However, not only ecology and evolutionary biology are linked to biogeography, but a wide range of disciplines, from geography (9%) to genetics (8%) or conservation (7%).
This is why biogeography involves a wide variety of different methods. Which do we use for what purpose? The questions in biogeography are very diverse, and thus the approaches used may be very different. In the second overview of biogeography, Dawson et al. (2016) said the most common term in the 521 abstracts of the 7th biennial meeting of the International Biogeographic Society was “distribution”. In terms of space, “region” was the most common and in terms of time, “history” or “historical” was the most common, followed by “future”. The word “species” was mentioned in 85% of the abstracts. Biogeography still remains the study of the distribution of species in space and time, despite a widening range of topics. The future of species is one of the major interests, with the history of species distribution.
Figure P.1. Representation of the number of publications according to different keywords.
Source: Web of Science (wcs.webofknowledge.com), March 19, 2021
If terrestrial plant distribution is the main historical beginning of biogeography studies, with the Essai sur la géographie des plantes, written by von Humboldt and Bonpland (1805), the concept was quickly broadened to include other living organisms; see Wallace’s The Geographical Distribution of Animals (1876). After that, progress in taxonomy, systematics and phylogenetics made these studies even broader. New techniques, such as DNA sequencing, ecological niche modeling and many others, have allowed biogeographical approaches to be widened. Dealing with the distribution of Nothofagus (the iconic Southern beech) is not the same as dealing with the propagation of the Ebola virus. Nothofagus has been a key group in biogeographical studies on plants for over 170 years (Cook and Crisp 2005). Despite a huge amount of literature on the subject, the evolution of Nothofagus remains controversial (Hill et al. 2015). On the other hand, the Ebola virus was totally unknown before the 1970s (Pourrut et al. 2005) and, today, drivers that shape the epidemic are much better known, thanks to improvements in approaches and methods (see Chapter 12).
Not only do approaches differ according to the biology of organisms but they also differ according to the environment. Dealing with the biogeography of freshwater fish is not the same as dealing with the biogeography of marine fish. If freshwater habitats can be considered as islands of water in the middle of the land (see Chapter 8), oceans are much less fragmented and more stable environments (see Chapter 9). How should bacterial distribution in the soil be considered? Drivers of community assemblages of bacteria are specific (Fierer et al. 2007). In addition, taxonomic recognition of bacteria involves molecular tools (see Chapter 7). Is the biogeography of water beetles studied in the same way as the biogeography of cave beetles? The drivers of their distribution may not be the same (see, for example, Arribas et al. 2012; Faille et al. 2014), even if both can be considered as in an insular environment.
A lot of very good books on biogeography have been edited; see, for example, the fifth edition of Biogeography (Lomolino et al. 2017), or Conservation Biogeography (Ladle et al. 2011). Most provide the very bases of biogeography, theories and methods, a wide range of approaches, historical and original cases with nice illustrations. And yet, new studies and methodological novelties are coming out every year, and the number and variety make biogeography so attractive and exciting!
In this book, we have chosen to present an overview of biogeography through different specialists, disciplines, particular living groups or ecosystems and challenging topics, trying to cover a wide range of the current studies in such a broad and multidisciplinary science. The biogeography of terrestrial plants and animals is the very basis of the discipline, yet many topics in these two groups remain unstudied. Many books already cover biogeographical studies on plants and animals and these will not be considered in this book.
After a particular overview of the history of biogeography in Chapter 1, in Chapter 2 we will have an intensive study of the challenges and perspectives of the main analytical approaches used in biogeography, an always-changing world. We will then investigate different approaches, such as phylogeography, dealing with the geographical distribution in gene lineages within species or between closely related species (Chapter 3). Another approach we will look at, in Chapter 4, is geophysical, where the geology and climate conditions are put before biotic processes. We will study different ecosystems, such as islands, in Chapter 5. Since MacArthur and Wilson (1967), how can we miss the famous case of island biogeography! Caves (Chapter 6) are also an extreme ecosystem where species develop specific adaptive skills. Soil bacteria (Chapter 7) is almost an unknown world, a world in which much is still to be done in terms of biogeography, and it deserves a specific approach. In the same way, fungi play an essential role in ecosystem processes, and remain largely unstudied. In Chapter 8, we will also explore the biogeography of fungi, reacting differently according to environmental conditions. In Chapters 9 and 10, we will deal with two different environments, that of freshwater biogeography (Chapter 9) and that of marine biogeography (Chapter 10). One is like islands of water in the land, while the other is open areas, where terrestrial approaches are not always applicable. Finally, we will focus on particular approaches that are challenging today and may be of greater importance in the future, such as the biogeography of diseases (Chapter 11), a very current field of research, climate change (Chapter 12) and conservation (Chapter 13), two fields that are also closely linked to the human impact on the distribution of species in space and time.
Biogeography is not only a discipline that has been questioning the evolution of species and ecology since naturalists started exploring the world. Understanding patterns and processes of the distribution of species in space and time may provide solutions to the challenges humanity has faced since the era called the Anthropocene and its consequences, such as the biodiversity crisis and global warming.
July 2021
P.1. References
Arribas, P., Velasco, J., Abellan, P., Sanchez-Fernandez, D., Andujar, C., Calosi, P., Millan, A., Ribera, I., Bilton, D.T. (2012). Dispersal ability rather than ecological tolerance drives differences in range size between lentic and lotic water beetles (Coleoptera: Hydrophilidae). Journal of Biogeography, 39, 984–994.
Cook, L.G. and Crisp, M.D. (2005). Not so ancient: The extant crown group of Nothofagus represents a post-Gondwanan radiation. Proceedings
