Introduction
Water hyacinth is a perennial aquatic plant which freely floats in tropical as well as sub-tropical waters. Water hyacinth is native in South America but has since been introduced to many regions. This plant has glossy, broad, ovate and thick leaves and rises up to 1 meter above the water surface.
Water hyacinth is among is among the fastest growing plants ever known and reproduces through stolons or runners that form daughter plants. There has been raging debate on the overall significance of water hyacinth on human society. Despite that the plant has some economic and ecological benefits; its adverse effects are overwhelming.
The presence of Waterhyacith has been associated with numerous economic and ecological damages. Water hyacinth has great harm on the local ecosystems. Water hyacinth degrades water quality and affects habitats for aquatic life. This research paper will explore, discuss and analyze how water hyacinth harms the local ecosystem.
Identification of Waterhyacith
Water hyacinth has been ranked as one of the worst invasive species. The reputation of water hyacinth has been doomed due to its ecological and economic effects. Being a native plant in South America, water hyacinth has spread to other regions of the world. Water hyacinth produces beautiful flowers, though its problems are higher. Water hyacinth can be easily identified since it freely floats on water surface.
This plant has dark green, shiny and glossy leaves. The leaves are elliptical and round in shape. The leaves of water hyacinth are approximately 6 inches wide alongside being waterproof. Another key feature of water hyacinth is that it rises over 3 feet above the water surface.
The roots of water hyacinth are distinctive and hang below water surface, whereby they have a feathery appearance. Despite the harmful effects of water hyacinth on ecosystems, the plant has very attractive flowers (Villamagna Murphy, 2010).
Effects of Waterhyacith on local ecosystems
Water hyacinth has great harm on the local ecosystem and affects aquatic life and water quality. This plant blocks photosynthesis thus degrading water quality. The reduction of water quality through deprivation of oxygen has a cascading effect on aquatic life. Fish, plants and other sea life are adversely affected by this phenomenon. The biological diversity is greatly degraded by water hyacinth.
This is because water hyacinth has a negative effect on submersed plants. Water hyacinth also interferes with immersed plant communities through crushing and pushing them. By so doing, the general ecosystem is impacted. Animal communities are negatively affected through the elimination of plants as well as blocking the access of water which the animals rely on for nesting and shelter (Mariana et al, 2006).
The effects of water hyacinth are enormous on the ecosystem. This can be attributed to the fast growing nature of the plant. Water hyacinth grows very dense to the point that a single acre of the weed weighs over 200 tons. This is a great catastrophe to the ecosystem in the sense that it blocks oxygen in the waters thus inhibiting aquatic life.
The thick and dense mats formed by water hyacinth overwhelm lakes and rivers thus inhibiting biological and economic process. The life of other plants and animals is jeopardized by the rapid growth of water hyacinth. The enormous growth and concentration of the plant decreases water flow as well as leads to oxygen depletion.
As a result, a good environment for mosquito breeding is developed. Native plant species are overwhelmed by the plant thus leading to their elimination. Based on these changes, water hyacinth alters the entire ecosystems which animals and plants rely on (Weijden and Bol, 2007).
Degradation of water quality
Water hyacinth has a distinctive effect on water quality. Past research has shown that the dense mats formed by the plant have adverse effects on water quality. The plant forms dense and interlocking mats which affect the oxygen flow in the water. As a result of the dense and interlocking mats formed by the weed, the dissolved oxygen concentrations declines, hence degrading water quality.
A low level of phytoplankton productivity also takes place which in turn dooms water quality. The higher levels of sedimentation resulting from the dense mats as well as the complex root structure of water hyacinth also affect water quality.
Water hyacinth leads to high levels of evapo-transpiration rates due to the dense leaves of the plant. This is in comparison with the evaporation rates hence leading to heavy sedimentation (Villamagna Murphy, 2010).
The levels of temperatures and PH in waters are also affected by the plant. Water hyacinth destabilizes temperatures and PH levels in the lagoons. This scenario prevents stratification thus increasing mixing in water levels. This phenomenon affects water quality since oxygen levels are degraded. The rates and levels of photosynthesis are also greatly inhibited by water hyacinth.
Water hyacinth does not produce oxygen as compared to other submerged vegetation and phytoplankton. This leads to low levels of dissolved oxygen concentration thus negatively affecting water quality.
The capacity of the plant mats determines the level of oxygen concentrations. High concentrations of water hyacinth mats lead to low penetration levels of light into water columns thus inhibiting photosynthesis (Mariana et al, 2006).
