Changes in fish communities of the Phongolo floodplain, Zululand (South Africa) before, during and after a severe drought

Merron, Glenn S.; Bruton, Michael N.; Lalouviere, Philippe La Hausse De

doi:10.1002/rrr.3450080404

Cited by 24 publications

(18 citation statements)

References 5 publications

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“…However, when the environment becomes less predictable, opportunistic strategists and species with specific environmental adaptations such as hypoxia tolerance might be at an advantage, as shown for Area 4. This is in accordance with reports from African and Australian dryland rivers, which have less predictable flood pulses and where more opportunistic or physiologically tolerant species dominate (Merron, Bruton & De Lalouviere, 1993; Balcombe et al. , 2006, 2007).…”

Section: Discussionsupporting

confidence: 92%

Fish recruitment in a large, temperate floodplain: the importance of annual flooding, temperature and habitat complexity

et al. 2011

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1. Large river floodplains are considered key nursery habitats for many species of riverine fish. The lower Volga River floodplains (Russian Federation) are still relatively undisturbed, serving as a suitable model for studying the influence of flooding and temperature on fish recruitment in floodplain rivers. 2. We examined the interannual variability in recruitment success of young-of-the-year (YOY) fish in the lower Volga floodplain in relation to flood pulse characteristics and rising water temperatures in the spring. We sampled four areas with different flooding regimes, in three consecutive years (2006)(2007)(2008). 3. Extensive areas with a long duration of flooding accommodated high densities of young fish. This suggests that extended inundation improves the recruitment success of river fish. In areas with extensive flooding, the biomass of YOY of most fish species was about three times higher in 2006 and 2007 than in 2008. We hypothesise that low spring temperatures in 2008 may have caused this reduced recruitment and that a flood synchronised with rising temperature enhances recruitment success. 4. Extensive flooding was particularly favourable for species characterised by large body size, delayed maturation, high fecundity and low parental investment, such as pike Esox lucius, roach Rutilus rutilus and ide Leuciscus idus. Gibel carp Carassius gibelio, a species tolerant of high temperature and hypoxia, did particularly well in small waterbodies in the driest parts of the floodplain. 5. Structural characteristics of floodplain waterbodies explained much of YOY fish density. These species-environment associations varied from year to year, but some species such as common bream Abramis brama, roach and gibel carp showed consistent relationships with structural habitat characteristics in all years, despite large interannual fluctuations in flood pulse and spring temperature.

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Section: Discussionsupporting

confidence: 92%

Fish recruitment in a large, temperate floodplain: the importance of annual flooding, temperature and habitat complexity

et al. 2011

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“…In both the Darling and Murray regions, rivers are regulated predominantly to provide a secure supply of water for irrigation, with flood mitigation, town water supply and hydroelectric power generation accounting for relatively small proportions of the total flow. Flows in these rivers retain a strong seasonal pattern that is out of phase with the natural flow cycle, with a reduced mean annual flow volume and increased stability (Merron et al, 1993;Walker and Thoms, 1993;Gehrke et al, 1995;Imbert and Stanford, 1996). In contrast, regulated rivers in the North Coast and South Coast regions are mostly regulated to provide town water supplies.…”

Section: Discussionmentioning

confidence: 95%

“…For example, rivers that are regulated principally to provide water for irrigation during seasons of low rainfall, such as the Lachlan River, maintain a highly seasonal flow that is out of phase with the natural seasonal flow cycle (Merron et al, 1993;Walker and Thoms, 1993;Gehrke et al, 1995) (Figure 1). In these situations, the natural river channel is the major conduit of water for downstream use.…”

Section: Introductionmentioning

confidence: 99%

“…Regulation of stream flow by dams which impound water that would otherwise provide flow downstream is a major cause of degradation in aquatic riverine ecosystems around the world (Bain et al, 1988;Merron et al, 1993;Garcia de Jalon et al, 1994;Gehrke et al, 1995Gehrke et al, , 1999aHumphries et al, 1996;Zhong and Power, 1996). Ecological effects of flow regulation in Australia include changes in biofilm composition (Sheldon and Walker, 1997), populations of freshwater crayfish (Geddes, 1990), mussels and snails (Walker, 1992;Walker et al, 1992), fish (Cadwallader, 1978;Harris, 1988;Cadwallader and Lawrence, 1990), and declining species diversity in fish communities (Gehrke et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Regional‐scale effects of flow regulation on lowland riverine fish communities in New South Wales, Australia

Gehrke¹,

Harris²

2001

Regul. Rivers: Res. Mgmt.

