Issue link: https://read.dmtmag.com/i/75042
hree of the world's tiger subspecies now are extinct, and the Sumatran tiger is nearing extinction as humans alter its habitat. With a wild population lower than the occupancy of the average downtown high- rise hotel, Sumatran tigers are a severely threatened spe- cies. A new study that combines existing GIS datasets with land-use and habitat information gathered on the ground has determined where tigers live and the condi- tions that could save them. The study, conducted by Virginia Tech (www.vt.edu) and World Wildlife Fund (WWF; www.worldwildlife.org), is the first to systematically investigate the use of differ- ent land-cover types for tiger habitat—not just forests but also commercial plantation areas. Researchers used their data to develop a series of maps that predict where tigers are most likely to live. The study focuses on the central Riau Province in the Indonesian island of Sumatra, which has historically been seen as the stronghold for Sumatran tiger conservation. Published in the Public Library of Science's online journal, PLoS ONE, on Jan. 23, 2012 (www.plo- sone.org/article/info%3Adoi%2F10.1371%2Fjournal. pone.0030859), the study was led by Sunarto (in Indonesia, people only have one name), who earned his doctorate in wildlife science from Virginia Tech in 2011. The study received support from the Indonesian Ministry of Forestry (www.dephut.go.id/ index.php?q=en). Surprisingly, the authors found that although Sumatran tigers strongly prefer forests and tend to avoid any developed areas, the tigers could use commercial agricultural and forestry plantations that meet two key qualifications: dense ground cover and extremely low levels of human activity. Because plantations cover an increasing percentage of the landscape, knowing what makes them acceptable tiger habitat is crucial. Habitat Taken, Habitat Found? As in much of the world, economic development is the root of habitat loss in Sumatra. To meet global demand for acacia and oil-palm products, companies are clearing tiger habitat to increase the acreage of these tree plantations, reducing overall habitat lands and fragmenting what little habitat area remains. In the last 25 years, more than half of Sumatra's natural forests—an area greater in size than the state of Virginia—have been lost as they're converted to commercial plantations. Fragmentation of the natural A map shows the grids used in the study area for surveying Sumatra's tigers. JUL Y 2O12 / WWW . GEOPLA CE . COM 15 Camera traps are one of many methods used to collect data on Sumatran tigers. forest habitat creates patches too small for tigers to use and isolates local populations, causing inbreeding and increasing the population's vulnerability to local extirpa- tion (extinction within a limited geographic area). A hopeful find, however, is the tiger's strong predi- lection for sites with understory cover—thick vegeta- tion at the ground level—regardless of whether the