Occurrence and Distribution of C 4 Plants under Diverse Agricultural Field Types in Korea

Abstract

In order to search for distribution characteristics on C4 plants at the paddy fields, uplands, orchard and roadside in South Korea, vascular plants were investigated. Flora investigation had been carried out from May 2002 to October 2006 at 241 plots. In the results of survey, the flora of these areas consist of 74 families, 231 genera and 352 species totally. The class frequencies were arranged by the order of Magnoliopsidae (255 species), Monocotyledoneae (89 species), Pteropsida (7 species) and Sphenopsida (1 species). The number of species in each investigated agricultural field types was 55 families with 203 species in paddy field, 49 families with 218 species in uplands, 44 families with 115 species in orchard and 48 families with 202 species in roadside respectiviely. Representative species compositions of these four agricultural field types were characterized by Artemisia princeps, Persicaria thunbergii in paddy field, Artemisia princeps, Erigeron annuus in upland and roadside, Commelina communis, Digitaria ciliaris in orchard, respectively. Therefore, indicative species in agricultural ecosystem was Artemisia princeps. Among the investigated 352 species, C4 plants identified were 38 species, and the occurrence ratio of C4 monocotyledonous plants were higher in paddy field, orchard and roadside than upland. Such differences in the occurrence ratio of C4 plants under diverse agricultural field types reflect differences in environmental condition such as micro-climate, soil moisture under various agricultural fields. Dominant C4 monocotyledonous plants were Digitaria ciliaris and Commelina communis, while C4 dicotyledonous plants were Amaranthus mangostanus and Chenopodium album var. centrorubrum in agricultural fields. Naturalized plants were identified as 47 species and occurrence ratio were higher in upland and roadside than other agricultural field types. Among the investigated naturalized plants, C4 plants were Amaranthus mangostanus and Amaranthus retroflexus. Distribution characteristics of representative C4 plants in agricultural field types, revealed that the projected increase in temperature due to climate change may provide better conditions for the growth of C4 plants. Thus, the necessity of long-term monitoring should be conducted on the diffusion of C4 plants that may threaten influence agroecosystem in Korea.