Mapping endemic freshwater fish richness to identify high priority areas for conservation: an ecoregion approach

Abstract

Freshwater ecosystems are among the most threatened ecosystems. Thus, knowing where these unique ecosystems’ species richness reaches a peak can facilitate their conservation planning. By hosting 289 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 driver of their richness pattern with 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 and 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. Precipitation and precipitation change velocity since the Last Glacial Maximum were the most important predictor of 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.

Mapping endemic freshwater fish richness to identify high‐priority areas for conservation: An ecoregion approach

“…This checklist contains all valid endemic freshwater fishes of Iran until December 2022 (Table 1). In this study, distribution records of the endemic freshwater fish are based on our team's long‐term fieldworks (Figure 2) and opportunistic observations of freshwater fishes in Iran (Kafash, 2023; Yousefi et al., 2024). Fish sampling activities spanned across all Iranian basins from 2005 to 2022 (Jouladeh‐Roudbar et al., 2015, 2017, 2020), employing a range of methods including the backpack electro‐fisher (Samus 1000), hand nets, gill nets, and casting nets.…”

“…Current climate data are accessible form WorldClim (https://www.worldclim.org/data/worldclim21.html) and past climate data from PaleoClim (https://doi.org/10.1038/sdata.2018.254), other data are available at Kafash (2023) https://doi.org/10.5281/zenodo.10298559, and Yousefi et al. (2024) https://doi.org/10.5281/zenodo.10298559.…”