The Visitation Aspect and Habitat Preference of Plover (Pluvialis spp.) in the Nakdong Estuary

The study is performed in the Nakdong Estuary located in the city of Busan. The study focuses on understanding the visitation aspect of plover (Pluvialis spp.) and their habitat preference through long-term monitoring in the Nakdong estuary where nearby environment rapidly changes based on comparison and analysis of data from early 1990s and mid-2000s. Among the total of 6,672 individuals in 3 genus and 10 species during the survey, the number of Pluvialis spp. was 910 (13.64%) for 2 species including 57 Pacific Golden Plover (Pluvialis dominica) and 853 Grey Plover (Pluvialis squatarola). Among 295 of 910 individuals, 2 genuses of Pluvialis discovered in the first half of 1990s, the number of Pacific Golden Plover (Pluvialis dominica) and Grey Plover (Pluvialis squatarola) is 41 and 254, respectively. 615 individuals discovered in mid-2000s consist of 16 Pacific Golden Plover (Pluvialis dominica) and 599 Grey Plover (Pluvialis squantarola). The number of individuals recorded per month for the 2 periods show no significant difference (P=0.522) and the number of individuals in the mid-2000s (Mean=102.50) is larger than that of early-1990s (Mean=73.75). Visitation aspect per month states that the number of individuals in August was the highest of 369, followed by 168 in April, 120 in May, 63 in September and 55 in October, respectively. The average number of individuals for the 5 regions visitation number showed 26.74 including 69.33 in DMD, 18.50 in JJ and SJD, 9.17 in SJ and DY and 6.88 in LUD, showing significant differences among regions (P=0.027). DMD showed the highest number of individuals (Mean=69.33) and LUD recorded the lowest (Mean=6.60) and there was no individual in USD. Regional visitation number showed that the total of 615 individuals have been discovered for 6 years and 416, 111, 55 and 33 individuals in DMD, JJ and SJD, SJ and DY and LUD, respectively. Monthly recorded individuals stated that DMD had 218 individuals in August, 105 in April and 45 in May of 416 in DMD and 42 in August and 22 in September of 111 in JJ and SJD. The results showed that the number of plovers here was not fluctuated much in the early 1990s and mid-2000s despite many environmental changes in the Nakdong Estuary, and there was regional difference among JJ, SD, SJ and DYD, showing preference difference. Future researches will be required whether these results show that the places are still good for habitat of migrant birds or they have no other choices.