Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong

In their Policy Forum "Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong" (8 January p. 128-129), K.O. Winemiller et al. call for more 'sophisticated and holistic hydropower planning" in the Amazon, Congo and Mekong basins (1). This is indeed incredibly important, because as it is now these very complex ecosystems are being managed in a highly reductionist manner – a socio-environmental disaster is the natural future scenario of current actions. In Tropical dams: To build or not to build?" (29 January p. 456), P. Fearnside goes deeper in the matter by arguing that 'it is essential to face whether such a massive dam-building plan should exist', given its large and fundamentally irreversible environmental and social impacts and small regional benefits (2). With regards to the Amazon basin, the plan includes dams or dam cascades in virtually all large and most medium-size rivers (1–3). We think P. Fearnside poses a very important point that must not be overlooked, and here we present an additional reason for reconsidering this massive dam-building plan in the Amazon: the threat of putting Amazonian manatees (Trichechus inunguis) on a direct path to extinction in the wild.
Amazonian manatees are aquatic and range throughout lowland Amazon basin (4). In typical droughts, the lowland basin transforms into disconnected and shallow water bodies, so manatees take refuge in rias (naturally blocked river stretches) or large perennial lakes (5–7). While migrating to or within refuges, they are commonly hunted. In extreme droughts, when refuges become shallower, mass slaughtering occur – as in 1963, 2005 and 2010 (5, 6, pers. obs.).
Once abundant (8), after 200 years of commercial slaughter this slow-breeding mammal (9) suffered a population collapse (10) and is now vulnerable to extinction (4). Current threats include habitat loss and degradation, climate change, increasing calf mortality and hunting that sometimes involves new and sophisticated techniques (4).
If implemented, the massive dam-building plan would partition the species into many small and confined populations. Each small population would suffer from inbreeding, loss of evolutionary potential (11) and increased vulnerability to slaughter, especially during natural or dam-induced extreme droughts. The dynamics of flooding would be substantially controlled by the dams, and it is unreasonable to assume that biodiversity would be favored over energy production in years of extreme droughts or floods. Overall, habitat deterioration would hugely intensify (12), further impacting manatee survival. It is not hard to see that this would create a perfect setting for pervasive local extinctions of the small and confined Amazonian manatee populations. The natural outcome would be a second species-level population collapse, from which recovery would be unlikely given that local socio-economic-environmental conditions will also have deteriorated further.
The Amazon without the iconic Amazonian manatee is as the Arctic without Polar bears or Savannas without African lions. The pursuit of economic growth by South America in general, and Brazil in particular, should not come at the expense of the extinction of the Amazonian manatee. More broadly, it is imperative and urgent to discuss ways of developing the region that appreciate the myriad values (monetary and non-monetary) of one of the greatest natural treasures that still exist on our planet.

References and Notes:
1. K. O. Winemiller et al., Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong. Science 351, 128–129 (2016).
2. P. M. Fearnside, Environmental and Social Impacts of Hydroelectric Dams in Brazilian Amazonia: Implications for the Aluminum Industry. World Dev. 77, 48–65 (2016).
3. Brazil, Programa para Aceleração do Crescimento - PAC-II, Eixo Energia (Program for the Acceleration of Growth, Energy Component). Federal Government, Ministry of Planning (2016), (available at http://www.pac.gov.br/infraestrutura-energetica).
4. M. Marmontel, "Trichechus inunguis. The IUCN Red List of Threatened Species. Version 2008. www.iucnredlist.org. Accessed 10 January 2016." (2008), (available at www.iucnredlist.org).
5. J. Thornback, M. Jenkins, THE lUCN MAMMAL RED DATA BOOk Part 1: Threatened mammalian taxa of the Americas and the Australasian zoogeographic region (excluding Cetacea) (The International Union for Conservation of Nature (IUCN) and United Nations Environment Program (UNEP), Gland, Switzerland, 1982; https://portals.iucn.org/library/node/5841).
6. E. M. Arraut et al., The lesser of two evils: seasonal migrations of Amazonian manatees in the Western Amazon. J. Zool. 280, 247–256 (2010).
7. M. Marmontel, M. G. Guterres, A. C. O. Meirelles, J. Calvimontes, F. Rosas, paper presented in the X Reunión de Trabajo de Especialistas en Mamíferos Acuáticos y 4o Congreso de la Sociedad Latinoamericana de Especialistas em Mamiferos Acuaticos, Valdivia, Chile, 2002.
8. C. Acuña, Nuevo descubrimiento del Gran Rio de Las Amazonas. Imprensa do Reino, Madri, 1641).
9. F. C. W. Rosas, Biology, conservation and status of the Amazonian manatee Trichechus inunguis. Mamm. Rev. 24, 49–59 (1994).
10. D. P. Domning, Commercial exploitation of manatees Trichechus in Brazil c. 1785–1973. Biol Conserv. 22, 101–126 (1982).
11. R. Frankham, C. J. A. Bradshaw, B. W. Brook, Genetics in conservation management: Revised recommendations for the 50/500 rules, Red List criteria and population viability analyses. Biol. Conserv. 170, 56–63 (2014).
12. W. J. Junk, Current state of knowledge regarding South America wetlands and their future under global climate change. Aquat. Sci. 75, 113–131 (2013).

