Gradients in a Tropical Mountain Ecosystem of Ecuador, edited by Erwin Beck, Jörg Bendix, Ingrid Kottke, Franz Makeschin, Reinhard Mosandl. Berlin, Germany: Springer, 2008. xxii + 522 pp. Ecological Studies Series, Vol 198. € 179.95. ISBN 978-3-540-73525-0.
The Northern Andes are recognized as one of the most biodiverse regions in the world, as well as one of the most threatened. It is imperative, then, that we understand better how tropical Andean ecosystems are changing, what the consequences will be, and how different forms of land use and management might lead to a more sustainable future. However, there is a problem. Mountain ecosystems are extremely heterogeneous, at a variety of scales. Biodiversity, with its own spatial and temporal variability, overlies the inherent environmental heterogeneity, and is then modified by variable land use practices. Of course, all these factors interact in a complex way. How do we even begin to explore such complexity?
In 1997 the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) launched a research project at the Reserva Biológica San Francisco (RBSF, run by Nature and Culture International) in the southern Andes of Ecuador, near Podocarpus National Park. The idea was to focus on a core area of about 1000 ha and bring together German and Ecuadorian multidisciplinary teams to work on the complexities of the local Andean ecosystem—a zone of evergreen mountain rain forest, with shrub and dwarf bamboo páramo at the highest altitudes.
The editors of this book have attempted to address the complexity of this mountain ecosystem through the work of 104 researchers in around 30 research groups. Clearly, this is quite a challenge, given that many less ambitious edited volumes fail to deliver a coherent theme. Here, the theme is gradients. Natural and induced heterogeneities at the local scale are linked together by means of a set of interacting natural and human activity gradients. The natural gradients include a vertical altitudinal gradient (1850–3100 m asl) and a horizontal gradient (a 30 km long transect at 1950 m asl representing transitions in humidity). Biodiversity sits within these natural gradients, but is affected by human activity gradients, corresponding to forest clearance practices, agriculture, and subsequent recovery after abandonment.
The introductory chapters describe the study area and the limitations of our knowledge of mountain rain forests in this part of the Andes. The interesting cultural background in this region is also explained. Contrasts are drawn between the indigenous Shuar community, traditionally practising shifting agriculture below 1000 m asl, the distinctive Saraguro community (resettled by the Incas from the Titicaca region of Bolivia) with mixed cultivation and cattle at mid-altitudes, and the numerically dominant mestizos—mostly colonists from elsewhere in southern Ecuador since the 1960s—growing cash crops and grazing livestock. The ‘modernization’ of these 3 communities and the conflicts between them are key factors in explaining the land use practices in different parts of the gradients, and acknowledging these differences is vital to developing socially compatible land management solutions.
The second section sets up the rest of the book by explaining the difficulty of studying a megadiverse ecosystem in a complex natural and cultural setting. The bulk of the volume presents the studies themselves, arranged into themes relating to the various gradients. For example, climate, soils, flora, fungi, fauna, water relations, nutrient status, biotic soil activities, forest stand structure, and plant growth are all investigated in relation to the altitudinal gradient. Spatial and temporal heterogeneity patterns are also described. Natural disturbances (forest gap dynamics, landslides) are contrasted with those caused by human activities (eg sustainable and non-sustainable use of natural resources, slash-and-burn forest clearance, construction of roads and power lines). Other studies assess natural and enhanced regeneration of cleared and abandoned land.
The final chapter attempts to summarize the main findings of the work and identify key themes for the future. The use of fire as an agricultural tool has caused some significant problems, not least the apparently irreversible changes in vegetation cover from forest to bracken following slash-and-burn forest clearance. There are avenues worth exploring: to manage pastures more effectively, enhance existing forests, and regenerate abandoned pastures with socially and economically valuable trees. The way biodiversity interacts with ecosystem processes is still unclear and is another line of research for the future.
The many illustrations throughout the book are clear and informative. Colour diagrams and photographs are used to communicate complex ideas clearly and succinctly. Evidently, considerable attention has been invested in the visual representation of findings and ideas. For me, this investment paid off, and those responsible deserve praise for a job well done.
So, who should buy this book? It is expensive, and although I can see university libraries investing in a copy, I am not convinced many Latin American libraries or individuals will be in a position to buy one. The book is targeted at those interested in ecosystem studies and sustainable land management and resource use, but only one ecosystem is described and evaluated. To what extent is the RBSF study area typical of the wider situation in the Andes and mountains elsewhere? The limited information available for other areas makes this a difficult question to answer, but also highlights why the question is so important. The potential to apply findings from a well-funded research programme to areas with less available information is worth attention. Disappointingly, there are only limited attempts to address this in the book.
The individual studies frequently cross-reference to other chapters in the book. The editors and authors deserve credit for such comprehensive internal referencing, which helps considerably in tying together the various strands of research. However, wider contextual referencing is more variable, and a large number of relevant studies are not cited, even some very local to the study area. As examples of the kinds of references I was expecting—and acknowledging that there is no particular reason to cite these here rather than many others equally deserving of mention—I could point to the works of Keating (1995 onwards), Jokisch and Lair (2002), Buytaert et al (2006) and Keese et al (2007). Schneider (2004) reported remarkably similar bracken invasion in response to agricultural burning in the Yucután region of Mexico; and this is just one illustration of the links with other geographical areas that would have provided context and made the book more explicitly useful to a wider range of readers.
Despite these reservations, this book provides unrivalled detail for the region where the work was carried out, and acts as a model for investigation aimed at evidence-based management planning elsewhere. Many of the broad issues are commonly experienced in other parts of the Andes (and other mountains), as is the complexity of the problems and potential solutions. Although the detail may not transfer to other regions, some of the key ideas almost certainly will, albeit with modification. On this basis, I would recommend it to anyone interested in the complexities of mountain ecosystems, not just in the Andes.
The good news is that the DFG has already funded a follow-up programme in the same place: “Biodiversity and Sustainable Management of a Megadiverse Mountain Ecosystem in South Ecuador.” This time, the emphasis is on transferring the research into effective land management actions. Hoping that this latest project finds room to look at the transferability of the outcomes to other places, I await the next volume with anticipation.