Dispute over size of population: researchers disagree with supposedly rising Orang-Utan Numbers

It sounded like a great success in the fight for the preservation of endangered species: Recently the government of Indonesia reported that the Orang-Utan populations in your country would have recovered. More than ten percent of the Population of apes has increased from 2015 to 2017, it said in a report. In nine areas of the Population from 2015 to 2016, have more than doubled: from 1153 to 2451 animals.

However, this Trend researchers have objected to now. Still, stocks fell quickly, writing experts from several countries in the journal "Current Biology".

The government's representation is contrary to recent research results, the scientists to Maria Voigt from the Max-Planck-Institute for evolutionary anthropology in Leipzig, Germany.

Junior arrives every six to seven years

a 2018 published investigation showed that the stocks on Borneo, where most orangutans live, had fallen from 1999 to 2015 to more than 100,000 animals. That Orang-Utan-stocks to double in a single year, is already biologically impossible: Orang-Utans get, according to Voigt, on average, only every six to seven years, a descendant.

PHOTO by Tim Laman/ Wildlife Photographer of the Year 2016 Excellent animal photos, tops striker

Generally speaking, there are three types of Orang-Utans, all of which are regarded as Mobilbahis threatened with extinction: From the Borneo-Orang-Utan (Pongo pygmaeus) live, according to Voigt are still 70,000 to 100,000 animals, the Sumatran Orang-Utan (Pongo abelii) around 14,000 and only last year discovered Tapanuli-Orang-Utan (Pongo tapanuliensis), which is also located on the island of Sumatra, about 800. In view of the continuous decline of forests, the researchers assume that the stocks will fall on the island of Sumatra by 2020 11 to 27 percent.

extinction

threatened "All three species of Orang-Utans are threatened with extinction," Co-author Erik Meijaard from the world conservation Union (IUCN), cited in a communication from the magazine. Accordingly, the government evaluated areas based on five percent of the orangutan habitats and exclusively on protected areas, although most of the people lived apes outside of protected zones. The particularly rare Tapanuli-type was not included in the report.

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"is It manufactures scientifically unfair to transfer population trends from these areas to the entire area of all three types," stress the researchers. The researchers themselves collected data were much more reliable, says Voigt: "We have sampled the entire distribution area, over a much greater period of time." The main threat to the animals - in addition to targeted killings - the Shrinking of their habitat due to the forest loss. At the moment they are built in the territory of the Tapanuli-Orang-Utans a dam.

The research team also doubts the government's claim, several other endangered species have also increased - for example, the Sumatran rhinoceros (Dicerorhinus sumatrensis). "We urge the Indonesian government to review the methods for the assessment of their conservation efforts, as they describe the current reality."

joe/dpa

Date Of Update: 07 November 2018, 08:00