These differences have been explained by a hypothesized north-south–oriented savanna corridor through the center of Sundaland that blocked dispersal of wet forest species ( 7– 13).
Despite this long history of land connections, there exists a marked biogeographic boundary between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland ( 3, 5, 6). The present-day insular nature of this region is unrepresentative of the historical situation because most of the time the area formed a single landmass as a result of lowered sea levels associated with global cooling events ( 2– 5). Together with the Amazon Basin, Congo Basin, and New Guinea, Southeast Asia's Sundaland forms one of the world's largest equatorial tropical forests ( 1). This finding makes it clear that proposed biogeographic explanations for plant and animal distributions within Sundaland, including possible migration routes for early humans, need to be reevaluated. However, we could not confirm the presence of a savanna corridor. These results strongly suggest that exposed sandy sea-bed soils acted as a dispersal barrier in central Sundaland. For drought tolerance, no such pattern was detected. Indicator taxa of clusters that occurred across Sundaland had significantly higher coarse-soil tolerance than did those from clusters that occurred east or west of central Sundaland. We found 11 terminal floristic clusters, 10 occurring in Borneo, 5 in Sumatra, and 3 in Peninsular Malaysia. We then identified the indicator genera for clusters that crossed the central Sundaland biogeographic boundary and those that did not cross and tested whether drought and coarse-soil tolerance of the indicator genera differed between them.
To test these two nonexclusive hypotheses, we performed a floristic cluster analysis based on 111 tree inventories from Peninsular Malaysia, Sumatra, and Borneo. An additional explanation might be related to the coarse sandy soils of central Sundaland. However, the short duration of these dry savanna conditions make it an unlikely sole cause for the biogeographic pattern. A dispersal barrier in the form of a dry savanna corridor during glacial maxima has been proposed to explain this disparity. With these data in hand Pan-STARRS will revolutionize our knowledge of the contents and dynamical structure of the solar system.The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass. Within its first year Pan-STARRS will have detected 20,000 Kuiper Belt Objects and by the end of its ten year operational lifetime we expect to have found 10 7 Main Belt objects and achieve ~90% observational completeness for all NEOs larger than ~300m diameter. In a single lunation Pan-STARRS will detect about five times more solar system objects than the entire currently known sample. Roughly 60% of the surveying will be suitable for discovery of new solar system objects and it will cover the ecliptic, opposition and low solar-elongation regions.
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A single aperture prototype telescopes has achieved first-light in the second half of 2006 with the full system becoming available a few years later. It will be composed of four 1.8m diameter apertures each outfitted with fast readout orthogonal transfer Giga-pixel CCD cameras. The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) at the University of Hawaii's Institute for Astronomy is a funded project to repeatedly survey the entire visible sky to faint limiting magnitudes ( mR ~ 24).
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