Since the mid-sixties of the last century, monoculture farming, a cultivation method only one species of a crop at a time has quickly achieved popularity in Bangladesh due to obtaining profit maximization from cultivated lands. Simple cultivation, managing and harvesting systems, specialized production, technological advances, high efficiency, higher earnings are the major advantages for the monoculture farming movement. Nonetheless, soil quality degradation, vulnerable to rapid widespread outbreaks of diseases and pests, declining biodiversity, environment degradation and climate change is the dominant causes against the monoculture farming system. Likewise, this cultivation practice may lead to the extinction or relocation of entire species in certain areas. Hence, it can be said that monoculture farming has significant negative drawbacks with the potential to cause irreversible damage to the ecological system.

In monoculture plantations, “The numbers of bird species in Teak (Tectona grandis L.f.; Segun in Bengali) plantations of Mizoram were almost half of those found in rainforests of the state remarked by the American Ornithological Society. Also, Larry Lohmann of the Corner House states “Teak makes the soil hard and the toxins in its leaves have more severe effects on other species. The larger the monoculture plantations, the worse the environmental effects,” In Bangladesh, native species of plants in most Village Common Forests are the natural and effective controllers for natural watershed management. On the contrary, local people expressed their opinion that the waterfalls of Chittagong Hill Tracts (CHT) near to Teak plantations show completely out of water in the dry season and their water service is not enough even in peak season.
Tobacco, Nicotiana tabacum, a non-indigenous species grown as a mono-crop. Its cultivation adversely affects biodiversity. Many of the farmers of CHT have been losing their interest in cultivating indigenous crops like paddy, banana, maize, sesame, cotton, potato, pumpkin etc. as they became defaulters of loans provided by tobacco companies. To control the tobacco pests, not only are tobacco growers at risk from exposure and storing of the pesticides during the application but also the chemicals that leach into soil and find their way into aquatic bodies and contaminate the food chain. Furthermore, more significant species of flora and fauna are affected seriously alike to extinct regularly. A survey of the tobacco field at Kishoreganj Upazila in Nilphamari district reveals that Ipomoea aquatic spinach (Kolmi shak) and Sessile joyweed (Shalonchi shak) are not available presently. Also, indigenous birds, fishes, forest animals in on the way of extinction in that the study area (Ali et al. 2015). The farmers Nilphamari are not paying heed to Agriculture officers as tobacco cultivation brings them huge profits every year (Sarker 2020).

In monoculture of invasive species like Tilapia (Oreochromis spp.) and other carp species is a threat to local native fish species biodiversity and ecosystem (Islam and Yasmin 2017). Tilapia is an omnivore and it has a high potential of transmission to the natural water resources. Tilapia is a factor of imparting disease to other aquatic species. Tilapia has potentially detrimental long-chain fatty acids of omega 6 and it may cause heart diseases of humans. Tilapia was introduced to Bangladesh from Thailand in 1954. Now Tilapia is ranked 6th in terms of pond fish production accounting 8.1% of total aquaculture yield. Tilapia is commonly found in all most all aquatic bodies including Kaptai Lake of the country.
Slash-and-burn agriculture locally called Jhum chash is a subsistence food production system for ethnic minorities in CHT. This type of cultivation causes 100-250 metric tons of topsoil erosion per hectare per year. Also, this cultivation practice is jeopardy for forest productivity, biodiversity and socio-economic conditions of local people (Karim and Mansor, 2011). Recently different mono-cropping of Turmeric, Zinger, Aroids, Maize, and some foreign fruit species’ plantations have been introduced that might result in unsustainable agriculture and imbalance ecological situation in CHT.
The herbicide is being used to kill the unwanted plant. The Indiscriminate use of chemical weed killers causes damage to the biodiversity particularly the killing of beneficial arthropods including soil microorganisms, enter the human food chain and environment including water supply. The global herbicide market was $23.97 billion in 2016 and is estimated to reach $34.10 billion by 2022 (Dublin 2017). Likewise, in recent years, chemical weed control has increased in the entire country. The American Journal of Tropical Medicine and Hygiene linked the sudden deaths of 13 children in Dinajpur in 2012 to chemicals sprayed on lychee trees (Moneruzzaman 2020). A maximum number of aged cultivators of ethnic communities in CHT accused chemical herbicides of endogenous crop verities as well as species loss in some cases.  Apart from herbicides, excess and unprotected use of molluscicides, rodenticides, fungicides, insecticides and paradoxically in other synthetic agrochemicals have a great negative impact on the environment, species diversity and health as well.

More than 5000 floral species of which about 300 species are being regularly cultivated in Bangladesh and approximately 300 wild indigenous species of plants have been recognized that are relatives to the cultivated crops grown. The insects are known to be the most successful and diverse animals on the earth. They are considerably estimated to comprise more than 75 percent of the known species of the animals. In addition, at least four times more insect species worldwide are still unrecorded. They are important because of their ecological role, and influence on agriculture, human health, and natural resources as pollinators, pests, disease carriers or vectors, natural enemies, bio-indicators etc. Bangladesh has a transitional zone of flora and fauna, because of its geographical settings and climatic characteristics. At least 103 flower-visiting insect pollinators like bees, flies, butterflies and beetles have been recorded from 44 economic plants. Since half-century, native pollinators face many threats, and unplanned urbanization, habitat, destruction, monoculture farming, pests, diseases, invasive species introduction, inappropriate use of agrochemicals and climate change are the major causes for leading to declines in diversity. More specifically in monoculture farming, there is a recognized link between monoculture landscapes and fewer wild pollinators and natural enemies. Likewise, this condition may observe in other contributions of insects. Under a supporting research project of the Centre for Biodiversity Genomics, University of Guelph, Guelph, Ontario, Canada a total number of 317 species, 447 genera, 227 subfamilies, 274 families belonging to 23 orders of agro-arthropods from Bangladesh have been confirmed through DNA barcoding technique.

In brief, the increasing trends in monoculture farming along with the diversity of modern varieties lead to the gradual reduction of traditional varieties. Consequently, it negatively affects existing ecosystem and accelerates the worse environmental effects. It is high time carried out more specific researches for sustainable management of species diversity and environment. Integrated farming systems with bio-management are highly efficient for a viable economy, biodiversity and environmental benefits.
Previous Post Next Post