Data from: mapping endemic freshwater fish richness to identify high priority areas for conservation: an ecoregion approach

Freshwater ecosystems are experiencing accelerating global biodiversity
loss. Thus, knowing where these unique ecosystems’ species richness
reaches a peak can facilitate their conservation planning. By hosting more
than 290 freshwater fishes, Iran is a major freshwater fish hotspot in the
Middle East. Considering the accelerating rate of biodiversity loss, there
is an urgent need to identify species rich areas and understanding of the
mechanisms driving biodiversity distribution. In this study, we gathered
distribution records of all endemic freshwater fishes of Iran (85 species)
to develop their richness map and determine the most critical drivers of
their richness patterns from an ecoregion approach. We performed a
generalized linear model (GLM) with quasi-Poisson distribution to identify
contemporary and historical determinants of endemic freshwater fish
richness. We also quantified endemic fish similarity among the 15
freshwater ecoregions of Iran. Results showed that endemic freshwater fish
richness is highest in the Zagros Mountains while moderate level of
richness was observed between Zagros and Alborz Mountains. High, moderate
and low richness of endemic freshwater fish match with Upper Tigris
& Euphrates, Namak, and Kavir & Lut Deserts ecoregions
respectively. Kura - South Caspian Drainages and Caspian Highlands were
the most similar ecoregions and Orumiyeh was the most unique ecoregion
according to endemic fish presence. Precipitation and precipitation change
velocity since the Last Glacial Maximum were the most important predictors
of endemic freshwater fish richness. Areas identified to have the highest
species richness have high priority for the conservation of freshwater
fish in Iran, therefore, should be considered in future protected areas
development.