I***i
发帖数: 14557 | 1 http://www.wired.com/wiredscience/2012/12/panama-bug-count/
6,000 Insect Species Found in One Acre of Rainforest
（It took an army of committed scientists to get an accurate count of all
the arthropods in the San Lorenzo forest. Image: Jurgen Schmidl/University
of Erlangen）
A sweeping census involving more than 100 scientists and lasting almost a
decade has estimated that Panama’s San Lorenzo forest is home to an
estimated 25,246 arthropod species. The study is the most extensive survey
of insects, spiders, and their relatives ever undertaken and should help
researchers get a better understanding of what factors influence
biodiversity.
“This is the first time that diversity of all types of arthropods has been
quantified from a tropical rainforest,” says ecologist Tomas Roslin of the
University of Helsinki, an author of the new paper.
Arthropods, which include insects and spiders, are the most diverse and
numerous phylum on the planet, and researchers have struggled to quantify
their abundance and diversity because of their small size, frequent
movements, and inaccessible habitats. The lack of data on arthropods has
made it difficult to get a handle on the total number of species on the
planet and to track the effect of human activities on this number.
“Given the difficulties involved in both collecting and identifying the
bugs, most previous researchers have focused on one or a few groups of
arthropods,” says Yves Basset of the Smithsonian Tropical Research
Institute in Panama City, who is another ecologist involved in the new work.
“Generalizing from such limited samples is very tricky.”
To get a more complete view of arthropod abundance, scientists involved in
the new effort used 14 different techniques to collect bugs in the San
Lorenzo Forest, including picking beetles out of dead wood on the rainforest
floor, climbing tree trunks and deploying helium balloons to reach the
forest canopy and pluck high-dwelling insects off branches, and fogging
trees with insecticides to catch the flying bugs. The collection methods
were repeated during three distinct seasons of the year in 12 20-by-20
square meter plots. In all, the team collected 129,494 arthropods, compared
with only a few thousand in most previous studies, then spent the next 8
years identifying and sorting the bugs.
In the 0.48 hectares directly studied, the researchers found 6144 arthropod
species. By extrapolating out to the rest of the 6000 to hectare forest,
they estimate that the San Lorenzo Forest contains about 25,000 arthropod
species, 60% to 70% of which are likely to be previously unknown. (In this
study, researchers didn’t attempt to fully describe or name new species,
instead grouping unknown organisms by the basic characteristics needed for
the sake of the count.) Any given hectare contains about 60% of the species
found in the whole forest, the team reports online today in Science.
“That’s very clearly good news,” Roslin says, “because it means that to
count the species of a tropical rainforest you don’t have to sample
gigantic areas.”
Additionally, the team concluded that the overall number of arthropod
species closely reflected the species richness of plants, suggesting that
counts of plant species can give scientists a sense of the arthropod
diversity.
Terry Erwin, an entomologist at the Smithsonian Institution’s National
Museum of Natural History in Washington, D.C., who was not involved in the
study, cautions against putting too much weight on the estimated number of
species. “This study is exciting because they’ve taken a large team of
people and used every technique available,” he says. “But to take a little
sample from one place and scale up, it’s been critiqued and critiqued and
it just doesn’t work.” Erwin adds that further surveys of the tree
diversity across the entire San Lorenzo rainforest could help make better
predictions of the total number of arthropod species there.
For now, the results can help scientists determine additional factors that
influence biodiversity and develop models of the impact of habitat loss on
arthropod diversity and abundance, Basset says. With this baseline count,
and the calculated ratios between types of organisms, researchers can begin
to assess how adding or removing one particular area or type of tree or
animal affects this balance and can then begin to set conservation
priorities. “If we want to understand and conserve life on Earth, we had
better start understanding and conserving the arthropods of tropical forests
.” | k**********i
发帖数: 8706 | | e****o
发帖数: 3844 | 3 之前就听说中南美洲交接处物种极大丰富，我还一直想去Costa rica看动物——昆虫就
免了，这玩意儿好多都是会飞的大虫子……
【在 I***i 的大作中提到】
: http://www.wired.com/wiredscience/2012/12/panama-bug-count/
: 6,000 Insect Species Found in One Acre of Rainforest
: （It took an army of committed scientists to get an accurate count of all
: the arthropods in the San Lorenzo forest. Image: Jurgen Schmidl/University
: of Erlangen）
: A sweeping census involving more than 100 scientists and lasting almost a
: decade has estimated that Panama’s San Lorenzo forest is home to an
: estimated 25,246 arthropod species. The study is the most extensive survey
: of insects, spiders, and their relatives ever undertaken and should help
: researchers get a better understanding of what factors influence
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