Marine and Freshwater Research最新文献

Conservation of coral-reef fishes requires an understanding of their spatial and temporal responses to climate change and anthropogenic disturbance, which also requires an understanding of patterns in their taxonomic diversity.

To describe the species composition, taxonomic diversity and G-F diversity-measurement index of Qilianyu Island and Meiji Reef, South China Sea, coral-reef fish assemblages.

Coral reef-dwelling fish were sampled in 2018 and 2019 at Meiji Reef and Qilianyu Island by using various fishing gears, identified to the lowest taxonomic category, and their taxonomic relatedness was compared at levels of class, order, family, genus and species.

The reef-dwelling fish fauna of this region comprises 123 species in 5 orders (dominated by Perciformes, at 78%), 22 families and 46 genera. The average taxonomic distinctness (Δ⁺) of Qilianyu Island fish assemblages is 55.52, and variation in taxonomic distinctness (Λ⁺) is 138.18; for Meiji Reef, values for Δ⁺ and Λ⁺ are 53.02 and 135.33 respectively.

High species diversity and low taxonomic diversity are important features of coral-reef fish assemblages in the South China Sea.

The high species diversity of reef fish in the South China Sea, along with a well-distributed assemblage of families and genera, is crucial for preserving the region’s fish biodiversity. Consequently, timely prioritisation of reef fish conservation is essential.

Water pumps fitted with filtering screens are effective for delivering water to floodplain environments and excluding large-bodied exotic fish; yet, the benefits to wetland fish and anurans are unknown.

To quantify fish and tadpole responses to refilling wetlands with water pumps fitted with large-mesh screens following drawdown v. overland reconnections in the mid-Murrumbidgee region of New South Wales.

Frog and fish communities were compared between wetlands under managed inundation and overland reconnections by using PERMANOVA, and non-metric multidimensional scaling was used to evaluate community divergence between watering strategies. Classification and regression trees were used to identify thresholds in explanatory variables and predicted threshold responses in fish and tadpole abundance.

Fish and tadpole communities differed in relation to watering strategies. Managed inundation resulted in a higher abundance of tadpole species and one native fish, whereas overland reconnections resulted in a high abundance of exotic fish species and fewer tadpoles. Water depth was a driver of tadpole abundance in two species, including the threatened southern bell frog (Litoria raniformis).

Using filtered pumps with large-mesh screens to deliver water to wetlands of high conservation value may be an effective strategy for reducing large-bodied exotic fish and enhancing frog and fish populations in regulated floodplain systems.

Environmental water is often used to manage floodplain wetlands that support many taxa, both terrestrial and aquatic. It is important to optimise the managed hydroperiod to maximise the provision of aquatically derived resources from wetlands.

To test the hypothesis that increasing hydroperiod affects food-web structure and energy production in floodplain wetlands.

Fatty acids and stable isotopes of δ¹³C and δ¹⁵N were used to define food-web structure, and estimate total energy production throughout a managed inundation event in a wetland in the northern Murray–Darling Basin.

Food-web complexity increased with an increasing hydroperiod in line with predictable patterns of community assemblage development, before reducing sharply immediately prior to drying. Energy availability increased with an increasing hydroperiod and there was a strong correlation (ρ = 0.669, P = 0.0001) between energy availability and fatty acid concentration, which was in turn related to patterns of taxon occurrence.

Hydroperiod exerts a strong influence on aquatic invertebrate community trophic dynamics and energy provision. Planned flows should support maturation and stabilisation of the invertebrate community to optimise energy provision to consumers.