...and it all comes to an end.

The 14th & Final!

So it has all come to an end after (three?) months of blogging (it seems so much longer). Today will not only be my first post in 2017, but also a final conclusion to the blog bringing together all the elements we have been discussing in the past 13 posts (and hopefully finding some common themes)! I have enjoyed writing this blog, and have certainly learnt a lot along the way, and I hope you have too! Today we won't be introducing any new information, but rather this post will be committed to combing the previous discussions of Quaternary extinction and migration that have been covered since beginning in October.

So let’s get down to it!

What have we talked about in the past 13 posts?

Extinction Causes has been a key theme during the progression of this blog series. Below are the main explanations we have discussed, as well as the extent to which they are supported by academic literature:

The Overkill Hypothesis (Humans): Unlike in previous points in the ice ages, the late-Quaternary saw widespread extinctions. Some scientists advocate that the development of anatomically modern humans, and their hunting techniques are to blame. This hypothesis has good support.

Climate Change: Was climate change to blame? Perhaps. In the past and into the future many researchers advocate the leading role in climate change as a reason for species extinction. It has become increasingly clear that all extinct (and regionally extinct) species were effected to some extent by changes in climate. Climate change undoubtedly played a role in extinction.

The Hyperdisease Hypothesis: This was one of the first posts. In North America, there is evidence for tuberculosis among populations of mastodon. Some have taken a human-derived disease as the cause for mass extinctions. Although disease may have affected North American mastodon, there is NO evidence for this in Europe.

The Extraterrestrial Impact Hypothesis: Mineral and chemical evidence from an ‘impact layer’ is used as the cause for extinction, including the onset of the Younger Dryas. This hypothesis has many holes, and has been largely discredited. 

Hopefully you can see from this that there are two key hypotheses in this discussion: humans and climate change. 

(Source, Source)

& just how did they affect fauna?

Species- proposed total and regional (still extant) extinction causes:

Here are presented the majority of the species that have been discussed in this blog, in the context of what scientific literature (discussed in previous posts) suggests may have caused them to become extinct.

Woolly mammoth (Mammuthus primigenius): climate and people (cold adapted tundra species).

Straight-tusked elephant (Palaeoloxodon antiquus): climate and environmental change (warm adapted).

Cave Lion (Panthera spelaea): climate and environmental change, possibly associated prey loss.

Extant Arctic fox (Vulpes lagopus): climate and environmental change (cold adapted).

Extant Collared Lemming (Dicrostonyx torquatus): climate and environmental change (cold adapted).

Extant African Hippopotamus (Hippopotamus amphibious): climate and environmental change (warm adapted).

European Hippopotamus (Hippopotamus antiquus): climate and environmental change (warm adapted).

Cave Bear (Ursus spelaeus): climate and vegetation change (predominantly herbivorous).

Woolly rhinoceros (Coleodonta antiquitatis): likely climate (cold adapted), humans may have played a role.

Interglacial rhinoceros (Stephanorhinus hemitoechus): climate and environmental change (warm adapted).

The dodo (Raphus cucullatus): Humans!

Top left (cave bear: source), bottom left (arctic fox: source), top right (dodo: source), bottom right (woollyrhinoceros: source).

& so we begin to answer those initial questions...

What was here?

How, and when...

& Why isn’t it here now...?

Personally, I believe that humans were not singularly responsible for the extinction of most of the fauna that disappeared during the late-Quaternary. Though, there is plenty of evidence throughout the past that we have played a key role (see: penultimate post). I believe from the papers that I have reviewed throughout this blog series, that it has been a combination of climate-driven environmental change and (sometimes) the contribution of human activity that has caused animals to become extinct. There are many cases where regional extinction of species (e.g. collared lemming: post 6) had nothing to do with human activity, moreover it was large mammals (e.g. woolly mammoth: post 2) that faced the true consequences of early-human (or hominin) interaction. More research is necessary, and it is up to you to form your own opinion. Still, I leave you with a statement from a now aged but still very relevant paper by Anthony Stuart:

Stuart (1991) “Extinctions did not occur earlier in the Pleistocene because ‘anatomically modern humans’ [us] with upper Palaeolithic hunting technologies were not present” (p. 550)

This may very well be true.

So that’s it, the 14^th and final post. I hope that someone has found use from this, because I have certainly learnt a lot from writing it.

(Source)

Thanks for reading, and goodbye!