Jilmoe Moor, a montane peatland found in Mt. Odae National Park, Korea, has been influenced by a surrounding pasture-land for more than 30 years. Here, we used multivariate analyses to study the vegetation structure at that Moor. Four distinct communities were consistently separated (82.2% of the total variance): two wetland communities -- Sphagnum palustre (SP) and Persicaria nepalensis - Persicaria thunbergii (PNPT). In addition, we recorded two invaded upland communities: Phleum pratense (PP) and Festuca ovina - Artemisia feddei (FOAF). Of those pasture species, timothy (Phleum pratense) was most dominant in all wetland communities except SP. Our data demonstrate that the pasture has affected the settlement and expansion of two pasture communities on the moor by acting as a propagule source and also through the input of nutrients in the form of fertilizer and waste from cattle. Moreover, this enrichment of the moor habitat may have facilitated replacement of the original wetland community. That is, its unusually high levels of phosphorus and potassium may have resulted in the dominance of Persicaria nepalensis, and P. thunbergii, which often occur on nutrient-rich sites. Therefore, proper policies should be enacted to restore Jilmoe Moor as a montane peatland by eliminating the effect of the surrounding pasture.