For Turtles, The Suburbs May Be Better Than Nature Reserves

Scientists at the Institute for Applied Ecology at the University of Canberra, Australia, have found a turtle that does better in a suburban habitat than it does in nature reserves. Eastern long-necked turtles (Chelodina longicollis) living in the suburbs of Canberra occupy home ranges nearly three times larger than turtles in the nature reserves. They are better able to cope with periods of drought, have higher population abundances and growth rates, and at last equivalent recruitment levels.

Eastern long-necked turtles, common across much of south eastern Australia, can be found in many freshwater habitats in the wild and in towns and cities. The researchers compared turtles that lived in the suburbs of Canberra to those in adjacent nature reserves, attaching miniature radio transmitters to the turtles in each habitat and following their weekly movements over the course of a year. Both turtle populations made long journeys of up to two and a half kilometres between bodies of water. It was expected that given their extensive movements, the suburban turtles would have a high rate of encounters with vehicles on roads, and thus fewer would survive. In fact, suburban turtles did not suffer appreciably higher mortality than their counterparts on reserve lands, only one of the 36 radio tracked turtles being hit by a vehicle. Vegetated drainage lines and drainage culverts running under roads protected the turtles.

Given the severe droughts that have been affecting much of Australia, the different populations’ response to drought was also notable. Turtles in the nature reserves responded to the drying up of the wetlands by lying dormant buried under leaf litter. However, suburban turtles were able to maintain aquatic activities throughout periods of drought as suburban water bodies remained flooded. Suburban landscapes, despite their unique challenges, may therefore be higher quality habitats than nature reserves for turtles during drought. The researchers hope to further evaluate whether well-designed urban areas hold any promise as long term drought refuges for some turtle populations.

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