Amazon floodplain hydrology and implications for aquatic conservation

Mélack, John M.; Coe, Michael T.

doi:10.1002/aqc.3558

Cited by 31 publications

(19 citation statements)

References 104 publications

(147 reference statements)

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“…A lack of oxygen may limit the presence and establishment of diving species in transformed reservoir environments. Reservoir installation requires the filling and permanent flooding of great surfaces, spanning part of the land ecosystems and destroying the Aquatic terrestrial transition zone (Bodie, 2001; Fearnside, 2019; Melack and Coe, 2020). In consequence the lotic system is transformed into a lentic system (Forsberg et al, 2017; Reid et al, 2019) and the natural flood pulse becomes artificially regulated (Timpe and Kaplan, 2017).…”

Section: Discussionmentioning

confidence: 99%

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Bárcenas-García

Michalski

Morgan

et al. 2021

Preprint

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Dams create many impacts on freshwater ecosystems and biodiversity. Freshwater turtles are at direct and indirect risk due to changes caused by damming including the loss of terrestrial and aquatic nesting and feeding habitats, changes to resource availability and reduced dispersal. We reviewed the global scientific literature that evaluated the impact of dams on freshwater turtles, and carried out additional searches of literature published in seventeen languages for studies evaluating actions to mitigate the impact of dams. The search produced 43 published articles documenting dam impacts on 29 freshwater turtle species from seven families (Chelidae, Chelydridae, Emydidae, Geoemydidae, Kinosternidae, Podocnemididae and Trionychidae) in 13 countries. More than a third of studies (41.9%, n = 18) focused on nine North American species of the Emydidae. Few studies were found from Europe and Asia and none from Africa. The number of studies, life-history stage studied and threat status differed significantly between temperate and tropical latitudes. Most studies were from temperate latitudes, where studies focused more on adults and less threatened species compared with tropical latitudes. Studies evaluated dam impacts as barriers and changes to water flow and quality, but no studies were found that assessed turtles and changes to land cover or mercury caused by dams. More than half of the studies (59%, n = 24) suggested actions to help mitigate dam impacts. Yet, only four studies on three temperate and one tropical species documented the effect of interventions (dam removal, flow management, artificial pond maintenance and community-based action). These findings demonstrate a lack of documented evidence evaluating dam impacts on freshwater turtles particularly in tropical regions. This lack of evidence reinforces the importance of strengthening and maintaining robust long-term studies of freshwater turtles needed to develop effective conservation actions for this group of vertebrates.

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Section: Discussionmentioning

confidence: 99%

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Bárcenas-García

Michalski

Morgan

et al. 2021

Preprint

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“…Consequently, the conservation of flood forests is very important for the survival of the Amazonian fish species and assemblages that use these areas (Castello et al, 2019), susceptible to anthropogenic impacts (plastic pollutions, etc.) and extreme climatic variations (Melack & Coe, 2021).…”

Section: Discussionmentioning

confidence: 99%

Population dynamics of Mylossoma albiscopum (Characiformes: Serrasalmidae) in the Ucayali River

2021

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Mylossoma albiscopum show high levels of fishing landing in Pucallpa city (Ucayali Region, Peru). Nevertheless, information available about the population and reproductive parameters and exploitation of this species, is limited. Reason that motivated the development of this research, whose basis was the analysis of information on length frequencies and biological records in the Ucayali River at 2011–2019, moreover, to attain reproductive parameters, 11005 individuals were analyzed and sampled from the main fish landing sites of Pucallpa city. Females reach the mean length at first gonadal maturity at 14 cm (1.13 years) and males at 13.6 cm (1.29 years) of total length, respectively. The equations for theoretical growth according to the von Bertalanffy are defined by Lt = 33.81*(1 − e−0.38(t−0.42)) for unsexed, Lt = 32.26*(1 − e−0.38(t−0.43)) for females and Lt = 29.93*(1 − e−0.38(t−0.44)) for males; these results allow inferring that this species has fast growing and maximum age at 7.46. Exploitation rate was estimated to be 0.61 years−1, expressing overfishing values, which would involve generating a Fishery Management Plan for its conservation and sustainability in the Ucayali Region.

