Data from: Incomplete datasets obscure associations between traits affecting dispersal ability and geographic range size of reef fishes in the Tropical Eastern Pacific

Dispersal is thought to be an important process determining range size, especially for species in highly spatially structured habitats, such as tropical reef fishes. Despite intensive research efforts, there is conflicting evidence about the role of dispersal on determining range size. We hypothesize that traits related to dispersal drive range sizes, but that complete and comprehensive datasets are essential for detecting relationships between species’ dispersal ability and range size. We investigate the roles of six traits affecting several stages of dispersal (adult mobility, spawning mode, pelagic larval duration (PLD), body size, aggregation behaviour and circadian activity), in explaining range size variation of reef fishes in the Tropical Eastern Pacific (TEP). All traits, except for PLD (148 species), had data for all 497 species in the region. Using a series of models, we investigated which traits were associated with large range sizes, when analysing all TEP species or only species with PLD data. Furthermore, using null models, we analysed whether the PLD-subset is representative of the regional species pool. Several traits affecting dispersal ability were strongly associated with range size, although these relationships could not be detected when using the PLD-data subset. Pelagic spawners (allowing for passive egg dispersal) had on average 56% larger range sizes than non-pelagic spawners. Species with medium or high adult mobility had on average a 25% or 33% larger range, respectively, than species with low mobility. Null models showed that the PLD-subset was non-representative of the regional species pool, explaining why model outcomes using the PLD-subset differed from the ones based on the complete dataset. Our results show that in the TEP, traits affecting dispersal ability are important in explaining range size variation. Using a regionally complete dataset was crucial for detecting the theoretically expected, but so far empirically unresolved, relationship between dispersal and range size.,Alzateetal_2018_EE_data_finalData on geographic distribution of 497 reef fish species was obtained from the Shorefishes of the Tropical Eastern Pacific (SFTEP), Online Information System (Robertson & Allen, 2016) and the IOBIS data base (to complete the distributions of species that are not endemic to the TEP). We restricted our study to the distribution of tropical reef-associated bony fishes in the TEP region (sensu Robertson & Allen, 2016). We included only tropical species, whose main distribution occurs in the Pacific Ocean. Range size was calculated using the geographical coordinates of all records reported in the region. Range size was measured as the maximum linear distance (in kilometres) between any two points where a species has been recorded. In addition, we collated information on several species traits potentially affecting dispersal from the literature and online databases: body size, adult mobility, spawning mode, PLD, circadian activity and aggregation behaviour. All of these factors have been suggested as possible drivers of range size in reef fishes.,