102

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Lowland reaches of 40 rivers in New South Wales, Australia, were designated as 'regulated' or 'unregulated', depending upon the degree to which flows were modified by the operation of a dam upstream. Five replicate rivers of each type were selected from the North Coast, South Coast, Darling and Murray regions in the State. Fish communities in each river were sampled in summer and winter in two consecutive years. Regulated and unregulated rivers contained significantly different fish communities, although communities in each region retained characteristic features. The proportion of native species in the total catch was greater in unregulated rivers in all regions, ranging from 27% in the Murray region to 100% in South Coast rivers. In regulated rivers, native species made up 20% of the catch in the Murray region compared with a maximum of 99% in the North Coast. Carp, Cyprinus carpio, were the main alien species contributing to changes in the proportional abundance of native fish. Native species most affected by river regulation were western carp gudgeons, Hypseleotris spp., bony herring, Nematalosa erebi, and striped gudgeons, Gobiomorphus australis. Fifteen native species showed some effect of river regulation on their population structures. Individual species showed positive, negative or mixed positive and negative, effects of regulation, at population, species or community levels. Three abundant alien species and seven native species showed only positive or mixed responses, whereas 13 native species exhibited only negative effects. Flow regulation has reduced the resilience of New South Wales rivers and native fish communities to invasion by alien species. New research has commenced to investigate whether recently introduced environmental flow rules are effective in reducing the effects of river flow alteration on fish communities in New South Wales rivers.

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“…Such conditions go beyond the tolerance limits of other species such as bream (Backiel & Zawiswa 1968) and roach. In natural floodplain lakes, differential mortality occurs of fish species with different life histories (Lowe-McConnell 1975;Welcomme 1979;Merron et al 1993;Winemiller & Jepsen 1998;Winemiller et al 2000), and may even determine species composition to a greater extent than immigration during connection (Halyk & Balon 1983;Tejerina-Garro et al 1998). Along the regulated and embanked lower Rhine almost all the floodplain lakes become connected to the main channel almost every year.…”

Section: Discussionmentioning

confidence: 99%

The status of limnophilic fish and the need for conservation in floodplains along the lower Rhine, a large regulated river

Grift¹,

Buijse²,

Geest³

2006

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Recovery of the fish community of the river Rhine focussed mainly on the return of migratory species, in particular the Atlantic Salmon, Salmo salar, and to a lesser extent on rheophilic fish species. Several limnophilic species that characterize remote parts of the floodplains are, however, also endangered.The status of the fish communities in the floodplains is little known and has been neglected so far. To fill this gap, the present study investigated fish communities in floodplain lakes along the lower River Rhine. To assess how these lakes contribute to fish species richness in the river-floodplain system, the community structure is compared to that in the main channel and to connected backwaters, e.g. side channels, which had been investigated more intensively in recent years.Floodplain lakes with abundant vegetation may have low fish species richness, but they are the only sites with suitable habitats for the reproduction of limnophilic species such as tench Tinca tinca, rudd Scardinius erythrophthalmus and crucian carp Carassius carassius. Limnophilic species in most of these lakes are, however, outnumbered by eurytopic species such as bream Abramis brama, which indicates that the original lateral gradient is truncated with an almost complete loss of`black fish' habitats in the present active floodplains along the lower Rhine.Floodplain lakes with abundant vegetation should be carefully preserved because they represent original aquatic components that have declined markedly, and they need decades to develop. Preservation of these lakes would enhance the conservation of characteristic limnophilic species. Retention areas outside the present active floodplain ± retained as a component of flood risk management ± may provide the opportunity to rehabilitate or

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Changes in fish communities of the Phongolo floodplain, Zululand (South Africa) before, during and after a severe drought

Cited by 24 publications

References 5 publications

Fish recruitment in a large, temperate floodplain: the importance of annual flooding, temperature and habitat complexity

Fish recruitment in a large, temperate floodplain: the importance of annual flooding, temperature and habitat complexity

Regional‐scale effects of flow regulation on lowland riverine fish communities in New South Wales, Australia

The status of limnophilic fish and the need for conservation in floodplains along the lower Rhine, a large regulated river

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