In their article "Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong" (Science 351, 128-129; 2014), Winemiller et al. reported a total of 37 proposals of hydropower projects to be build in Peru. However, at least 18 (18037 MW) are projects: without feasibility studies (n=8), flooded by others hydropower dams (n=4), are the same project (n=4) and, unfeasible projects because are located in natural protected areas where there is not allowed to modify the landscape (n=2) (1-3). Nevertheless, this total could be higher considering projects with definitive concession or expected to be build in some years according to National Grid Operator (COES), but dismissed due to technical or socio-environmental infeasibility (2, 4-7). It is important to difference between political statements or investment promotion of hydropower projects from feasible projects. I suggest a careful analysis comparing data bases from non-governmental organisms with other sources (government, grid operator, etc.)
Peruvian electricity was mainly generated by hydropower in 2000 (81 %). Nowadays, is generated mainly by natural gas (50 % in 2014) (8). The decrease in new hydropower projects is due to the promotion of natural gas use (9) and a moratorium of new hydropower projects (10) by national government, mandatory deadlines to owners of new projects under penalty or denied of electrical concession and the necessity to adequate projects to comply with regulation to conserve environment and cultural heritage (11).
Finally, many proposed projects in Peru are located in high Andes, with small reservoir and high head. Therefore costs of lost fisheries, agriculture, and property suggested by the authors must be carefully evaluated for the Peruvian geography.
References and Notes:
1. Ministerio de Energía y Minas www.minem.gob.pe
2. Derecho, Ambiente y Recursos Naturales, Buscando la gobernanza energética en el Perú (Derecho, Ambiente y Recursos Naturales, Lima, 2011).
3. Consorcio Lahmeyer-Salzgitter, "Evaluación del potencial hidroeléctrico nacional "(Dirección General de Electricidad, Ministerio de Energía y Minas, República del Perú, Lima, 1980) http://www.minem.gob.pe/_detalle.php?idSector=6&idTitular=1801&idMenu=su...
4. Comité de Operación Económica del Sistema Eléctrico Interconectado Nacional COES, "Informe de Diagnóstico de las Condiciones Operativas del SEIN 2017 -2026" (Comité de Operación Económica del Sistema Eléctrico Interconectado Nacional, 2015; http://portal.coes.org.pe/planificacion/plantrasmision/WebPages/act2017-...
5. Inambari project http://www.minem.gob.pe/minem/archivos/file/DGGAE/ARCHIVOS/estudios/RESO...
6. Tambo 40 project http://gestion.pe/noticia/1338556/odebrecht-se-aleja-tambo-40
7. San Gaban I http://busquedas.elperuano.com.pe/normaslegales/declaran-caduca-la-conce...
8. Ministerio de Energía y Minas. 2015. "Evolución de indicadores del sector eléctrico 1995 – 2015". Dirección General de Electricidad, Dirección de Estudios y Promoción Eléctrica. Lima.
9. Ley 27133, Decreto Supremo 107-2004-EF, Decreto Supremo 019-2004-EM, Decreto Supremo 041-2004-EM www.minem.gob.pe
10. Ley 26980, Ley 27133, Ley 27239 www.minem.gob.pe
11. Decreto Ley 25844, Decreto Supremo 009-93-EM www.minem.gob.pe

