Global patterns of freshwater species diversity, threat and endemism

Abstract

AimGlobal-scale studies are required to identify broad-scale patterns in the distributions of species, to evaluate the processes that determine diversity and to determine how similar or different these patterns and processes are among different groups of freshwater species. Broad-scale patterns of spatial variation in species distribution are central to many fundamental questions in macroecology and conservation biology. We aimed to evaluate how congruent three commonly used metrics of diversity were among taxa for six groups of freshwater species.LocationGlobal.MethodsWe compiled geographical range data on 7083 freshwater species of mammals, amphibians, reptiles, fishes, crabs and crayfish to evaluate how species richness, richness of threatened species and endemism are distributed across freshwater ecosystems. We evaluated how congruent these measures of diversity were among taxa at a global level for a grid cell size of just under 1°.ResultsWe showed that although the risk of extinction faced by freshwater decapods is quite similar to that of freshwater vertebrates, there is a distinct lack of spatial congruence in geographical range between different taxonomic groups at this spatial scale, and a lack of congruence among three commonly used metrics of biodiversity. The risk of extinction for freshwater species was consistently higher than for their terrestrial counterparts.Main conclusionsWe demonstrate that broad-scale patterns of species richness, threatened-species richness and endemism lack congruence among the six freshwater taxonomic groups examined. Invertebrate species are seldom taken into account in conservation planning. Our study suggests that both the metric of biodiversity and the identity of the taxa on which conservation decisions are based require careful consideration. As geographical range information becomes available for further sets of species, further testing will be warranted into the extent to which geographical variation in the richness of these six freshwater groups reflects broader patterns of biodiversity in fresh water.

Riverine Ecosystem Management

“…These gaps mostly arise because of barriers that prevent existing data from being discoverable, accessible, and digestible (Wetzel et al 2015). The importance of the availability of large-scale datasets for analyzing and understanding the broadscale patterns of spatial variation in richness and endemism is highlighted by Collen et al (2013). This again is central to understanding the origin of diversity and the potential impacts of environmental change on current biodiversity patterns and allows for prioritization of conservation areas (Collen et al 2013).…”

“…This trend provides the factual justification for classifying freshwater ecosystems as the most threatened ecosystems on earth (www.millenniumassessment.org). Within freshwater ecosystems, running water species belong to the most endangered group of species as about half of running water species (vertebrates and crayfish) are threatened or their status is unknown (Collen et al 2014).…”

Estado de conservación y distribución de la biodiversidad de agua dulce en los Andes tropicales

“…La biodiversidad de estos ecosistemas, además, juega un papel vital en la provisión de recursos para los humanos, incluyendo alimento, forraje, medicinas, además de otros servicios indirectos como el control de inundaciones, iltración de agua, reducción de contaminación, recreación, entre otros (Strayer y Dudgeon 2010, Russi et al 2013. Sin embargo, la biodiversidad de agua dulce está siendo afectada a nivel global por una serie de factores que pone en peligro su persistencia (hieme et al 2010, Vörösmarty et al 2010, Collen et al 2014. Esto se puede ver relejado en el reporte publicado recientemente del Índice del Planeta Viviente, donde se muestra que la abundancia de las poblaciones de especies de agua dulce bajo monitoreo disminuyó en promedio un 76% entre 1970 y 2010; casi el doble de la reducción de las poblaciones terrestres y marinas, que disminuyeron 39% (WWF 2014).…”

Human-mediated processes affecting distribution and genetic structure ofSqualidus multimaculatus, a freshwater cyprinid with small spatial range

“…Thus, many of endemic species are primary targets of national conservation priorities (Lamoreux et al 2006). The conservation of endemic species is particularly important in freshwater ecosystems, because endemism is exceptionally high (Revenga et al 2005), and the global extinction rate of freshwater species is much higher than their terrestrial counterparts (Strayer and Dudgeon 2010;Collen et al 2014). To develop systematic conservation strategies of endemic freshwater species, historical and contemporary factors that have shaped its current distribution and genetic structure must be determined.…”