Decrease in dissolved oxygen concentrations
Water hyacinth has been associated with the degradation of oxygen in water. This is in comparison with other aquatic invasive species like Sagittaria lancifolia and Hydrilla verticillata. Research has shown that water hyacinth greatly reduces oxygen concentration.
Water hyacinth has been categorized as the only plant leading to a massive decline in average levels of oxygen concentrations. An inverse relationship between water hyacinth and dissolved oxygen concentration has been identified. a significant decrease in the amount of dissolved oxygen beneath water hyacinth mats in relation to that of open water has also been established.
This offers a clear picture of the negative effects of the plant in decreasing dissolved oxygen concentration (Villamagna Murphy, 2010).
A point of concern is that the rate of decreasing oxygen concentration is not constant. The size of a water hyacinth mat that can cause a significant decrease in oxygen varies from one region to another.
Over 25% of cover in 0.05ha can decrease oxygen concentration to levels which threaten aquatic life mostly fish survival. Nevertheless, a negative relationship exists between dissolved oxygen and water hyacinth concentration (Streever, 1999).
In the case of dissolved oxygen, areas infested with water hyacinth usually demonstrate lower ranges as compared to waterhyacith free waters. Shorelines without the plants or with lower concentrations have high levels of dissolved oxygen. This is in comparison with water hyacinth free regions.
The absence or decline of dissolved oxygen has adverse effects on the ecosystem. Low levels of dissolved oxygen inhibit plant growth and survival of aquatic life. The low concentration of dissolved oxygen is a result of blockage by the water hyacinth mats.
The metabolic activities of aquatic life are jeopardized thus leading to extinction of some of the animals, plants and insects. This leads to loss of biodiversity, which is in this case a great harm to the ecosystem (Weijden and Bol, 2007).
Absorption of heavy metals
Alongside the decrease of oxygen concentration, water hyacinth absorbs heavy metals. Water hyacinth is dangerous in the sense that it absorbs large amounts of nutrients in the water column as well as heavy metals. This is a serious problem in relation to aquatic life.
The mercury concentrations of water hyacinth are very high. Research on water hyacinth in California indicated that water hyacinth leaves had same mercury levels as the sediments beneath. Poor disposal of the plant on the environment will definitely lead to contamination.
This will lead to ecological problems since animals and plants which depend on the contaminated environment will be affected. Nevertheless, the ability of water hyacinth to absorb large amounts of nutrients justifies its use as a tertiary or secondary biological alternative for waste water treatment (Streever, 1999).
Water hyacinth has a higher capacity of holding heavy solids as compared to shorelines without the plant. Water hyacinth waters have a higher turbidity as compared to clear waters. The levels of suspended solids in infested waters are alarming.
Water hyacinth traps phytoplankton and detritus which in turn affect water quality. Water which would have otherwise been fit for domestic use is rendered useless. High level of suspended solids inhibits zooplankton organisms hence decreasing energy transfer. The safety of human transport and other recreational activities in infested waters is jeopardized (Mariana et al, 2006).
Alteration of water PH levels
Water hyacinth affects pH levels and free carbon dioxide. PH levels are greatly decreased by the presence of water hyacinth. On the other hand, a high level of free carbon dioxide exists in areas infested with water hyacinth. In comparison with water hyacinth free shorelines, areas infested with the plant have a higher free carbon dioxide.
These high carbon dioxide levels are as a result of respiration, decay and the decomposition process of water hyacinth. Water hyacinth mats which are dense and large in size also prevents free entry of oxygen. This phenomenon is very harmful to aquatic and human life.
Oxygen demand for aquatic life is doomed, hence leading to death of some species. This leads to decline of biodiversity, thus illustrating the harm of the plant on the local ecosystem (Richard et al, 2011).
The high absorption rate of water hyacinth on nutrients is harmful to the environment. This is because it destabilizes PH level of the waters as well as the surrounding environment. The high absorption rate of nitrate, ammonium and phosphate can not only cause ecological harm but also affect aquatic and human life.
Despite that the high intake capacity is useful in reducing nutrient concentrations; it may lead to environmental contamination. Land on which the plant is disposed will be affected by the chemicals. This will have adverse effects on plants, animals and humans (Villamagna Murphy, 2010).
Depletion of Nutrients
Water hyacinth has a great impact on the ecosystem since it affects the overall nutrient composition. This may lead to the disappearance of some of the plant species or animal species which depend on them. Existence of water hyacinth leads to a high decrease in phosphorous and nitrogen. This calls for continuous control of the plant so as to counter its negative effects on the ecosystem.
