. They can be floating, submerged, or emergent, with upright sections above the water's surface. The vast majority of aquatic macrophytes live in shallow regions such as lakes, ponds, pools, marshes, streams, rivers, and so on. Aquatic macrophytes, or giant aquatic plants, play an important role in freshwater environments, providing a variety of ecological, environmental, and social advantages. One of the key advantages of aquatic macrophytes is their ability to enhance water quality by absorbing excess nutrients, notably nitrogen and phosphorus, which can cause eutrophication and toxic algal blooms. By absorbing these nutrients, macrophytes help to reduce the effects of nutrient pollution, resulting in better aquatic habitats. Additionally, they provide critical habitat and refuge for a diverse range of aquatic creatures, including fish, invertebrates, and amphibians, so supporting biodiversity in these environments. Macrophytes extensive root systems also help to stabilize debris, minimizing erosion and increasing water clarity. Furthermore, these plants contribute to the carbon cycle by sequestering CO 2 , which aids in climate management. In terms of social benefits, aquatic macrophytes can improve recreational activities such as fishing and bird watching, as well as be used in bioengineering applications for wastewater treatment and shore stability. Overall, aquatic macrophytes are essential for the health and resilience of freshwater ecosystems, and they provide considerable ecological and societal benefits (Morris & Hargreaves, 1997) [3] . Aquatic macrophytes have received attention for their various therapeutic characteristics, making them useful in both traditional and modern medicine. Many species include bioactive chemicals with anti-inflammatory, antioxidant, and antibacterial properties. While aquatic macrophytes provide several ecological benefits, they can also have a number of drawbacks that affect freshwater ecosystems and human activities. One big issue is that excessive macrophyte development can cause overpopulation, which can impair water movement and lower oxygen levels in the water, potentially hurting fish and other aquatic species. This tendency, known as "overgrowth," can cause the production of dense mats that hinder recreational activities such as boating, swimming, and fishing, limiting access to waterways. Furthermore, the decomposition of huge quantities of aquatic plants can reduce oxygen levels in the water, resulting in hypoxic conditions that are harmful to aquatic life. In some circumstances, invasive macrophyte species can outcompete native flora, disrupting local ecosystems and diminishing biodiversity. Additionally, regulating excessive macrophyte development can be expensive and labor-intensive, necessitating mechanical harvesting or chemical treatments that may have negative environmental consequences. Thus, while aquatic macrophytes are necessary for healthy ecosystems, their uncontrolled proliferation can offer considerable issues (Sharma et al., 2016) [7] . Aquatic macrophytes can also have a number of negative consequences for freshwater ecosystems and humans. One major worry is that dense macrophyte populations can modify environments, favouring certain species over others and potentially contributing to biodiversity loss. This can occur when invading macrophytes outcompete native species, disrupting local food webs and ecological function. Furthermore, excessive macrophyte development can impede water flow in rivers and lakes, resulting to increased sedimentation, altering ecosystems and potentially harming fish breeding and nursery sites. Thick mats of aquatic plants can also promote mosquito population growth, which can be an annoyance to neighboring people and present health problems because of disease transmission. Additionally, controlling overgrown macrophyte populations frequently calls for the use of herbicides and other control methods, which may have unforeseen effects on water quality and non-target species. Accordingly, aquatic macrophytes are crucial for the health of ecosystems, but if they grow out of control, they may cause serious ecological and socioeconomic problems (Kumar et al., 2020) [2] . The most effective integrated management plans frequently incorporate mechanical, chemical, and biological techniques. The study's goals were to identify medicinally significant macrophytes, create a catalog of weeds, and learn about their biology, growth habits, origins, and habitats. All things considered, this study offers a starting point for sustainable management plans, frequent observation, and community education to preserve the diversity of native macrophytes while managing alien populations.

Materials and Methods

From August 2024 to August 2025, a survey of the diversity of aquatic macrophytes was carried out in villages in the Kallal block of the Sivagangai district, including ponds, irrigation channels, canals, and other wet areas. Kallal is the 12 th block in the Sivaganga District. Kallal Block is located at 9.9863°N and 78.6652°E, with an average rainfall of 904.7 mm and an average temperature of 32.9°C. The overall size of the block is roughly 362.33 square kilometers. This block contains 44 villages. We investigated aquatic macrophytes in villages located in this block (Fig. 1) Fig. 1: The map depicts the study area of Kallal block villages in Sivagangai district Different approaches were employed to identify the species of aquatic macrophytes, including visual identification and oral interviews with the locals. The people who live in these villages provide information about undiscovered aquatic plants, including their local names, economic significance, therapeutic value, and management. Other aquatic plants were discovered through website articles and mobile applications, as well as diverse literary sources and experts. During the survey, aquatic macrophytes are photographed and validated by multiple sources. Photography was done using a Nikon D3500 digital camera and Canon 70-300 mm lenses. Every two months, we conduct observations. The aquatic macrophytes were categorized alphabetically by botanical name, family, vernacular names, and therapeutic application (Table 1).

Results and Discussion

Based on Family

The most species-rich families were Poaceae (11.26%, 8 species), Cyperaceae (9.86%, 7 species), Lemnaceae (7.04%, 5 species), and Pontederiaceae, Nymphaeaceae, Salviniaceae, and Hydrocharitaceae (5.63%, 4 species each) (Table 1). According to this study, Christin et al. (2008) [1] discovered that Poaceae dominate because they are wind pollinated and have dangling anthers, while Cyperaceae dominate due of their adaptability to both terrestrial and aquatic habitats and their C 4 photosynthetic pathway.

Based on Morpho-Ecology

Emergent 47.89% contains 34 species, floating 33.80% contains 24 species, submerged 14.08% contains 10 species, and floating and submerged 4.23% contain 3 species (Table 1). Emergent macrophytes ability to root in the substrate while their leaves and stems emerge into the air allows them to efficiently access sunlight, nutrients and atmospheric oxygen, giving them a competitive advantage over other aquatic plant types.They are well-suited to the fluctuating water levels typical of wetlands and effectively remove nutrients and organic matter from wastewater. Comparable study findings were also published by Rezania et al., (2021) [5] .

Based on Lifespan

Annual types account for 21.13% (15 species), perennial types for 74.65% (53 species), and annual & perennial (varying depending on environment) for 4.23% (3 species) (Table 1). As stated by Peixoto et al., (2022) [4] perennial plants frequently outgrow annuals because of their competitive advantages, which include deeper root systems that allow access to deeper nutrient pools and stability in nutrient-poor or changing environments. The absence of disturbance is essential because it enables perennials to build up biomass over longer periods of time and create root systems that endure rather than being reset by the annuals' life cycle.

Based on origin

Asiatic species make up 46.4% of the 71 species, while non-Asiatic species make up 53.5% (Table 1). Because of their high food availability, adaptability to different environmental conditions, and lack of natural enemies in their new habitat, nonasiatic macrophytes frequently prevail. Additionally, these plants have the ability to change the water's physical and chemical properties, which may benefit their own growth at the expense of native species. Similar study results were also reported by Schultz et al. (2011) [6] .

References

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