first_imgAn extreme drought in 2005 decreased many freshwater fish species abundance in areas like Lago Catalão, and many haven’t recovered yet.Drought overturned the ecology of the lake over time – big fish populations declined while little fish boomed.The shift has direct impacts on diets in the region since many local people depend on fish for protein, meaning that climate change is already influencing food reserves here. Life beneath the waters of the Amazon is probably not the first thing that comes to mind when you think of the world’s largest rainforest. All of the bright, primary colors direct your eyes aboveground. But beneath the murky waters of the Amazon swims the highest diversity of freshwater fish on Earth. This stunning diversity may be “out of sight, out of mind” for most, but not for Dr. Kirk Winemiller from Texas A&M AgriLife Research and his Brazilian colleagues. The muddy waters of the Amazon river hold the highest freshwater fish diversity in the world. Amazon floodplains house important fish species but, climate change is increasing the intensity and frequency of floods and droughts in these systems. This could have dramatic effects on fish populations. Photo credit: Rhett ButlerInvestigating long-term data from a floodplain lake near the confluence of the Amazon and Negro rivers, Winemiller and his team found that fish populations drastically changed after a severe drought in 2005. And numbers of many species haven’t recovered since. Such changes are not only ecologically significant: fish are an important source of protein for people residing in these regions, and these life-sustaining fisheries are now imperiled by overfishing and climate change. Climate change is increasing drought intensity and frequency – and this is likely to impact freshwater fish populations in the Amazon and beyond.Changes in biodiversity directly affect “the lives of most organisms living in and around freshwater environments, including humans” said Dr. Cristhiana Röpke, the lead author of the paper from the Instituto Nacional de Pesquisas da Amazônia in Manaus, Brazil.Floods and droughtsRiver life in the Amazon is extreme. When precipitation levels are high during the rainy season, Amazonian floodplains fill. But when there is not enough water in the dry season, floodplains can suffer droughts. For large rivers like the Amazon, much of the cycling is dictated by how much rain falls on the headwaters.Kirk Winemiller and his Brazilian colleagues analyzed fish survey data collected from Lago Catalão in Manaus, Brazil. Lago Catalão is a floodplain lake located near the confluence of the Amazon and Negro Rivers. The flood cycle consists of four seasons: rising water, flooding, receding water, and drying. Photo credit: Cristhiana Röpke.Cycling between floods and droughts affects water connectivity and quality, species interactions, and primary production – an important ecological step where primary producer like plants make energy available through photosynthesis.Now, climate change is putting its stamp on this naturally occurring cycle, by shifting rainfall patterns and making these extreme events more frequent and intense. But climatic changes are also affecting headwaters differently. For instance, extreme floods are occurring more often in the headwaters of the Negro river, which is the second largest tributary of the Amazon river. The Madeira river – the largest tributary – has seen more extreme droughts. Many studies have focused on how changes in rainfall may affect forest dynamics in the tropics, but few studies look deeper, into the murky freshwater. Fish out of waterWinemiller and his Brazilian colleagues analyzed data from monthly surveys of freshwater fish conducted in Lago Catalão, a floodplain lake near the confluence of the Amazon and Negro rivers. Between 1999 and 2014, the surveys gathered detailed information about the fish, like species identity, primary food source, and size.With roughly 400 species sampled to date, Lago Catalão represents a large portion of the freshwater fish found in the Amazon floodplains. It is also important for tourism. However, there are minimal conservation efforts in the area, the largest of which are local initiatives for fisheries management. A dried up part of Lago Catalão, a floodplain lake located at the confluence of the Amazon and Negro rivers. Photo credit: Daniele Campos.In 2005, the region suffered a severe drought, during which 70 percent of the floodplain lakes dried up. This is a view of a channel connecting Lago Catalão with the Negro River in October 2005. Photo credit: Sidinéia AmadioThe study shows that rainfall patterns have important direct and indirect effects on lake ecology. Indirectly, droughts may cause shifts in what fish are consuming, causing trickle-down changes throughout the ecosystem. Seasonal water changes determine when the floodplain lake is connected to both rivers. Sometimes it can be completely cut off. In October 2005, an intense drought dried up 70 percent of the floodplain habitats in this region. Lago Catalão was disconnected from the Negro river for about three months.After the drought, fish populations dramatically changed. But not every change occurred immediately. This suggests that intrinsic biological factors – like reproduction, range, and diet – changed as well. Currently, many fish species are less abundant in the floodplain lake than before the drought, including many large fish species that are important for human consumption. The team found hundreds of dead fish near the dried regions of the floodplain lake. Photo credit: Sergio Santorelli.Declines in large fish may be a result of an inability to migrate from river to lake. On the other hand, the study found that small fish that reproduce quicker are now higher in abundance than before the drought. One example is the tambaqui (Colossoma macropomum),a seed and fruit eating giant that weighs up to 88 pounds. Tambaqui is a migratory species that declined after the drought. The year before the drought, the catch per unit efficiency (CPUE) – a measure of abundance for fish – of tambaqui was approximately 0.035. After the drought, this declined to approximately 0.0025 – more than a 90 percent drop from the pre-drought CPUE. Unfortunately, this species is also important to local fish markets and has a high-market value.In contrast, the study found only small changes in the abundance of primary consumers, i.e. fish that rely on only plant material as their food source. However, omnivores and secondary consumers – fish that rely on animals like insects or other fish – markedly declined. Fishing in troubled watersDespite the importance of fish for local consumption, many species with consumer value are overexploited, and are not successfully farmed. “Our study found that some of the most affected fish species were also the ones that were valuable in local fish markets. Therefore, climate change in the Amazon region likely will influence fisheries,” explained Winemiller. As climate change increases the intensity and frequency of droughts, these effects could worsen over time. During droughts, fishermen catch more fish. More droughts may lead to more overexploitation. And this would be on top of the declines already seen in this study. As the research shows, this can greatly affect the lake’s ecology and the resilience of the fish communities as a whole. Each fish species fulfills a different role in the community. They may eat different food, reproduce at different times, and live in different parts of the lake. If a specific role is taken away it may not be filled as quickly – or at all – after extreme events.