Mountains are a perpetual source of inspiration for humankind. For some they are the dwellings of the gods, while others see them as peaks to be conquered. To many their allure lies in their dramatic scenery and the purity of their apparently unspoiled environments or the ancient cultures of their tenacious inhabitants. What is indisputable, however, is that mountains playa vital role in global biogeochemical cycles, and many millions of people across the world depend on them for their livelihoods. In a time of rapid change for the global environment, mountain ecosystems and the people they support are particularly vulnerable.

Of all the world's mountains, the Himalayas have a special status, not just because they contain our planet's highest peak, but because of their enormous extent and the influence they exert on global weather systems. Their presence impacts on the daily existence of the many millions who live in surrounding regions and they have had profound effects on the cultures of those peoples. Even today many parts of the Himalayas remain difficult to access, and they still pose many questions to science, ranging from their origin and the time of their uplift, to the consequences of mountain building on atmospheric circulation and the monsoon, their effects on the development and distribution of fauna and flora, the survival of high altitude life during the Ice Age and the ways that humans have adapted to, and themselves modify, this extreme habitat.

Nepal, right at the centre of the Himalayan Arc, is at the core of these studies. The focus on this country in this monograph yields insights which are of relevance to the entire mountain arc from eastern Afghanistan to Southwest China and between the northern edge of the Ganges lowlands and the Tibetan highlands. This book is the culmination of decades of research by its many authors, and as a statement of the current state of our knowledge of the region and the gaps in our understanding, it lays a firm foundation for future research in the Himalayas. It is a work that is certain to be used and valued for many years to come.

The editors bring immense personal and institutional expertise to this publication. Georg Miehe has almost 40 years of experience in long term ecological studies throughout the Himalayas, and this book is a fitting culmination to those decades of research. Colin Pendry has worked on the Flora of Nepal project for eleven years and the Royal Botanic Garden Edinburgh itself is a centre of excellence in Himalayan studies, with links to the region dating back as far as the' 8th century, and important living and preserved collections from the entire span of the Himalayas. Ram Chaudhary has a similarly long and diverse career as a researcher in the Himalayas, but brings the added dimension of policy formulation, having worked in the National Planning Commission of Nepal.

This volume illustrates the need for a broad- based network of researchers to adequately describe such a complex environment; in this case led by the Philipps-Unlversltat. Marburg and the Royal Botanic Garden Edinburgh. An enterprise of this type relies not least on the long term infrastructure at these institutes and the resources of knowledge and skill that they have accrued over the years. The Philipps Universitat Marburg and the Royal Botanic Garden Edinburgh would like to take this opportunity to stress that the ongoing financial support of the German Research Council (DFG) and the Scottish Government has been indispensable for the success of this project. Ultimately, the trust of our funding agencies in our ability to advance knowledge is the basis for any science and thus has been essential for the production of this book.

In the space of a hundred ages of the Gods, I could not describe to you the glories of the Himalayas." (translated from the Hindu Puranas) From the inception of the Flora of Nepal project at its inaugural meeting in 2002 it was recognised that there needed to be an introductory account which would describe the geographical and ecological context of the 7,000 species of plants which were to be described in the Flora's ten volumes. It was envisaged that such account would give a concise overview of Nepal's physical environment, describe its vegetation types, ecology and conservation, and discuss the history of botanical exploration in the country.

It was fortunate for the project that Georg, with his ecological expertise, decades of research on both sides of the Himalayas and extensive network of contacts, had already seen the need for a book like this and he was able to devote himself to the task of drawing together the many different strands of Himalayan research which are presented here. The volume which has resulted is very much greater in ambition, broader in scope and richer in detail than had originally been conceived. It brings together more than 40 authors who collectively have centuries of research experience in the Himalayas and surrounding regions. It should be seen not only as a statement of our current knowledge of the region, but with its identification of the gaps in this knowledge, it is an explicit call for the research which is needed to further our understanding of the history the region's biota and its future in an uncertain world.

All of the accounts are extensively referenced, and much of the data brought together here was previously not widely available. It is the intention that this volume will act not only as a reference in its own right, but will also improve access to the valuable information in this literature, stimulating a new generation of researchers.

Although this companion volume is not part of the series of taxonomic accounts, the relationship between it and the rest of the Flora of Nepal is close and many of the authors are involved in management of the Flora or in writing accounts for it. This has the advantage of drawing in several Nepalese experts with their crucial local knowledge and expertise, and strengthens the links between international experts and those on the ground. We hope that one aspect of the book's legacy will be the strengthening of these relationships and that it will inspire new collaborations and research. We also hope that it will become a set text both for students and researchers in Nepal and for those elsewhere who share our fascination with the environment and biodiversity of this remarkable region.

