Patterns and drivers of fish extirpations in rivers of the American Southwest and Southeast

John S. Kominoski, Albert Ruhí, Megan M. Hagler, Kelly Petersen, John Sabo, Tushar Sinha, Arumugam Sankarasubramanian, Julian D. Olden

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Effective conservation of freshwater biodiversity requires spatially explicit investigations of how dams and hydroclimatic alterations among climate regions may interact to drive species to extinction. We investigated how dams and hydroclimatic alterations interact with species ecological and life history traits to influence past extirpation probabilities of native freshwater fishes in the Upper and Lower Colorado River (CR), Alabama-Coosa-Tallapoosa (ACT), and Apalachicola-Chattahoochee-Flint (ACF) basins. Using long-term discharge data for continuously gaged streams and rivers, we quantified streamflow anomalies (i.e., departure “expected” streamflow) at the sub-basin scale over the past half-century. Next, we related extirpation probabilities of native fishes in both regions to streamflow anomalies, river basin characteristics, species traits, and non-native species richness using binomial logistic regression. Sub-basin extirpations in the Southwest (n = 95 Upper CR, n = 130 Lower CR) were highest in lowland mainstem rivers impacted by large dams and in desert springs. Dampened flow seasonality, increased longevity (i.e., delayed reproduction), and decreased fish egg sizes (i.e., lower parental care) were related to elevated fish extirpation probability in the Southwest. Sub-basin extirpations in the Southeast (ACT n = 46, ACF n = 22) were most prevalent in upland rivers, with flow dependency, greater age and length at maturity, isolation by dams, and greater distance upstream. Our results confirm that dams are an overriding driver of native fish species losses, irrespective of basin-wide differences in native or non-native species richness. Dams and hydrologic alterations interact with species traits to influence community disassembly, and very high extirpation risks in the Southeast are due to interactions between high dam density and species restricted ranges. Given global surges in dam building and retrofitting, increased extirpation risks should be expected unless management strategies that balance flow regulation with ecological outcomes are widely implemented.

Original languageEnglish (US)
Pages (from-to)1175-1185
Number of pages11
JournalGlobal change biology
Volume24
Issue number3
DOIs
StatePublished - Mar 2018

Keywords

  • biodiversity loss
  • dams
  • flow regime
  • global change
  • imperiled species

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

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    Kominoski, J. S., Ruhí, A., Hagler, M. M., Petersen, K., Sabo, J., Sinha, T., Sankarasubramanian, A., & Olden, J. D. (2018). Patterns and drivers of fish extirpations in rivers of the American Southwest and Southeast. Global change biology, 24(3), 1175-1185. https://doi.org/10.1111/gcb.13940