Great Barrier Reef: rising temperatures turning green sea turtles female

‘Complete feminisation’ of northern population is possible in near future, researchers find

Helen Davidson

Mon 8 Jan ‘18 17.00 GMTLast modified on Mon 8 Jan ‘18 22.00 GMT

Rising temperatures are turning almost all green sea turtles in a Great Barrier Reef population female, new research has found.

The scientific paper warned the skewed ratio could threaten the population’s future.

Sea turtles are among species with temperature dependent sex-determination and the proportion of female hatchlings increases when nests are in warmer sands.

Tuesday’s paper, from the National Oceanic and Atmospheric Administration, California State University and Worldwide Fund for Nature Australia, is published in Current Biology. It examined two genetically distinct populations of turtles on the reef, finding the northern group of about 200,000 animals was overwhelmingly female.

While the southern population was 65%-69% female, females in the northern group accounted for 99.1% of juveniles, 99.8% of subadults and 86.8% of adults.

“Combining our results with temperature data show that the northern GBR green turtle rookeries have been producing primarily females for more than two decades and that the complete feminisation of this population is possible in the near future,” the paper said.

The temperature at which the turtles will produce male or female hatchlings is heritable, the paper said, but tipped to produce 100% male or 100% female hatchlings within a range of just a few degrees.

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Northern Moths May Fare Better Under Climate Warming Than Expected

Sep. 24, 2013 — Moths in northern Finland are less susceptible to rising temperatures than expected, suggesting high latitude moth populations around the world may be partly buffered from the effects of rapid climate warming, according to a new Dartmouth-Finnish study based on the most extensive analyses yet conducted of seasonal patterns in forest animals.

The results are important because moths are a key food source for birds, bats and many other predators, and (in their caterpillar stage) are one of the planet's most abundant plant-eating animals and most voracious agricultural pests. The findings also underscore the value of long term ecological monitoring.

The results appear Sept. 24 in the journal Global Change Biology. A PDF of the study is available on request. The study was conducted by researchers at the University of Eastern Finland, Finnish Environment institute, Kainuu ELY Centre and Dartmouth.

Climate change is influencing natural systems worldwide by altering the annual timing of biological events among many plants, animals and insects, especially toward the poles where temperatures are increasing more rapidly and ecological effects from planetary warming are most pronounced.

The Finnish and Dartmouth researchers analyzed sensitivity to temperature of multiple populations of 334 moth species distributed over 600 miles of latitude from southern to northern Finland (about the same latitude as southern to northern Alaska). Their results show that temperature is the dominant control on most moth life cycles but that some species are more strongly controlled by day length, while others are controlled by a combination of temperature and day length. They found that climate dramatically affects when caterpillars are feeding and adults are flying, with the majority of species flying up to a month earlier in warm summers than cool summers. This is especially significant in regions where the summer lasts only a few months.

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