stables. In parallel, human activities on foot have decreased heavily over the last few
centuries and have been replaced by driving, shipping and flying.
Three periods in the extinction of biota can be linked with human history and
behaviour (Table 1; see references there).
The first extinction period occurred between 132,000 and 8000 years BP. During
the late Pleistocene and early Holocene c. 200 species belonging to 100 genera of
predominantly large mammals (>40–50 kg) became extinct on all continents except
Antarctica. In many cases, this happened long before, and outside of, regions where
agriculture occurred. Climate change and overkill by hunters or a combination of
climate change and hunting have been discussed as the main factors involved.
However, there is no evidence that climate change alone might have been responsible. Human arrival at landmasses and migration, appear to be the most important
causes of these extinctions on continents (Louys et al. 2007; Burney and Flannery
2005; Martin and Klein 1989). The transportation and introduction of pathogens
might also have affected the extinction of large mammals (Lee 1997). Sandom et al.
(2014, page 1) showed “that the severity of extinction is strongly tied to hominin
palaeobiogeography, with at most a weak, Eurasia-specific link to climate change.”
The second period began c. 1500 AD and was a result of shipping across the
oceans and the exploration of islands and archipelagos worldwide. One of the main
factors was the introduction of predators, omnivores, herbivores, plants and pathogens such as rats, pigs, goats, dogs, cats, crops, ornamental plants, bacteria and
others which were able to simply devour whole populations, and in combination to
totally change the structures of landscapes.
The third period began as international and intercontinental trade and traffic in the
twentieth century exploded (Federico and Tena-Junguito 2016). The main reasons
for species extinctions according to the IUCN Red List (iucnredlist.org, downloaded
fifth Oct. 2018) are habitat destruction, agriculture, aquaculture, biological resource
use, and invasive or other problematic species including dispersal of viruses, bacteria
and fungi. Diverse groups of plants and animals, including invertebrates, became
extinct after the Second World War, some also earlier. Amphibians have been
declining dramatically since c. 1980 due to human dispersal of pathogens and
diseases such as chytridiomycosis.
The effects of these periods were dramatic, not only for species compositions and
the existence of certain species but also for ecosystem properties. For example, the
whole biomass of wild land mammals before the Quaternary Megafauna Extinction
(c. 0.02 Gt C) is estimated as sevenfold higher than it is today (0.003 Gt C). The
global biomass of humans and livestock (0.16) by far surpasses a recent estimate of
the biomass of wild land and sea mammals of c. 0.007 GT C (Bar-On et al. 2018).
The timeline (Table 1) shows the increasing influence and pressure of humans on
nature, the increasing use of space, and increasing intensity of use. It does not show a
declining dependence of humans on their physical environment since basic requirements have not changed.
We do not have appropriate information about the psychological relationship
between humans and nature in prehistory. The idea that humans once lived in
harmony with nature is a hypothesis without any empirical foundation.
Environmental History
9
centuries and have been replaced by driving, shipping and flying.
Three periods in the extinction of biota can be linked with human history and
behaviour (Table 1; see references there).
The first extinction period occurred between 132,000 and 8000 years BP. During
the late Pleistocene and early Holocene c. 200 species belonging to 100 genera of
predominantly large mammals (>40–50 kg) became extinct on all continents except
Antarctica. In many cases, this happened long before, and outside of, regions where
agriculture occurred. Climate change and overkill by hunters or a combination of
climate change and hunting have been discussed as the main factors involved.
However, there is no evidence that climate change alone might have been responsible. Human arrival at landmasses and migration, appear to be the most important
causes of these extinctions on continents (Louys et al. 2007; Burney and Flannery
2005; Martin and Klein 1989). The transportation and introduction of pathogens
might also have affected the extinction of large mammals (Lee 1997). Sandom et al.
(2014, page 1) showed “that the severity of extinction is strongly tied to hominin
palaeobiogeography, with at most a weak, Eurasia-specific link to climate change.”
The second period began c. 1500 AD and was a result of shipping across the
oceans and the exploration of islands and archipelagos worldwide. One of the main
factors was the introduction of predators, omnivores, herbivores, plants and pathogens such as rats, pigs, goats, dogs, cats, crops, ornamental plants, bacteria and
others which were able to simply devour whole populations, and in combination to
totally change the structures of landscapes.
The third period began as international and intercontinental trade and traffic in the
twentieth century exploded (Federico and Tena-Junguito 2016). The main reasons
for species extinctions according to the IUCN Red List (iucnredlist.org, downloaded
fifth Oct. 2018) are habitat destruction, agriculture, aquaculture, biological resource
use, and invasive or other problematic species including dispersal of viruses, bacteria
and fungi. Diverse groups of plants and animals, including invertebrates, became
extinct after the Second World War, some also earlier. Amphibians have been
declining dramatically since c. 1980 due to human dispersal of pathogens and
diseases such as chytridiomycosis.
The effects of these periods were dramatic, not only for species compositions and
the existence of certain species but also for ecosystem properties. For example, the
whole biomass of wild land mammals before the Quaternary Megafauna Extinction
(c. 0.02 Gt C) is estimated as sevenfold higher than it is today (0.003 Gt C). The
global biomass of humans and livestock (0.16) by far surpasses a recent estimate of
the biomass of wild land and sea mammals of c. 0.007 GT C (Bar-On et al. 2018).
The timeline (Table 1) shows the increasing influence and pressure of humans on
nature, the increasing use of space, and increasing intensity of use. It does not show a
declining dependence of humans on their physical environment since basic requirements have not changed.
We do not have appropriate information about the psychological relationship
between humans and nature in prehistory. The idea that humans once lived in
harmony with nature is a hypothesis without any empirical foundation.
Environmental History
9