The publication of this book would have been impossible without the enormous contribution made by various members of staff at the PhilippsUniversitat Marburg and the Royal Botanic Garden Edinburgh. In particular, we would like to express our heartfelt gratitude to Christiane Enderle who typeset the whole book in addition to creating most of the maps within it, Caroline Muir who oversaw all aspects of the book's design, including its stunning cover, Hamish Adamson whose wide experience in publishing proved vital for the coordination of all aspects of the process, Sebastian Worm for his work on clearing copyrights and Jurqen Kluge for compiling the references. We are very grateful to all those who gave us permission to reproduce their images which do so much to enrich the book. A full list of acknowledgements can be found towards the end of the book.

This companion volume to the Flora of Nepal brings together diverse fields of Himalayan research to present a picture of the environment in which this flora is found, the historical and ecological factors which have created this environment, how it is managed and exploited and some of the threats which it currently faces. All these factors must be considered together because just as the vegetation and ecology of a region are fundamentally shaped by the flora, so the flora in turn reflects its environmental and human impact over time - interactions that have been at the core of our work in the Himalayas for many years. The three elements ofthe book's title - natural history, ecology and human environment - are so closely related to each other that they cannot truly be understood in isolation from each other. We include human impact since human beings have had massive impacts on virtually all habitats within Nepal, and those impacts may well have been wider and more long-lasting than has previously been recognised.

We do not pretend to present a complete regional study, since many important aspects such as economy, transportation and human health are omitted, but instead our focus is on those features which have led to the flora which we see in Nepal today. However, we do not restrict our analysis to Nepal alone, as most of its vegetation types have a wider range in the Himalayan Arc, but instead we aim to describe the vegetation of Nepal in the context of the Himalayas as a whole. Throughout the volume we acknowledge that our understanding is farfrom complete, and we still lack some of the most fundamental information about the origins of the flora. Many questions relating to the date of the origin of the Himalayas, the sequence of events during their orogeny and the processes of speciation, migration and extinction remain unanswered, with different analyses presenting conflicting conclusions. No single discipline can unravel these events, and the only way forward is for more collaborative multi-disciplinary investigations. This volume can be seen as an acknowledgement of our past failures and a plea for more coordinated research in the future.

The early chapters deal with the physical environment of the Himalayas, beginning with Chapter 1 which discusses the regional setting of Nepal within the Himalayan Arc. Chapter 2, Landscapes of Nepal, focusses on the country's very diverse physiographic regions, from the tropical lowlands of the Tarai to the temperate forests of the Himalayas' southern face, and on to the alpine regions and the drier rain-shadow areas behind and between the main ranges. The relationships between altitude, land-forms and precipitation regimes of these zones are discussed and the natural vegetation types which would have prevailed in the absence of human impact are introduced. Chapter 3 discusses Nepal's geology and the tectonic zones which underlie its dramatic geomorphology. The contentious issue of the timing of the orogeny is not described in detail here, but is discussed in greater depth in the account of speciation and uplift in Chapter 8.4.

Chapter 4 is an extensive review of our current state of knowledge about Nepal's climate, describing its seasonality and the topographic variation in thermal and precipitation regimes which are modelled to a level of detail not previously seen, and discussing the local wind systems which can have such dramatic effects on vegetation over short distances. Climate diagrams are used to illustrate the differences across the country but also highlight the paucity of data for much of the country, and the need for longer term measurements both to fully describe Nepal's climate and to test the model discussed in the previous section. The account of daily weather measurements in Langtang and Helambu over a nine month period describes the weather at an unprecedented level of detail for the Himalayas. The relationship between vegetation and subtle variations in climate is nowhere demonstrated more clearly than in the distribution patterns of epiphytes which depend so closely on atmospheric humidity and in the next section this relationship is used to describe the altitudinal belts of the Himalayas. It is widely understood that climate change poses clear threats to the region and the evidence for current climate change and future scenarios is assessed. Glacial fore-field successions are excellent examples of vegetation responses to changes in climate and are considered in the chapter's final section.

Chapter 5 describes the hydrology of the Himalayas, and the relationship between Nepal's rivers, lakes and glaciers and climate, which is of relevance not only within Nepal, but also to the wider region whose water is supplied from the Ganges and thus ultimately the Himalayas. Chapter 6 opens with a discussion of slope stability and its links to plant speciation and goes on to discuss three processes which can lead to major disturbances in the landscape; t earthquakes, giant rockslides and river captures. The rest of the chapter is devoted to discussions of the landforms which characterize the different zones, and the processes which have given rise to them, including erosion, incision of river valleys and glacial processes.

Nepal's soils are described in Chapter 7, with accounts of the main types of soils, their properties and their prevalence in different belts. The degradation or otherwise of Himalayan soils has been a controversial subject in recent decades and it is discussed in the final section.

