Untangling the jungle

A new study uses comprehensive sampling and species identification to uncover the full species richness of a rain forest.

Untangling the jungle

Most multicellular species on earth are arthropods living in tropical forests. Yet, given the difficulties involved in counting them, we know very little about their exact numbers – even at the scale of a single forest.

Now, an international team of scientists have uncovered the full species richness of a Panamanian rain forest.

– We crawled, climbed and sifted through a tropical forest of 60 km2, says Tomas Roslin of the University of Helsinki, one of the authors of the study.

Previous efforts to estimate arthropod diversity have focused on a limited number of species and used only a few methods of sampling.

– In this study, we went all out and sampled all sorts of arthropods from the soil to the canopy in as many ways as we could, says Roslin.

To do this, a total of 102 researchers from 21 countries worked together. The field team first sampled the rainforest canopy from cranes, inflatable platforms, balloons, climbing ropes, as well as crawling along the forest floor to sift soil and trap and bait arthropods. This massive effort was estimated to have required 70 person-years. However, the largest effort lay in sorting and identifying the nearly 130,000 arthropods found.

The findings from the twelve different sampling sites led the researchers to estimate that the full forest will harbor some 25,000 arthropod species.

– This is a high number, as it implies that for every species of bird or mammal in this well-studied forest, you will find approximately 83 and 312 species of arthropods, respectively, explains Roslin. Hence, if we are interested in conserving the diversity of life on Earth for the future, we should start thinking about how best to conserve arthropods.

The species richness of arthropods was found to closely mirror the species richness of plants.

– From a conservation point of view, this means that we can save a good deal of arthropods by focusing conservation efforts on floristically rich sites, says Roslin.

Roslin stresses that the current findings were only made possible by a massive collaborative effort between experts of different expert groups.

– We humans assign immense resources to mapping our genes and resolving sub-atomic structures, but invest so much less in exploring those organisms with whom we share the Earth. Why such research should be run on a shoe string escapes me, says Roslin.

Tomas Roslin in the research database Tuhat »»

Faculty of Agriculture and Forestry »»

Text: Katja Bargum
Photo: Maurice Leponce
University of Helsinki, digital communications

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