Seminar Review

“Wolves and wildcats: late-Quaternary mammalian response to abrupt climate change”

A review of a seminar by Prof. Danielle Schreve

Professor Danielle Schreve from Royal Holloway University recently presented a seminar at University College London. The talk addressed concepts of 'disharmonious faunas' and vertebrate response to late-Quaternary climate change, before moving on to findings from a cave in Ebbor Gorge, Somerset. Since the cave’s discovery, over 100 tonnes of material have been removed, most of which was put through a 500μm (micron) sieve. This allowed the extraction of faunal remains including: reptiles, birds and molluscs. Some of the species at this site may have existed in environments that they were less adapted to. Animal remains from this cave may provide clues into the timing of different species presence in Britain towards the end of the last Ice Age, and their reaction to abrupt changes in climate. This review will begin to discuss some of the findings so far as presented by Professor Schreve.

 

Species found in the cave included a mixture of animals that exist in Britain today, and some which now possess a very different range. This really highlights the effect of climatic and environmental changes on species distribution.  Some of the animals found in the cave included:

           (1) Species here today: water vole, wood mouse and pygmy shrew.

           (2) Present in Britain, but not in this area: mountain hare, common vole.

           (3) Extant, but not in Britain: collared lemming, steppe lemming, narrow-skulled vole.

Mountain Hare

Steppe Lemming

Pygmy Shrew

The collared lemming has already been discussed in a previous post: Brace et al (2012). This site provides a great example of how this species, and others have changed their distribution during the late-Quaternary. Prof. Schreve highlighted that the collared lemming, Norway lemming and steppe lemming now possess circumpolar, Scandinavian, and Siberian distributions, respectively. However, at Ebbor Gorge, the cave shows evidence (from raptor pellets) that all species existed at this site, in the UK, during the same time period. Similarly, there are changes in some of the larger mammals. For example, there was a turnover between the stadial  (more cold-adapted) Arctic fox to the interstadial (more warm-adapted) red fox, immediately before the end of the last Ice Age. Clearly, the Arctic fox currently lives at high-latitudes, in regions of Arctic tundra, and is not adapted to the current interglacial climate, giving a great example of just how recently fauna in the UK has changed.

Red fox (left) and Arctic fox (right)

Evidence for hominins?

Prof. Schreve suggested that in terms of humans there was currently not solid evidence of their existence at the site in the Lateglacial sediments. Still, a number of remains have shown signs of bone marrow extraction, as well as indication of burning through discolouration. This may be evidence of hominin presence at the cave site. However, the recent discovery of a struck flint artefact in older deposits indicates the presence of hominins at some point in the past, though the precise dating has not yet been confirmed.

In all, this cave provides a great record for late-Quaternary environmental change, and associated faunal turnover. Though, as of yet it is not yet clear how far back the cave goes- Professor Schreve said that:

"The site offers a unique perspective on mammalian responses to abrupt climate change at the end of the last Ice Age and we've been overwhelmed by the richness of the fossil remains. The next stages of the research will be to explore deeper into the sediments and get a firm handle on the age of the oldest finds through radiocarbon dating".

This cave provides a fantastic example of the variety and turnover of fauna within Britain during the last ice age. So far in this blog we have discussed extinctions, the role of humans and the migration of animals within Europe during previous glacial cycles. This cave has the potential to give some great insight into late-Quaternary fauna, and it will be exciting to see how it develops in the future!

Many thanks to Professor Schreve for allowing me to write up her seminar. 

Lem-ming ask you a question

A Small mammal of the Quaternary: A Review of Brace et al

During the late-Quaternary it has been commonly noted that many large animals (the megafauna) became extinct. The smaller animals are often ignored, but this is probably because many of them survived into the present day (Brace et al., 2012). One such species is the collared lemming, which still exists in arctic regions today. This is a cold-adapted animal, which thrives during glacial conditions. Though this species remains extant, and it is often assumed that small animals were not largely affected by late-Quaternary extinctions, this lemming possesses a more complex story.

Collared Lemming: Dicrostonyx torquatus

The Story

Data collected from three sites suggests that the collared lemming underwent a series of localised extinction events, followed by recolonisation of those areas after initial disappearance. Several of these extinctions occur during climatically warm episodes (Brace et al., 2012). As a cold adapted species, it makes sense that regional extirpation would occur at this time. Whilst in contrast one of these events occurs during a period of cooler temperatures (Last Glacial Maximum). This coincides with the only known reduction in Mammuthus primigenius presence across the North of Europe during this time frame (Brace et al., 2012). So, it seems that this period of climate change has had a significant enough affect as to limit the distributions of both some of the large and small animals of the late-Quaternary.

European sampling sites of the collared lemming. Pot Cave, 
Caverne Marie-Jeanne and Trou Al'Wesse.

(Brace et al., 2012 p. 20533)

Why so many extinctions?

• It may have been climate, but the lemming was still occurring at Pot Cave, which was further North (see map).
• A link between climate and ecology: with a change in temperature and rainfall, there will be a corresponding change in vegetation type. This could have caused the repeated regional demise of the collared lemming. During warmer conditions vegetation was replaced by southern communities (Prost et al., 2010). Lemmings did not survive well in these environments, and experienced significant population contractions during these intervals (Brace et al., 2012). This could explain the repeated extinction events.