Despite that waterhyacith provides phytoremediation, it leads to significant nutrient loss. This however depends on the concentration of water hyacinth. In light with this scenario, the decrease in nutrients affects the biological process of the plants and animals. Plant and animal loss will definitely occur thus demonstrating the effects of water hyacinth on the ecosystem and biodiversity (Streever, 1999).
The levels of nitrate concentration as a result of water hyacinth are lower compared to shorelines without water hyacinth. The average of nitrate concentration in water affected by water hyacinth is significantly lower as compared to that of shorelines free from the plant.
This is associated with absorption of nitrates by water hyacinth. The high capacity of nitrate absorption by water hyacinth is hazardous since it affects the overall concentrations of nitrates in the waters. This has great negative impacts on PH levels and also on the aquatic life (Weijden and Bol, 2007).
Increase in Water temperatures
Water temperatures in water hyacinth infested areas are slightly above average. Research shows that the average temperatures of water in areas infested with water hyacinth is higher compared to the shoreline temperatures. The difference in water temperature would not occur without the water hyacinth. This clearly shows the effects of water hyacinth in influencing water temperatures.
Higher water temperatures are attributed to the dense mats of the plant, which in turn hinders transfer of heat. Decay of organic matter resulting from the water hyacinth also leads to heat generation hence leading to temperature rise.
Temperature fluctuations in areas infested with water hyacinth is hereby a common phenomenon. Breeding of insects like mosquitoes is hereby likely as a result of the temperature changes (Richard et al, 2011).
Breeding of harmful insects
From another perspective, water hyacinth offers favorable conditions and environment for the breeding of mosquitoes and other animals and insects. The breeding of these insects like mosquitoes will definitely threaten human life since it leads to diseases.
Snails also get a prime habitat as a result of the water hyacinth. A good example of the snail species is the parasitic flatworm. This is a dangerous species of snails which causes schistosomiasis (Mariana et al, 2006).
Water hyacinth forms good breeding places for mosquitoes and other insects. The prolific and high growth of water hyacinth leads to excellent breeding areas for harmful insects like mosquitoes. Incidents of malaria, skin rash, encephalitis, cough; gastrointestinal disorders, bilharzias and schistosomiasis are very rampant in areas infested by water hyacinth.
Water hyacinth is harmful to aquatic life since it reduces the concentration of oxygen by de-oxygenating the water. Nutrients for young fish are also reduced. This is due to the high absorption rates of nutrients by water hyacinth.
The effects of water hyacinth are diverse and a catastrophe for aquatic life. The large and dense mats of water hyacinth block water supply and thus, affecting local subsidence fishing. This is an ecological disaster which calls for urgent measures in addressing the problem (Streever, 1999).
Inhibits fishing and transport
Water hyacinth has been blamed for starving subsistence farmers and will become a major problem if not controlled. This is associated with the diseases it enhances through the breeding of snails and mosquitoes which threaten humans.
The blocking or covering of waters by water hyacinth also inhibits fishing. Invasion of water hyacinth into waters associated with human activities can easily unbalance natural lifecycles. Aquatic life can hereby suffer a fatal blow as a result of the waterhyacith. This in turn contributes to loss of biodiversity (Weijden and Bol, 2007).
Lack of controlling and managing water hyacinth will lead to total coverage of ponds and lakes. This can have unprecedented effects on the local ecosystems. Covering of water deprive the native aquatic plants light and oxygen thus killing them.
Fish and other aquatic life will also be harmed since their food which consists of aquatic plants is no more. Death of aquatic plants and animals translates to loss of biodiversity (Villamagna Murphy, 2010).
Water hyacinth has a serious impact on local ecosystems in the sense that it inhibits free movement of aquatic life and humans. It has become common knowledge that water hyacinth inhibits water activities. For instance, boating, fishing and other human expeditions are also obstructed by water hyacinth.
The robust growth of water hyacinth outstrips other aquatic life. This leads to unnecessary competition for survival thus leading to near eradication of some of the species (Tacio, 2009).
The effects of water hyacinth on fishing and transportation are immediate. This is due to the thick mats and covering of the waters by the plant. Access to the beaches is hindered by waterhyacinth. This is due to the dense mats of the plant which hinder human transport. The dense mats formed by waterhyacinth hinter fishing. The movement of fish and other aquatic life is adversely affected by the water hyacinth.
This is an ecological problem in the sense that free movement of the aquatic life is hindered. On the other hand, water hyacinth inhibits irrigation, water treatment and water supply. These are natural and human processes which ought to be facilitated for sustainable coexistence.