Biodiversity loss can occur directly or indirectly in the medium and long term due to hydropower installation and operation. As Winemiller et al. (2016) highlight, large dams delay and attenuate seasonal flood pulses. The alterations in the flood pulse modify the range of water to regions that seasonally flood, in time and space. Many species have been adapting for thousands of years living in this periodic cycle of flooding and dry season, and species occupy niches from different flood plain regions. Mollusks have adapted to live in terrestrial and aquatic ecosystems by drastically decreasing their metabolism, with aestivation in response to dry periods. Birds annually feed and breed in areas periodically flooded, and seedlings are adapted to be submerged for several months in the wet season, among countless others examples. Each flood plain system has specific features influenced by the flood pulse of rivers and lakes, which promotes environmental heterogeneity and has been associated to higher or lower diversity. Aquatic diversity can influence community resilience, which is important information for determining how the impacts of the flood pulse change, but long-term ecological research is necessary to obtain this data. Furthermore, some flood plain regions have scarce data from local diversity. According Dittrich et al. (2016), local diversity is the main information for management and conservation of the floodplain community. So changes in the flood pulse automatically induce biodiversity loss and reduce the populations in the medium and long term, due to new adaptations that the species will be required to make in order to live in new environmental conditions. In this way, in addition to recommendations suggested by Winemiller et al. (2015), the behavior and distribution of the biota in flooded plain regions have to be considered before authorization of the installation and operation of hydropower.

In their important paper published in Science, vol. 351, issue 6269 pp. 128-129, Winemiller K.O. et al gave a very good summary of the impact of dam construction in the three basins on fish biodiversity However, the construction of dams in the Amazon, Congo and Mekong basins affects not only fish biodiversity but also the hydrosocial cycle, that is the hydrological dynamics, the human activities in connection with the biodiversity of terrestrial and aquatic ecosystems. This was demonstrated by the Amazon Basin (1) but is most probable valid for the Mekong and Congo basins.
Deforestation that occurs with reservoir construction also affects fish biodiversity and the ecological dynamics of the aquatic ecosystems such as creeks, lakes and wetlands. (2)
The present plans to develop the Amazon, Congo and Mekong Rivers with the construction of several reservoirs, as shown by the authors will introduce a large scale change in the hydrological cycle in the hydrosocial cycle and ecosystem services that are key to the maintenance of evolutive and biodiversity processes (3).
Besides the overall impact in the aquatic and terrestrial ecosystems construction of Amazonian reservoirs results in the emissions of greenhouse gases affecting aquatic biodiversity and fish biodiversity downstream the reservoirs.(4,5) Greenhouse gases may also be produced in the Congo and Mekong basin reservoirs.
For the Amazonian reservoirs there are another threats not described by the authors: there are 150 new dams planned for the six major tributaries of the Amazon in the Andes. Peru, Ecuador, Bolivia and Colombia are building up already 55 dams for hydroelectricity in the Andean Amazon (6). Besides the river fragmentation caused by these dams there is strong interference of the connectivity that links the Andean headwaters with the lowland Amazon, also affecting fish migration, fish biodiversity and sediment transportation. This will affect aquatic biodiversity, habitat integrity, food chains and biogeochemical cycles downstream.
Some further recommendations for planning and conservations of the basins: several rivers are active centers of evolution (7). They should be fully protected of reservoir construction and maintained as permanent evolutive hotspots (8); the interaction of engineering techniques with ecohydrological principles are also fundamental: less inundated areas with smaller reservoirs and low retention times;
avoiding large reservoir cascades maintaining stretches of rivers free of reservoirs enhancing the recovery of the biodiversity and the fluvial ecological dynamics.
An optimization of dam construction should include planning for protecting fish diversity, maintaining habitat integrity as pointed out by the authors. The management of competing objectives includes a important question: the challenge is where and how hydropower is built up. As pointed out in (9) the fundamentals are the scientific understanding of the relationship between ecosystem services and hydropower benefits. This is strategic in a long term policy. Planning, engineering procedures, ecohydrological principles and limnological/ecological approaches are not incompatible (10).
Reservoir construction around the world has been improved considerably in the last 20 years thanks to the accumulated scientific knowledge of reservoir research. Therefore new technologies for reservoir construction should be included earlier in the planning stage in the three basins, in order to mitigate impacts, optimize operations for hydropower production, maintaining connectivity of streams, lakes with the river downstream the reservoir, and suplying adequate water quality with positive impact on fish biodiversity downstream (11,12).

References

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11) Stone R, 2011. Science. 333 pp. 814-818.
12) Tundisi, J.G. and Straskraba M., 1999. Theoretical reservoir ecology and its applications. Backhuys Publications, Brazilian Academy of Sciencees. 585 pp.