Environmental niche patterns of native and non‐native fishes within an invaded African river system. Issue 5 (7th May 2019)

• Record Type: Journal Article
• Authors: Kadye, Wilbert T.; Booth, Anthony J.
• Other Names: Weyl Olaf L. F. guestEditor.; Chakona Albert guestEditor.
• Is Part Of: Journal of fish biology. Volume 96:Issue 5(2020)
• Page Start: 1269
• Page End: 1277
• Publication Date: 2019-05-07
• Subjects: distribution patterns -- environmental niche -- invasions -- native fishes -- niche segregation -- spatial organisation; Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.13988
• Languages: English
• ISSNs: 0022-1112

Abstract

Abstract: To test ecological niche theory, this study investigated the spatial patterns and the environmental niches of native and non‐native fishes within the invaded Great Fish River system, South Africa. For the native fishes, there were contrasting environmental niche breadths that varied from being small to being large and overlapped for most species, except minnows that were restricted to headwater tributaries. In addition, there was high niche overlap in habitat association among fishes with similar distribution. It was therefore inferred that habitat filtering‐driven spatial organisation was important in explaining native species distribution patterns. In comparison, most non‐native fishes were found to have broad environmental niches and these fishes showed high tolerance to environmental conditions, which generally supported the niche opportunity hypothesis. The proliferation of multiple non‐native fishes in the mainstem section suggest that they form a functional assemblage that is probably facilitated by the anthropogenic modification of flow regimes through inter‐basin water transfer. Based on the distribution patterns observed in the study, it was inferred that there was a likelihood of negative interactions between native and non‐native fishes. Such effects are likely to be exacerbated by altered flow regime that was likely to have negative implications for native ichthyofauna.