A Preliminary Floristic Survey of the Benthic Marine Algae of Rotuma Island

A preliminary study of the intertidal benthic macroalgal flora of the island of Rotuma (12°30'S 177°05'E; politically attached to the Fiji Island group) has revealed a total of 88 taxa, including 41 Rhodophyceae, 11 Phaeophyceae and 36 Chlorophyceae, representing the first published records of marine algae for this island. Of these, 30 represent new records for the Fijian flora. The Rotuman flora is distinct from that of Fiji, a probable consequence of habitat limitations and high exposure regimes on Rotuman reefs that have led to a predominance of low-profile, robust algal species. A distinct north-south distribution pattern was found, brought about by variations in exposure regimes. Biogeographic considerations further dissociated the Rotuman and Fijian floras, the former being more equatorial and in the path of oceanic currents dispersing algal species from donor areas in the central and western Pacific.针对罗图马岛（12°30'S 177°05'E；行政上隶属于斐济群岛）潮间带底栖大型藻类区系开展的初步研究，共记录到88个分类单元，其中红藻门（Rhodophyceae）41种、褐藻门（Phaeophyceae）11种、绿藻门（Chlorophyceae）36种，这是该岛屿海洋藻类的首次正式发表记录。其中30个类群为斐济藻类区系的新分布记录。罗图马岛的藻类区系与斐济本土区系存在显著差异，这一差异大概率源于罗图马礁盘的生境限制与高暴露环境，使得该区域以低矮健壮的藻类物种为主导。研究同时发现，该岛藻类区系呈现明显的南北分布格局，这一格局由暴露环境的差异所塑造。从生物地理学视角进一步分析可知，罗图马与斐济的藻类区系彼此分化：罗图马岛更接近赤道，且处于源自中太平洋与西太平洋物种源区的藻类传播洋流路径之上。