Wednesday, February 21, 2018

1965 & Counting



Redundancy, interconnectedness and feedback loops are just some of the reasons why biodiversity is key to life on earth, something that's beginning to unravel thanks to habitat loss, resource depletion, environmental degradation and GW, the "grand" quartet leading man into the anthropocene, the era that's rapidly moving us toward the 6th great dying if we stay the course no matter what the cost may be.

Human expansion, destruction of natural habitats, pollution, and climate change have all led to biodiversity levels that are considered below the “safe” threshold for global ecosystems. And the consequences of biodiversity loss aren’t just about the extinction of certain charismatic species.

A new study published in the journal Proceedings of the National Academy of Sciences shows that less biodiversity in an area increases the risk of a domino effect of extinctions, where one species’ disappearance can cause other species to follow suit.

The research, conducted by ecologists at the University of Exeter, shows that losing a species in an area is dangerous in that it makes the surrounding ecological community simpler, and therefore less robust to change.

It makes sense: the fewer species that exist in an area, the fewer that are available to “fill the gap” left by other extinctions. Other species in the ecosystem will have fewer alternatives to turn to. For example, if there are fewer insects left overall across a region, the bats and amphibians that eat them will feel the loss of just one species much more severely.

As an aside, 1965 marks the beginning of the Anthropocene. To whit ...

Anthropogenic activity is now recognised as having profoundly and permanently altered the Earth system, suggesting we have entered a human-dominated geological epoch, the ‘Anthropocene’. To formally define the onset of the Anthropocene, a synchronous global signature within geological-forming materials is required. Here we report a series of precisely-dated tree-ring records from Campbell Island (Southern Ocean) that capture peak atmospheric radiocarbon (14C) resulting from Northern Hemisphere-dominated thermonuclear bomb tests during the 1950s and 1960s. The only alien tree on the island, a Sitka spruce (Picea sitchensis), allows us to seasonally-resolve Southern Hemisphere atmospheric 14C, demonstrating the ‘bomb peak’ in this remote and pristine location occurred in the last-quarter of 1965 (October-December), coincident with the broader changes associated with the post-World War II ‘Great Acceleration’ in industrial capacity and consumption. Our findings provide a precisely-resolved potential Global Stratotype Section and Point (GSSP) or ‘golden spike’, marking the onset of the Anthropocene Epoch.


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