Elephants. Lions. Hyenas. Rhinos. Hippos. Hunting Dogs. These animals conjure up images of a vast savannah, a wild African landscape that appears untouched by humans. But at one time, these creatures weren’t confined only to Africa: Europe also used to be a land rich in megafauna.
Ever since learning about the existence of extinct large European mammals, I have been fascinated about their history, visualising what it would be like to go back in time to experience our continent, unrecognisable. With the absence of humans, modern day Europe would be a very different place. A rich ecosystem filled with species inhabiting every possible niche, roaming across a land with few boundaries, the complexities and dramas of life and death unfolding through a cycle of seasons.
The Pleistocene was an epoch commencing around 2.6 million years ago that lasted until 10,000 years ago. This period was characterised by frequent climate oscillations, with many dramatic glacial (colder) and interglacial (warmer) events and less severe stadials and interstadials occurring. Described by palaeontologist Björn Kurtén as ‘a faunal revolution’, the Pleistocene was an era with a continuously changing animal composition: species shifted in their distributions, evolved and became extinct.
Scientists have stated that, due to the actions of humans, the earth is currently experiencing its sixth mass extinction. However, these extinctions occurred long before the present day. Significant disruption to Pleistocene ecosystems occurred when Homo sapiens arrived in Europe, with rapid losses of large animals taking place from 50,000 to 7,000 years ago. A similar chain of events occurred when H. sapiens expanded to the other continents, with an estimated one billion individual animals lost across the globe. Herbivores were hunted for food, with some tribes specialising in hunting particular species, such as horses or mammoths. Carnivores were a source of competition for resources and danger.
The climatic change that coincided with modern human arrivals placed further stresses on megafaunal populations, reducing their ability to cope with an intelligent and territorial species that can occupy so many niches. These losses also caused trophic cascades, negatively affecting ecosystem function and biodiversity.
Remains of past creatures in Britain have been found at locations including Dogger Bank in the North sea, the Crags in East Anglia and the Joint Mitnor Cave in South Devon, which contains deposits of elephant, hippo, bison and hyena bones from 125,000 years ago. Even excavations under Trafalgar Square in London have yielded hippo and elephant remains.
During periods of climatic change, species adapted and shifted in distribution: glacial refuges for species adapted to a temperate climate were Spain, Italy and Turkey. Interglacial fauna that included deer, rhinos and straight-tusked elephants were replaced by their glacial counterparts of reindeer, woolly rhinos and woolly mammoths. Interglacials were approximately 13,000 years in length, with glacials lasting much longer. The most recent interglacial before the current one we are living in was the Eemian, commencing 135,000 years ago and lasting until 110,000 years ago, when the Earth was 3-5°C warmer than today (interestingly, CO2 levels in the atmosphere were around 280 parts per million during the Eemian).
Throughout interglacial periods, the communities of large European Pleistocene mammals inhabiting a range of habitats comprised of…
- Hunting dogs
- Scimitar cats
- Giant cheetahs
- Wild ass
- Wild hogs
Learning about the communities of species that lived across Europe can give an insight into the habitats they helped to engineer. Ecologists are studying the role of extinct megafauna in the functioning of ecosystems: this is called paleoecology. As a graduate in Land Management for Conservation, I find it fascinating to study the origins of the species alive today and to discover the past influences on their evolution and ecology.
During the Pleistocene, almost all (>98%) botanical species present today were in existence and many butterflies and other insect species were too. The avifauna of present day Britain and northwest Europe is almost unchanged from previous Pleistocene interglacials. Evidence has been found of species such as swallows, skylarks, starlings, kestrels, ravens, blackbirds, long eared owls, nuthatches, blackcaps and wrens. We know the ecology of these species; therefore we have more clues when piecing together the character and appearance of past ecosystems.
Biodiversity is highest where a mosaic of habitats exists. Some species utilise a range of habitats during different life stages, others are reliant on a single habitat type for their specialist needs. At a landscape scale, a whole host of elements contribute to creating a functional ecosystem. A complete interglacial Pleistocene ecosystem contained a suite of animals, each with a role to play in helping to create a mosaic of forests, scrub, wetlands and grasslands.
Straight-tusked elephants would coppice trees, creating sunny glades for woodland flowers and butterflies. Rhinos and deer browsed scrub, encouraging dense, bushy growth suitable for bird nesting. Herds of horses and aurochs grazed grasslands, creating open spaces for wildflowers to thrive, with bees and butterflies feeding on nectar and small mammals foraging on the ground.
Hippos wallowed in lakes and swamps, whilst swallows and dragonflies hawked overhead for small insects, in turn pursued by birds of prey. As well as lions and leopards, dung beetles flourished with the abundance of large herbivorous mammals. Lions of the Cromerian interglacial (600,000 years ago) were possibly the largest felines that ever existed.
Only recently have ecologists started to uncover the effects on ecosystem function caused by megafaunal extinctions. Present day conservationists realise the necessity of large herbivores as important tools for managing nature reserves. The Oostvaardersplassen in the Netherlands is a large-scale conservation project that has taken elements of megafaunal communities to recreate a semi-functional ecosystem to benefit many species, especially birds. Konik horses, Heck cattle and Red deer are the principal grazers and browsers.
Knepp Estate in West Sussex has transformed unproductive arable land into an innovative rewilding project. Cattle, horses, deer and pigs roam freely creating a range of habitats, whilst the estate profits from tourism and selling their free-range meat. Alladale Estate in the Scottish highlands has ambitions to release top predators such a bears, lynx and wolves into a large, enclosed expanse of land.
Reintroducing extinct species is a key part of rewilding: a conservation concept that aims to restore ecological function to landscapes.
Whilst we can never fully reconstruct the ecosystems from the past, complete with all the extinct flora and fauna, we can utilise elements similar to them to create rich and biodiverse habitats for the benefit of wildlife and people. Simultaneously, we must also strive to protect the habitats and lives of the amazing megafauna that we are lucky enough to share the Earth with.
References – this post required research from a variety of sources, the following references contain a wealth of information on the topics covered.
- Kurtén, B. (2007) Pleistocene Mammals of Europe
- Large mammals were the architects in prehistoric ecosystems: http://phys.org/news/2014-03-large-mammals-architects-prehistoric-ecosystems.html
- Pires et al. (2015) Pleistocene megafaunal interaction networks became more vulnerable after human arrival. Proc. R. Soc. B.
- Malhi et al. (2015) Megafauna and ecosystem function from the Pleistocene to the Anthropocene. PNAS
- Monbiot, G. (2013) Feral: Rewilding the land, sea and human life
- Kehr, J. (2011) The Inconvenient Skeptic: the Comprehensive Guide to the Earth’s Climate
- Prins, H. (1998) Grazing and Conservation Management (Origins and development of grassland communities in Northwestern Europe).
- Images of extinct megafauna: http://www.prehistoric-fauna.com
- Rewilding Britain: http://www.rewildingbritain.org.uk