Variation in functional composition of reef fishes along a tropical to temperate gradient

AimsTransformations of species and functional compositions on subtropical reefs are ongoing due to poleward range shifts of some tropical species, with largely unknown consequences to ecosystem functioning. Trait-based approaches are powerful tools to quantify such changes. Here, we evaluated changes in the trait composition of coral-associated fish communities along a tropical to a temperate environmental gradient of ca.1400 km in southern Japan with abundance-weighted trait expression to assess how trait complexity changes with increasing latitude.
LocationRyukyu Islands and southern Pacific coast of Japan
TaxonReef fish
MethodsWe tested for shifts in trait space and functional redundancy, based on five morphological, life history, and behavioural traits: maximum length, pelagic larval duration, trophic level, substrate preference, and reproductive mode. Our trait database was coded with two approaches, first, by attributing a single value to each trait per species, and second, by fuz..., Study sites & data collectionVisual census fish surveys were carried out at 31 sites along the Pacific coast of Japan, located between 24o and 35o northern latitude, with climates ranging from tropical to temperate. This thermal gradient creates several areas with different environmental properties which were clustered into regions: tropical, warm subtropical, cold subtropical and warm temperate. Surveys were carried out along belt-transects (25m x 5m) in coral habitat, at a standardised depth of 8-12m during the northern summers in 2015 for all sites except sites 20-31, which were surveyed in 2016. At our most northern site (Tateyama), surveys were conducted at 3m depth as the coral habitat did not extend to deeper depths. We recorded individual fish lengths estimated to the nearest cm of all target species along the transects, whilst swimming along 5 replicate transects per site. The abundance of each species was counted visually and standardised using log(1+x) to meet normality a..., All data files can be opened in Excel. , # Title of Dataset: Variation in functional composition of reef fishes along a tropical-to-temperate gradient

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This file contains the data used to evaluate changes in the trait composition of coral-associated fish communities along a tropical to a temperate environmental gradient of ca.1400 km in southern Japan with abundance-weighted trait expression to assess how trait complexity changes with increasing latitude. Our trait database was coded with two approaches, first, by attributing a single value to each trait per species, and second, by fuzzy coding that allows more than one value per trait and hence considers some intraspecific trait variation.

## Description of the Data and file structure

The csv file titled \"JAPAN_JBI_LatitudinalGradient_key\" contains the trait abreviations key and explains the codes used throughout the other files.

The csv file titled \"JAPAN_JBI_LatitudinalGradient_CategoricalApproach_TraitDatabase\" contains the categorial approach trait values for each...