Chernobyl Area Survey Finds Lasting Problems For Wildlife

ninguna writes "The largest wildlife census of its kind conducted in Chernobyl has revealed that mammals are declining in the exclusion zone surrounding the nuclear power plant. While some stories seem to indicate nature is recovering, the actual picture isn't quite so great."

Comments

Humans & Mammals

[EEPROMS]

I cant help but think maybe the decline in some mammals could also be effected by the lack of humans not living there anymore. Many mammals are scavengers and make use of what we waste. Good examples are species like foxes, badgers, rats, raccoons, they thrive around humans.

Re:Humans & Mammals

[khallow]

This isn't a chicken-and-egg problem. Scavengers existed before humans evolved.

Given that it is wholly irrelevant to the original post, I wonder why you brought it up. Let's read the original post again:

I cant help but think maybe the decline in some mammals could also be effected by the lack of humans not living there anymore. Many mammals are scavengers and make use of what we waste. Good examples are species like foxes, badgers, rats, raccoons, they thrive around humans.

Is EEPROMS claiming that Chernobyl or prior human habitation responsible for evolving foxes, badgers, etc? No. What he is noting is that humans generate a lot of waste that opportunist scavengers (I use the term loosely since most such animals have several niches that they can inhabit), or sometimes their prey, eat. It is implied here that there is less food available for these mammals now that humans aren't around. That's a reasonable assertion to make since farmland in particular generates a lot more edible waste than wilderness (after all, you're deliberately growing food while you aren't in the latter case).

It's reasonable to me that it'd take a few decades for farmland to revert to mostly non-food producing vegetation (especially given that early colonizing plants like grasses, berry plants, etc tend to be good for herbivores and omnivores to eat as well as the residual farm crops). So we could see (IMHO would likely see) a decline in mammals just due to the reforestation of farmland.

changing two variables at once

[bcrowell]

The article leaves me feeling not very enlightened.

When the Chernobyl disaster happened, two changes were made simultaneously to the local ecosystem: (1) There was radioactive crud spread around. (2) Humans left the area.

It's fairly obvious that #2 should have a huge positive effect on many species. Having humans turn habitat into a city, and then drive around it incessantly in cars, is the worst thing that can possibly happen to any plant or animal's habitat. (Of course there might be a few exceptions, like mice and cockroaches, or plants that benefit from artificial irrigation, or certain plant species that tend to thrive in disturbed areas like road cuts.)

Effect #1, radiation, could be either positive or negative. A wide variety of data shows that low levels of radiation are beneficial to almost all living things, until you get to a certain dose at which the net effect starts to become negative. This is called radiation hormesis. Surprisingly, there is even a radiation hormesis effect on reproduction. That is, organisms like mice and fish actually produce more, healthier offspring when they're exposed to small doses of radiation. Radiation doses at Chernobyl are not uniform. You can look at contour maps that show how much radiation there is in different places. The dose is much, much higher when you're closer to the ruined plant. So roughly speaking, I'd imagine that some organisms a little farther out from the site would benefit from hormesis, while others closer in would be harmed. In any case, I would expect #1, radiation, to be a much, much weaker effect than #2, removing people.

The article makes it sound like they just tried to do surveys and evaluate biodiversity, and different people are getting different answers about whether biodiversity is up or down. Seems to me that this tells us absolutely nothing. If biodiversity has increased, it could be because effect #2 is extremely powerful, outweighing significant harm from #1. Or it could be that both #1 and #2 are positive (you get a net hormesis effect). If biodiversity is down, I'm still not sure it tells me anything. Maybe it just means that #2 is negative, for some counterintuitive reason. After all, you kick an ecosystem like crazy (by evacuating all the people), and it's not necessarily easy to tell what will happen. Maybe eliminating humans made it a better environment for predators, which made it a worse environment for prey animals. Maybe eliminating humans allowed a small number of weed species to take over instead of a larger number of ornamental and cultivated plants.