Connectivity of fish communities in a tropical floodplain river system and predicted impacts of potential new dams

O’Mara, Kaitlyn; Venarsky, Michael P.; Stewart‐Koster, Ben; McGregor, Glenn B.; Schulz, Cameron; Kainz, Martin J.; Marshall, Jonathan; Bunn, Stuart

doi:10.1016/j.scitotenv.2021.147785

Cited by 22 publications

(6 citation statements)

References 66 publications

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“…Because both fish and macroinvertebrates are affected by changes in water quality and forest area (especially in the riparian zone), this difference may be driven by the hydromorphological alterations of rivers. Fish move across larger spatial scales and across habitats within rivers than invertebrates to access food resources and complete their life cycles(O'Mara et al, 2021). Therefore, they are severely affected by losses in longitudinal connectivity caused by the widespread fragmentation of rivers and streams by dams, reservoirs, and poorly constructed road-stream crossings for at least three reasons: (1) Fish cannot pass physical barriers (as can the flying adult stages of many aquatic insects).…”

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confidence: 99%

Fish and macroinvertebrate assemblages reveal extensive degradation of the world's rivers

Feio

Hughes

Serra

et al. 2022

Global Change Biology

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Rivers suffer from multiple stressors acting simultaneously on their biota, but the consequences are poorly quantified at the global scale. We evaluated the biological condition of rivers globally, including the largest proportion of countries from the Global South published to date. We gathered macroinvertebrate‐ and fish‐based assessments from 72,275 and 37,676 sites, respectively, from 64 study regions across six continents and 45 nations. Because assessments were based on differing methods, different systems were consolidated into a 3‐class system: Good, Impaired, or Severely Impaired, following common guidelines. The proportion of sites in each class by study area was calculated and each region was assigned a Köppen‐Geiger climate type, Human Footprint score (addressing landscape alterations), Human Development Index (HDI) score (addressing social welfare), % rivers with good ambient water quality, % protected freshwater key biodiversity areas; and % of forest area net change rate. We found that 50% of macroinvertebrate sites and 42% of fish sites were in Good condition, whereas 21% and 29% were Severely Impaired, respectively. The poorest biological conditions occurred in Arid and Equatorial climates and the best conditions occurred in Snow climates. Severely Impaired conditions were associated (Pearson correlation coefficient) with higher HDI scores, poorer physico‐chemical water quality, and lower proportions of protected freshwater areas. Good biological conditions were associated with good water quality and increased forested areas. It is essential to implement statutory bioassessment programs in Asian, African, and South American countries, and continue them in Oceania, Europe, and North America. There is a need to invest in assessments based on fish, as there is less information globally and fish were strong indicators of degradation. Our study highlights a need to increase the extent and number of protected river catchments, preserve and restore natural forested areas in the catchments, treat wastewater discharges, and improve river connectivity.

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confidence: 99%

Fish and macroinvertebrate assemblages reveal extensive degradation of the world's rivers

Feio

Hughes

Serra

et al. 2022

Global Change Biology

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“…), bats, and piscivorous birds (kingfishers, osprey, etc. ), that can move across the floodplain, selecting from a diversity of local aquatic communities and food webs that intact floodplain mosaics may support (Bellmore et al, 2013(Bellmore et al, , 2015O'Mara et al, 2021). This biological portfolio may also help stabilize the dynamics of the aquatic ecosystem (Schindler et al, 2015) and aid in maintaining biological production and diversity as extreme events (e.g., floods, fires, and droughts) become more frequent and severe in a changing world.…”

Section: Discussionmentioning

confidence: 99%

Effects of process‐based floodplain restoration on aquatic macroinvertebrate production and community structure

