An investigation of the monitoring and management of the habitat of the family Ardeidae in Muan Yongwol-ri Breeding Sites in Korea

Abstract

The purpose of this study was to investigate the variation in populations and species of the family Ardeidae through an evaluation of environmental habitat characteristics in the breeding sites of the family Ardeidae in Muan Yongwol, Korea. The study area has been protected as a Natural Monument (No. 211) in Korea and is located in Yongwol, Muan, in Korea. The monitoring of the herons was performed in October 2015 and from February to September 2016. The monitoring of vegetation, fish, benthic macroinvertebrates, and amphibian was performed in April and July of 2016, and the monitoring of land insecta was conducted in July 2016. The populations of the Ardeidae family in the Muan Yongwol-ri habitat of egrets and herons were recorded as 840, 1155, 1211, and 52 for Ardea cinerea, Egretta alba, Egretta garzetta, and Nycticorax nycticorax, respectively. Bubulcus ibis was not found. Terrestrial insects were found in 10 orders, 62 families, and 142 species. Benthic macroinvertebrates were in 11 orders, 15 families, and 18 species, and the predominant species was Chironomidae sp. Fish were found in two orders, three families, and nine species, and Carassius auratus were dominant. The proportions of fish, amphibian, reptilia, insecta, and others for food of Ardeidae were observed at 56.9%, 20.2%, 6.4%, 14.7%, and 1.8%, respectively. The area of the nest trees of Ardeidae family was approximately 8805 m2. The nest tree counts of Pinus thunbergii, Quercus serrata, and Quercus acutissima in the breeding sites were 147, 3, and 3, respectively, and all dead trees were Pinus thunbergii. The levels of salinity and available phosphate were much higher in the breeding site of the Ardeidae family than they were in control area. A management plan should be followed in this breeding area, such as understory vegetation thinning, soil improvement, or transplanting nest trees.