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Über dieses Buch

Mountain regions occupy about a quarter of the global terrestrial land surface and provide goods and services to more than half the humanity. Global environmental change threatens the integrity of these systems and their ability to provide the goods and services upon which humanity has come to depend. This book gives an overview of the state of research in fields pertaining to the detection, understanding and prediction of global change impacts in mountain regions. More than 60 contributions from paleoclimatology, cryospheric research, hydrology, ecology, and development studies are compiled in this volume, each with an outlook on future research directions.

Inhaltsverzeichnis

Frontmatter

Introduction: The International Year of Mountains Challenge and Opportunity for Mountain Research

Introduction: The International Year of Mountains Challenge and Opportunity for Mountain Research

Mountains are complex and fragile ecosystems characterised by vertically, highly differentiated climatic conditions and often by an abundance of water and rich biodiversity. Mountains are high-risk environments: avalanches, glacial lake outbursts, landslides and earthquakes threaten life in mountain areas. Remoteness and difficult access hamper development in mountain regions. Therefore, mountain areas are often marginalized. Despite these constraints, mountains offer significant opportunities. Mountain dwellers have adapted to life in steep and harsh conditions and have developed sophisticated techniques for farming, water use, forestry and communication. The agro-biodiversity as a function of altitude, exposition and farmers’ crop selection is huge. Mountain inhabitants have also developed a rich cultural diversity. Therefore, people living in lowland areas or in big cities increasingly prefer mountains for recreation.

Thomas Hofer

Paleoenvironmental changes

Frontmatter

A Dynamical Perspective on High Altitude Paleoclimate Proxy Timeseries

Mountain paleoarchives, including glaciers, laminated lake sediments, and trees near the limits of their habitable range, provide much information relevant to the study of past climatic changes (Alverson and Kull 2002). Properties recorded in these archives offer quantitative climate-related information at annual or higher temporal resolution. In addition, by nature of their occurrence at high elevation, they provide information about climate variability in the free atmosphere, not just its surface expression. However, interpreting these proxy records in terms of large-scale climatic change is a difficult task. Mountains are generally regions of strong climatic gradients and inherently high natural variability, making interpretation of local records difficult. Additional difficulties exist due to the fact that the proxies do not respond to climate alone, but are influenced by myriad additional factors. In this chapter, we highlight two methods which use dynamical constraints, either from the climate system or the underlying archives themselves, to help tease out the climatic information contained in point-based proxy timeseries. Although the examples that we present are applied in conjunction with ice core records, the techniques are relevant to the interpretation of annually resolved climate proxy timeseries in high altitude regions. Past climatic changes are often either reconstructed using paleoproxy data or modeled using a numerical representation of the underlying dynamics of either the climate system or paleoarchive development.

Keith Alverson, Christoph Kull, G. W. K. Moore, Patrick Ginot

Understanding the Spatial Heterogeneity of Global Environmental Change in Mountain Regions

One of the challenges for global environmental change research is to understand how future climate changes will be expressed in mountain regions. The physiographic complexity of mountains creates environments that can be highly variable over relatively short distances. This spatial heterogeneity reflects a hierarchy of environmental controls. At regional scales, insolation and atmospheric circulation features determine the dominant regional climate patterns that affect mountain regions. At finer spatial scales, substrate, aspect, elevation, and a number of other environmental factors influence ecosystem dynamics. Vegetation, for example, is affected by all levels of this hierarchy, from regional-scale climate regimes down to site-specific features, such as substrate type (cf. Körner, this volume).

Sarah L. Shafer, Patrick J. Bartlein, Cathy Whitlock

Ice Cores from Tropical Mountain Glaciers as Archives of Climate Change

The 20

th

century has seen the acceleration of unprecedented global and regional-scale climatic and environmental changes to which humans are vulnerable, and by which we will become increasingly more affected in the coming centuries. One-half of the Earth’s surface area lies in the tropics between 30°N and 30°S, and this area supports almost 70% of the global population. Thus, temporal and spatial variations in the occurrence and intensity of coupled ocean-atmosphere phenomena such as El Niño and the Monsoons, which are most strongly expressed in the tropics and subtropics, are of worldwide significance. Unfortunately, meteorological observations in these regions are scarce and of short duration. However, ice core records are available from low-latitude, high-altitude glaciers, and when they are combined with high-resolution proxy histories such as those from tree rings, lacustrine and marine cores, corals, etc., they provide an unprecedented view of the Earth’s climatic history over several millennia. This paper provides an overview of these unique glacier archives of past climate and environmental changes on millennial to decadal time scales. Also included is a review of the recent, global-scale retreat of these alpine glaciers under present climate conditions, and a discussion of the significance of this retreat with respect to the longer-term perspective, which can only be provided by the paleoclimate records.

Lonnie G. Thompson, Mary E. Davis, Ping-Nan Lin, Ellen Mosley-Thompson, Henry H. Brecher

The Contribution of Cosmogenic Nuclides to Unraveling Alpine Paleoclimate Histories

Moraines are non-continuous short-term records of ice marginal positions. Moraines help provide important paleo-glaciological mass balance information (e.g. glacier surface area, ice volume, terminus elevation, snowline altitudes, longitudinal ice surface gradient below the paleo-snowline) which in part controls the geometry of the glacier and the rate of advance and retreat of an ice margin. Therefore, chronologies on these ancient glacial landforms can be directly tied to local paleo-temperature and paleo-precipitation estimates for specific times during and after a glaciation. In the past two decades, the terrestrial cosmogenic nuclide (TCN) exposure dating method has made a revolutionary contribution to the study of alpine paleo-glacial histories and paleoclimatology. (i) Exposure dating of boulders on moraines provides the time since a boulder was deposited from an ice margin. It directly determines when the glacier reached a measurable mass-balance condition, whereas other chronometers, such as radiocarbon, U-series, and luminescence dating, typically provide only minimum or maximum limiting ages on ice margin positions, (ii) The method can provide a precise estimate of the timing of initial ice retreat. Timing of when an alpine glacier reaches its maximum position is not only a function of local climate but also of numerous glaciological and hydrological conditions. Initial retreat is the most discrete short-lived climate-response event in a moraine record. Unlike the timing of initial retreat, initial advance is not recorded in moraine records because glaciers override their moraines during advance (Gibbons et al. 1984).

John C. Gosse

Holocene Glacier Fluctuations and Winter Precipitation Variations in Southern Norway

Glacier fluctuations provide important information on climate variations as a result of changes in the mass and energy balance at the Earth’s surface. Variations in glacier mass balance (e.g. Paterson 1994) are the direct reaction of a glacier to climatic variations. Fluctuations in the length of valley and cirque glaciers, on the other hand, are the indirect, filtered, and commonly enhanced response. Available mass balance records are, however, relatively short compared to the longer records of glacier length variations.