“Reduced supply of fish would possibly result in starvation and migration of these people to other areas,” said Röpke.In the shallow portions of the floodplain lake, riverine people reside in floating houses. These people rely on freshwater fish as their primary source of protein. Photo credit: Thatyla Beck FaragoShe added that the study highlighted the “need for protection areas in large rivers and floodplains because these areas could work as refuges for fish population preventing collapses and biodiversity loss under a scenario of increased frequency of drought.”Between the number of hooks in the water and prevalent drought conditions, the situation looks murky for Amazonian fish. The need for change is clear, even if the water is not. Citations: Röpke, C.P., Amadio, S., Zuanon, J., Ferreira, E.J.G., de Deus, C.P., Pires, T.H.S., Winemiller, K.O. (2017) Simultaneous abrupt shifts in hydrology and fish assemblage structure in a floodplain lake in the central Amazon. Scientific Reports, 7, 40170.doi: 10.1038/srep40170. Animals, Biodiversity, Climate Change, Conservation, Drought, Environment, Fish, Fishing, Food, Interns, Overfishing, Research, Rivers, Weather Popular in the CommunitySponsoredSponsoredOrangutan found tortured and decapitated prompts Indonesia probeEMGIES17 Jan, 2018We will never know the full extent of what this poor Orangutan went through before he died, the same must be done to this evil perpetrator(s) they don’t deserve the air that they breathe this has truly upset me and I wonder for the future for these wonderful creatures. So called ‘Mankind’ has a lot to answer for we are the only ones ruining this world I prefer animals to humans any day of the week.What makes community ecotourism succeed? In Madagascar, location, location, locationScissors1dOther countries should also learn and try to incorporateWhy you should care about the current wave of mass extinctions (commentary)Processor1 DecAfter all, there is no infinite anything in the whole galaxy!Infinite stupidity, right here on earth.The wildlife trade threatens people and animals alike (commentary)Anchor3dUnfortunately I feel The Chinese have no compassion for any living animal. They are a cruel country that as we knowneatbeverything that moves and do not humanily kill these poor animals and insects. They have no health and safety on their markets and they then contract these diseases. Maybe its karma maybe they should look at the way they live and stop using animals for all there so called remedies. DisgustingConservationists welcome China’s wildlife trade banThobolo27 JanChina has consistently been the worlds worst, “ Face of Evil “ in regards our planets flora and fauna survival. In some ways, this is nature trying to fight back. This ban is great, but the rest of the world just cannot allow it to be temporary, because history has demonstrated that once this coronavirus passes, they will in all likelihood, simply revert to been the planets worst Ecco Terrorists. Let’s simply not allow this to happen! How and why they have been able to degrade this planets iconic species, rape the planets rivers, oceans and forests, with apparent impunity, is just mind boggling! Please no more.Probing rural poachers in Africa: Why do they poach?Carrot3dOne day I feel like animals will be more scarce, and I agree with one of my friends, they said that poaching will take over the world, but I also hope notUpset about Amazon fires last year? Focus on deforestation this year (commentary)Bullhorn4dLies and more leisSponsoredSponsoredCoke is again the biggest culprit behind plastic waste in the PhilippinesGrapes7 NovOnce again the article blames companies for the actions of individuals. It is individuals that buy these products, it is individuals that dispose of them improperly. If we want to change it, we have to change, not just create bad guys to blame.Brazilian response to Bolsonaro policies and Amazon fires growsCar4 SepThank you for this excellent report. I feel overwhelmed by the ecocidal intent of the Bolsonaro government in the name of ‘developing’ their ‘God-given’ resources.U.S. allocates first of $30M in grants for forest conservation in SumatraPlanet4dcarrot hella thick ;)Melting Arctic sea ice may be altering winds, weather at equator: studyleftylarry30 JanThe Arctic sea ice seems to be recovering this winter as per the last 10-12 years, good news.Malaysia has the world’s highest deforestation rate, reveals Google forest mapBone27 Sep, 2018Who you’re trying to fool with selective data revelation?You can’t hide the truth if you show historical deforestation for all countries, especially in Europe from 1800s to this day. WorldBank has a good wholesome data on this.Mass tree planting along India’s Cauvery River has scientists worriedSurendra Nekkanti23 JanHi Mongabay. Good effort trying to be objective in this article. I would like to give a constructive feedback which could help in clearing things up.1. It is mentioned that planting trees in village common lands will have negative affects socially and ecologically. There is no need to even have to agree or disagree with it, because, you also mentioned the fact that Cauvery Calling aims to plant trees only in the private lands of the farmers. So, plantation in the common lands doesn’t come into the picture.2.I don’t see that the ecologists are totally against this project, but just they they have some concerns, mainly in terms of what species of trees will be planted. And because there was no direct communication between the ecologists and Isha Foundation, it was not possible for them to address the concerns. As you seem to have spoken with an Isha spokesperson, if you could connect the concerned parties, it would be great, because I see that the ecologists are genuinely interested in making sure things are done the right way.May we all come together and make things happen.Rare Amazon bush dogs caught on camera in BoliviaCarrot1 Feba very good iniciative to be fallowed by the ranchers all overSponsoredcenter_img Article published by Maria Salazarlast_img

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