Measuring at 14 centimeters (5.5 inches), a new spider discovered in the sand dunes of Israel is the largest of its kind in all of the Middle East. How it avoided detection until now in one of the world' longest inhabited—and explored—regions is likely due, at least in part, to the species' entire habitat consisting of only three square kilometers.

Dwelling in the Sands of Samar in the southern Arava region of Israel, the spider, called Cerbalus aravensis, is already greatly endangered due to development plans. Rezoning for agriculture and sand quarries has already reduced the spiders' dunes by more than half: from seven square kilometers to three.

"The discovery of this new spider illustrates our obligation to preserve the dune," says Dr. Shanas from the University of Haifa, who headed the team of scientists.

The habitat is under direct threat as the Israel Land Administration is moving ahead to renew mining projects in the Sands of Samar. Shanas says that the spider may not be the only species hiding from science for millennia among the dunes and that they should be preserved for their biological richness.

"The new discovery shows how much we still have to investigate, and that there are likely to be many more species that are unknown to us. If we do not preserve the few habitats that remain for these species, they will become extinct before we can even discover them," Dr. Shanas concludes.

Little is known about the spider's biology, but researchers say it is nocturnal and active during the hottest months. The species lives in an underground den covered over by a door of glued together sand particles.

Taken from: www.mongabay.com

First comprehensive study of insect endangerment: ten percent of dragonflies threatened

A lot of time, effort, and funds have been spent on programs evaluating the threat of extinction to species around the world. Yet insects have not benefited from these programs, which have largely focused on more 'charismatic' species such as mammals, birds, amphibians, and reptiles. This gap is clearly shown by the fact that 42 percent of vertebrates have been assessed by the International Union for the Conservation of Nature (IUCN), and only 0.3 percent of invertebrates.

Given this dearth of knowledge regarding the threat level of extinction to invertebrates, conservationists concerned about the current extinction crisis have largely had to do without hard data on insects and other invertebrates to make predictions regarding the level of extinction possible.

A new study in Biological Conservation has begun the long and difficult process of evaluating the state of insect populations around the globe, focusing on the order of Odonata, which includes dragonflies and damselflies.

Assessing the threat

Viola Clausnitzer, one of the paper’s lead authors, told mongabay.com that assessing the Odonata order was a natural choice to begin this process.

"Odonata are an easy to study group: they are active at daytime, have a striking appearance and courtship behavior, the taxonomy is more or less solved (unlike most other insect groups), they are used as indicator organisms for assessments, they can serve as flag-ship species for environmental health ('guardians of the watershed')," Clausnitzer said, a geographer at the Phillips University of Marburg, Germany. "For most other insect groups a global approach is not yet possible because of problems with taxonomy and too many yet undescribed species."

To determine the overall threat level to dragonflies and damselflies, researchers assessed individual threat levels for 1,500 randomly selected species out of the total 5,680 described Odonata species (26.5 percent). Clausnitzer and her team assessed threat status by looking at the availability and state of habitat within each species' range.



Researchers were surprised to find that only 10 percent of these species appeared to be under threat of extinction. This was a better than expected, especially considering that 31 percent of amphibians, 20 percent of mammals, and 12 percent of birds are threatened.

The highest ratio of threatened Odonata species were found in Australia and islands off Southeast Asia. Australian species are increasingly threatened by climate change’s affect on freshwater environments, while island dragonflies and damselflies face constricted habitats and deforestation. To date only two Odonata species has been recorded going extinct in modern times, both on islands: Megalagrion jugorum from Maui and Sympetrum dilatatum from Saint Helena.

Data Deficient

In addition to 10 percent of dragonflies and damselflies considered threatened, the researchers also found that 35 percent, or 527 species, were classified as Data Deficient. In other words, the scientists simply did not have enough information on the species to make determination of their status.

The higher the Data Deficient category the poorer the results," Clausnitzer admits. "But the percentage of Data Deficient species was equally high in the global amphibian assessment and is only lower with birds and mammals. Nevertheless much effort is needed to lower the number of Data Deficient species."