Atle Nesje, Svein Olaf Dahl, Øyvind Lie, Jostein Bakke

Glacier and Climate Variability in the Mountains of the Former Soviet Union during the last 1000 Years

Pollen analysis,

14

C and lichenometric dating of moraines, former elevations of the upper tree limit, and dendroclimatological and limnological data are some of the most relevant proxies for the reconstruction of climate variability and glacier behavior during the last millennium. A considerable number of paleoclimate reconstructions exist for the mountains of the Former Soviet Union. In this paper, we provide a regional overview of these datasets. Only regions with chronologically controlled and, preferably, high-resolution reconstructions will be considered here, namely, the Khibiny, the Urals, the Cherskogo Range, the Putorana Plateau, the Birranga Mountains, the Suntar-Khayata, the Kamchatka, the Caucasus, the Pamir-Alay, the Tien Shan, and the Altay Mountains (Fig. 1). This paper is a brief summary of the glacier and climate history of the last millennium and identifies achievements as well as gaps in our knowledge of paleoclimate in these regions. Ultimately, the identification of regional patterns of past climate changes will allow us to gain a better understanding of the causes behind climate variability on inter-annual to centennial timescales.

Olga N. Solomina

Glacier-Climate Models as Palaeoclimatic Information Sources: Examples from the Alpine Younger Dryas Period

The regional distribution of precipitation in a mountain range like the European Alps is a good indicator for continental-scale atmospheric circulation patterns. This is particularly true when precipitation is primarily caused by the advection of air masses to the Alps from the North Atlantic or the Mediterranean Sea, as is the case under cold conditions. Alpine precipitation patterns during the Lateglacial period can hence be interpreted in terms of past atmospheric circulation patterns in continental Europe. In this paper, glacier-climate models are used for the reconstruction of Younger Dryas precipitation patterns based on changes in equilibrium line altitudes of Alpine glaciers. This type of research provides important information concerning the range of past precipitation variability against which present climatic changes in the Alps can be assessed. Also, unravelling the spatial patterns of Alpine precipitation allows us to gain a better understanding of forcing mechanisms behind precipitation changes.

Hanns Kerschner

Holocene Environmental Change in the Himalayan-Tibetan Plateau Region: Lake Sediments and the Future

The South Asian Monsoon system is one of the most important and influential of the Earth’s major climate systems. The people of the most heavily populated Asian countries have adapted many aspects of their society to the subtleties of the monsoon rains, and are thus highly susceptible to small changes in the timing and intensity of monsoon precipitation. A monsoon failure can have disastrous effects, and flooding related to extreme monsoon rains has proven to be one of the most deadly of natural catastrophes (e.g. in Bangladesh, China, India and Nepal). These vulnerabilities are likely to increase in the future with continued population growth, intensified land-use and sea-level rise. Although there is a growing effort to improve seasonal to interannual monsoon prediction skills via new research, the largest threats to human health and livelihood could come from unanticipated decade- and longer-scale extremes in monsoon. A major goal of this paper is to summarize the state-of-the-art regarding century to millennium-scales of monsoon variability, and to identify the paleoenvironmental research that is most urgently needed in the Himalayan-Tibetan Plateau if society is to be served effectively in the 21

st

century.

J. Overpeck, K. B. Liu, C. Morrill, J. Cole, C. Shen, D. Anderson, L. Tang

Water Resources in the Arid Mountains of the Atacama Desert (Northern Chile): Past Climate Changes and Modern Conflicts

The Atacama Desert of the Central Andes (18°S to 28°S) has become a focal point of environmental research in recent years. Indeed, this area is a key site in several respects. It is located between the tropical and extratropical precipitation belts; the vertical gradients of ecozones range from sea level at the Pacific Coast up to high mountains that reach into the mid-troposphere at 6000 m elevation. The prominent mountain chain of the Andes stretches N-S, perpendicular to the zonal westerly airflow of the mid-latitudes, which creates distinct environmental gradients at meso-and micro-scales. Due to their sensitive location at the juncture between tropical and extratropical climate zones, paleoclimate records from this area may potentially provide important insights into the dynamics of the large-scale atmospheric circulation in the Central Andes in the past. This region therefore provides an ideal natural laboratory for paleoclimatologists.

Martin Grosjean, Heinz Veit

Palaeolimnological Investigations in the Alps: The Long-Term Development of Mountain Lakes

Most mountain lakes and their catchments are, due to their remoteness, less impacted by human actions than lakes in lowland regions. They are, therefore, often considered pristine systems. Nevertheless, even remote, uninhabited areas are polluted via atmospheric deposition of aerosols that transport acid rain, heavy metals, organic compounds, and nutrients.

André F. Lotter

High Mountain Lakes and Atmospherically Transported Pollutants

Remote mountain lakes, whether found at high altitudes or high latitudes, usually appear to be in pristine condition. In particular, those lakes that are situated above or beyond the tree-line are rarely disturbed by agricultural or forestry practices and few if any people inhabit their catchments. However, recent research indicates that even the most remote lakes are impacted by atmospherically transported pollutants, and that greenhouse-gas forced climate change is beginning to have a significant influence on ecosystem functioning. UV-B radiation is also increasing and, in interaction with global warming, may already be changing biogeochemical cycles in many mountain lakes (Vinebrooke and Leavitt, this volume). All sites are subject to multiple stresses, and studies of the ecological response of mountain lakes to such combined stress need to consider interactions between all factors, both natural and anthropogenic. In this chapter, we consider acid deposition, toxic substances and climate change as the three main drivers of ecosystem change in high mountain lakes.

Richard W. Battarbee, Simon Patrick, Martin Kernan, Roland Psenner, Hansjoerg Thies, Joan Grimalt, Bjoern O. Rosseland, Bente Wathne, Jordi Catalan, Rosario Mosello, Andrea Lami, David Livingstone, Evzen Stuchlik, Vera Straskrabova, Gunnar Raddum

Trace Metals, Fly-ash Particles and Persistent Organic Pollutants in European Remote Mountain Lakes

Many anthropogenic pollutants emitted to the atmosphere can be transported over large distances and affect ecosystems and human health thousands of kilometres from their source. In recent years, concern has grown over the increased contamination of remote areas, particularly the Arctic and mountain regions, and the unprecedented levels of pollutants observed in areas previously considered to be pristine. Atmospheric transport is one of the most efficient and rapid means by which toxic pollutants, including trace metals and persistent organic pollutants (POPs), can be transferred to remote areas. Understanding the pathways and mechanisms from source to sink is thus vitally important. Atmospheric transport models predict that sources of pollutants to remote areas are widespread and diverse, such that there are contributions from “local” and regional sources, as well as transboundary and even global inputs (e.g. Hanisch 1998).

