Wild Ideas: Baby, it’s warm outside

Last month, according to the National Oceanic and Atmospheric Administration (NOAA), was the warmest October on record globally in the 136 years records have been kept. Combined average temperature over global land and ocean surfaces averaged 1.76 degrees above the 20th-century average of 57.1 degrees (Fahrenheit). And it is in line with a trend in rising temperatures, as NOAA notes:

While we humans may be enjoying this fall’s warm weather, some of our native species, such as this Shenandoah salamander, are at risk because of rising temperatures.

“This marked the sixth consecutive month a monthly global temperature record has been broken and was also the greatest departure from the average for any month in the 1,630 months of recordkeeping…. The October temperature is currently increasing at an average rate of 0.06°C (0.11°F) per decade.”

While Virginia’s mean temperature in October didn’t vary much from its average, depending on the region, Northern Virginia is likely to have a warmer than average winter thanks to an active El Niño, according to NOAA. And while that may feel good to us Homo sapiens in the short term, it could spell disaster for many of our less-adaptable native species, which, in turn, could be bad for us in the not-too-distant future.

According to the Center for Biological Diversity, Earth is now in the midst of its sixth mass extinction of plants and animals — the sixth wave of extinctions in the past half-billion years:

“We’re currently experiencing the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago. Although extinction is a natural phenomenon, it occurs at a natural ‘background’ rate of about one to five species per year. Scientists estimate we’re now losing species at 1,000 to 10,000 times the background rate, with literally dozens going extinct every day.”

To a great extent, these losses can be laid at the doorstep of our species. Among other things, we’ve destroyed habitat, overused pesticides and herbicides, introduced nonnative invasive species, and warmed up our planet to an increasingly dangerous degree because of our addiction to fossil fuels.

Being highly adaptable as a species, so far we have largely managed to dodge the existential threats resulting from our behavior, including rising temperatures. Other species are not as adaptable and, having evolved to function within a much narrower temperature range, cannot change quickly enough to keep up with the current warming trend.

In mountainous areas, some species have been moving up in elevation to escape rising temperatures, only to become stranded on habitat islands, with nowhere to go as the planet continues to warm. Such may be the case for some salamanders in the mountainous areas of Virginia.

Before dismissing the importance of salamanders, we should consider that their biomass (weight) in the southern Appalachians could “easily outweigh” the combined biomass of mammals and birds, according to researcher Nelson G. Hairston in his 1987 book Community Ecology and Salamander Guilds. Other sources say salamanders outweigh all other invertebrates. Densities can be as high as two salamanders per square meter, adds YearOfTheSalamander.org. This makes salamanders important as both predator and prey species, serving as keystone species in the food web, which means their collapse could lead to the collapse of the entire ecosystem.

Among Virginia’s native wildlife, the endangered Shenandoah salamander (Plethodon shenandoah) may be one of the most vulnerable to climate change. According to the National Park Service, the presence of this species, like many other rare Appalachian salamander species, “is strongly influenced by elevation and aspect, presumably in relation to temperature and moisture gradients….”

According to the Virginia Department of Game and Inland Fisheries, the Shenandoah salamander is known to exist only on three mountains in Shenandoah National Park, at elevations above 3,000 feet in “deep pockets of soil within the talus on the north and northwestern faces” — in other words, the mountains’ cooler, damper sides. The Virginia Fish and Wildlife Information Service species booklet for the salamander says that, because of its “extremely limited range,” it “faces an extremely high risk of extinction,” with populations “at critically low levels.”

Indirect impacts of climate change can also affect many other species that time their biological functions, including reproduction and hibernation, to the availability of food. For example, some birds time their egg laying so that the eggs will hatch at the same time specific insects emerge in the spring, providing food for the hatchlings. If their timing is off because spring comes earlier, it could spell disaster for the birds.  

In coastal areas of Virginia, climate change could have even a greater impact on our native wildlife. According to Virginia Institute of Marine Science:

“Climate change is likely to exacerbate ongoing transformation of Chesapeake Bay into a novel ecosystem in which native habitat providers such as eelgrass and oysters have crashed, fish and shellfish that depend on them have declined, and alien species dominate. The simpler, less diverse ecosystems that result are less stable and often less valuable, hospitable, and desirable for humans as food and material resources, as well as places to live and for recreation.”

So, while I must admit I’m enjoying not having to don turtlenecks yet, I’m also hoping, finally, for good news for our species and those with which we share our planet to come out of the 2015 United Nations Climate Change Conference, unfolding in Paris as I write this. As the Center for Biological Diversity puts it, “It could be a scary future indeed, with as many as 30 to 50 percent of all species possibly heading toward extinction by mid-century.”

© 2015 Pam Owen

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