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   Ageratum conyzoides (herb)
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    Details of this species in Doon Valley
    Status: Alien
    Invasiveness: Invasive
    Occurrence: Established
    Source: Negi & Hajra 2007
    Arrival Date:
    Introduction:
    Species Notes for this Location:
    Management Notes for this Location:
    Location Notes:
    Indigenous flora of the Doon Valley in Northwest Himalaya in the Indian subcontinent, have been subjected to dramatic alteration due to the deliberate and incidental introduction of alien species from various parts of the world. Since the Doon Valley is part of the Himalayan ‘hotspot’ belt, globally designated for priority of conservational activities in India, the occurrence of 45.69% woody and 19.4% herbaceous alien species and the naturalization of some of them cannot be considered safe for native and endemic flora from an ecological and socio-economic perspective. Most of the introduced herbaceous and shrubby taxa multiply in a limited period of time and destroy the endemic and native flora.

    Geographically, the Doon Valley lies between lat. 30䢨’N and 30䣆’N and long. 77䣌’E and 8䢺’E, covering an area of about 2244.78 kilometers squared. The mean annual temperature of the valley during the last 42 years (1961– 2002) is 19.62ºC, while the average annual rainfall is 1950.24 mm (P. S. Negi, unpublished, in Negi & Hajra 2007). The temperature ranges from a minimum of –2.4ºC in January to a maximum of 43.8ºC in June. The relative humidity is well over 50%, except during May and June. The soil is generally medium loam, overlying boulder deposits of great depth. Within the valley, the elevation ranges between 315 and 1000 meters, while the northern ranges show elevations of up to 2500 meters. Botanically, the Doon Valley is of great interest because it has suitable climatic conditions for both temperate and tropical aliens and therefore, many exotics are established permanently.

    Impacts:
    Modification of fire regime: A. conyzoides introduced from tropical America has expanded at an alarming rate, especially in agricultural fields, along footpaths, road sides and in gardens of heavy peat content. Its dominance in fire-burn areas makes it appear a permanent denizen of India.
    Other: It creates allergic problems.
    Reduction in native biodiversity: It is harmful to native floristic composition.
    Last Modified: 27/11/2009 12:08:14 p.m.


ISSG Landcare Research NBII IUCN University of Auckland