Neil L. Rose, Handong Yang, Pilar Fernández, Joan O. Grimait

Long-term Responses of Mountain Ecosystems to Environmental Changes: Resilience, Adjustment, and Vulnerability

The steep environmental gradients of mountain ecosystems over short distances reflect large gradients of several climatic parameters and hence provide excellent possibilities for ecological research on the effects of environmental change. To gain a better understanding of the dynamics of abiotic and biotic parameters of mountain ecosystems, long-term records are required since permanent plots in mountain regions cover in the best case about 50–70 years. In order to extend investigations of ecological dynamics beyond these temporal limitations of permanent plots, paleoecological approaches can be used if the sampling resolution can be adapted to ecological research questions, e.g. a sample every 10 years. Paleoecological studies in mountain ecosystems can provide new ecological insights through the combination of different spatial and temporal scales. If we thus improve our understanding of processes across both steep environmental gradients and different time scales, we may be able to better estimate ecosystem responses to current and future environmental change (Ammann et al. 1993; Lotter et al. 1997).

Willy Tinner, Brigitta Ammann

Climate Fluctuations Derived from Tree-rings and Other Proxy-records in the Chilean Andes: State of the Art and Future Prospects

Treeline and high elevation sites in the central and southern Chilean Andes (32°39′ to 55°S) have shown to be an excellent source of paleoenvironmental records because their physical and biological systems are highly sensitive to climatic and environmental variations. In addition, most of these sites have been less disturbed by logging and other human induced disturbances, which enhances the climatic signals present in the proxy records (Luckman 1990; Villalba et al. 1997).

Antonio Lara, Alexia Wolodarsky-Franke, Juan Carlos Aravena, Ricardo Villalba, Maria Eugenia Solari, Liliana Pezoa, Andrés Rivera, Carlos Le Quesne

Biogeographical Consequences of Recent Climate Changes in the Southern Andes of Argentina

Long-term trends of temperature variations across the Southern Andes (37–55°S) have been recently examined using a combination of instrumental and proxy records. Tree-ring based reconstructions indicate that the annual temperatures during the 20

th

century have been anomalously warm across the Southern Andes in the context of the past four centuries. The mean annual temperatures for northern and southern Patagonia during the interval 1900–1990 are 0.53°C and 0.86°C above the AD 1640–1899 means, respectively. Increased temperatures are seriously impacting the physical and biological systems across the Southern Andes.

Ricardo Villalba, Mariano H. Masiokas, Thomas Kitzberger, José A. Boninsegna

Cryospheric changes

Frontmatter

Mountain Glaciers in Global Climate-related Observing Systems

Fluctuations of glaciers and ice caps in cold mountain areas have been systematically observed for more than a century in various parts of the world and are considered to be highly reliable indications of worldwide warming trends (cf. Fig. 2.39a in IPCC 2001). Mountain glaciers and ice caps are, therefore, key variables for early-detection strategies in global climate-related observations. Advanced monitoring strategies integrate detailed observations of mass and energy balance at selected reference glaciers with more widely distributed determinations of changes in area, volume and length; repeated compilation of glacier inventories enables global representativity to be reached (IAHS(ICSI)/UNEP/UNESCO 1989; 1998; 2001; cf. Haeberli et al. 2000; 2002).

Wilfried Haeberli

Mountain Glaciers are at Risk of Extinction

Mountain glaciers are a product of climate and are important environmental components of local, regional and global water cycles. Glaciers are sources of beauty in the mountain landscapes and, in many cases, have been among the primary agents responsible for forming these landscapes. Glacier mass balance data have received increasing attention in recent years because of their usefulness in detecting climate change and explaining rising sea level (Meier 1984; Church et al. 2001). Understanding changes in glacier volume is important for regional water supply and power generation. In addition, observations made by the scientific community, tourists and climbers have shown that alpine glaciers are disappearing from mountain ranges around the globe. These changes have profound implications for sources of fresh-water on land, cause sea-level rise and make mountains less attractive, and more difficult and less appealing to climb (Bowen 2001; Meier and Wahr 2002; Meier et al. 2003).

Mark B. Dyurgerov

Low Latitude Glaciers: Unique Global Climate Indicators and Essential Contributors to Regional Fresh Water Supply. A Conceptual Approach

Greenhouse gases in the atmosphere trap energy and, if their concentrations increase, e.g. from anthropogenic sources, the aggregate energy of the earth system increases as well. As a consequence, intensities of fluid dynamic processes (atmosphere and oceans), phase changing processes, biochemical processes, and the thermal status of the system will change in a complex and highly interactive manner. Manifold changes in local, regional and global climate are therefore to be expected, but are anything but easy to detect because: Firstly, climate itself is characterised by multi-scale dynamic variability of interacting processes and states. Thus, trends, fluctuations or changes can only be analysed for selected parameters and must be extracted from noise. Secondly, instrumental records, which concentrate on isolated parameters, are limited in time, and proxy-indicators, although covering longer time scales, show complex dependencies on climate, which can be difficult to interpret unequivocally. This paper emphasizes the role of low-latitude glaciers as i) climate proxies and ii) climate-dependent freshwater sources.

Georg Kaser, Christian Georges, Irmgard Juen, Thomas Mölg

Glaciers of the Tropical Andes: Indicators of Global Climate Variability

Over the last decade, mass balance has been monitored on several glaciers of the tropical Andes by the Institute of Research for Development (IRD, France) in collaboration with South American partners. This network includes glaciers in the Cordillera Real of Bolivia, Zongo and Chacaltaya (16°S), glaciers in the Cordillera Blanca of Peru, Yanamarey and Artezonraju (9°S), and glaciers in the eastern and western cordilleras of Ecuador, Antizana (0°28’S) and Carihuayrazo (1°S) (Fig. 1). Some of these have been listed as benchmark glaciers by the Word Glacier Monitoring Service (WGMS 2001), and the data are accessible to the scientific community. This network is designed to capture the effects of climate change, and especially ENSO variability, both in the outer (Bolivia, Peru) and the inner (Ecuador) tropical Andes. Glaciers have been selected to be representative of the regional glacierization. Each monitoring programme includes two glaciers, a large one (1 km

2

or more) with a substantial accumulation zone, and a small one that is more directly sensitive to ablation processes. Information about the long-term evolution of some of these glaciers has been extracted from aerial photographs, available for the last five decades (Francou et al. 2000; Ramirez et al. 2001). The particular nature of climate in the Tropics allows ablation to occur at anytime throughout the year in the lowest part of glaciers. Thus, the ablation zone has been surveyed in monthly intervals at several sites, providing interesting details about the seasonal response of tropical glaciers (Francou et al. 2003).

