Anthropogenic Impact on Mangrove Ecosystems - Term Paper Example

Anthropogenic impact on mangrove ecosystems Mangroves form one of the most important ecosystems in the world. Itcomprises of salt tolerant tree species established at the tropical coasts. However, these ecosystems face anthropogenic threats such as overexploitation, reclamation, climate change, and pollution. This paper looks at the effects of human activities on these important ecosystems with the aim of reducing or minimizing such impacts and thus, conserve, manage, and protect such ecosystems for sustainable use. It is therefore, the duty of every human being to conserve mangrove ecosystems in order to avoid extinction of biodiversity and degradation of the ecosystem, which can sometimes be irreversible. Discussion Mangroves ecosystems are established on the terrestrial marine boundary on sheltered tropical coasts and are vulnerable to both natural and anthropogenic disturbances (Ghosh, 47). Man has lived with the mangroves for a long time and having little contact and exploiting its resources in small scale. However, recent unsustainable use and exploitation of mangrove ecosystems has contributed to extinction and loss of these vital ecosystems. Moreover, direct as well as indirect anthropogenic influences play a major role in determining mangrove composition and extent of coverage globally. Mangroves are salt tolerant tree species and examples include Rhizophora mangle, Avicennia germinans, Laguncularia racemosa, Conocarpus erectus among others (Guo, 401). Mangrove ecosystems form habitant for various biodiversity especially invertebrate fauna such as penaeid shrimps, spiny lobster and over 200 species of fish threatened globally. Human activities cause disturbance of the mangroves. Such activities include: 1 Overexploitation or unsustainable extraction of the mangrove tress and fauna Man continues to harvest mangrove trees for fuel wood, poles, charcoal, and timber for construction purposes. Moreover, mangrove bark is used for commercial production of tannin (Alfaro, 1087). However, small scale and selective extraction of mangrove pose a little challenge on the entire ecosystem, but leads to death of individual trees. Despite being small scale, clear cutting of mangroves contributes to rapid concentration of sulfide in the soil as well as soil acidification. This negatively affects seed regeneration on cleared lands and thus the reason for declining mangrove yields. Man has harvested mangrove fisheries for several years. Some of the fish products extracted include finfish, mangrove oysters, and shellfish. However, extraction of such resources in large numbers for commercial purposes has disrupted mangrove food webs and food chains (Jess et al, 414). Consequently, large-scale extraction of mangrove trees for extraction of wood products or mangrove land reclamation causes a reduction in fish yields since breeding grounds and fish nurseries get destroyed in the extraction process. In addition, man has introduced some species in mangrove ecosystems for instance, the introduction of Tilapia mossambica (Ellison, 219). The introduced species pose stiff competition for available resources in case the species naturalize and lack natural enemies or diseases that check on their population. Moreover, such species may feed on the native species thus leading to displacement and extinction of the endemic species. 2 Pollution of the mangrove ecosystem Human activities near water bodies lead to pollution of the mangrove ecosystem. For instance, oil exploration, drilling, production, transportation through oil pipelines, tanker accidents, as well as international elimination of ship’s ballasts tankers lead to oil pollution of the mangroves. The oil released into the mangrove ecosystem accumulates in the mangrove roots and thus leading to death of several invertebrates, turtles, and fish (Benson & Joseph, 238). The presence of oil in a mangrove ecosystem results in continuous release of toxic hydrocarbon materials into the water system, thus leading to water poisoning. The fauna found in an oil polluted mangrove environment experiences difficulty in water and oxygen uptake since oil clogs the breathing system of the animals resulting in suffocation and death. Moreover, oil pollution of mangroves results in their death since their roots get covered with oil and therefore, hindering respiration and absorption of minerals and water necessary for plant growth (Benson & Joseph, 238). The death of fauna and flora due to oil pollution causes loss of biodiversity, which can later transform to extinction of the organisms. In some cases, it may take a long time before regeneration of the affected mangrove plants, and thus affecting the supply of the mangrove products to the humankind. Further, the impacts of oil pollution might be adverse since it may compromise the integrity of the mangrove ecosystem. This may affect the normal functioning and provision of services of the mangrove environment. Furthermore, mangroves face thermal pollution from power plant cooling mechanisms. Within the tropics, cooling towers tend to be impractical since condensers depend on water from local water bodies for cooling purposes. This anthropogenic action causes a rise in water temperatures by 35 – 40o Celsius (Maitree, et al, 8). A rise in water temperatures affects the normal growth and functioning of the mangrove plants. For instance, there occurs a reduction in the leaf index and area of the mangrove plants, achlorophylly, increased photorespiration, and enhanced net photosynthesis. Moreover, the presence of an outflow pipe from a power plant contributes to increased levels of current flow, which enhances sediment flow of the mangroves nearby (Maitree, et al, 20). This adds to species loss since some of the trees eroded and destroyed formed part of habitats for invertebrates and other living organisms. Consequently, the rise in water temperature contributes to the decline of species richness of mobile and sessile invertebrates, thus affecting the biodiversity. Apart from oil and oil products which form the main sources of mangrove pollution, mangroves ecosystems experience pollution from other elements such as mercury, sewage disposal from industries, institutions and residential places, heavy metals generated from industrial activities, urban runoffs, pesticide runoff, tailings as well as compounds