This study presents the first Korean records of two subtropical fish species, Pseudojuloides paradiseus and Diplogrammus xenicus, collected around Jeju-do Island, as well as one boreal fish species, Erilepis zonifer, collected in Busan (approximately 200 km away from Jeju-do Island). In this study, we discuss the implications of the species’ habitat range expansion. Previously, P. paradiseus was known as an endemic species of Japan, while D. xenicus was known to inhabit the Eastern Indian Ocean and the Pacific Ocean excluding around the equator, and E. zonifer was only known to inhabit the Pacific Ocean between eastern Japan and the western USA. Their habitat range expansions might be attributed to the expansion of the Tsushima Warm Current at the surface layer and/or the North Korean Cold Current at the bottom layer. Our findings may suggest that habitat of marine fish is being changed continuously by climate change or oceanic currents. Therefore, it needs to conduct integrated and systematic monitoring of fish fauna to response changing marine biodiversity.

Recent losses of seagrass beds have resulted in a decrease in seagrass-associated fishes, highlighting the need for the improved management of such habitats and resources. Analyses of feeding patterns of fish associated with seagrass habitats are useful for understanding their habitat dependence, which contributes to achieving their effective conservation. The gut contents of 61 fish species were examined to clarify the food habits of subtropical seagrass fishes in Nagura Bay, Ishigaki Island, southern Japan. A cluster analysis based on dietary overlaps showed that the seagrass fish assemblage comprised six trophic groups (small crustacean, large crustacean, detritus, plant, fish and zooplankton feeders). Small and large crustacean feeders were the most abundant, followed by detritus, plant and fish feeders. Zooplankton feeders were represented by only two species. Ontogenetic changes in food preference were recognized in four species, including Lutjanus fulviflamma, Ostorhinchus ishigakiensis, Gerres oyena and Siganus fuscescens. Small individuals of the four species generally fed on small crustaceans or detritus, subsequently switching to other larger prey items with growth (e.g. crabs, shrimps and seagrass fronds). The most important food items for the assemblage comprised harpacticoid copepods, shrimps, crabs and detritus, representing high cumulative gut volumes for all fishes. Some species showed diets remarkably different from those determined for fishes in other seagrass beds off a nearby neighbouring island, evidence of the food-use patterns of seagrass fishes varying on a small spatial scale. Such dietary flexibility may increase the adaptability of fishes to seagrass beds characterized by significant variations in available food resources.

Debate about the nature of climate and the magnitude of ecological change across Australia during the last glacial maximum (LGM; 26.5–19 ka) persists despite considerable research into the late Pleistocene. This is partly due to a lack of detailed paleoenvironmental records and reliable chronological frameworks. Geochemical and geochronological analyses of a 60 ka sedimentary record from Brown Lake, subtropical Queensland, are presented and considered in the context of climate-controlled environmental change. Optically stimulated luminescence dating of dune crests adjacent to prominent wetlands across North Stradbroke Island (Minjerribah) returned a mean age of 119.9 ± 10.6 ka; indicating relative dune stability soon after formation in Marine Isotope Stage 5. Synthesis of wetland sediment geochemistry across the island was used to identify dust accumulation and applied as an aridification proxy over the last glacial-interglacial cycle. A positive trend of dust deposition from ca. 50 ka was found with highest influx occurring leading into the LGM. Complexities of comparing sedimentary records and the need for robust age models are highlighted with local variation influencing the accumulation of exogenic material. An inter-site comparison suggests enhanced moisture stress regionally during the last glaciation and throughout the LGM, returning to a more positive moisture balance ca. 8 ka.

Branched glycerol dialkyl glycerol tetraether (GDGT) distributions observed in a sediment core from Lake McKenzie were utilized to quantitatively reconstruct the pattern of mean annual air temperature (MAAT) from coastal subtropical eastern Australia between 37 and 18.3 cal ka BP and 14.0 cal ka BP to present. Both the reconstructed trend and amplitude of MAAT changes from the top of the sediment core were nearly identical to a local instrumental MAAT record from Fraser Island, providing confidence that in this sediment core branched GDGTs could be used to produce a quantitative record of past MAAT. The reconstructed trend of MAAT during 37 to 18.3 cal ka BP and timing of the Last Glacial Maximum (LGM) in the Lake McKenzie record were in agreement with previously published nearby marine climate records. The amplitude of lower-than-present MAAT during the LGM potentially provides information on the latitude of separation of the Tasman Front from the East Australian current in the subtropical western Pacific. The Lake McKenzie record shows an earlier onset of near modern day warm temperatures in the early Holocene compared to marine records and the presence of a warmer than present day period during the mid-Holocene.

Benthic polychaetes in the largest intertidal mudflat of Hong Kong were analysed for potentially stressed environmental conditions from pollution. Over a two-year period, a total of 14 species were recorded with the species diversity (H′(log2)) ranged from 0.54 to 2.4. The community was dominated by two large polychaetes (Neanthes glandicincta and Potamilla acuminata) and a number of small pollution tolerant species (Tharyx, Capitella capitata and Prionospio cirrifera). It was also characterized by both temporal and spatial variations in terms of abundance and species composition with the lowest species number observed at onshore Station B in August and the highest at offshore Station D in February. Two distinct polychaete communities were formed along the intertidal towards subtidal mudflat, particularly the assemblage at onshore Station B showing a significant difference from those at the other three stations (P < 0.05, N = 32). Results of the abundance–biomass comparison (ABC) indicated a typical impacted community at the whole study area, especially at Station B which was close to the Shenzhen River mouth and mangrove forest. The total organic carbon had a significant positive effect on the abundance of Capitella capitata (P = 0.037, N = 8) while sedimentary compositions were statistically related to the abundance of Potamilla acuminata, Tharyx and total abundance of polychaetes (P < 0.05, N = 8). In conclusion, both the polluted Shenzhen River and nearby mangrove may be responsible for the decline in species richness and diversity as well as changes in community structure. Polychaetes can be used as the appropriate indicators in habitat ecological condition assessment instead of the whole benthic community.