stumpytheorca:

—-   Hatchings on their way to the ocean (Image credit: Flickr user Jeroen Looye)

Wet beaches drown sea turtles
Climate changes may be wreaking havoc on the beaches where leatherback sea turtles nest. As sea levels rise and rain pounds on the sand, sea turtle nests get soggy. This could spell trouble for the charismatic reptile, which at six feet long, is the largest living turtle.

Under field and lab conditions, the scientists counted the number of live hatchlings that emerged. They then unearthed the nests to count the embryos that never hatched. Together, these numbers provided an overall survival rate for each incubation condition. A clear trend emerged: the wetter the sand, the lower the survival rate. On the wettest parts of the beach, no hatchlings survived at all.

These results, which will be published in the December issue of the Journal of Experimental Marine Biology and Ecology, are not entirely surprising to scientists. According to Richard Reina, a marine biologist at Monash University in Melbourne, Australia, the connection between climate change and lower hatchling survival rate was a “fairly easy inference to draw,” given previous knowledge of climate change’s effects on beach moisture.

The race between the tortoise and climate change

davidbodenham:

File:Desert tortoise.jpg

There is absolutely no denying that our planet’s climate is changing. Incontrovertible evidence manifests itself from the fields of archaeology, dendrochronology, climatology, oceanography, epidemiology, bacteriology and hydrology; to name but a few. It therefore comes at no surprise that climate change has dramatic and unforgiving effects on a huge array of organisms and the ecosystems which they occupy. Again the evidence mounts, and these unprecedented changes to our climate directly impacts on the distribution, physiology, phenology, reproduction and ultimately the survival of species around the world. The causes of climate change are still debated, but there is one undeniable fact that appears from this daunting issue. Climate change poses a serious threat to the conservation of Earth’s biodiversity.

There is a vast amount of literature concerning the impact of climate change on organisms. Unfortunately all paint the same grim picture. Much of this research concerns the demographic changes in populations of short-lived species. Through no fault of their own, researchers have focused on these species, due to limitations in time, labour, funding and logistics. However, trawling through online journals, a piece of research caught my eye. Focusing on the threatened Agassiz’s tortoise (Gopherus agassizii) , this research, spanning over 30 years, focuses of the survival and demography of a long-lived species, in the wake of the increasingly unpredictable climate of the Sonoran Desert.

image

A map showing not only the Agassiz’s tortoise range, but the recently separated species; the Sonoran Desert Tortoise. Once though to be subspecies, genetic evidence shows us that they are actually two distinct species, isolated by the Colorado river. Find out more.

Models have predicted that the open expanses of the Sonoran Desert would, as the years progressed, become increasingly unsuitable, if the climate were to become warmer and dryer. The fact is that the climate has become warmer and dryer, but has this had the predicted and unfortunate effect on the Agassiz’s tortoise population? Well the results paint a slightly more complicated picture. From 1978-1996, tortoise numbers appeared to remain constant, even though the climate did become steadily warmer and dryer. However, from 1997 onwards, persistent droughts dramatically lowered the tortoises’ survival. Dehydration and starvation appear to have been the primary cause, but predation may have also increased, as a lack of preferred small mammalian prey (a direct result of drought), has forced coyote (Canis latrans) to switch to tortoises.

The impact of climate change on species and ecosystems around the world is unprecedented, and this study, like so many others is at worst, disturbing, yet at best, revealing. On an individual level, these data provide us with evidence that the Agassiz’s tortoise population is at a real risk of disappearing. At a broader level it provides scientists with another string to their bow, when persuading others that our modern lifestyles will have a direct impact on our planet, and ultimately us.

References 

Lovich, J.E. et al. 2014. Climatic variation and tortoise survival: Has a desert species met its match? Biological Conservation, 169:214-224.

This ‘Terrapin Carolina’ (aka Eastern Box Turtle) is giving humans a sad side eye. This after it read a recent study indicating that it is one of 59 species of american turtles whose habitats are being threatened by climate change. 

(Source: phys.org)

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.

Read more at: http://phys.org/news/2013-10-climate-threatens-northern-american-turtle.html#jCp

This ‘Terrapin Carolina’ (aka Eastern Box Turtle) is giving humans a sad side eye. This after it read a recent study indicating that it is one of 59 species of american turtles whose habitats are being threatened by climate change. 

(Source: phys.org)

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.

Read more at: http://phys.org/news/2013-10-climate-threatens-northern-american-turtle.html#jCp

Turtles and Tortoises at risk due to Climate Change

“It’s not only the Aldabra which is at risk,” said David Rowat from the Seychelles marine conservation society, which heads up a programme to tag and monitor critically endangered Hawksbill sea turtles on Mahe Island’s beaches.

“Hawksbills have always been hunted for their shell to make tortoiseshell jewellery. Their numbers are low but we have the fifth largest population in the world here, and it’s imperative we act to protect them,” he said.

Changes in temperature play havoc with breeding patterns because the Hawksbills, which live in tropical coral reefs and have prominent hooked beaks, tend to produce only females if the eggs are left in a very warm nest, he said.

“The warming also means there are violent and more frequent storms. The turtles lay their eggs in the sand, but if you have a bad storm surge, you can lose big tracts of sand and a whole season of nesting turtles,” Rowat said.

“We move the nests we come across to above the high water line on the beach, but even doing that cannot always protect them from a flash surge,” he added.

A significant part of the new funds will go to projects aiming to protect and restore the coral reefs and shore up the coastline against storms.

“The ideas we’re testing include using wooden poles as a barrier to protect the coast and replanting trees to help prevent erosion, as well as attempting to regrow coral or transplant and grow more resilient coral,” Payet said.

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