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Invasive plants are unfamiliar species that tend to spread out of control in their unnatural habitats.
The term “invasive” is generally a term reserved for plants that have been introduced from other regions and tend to flourish rapidly in their new habitats.
Invasive species encroach large areas of land, replacing existing natural vegetation and reducing native tree regeneration (David, 2019).
Characteristics of invasive plant
Invasive plant species are characterized by fast growth rates, short life-cycles, higher reproductive potential, high competitive abilities and allelopathy that make them successful invaders of native habitats. The main key characteristic of an invasive plant is that it is not indigenous to the area, and it tends to spread rapidly and overpower the local indigenous plants.
Invasive plants were introduced in the middle of the seventeenth century for a range of purposes that included timber, tannins, oils, firewood, ornamentals, stabilizing sand dunes, windbreak barriers, hedges, soil conservation and shade (Troup, 1932).
Threats caused by invasive plant species
Invasive alien plant species have threatened the integrity of ecosystems throughout the world. They affect not only the species diversity of native ecosystems but also threaten their biological integrity.
For instance, in India, there are numerous invasive species like Parthenium hysterophorus and Lantana camara which are very troublesome and have caused adverse ecological, economic and social impact (Early et., al. 2016).
Besides rapidly colonizing areas and replacing the native vegetation, it is also known to cause a number of human health problems, environmental degradation including threat to tourism activities, they cause fodder scarcity in addition to being unpalatable and some are toxic to livestock.
Invasive plant species which can be used as feed
Farmers have taken this issue as an opportunity. Most invasive species can be transformed as feed for livestock.
One of the most common invasive plant that is utilized as feed is the Prosopis, a genus of flowering plants in Fabaceae family that is found intruding all over the world. The fruits, leaves, flowers and tender twigs of the prosopis contain large amounts of protein and carbohydrates that are crucial for the animal growth.
Invasive plants are being crushed and converted into feed, since wood has a complex lignocellulosic biomass and consists of plant cell walls composed of lignin, and their cellulose and hemicellulose grow much taller than grass.
Naturally, ruminating animals do not eat such material unless they have an attraction to browse trees, bushes or shrubs during the early growth season, choosing to eat the fresh sprouts only.
Grass is also made up of lignin, cellulose and hemicellulose, however its structure is far less complex, this makes the degradation in the rumen of an animal much faster. Since grass has thin cell walls and leaf tissue, it results in higher forage quality.
To produce bush feed from prosopis, the crushing and milling is done when branches are young, fresh and ready for harvest. Younger bushes are less lignified and are more nutritious, hence their protein content is higher. Then supplements are added to the feed to make the fibres more digestible.
Invasive plant species pose a large threat to ecosystems, especially when no management practice is set in place to reduce the effect. But when a management approach such as pruning or harvesting of invasive plant species is in place, the relationship becomes a symbiotic one. The harvested materials can be transformed into feed for animals, providing a required and sufficient balance diet.
David, B., (2019). Definition of Invasive Plants: Invasive is not synonymous with aggressive.
Troup, R. S. (1932). Exotic forest trees in the British Empire (No. 634.947 T861). Clarendon Press.
Early, R., Bradley, B. A., Dukes, J. S., Lawler, J. J., Olden, J. D., Blumenthal, D. M., … & Sorte, C. J. (2016). Global threats from invasive alien species in the twenty-first century and national response capacities. Nature Communications, 7, 12485.
Le Houérou, H. N. (1978). The role of shrubs and trees in the management of natural grazing lands. In Position paper, item No10 Forest Congress, Jakarta. FAO. Rome.