Bernard Francou, Pierre Ribstein, Patrick Wagnon, Edson Ramirez, Bernard Pouyaud

Glacier Recession in the Peruvian Andes: Climatic Forcing, Hydrologic Impact and Comparative Rates Over Time

Tropical glaciers are intriguing and apparently rapidly disappearing components of the cryosphere that literally crown a vast ecosystem of global significance. Half of the Earth’s surface area lies between the tropics of Capricorn and Cancer, wherein a staggering 75% of the global population resides (Thompson 2000). Tropical glaciers are highly sensitive to climate changes over different temporal and spatial scales, notably ENSO, and are important hydrological resources in tropical highlands (Francou et al. 1995; 2000; this volume; Wagnon et al. 2001; Kaser and Osmaston 2002). Moreover, resolving the complex dynamics and variability of the tropical climate over longer time periods presents important goals to the global modelling community. Compiling an accurate understanding of the timing and climate response of tropical glaciers in the past is a crucial source of palaeoclimatic information for the validation and comparison of climate models (e.g. Farrera et al. 1999; Hostetier and Clark 2000; Porter 2001; Harrison et al. 2002; Seltzer et al. 2002). Deciphering the relative strength of different climatic forcing mechanisms on tropical glacier behaviour and quantifying hydrological changes associated with glacier recession are therefore relevant to interpreting the past climate and predicting the impact of future climate changes. Much scientific, social and political attention now concerns future changes in climate, with temperature change predominant.

Bryan G. Mark, Geoffrey O. Seltzer

Climate Change, Mountain Permafrost Degradation and Geotechnical Hazard

The IPA Circum-Polar Permafrost Map (Brown et al. 1997) shows discontinuous and sporadic permafrost in the mountains of Europe, including Scandinavia, the Alps, the Pyrenees, and further east in the Urals. In general, the lower altitudinal limit of mountain permafrost increases with decreasing latitude, from sea level in Svalbard, to around 1500 m in Southern Norway, to above 2500 m in the southern Swiss Alps. Many of these low-latitude mountain regions have permafrost temperatures that are only a few degrees below zero, so that a slight shift in energy flux at the ground surface is likely to cause a significant increase in the depth of summer thawing and, in consequence, widespread permafrost degradation. Where permafrost is ice-rich, degradation caused by global warming is likely to be associated with increased magnitude and frequency of mountain slope instability (Harris et al. 2001a). Traditional landslide hazard assessment approaches, based on forward projection of historical data on distribution and magnitude-frequency relationships (Varnes 1984), may therefore become increasingly inappropriate if climate change leads to a significant change in the thresholds of processes within the permafrost geomorphic system. In this paper, approaches to the assessment of geotechnical hazards associated with mountain permafrost in a warming climate are outlined in the context of recent European collaborative research. A critical first stage is the early detection of permafrost responses to climate change through integrated monitoring systems.

Charles Harris

Glacier and Permafrost Hazards in High Mountains

Glacier- and permafrost-related hazards represent a continuous threat to human lives and infrastructure in high mountain regions. Related disasters can kill hundreds or even thousands of people at once and cause damage with a global sum on the order of 10

8

Euro annually. Glacier and permafrost hazards in high mountains include:

outbursts of glacier lakes, causing floods and debris flows;

ice break-offs and subsequent ice avalanches from steep glaciers;

stable and unstable glacier length variations;

destabilisation of frozen or unfrozen debris slopes;

destabilisation of rock walls; and

combinations or chain reactions of these processes.

Andreas Kääb, John M. Reynolds, Wilfried Haeberli

Impact of Climatic Changes on Snow Cover and Snow Hydrology in the French Alps

A better understanding of the potential effects of climate change on snow cover is critical, considering the far-reaching environmental and socio-economic implications on water resources, winter tourism, ecology as well as local changes in climate. The snow coverage of the French Alps depends on weather conditions in a rather complex way. For a given winter, snow cover is the consequence of the various meteorological events encountered (frequency and intensity of snowfall events, atmospheric circulation patterns, cold and warm periods). Simple relationships between snow cover and averaged climate variables, such as mean temperature and precipitation, can therefore not adequately explain interannual variability of snow cover. Models can be used to gain a better understanding of the complex interactions between different climate variables and their effects on snow cover. In addition, models are of great interest for the assessment of potential climatic change impacts.

Eric Martin, Pierre Etchevers

Modelling the Response of Mountain Glacier Discharge to Climate Warming

Glaciers are characteristic features of mountain environments but are often not recognized for their strong influence on catchment runoff quantity and distribution. Such modification occurs with glacierization of only a few percent of the total catchment area, and affects adjacent lowlands far beyond the limits of mountain ranges. The main impact occurs because glaciers temporarily store water as snow and ice on many different time scales (Jansson et al. 2003), the release from storage being controlled by both climate and internal drainage mechanisms.

Regine Hock, Peter Jansson, Ludwig N. Braun

Hydrological changes

Frontmatter

Orographic Precipitation and Climate Change

More than half of the accessible freshwater is used directly or indirectly by humankind, and much of this precious resource has its origin in mountainous regions, ultimately in the form of orographic precipitation. In many areas, mountains function as “water towers” for the surrounding regions. Melt from snow cover and glaciers represents an important contribution to runoff in the surrounding areas, especially during seasons when precipitation is sparse or completely absent. Mountain freshwater resources are heavily utilized for agricultural purposes (e.g. irrigation) and for the generation of hydropower, thus being of great socio-economic importance. Yet, heavy orographic precipitation events also represent a potential hazard, as they may lead to floods, avalanches and mudslides that often cause countless loss of life and tremendous damage. The potential consequences of such events may be extreme. For instance, a single catastrophic mudslide event that took place in Venezuela on December 15, 1999, is estimated to have caused more than 20,000 casualties according to re-insurance estimates.