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“…Distance to the hydropower dam was calculated along the river network using the riverdist package (Tyers, 2020) in R (R Core Team, 2020). Rainfall is an important determinant of annual and seasonal variation in Amazonian river flow rates (Melack & Coe, 2021;Siddiqui et al, 2021), as such elevated precipitation during the months preceding nesting could result in nesting areas remaining submerged (Eisemberg et al, 2016). The total and standard deviation of precipitation (PPT) during each of the three months (July, August and September) prior to the peak of the nesting season in the six monitored years was calculated (Supporting Information S1).…”

Section: Explanatory Variablesmentioning

confidence: 99%

“…The ecological structure and complexity of Amazonian freshwater ecosystems is a result of myriad factors operating across different temporal and spatial scales, including flood pulse (Junk & Wantzen, 2006;Melack & Coe, 2021) and the spatial-temporal heterogeneity of seasonal rainfall (Melack & Coe, 2021;Reis et al, 2019;Siddiqui et al, 2021). But, diverse and globally important Amazonian ecosystem functions and services are threatened due to expansion of hydropower developments.…”

Section: Introductionmentioning

confidence: 99%

“…Freshwater turtle nesting areas are important for multiple Amazonian species not only for the turtles themselves (Campos-Silva et al, 2018). The seasonal reduction in river flow exposes river banks and islands, creating seasonally ephemeral habitats that represent essential resources for both freshwater and terrestrial biodiversity across Amazonia (Castello, 2021;Junk & Wantzen, 2006;Melack & Coe, 2021). These seasonal habitats are used by diverse oviparous wildlife (Campos-Silva et al, 2018;Campos-Silva et al, 2021) and their predators (da Costa Reis et al, 2021), and can also facilitate movements e.g.…”

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confidence: 99%

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Amazonian run-of-river dam reservoir impacts underestimated: Evidence from a Before-After Control-Impact study of freshwater turtle nesting areas

Bárcenas-García

Michalski

Gibbs

et al. 2021

Preprint

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1. Although the construction of hydropower dams is widely assumed to generate myriad negative impacts on biodiversity there remains a lack of robust scientific evidence documenting the magnitude of these impacts particularly across highly biodiverse tropical waterways. Hydropower expansion is an increasing threat to the Endangered yellow-spotted river turtle (Podocnemis unifilis) across its tropical South American range. 2. Turtle nesting-areas were monitored as an indicator of dry-season river level changes following run-of-river dam reservoir filling. A Before-After-Control-Impact (BACI) study design was established with multi-year field campaigns monitoring turtle nesting-areas along 66 km of river upstream of the dam, separated into 33 km control and impact zones. 3. The cause and extent of changes in nesting-areas was established using Generalized Additive Models. Nesting-area density was examined in relation to four variables: Before-After, Control-Impact, distance to the dam and precipitation. The extent of changes was examined by comparing the proportion of nesting-areas remaining in subzones during the four years after reservoir filling. 4. Comparison of the proportion of nesting-areas remaining after dam construction showed that a permanent dry season river level rise extended more than 20 km beyond impact assessment limits. On average the density of nesting-areas declined 69% (from 0.48 to 0.15 per km) across 33 km of river directly impacted by the dam. This loss was reflected in a significant BACI interaction. The variation in nesting-areas was not explained by seasonal precipitation, whilst nesting-area density increased significantly further away from the dam. 5. Standardized monitoring of freshwater turtle nesting-areas provided an effective means to quantify impacts of hydropower developments across biodiverse yet rapidly changing waterways. The negative impacts should be preventable by mitigation actions including habitat restoration and dry season flow regulation. Such measures are also likely to benefit multiple species in highly diverse Amazonian rivers increasingly impacted by run-of-river dams.

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Amazon floodplain hydrology and implications for aquatic conservation

Cited by 31 publications

References 104 publications

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Impacts of dams on freshwater turtles: a global review to identify conservation solutions

Population dynamics of Mylossoma albiscopum (Characiformes: Serrasalmidae) in the Ucayali River

Amazonian run-of-river dam reservoir impacts underestimated: Evidence from a Before-After Control-Impact study of freshwater turtle nesting areas

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