Research Of The Farmland Plant Diversity In The Suburban Area Of Chongqing

Farmland plant community is the major component of the farmland ecosystems,and a high level of plant diversity guarantees the stability of such ecosystems.Farmland plant community is usually vulnerable,the maintenance of which often requires human intervention.Due to the rapid increase in the urbanization rate and the changes in traditional agricultural methods,it is of great importance to learn how changes in the structure and composition of farmland plant communities will affect the maintenance of farmland ecosystems and the traditional agriculture landscape.This study investigated the plant communities in the suburban area of Chongqing using two types of land-use gradients.The first type of gradient is comprised of the winter paddy field,seasonally impounded paddy field,and abandoned paddy fields(abandoned for 2,6,and 8 years,respectively),and the other type of which is comprised of arable land and abandoned arable lands(abandoned for 2,5 and 10 years,respectively).Specifically,the structure and composition of plant communities in different types of lands were examined,and then the change in plant diversity and the loss and turnover of species along the two land-use gradients were checked.This study is to provide the basic understanding of the farmland plant diversity and the conservation of traditional agriculture landscape in the suburban area of Chongqing.The major findings of this study are as follow:1)This study recorded 130 vascular plant species belonging to 49 families and 112 genera.Species of the family Compositae(24 species)and Gramineae(18 species)were the most abundant.Among all plant species investigated,the number of terrestrial annuals plants,terrestrial perennial plants,woody plants,aquatic annual plants and aquatic perennial plants accounted for 44.62%,36.15%,4.62%,8.46% and 6.15%,respectively.Dwarf growth form and high growth form plants accounted for 54.20% and 45.80%,respectively.2)Along the paddy field land-use gradient,the dominant species of the plant communities shifted from aquatic annual plants to terrestrial perennial plants and woody plants as the number of years of land abandonment increased.For the arable land gradients,the dominant species of the plant communities shifted from terrestrial annual plants to terrestrial perennial plants and woody plants as the number of years of land abandonment increased.3)Compositional similarity of the plant species was low between paddy fields and the abandoned paddy fields;calculated Jaccard similarity index for this type of lands ranged between 0.04 and 0.25.Compositional similarity of the plant species was high between the arable lands and the abandoned arable land;calculated Jaccard similarity index for this type of lands ranged between 0.20 and 0.67.4)After being abandoned for over 8 years,six representative paddy filed plant species were lost.Therefore,it is of higher priority to conserve the plant diversity in the agricultural lands such as the paddy fields investigated in this study.