Long-term changes in freshwater molluscan communities in the middle stretch of the Danube River (Slovakia) over a 23-year period

Beracko, Pavel; Matečný, Igor; Košel, Vladimír

doi:10.1127/fal/2016/0824

Cited by 5 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4). Though this is not the only case (Curry and Baird, 2015;Beracko et al, 2016), the source of the uncertainty in community composition needs to be evaluated. We can most likely exclude any spatially structured unmeasured environmental factor.…”

Section: Combined Influence Of Environment Dispersal and The Indirementioning

confidence: 99%

“…In particular, diversity in vegetation and substrates has been found to account for differences in riverine mollusk communities (Maqboul et al, 2014;Reckendorfer et al, 2006). In addition, climate conditions and anthropogenic influences play also an important role in shaping modern distribution patterns of freshwater mollusks (Barkia et al, 2014;Van Bocxlaer et al, 2015;Beracko et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mollusk communities of the central Congo River shaped by combined effects of barriers, environmental gradients, and species dispersal

et al. 2017

View full text Add to dashboard Cite

Rapids, falls, and cascades might act as barriers for freshwater species, determining the species community up-and downstream of barriers. However, they affect community composition not only by acting as barriers but also by their influence on environmental gradients. Moreover, the directional dispersal of species along the watercourse might determine community composition. A suitable system to study these differential effects is the Congo River, the world's second largest river by discharge. The small 'Upper Congo Rapids' ecoregion features several rapids known as barrier for fish. The Wagenia Cataract at the town of Kisangani constitutes the strongest drop of the Congo River and several studies have emphasized its role as barrier for fish distribution. Alternative explanations for this pattern, however, are rarely evaluated. Though mollusks represent a vital component of the macrozoobenthos, with distribution patterns and underlying drivers often distinct from that of fishes, virtually no field surveys of the Congo River have been reported for decades. We collected and determined mollusks of 51 stations, recorded environmental conditions, and generated proxies for directional species dispersal and an indirect barrier effect. Those variables were subjected to distance-based redundancy analyses and variation partitioning in order to test whether the mollusk community compositions are better explained by an individual or combined influence of the direct and indirect effect of the cataract barrier, environmental conditions, and downstreamdirected dispersal. Our survey showed an exclusive upstream/downstream distribution for just four out of the 19 species, suggesting a limited barrier effect. We revealed no direct influence of the barrier itself on community composition but of substrate type. However, we found an indirect effect of the barrier through replacing spatially structured communities upstream of the cataract with more uniform ones downstream. Downstream-directed dispersal explained the highest fraction of variation in mollusk communities. Thus, environmental factors, the indirect cataract effect, and downstream-directed spatial proxies model mollusk community composition in concert. These results support previous studies showing a multi-factorial imprint on communities. However, a large fraction of variation community composition remained unexplained, potentially due to flood plain dynamics that (re-)shape mollusk communities constantly and a high temporal turnover, evidenced by the comparison with historical surveys. This is likely caused by the growth of Kisangani and resulting human activities. A monitoring system could allow better assessments of these impacts on communities and the conservation status of endemic species in the Wagenia Cataract.

show abstract

Section: Combined Influence Of Environment Dispersal and The Indirementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mollusk communities of the central Congo River shaped by combined effects of barriers, environmental gradients, and species dispersal

et al. 2017

View full text Add to dashboard Cite

show abstract

Changes in species composition of water insects during 25-year monitoring of the Danube floodplains affected by the Gabčíkovo waterworks

Krno

Beracko

Navara

et al. 2018

Environ Monit Assess

View full text Add to dashboard Cite

This study was based on the complex environmental monitoring of the Danube River in Slovakia. Out of 23 monitored sites, three were chosen for the aim of this study. The three sites were sampled regularly three times per year during a 25-year period, which started in 1990, 2 years before the Gabčíkovo waterworks became operational. Each site represented one of the main potamal types, which we recognised according to the habitat characteristics as eupotamal, parapotamal and plesiopotamal. In order to assess changes which occurred during the 25 years, we studied taxocoenoses of Ephemeroptera, Plecoptera and Trichoptera, which sensitively reflect anthropogenic impacts. The changes caused by the Gabčíkovo waterworks manifested in a decrease of the species diversity in eupotamal because of the disappearance of rheophilous taxa. In the parapotamal and plesiopotamal sites, the initial decrease was followed by a partial recovery of biodiversity due to the artificial floodings. After they were stopped, the decrease occurred again and until 2015, the insect taxa became rare. Conversely, in the eupotamal site, there was an increasing trend in biodiversity since 2011 until 2015. Overall increase in the floodplain index values indicated a loss of connectivity between the floodplain habitats and their fauna with the main channel during the last 25 years. In this paper, we also extended the floodplain index with data on habitat values and indication weight for several stonefly species.

show abstract

RETRACTED: Ecological risk assessment of coastal ecosystems: The case of mangrove forests in Hormozgan Province, Iran

et al. 2018

View full text Add to dashboard Cite

Long-term changes in freshwater molluscan communities in the middle stretch of the Danube River (Slovakia) over a 23-year period

Cited by 5 publications

References 0 publications

Mollusk communities of the central Congo River shaped by combined effects of barriers, environmental gradients, and species dispersal

Mollusk communities of the central Congo River shaped by combined effects of barriers, environmental gradients, and species dispersal

Changes in species composition of water insects during 25-year monitoring of the Danube floodplains affected by the Gabčíkovo waterworks

RETRACTED: Ecological risk assessment of coastal ecosystems: The case of mangrove forests in Hormozgan Province, Iran

Contact Info

Product

Resources

About