Climate impacts amphibians but isn’t main reason for decline - via Herp Digest

Wildlife Society, Dana Kolinsky October 24, 2018

The spotted salamander (Ambystoma maculatum) is one of the amphibian species that has faced declines in the eastern United States and Canada. ©Brad Glorioso/USGS

Researchers know that frogs, toads and salamanders have been facing steep declines in recent decades, but is climate change the main driver?

Putting together data from across North America, including studies of 81 amphibian species, researchers concluded that overall, it’s not.

“Climate does explain why some declines are more severe,” said David Miller, an associate professor of wildlife at Pennsylvania State University and lead author of the study published in Nature Communications. “But it doesn’t explain why amphibians as a whole are declining and whose decline is the worst.”

Miller and his colleagues, as part of a U.S. Geological Survey working group looking at climate and amphibian decline, collected amphibian research from around North America. They included 500,000 observations at more than 5,000 sites.

Then, the team collected climate data from the sites, such as water availability during breeding, summertime heat spells, humidity, snowfall and freezing data.

Using this information, they made predictions of what would happen to amphibian populations if the areas warmed. They found that changes in climate over the past 30 years do not account for amphibians’ steep declines. Changes in climate, especially in temperature, has both positively and negatively affected amphibians, they found.

So what are the reasons for these massive declines? Researchers are focusing more on deadly pathogens such as chytrid fungus and ranavirus, Miller said. But while climate may not be the primary driver, he said, his study has identified species and regions that appear to be more sensitive to climate.

“One of the areas we see this is the high altitude montane sites in the West,” he said. “Yellowstone, Glacier, Banff are all areas that our models would predict have had climate-related declines.”

Chimpanzees sniff out strangers and family members

October 23, 2018, Max Planck Society

Chemical communication is widely used in the animal kingdom to convey social information. For example, animals use olfactory cues to recognize group or family members, or to choose genetically suitable mates. In contrast to most other mammals, however, primates have traditionally been regarded as "microsmatic—having a poor sense of smell. Although research on olfaction in some primate species has increased in recent years, non-human great apes have been greatly neglected in these studies. Researchers from the University of Leipzig and the Max Planck Institute for Evolutionary Anthropology as well as Durham University have now conducted one of the first studies investigating the signaling function of social odors in non-human great apes. 

The scientists presented two groups of chimpanzees with urine from group members, strangers and an unscented control in aerated plexiglass boxes and videotaped their behavior. Chimpanzees sniffed longer at urine than at the control, suggesting they perceive the odor of other chimpanzees. More importantly, they discriminated between the smell of group members and strangers, sniffing outgroup odors longer than ingroup odors. "Chimpanzees are highly territorial, and encounters between groups are mostly hostile—in fact, they sometimes kill individuals from other communities—so olfactory cues might help them to locate other animals and determine whether they are group members or strangers, enhancing their survival and leading to fitness benefits", says lead author Stefanie Henkel of the University of Leipzig and the Max Planck Institute for Evolutionary Anthropology. "Odor might be especially important because most chimpanzees live in dense forests where visibility is low, and because in chimpanzee societies, group members split up into subgroups that may not see each other for days", Henkel adds. 

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Extinction Has Five Faces - via Herp Digest

by Whit Gibbons, Savannah River Ecology Lab, University of Georgia October 14, 2018

"Extinct" is a word first used in 1432 according to the Oxford English Dictionary. Like many commonly used words, "extinct" can be depicted in different ways, including five fairly discrete categories. 

Dinosaurs and millions of other prehistoric species can be placed in the category of pre-human extinction, the end-line of natural evolutionary processes, a condition no human can be blamed for. The second category is human-caused extinctions, such as passenger pigeons, Carolina parakeets and dodos, for which no one alive today can be held accountable.

A species that existed in our lifetime but is no longer present falls into a third category – modern extinction. Humans living today can be held responsible, some much more than others, for most modern extinctions. The causes leading to modern extinctions include such obvious ones as direct killing and unregulated pollution. But the foremost culprit and continuing threat to most wildlife is human destruction of natural habitats.

The fourth category is a term I first saw used in the Wall Street Journal – commercially extinct, which is appropriate terminology for a business-oriented newspaper. A commercially extinct species is no longer economically feasible to harvest, although the species may be present, even abundant, in some areas. Commercial extinction can be a precursor to complete elimination. The Atlantic codfish, once a staple food item in Boston, is now considered by some experts to be almost commercially extinct.

The fifth category is ecologically extinct. Unfortunately, these fourth and fifth categories are often the stages at which we begin to pay attention. Once a species becomes ecologically extinct, keeping it extant (in existence) requires biological life support. For example, the California condor was once ecologically extinct, but U.S. Fish and Wildlife Service programs demonstrated that recovery is possible. This magnificent species persisted for a while on a human-designed welfare system, with the young being raised in captivity. Some now roam free, but their fate is still as precarious as ours would be if we were clinging to a cliff ledge in the Grand Canyon where a few survive.

A fundamental measure of a species’ condition is whether it is extinct or extant. Black or white. But ecological gray zones of impending extinction should attract our notice. Is the species declining in abundance or geographic distribution? The spotted turtle is as an example of the problem. At least a couple of human generations will go by before the spotted turtle, one of the prettiest turtles in North America, will be declared a modern extinction. However, this little black turtle with bright yellow spots on the shell unquestionably has declined in numbers throughout its range. Two reasons are apparent, both related to the ecology of the species.

First, spotted turtles are popular pets, and people who like pet turtles will pay a lot of money for one. Thus, turtle collectors capture them in the wild, mostly illegally, for the pet trade. The problem: spotted turtles, even when they occur in large numbers in a wetland, can be easily collected and removed. The removal of egg-laying females can effectively eliminate a population.

The other assault on spotted turtles comes from habitat destruction. These animals, like many other wildlife species, depend on wetland habitats. The loss of small, marshy wetlands means a decrease in suitable wildlife habitat. We definitely have fewer wetlands, so who can argue that we have fewer spotted turtles now than we did even two decades ago? The spotted turtle is on a trajectory toward ecological extinction.

We should be concerned about all wildlife now, before they become commercially or ecologically extinct. Let's deal with how habitat loss and over harvesting affect their life cycles and ecology today, so we do not have to institute welfare and life-support systems tomorrow. The spotted turtle is only one example of a threatened species. Hundreds of other examples would serve as well. The word "extinct" will continue to exist, but we can limit the number of species to which the term must be applied.