Biogeography of a fragmenting world

Abstract

editorial ISSN 1948-6596 Biogeography of a fragmenting world Part of the value of biogeography as a multidiscipli- nary transversal science is its wide applicability to processes that occur at multiple scales. One such process is the extinction of species resulting from the disappearance of their habitats. Habitat loss and fragmentation are widespread, and, together with habitat degradation and other human im- pacts, they probably constitute the aspect of global change that contributes the most to current extinc- tion rates (see, e.g., Sandom et al. 2014), although climate change and biological invasions also play significant roles in changing the ecological dynam- ics of species (see the book reviews by Hinsley 2015 and Cassey 2015 in this issue). Island biogeography is particularly useful for understanding the complex effects of habitat loss and fragmentation on biodiversity, for it provides a solid theoretical background to study and model extinction trends (Harris 1984). Using this concep- tual framework, Matthews (2015) studied different aspects of biodiversity variation in habitat frag- ments, finding that trends in these habitat islands are complex and change from one system to an- other, with traditional island biogeographic rela- tionships only being applicable to a very limited extent. Importantly, some of this lack of transfera- bility can be attributed to the effects of non-native species or the characteristics of human disturb- ance, rather than to a lack of generality of the prin- ciples of island biogeography. Further, the nature and extent of habitat degradation in the matrix surrounding the habitat islands turn out to be im- portant in Matthews’ (2015) research, adding a new dimension to island biogeographic enquiry. High-quality datasets such as the one provided by Bergamin et al. (2015) for the vegetation of the highly fragmented Brazilian Atlantic forest will fur- ther enhance our knowledge about the effects of habitat transformation on biodiversity loss. Islands can also contribute to the study of habitat change and extinctions in that they can act as natural experiments, where isolation has result- ed in the existence of many (pseudo)replicates of limited size with similar ecological conditions and similar but, at the same time, independent evolu- tionary processes and species pools. The work of Lavery (2015) on northern Melanesian mammals is a nice example of how the distribution, ecology and evolution of several groups and lineages can be studied from a holistic, multidisciplinary per- spective in archipelagos and island complexes. This integrative perspective is also adopted for the study of particular biomes, such as the South Afri- can Fynbos (Ojeda 2015), but is particularly difficult when these biomes occupy large areas or are locat- ed in areas with considerable biotic interchange. Some of the complexity of continental set- tings can be untangled by studying areas of inter- mediate isolation, such as peninsulas, and explicitly addressing temporal patterns. The combination of data on past (through pollen) and current distribu- tion of species with macroecological and multivari- ate analyses allow Gavin (2015) to study the stabil- ity of habitats in the Olympic Peninsula (Washington, USA) throughout the end of the Pleistocene and the Holocene. At a larger temporal scale, the macroevolutionary study of extinction risk allows understanding of which species may be more prone to extinction, although habitat loss continues to play a major role in determining which species may be finally lost (DeNeve et al. 2015). Here, the important development of statisti- cal tools to analyse temporal and spatial data (Dale & Fortin 2015, Hartig 2015) allows understanding of trends and drivers from multiple sources of da- ta. A multidisciplinary approach, using transversal frameworks and addressing topics of broad inter- est to biogeographers, can perhaps best account for the many facets of the impacts of global change. This major strength of biogeography is nicely encapsulated by the papers within this issue of Frontiers of Biogeography. Joaquin Hortal 1 and Richard Field 2 Frontiers of Biogeography editors-in-chief Departament of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN-CSIC), 28006 Madrid, Spain. jhortal@mncn.csic.es School of Geography, University of Nottingham, NG7 2RD, UK. richard.field@nottingham.ac.uk frontiers of biogeography 7.2, 2015 — © 2015 the authors; journal compilation © 2015 The International Biogeography Society