Losing the Lizards: study indicates climate change can lead to global extinctions

According to a new study published last week in Science Magazine, lizards are at a high risk of extinction due to climate change. With rising temperatures, they will spend more time seeking shade and less time feeding and breeding to perpetuate the species.

Researcher Barry Sinervo of the University of Santa Cruz and his colleagues compiled data that included local population extinctions to date, climate temperature changes, and the known temperature ranges or requirements of lizard species to construct predictive models.

The research study indicates that, since 1975, local population extinctions had reached 4% worldwide and that global extinction of entire species could reach 20% by 2080 based on current rates of temperature increase.

Ever seen a lizard sunning itself? It's not actually just sunbathing or taking a snooze. As a cold-blooded "ecotherm", it is, in essence, charging its battery so that it can engage in the important activities of foraging for food and breeding. But it does so within a particular range of temperature. And since it can not sweat or pant to cool off, when it becomes too hot it heads for shade or burrows to cool down.

But when lizards are spending more time seeking cooler conditions, they are not engaged in the activities that will guarantee their long-term survival.

"So they don't die directly but they can't reproduce. It only takes a couple of generations of that and the population is going to spiral downward until it goes extinct," says Jack Sites, one of the study's collaborators and a herpetologist from Brigham Young University.

Lizards play an important role in nature's food chain, feeding on insects and being a food source for larger animals like birds. Their loss would definitely have a severe impact on local ecosystems but just how devastating that would be is hard to determine. It is something that scientists, like Sinervo, would prefer not to have to find out.

"The numbers are actually pretty scary. We've got to try to limit climate change impacts right now or we are sending a whole bunch of species into oblivion," Sinervo said.

Read the Science Magazine abstract/article.
Read MNN article about the study.

Conserving The Crocs: Columbia's proactive approach with villagers to protect threatened reptile

I was watching a re-run of the PBS program series, Nature, and there was an interesting episode on monster crocodiles. The researcher was traveling the world in search of 20-foot+ crocs, most of which having been hunted over decades either as trophies, for their hides, or in defense of cattle and, in some cases, local villagers. The net effect was that these super-size reptiles were becoming a rarity, if not all together extinct.

Then today I read an interesting follow-up on the Conservation International (CI) web site. CI has been involved in working with government officials in Columbia and members of the IUCN in getting local villagers to help conserve remaining populations of American crocodiles that inhabit Columbian wetlands and mangroves. Although illegal to catch, subsistence-level villagers are enticed to catch crocodiles and sell them on the black market.

"Within the mangrove wetlands, the crocodile is an important umbrella species which helps to sustain the functioning of the ecosystem; among other benefits, crocodiles often eat dead fish, keeping the water clean for the other species that rely on it – including humans."

With the new government-sponsored approach, by locating crocodile egg nests, retrieving the eggs, incubating and raising them in a hatchery for the first year or so, then releasing them later into the wild, the hunters-turned-conservationists are improving the odds for the survival of the crocodiles, compared to how their dwindling numbers would survive on their own. Maintaining a healthier balance in the wetland/mangrove ecosystem means allowing nature's predators and scavengers to thrive, producing a stronger and healthier population of fish and better water quality - which benefits both the ecosystem and man.

Much like what happens when sharks are protected, rather than hunted, in reef areas, local villagers benefit from a healthier ecosystem that is a food source and there is also the ancillary economic benefit derived from ecotourism - crocodile tours have sprung up in Columbia.

Once again, protecting the environment pays off in more ways than one.

Read the entire Conservation International article.

Crocodile Hunting: Australia rejects safaris to manage population

Sharks are not the only predators subject to discussions regarding their numbers and possible interactions with man. In the Northern Territory of Australia, crocodile populations have increased from a record low of 3000 in the 1970's, for both salt and fresh water species, to an estimated number today of 80,000 for just the saltwater species alone. The increase was the result of legislation that protected the crocodiles and limited any government-sanctioned culling to 600 per year.

But with that apparent ecological success story and the unfortunate deaths of four people by crocodiles, all in the month of March of this year, the Northern Territory government proposed "crocodile safaris" to allow tourists and trophy hunters to increase the number of crocodiles hunted with the idea that would correct the problem of crocodile-human interactions.

The proposal was rejected by Australia's environment minister who has, instead, increased the number of eggs that can be harvested and the number of crocodiles that can be legally culled.

Peter Garrett, environment minister, said, “I am of the view that safari hunting is not a suitable approach for the responsible management of crocodiles.” The prime minister of the Northern Territory has said that he would continue to press for the safaris.

This situation brings into question the entire issue of how does one "manage" any species to sustain its population, if management is required at all? With tourists and hunters entering the picture, one could not guarantee that the most "appropriate" animals would be taken - appropriate meaning older mature males or females who have had the opportunity to reproduce (if this is applicable to crocodiles; and I must admit I know little about them).

Another issue to consider is the circumstances behind the rash of human fatalities. Are crocodiles encroaching upon humans? Are humans, through increasing development or urbanization, encroaching upon the reptiles? Is the Northern Territory, when in a healthy environmental condition, an area where these and other types of animal interactions are to be expected? (A crocodile cruising down the main street in Miami is one thing; a croc resting near the green at the 9th hole of a golf course next to the Everglades is a different story.)

And then there's the concept, suggested by some, to let nature take its course, that the growing population of crocodiles would ultimately self-regulate based on available prey and natural selection (an increased population can also mean more sick and less "successful" crocodiles which would, over time, ultimately impact the population and balance it out in line with the overall ecosystem). The counter-argument would question how long this natural selection would take, since the current Northern Territory crocodile population has been growing steadily for over 30 years.

Sharks in the oceans, mountain lions and coyotes in the hills, even lions in the savannahs - all have populations at risk and all have the potential for human interaction. If we choose to regulate the species ourselves, we must do it with an eye on the entire health of the ecosystem in which they live and to remind ourselves who is encroaching on who.
Read entire article in Embrace Australia.

California Desert Tortoise: under the gun of the U.S. Army

The US military does not exactly have a sterling record when it comes to balancing the concerns of military training and wildlife conservation issues. The controversy over Navy sonar tests and the effects on ocean mammals is still ongoing. And we also have one brewing in California involving the endangered desert tortoise.

The Army wishes to expand its tank training operations in the Mojave desert outside of Ft. Irwin and this encroaches on the federally designated critical habitat for the desert tortoise, a reptile technically listed as threatened by the IUCN. In 2008, under the previous administration, the U.S. Fish and Wildlife Service granted permission to move 650 tortoises as part of a phase approach; the total number to be moved was to be 2000.

So far, the results have not been promising for the tortoise as many have died from predation by coyotes. Nature establishes habitat boundaries in several ways: sometimes through restricting vegetation/food sources, sometimes through geological limits - like temperature ranges, and sometimes through bio-dispersion based on predation. Move an animal out of its normal locale and anyone of these or other factors can have disastrous effects.

While the results of the first phase have not been all together successful, the Army is still pushing ahead with their plan. But they are meeting resistance from several conservation organizations, including the Center for Biological Diversity - that perennial environmental watchdog that seems unafraid to take government agencies to task in the courts.

One of the oldest residents in California is faced with what could be a fatal eviction for the sake of developing more deadly artillery. You can read more about this in the Los Angeles Times and at the Center for Biological Diversity, which is running both a public awareness campaign and a legal battle.