A new study that reconstructs the effects of past climatic changes on 59 species of North American turtles finds that the centers of the turtles’ ranges shifted an average of 45 miles for each degree of warming or cooling.
While some species were able to find widespread suitable climate, other species, many of which today are endangered, were left with only minimal habitat.
Species in temperate forests and grasslands, deserts, and lake systems, primarily in the Central and Eastern US, were more affected by climate change than species occurring along the Pacific Coast, in the mountain highlands of the Western US and Mexico, and in the tropics, according to the study published today in the journal PLOS ONE.
The study integrates data from more than 300 published studies on turtle physiology, genetics, and fossils with new models of species’ response to climate-change cycles over the last 320 millennia to draw its conclusions. During this timeframe, Earth passed through three glacial-interglacial cycles and significant variation in temperature.
“By studying how turtles responded to these climate cycles, we can learn about regional differences of the impact of climate change, how climate change differently impacts species, and how climate has influenced evolution,” said co-lead author Michelle Lawing, a postdoctoral fellow at the National Institute for Mathematical and Biological Synthesis.
Quantifying niche conservation in historical time scales is crucial to estimate future extinction risks due to climate change, explained co-lead author Dennis Rödder, curator for herpetology at the Leibniz-Institute for Terrestrial Biodiversity Research at the Zoologisches Forschungsmuseum Alexander Koenig in Bonn, Germany.
“This study, which for the first time comprehensively integrates all available information for the majority of all North American turtle species, provides profound evidence of how global warming will affect the genetic architecture of the turtles,” Rödder said.
The research suggests that the rate of climate change today is much faster than the turtles’ ability to adapt naturally and evolve to tolerate the changes. Turtles will have to continue to shift their geographic ranges to keep up with the changing climate, yet new real estate for the turtles might be running out.
“In the past, turtles have coped with climate change by shifting their geographic ranges to areas with more compatible climates. However, it is more difficult for modern turtles to do that with today’s managed waterways and agricultural and urban landscapes,” said co-author David Polly, associate professor of geological sciences at Indiana University.
More than half of the world's approximately 330 species of turtles and tortoises are threatened with extinction due to illegal trade and habitat loss, according to the Red List maintained by the International Union for Conservation of Nature. Turtles and tortoises, which evolved about 220 million years ago, are at a much higher extinction risk than many other vertebrates, paralleled only by primates, according to the IUCN. Many of the most threatened turtles and tortoises are in Asia.
Citation: Rödder D, Lawing AM, Flecks M, Ahmadzadeh F, Dambach J, Engler JO, Habel JC, Hartmann T, Hörnes D, Ihlow F, Schiedelko K, Stiels D, Polly DP. 2013. Evaluating the significance of paleophylogeographic species distribution models in reconstructing quaternary range-shifts of Nearctic Chelonians. PLOS ONE.Weitere Informationen:
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
26.09.2017 | Life Sciences
26.09.2017 | Physics and Astronomy
26.09.2017 | Information Technology