Monday, February 13, 2017

264. From seeds to grizzly bears

When most people think of the significance of climate change, they are concerned with the human consequences of melting ice, rising sea levels and changing weather patterns—sometimes resulting in prolonged droughts and severe storms. However, climate change also affects ecosystems as the slightest variation can have a domino effect on the organisms within the system.  Ecosystems that include plants, animals, microorganisms and non-living components, such as air, water, temperature and minerals, can be vulnerable to even minor disturbances.

One example, the Mountain pine beetle, only measures approximately five millimeters, but it is wreaking havoc on large Whitebark pines and the mighty Grizzly bear that rely on them.

According to the US Fish and Wildlife Service, “(The) Whitebark pine is typically found in cold, windy, high elevation or high latitude sites in western North America and as a result, many stands are geographically isolated.  It is a stress-tolerant pine and its hardiness allows it to grow where other conifer species cannot.” It is also considered “. . . a keystone species because it regulates runoff by slowing the progress of snowmelt, reduces soil erosion by initiating early succession after fires and other disturbances, and provides seeds that are a high-energy food source for some birds and mammals.”

Rising temperatures have allowed the beetle to move into higher elevations where the Whitebark pine used to thrive. Research by Evan Esch showed that “climate change was causing temperatures to rise in the cold mountain elevations where the whitebark pine grow, creating ripe conditions for the destructive beetle to spread.”

And because ecosystems can be complex, the impact on species are not always easy for scientists to predict.

In a Whitebark Pine Ecosystem Foundation (WPEF) climate change white paper, Keane et al, writes, “While there is little debate that atmospheric C02, is increasing and this increase will cause major changes in the climate, there is a great deal of uncertainty about the magnitude and rate of change.”

Grizzly bears rely on the seed because they are large, easy to eat and provide valuable calories. There is also evidence that the seeds of Whitebark pines increase the reproductive success of the bears—resulting in reproducing at a younger age with larger litters.

Thus, if we connect the dots, the small increase in temperature caused by climate change moves the tiny beetle north into the forests of Whitebark pines, whose seeds both feed and help Grizzly bears reproduce.

“While it is true that whitebark pine forest are likely to become more vulnerable under warming climates, the same is true for all ecosystems from prairie grasslands to arctic tundra,” the WPEF white paper warned.

Climate change is happening now; it is not going to wait four to eight years until we elect an educated president.  It should not be a political debate in which Republicans deny its existence to preserve corporate profits. Myron Ebell, advisor to the Trump transition team, recently said, “The environmental movement is, in my view, the greatest threat to freedom and prosperity in the modern world.” It’s a shortsighted, anti-science perspective—whose consequence may be irreversible ecological harm.  This year was the warmest year on record for the third straight year.

To make matters worse, Trump has nominated Scott Pruitt to lead the EPA. Pruitt is a climate change denier who has sued the EPA 14 times. Talk about putting the fox in charge of the hen house.

No comments:

Post a Comment