Herbicides use and Impact on Species loss on the Environment
Matthew Emberga- Biem
ebiemmatthew@gmail.com
Herbicides are a broad class of chemical substances that are toxic to plants and are used to remove nuisance plants such as grasses and weeds that may compromise the growth and yield of desired crops that are in close proximity. Herbicides constitute a special class of toxic substances to plants ranging from broad spectrum; selective; contact; systemic; and residual herbicides. In agricultural use, herbicides are also classified as pesticides; hence weeds and grasses constitute pests of crop plants too.
With the increasing demand for food and commercial agriculture, the use of herbicides to control stubborn pests has increased in recent times with the attendant effects on the survival of organisms in environments where they are used. Thus, herbicides are used in agricultural and wild ecosystems to reduce the density of weeds and promote the growth of desirable plant species. The use of herbicides in agro-ecosystems may change the composition of weed populations, sometimes permanently. For instance, broad spectrum herbicides reduce food sources for birds and mammals. This can produce a substantial decline in rare species populations.
By changing vegetation structure, herbicides can render habitat unsuitable for certain species. This threatens insects, farmland birds, mammals as well as soil fauna, and could have a lasting impact on the ecosystem long after the stoppage of agricultural activities in such an area. It is noteworthy to state that, although herbicides are among the most effective and resource efficient tools to treat invasion of farms by weeds, their continuous use may lead to a gradual proliferation of pesticide resistant species that aggressively colonize the ecosystem at the expense of other lost species: perpetuating their kind in an aggressive act such that other plants find it difficult to re-grow and may be permanently lost from the environment. These invasive species of plants out-compete others and ensure their continued presence and may become secondary colonizers in adjacent areas, thus taking up the vacuum left by the lost species. These new plants effectively replace the known indigenous plants and hence create a unique ecotype.
Ecotypes created as a result of the continuous use of herbicides lead to a sharp decrease in species diversity and consequently the absence of species richness (the availability of different organisms in equal composition in an area) in the ecosystem.
Furthermore, herbicide use may lead to complete extinction of plants and animals that have for ages been indigenous to specific areas, which may be of use to man in terms of medicinal plants (herbs), needed soil microbes, and game for food. Species loss from the environment as result of herbicides use is usually accompanied by habitat disappearance for animals and soil fauna.
Conclusively, herbicide use has greater effects on species loss in any given ecosystem, even when such usage is within the limits approved by government environmental protection agencies; such that their continuous use is not encouraged due to the fact that a good number of herbicides are also harmful to the handlers and do not readily degrade within the environment. To this end, the writer suggests that the government through research organizations should outline regulations on the use of herbicides with respect to their lasting effects on the environment and man. Additionally, the possibility of use of organic herbicides which are readily biodegradable should also be considered.
