(a) whether the Government has assessed the effects of overgrowth of lantana, parthenium and other foreign weeds on forests and grasslands in the country and if so, the details thereof;
(b) whether the overgrowth of lantana, parthenium and other foreign weeds have adverse effects on the lives of herbivores like deer and consequently on the top order of the food chain like tigers and leopards; and
(c) if so, the details thereof ?
MINISTER OF STATE (INDEPENDENT CHARGE) FOR ENVIRONMENT, FOREST AND CLIMATE CHANGE
(SHRI PRAKASH JAVADEKAR)
(a) The Government is aware of the threats posed by Invasive Alien Species such as Lantana, Parthenium, Cuscuta etc on ecosystems and biodiversity of the country. In the National Biodiversity Action Plan approved by the Union Cabinet on 6th November, 2008, biological invasions by exotic species have been discussed as one of the major factors leading to loss of biodiversity in the country. In terms of the extent of distribution, Lantana is perhaps one of the most important invasive species in forest ecosystems of India. Indian Council of Forestry Research and Education, Dehradun, as a part of its exercise to re-evaluate the forest types of India, observed that Lantana and Parthenium affected regeneration of Teak.
(b) & (c) There are no conclusive studies in this regard. However, invasive species viz. Lantana and Parthenium replace other native plant species and grasses by adversely affecting their regeneration and growth due to allelopathy effect, resulting in reduced biodiversity and availability of food base of wild herbivores like deer and other ungulates. Herbivores are considered as the primary consumer of the food chains, at the top of which are tiger and other large carnivores. Therefore, decline in the population of mammalian herbivores has the potential to impact tigers and other large carnivores which are critically dependent on herbivores as prey base.
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