Volume 29 Issue 3, Summer 2024

Review by Steve Allen

Grizzly bears in Alaska have two favorite foods: salmon and elderberries.

For many generations, the bears began their seasonal feast with salmon, and then, when the salmon’s spawning run ended, they would move inland to consume elderberries. Hungry bears never had to choose between the two delicacies because the elderberries ripened only after the salmon supply dried up.

Climate change has changed everything and altered this traditional and important sequence. The salmon have stayed on the same schedule, but warming temperatures have accelerated the timing of the berries by a couple of weeks. Now the two coincide, forcing the bears to choose between both tasty treats. They opt for the elderberries, which are critical to building up the stores of carbohydrates necessary for surviving hibernation during the long winter to come. This may be good news for the salmon, but it upsets the status quo for other species — like the scavengers that fed off the salmon carcasses left behind by the bears, and the microbes that break down the remains, adding nitrogen and other elements to the soil.

Hurricane Lizards and Plastic Squid by conservation biologist Thor Hansen shares this and other stories of the biology of climate change — that is, how various species react to changes in the climate that take their traditional habitat out of their comfort zone. Simply stated, when that happens, species have three options: adapt, evolve, or go extinct.

The key to adaptation is plasticity— the ability to alter one’s lifestyle when circumstances require it. That is what the bears are doing when they forgo protein-rich salmon to feed on the more crucial carbohydrate-rich elderberries. Similarly, many bird species move to higher elevations when temperatures increase too much at the lower elevations they have traditionally occupied.

The “Plastic Squid” of the title are exhibiting a more extreme form of plasticity. After a substantial increase in water temperature, fishermen thought the Humboldt Squid was disappearing from the fishing grounds of the Gulf of California. When marine biologists did a study, they discovered that the squid were abundant but were becoming much smaller, maturing and reproducing in half the time, and had changed their diet to smaller prey instead of the larger bait used by the fishermen.

We think of evolution as a long, slow process, but climate change has forced some species to evolve through natural selection in real time. Anole lizards, a Caribbean species related to chameleons, survive hurricanes by clinging to a shrub with their front feet while their bodies sail horizontally behind them. (Watch a YouTube video showing a demonstration with a leaf blower.)

After several major hurricanes decimated some small islands in the Turks and Caicos, scientists who had been studying the lizards before the storms surveyed the surviving lizards and discovered that the survivors all had larger toe pads, longer front legs, and shorter back legs than the average lizard before the storms. Not enough time has passed to determine whether these adaptations will stick genetically, or whether future generations will regress to the previous “normal,” but this may well be an example of natural selection operating in response to increased hurricane activity.

Hurricane Lizards and Plastic Squid is an entertaining, well-written, thought-provoking exploration of how climate change affects every species on the planet.

The post Book Review: Hurricane Lizards and Plastic Squid by Thor Hansen appeared first on Loudoun Wildlife Conservancy.