WWF Paraguay’s on the Pilcomayo River Situation
For many years, the Paraguayan Chaco region has been enduring regularly the same fish and caiman mortality phenomena in the Pilcomayo River area. We must remember that the Pilcomayo River is a wandering water course which starts in Bolivia with a fast river of water which becomes unpredictable as it reaches the great plain of the Chaco. The magnitude of these effects depends on the weather conditions in the Chaco: “El Niño” with constant and torrential rain o “La Niña” with prolonged drought. This cycle is aggravated by the biggest environmental challenge of the planet, “global warming”, which is already becoming apparent as a consequence of human activities. To all this elements, we must add man’s intervention and manipulation of the river system by diverting its water flows and in some cases creating small dams for local benefits, damaging life located downstream.
In Paraguay, there are three species of caiman: The Paraguayan caiman (Caiman yacare), the most common and widespread of the three species; the broad-snouted caiman (Caiman latirostris) found in the Oriental Region and in the southern Chaco; and the dwarf caiman (Paleosuchus palpebrosus) found in the Apa River Basin, and which is not abundant in Paraguay. The broad-snouted caiman is currently in danger of extinction in Paraguay.
The Paraguayan caiman is very abundant in the Chaco Region and in the southern Paraguay River. It is absent from the dry Chaco and the eastern part of the Oriental Region of Paraguay. This caiman feeds, depending on its age and size, on insects, mollusks, crustaceans, frogs, fishes and other small animals. All of these prey species are abundant in the Pilcomayo area; nevertheless, the big droughts affect their population densities, and thus produce a decline in the caiman food supply. The broad-snouted caiman, besides feeding on the same prey as the Paraguayan caiman, also feeds on other vertebrates, such as birds and small mammals. When the environment becomes too dry, both species tend to leave the water and seek refuge in nearby forests in order to wait out the dry period.
The most important issue for the conservation of the caiman and other wildlife species is the protection of its habitats: water courses, wetlands and forests. Currently, our country is suffering the severe consequences of land use changes, owing to a great increase in lands devoted to agriculture and livestock production. Millions of hectares of Atlantic Forest have been destroyed in the Oriental Region in order to allow the implementation of various agricultural initiatives. In the Chaco, although deforestation can be done under a SEAM permit, there is not an effective monitoring system, as it is estimated that more than 80% of the producers do not have the required environmental license. In the Eastern Region, local extinctions of the broad-snouted caiman can already be seen, and it is endangered throughout its area of distribution. The massive mortality of the Paraguayan caiman population in the Pilcomayo River area a direct result of the manipulation of the Pilcomayo River for livestock and agriculture.
Cyclically, approximately each decade, we regret the condition of the animals in the Pilcomayo River, and, as time passes by, we forget what we learned in the years before: all of this happens because of the destruction of the habitats of all wildlife species. As we focus on caiman, we must also remember that they are part of a complicated food web; as top predators, they affect the population densities of many other species.
The caiman is an animal that suffers from extreme environmental conditions, and many die during droughts, but it is better adapted to these conditions than human beings. Relocating caiman to other places is not responsible; doing so only puts additional stress on the resident caiman population, often producing an overpopulation that cannot be maintained on the available resources. Some of the resident animals have already moved into the forests, some others stay close to the water, and a translocation of more caiman will affect their stress levels even more.
As everyone benefits from natural resources, we are all responsible to maintain them and take care of them. We are also the agents of their destruction, some from the consequences of direct actions, others because they don’t meet their obligations, stealing the future of their children with corrupt acts. Others are culpable because they don’t demand the enforcement of environmental protections, do not get committed and involved, and don’t use a strong and brave voice to defend the natural resources.
WWF-Paraguay Country office