• It could be a response to loss in genetic diversity. Without this diversity, a population can fail to reproduce (Brace et al., 2012). Lack of genetic variation can ultimately contribute to population collapse (Lacy, 1997), which is a possible explanation.

Lemmings have so far survived the Quaternary, and continue to live in northern regions today. Contrary to popular belief, they do not walk off cliffs (just for the record).

If the article by Brace et al (2012) is too dense, I suggest taking a look at this summary article in the Daily Mail:

HERE

 

Thanks for Reading!

BBC Article

Just a little article

I was having a browse today and found this article on BBC Earth. It gives a really nice summary of some of the animals that were alive in Britain during the ice age. It is well related to what i have been discussing in the previous weeks. Definitely worth checking out if you’re interested, some nice visuals too!

The article basically summaries some of the most fascinating animals that roamed where many of us live today during the Quaternary ice ages. Including some of the most familiar: the woolly mammoth and the woolly rhinoceros, as well as other large herbivores such as the aurochs. A few of the most common carnivores of the late-Quaternary are also discussed such as the cave lion and the scimitar-toothed cat. Take a look at the link below.

(source)

 

See the article on BBC Earth at:

http://www.bbc.co.uk/earth/story/20150722-lost-beasts-of-the-ice-age



Thanks for the read!

To be a Hippo

A Question of Hippos

During the Pleistocene (around 11,700-2.6 million years ago) multiple hippopotamus species were present in Europe. Today, as we know, their occurrence is restricted to sub-Saharan Africa (Schreve, 2009). The reason we are discussing the hippopotamus is because during the Last Interglacial the modern African hippo came as far North as Britain, and that's quite something... We will examine their presence and movement in Europe during previous interglacials, including what facilitated their spread, and why they aren’t here now. We will also discuss another hippopotamus species which is now extinct, but with emphasis on the surviving African hippo.

Today we will look at the two main forms of Hippo during the Quaternary:

       1. Hippopotamus antiquus (European Hippopotamus)

       2. Hippopotamus amphibious (alive in Africa today) 

Hippopotamus antiquus (extinct)

Hippopotamus amphibious (extant)

A British Context

Britain contains some fantastic records of Quaternary animals, including well-documented sites of Hippopotamus appearance found in British lake and river sediments (Schreve, 2009). During the Pleistocene, the British Isles were joined to the mainland (van der Geer et al, 2014). In this time Britain experienced  a single occurrence of the species Hippopotamus amphibious during the Last Interglacial (Marine Isotope Stage 5e 'MIS5e'), which represents the time period between around 128-116,000 years before present. During this interglacial mean summer temperature in the South was around 4^oC warmer than contemporary values (Schreve, 2001, Schreve 2009). Today this species possesses a low-latitude distribution surviving only on the continent of Africa. In contrast, Hippopotamus antiquus appeared between round 2-1.6 million years ago in Europe (Madurell-Malapeira, 2012). It was widespread and common until its extinction in the latter part of the Pleistocene. Hippopotamus antiquus has been recorded during multiple interglacials across most of Europe, and was a common feature during warm phases (Owen-Smith, 1992). 

Climatic importance & aids to dispersal?

Hippopotamus amphibious is of particular interest. It was only present in Britain during the Last Interglacial. This suggests that it must have undergone extensive spread throughout Europe in order to reach the British Isles as its presumed most northern point. Hippopotamus amphibious dispersal during MIS5e into Britain was likely allowed following the abrupt rise in temperatures during the onset of the Last Interglacial (Stuart, 1975). Though,  Hippopotamus amphibious from a French site is found to occur during both Marine Isotope Stages 11 and 7, but not during substage 5e. We all know that the hippopotamus is a warm adapted genus, for that reason it is questionable as to why this particular species was not around during another warm period at this site. So maybe climate was not the only factor allowing hippopotamus to spread into Britain? Animals present in Britain apparently show greater similarities with those in Germany during this timeframe, rather than the French fauna (Schreve et al, 2007; Schreve, 2009). This could mean that, yes, climate has allowed hippopotamus species to spread this far North, but it could be that the River Rhine (Germany) and the River Thames (England) facilitated the spread of the hippopotamus into Britain at this time (Schreve, 2009). The importance of this is to understand that a lot of the time no one factor can explain the spread of a species. In this case, it may be a combination of factors which allowed the first and only survival of Hippopotamus amphibious in Britain.

Extinction & Range Reduction

Hippopotamus presence in Europe is thought to have lasted into the early part of MIS3, which began around 60,000 years ago. Here, remaining populations of the genus survived in southern Italy (Pandolfi and Petronio, 2015). Although we know that Hippopotamus amphibious survives today in suitable African habitats, the story of Hippopotamus antiquus is less obvious. Though, climatic and environmental changes are considered likely the cause of their disappearance. Still, varieties of dwarf hippo (due to isolation) which possibly derived from both of these species occurred on the Mediterranean Islands, and may have survived up until as late as 8,000 years ago (Owen-Smith, 1987).

 In Summary

The importance of this post is to understand that multiple factors can lead to the spread of animals, and that the reason for their disappearance is not always well documented. In the case of hippopotamus species, the story is not entirely clear.

Soon we will be discussing some of the smaller animals of the Quaternary.