Christoph Schär, Christoph Frei

Monitoring Climate Variability and Change in the Western United States

Mountain ecosystems of the western United States are complex, and include cold desert biomes, such as those found in Nevada, subpolar biomes found in the upper treeline zone, and tundra ecosystems, occurring above timberline. Many studies (e.g. Thompson 2000) suggest that high elevation environments, comprising glaciers, snow, permafrost, water, and the uppermost limits of vegetation and other complex life forms are among the most sensitive to climatic changes occurring on a global scale. The stratified, elevationally-controlled vegetation belts found on mountain slopes represent an analogue for the different latitudinally-controlled climatic zones, but these condensed vertical gradients are capable of producing unique hotspots of biodiversity, such as those that serve as habitat for a variety of species ranging from butterflies, frogs and toads, to species of birds, trout and salmon. High relief and high gradients make mountain ecosystems very vulnerable to slight changes of temperatures and to extreme precipitation events (Parmesan 1999; Pounds et al. 1999).

Henry F. Diaz

Spatial Heterogeneity of Snow Conditions and Evapotranspiration in the Swiss Alps

In most alpine regions, the presence of snow controls the hydro-climatic situation over a great part of the year. The delayed and long-lasting process of snowmelt guarantees a relatively well-balanced discharge regime of rivers in the spring and summer melting season, even if only a small part of their catchment includes high mountain areas. For the typical alpine weather conditions, this results in high melt water runoff during dry conditions when net radiation and air temperature are high, while, during cooler periods, rainfall compensates for reduced or discontinued melt rates and sustains streamflow at a balanced level. Furthermore, because of the relatively high albedo of snow, changes in alpine snowcover are associated with a feedback to climate, a process that has not yet been very well investigated. For example, a climate-induced decrease in snowcover will reduce surface albedo, which leads to an amplification of the initial warming.

Lucas Menzel, Herbert Lang

Runoff Processes in Mountain Headwater Catchments: Recent Understanding and Research Challenges

Runoff generation in mountain catchments is one of the most complex hydrological processes. It is highly variable in space and time, depending on the combination of three main controlling factors: (1) climate, (2) soil and geology, and (3) vegetation. The different combinations of these three factors determine the water balance of landscape units, including soil moisture dynamics, evapotranspiration and runoff generation. When assessing runoff generation, not only the runoff amounts need to be considered, but also the relative streamflow contributions of surface and subsurface runoff, which may differ considerably between areas (Buttle 1998). An overview of runoff mechanisms and components in different environments is given in Uhlenbrook and Leibundgut (1997) and Bonell (1998). The main focus of this paper is on subsurface stormflow, the least understood flow component.

Alfred Becker

Runoff Generation Processes on Hillslopes and Their Susceptibility to Global Change

Global change will influence hillslope hydrological processes for a variety of reasons. On the one hand, climate change might alter the hydrological input, i.e. precipitation and snow melt, which might cause an increase or decrease in the intensity of specific hillslope processes. For instance, overland flow might be amplified by increased rain intensities (Horton 1933) or by reduced infiltration due to surface crusts (Yair 1990) or increased hydrophobicity (Doerr et al. 2002), triggered by longer and more pronounced drought periods. However, overland flow could also be significantly influenced by antecedent moisture conditions of the substrate that were either altered due to wetter climate and reduced evapotranspiration at a site or due to different snow and snow melt regimes, changing the hydrological input for a specific precipitation event. On the other hand, global change in the form of land use changes will play a key role in defining the dominant runoff generation processes on hillslopes (cf. summary given in DVWK 1999).

Stefan Uhlenbrook, Jens Didszun, Chris Leibundgut

Identifying Space-time Patterns of Runoff Generation: A Case Study from the Löhnersbach Catchment, Austrian Alps

Runoff generation is a result of the interplay of a range of processes, the relative magnitudes of which vary, among other things, with climate, catchment properties, and catchment scale. The variability of runoff generation processes within a mountain catchment and the variability from event to event is one particularly intriguing aspect. A better understanding of these spatio-temporal patterns of runoff generation is critical for obtaining realistic model simulations of events, such as extreme floods, and of run-off behaviour associated with changes in environmental and land use conditions. Estimating runoff generation is very difficult as it involves a high degree of extrapolation. Difficulties in accurately assessing runoff in mountains have been highlighted by local-scale field experiments (e.g. Scherrer 1997), observations in experimental basins (e.g. Anderson et al. 1997; Kirnbauer and Haas 1998; Torres et al. 1998; Müller and Peschke 2000; Uchida et al. 2001), and modelling studies (e.g. Moore and Grayson 1991) that emphasize the spatially highly heterogeneous nature of runoff. Also, different runoff processes may dominate at different spatial scales (see e.g. Blöschl 1996; Uhlenbrook and Leibundgut 1997). Although it is possible to estimate runoff for yet unobserved situations with hydrological simulation models, the reliability of such estimates is notoriously poor, particularly when moving from the plot scale or small catchment scale to medium sized catchments (DFG 1995). There is still a gap between the understanding of runoff generation processes at the plot scale and process-based hydrological modelling at the catchment scale.

Robert Kirnbauer, Günter Blöschl, Peter Haas, Gabriele Müller, Bruno Merz

Soil Erosion and Runoff Generation Related to Land Use Changes in the Pyrenees

Many scientific papers and books demonstrate the direct and indirect effects of human activities on the intensification of soil erosion processes and changes in both sediment and runoff sources (Ives and Messerli 1989). It is well known that deforestation and hillslope farming cause distinct changes in soil properties and infiltration rates, which ultimately affect soil erosion processes and the hydrological cycle at a basin and hillslope scale (Goudie 1986).

José M. García-Ruiz, Teodoro Lasanta, Blas Valero, Carlos Martí, Santiago Beguería, Juan I. López-Moreno, David Regüés, Noemí Lana-Renault

The Role of Riparian Zones in Steep Mountain Watersheds

The riparian zone encompasses the strip of land between the stream channel and the hillslope and is sometimes referred to as the valley floor, near-stream zone (Cirmo and McDonnell 1997), floodplain (Bates et al. 2000), or buffer zone (Lowrance et al. 1985). Riparian zones have been differentiated from upslope zones by unique hydrology, topography, vegetation, and soils (Hill 1996). Characteristics such as anoxic zones, gleyed soils, distinct soil color, high organic content, breaks in slope, and near-surface water tables often distinguish riparian zones from adjacent hillslopes. Because of their location, riparian zones have significant potential to regulate the movement of water and elements in surface and subsurface runoff that flows from upslope areas to the stream (Hill 1996).

Brian L. McGlynn

The Use of Hydrological Models for the Simulation of Climate Change Impacts on Mountain Hydrology

According to the Second and Third Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC 1996; 2001) the increase in mean surface air temperature of the northern hemisphere was larger in the 20

th

century than in any other period of the last 1000 years. The decade 1990–1999 was the warmest of this time period. It is also believed that this increase in air temperature will be accompanied by intensification of the global hydrological cycle and, in the same chain of cause and effect, by enhanced evaporation and precipitation (Schär and Frei, this volume). However, the scientific community needs to gain a better understanding of the biosphere-atmosphere system before being confident on the predictions of hvdrolodcal processes in a future climate (Frei et al. 2000: Ohmura and Wild 2002).

