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Wild mammal biomass has declined by 85% since the rise of humans

ourworldindata.org

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Re: Wild mammal biomass has declined by 85% since the rise of humans

#12

Post by teruakohatu »

Here is the paper for which this article is based:

https://www.pnas.org/doi/10.1073/pnas.0801918105

The paper is about megafauna rather than all mammels.

This highly cited paper calculates the biomass of every class of organism, figure 1 is especially fascinating.

https://www.pnas.org/doi/10.1073/pnas.1711842115

Animals are tiny proportion of the world's biomass, with insects dominating that class, along with fish and molluscs.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#13

Post by pvaldes »

Lets take in mind that there is a problem to compare two groups when one group is much easier to measure than the other. The error interval in the mammal biomass should be much higher. The actual real values are probably not so extreme.

... I see, is just megafauna. The most competitive groups (rodents and bats) are deliberately excluded. The title is incorrect then.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#15

Post by thrown_22 »

izzydata wrote: post #3

How is there still an ecosystem?

1). There isn't one for big mammals any more. The majority of the ecosystem is locked up in plants and bacteria. For example fungi outweigh all _animals_ by roughly 6 times. Bacteria by 30 times and plants by 200 times.

2). We're the major drivers in the processes that used to limit biomass on the planet. The nitrogen cycle is dominated by humans [0] where depending on how you measure it we've done something between doubling it and increasing it by an order of magnitude. The same is true for all the other limiting cycles. By comparison the carbon cycle has been barely touched.

3). Mammals are rather big and we don't like big things trying to eat us/step on us. Mammal global mass has been decreasing since the last ice age when we figured out how to hunt mammoths to extinction and 8,000BC when we domesticated goats.

[0] https://en.wikipedia.org/wiki/Human_impact_on_the_nitrogen_c...

Re: Wild mammal biomass has declined by 85% since the rise of humans

#16

Post by baxtr »

bell-cot wrote: post #11

From a 2017 breakdown of the world's biomass, it appears that the "humans and livestock...of mammal biomass" were very carefully picked, to give the most extreme possible percentage - https://www.pnas.org/doi/10.1073/pnas.1711842115

From that paper:

We find that the kingdoms of life concentrate at different locations on the planet; plants (≈450 Gt C, the dominant kingdom) are primarily terrestrial, whereas animals (≈2 Gt C) are mainly marine, and bacteria (≈70 Gt C) and archaea (≈7 Gt C) are predominantly located in deep subsurface environments.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#19

Post by WithinReason »

teruakohatu wrote: post #12

Here is the paper for which this article is based: https://www.pnas.org/doi/10.1073/pnas.0801918105 The paper is about megafauna rather than all mammels. This highly cited paper calculates the biomass of every class of organism, figure 1 is especially fascinating. https://www.pnas.org/doi/10.1073/pnas.1711842115 Animals are tiny proportion of the world's biomass, with insects dominating that class, along with fish an…

The weight of all viruses is greater than the weight of all mammals
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