Without proper water treatment and supply, biological and environmental catastrophes can emerge. For instance, the contaminated water is both harmful to humans and aquatic life. This is a clear manifestation of the hazardous nature of water hyacinth on the (Richard et al, 2011).
Reduction in biodiversity
Water hyacinth is an ecological disaster due to its prolific growth. This has resulted to its categorization as an ecological nuisance. The fast rate of growth of water hyacinth leads to covering of water surface thus affecting the growth and survival of other aquatic life. The fast proliferation of water hyacinth threatens the survival and development of aquatic species.
The effects of water hyacinth on water temperatures, photosynthesis, PH and nutrients are a serious threat to the survival of other aquatic life. For instance, the effects of water hyacinth in preventing penetration of light are unacceptable. Based on this phenomenon, the adverse effects of water hyacinth on the ecology are demonstrated (Mariana et al, 2006).
Water hyacinth has a serious effect on biological diversity. The prolific growth and spread of the plant has negative impacts on native submersed plants. Immersed plant communities are also altered by the growth of water hyacinth. This is because water hyacinth has fast growth and as a result pushes and crushes the native plants. Animal communities and other aquatic life are also altered by water hyacinth.
This is because the plant affects the local environments by altering temperatures, oxygen, PH and inhibiting penetration of light. By eliminating some of the plants, the animal communities are also affected. This is because the animals depend on the plants and vice verse.
Fish and other aquatic life usually disappear due to the changed environments in aspects of temperatures and PH. A serious human problem resulting from water hyacinth is that it results in the breeding of dangerous animals and insects.
For instance, areas infested with water hyacinth have higher chances of snakes and crocodiles. This ecological problem is a not only a threat to the human species but also to the entire biodiversity (Tacio, 2009).
Control of Waterhyacith
Due to the adverse effects and harm of water hyacinth on the environment, there is the need for prevention and control. Research has established different ways in which the weed can be eliminated or managed. At present, there are different control approaches for controlling the rapid spread of water hyacinth. The harmful effects of water hyacinth on the ecology and economical prospects have called for its control.
Chemical, biological and physical control mechanisms have been established. Despite that each control mechanism has its benefits; they have also reported diverse weaknesses and drawbacks. Chemical through the use of herbicides affects communities and environment, thus the need to abandon it.
In addressing the problem of water hyacinth, there is a need to identify and administer the best control mechanism. Mechanical approaches of controlling water hyacinth have been widely used. In this approach, dredgers, mowers and other manual extraction methods are used. Nevertheless, this approach is costly and is not possible in large areas.
On the contrary, mechanical approaches for eradicating water hyacinth also offers only short-term solutions. Biological approach to eradication of water hyacinth is most favored due to its long-term and short-term effects. This is not only a sustainable but also an economical approach to controlling the weed (Tacio, 2009).
Manual or mechanical control
Physical control is mostly applied in short-term basis and in small scale. Mechanical methods are the best approach in providing short-term solutions. Nevertheless, this approach is costly and requires both machinery and human labor (NSW Department of Primary Industries, 2010).
Early control using physical means targets concentrated areas. Physical methods remove the weed from their mats and dump them on land to die. Manual removal of the weed has proved successful in small scale as especially in farm drains and dams. However, the high rate of growth of water hyacinth makes it hard to attain total eradication. This approach is only successful when the rate of removal is higher than the plant’s rate of re-growth. From another perspective, physical of manual removal is not successful in large scale. This is widely due to the higher costs and labor (Denise et al, 2007).
Research has shown that mechanical control of water hyacinth is at times effective. Large infestations of the weed have been manually eradicated though at a higher cost. The time and cost of eradicating water hyacinth through manual means is high. It order to attain success, the removal should be done before flowing and seed set of the water hyacinth (NSW Department of Primary Industries, 2010).
Chemical removal
The use of herbicides in the removal of water hyacinth has been overwhelming in recent days. Chemical removal of water hyacinth has proved successful, whereby it has been applied for years in different regions. The success rate of using chemical methods is higher as compared to manual methods.
Nevertheless, there has been high concern for the health of communities as well as the environment in relation to chemical removal. In areas where people wash and collect drinking water as well as fishing, chemical application can turn hazardous. A number of herbicides have been registered which help in the control of water hyacinth. High volume spraying is the most used approach in the application of herbicides.
Handgun power sprays from the banks or on a boat can be adopted in applying the herbicides. Aerial spraying of herbicides can also be considered for large infestations. Herbicides should be considered in growing season mostly in Spring so as to enhance effectiveness.