Joachim Gurtz, Herbert Lang, Mark Verbunt, Massimiliano Zappa

Effects of Climate Variability and Change on Mountain Water Resources in the Western U.S.

The western U.S. derives its water resources predominantly from cold season precipitation and storage in snowpack along the narrow Cascades and Sierra ranges, and the Rocky Mountains. Hydroclimate is modulated by the diverse orographic features across the region. Precipitation and runoff generally peak during winter and spring respectively, whereas water demand is highest during the summer. Such phase differences between water supply and demand create a necessity for water management, which is reflected by major developments of reservoirs and dams that regulate irrigation, hydropower production, and flood control during the past 50 years. Because water resources have been essential to the economic development and environmental well being of the western states, it raises concerns when recent studies suggest that global warming may exert significant impacts on snowpack and streamflow, which may seriously affect water resources in the western U.S. in the 21

st

century (e.g. Leung and Ghan 1999; Leung and Wigmosta 1999; Mile et al. 2000; Leung et al. 2003a; Miller and Kim 2000).

L. Ruby Leung

Ecological changes

Frontmatter

The Green Cover of Mountains in a Changing Environment

Slopes induce biological diversity, and nowhere else is diversity so important as on slopes. Why the first? Why the second? The inclination of a piece of land causes gravitational forces that structure the surface and climatic vectors that differentiate life conditions across those structures. The resultant multitude of microhabitats leads to a multitude of inhabitants. A major function of those inhabitants is to secure substrate against further action of gravity. Sloping terrain is only as stable as the workforce keeping it in place. It is this endless battle between the force of gravity and biological safeguards against its consequences, which governs mountain biota. If the substrate is gone, so too are most of the plants and animals.

Christian Körner

The Response of Alpine Plants to Environmental Change: Feedbacks to Ecosystem Function

Alpine ecosystems occur on all continents, and potentially serve as sensitive indicators of biotic response to environmental change. Because environmental change associated with resource extraction and development is minimal in most alpine areas, biotic changes in the alpine are reflective of “indirect” anthropogenic environmental effects, including changes in climate, atmospheric chemistry, and transmission of ultraviolet radiation. Plant species respond differentially to these environmental changes, related in part to their ability to alter growth rates as resource supply changes and to changes in biotic interactions with neighbors (Theodose and Bowman 1995; Callaway et al. 2002). Thus, changes in plant species composition are likely to herald environmental change in the alpine. Floristic changes have been noted in some alpine areas, potentially associated with climate change (Grabherr et al. 1994), atmospheric pollution (Rusek 1992), and increased N deposition (Korb and Ranker 2001; see Baron et al., this volume for aquatic biotic responses to N deposition).

William D. Bowman

Ecological Climate Impact Research in High Mountain Environments: GLORIA (Global Observation Research Initiative in Alpine Environments) — its Roots, Purpose and Long-term Perspectives

High mountain ecosystems are sensitive to climate change (Box 1). Historical records of the flora on high summits in the Alps provide an important baseline against which climate-induced effects on high mountain ecosystems can be assessed. Reinvestigations of these old “monitoring summits” have shown that mountain plants have migrated upwards during the 20

th

century. An increase of atmospheric temperatures since the late 19

th

century is the most likely cause of this upward shift (Gottfried et al. 1994; Grabherr et al. 1994; 1995; 2001a; Pauli et al. 1996; 2001a). This “summit study” underlined the importance of long-term monitoring for assessing climate change effects on mountain ecosystems and initiated the establishment of extensive monitoring networks in mountain environments.

Harald Pauli, Michael Gottfried, Daniela Hohenwallner, Karl Reiter, Georg Grabherr

A Global Assessment of Mountain Biodiversity and its Function

The montane and alpine regions of the world cover about 10% of the terrestrial area, a life zone ca. 1000 m above and below the climatic treelines in temperate and tropical latitudes, including some of the biologically richest ecosystems. The alpine life zone above the climatic treeline hosts a vast biological richness, exceeding that of many low elevation biota and covers 3% of the global terrestrial land area (Körner 1995). The overall global vascular plant species richness of the alpine life zone alone was estimated to be around 10,000 species, 4% of the global number of higher plant species. No such estimates exist for animals but based on flowering plants, high elevation biota are, as a general rule, richer in species than might be expected from the land area they cover.

Eva M. Spehn, Christian Körner

Potential Impacts of Global Change on Vegetation in Australian Alpine Landscapes: Climate Change, Landuse, Vegetation Dynamics and Biodiversity Conservation

The alpine and subalpine regions of south-eastern mainland Australia are small and restricted, covering an area of only approximately 11,000 km

2

in a continent of 7.7 million km

2

(Williams and Costin 1994; Costin et al. 1999; Williams et al. 2003). The most extensive are the Kosciuszko plateau in New South Wales (NSW), the Bogong High Plains in Victoria, the Central Plateau in Tasmania and the mountains of south-west Tasmania (Kirkpatrick 1994; 1997; Williams and Costin 1994; Costin et al. 1999). These areas are of prime importance as catchments for the supply of high quality water to adjacent lowlands; for hydroelectricity generation; for recreation in both summer (e.g. walking, horse riding) and winter (mainly skiing); and for nature conservation. In Victoria and Tasmania, the high country is also used for the summer grazing of domestic cattle. Because of their unique combination of geomorphic, biotic and land-use characteristics, and despite their limited distribution, Australia’s high mountain regions are of national and international significance (Kirkpatrick 1994). In recognition of this, most of the Australian Alps are designated National Park.

Richard J. Williams, Carl-Henrik Wahren

Ecological Effects of Land-use Changes in the European Alps

In many mountain regions, there have been dramatic changes in agricultural land use in recent decades. In some cases, these are related to changes in technology, such as the increased use of machine harvesting of hay or a switch from one breed of grazing animals to another. In other cases, the trend has been to abandon agriculture on less productive and least accessible land (Lambin et al. 1999). In the European Alps, for example, 16% of all farm holdings were abandoned within ten years (1980–1990). In addition, almost 70% of the farms that are still in operation today are run only as a secondary source of income. With regard to the land use issue, this means that an average of about 20% of the agricultural land of the Alps has been abandoned, and in some areas as much as 70% (Tappeiner et al. in press). In contrast, farming in the better agricultural locations is being intensified. Hence, land-use changes are considered to be a major driving force behind changes in landscape patterns, ecosystem function and dynamics in Europe (MacDonald et al. 2000).