While the percentage of Data Deficient species is relatively high for vertebrates, Clausnitzer says that it is unique for invertebrates.

"If you assess other groups [of invertebrates, the percentage of Data Deficient] will be much higher. Still, the data deficient areas are tropical countries and much more surveys, ecological and biodiversity field work and taxonomica work is necessary to lower the Data Deficient category," Clausnitzer says. Nearly 60 percent of the world's Odonata species live in the Neotropics and the Indo-Malayan realms.

According to the paper, the percentage of Data Deficient species could raise the number of threatened Odonata species to approximately fifteen percent, rather than ten, but this is still only half the number of threatened amphibians.

These findings call into question predictions of the current extinction crisis that tend toward the higher end. For example, even if fifteen percent of Odonata species are threatened it is difficult to imagine an extinction crisis that exceeds this percentage if other insect species are similar.

This delicate damselfly was assessed as Data Deficient (DD) on the IUCN Red List, because it was known from only a few males from two localities close to each other in the Amazon forest of northern Peru. During a visit to the Research Station of Tiputini, located in eastern Ecuador this last January, R. W. Garrison and Natalia von Ellenrieder found it also inhabiting several narrow streams within the Ecuadorian forest. This discovery considerably enlarges the range of distribution of this beautiful damselfly, and hopefully many other rare species of Odonates which are insufficiently known are found more widely distributed upon further search of this vast and rich forest. The adults fly very close to the water surface, and perch horizontally on sticks and leaves overhanging the water. In the shaded streams they are rendered inconspicuous, and can usually be noticed only after examination of the vegetation growing along the stream banks. Text credit: Natalia von Ellenrieder. Photo by: Rosser W. Garrison.

"Some of the predictions seem to be largely exaggerated," Clausnitzer says, adding that "insects can survive in small pockets of habitats."

In addition dragonflies and damselflies do not face the same hunting pressures as many mammals, birds, reptiles, and amphibians. The bushmeat and wildlife trafficking has become one of the leading causes behind species endangerment worldwide, but it is a threat that insects, other than butterflies, have avoided.

Conservation and research

Although not as media-friendly as polar bears and pandas, Clausnitzer believes that conserving dragonflies and damselflies is important to saving ecosystems in general.

"Odonata are key-predators and are sensitive to changes to the aquatic and terrestrial environment. Because they are easy to observe and survey they are excellent indicator organisms to monitor environmental health. Since most people know dragonflies, they are good flag-ship species to teach people about the importance of conservation and monitoring. Thus dragonflies can be regarded as 'guardians of the watershed'," Clausnitzer says.

To conserve these 'guardians'—and the ecosystems they inhabit—Clausnitzer urges "serious global attempts to protect forests, springs, streams and rivers. In Europe we can currently watch an increase in water quality, while third world countries, which often rely directly on river water, have a drastic decrease in water quality and availability. For example it would help to have a 10m wide strip along streams and rivers, which remains untouched."

Still, there is a lot more research and work that needs to be done. "Odonata only comprise a small invertebrate order, with above-average dispersal ability and relatively wide distribution ranges," Clausnitzer and the other authors write in the paper. "For conservation science and policy to be truly representative of global biodiversity a representative cross-section of invertebrates needs to be included."

What insect orders would they recommend next?

"In terms of feasibility grasshoppers and butterflies might be possible," Clausnitzer said. "But more important would be an assessment of hymenoptera, since these play an important role in pollination and as predators of pest-insects (key ecosystem-services)."

Hymenoptera is a large order of insects, comprising everything from bees and ants to sawflies and wasps.

Clausnitzer says that in order to move forward there needs to be "funding for more surveys, field work and taxonomic work," adding that, "nevertheless with the current economic situation it is even more difficult to get funding for basic biodiversity research."

If scientists are ever to make accurate estimates regarding the extinction crisis already under way, more research will be necessary.


Taken from:

Mongabay.com