Spraying recklessly can result in environmental and human catastrophes. Spraying on heavy infestation leads to sinking of the mats, which eventually rot. This can result into ecological disasters through de-oxygenation of water hence potentially killing aquatic life like fish.
In this case, spraying should be consciously undertaken by spraying only portions like a third of the area at a time. Physical or manual removal of some of the weeds before spraying is also advantageous and sustainable (Denise et al, 2007).
Biological
Biological methods of removing water hyacinth have been the most recommended due to their sustainability and ecological friendliness. Biological researchers have identified insects which can be effectively used to combat the spread of water hyacinth.
Two weevil species including neochetna bruchi, neochetina eichhomiae and moth species, Xubida infusellus, and niphograpta albiguttalis have been discovered to help control water hyacinth. These insects have proved to be successful in destroying the spread of water hyacinth.
The insects which feed on leaves by creating small scars have great effect in controlling water hyacinth. The laying of eggs by the insects on the water hyacinth leads to infection by fungi and bacteria thus causing the plant to be waterlogged and ideas.
Nevertheless, the inactivity of these insects during winter makes it hard for them to be relied on. Neochetina bruchi on the other hand has proved to be reliable during winter hence complements the inactivity of the other insects (NSW Department of Primary Industries, 2010).
It is however notable that biological control can not be solely applied in control of the weed. Biological control only reduces the prolific growth of water hyacinth but does not lead to total eradication. Biological control ensures substantial reduction in growth rates and flowering thus countering the proliferation of water hyacinth.
The damages on the plants lead to sinking of the mats thus reducing their effects. Since chemical and mechanical control techniques are quite expensive and inefficient, biological removals offer the only suitable approach in controlling water hyacinth.
Researchers have confidence that biological methods are more resilient and effective as compared to the use of herbicides and mechanical control. This is the most sustainable approach to combating invasive water hyacinth, hence reducing their ecological damages (Denise et al, 2007).
Other control mechanisms to water hyacinth include cultural control, mulching, windrowing, and managing flood-stranded infestations. In the case of cultural control, nutrients run to infested areas should be limited. Reduction of water levels in dams and drains can significantly reduce water hyacinth.
Introduction of salty water into infested waterways can also help in combating the spread of water hyacinth. Flood-stranded infestations should be managed by using Earthmoving equipments to remove water hyacinth. This is applicable to verges and roads, which helps in breaking down the water hyacinth.
Windrowing water hyacinth with tractor-mounted blade is an effective approach to removing water hyacinth (NSW Department of Primary Industries, 2010).
Conclusion
The study has clearly demonstrated the harm of water hyacinth on the local ecosystems. Water hyacinth has greatly impacted on the physico-chemical environments thus affecting the ecosystems. Based on the research, water hyacinth affects local water temperatures, PH, concentration of dissolved oxygen, photosynthesis and nutrients in the water.
These influences have great harm on the local ecosystems by altering the normal environments for biological, cultural and economic activities. Aquatic life is adversely affected by the changes in the water environments thus leading to eradication of some species. Water hyacinth has led to significant reduction in biodiversity in infested areas due to the alteration of favorable conditions for survival aquatic plants and animals.
Based on these problems, effective water hyacinth control measures should be adopted. Chemical, biological, mechanical and cultural control methods should be considered. Cultural and biological methods of water hyacinth control are most sustainable hence the need for their prioritization.
References
Denise, B. et al. (2007). Undesirable Side-Effects of Water Hyacinth Control in Shallow Tropical Reservoir. Freshwater Biology. Vol 52 (6), p1120-1133.
Mariana, M. et al. (2006). An Experimental Study of Habitat Choice by Daphnia: Plants Signal Danger More than Refuge in Subtropical Lakes. Fresh Water Biology. Vol 51 (7), p1320-1330.
NSW Department of Primary Industries (2010). Water Hyacinth- Weed of National Significance. Web.
Richard, M. et al. (2011). Invasive Plants as Catalysts for the Spread of Human Parasites. Neobiota. 9.1156.
Streever, W. (1999). An International Perspective on Wetland Rehabilitation. London: Routledge.
Tacio, H. (2009). Water Hyacinth Ecological Value, Environmental Impacts. Web.
Villamagna, M. Murphy, R. (2010). Ecological and Socio-economic Impacts of Invasive Water Hyacinth (Eichhornia Crassipes): A Review. Freshwater Biology. Vol 55 (2), p282-298.
Weijden, W. and Bol, L. (2007). Biological Globalization: Bio-Invasions and Their Impacts on Nature- The Economy and Public Health. New Jersey: McGraw Hill.