Erich Tasser, Ulrike Tappeiner, Alexander Cernusca

Climate Interactions in Montane Meadow Ecosystems

Climate change can alter ecosystems and thereby trigger feedback effects that can either enhance or retard the climate change (Lashof et al. 1997). Such feedbacks are especially likely in montane and high-latitude ecosystems where soils are carbon-rich (Whittaker 1975; Schlesinger 1997), ecotones are prevalent as a result of topographic variability, vegetation is sensitive to climatic variables such as snowmelt date and length of growing season (Körner 1992; Harte and Shaw 1995; Goulden et al. 1998), and climate change is expected to be large due to snow-albedo feedback (Groisman et al. 1994). Predicting the chronology and magnitude of such feedbacks is a major challenge in ecology today, as well as an important issue both for global climate change science and policy and, locally, for people whose livelihood is dependent upon montane climatic and ecological regimes.

John Harte

High Elevation Ecosystem Responses to Atmospheric Deposition of Nitrogen in the Colorado Rocky Mountains, USA

The rapid rise in human populations and technological advances since 1850 have caused changes in several global scale biogeochemical cycles, including the global nitrogen cycle. The Haber-Bosch process to convert atmospheric nitrogen gas (N

2

) to ammonia (NH

3

) is now almost universally used to fertilize food crops. The production of nitrogen oxides (NO

x

) from combustion for industrial purposes, energy production, and transportation is the other large source of reactive nitrogen to the atmosphere. Combined, these two human alterations have added approximately 140 Tg N yr

1

to the global reactive N pool, a value that now exceeds natural source contributions of about 100 Tg N yr

1

(Galloway and Cowling 2002).

Jill S. Baron, Koren R. Nydick, Heather M. Rueth, Brenda Moraska Lafrançois, Alexander P. Wolfe

Mountain Lakes as Indicators of the Cumulative Impacts of Ultraviolet Radiation and other Environmental Stressors

High elevation lake ecosystems are regarded as potentially sensitive indicators of global change because of their cold and dilute abiotic environment, low biodiversity, poor functional redundancy, and relative lack of local human perturbations (Skjelkvâle and Wright 1998; Sommaruga 2001; Battarbee et al. 2002; Psenner et al. 2002). Mountain lakes located near treeline are expected to be the most responsive to long-term impacts of stratospheric ozone depletion and increased flux of solar ultraviolet-B radiation (UV-B; 290–320 nm), climatic warming, and other stressors because of sharp transitions in control processes (Fig. 1) associated with vegetation development and snowpack albedo (Vinebrooke and Leavitt 1998; 1999a; Fyke and Flato 1999). As detailed below, increased flux of solar UV-B and global warming may be already interacting to restructure food webs and biogeochemical cycles in many mountain lakes (Leavitt et al. 1997; Sommaruga-Wögrath et al. 1997).

Rolf D. Vinebrooke, Peter R. Leavitt

The Role of Mid-latitude Mountains in the Carbon Cycle: Global Perspective and a Western US Case Study

The International Geosphere Biosphere Program report on mountain ecosystems stresses the potential role of mountainous regions in the Earth’s geophysical cycles (Becker and Bugmann 2001). However, mountain environments have rarely been addressed specifically in studies of terrestrial carbon dynamics. Although it was first suggested that the US carbon sink was localized in eastern US forests (Fan et al. 1998), more recent studies that partition the US sink into specific regions suggest that a significant fraction is located in the western US (Schimel et al. 2000; Pacala et al. 2001 ; Schimel et al. 2002). As increasing development puts pressure on arable lands in North America and Temperate Asia, forests and other high carbon storage ecosystems are increasingly relegated to mountain landscapes. Inspection of recent land cover databases (e.g. IGBP or DeFries et al. 2000) shows clearly that in Temperate North America, Europe and China, a large fraction of forested landscapes is found in major and minor mountain ranges. Figure 1 shows an index of carbon uptake in forests based on forest cover from satellite observations (Defries et al. 2000) and growing season length (with longer growing seasons indicating a higher carbon uptake potential). Growing season lengths are scaled to eddy covariance estimates of carbon uptake per growing season day (Falge et al. 2002). Since the majority of current terrestrial sinks are found in the Northern Hemisphere mid-latitudes, montane forests have the potential to contribute significantly to current carbon sinks.

David Schimel, B. H. Braswell

Remote Sensing Detection of High Elevation Vegetation Change

A striking change associated with modern human society has been the increase in atmospheric CO

2

due to the increased burning of fossil fuels (coal, petroleum, natural gas) since the industrial revolution (Sarmiento and Siegenthaler 1992; Sarmiento and Bender 1994). One potential consequence of this atmospheric change is the so-called “greenhouse effect”, a global climatic warming induced by elevated atmospheric CO

2

modifying the atmosphere’s opacity to infra-red radiation. Because CO

2

is an essential component of plant photosynthesis, an increase in ambient CO

2

levels immediately leads to the question as to whether these changes might be altering plant function globally and might also be changing vegetation patterns.

Herman H. Shugart

Monitoring Networks for Testing Model-Based Scenarios of Climate Change Impact on Mountain Plant Distribution

In recent years, predictive modelling of plant species’ distribution has been shown to be a powerful method for obtaining preliminary assessments of potential ecological impact of rapid climatic change (e.g. Brzeziecki et al. 1995; Kienast et al. 1996; Saetersdal and Birks 1997; Iverson and Prasad 1998; Lischke et al. 1998; Gottfried et al. 1999; Guisan and Theurillat 2000; 2001; Bakkenes et al. 2002). Such models give static results: they reveal where suitable species’ habitats might be located in a climatically changed future, but they do not explicitly consider all the processes leading to the predicted changes. A basic assumption behind their application is thus to consider present and future distributions of species to be in equilibrium, or at least in pseudo-equilibrium, with their environment (Guisan and Theurillat 2000). Although this assumption obviously does not hold in all ecological situations, scenarios obtained from these models nevertheless constitute an interesting spatially-explicit and quantitative basis for discussing how climate change might impact plant distribution. Examples of such discussions are provided in the next section.

Antoine Guisan, Jean-Paul Theurillat

Projecting the Impacts of Climate Change on Mountain Forests and Landscapes

Mountain forests fulfil a multitude of functions, including the provision of timber, fuelwood, edible and medicinal plants, the storage of carbon, the purification of air and water, the regulation and reduction of peak streamflow, the protection from natural hazards, and the contribution to the aesthetic beauty of the landscape. The importance of these functions varies greatly from one mountain region to the other, but in some way, forested landscapes and their fate under a changing climate are important for the capability of mountain regions to provide many of the goods and services that humanity depends on.

