바다숲 상태 및 군집 구조 평가를 위한 생태학적 모델 개발

Abstract

This study sought to develop a method for the characterization of natural marine algal community sites and marine afforestation sites using quantitative criteria for the classification of terrestrial vegetation. Additionally, algal biomass estimation methods were also assessed to enable non-destructive analyses of marine algal communities and for utilization in ecological studies. The survey was conducted on a total of 31 natural marine algal community sites and 13 marine afforestation sites from 2017 to 2019. During the study period, a total of 319 species (including 32 Chlorophyta, 58 Phaeophyta, and 229 Rhodophyta) were identified in all surveyed areas. By coast, 199 species were identified in the East coast, 184 species in the South coast, 231 species in the Jeju Island coast, and 214 species in marine afforestation sites. The proportion of taxa over the entire coast ranged from 6.0 to 11.2% for Chlorophyta, 17.8 to 19.6% for Phaeophyta, and 70.7 to 74.4% for Rhodophyta, exhibiting similar proportions in all sites. The mean biomass in all study sites was 1,203.46 g/㎡ (including 34.12 g/㎡ Chlorophyta, 911.26 g/㎡ Phaeophyta, and 258.08 g/㎡ Rhodophyta). The East coast exhibited a biomass of 681.93 g/㎡, with 1,443.7 g/㎡ in the South coast, 1,563.73 g/㎡ in the Jeju Island coast, and 1,124.48 g/㎡ in marine afforestation sites. The biomass ratio of taxa over the entire coast ranged from 1.0 to 3.3% of green algae, 67.6 to 88.8% of brown algae, and 7.8 to 31.4% of red algae, with few differences between coasts. In the case of marine afforestation sites, the number of species and biomass at each point were different depending on the sites. Compared with previous studies, the number of species was generally similar in all sites (East Sea, South Sea, and Jeju coast) and the mean biomass was half in the East Sea and the Jeju coast, and 1.2 times higher in the South Sea coast than in the past. Compared to previous studies conducted on the East coast, the number of species in the marine afforestation sites was relatively high, and the biomass was similar. To evaluate the status of marine algal communities, I divised a community evaluation method using the types of marine algae (CEMA), and the EEI-c model (a method for community status evaluation based on the coverage of each functional marine algal group) was also used for comparison. The EEI-c model did not reflect the actual status of the algal communities (i.e., it rendered considerably inaccurate estimations and even contradictory results), and therefore it was not possible to explain the difference in community characteristics between each site. In contrast, the CEMA method accurately reproduced, the overall coverage of marine algae and the dominance of each type, and the community status was more clearly distinguished than in the EEI-c model. Therefore, the CEMA method was deemed appropriate for community status evaluation. To take advantage of marine algal ecological studies and conduct non-destructive assessments, a formula (Y = aX) to estimate marine algal biomass was developed. Quantitative data (including coverage, wet weight, and dry weight) were measured by species, and the relationship between cover and wet weight was based on 7,747 data points, whereas the relationship between wet and dry weight was based on 3,441 data points. Regression analysis was performed when there were more than 5 data points by species. The results of the relational formula (Y = Fresh weight, X = Coverage) for estimating the fresh weight from the coverage of marine algae are detailed below. Ecklonia cava, Y = 30.92 X (N = 368, R2 = 0.884); Gelidium elegans, Y = 13.69 X (N = 359, R2 = 0.958); Plocamium telfairiae, Y = 13.68 X (N = 345, R2 = 0.944); Rhodymenia intricata, Y = 5.87 x (N = 317, R2 = 0.963); Corallina pilulifera, is Y = 7.13 x (N = 299, R2 = 0.912). Species with high dry weight to coverage ratio included kelp species such as Ecklonia cava, E. stolonifera, Eisenia bicyclis, and Sargassum spp., whereas species with low wet weight to coverage ratio were mostly small algae. The results of the relational formula (Y = Dry weight, X = Fresh weight) for estimating the dry weight from the fresh weight of marine algae are detailed below. Ecklonia cava, Y = 0.14 X (N = 187, R2 = 0.942); Rhodymenia intricata, Y = 0.19 X (N = 155, R2 = 0.902); Sargassum horneri, Y = 0.10 X (N = 109, R2 = 0.992); Corallina pilulifera, Y = 0.39 X (N = 96, R2 = 0.967);