Ecological attributes of a tropical river basin vulnerable to the impacts of clustered hydropower developments

2008 ◽  
Vol 59 (11) ◽  
pp. 971 ◽  
Author(s):  
Marcus Sheaves ◽  
Nguyen Huu Duc ◽  
Nguyen Xuan Khoa

The Vu Gia – Thu Bon River Basin in central Vietnam is subject to extensive hydropower development, with eight major and at least 34 minor hydropower installations planned for completion over the next 10 years. This intense clustering of hydropower developments has the potential to impact on aquatic fauna and ecosystems extensively. We sampled freshwater and estuarine fish across the river basin to evaluate the current status of the fish fauna, to determine the extent of zonal and habitat specialisation, to determine the prevalence of migration as a component of life-history strategies, to evaluate the likely magnitude of impacts, and to highlight areas where management intervention is needed and where more extensive study is most urgently required. Given the current high levels of exploitation, the fish fauna appeared surprisingly intact; however, a number of attributes of the fauna, such as the prevalence of migration as a life-history tactic, make this fauna particularly vulnerable to the impacts of hydropower development. Without extensive mitigation, the combinations of habitat alteration in dam and diversion areas and the imposition of a proliferation of barriers to migration will lead to severe population fragmentation, increasing the potential for local extinction, and severely compromise opportunities for recolonisation.

2018 ◽  
Vol 66 (2) ◽  
pp. 605
Author(s):  
Diego Azevedo Zoccal Garcia ◽  
Alexandro Derly Augusto Costa ◽  
Fernanda Simões de Almeida ◽  
Andréa Bialetzki ◽  
Mário Luís Orsi

Fish diversity loss is threatened by the construction of dams as they prevent the regular natural dispersal among populations. Thus, conservation of key riverine habitats for fish reproduction may be essential for the recruitment of new native species of fish. The present study aimed to identify key habitats for fish spawning and early development in the Paranapanema River basin, as well as to determine the taxonomic composition, reproductive and life-history strategy, and to report spatial distribution of eggs, larvae and juveniles. The importance of lagoons, tributaries, and sub-tributaries was evaluated in the Paranapanema River basin between October 2012 and March 2013. Eggs and larvae samples were collected at dawn and dusk with conical plankton nets (0.5 mm mesh size), whereas juveniles were captured during the day with seine and sieve (0.5 cm mesh size). A total of 547 eggs, 904 larvae and 1 228 juveniles were captured. We observed that 2 larvae and 288 juveniles of non-migratory species, parental care, and equilibrium life-history strategy, predominated in lagoons and tributaries. On the other hand, 13 larvae and 60 juveniles of short migratory distance, no parental care, and periodic life-history strategy predominated in sub-tributaries. The highest densities of eggs were recorded in tributaries and sub-tributaries (Tukey’s test, P = 0.001 and P = 0.03, respectively), and the highest densities of larvae were recorded for lagoons and tributaries (P = 0.005 and P = 0.0001, respectively). Captures of eggs and larvae were higher at night; while the highest catches per unit effort of juveniles were recorded for tributaries and sub-tributaries. Fish species that adopt different life-history strategies can use diverse types of habitats during the early stages. Lagoons, tributaries and sub-tributaries of the Paranapanema River play different roles in the reproductive success of fish fauna in a heavily modified basin. The preservation of spawning and nursery areas trapped between reservoirs is necessary for Neotropical fish species recruitment and survival. Rev. Biol. Trop. 66(2): 605-621. Epub 2018 June 01. 


2013 ◽  
Vol 25 (4) ◽  
pp. 398-405 ◽  
Author(s):  
Cristina da Silva Gonçalves ◽  
Ursulla Pereira Souza ◽  
Fabio Cop Ferreira ◽  
Alexandre Peressin ◽  
Francisco Manoel de Souza Braga

AIM: Life-history strategies in fish include essential parameters related to offspring survivorship, fecundity and time of reproduction, which represent adaptive traits that enable a species to deal with spatial and temporal variability of abiotic conditions. This study aimed to compare reproductive traits associated to life-history theory for three Hyphessobrycon species from two lentic environments (four natural oxbow lakes and a man-made reservoir) of Mogi Guaçu River, upper Paraná River basin. METHODS: Specimens were collected with four minnow traps between August 2005 and July 2006 to cover dry and wet seasons (three samples in each season, and three samples in each environment). RESULTS: Reproductive strategy of H. bifasciatus and H. eques, which predominated in the oxbow lakes, differed from H. anisitsi in the reservoir. Hyphessobrycon bifasciatus and H. eques were single spawners with lower fecundity and size at sexual maturity, but invested more in number of eggs per body gram, while H. anisitsi was a multiple spawner species with higher fecundity, larger size at sexual maturity and body size. CONCLUSIONS: In seasonal environments, single spawners are synchronized with the floods to maximize juvenile survivorship, while reservoirs harbors multiple spawners’ fish due to the reduced fluctuation between high and low floods resulting from dam operation. Therefore, the seasonal condition in the oxbow lakes due to the flood pulse favored single spawners’ tactic, as showed by H. bifasciatus and H. eques. In contrast, the multiple spawning of H. anisitsi seems to be related to the more stable environmental condition throughout the year provided by the dam. Life-histories reported herein to Hyphessobrycon species must be common to other characid fishes inhabiting similar environments.


2021 ◽  
Author(s):  
Jae Young Choi ◽  
Liliia R Abdulkina ◽  
Jun Yin ◽  
Inna B Chastukhina ◽  
John T Lovell ◽  
...  

Abstract Telomeres are highly repetitive DNA sequences found at the ends of chromosomes that protect the chromosomes from deterioration during cell division. Here, using whole genome re-sequencing and terminal restriction fragment assays, we found substantial natural intraspecific variation in telomere length in Arabidopsis thaliana, rice (Oryza sativa), and maize (Zea mays). Genome-wide association study (GWAS) mapping in A. thaliana identified 13 regions with GWAS-significant associations underlying telomere length variation, including a region that harbors the telomerase reverse transcriptase (TERT) gene. Population genomic analysis provided evidence for a selective sweep at the TERT region associated with longer telomeres. We found that telomere length is negatively correlated with flowering time variation not only in A. thaliana, but also in maize and rice, indicating a link between life history traits and chromosome integrity. Our results point to several possible reasons for this correlation, including the possibility that longer telomeres may be more adaptive in plants that have faster developmental rates (and therefore flower earlier). Our work suggests that chromosomal structure itself might be an adaptive trait associated with plant life history strategies.


2012 ◽  
Vol 26 (6) ◽  
pp. 1311-1329 ◽  
Author(s):  
Chiara Benvenuto ◽  
Sandrine Cheyppe-Buchmann ◽  
Gérald Bermond ◽  
Nicolas Ris ◽  
Xavier Fauvergue

2008 ◽  
Vol 18 (5) ◽  
pp. 363-367 ◽  
Author(s):  
Benoît Facon ◽  
Jean-Pierre Pointier ◽  
Philippe Jarne ◽  
Violette Sarda ◽  
Patrice David

Sign in / Sign up

Export Citation Format

Share Document