Jennings

Bellmore

Armstrong

et al. 2023

River Research & Apps

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Recent stream restoration approaches, such as Stage 0 restoration, aim to restore natural processes to regain lost ecosystem functions, but project implementation can also represent a reach‐scale disturbance. Assumed outcomes of these restoration actions, like greater biological productivity, are rarely evaluated. In this study, we examined the short‐term effects of Stage 0 floodplain restoration on the secondary production of aquatic macroinvertebrate communities in the South Fork McKenzie River, Oregon, 1–2 years following project implementation. We seasonally sampled macroinvertebrates from benthic and submerged wood surfaces in the restored reach, and two unrestored reference reaches located upstream, to estimate annual secondary production. Macroinvertebrate production estimates were 3× lower on a per‐meter‐squared basis in the restored reach than in the upstream unrestored reference reaches (9764 vs. 29,636 mg DM/m2/yr). However, because there was 4.5‐times greater wetted area available in the restored reach, overall macroinvertebrate production per unit of valley length was 3.4× higher in the restored reach than in unrestored reference reaches (2744 vs. 802 kg DM/km). Additionally, the mosaic of aquatic habitats created via restoration (main‐channel, side‐channel, and wetted forest habitats) supported a diversity of macroinvertebrate assemblages both within and among reaches. Our findings suggest Stage 0 project implementation, which can include dewatering and filling incised channels, may reduce aquatic macroinvertebrate production on a per‐unit‐area basis for at least 1 or 2 years following restoration. However, this short‐term disturbance effect may be offset by channel aggradation and widening, which can provide a more wetted area for macroinvertebrate production and may support greater macroinvertebrate community diversity. Future studies are needed to examine the longer term (2–10 years) aquatic macroinvertebrate response to Stage 0 restoration, and the impacts of shifting resource availability on stream fishes.

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“…Wetland macrophytes provide habitat structure for macroinvertebrates and a surface for epiphyton growth, and are therefore important for supporting fish biomass through the dry season until the wetlands become reconnected to the river network (Thomaz et al., 2008). The Mitchell River system has relatively unregulated flow and fish are able to use seasonal connectivity to move freely across habitats (Jardine et al., 2012; O’Mara et al., 2021). The pressure to expand agriculture and regulate river flow not only threatens the movement potential for fish, but also threatens food quality through changes in microhabitat leading to shifts in community structure and composition of macroinvertebrates (Bowen et al., 2003; Leigh et al., 2013).…”

Section: Discussionmentioning

confidence: 99%

Trophic transfer of lipids and fatty acids across habitats in tropical river food webs

et al. 2022

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1. Polyunsaturated fatty acids (PUFA) are essential components of cell membranes and reproductive and sensory organs in vertebrates and are largely acquired through their diets. Accordingly, identification of the dietary sources of PUFA is an important consideration in food web studies.2. We collected fish, macroinvertebrates (aquatic and terrestrial), and plants (aquatic and terrestrial) from floodplain and river channel habitats in a tropical river catchment in northern Australia, to identify food sources and habitats that provided lipid and PUFA rich food that sustain fish populations.3. The composition of most FA in fish was similar to that reported from other freshwater tropical environments, with the exception of their higher arachidonic acid content. Fish were found to derive their fatty acids primarily from aquatic sources of food and had similar FA composition to aquatic macroinvertebrates.Aquatic macroinvertebrates fed on aquatic plants (algae) and had higher total lipids and FA contents than plants and fish, providing a more concentrated source of PUFA for fish. Fish obtained most of their FA from their diet except for docosahexaenoic acid (DHA), which they must synthesize due to low DHA in algae and macroinvertebrates.4. There was no overall difference in basal dietary FA composition between floodplain and river channel habitats. However, macroinvertebrate taxa varied in their lipid and PUFA content.5. Food quality for fish may therefore vary between habitats as a consequence of differences in macroinvertebrate community composition. Given the high algal production on floodplains compared to the river channels, these habitats are likely to represent the major source of high quality food for fish and other aquatic consumers, and conserving habitats that are rich in lipids and PUFA is important for maintaining healthy fish communities.

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Connectivity of fish communities in a tropical floodplain river system and predicted impacts of potential new dams

Cited by 22 publications

References 66 publications

Fish and macroinvertebrate assemblages reveal extensive degradation of the world's rivers

Fish and macroinvertebrate assemblages reveal extensive degradation of the world's rivers

Effects of process‐based floodplain restoration on aquatic macroinvertebrate production and community structure

Trophic transfer of lipids and fatty acids across habitats in tropical river food webs

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