Tag Archives: biodiversity

Amphibian Pandemic

One of the unfortunate hallmarks of the human condition is our purposeful or incidental reduction of biodiversity everywhere we go. Most obvious was the elimination of large herbivores from woolly mammoths to giant ground sloths. This makes a certain sense as they were prey species which fed our rapid expansion across the planet.

Global warming, by forcing changes to the climate, impacts all life on the planet. Fauna are indirectly threatened by simple reduction of suitable habitat. The International Union for the Conservation of Nature (IUCN) has identified habitat loss as a main threat to 85% of all species described in the IUCN’s “Red List” (those species officially classified as “Threatened” and “Endangered”).

A common example is when forested areas are cleared and converted to agricultural use. The destruction of diverse forests in southeast Asia for use as palm oil plantations threatens everything from Orangutans to Tigers.

An incidental apocalypse is now occurring with amphibians worldwide. The class Amphibia has existed for over 300 million years. Today frogs, toads, salamanders, and the lesser known caecilians are dispersed worldwide and exist in a number in niches from rain forests to deserts. A northern most amphibian is the wood frog of Alaska which literally freezes up during the winter. When the weather warms it thaws and goes about its business.

Compounding threats to amphibians from habitat loss and climate change is a rapidly expanding pandemic of a Chytrid fungus, specifically Batrachorchytrium dendrobatidis (BD.) The fungus has been know for over a century in parts of east Asia and Africa but only in the past few decades has it spread worldwide.

There are several hypotheses for the mechanism of dispersion. In the 1930s a British researcher by the name of Lancelot Hogben, hence the eponymous Hogben test, found that injecting urine from a pregnant woman into the the African Clawed Frog induce the frog to lay eggs. The test was faster and didn’t require the sacrifice of the animal as was the case in the rabbit test. It was used on several continents from the 1940s to 1960s.

Recent study of the DNA of numerous samples suggests the origin of the BD dispersion began on the Korean peninsula in the early 1950’s. The Korean war, with the massive movement of men and materiel in and out of the area could have dispersed the fungus. The fungus can easily be transported on any kind of moist material, in addition to the amphibians themselves.

The global trade in amphibians for foods and pets is probably responsible for the dispersion of new strains which may be even more toxic. BD grows on the skin of amphibians. Amphibian skin is responsible for much metabolic activity such gas exchange. Essential electrolytes, Sodium and Potassium are also exchanged across the skin and it is a disruption of electrolyte balance that kills them.

Of the roughly 7000 amphibian species, 200 have recently been extirpated, and another 2000 are threatened. Nearly half of all amphibian species are in decline. Defenders of Wildlife here in the United States has called for the Fish and Wildlife service to ban the import of amphibians.

The moral of this story is that we ought to leave the critters be. Transporting them from hither to you could very well accelerate the amphibian pandemic.

Environmental Services

mangrove atoll

mangrove atoll


Environmental services is not only a name for numerous companies that provide, well, environmental services but also the concept that our environment provides many services to humanity. Also called ecosystems services, these range from the obvious such as recreation and food to the not so obvious but critical – regulation of the climate. Because of the burgeoning human population and the ever increasing use of fossil energy sources, these services are being taxed like never before.

The importance of climate stability is in the news daily for those willing to pay attention. The trend for decades has been that every year is warmer than the last, glaciers and polar ice are melting at an alarming rate and sea levels are rising (three-quarters of the world’ megacities are coastal.) Less commonly addressed are some physical changes occurring in the oceans.

The oceans provide half the people in the world with their principal source of protein. Ocean fisheries provide sixteen percent of all protein consumed by humans. These food sources are under threat and the threat can turn into collapse (of fisheries for example) frighteningly fast. This has been shown already due to overfishing.

The grand banks off the coast of Newfoundland had been the world’s premier cod fishery. Europeans may have fished the site even before European settlement, but surely by the sixteenth century. Hundred’s of millions of tons of cod were taken over the centuries, a supply thought to be inexhaustible. In the late fifties, fisheries managers began to grown concerned. In 1968 the catch had dropped to just under a million tons. Just six years later it was down to under fifty thousand tons. The Grand Banks are now closed to international fishing. In a couple of decades, the blink of an eye in terms of human populations, the world went from “inexhaustible” to gone.

Conceivably other fisheries can be managed or at least one would hope. It is also hoped that burning fossil fuels can be managed, but there is little sign of that happening here in the United States. Two factors negatively impact ocean fisheries due to burning fossil fuels, heat and acidity. Both these problems have to do with the solubility of gasses in liquids. Unlike solids which are increasingly soluble in liquids, gasses are just the opposite. Atmospheric gasses such as Nitrogen and Oxygen dissolve better in colder water.

Those who fish the streams and lakes of Arkansas know that trout can only survive in cold water. Colder water contains more Oxygen which trout require. Cool water fisheries support species such as smallmouth bass whose Oxygen requirements are less than trout but greater than largemouth bass.

The long and short of it is that as the oceans warm they loose Oxygen which can stresses fish – they are slowly suffocating.

