The Use of Multivariate, Graphical Methods, and Feeding Types of Macrobenthic Structure in Assessing Environmental Disturbance: Temperate versus Tropical Regions

Abstract

Introduction and Objective This study is aimed to assess the effectiveness of multivariate analyses and distributional/ graphical techniques in assessing the response of macrobenthic assemblages to environmental disturbance caused by fish farming, comparing temperate and tropical regions. Methods The biotic datas were used from samples taken under southern blue-fin tuna farms in southern Spencer Gulf, South Australia, and under floating net cage at Rawapening Lake, and under fish impoundment at coastal region of Demak District, Central Java, Indonesia. Principal Component Analysis (PCA) and Non Metric Multi-Dimensional Scaling (NMDS) were used for analysis the abiotic and biotic datas, respectively. Abundance-Biomass Comparison (ABC) curves were employed to detect the level of disturbance. Results The results showed that the use of multivariate analyses and distributional/graphical techniques are effective to assess the severity of disturbance, owing to sensitive response of macrobenthic assemblages to environmental disturbance that made it possible to detect effects of farming activities. The ordination of MDS and ABC curves showed consistently with Wstatistic and H’ index values in assessing the status of the area in that both tropical and temperate regions. They clearly separated the disturbed and undisturbed areas, whether in spatial and temporal, thus the methods may be applied at temperate and tropical regions. Conclusion Seasonal fluctuations caused by natural variability, hydrodynamic conditions, sediment characteristics, and organic matter are likely to be responsible for the observed changes of the assemblages over the study period. The use of multivariate analyses and distributional/graphical techniques are effective to assess the severity of disturbance, owing to sensitive response of macrobenthic assemblages to environmental disturbance that made it possible to detect effects of farming activities.