Humans, a keystone species?

[nibs02]

I think the subject is debatable but universally accepted, are humans considered as a keystone species?

[tianlai]

We do not consider the Earth is the center of universe just because we, the human beings having consciousness , live in Earth. I guess that bacteria are more suitable interstellar travel than Homo sapiens. Without humans the ecosystem is still full of vigor, but without microbe or green plants the ecosystem is the same as Mars. As pyramid the most important stone is in its base but not on its top.

[bbrubaker]

I'd say we're at the top of the Keystone Species list here on Earth.

[nibs02]

We do not consider the Earth is the center of universe just because we, the human beings having consciousness , live in Earth. I guess that bacteria are more suitable interstellar travel than Homo sapiens. Without humans the ecosystem is still full of vigor, but without microbe or green plants the ecosystem is the same as Mars. As pyramid the most important stone is in its base but not on its top.

Well that was really... not straight forward but okay, one person says no, the other says yes. Come on people! Are you, or not? Or are we both ways? A keystone species and an infection?

[tianlai]

I don't know why you did choose the word "infection". In my post, I just described the weighting of different ecological niches. I don't think my words including any discrimination or prejudice.

[Draco]

With out humans the Earth can still function normally. There were no humans around when the dinosaurs were the dominant species of the planet and there will be no humans around in the future but the Earth will still have roughly the same function as always.
In short, no humans are not a keystone species.

[Cat]

I think it all depends on the definition of keystone species. I read a few and they do not agree with each other. Main difference being that a) they have disproportional affect on the environment therefore, their extinction will lead to dramatic changes in the environment vs. b) their extinction will lead to extinction of other species.
According to the first definition, we are keystone species. As opposed to other species we try to control and order everything around us. Our extinction will lead to dramatic changes in the environment (probably for the better).
According to the second definition, we probably not keystone species. I cannot foresee our extinction leading to that of other species.

Does anyone know which is the "official definition"?

[canalon]

I think it all depends on the definition of keystone species. I read a few and they do not agree with each other. Main difference being that a) they have disproportional affect on the environment therefore, their extinction will lead to dramatic changes in the environment vs. b) their extinction will lead to extinction of other species.
According to the first definition, we are keystone species. As opposed to other species we try to control and order everything around us. Our extinction will lead to dramatic changes in the environment (probably for the better).
According to the second definition, we probably not keystone species. I cannot foresee our extinction leading to that of other species.

Does anyone know which is the "official definition"?

I am not enough of an ecologist to debate the definition, but I know enough to be sure that humans are a keystone species according to the 2nd definition too. I can think that many plant species, and probably a few animal one, that are used and bred for our agriculture and pleasure, would disappear quickly in the absence of man to care for them.

[Cat]

It is a possible argument, but I think you are confusing species with cultivars or breeds. Even if the Granny Smith apples die out, apple species (wild apples) would not. Same goes for animals.

[Ixiliap]

Interesting question

Well.... hmmmz... keystone species...don't think so, but arguable.

I think in general, all definitions would agree on the fact that ecosystems would change radically, AND that it would lead to species extinction.
Although the wikipedia.com has something interesting to say about it though: "A keystone species is a species that has a disproportionate effect on its environment relative to its abundance...."
Humans are pretty abundant on the face of this tiny marble we call earth, and thus, as a total population pretty effective on manipulating other species. In that respect: "No We are not a keystone species!"

In that respect I think if, for some reason, we would all instantly disappear/vaporize, ecosystems would change. Although not as quickly as would happen under the extinction of a keystone species, but change would come more gradually. This because things like constructs and farmland would take a far longer time to effectively disappear than would the human-population.

These are the things that would make us ecological engineers, like the beaver (maybe not the best comparable species), rather than a keystone species.

[Cat]

I am not sure that there are any species that would become extinct if we are gone. Ecosystem will change drastically and most likely much faster than we would like to imagine. Farmlands will be overtaken by weeds in a matter of months without human intervention. We defiantly make a disproportionate impact on environment, so it comes back again to the definition: does extinction of the keystone species have to lead to extinction of others (and how many other species)? If it does, then the real argument the way I see it is this: What will happen to human pathogens? Will they die or will they mutate and find other hosts? If they become extinct, does that make us keystone species? If they find new hosts, will that lead to extinction of any new hosts?