Britannica.com: Encyclopedia article on megafauna 2 Very large mammals (Mammalia) and birds (Aves), i.e. those weighing more than 50 kg. Many controversies concern the extinction of many members of the megafauna in the early Holocene, particularly in Europe and North America. Climate change is a possible factor, but most of the species involved had already survived earlier interglacial periods. The characteristic aspect of the current interglacial is the rise of man, and many megafaunal species disappeared at a time when hunting pressures were intensifying. Africa has extensive protected savannahs and these magnificent animals are mainly found in these protected areas. But even there, they must be carefully protected from poachers. It may not be a coincidence that the latest marked mass extinction of megafauna in Africa is correlated with the advent of stone tools used for felling by Homo erectus about 1.4 million years ago [6]. Megafauna or Megabenthos represent the largest body size class of organisms associated with the seabed. It includes microbial mats, “huge” single-celled eukaryotes, the largest demersal fish, and a very wide range of metazoan invertebrate taxa.
These organisms can live in the seabed, on its surface or in the water column immediately above. Populations and biodiversity of megafauna are primarily controlled by a combination of food availability and habitat temperature. The group typically characterizes fragile marine ecosystems threatened by bottom fishing and other human activities, which can be a key target in environmental management and conservation programs. This extinction event differs from previous megafaunal extinctions in that new species have failed to replace lost species. Bugwise brings the world of invertebrates to your students and engages them in real science in local environments. Find out which insects and spiders you share your garden with and why they are crucial for a healthy planet. Rapid climate change during the transition from the Pleistocene to the Holocene caused large changes in temperatures and vegetation types that had profound negative effects on wildlife, especially on larger animals (megafauna) such as mammoths, camels, horses, glyptodons and saber-toothed cats, until they eventually disappeared (Graham, 2001). Interestingly, Africa, considered the cradle of humanity, has a more diverse megafauna than any other continent on Earth. Although it has much less variety and number than before. Many theorize that the reason megafauna exists (mainly in Africa) is that humans evolved with them.
While some sources indicate that terrestrial megafauna began to disappear about 125,000 years ago, a significant and relentless reduction began towards the end of the Pleistocene about 50,000 years ago. The large-scale extinction of megafauna has generally coincided with the arrival of modern humans in different parts of the world, such as Australia or Tasmania. One of these major extinction events occurred in the Americas during the Pleistocene-Holocene transition about 10,000 years ago. Several causes have been suggested to explain such a rapid extinction: The undeniable evidence of the man-made extinction of megafauna at the end of the Pleistocene, the so-called “smoking gun” (or perhaps “blood-dripping spear” would be a better metaphor), will probably never be found. There are several reasons for this. (1) Faunal and archaeological evidence is fragmentary. We will never have a complete picture of what happened. This will always leave room for discussion. (2) The dating of events will never be accurate. Radiometric dating is the only way to date most paleontological or archaeological sites, and all radiometric data are uncertain. In this sense, they are not true ages, as could be obtained by counting annually stratified sediments or tree rings. They remain estimates of age, more or less decades to centuries if they are tens of thousands of years before the present.
(3) The first peoples of all inhabited continents were hunter-gatherers, mostly nomadic. They left pitifully few testimonies of their occupation; This remains in situ after tens of thousands of years of decomposition, erosion, post-treatment of sediments, etc. will always be only a tiny fraction of the original material, whether fossil bones or human artifacts. Further inland, you can spot all kinds of megafauna just hours from Montreal. Many archaeologists believe that human migration south to South America took place, again coinciding with the mass extinction of megafauna at the end of the Pleistocene [12]. But other analyses of the climate impact of this period on vegetation and the human impact on megafauna are inconclusive, suggesting that these factors together caused the extinction [13]. Continued human hunting and environmental disturbance have led to further extinctions of megafauna in the recent past, creating a serious threat of extinction in the near future (see examples below). Direct death by humans, especially for meat, is the most important factor in the current decline of megafauna. [72][73] At the end of the last ice age, Australia`s climate changed from cold-dry to hot-dry. As a result, surface water has become scarce. Most inland lakes have become completely dry or dry during warmer seasons.
