Fantastic Flatworms and Where to Find Them: Insights into Intertidal Polyclad Flatworm Distribution in Southeastern Australian Boulder Beaches

Abstract

There is a rapid and extensive decline of our marine biodiversity due to human impacts. However, our ability to understand the extent of these effects is hindered by our lack of knowledge of the occurrence and ecology of some species groups. One such group of understudied organisms are marine flatworms of the order Polycladida, a conspicuous component of southeastern Australia’s marine ecosystems that has received little attention over the years. Intertidal boulder beaches support a diverse range of polyclad flatworms in other countries, but the role of these environments in maintaining biodiversity is not well understood. In this study, we identified hotspots of flatworm occurrence by assessing the diversity and overall abundance of flatworms at boulder beaches along the southeast Australian coast. Bottle and Glass, Sydney Harbour, was found to be the most diverse site for flatworms. We also identified a higher occurrence of flatworms under large boulders and less exposed beaches and noted an increased presence of flatworms at higher latitudes. Probable influences on these patterns such as the requirement for shelter and protection are discussed. This study contributes to our knowledge of Australia’s coastal biodiversity and can be used to assist in the management and conservation of our marine environments.

Negative Evidence for Sex-Linked Heteroplasmy in the Nemertean Worm Notospermus geniculatus (Delle Chiaje, 1822)

“…Marine biodiversity is extensively declining due to human pressures and impacts [1]; however, understanding the extension and consequences of these multiple impacts is difficult since we still have limited scientific knowledge regarding some marine taxa [1]. Therefore, adding to the knowledge on the biology and ecology of a broad spectrum of marine species is of primary importance to investigate their extraordinary biodiversity and to understand their complex evolutionary patterns before it is too late.…”

Marine Nearshore Biodiversity: Introduction to the Special Issue

“…Long-term monitoring of subtidal benthos like that associated with kelp forests, globally threatened by climate change [10], can use this approach for cost-effective surveys and reporting. [2], [4], [6], [7], [9], [11], [12], [13], [14], [15], [16].…”

“…Worldwide, marine flatworms, i.e., polyclads, present a prime example of this situation, where the dearth of basic ecological knowledge for this taxonomically challenging group, like habitat preferences, seriously hinders an accurate evaluation of species occurrence and richness. Tosetto et al [12] tackle this problem in surveys of intertidal boulder beaches in southeastern Australia and report distribution patterns related to beach exposure, boulder and latitude. Their work constitutes one of the few studies of this kind for marine polyclads and will stimulate more investigations of these understudied predators.…”

“…Nearshore study areas investigated by authors published in this Special Issue. Symbol and reference: [2], [4],[6],[7],[9],[11],[12],[13],[14],[15],[16].…”