Monitoring the silver carp invasion in Africa: a case study using environmental DNA (eDNA) in dangerous watersheds

By

Crookes, Steve
Heer, Tej
Castaneda, Rowshyra
Mandrak, Nicholas
Heath, Daniel
Weyl, Olaf
MacIsaac, Hugh
Foxcroft, Llewellyn

Type

Article

Date of Publication

2020

Original Publication

NeoBiota : advancing research on alien species and biological invasions

Volume

56

Pages

31--47

Subjects

Asian carp , biomonitoring , hazardous sampling , invasive species , species detection

Contributed by

Pensoft Publishers

Language

English

Published by

Sophia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/neobiota.56.47475

 

Abstract

Biodiverse habitats are increasingly subject to an intensification of anthropogenic stressors that may severely diminish species richness. Invasive species pose a dominant threat to biodiversity and biosecurity, particularly in biodiversity hotspots like Kruger National Park, South Africa. The invasive silver carp, Hypophthalmichthys molitrix, was introduced into the Olifants River and may experience range spread owing to favorable environmental conditions. Intensive monitoring protocols are necessary to effectively manage invasions of species like silver carp. Unfortunately, tropical and sub-tropical aquatic systems are difficult to monitor using conventional methods (e.g., netting, electrofishing and snorkeling) owing to a range of factors including the presence of dangerous megafauna. Conservation of such systems may be advanced by the adoption of novel methods, including environmental DNA (eDNA) detection. Here, we explore the utility of environmental DNA (eDNA) to conduct safe, reliable and repeatable surveys in dangerous watersheds using silver carp as a case study. We conducted eDNA surveys at 12 sites in two neighbouring watersheds, and determined that the species has expanded its range within the Olifants River and to the south in the Sabie River. Expansion in the former is consistent with the presence of suitable spawning conditions. We discuss the implications of this survey for biodiversity monitoring in similar aquatic systems in the tropics and advocate an integrative approach to biomonitoring in these ecosystems.