2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/21/2019 | 9:30 AM - 9:45 AM | DIS-ENTANGLING ECOLOGICAL NICHE PATTERNS OF NATIVE AND NON-NATIVE FISHES WITHIN AN INVADED AFRICAN RIVER SYSTEM | 151 DEF
DIS-ENTANGLING ECOLOGICAL NICHE PATTERNS OF NATIVE AND NON-NATIVE FISHES WITHIN AN INVADED AFRICAN RIVER SYSTEM
Ecological niche theory predicts that spatial organisation for species in natural communities is driven by niche differentiation arising from both physical and biotic interactions. By comparison, successful invaders are assumed to override this theory because they are considered to be driven by niche opportunities that facilitate the invaders to exploit a wide resource range. We tested these hypotheses by comparing environmental and isotopic niches of native and non-native fishes within an invaded African river system. For the native fishes, we found contrasting environmental niches that varied from being small to being large, and that overlapped for most species. Stable isotope analyses revealed isotopic niche segregation for species with overlapping environmental niches. Most non-native fishes were found to have broad environmental niches, with high tolerance to environmental conditions, which partly supported the niche opportunity hypothesis. These fishes, nevertheless, exhibited isotopic niche segregation, which suggested that resource utilization was either non-random or was explained by trophic niche conservatism. Based on these distribution and isotopic patterns, we inferred the likelihood of negative interactions between native and non-native fishes. Such effects are likely exacerbated by altered flow regime that may affect the native ichthyofauna.
- Invasives
- Isotope
- Spatial
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Presenters/Authors
Wilbert Kadye
(), Rhodes University, South Africa, w.kadye@ru.ac.za;
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Tony Booth
(), Rhodes University, South Africa, t.booth@ru.ac.za;
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