Preliminary survey of exotic invasive plants in some western and high plateau mountains in Yemen

ABSTRACT

Yemen Is the richest country in the Arabian Peninsula in Its biodiversity at all levels; genes, species, ecosystems and traditional knowledge. It is believed that the two serious threats to biodiversity are habitat destruction and nonnative species invasion in any ecosystem. Inspite of the observed threats of exotic invasive plant species In Yemen, these plants continue to be unchecked and unmonitored. The objective of study is to provide information and accurate identification of the most abundant exotic invasive plant species. Pilot survey of these plant species was carried out mainly in mountainous areas which is the most fragile ecosystems. Interviews with local people for primary assessment of the invasive plant species impact were also made, in addition to primary field observations. The results indicated that new invasive plant species were recorded in the country, although they are very abundant at this time, parthenium hysterophorus was recorded for the first time in hillsides In Hajah. Parthenium hysterophorus is sensitizer causes many health problems to human and animals, it also strong allelopathic weed. This weed in addition to the unpalatable and allelopathic Tagetes minuta has replaced native grazing vegetation in escarpment and the last has also invested the wastelands, roadsides, grazing lands, and abandoned fields even at above elevation of 3000 m. Tagetes minuta has led to reduction in population of Acacia asak trees and other species in the invasion areas. Opuntia dillenii was found at Bura mountains at the core of the protected area, its very serious threat to biodiversity and it causes blindness to animals and human whom get in contact with it. Other species were moving from the valleys upward in way to Bura mountains like prosopis sp., on the other hand, new Invasive species of nicotiania glauca was recorded In mountains surrounding Sana'a city. The distribution of some of the most abundant Invasive plant species and their observed impact will be presented in this paper