such as sodium hydroxide, (Richards & Bohnsack, 41). In addition, mangroves receive pollution from solid wastes dumped within its ecosystem and environment. These elements cause eutrophication of the water bodies and thereby degrade the mangrove ecosystem, thus reducing or terminating its productivity, functions, and services to humanity. For instance, enhanced water temperatures and sewage load results into an increased concentration of Vibrio spp responsible for seafood poisoning more so in shellfish collected from mangrove environments (Sathya & Sekar, 31). Feeding on the shellfish can result in healthcare problems and even death in extreme cases. Consequently, enhanced eutrophication and sedimentation arising from urbanization contributes to loss of several mangrove trees species. Coastal hotels as well as resort complexes also contribute to mangrove pollution by disposing off their sewage loads into the nearby mangrove environments, thus compromising its integrity. 3 Destruction of the mangrove due to land reclamation for non extractive mangrove uses Reclamation refers to the process of making unproductive lands more productive through for instance, land filling, fertilizing, or irrigating (Snedar, 43). These processes result in the creation of more land for agriculture or for habitation. Therefore, human being may not be in a position to recognize the importance of the mangrove and thus attempt to convert it to ecosystems that are more productive for instance, clearance of the marshy and swampy areas for cultivation or settlement. For instance, a mangrove ecosystem might be reclaimed to find land for developing large cities and industries. This results in the loss of mangrove ecosystems and other organisms depending on the system for survival. Human beings also reclaim mangrove ecosystems to pave way for the establishment of tourist resorts and hotels, airport construction and expansion, road construction among other reasons (Tom, et al, 45). Therefore, mangroves are reclaimed to provide space for construction of urban as well as tourist developments. Most governments provide permits for mangrove reclamation since the ecosystem is not of much value as compared to the planned development. However, in some regions, mangroves are of economic importance since they provide tourist attraction sites. For instance, the Caroni swamp in Trinidad is a tourist attraction site since it forms part of the breeding site of scarlet ibis. This leads to generation of foreign exchange and thus, boosting respective countries’ economies. Despite the income generated from the tourist activities, massive damage to the environment has also occurred in the process (Tom, et al, 46). For instance, boat wakes contribute to bank erosion as well as fringing tree collapse. Moreover, mangroves provide perfect sites for the construction of shrimp, salt, and fishponds, thus creating more fishing grounds and ensuring food security. 4 Impacts from human induced climate change due to increased concentration s of CO2 levels. Climate change refers to the gradual shift in the average weather conditions to a more unpredictable and uncommon weather patterns (Valiela, Jennifer, & Joanna, 807). It results due to the effect of global warming caused by increased levels of green house gases in the atmosphere. Green house gases include carbon dioxide, methane, and results in an increase of surface temperatures on earth. It is either human induced or natural and controlling it proves quite hectic. Climate change threatens many ecosystems such as grasslands, forests, aquatic, and mangroves. A picture of a mangrove trees ©G. Ellis/GLOBIO.org Conclusion Man contributes immensely in the causing climate change. For instance, deforestation and burning of fossil fuels increase the concentration of the green house gases in the atmosphere. High surface temperatures lead to altered weather patterns, soil warming, rise in seal level and thus influence both mangrove growth as well mortality (Valiela, Jennifer, & Joanna, 812). Soil warming contributes to enhanced soil respiration, methane, and sulphur release, root decomposition and peat decomposition. Sea level rise will cause the submergence of mangroves and thus threaten their existence. According to research findings, water use, and photosynthetic rates increase with an increase in carbon dioxide levels. Therefore, there is a need for restoration of oil impacted mangrove ecosystems. A lot of effort, use of modern technologies and resources need to be vested in such activity so that the entire mangrove ecosystem is not compromised but restored back to its former status before the human induced disturbance. More emphasis need to be put on ways of minimizing pollution, encouraging sustainable management, conservation and exploitation of the mangrove resources to curb extinction and ensure the resources become available to future generations. Consequently, more efforts need to be vested in sewage treatment and control of hydrocarbon and non-hydrocarbon pollution elements and thereby reducing the anthropogenic impacts on mangrove ecosystem. Mangrove reclamation needs to be discouraged and permits for such activities regulated to minimize human disturbances to the mangroves. Man must also regulate his activities, which contribute to production of green house gases and thus resulting to global warming and climate change. Consequently, since mangroves form part of important carbon sinks, there is a need for their protection and conservation so that carbon dioxide levels get controlled thus, reduce global warming and its resultant climate change. Richards & Bohnsack (1990) (Table 1) Works Cited Alfaro, Andrea C. "Effects Of Mangrove Removal On Benthic Communities And Sediment Characteristics At Mangawhai Harbour, Northern New Zealand." ICES Journal Of Marine Science / Journal Du Conseil 67.6 (2010): 1087-1104. Benson, Nsikak U., and Joseph P. Essien. "Petroleum Hydrocarbons Contamination Of Sediments And Accumulation In Tympanotonus Fuscatus Var. Radula From The Qua Iboe Mangrove Ecosystem, Nigeria." Current Science (00113891) 96.2 (2009): 238-244. Ellison, Aaron M. "Mangrove Restoration: Do We Know Enough?." Restoration Ecology 8.3 (2000): 219-229. Ghosh, Dipanjan. "Mangroves." Resonance: Journal Of Science Education 16.1 (2011): 47-60. Jess K. Zimmerman, Michael R. Willig, Lawrence R. 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