The other ocean problem is the dissolution of Carbon Dioxide (CO2) which causes acidity. Although CO2 is a gas it reacts with seawater to become carbonic acid. The oceans are now about thirty percent more acidic than at the start of the industrial revolution when burning fossil fuels began in earnest. Coral reefs, the nurseries of the oceans are suffering from damage due to both heat and acidity.

Species Extinctions

President Obama, when announcing his clean power plan to reduce carbon emissions said “we only get one home. We only get one planet. There’s no plan B.” The current human population is about 7.4 billion and growing by about 80 million a year. The United Nations population program projects a global population of 11 billion people by the end of this century, on our only planet.

Humans and our as yet unrestrained growth are having a profound impact on our only home, planet earth. We have transformed our atmosphere by filling it with excess carbon dioxide from burning fossil fuels and deforestation. The oceans are becoming more acidic from the same carbon dioxide dissolving to form carbonic acid. Agriculture has transformed over 80 per cent of the arable land and 50 per cent of the total land surface.

Our evolutionary success comes at the expense of the rest of the planet’s wildlife. We are driving other species to extinction at an unprecedented rate. Species come and go but scientists at the World Wildlife Fund estimate that human activities have accelerated the rate by over a 1000 times the natural extinction rate.

Our largest or possibly most gentle competitors for the resources of the planet are going first. Marine mammals are particularly stressed. A twenty million year old river dolphin found only in China is now officially extinct. The Banjii, called the “goddess of the Yangtze,” succumbed to human pressures in the form of habitat loss, suffocation in fish nets and collisions with shipping.

The world’s smallest porpoise is also the world’s most endangered. The Vaquita lives in the northern end of the Gulf of California, There are likely less that 60 animals, and these continue to die mainly in fish nets, many of which are illegal. Scientists are considering a hail Mary approach to its survival similar to the successful effort to save the California Condor. The rescue plan would involve collecting and captive breeding to rebuild stocks of the Vaquita. The problem is that this animal has never been held in captivity and uncertainties abound.

All 5 of the worlds species of Rhinoceros are endangered. Fewer than 60 Javan and 100 Sumatran Rhino’s survive in southeast Pacific Islands. Other Rhinos in India and Africa are more numerous but still critically endangered.

All is not lost however, as there are a couple of uplifting trends. A giant concern for the future is global warming. On that front there is some good news. Carbon free energy sources around the globe are the fastest growing source of new power. Simultaneously at least here in the US, our per capita consumption is actually decreasing. Even though there are more of us, we each are using less.

Most promising for the planet is the strong positive correlation between increased women’s education and birthrates. The more educated a woman, the fewer children she will have. Also more educated women delay childbirth and are therefore better able to provide for the children they have.

Global Warming and Biodiversity

Global warming denial takes many forms and for a number of reasons. One factually true but disingenuous form of denial involves the claim that climate change has happened before and will happen again so we don’t need to take action.

It is factually true that the climate changes. But the changes which have occurred in the past generally took anywhere from tens of thousands to millions of years. On these time scales plants and animals adapt and net biodiversity is at least stable or even increases due to evolutionary adaptation to change.

Rapid climate change such as we are observing now is occurring at a pace which drives species to extinction. Slow climate change can be good as it leads to greater biodiversity but rapid climate change is always bad as it reduces species diversity. The richness, the real value – even economic value – of a biome is related to the diversity of organisms present.

Ecologists discuss this in terms of environmental services. Environmental services are the benefits we derive directly from our environment. Climate stabilization, biogeochemical cycles, the hydrologic cycle, soil development and protection, pollination services, and pest control are among the services provided by diverse environments.

Climate stability depends to some degree on forestation which removes carbon from the atmosphere while providing an environment that harbors much other biota leading to richness.

Biogeochemical cycles which release nutrients and build soils are enhanced by a rich biota that contribute to the process. Decomposing plant matter release substance which help build soil which contribute to more and more diverse biota.

The hydrologic cycle is stabilized to large degree by the flora and fauna. The flora provide soil stability and nutrients for herbivores. Herbivores feed carnivores. Fauna such as beaver are described as a keystone species. They enhance wetland habitat, reduce downstream flooding, and reduce silt runoff. In so doing they provide an important niche for other species as diverse as predators -wolves, coyotes, and mountain lions and any number of prey organisms like fish. The fish service the environment through fertilization for more flora.

Over a third of the human diet depends on insect pollination of vegetables, legumes, and fruit. Even meat production requires pollination of important feedstock such as alfalfa. Pollination is a service for which there is NO practical alternative.

While we are on thirds, over a third of crop production is lost to pests. Literally tens of thousands of insects exist in predator prey relationships. Invariably the more diverse the biome the more stable and therefore predictable is the environment.

Finally there are untold miscellaneous services. The majority of drugs come from or are produced synthetically but patterned after substances from nature. Woodpeckers are studied to learn how to build crash helmets, squid nerves can be a thousand times as long a human nerves and their study important to neurology. Even the study of primates, related indirectly to human ancestors, can tell us much about the evolution of human behavior.

Climate stability helps maintain a richness to our lives. Rapid climate change will if we allow it, produce a warmer, flatter, less attractive human existence. Is that what you want for future generations?