Seasonal changes on macroalgae community structure on the South Coast of Yogyakarta, Indonesia

<p style="-webkit-text-size-adjust:auto;-webkit-text-stroke-width:0px;caret-color:rgb(0, 0, 0);color:rgb(0, 0, 0);font-family:"Times New Roman", serif;font-size:medium;font-style:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;line-height:32px;margin:0cm 0.1pt 0cm 0cm;orphans:auto;text-align:justify;text-decoration:none;text-indent:0px;text-transform:none;white-space:normal;widows:auto;word-spacing:0px;"><span style="color:rgb(63, 63, 63);font-size:10pt;line-height:26.666664px;" lang="EN-US">The environmental conditions significantly influence the dynamics of macroalgae community structure and distribution</span><span style="color:black;font-size:10pt;line-height:26.666664px;" lang="EN-US">. This study investigates the effects of seasonal changes on the macroalgae community structure and distribution along the South Coast of Yogyakarta. The study was conducted over twelve months in two intertidal zones, Trenggole and Nguyahan, using the transect method with plots. Monthly rainfall data and water quality parameters were collected as supporting data. The data were analyzed using ANOVA, and the relationship between water quality and community structure was determined using Canonical Component Analysis (CCA). The results indicated a moderate diversity index (1.05-2.71) and a low dominance index (0.02-0.37). The average abundance at Trenggole (145.74 ind. m<sup>-2</sup>) was higher than at Nguyahan (103.72 ind. m<sup>-2</sup>). The percentage coverage at Trenggole (67.71%) was lower than at Nguyahan (88.14%). </span><span style="font-size:10pt;line-height:26.666664px;" lang="EN-US">Seaweed abundance and percentage cover were relatively higher during the wet season than in the dry season</span><span style="color:black;font-size:10pt;line-height:26.666664px;" lang="EN-US">. The diversity of macroalgae tended to be higher in the rainy season than in the dry season. Seasonal changes significantly affected macroalgae abundance and coverage at Trenggole, whereas at Nguyahan, the distance from the shoreline showed significant differences. Temperature, salinity, and pH were the most influential factors affecting the macroalgae community structure. Additionally, coastal characteristics, distance from the shoreline, and substrate types played a pivotal role in shaping the macroalgae community structure. Rhodophyceae species were the most dominant, followed by Chlorophyceae and Phaeophyceae, on the South Coast of Yogyakarta. </span></p>