Chapter 8, entitled Flora, begins with a history of botanical exploration in Nepal and discussion of the resources available for the study of Nepalese plants in herbaria around the world. It goes on to discuss Nepal's phytogeographical links with surrounding regions before analysing contemporary distribution patterns of high altitude species. An important theme is how these distribution patterns were affected by the Himalayan uplift and the Quaternary climatic changes and how these patterns relate to the 'island biogeography' of high altitude habitats, separated from each other by inhospitable environments both upwards and downwards. Migration, dispersal, isolation and in-situ speciation are key issues for the understanding of the natural history of the Himalayas. Thus far the biogeography of the Himalayas has attracted rather little attention in comparison with the Tibetan Plateau or the Andes. The chapter continues with accounts of pteridophytes, bryophytes and lichens, looking at their diversity, ecological significance, the history of their exploration in Nepal and the need for further research in these groups which are all poorly known in comparison with the angiosperms and gymnosperms. The final section of the chapter covers two studies of pollination of Nepalese plants, in the large genus Pedicularis and then in monocots.

Chapter 9 echoes the later sections of the previous chapter and examines Nepal's mycota, discussing the ecological importance of the fungi and the paucity of research on this neglected kingdom.

Chapter 10, Fauna, takes a different approach, and rather than looking at the natural history of Nepal's animals, focuses instead on a description of the speciation processes which have created the diversity we see today. The speciation models illustrated by a wide range of organisms including beetles, spiders, frogs and birds are more advanced than for plants, and it is hoped that this account will stimulate research into the speciation processes of Himalayan plants.

With Chapter 11, People, the focus shifts towards the human dimension with an examination of Nepal's ethnic diversity and the important distinctions in language, subsistence, social order and religion among the ethnic groups of the Tarai, Midlands and Himalayas. As in so many parts of the world, over the course of the last century Nepal has undergone massive social, economic and political changes with concomitant environmental impacts and these are introduced here.

Chapter 12, Ethnobotany, looks at the interactions between people and plants, describing the central role that plants continue to play in economic and cultural activities throughout Nepal.

Chapter 13, Land Use, describes the impact of agriculture, pastoralism and forestry on contemporary landscapes in the country's different regions, and how land use regimes are linked to wider geopolitical events even in the country's most remote regions.

Chapter 14, Environmental History, discusses the historical changes in Nepal's landscapes, detailing the effects of global changes in climate and the emergence of humans as a dominant force throughout the country. Although the paucity of studies to describe these processes continues to be a source of frustration, for the first time we are able to deduce temperature and precipitation changes in the past. The true age and extent of the Himalayan Anthropocene is still uncertain and knowledge about the migration of humans into the Himalayas remains fragmentary. Linguistic analysis combined with genetic data offers another means to understand this process, and is introduced here.

Chapter 15, Ecological Transects, integrates the work of the preceding chapters and describes the vegetation of three regions in terms of their primary ecological factors and the anthropogenic impacts which have so modified these landscapes. We consider the Vegetation Classification presented in Chapter 16 to be one of the most important parts of the book, and it builds upon the pioneering work of Schweinfurth (1957, in German), Stainton (1972, in English) and Dobremez (1976, in French) to present an account of Nepal's vegetation types which combines descriptions of the vegetation with climatic and soil data, human impacts and their phytogeographical links. Since such descriptions can be confusing without a basic understanding of the criteria underlying the classification, its principles are described in detail in the opening section of the chapter.

The final chapter, Conservation, looks at the history of conservation activities in Nepal, recognising that while Nepal has been at the forefront of some developments in conservation, it faces increasing threats from increasing human pressure, climate change, illegal trade and invasive plant species. How Nepal rises to the challenges presented here will determine the future of its biota, but we hope that this book will help to inform and inspire a new generation of researchers whose work will help to support this crucial task.

Throughout the book we rely heavily on photographs to illustrate landscapes and interactions, because a picture remains the best way to convey the complexity of the flora and ecology of a region. For this reason we have laid particular emphasis on the illustration of the vegetation patterns described in Chapter 15 and the vegetation types of Chapter 16.

The survey map (rear cover) includes the names of all Nepalese localities, mountains, rivers and landscapes mentioned in the text, and an inset map shows Nepal's administrative units. Wider Himalayan and High Asian localities, mountains, rivers or landscapes are given in Fig. 1.1. There is a great diversity in the spellings of topographic names across the Himalayan Arc, but we have done our best to unify names. In the case of the Lesser Himalayas, we follow Toni Hagen (1968/69) and Adam Stainton (1972) and use 'Midlands' instead of 'Midhills'. The inner r r cover reproduces the index sheet for the 1 :50,000 and 1 :25,000 maps published by the Government of Nepal in the 1 990s and early 2000s. These maps cover the whole of Nepal and are a tremendous asset for environmental research in the Central Himalayas. Plants are named according to treatments in the Flora of Nepal (Watson et 01. 2011) or the Annotated Checklist of the Flowering Plants of Nepal (Press et 01.2000).

**Contents and Sample Pages**