Volume 35, Issue 2 p. 752-753
Book Reviews
Free Access

Connecting Landscapes for Conservation in a Changing World

Ezequiel González

Corresponding Author

Ezequiel González

Institute for Environmental Science, University of Koblenz-Landau, Landau in der Pfalz, 76829 Germany

Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Praha - Suchdol, 165 00 Czech Republic

Address correspondence to E. González email: [email protected]

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First published: 16 February 2021

Corridor Ecology. Linking Landscapes for Biodiversity Conservation and Climate Adaptation. 2nd edition. Hilty, J. A., A. T. H. Keeley, W. Z. Lidicker Jr., and A. M. Merenlender. 2019. Island Press, Washington, D.C., U.S.A. xvi + 350 pp. US$42.00 (paperback). ISBN 978-1-61091-951-3.

Essentials of Landscape Ecology. With, K. A. 2019. Oxford University Press, Oxford, .K. xii + 641 pp. US$65.00 (paperback). ISBN 978-0-19-883839-5.

Life on Earth has been continuously changing, but in the past centuries, the intensity and rate of these changes have drastically increased, leading to biodiversity declines in practically all ecosystems (Ostberg et al. 2015; Newbold et al. 2019). From all the global threats to biodiversity, land-use change and climate change are among the most important, and their relevance is likely to increase in the future (Titeux et al. 2016). In this context, organisms need to move, in the short term to disperse and colonize new habitats or forage for resources and in the long term in response to the changing conditions of their original habitats. Two ecological subdisciplines deal closely with these topics: corridor ecology and landscape ecology. Two recent books cover these disciplines with different focuses and levels of detail. Essentials of Landscape Ecology is clearly aimed at ecologists and students of landscape ecology, whereas the authors of Corridor Ecology write for a broader readership, ranging from students and scientists to policy makers and conservationists. Nevertheless, both books lean on classical ecological theory and recent literature to share knowledge.

The second edition of Corridor Ecology, by Hilty et al., comes almost 15 years after the first one and brings more than an update of the relevant literature. The authors have a solid scientific background in corridor and landscape ecology together with ample experience in conservation, which is a valuable combination for the type of message they want to deliver. The structure of the book is slightly different from the first edition, but I am unsure if this is useful. Although the same sections can still be distinguished, some changes in the order of the chapters are not always logical. The first section focuses on the ecological principles, theory, and concepts of the ecology of corridors. It starts with a clear and concise description of habitat loss, fragmentation, and climate change, which leads one to the conclusion that animals and plants need habitat connectivity in order to persist. Then, the authors present ecological theory of populations and communities living in fragmented and isolated habitat mosaics. Mathematical models are used to explain some of these theories in detail, and while this might be hard to follow for some readers, the explanations in the text are simple. After setting the foundation, the next chapters detail how to achieve connectivity through the use of corridors. By showing examples of different corridors, the authors highlight what one needs to consider when planning for a corridor in terms of the expected goals, the focus on different levels of biodiversity, and the potential ways to measure connectivity and efficiency. The examples and concepts are diverse and go from traditional corridors that increase structural connectivity in an attempt to benefit many species to those designed using species-level information on movement and functional connectivity. Increasing connectivity can also bring unexpected results, and a series of examples provide a warning on how edge effects, invasive species, environmental filtering, and genetic erosion can cause negative consequences.

Only two parts near the end of the book are entirely new additions. One is about how species deal with climate change and how conservation strategies might help them. Whether by maintaining well-connected climate analogs or guaranteeing the conservation of climate refugia (locations that better buffer climate change), climate-wise connectivity is needed. The second presents an interesting topic that seems to be advancing fast: ecological connectivity in the ocean. As an insect ecologist myself, I never thought about connectivity in this context and how to achieve it. Carr and Hazen, the invited authors of this chapter, provide several examples of how new technologies allowed the understanding of both pelagic and coastal connectivity, point out how marine corridors can have a key role for conservation, and warn about the current threats these ecosystems face. The closing chapter provides an applied perspective on how to implement and conserve corridors, including a review of the motivations and incentives for landowners to preserve their land. These concepts are supported by seven examples of existing corridors from around the world, covering different scales, ecosystems, and management strategies, which, in addition to a research agenda for the future, is a good and optimistic way to end the book.

In Essentials of Landscape Ecology, Kymberly A. With summarizes her extensive experience in researching and teaching landscape ecology, accompanied by great artwork, in a well-written and clear textbook that will likely make it a frequently consulted source of information for landscape ecology courses. Each chapter starts with a guiding question or statement and closes with future research directions, a list of concise summary points, and a set of discussion questions that can stimulate further reading and thinking. Many examples from several groups of organisms and different geographical regions are provided throughout the text, which helps to elucidate the concepts. A remarkable addition is a quotation in each chapter that highlights its key messages. Some of these are from classical authors and cornerstone studies, but others are from recent works, showing how the discipline is constantly developing.

Scale is a central concept in landscape ecology, so the choice of scaling issues as a starting point is well justified. Along with the implications of temporal and spatial scales, hierarchical systems in biology and landscape ecology are described and set the groundwork for the rest of the book. Landscape heterogeneity and dynamics and their links with disturbances are explored using several case studies to illustrate why heterogeneity has a central role in landscape ecology. The discussion on landscape pattern analysis is much more technical, offering an overview of the methods and available data sources to calculate the widely used metrics of landscape composition and configuration and to perform spatial analyses.

In the chapter “Landscape Connectivity,” the differences between Corridor Ecology and Landscape Ecology become clear: in the latter more emphasis is put on patch- and landscape-scale connectivity measures and the ecological theories behind the assessment of connectivity are discussed in detail. Landscape effects on different ecological levels are described using a combination of theory, classical, and novel methods to assess them and case studies to demonstrate these issues. The presentation of different approaches for modeling movement and population ecology and methods for studying landscape genetics is especially useful. The chapter on population spatial spread includes a subsection on landscape epidemiology, a topic that certainly has become relevant due to the Covid-19 pandemic. Effects on communities and ecosystems are complex subjects than can be addressed from multiple perspectives. Several of them are clearly explained, although some recent but highly relevant syntheses of the influence of landscape-driven changes on biodiversity are missing (e.g., Tscharntke et al. 2012). In my opinion, after such an impressive amount of information, a concluding section presenting a broad perspective of the current situation would have been useful. This, however, might be out of the scope and objective of the book.

As to the visual appearance, artwork, and use of images, these two books stand at opposite extremes. Corridor Ecology uses rather simple diagrams and graphics, mainly from previously published articles, and illustrative photos to show examples. While the former generally improve comprehension of particular concepts, the black and white photographs do not make a substantial contribution. In Essentials of Landscape Ecology, the text and figures are tightly connected, making the figures an important part of the book. Furthermore, the colored illustrations are visually attractive and help one understand the described concepts. Considering the size and price of the two books, it does not seem that artwork makes a big price difference. But it does in making the reading experience more stimulating, and I believe that the extra care devoted to these elements in Essentials of Landscape Ecology paid off.

It is beyond doubt that there is an urgent need to increase efforts to conserve biodiversity and the ecosystem services humans obtain from it. Although corridors are useful tools for conservation, some argue that their minimum width should be 2 km (Beier 2019). This is unrealistic in many regions, considering that farmland covers almost 40% of the terrestrial surface of our planet (Foley et al. 2011). That is why I think the future of conservation needs to incorporate recent lessons from landscape ecology, but they should be combined with socioecology and government incentives and regulations. This interdisciplinary approach can ensure the continued existence of heterogeneous landscapes, together with an ecological intensification of agriculture that can help maintain biodiversity at larger scales.