Harald Bugmann, Bärbel Zierl, Sabine Schumacher

Assessing Climate Change Effects on Mountain Ecosystems Using Integrated Models: A Case Study

Mountain systems are characterized by strong environmental gradients, rugged topography and extreme spatial heterogeneity in ecosystem structure and composition. Consequently, most mountainous areas have relatively high rates of endemism and biodiversity, and function as species refugia in many areas of the world. Mountains have long been recognized as critical entities in regional climatic and hydrological dynamics but their importance as terrestrial carbon stores has only been recently underscored (Schimel et al. 2002; this volume). Mountain ecosystems, therefore, are globally important as well as unusually complex. These ecosystems challenge our ability to understand their dynamics and predict their response to climatic variability and global-scale environmental change.

Daniel B. Fagre, Steven W. Running, Robert E. Keane, David L. Peterson

Detecting Global Change at Alpine Treeline: Coupling Paleoecology with Contemporary Studies

Mountain ecosystems provide unique opportunities to detect and understand global change impacts due to their strong altitudinal gradients coupled with the presence of parks and biosphere reserves in many mountain areas where direct human impacts are minimal (Graumlich 2000; Becker and Bugmann 2001). Alpine treeline, the distinctive boundary between forest and tundra on high mountains, has been a particularly important focus of this research. While alpine treeline can appear to be a simple ecotone and thus a ready indicator of changing temperatures, a rich history of research has revealed that the dynamics of treeline are complex. Issues of lags and inertia, as well as multiple drivers across diverse scales abound. In this essay, we outline key issues for understanding alpine treeline in the context of global climate change. While our views strongly reflect research that has been done in the temperate zone, particularly in North America, the questions underlying the interpretation of treeline are applicable to many biotic indicators of climate change.

Lisa J. Graumlich, Lindsey A. Waggoner, Andrew G. Bunn

Human Dimensions

Frontmatter

The Risks Associated with Climatic Change in Mountain Regions

The Earth’s environment is continuously subjected to various stresses through natural processes and human interference. With the rapid industrialization and population growth that the 20

th

century has experienced worldwide, however, humankind has added a new dimension of stress to the global environment in general, and mountain regions in particular. In some instances, environmental degradation is inevitable because of the basic requirements of human populations, particularly where those are growing rapidly; in other cases, environmental damage is a direct result of mismanagement and over-exploitation of natural resources (Beniston 2000). The sensitivity of a given mountain region to changes in environmental conditions depends largely upon the climatic, geological and biological features of the region considered. Changes in these controlling factors, particularly through direct human interference or indirect effects such as climatic change, may have significant impacts upon numerous mountain environments.

Martin Beniston

Forests in Sustainable Mountain Development

In 2000, the Task Force on Forests in Sustainable Mountain Development of the International Union of Forestry Research Organizations (IUFRO) published a state-of-knowledge report (Price and Butt 2000). The terms of reference for the Task Force recognized the need for such a report, deriving from four linked trends:

a widespread shift in the science and practice of forestry, from an emphasis on the production of wood towards integrated management recognizing that forests serve multiple functions and produce a wide range of goods;

changing expectations regarding the roles of mountain forests among populations around the world, in an increasingly urbanized global society;

rapid rates of change, both perceived and measured, in the cover and uses of forests and adjacent ecosystems in mountain regions around the world;

the growing recognition of the global importance of mountain ecosystems and their inhabitants.

Martin F. Price

Institutional Dynamics and Interplay: Critical Processes for Forest Governance and Sustainability in the Mountain Regions of Northern Thailand

The main argument of this paper is that changes in the formal and informal institutions that govern natural resources in mountain regions of northern Thailand have been critical for environmental changes, livelihoods and sustainability. Over the past decade, there have been new insights from interdisciplinary research on how societies interact with environmental changes in mountain regions. These have underlined the importance of institutions as both causes and responses to environmental change, and how institutions themselves arise from the way environmental and sustainability problems are constructed. In this chapter, these more general findings will be illustrated primarily through examples from recent and ongoing research in the mountain region of Northern Thailand. Taken together, these various studies challenge long-held beliefs about what constitutes problems in environmental change and sustainability, underline the need for a better understanding of cross-scale interactions, and point the way towards a more open and accountable science in support of sustainability.

Louis Lebel

State Simplifications of Land-Use and Biodiversity in the Uplands of Yunnan, Eastern Himalayan Region

Uplands, mountains, or highlands are both biogeographic and cultural terms that refer to mountainous areas, their biological components and agricultural practices (Sajise and Baguninon 1982). In public perception, mountain regions are often associated with geographical and socio-political peripheries, due to their often remote locations, their higher proportion of ethnic minorities, their landuse and livelihood practices, and their political status. The preamble to Chapter 13 of Agenda 21 states the importance of mountain ecosystems as follows:

“Mountains are an important source of water, energy and biological diversity. Furthermore, they are a source of such key resources as minerals, forest products and agricultural products and of recreation. As a major ecosystem representing the complex and interrelated ecology of our planet, mountain environments are essential to the survival of the global ecosystem. Mountain ecosystems are, however, rapidly changing. They are susceptible to accelerated soil erosion, landslides and rapid loss of habitat and genetic diversity. On the human side, there is widespread poverty among mountain inhabitants and loss of indigenous knowledge” (Menzies 2002).

Jianchu Xu, Andreas Wilkes

Mountain Biodiversity, Land Use Dynamics and Traditional Ecological Knowledge

Traditional mountain societies are characterized by their close interconnection with nature and natural resources. They depend upon natural resources and biodiversity for their sustainable livelihood concerns (Ramakrishnan 1992a; Ramakrishnan et al. 1994; 1996). This linkage with nature and natural resources extends beyond the economic realm; social, cultural and spiritual dimensions also play a significant role (Ramakrishnan et al. 1998). Traditional mountain societies have a holistic view of the ecosystem and the social system. This relationship with nature is based on coexistence rather than competition, which results in agricultural strategies that are adapted to the natural environment and the sustainable use of natural resources. The result of this relationship is a set of institutional arrangements that evolved towards ecological prudence. The ultimate objective is the sustainable use of natural resources through compromises between environmental risks on the one hand, and productivity concerns on the other.

P. S. Ramakrishnan

Land Use Intensification around Nature Reserves in Mountains: Implications for Biodiversity

Many mountain environments are experiencing increases in population density and are undergoing rapid intensification of human land uses, such as recreation, resource extraction, agriculture, and housing. One consequence of increasing human impact is the alteration of nature reserves, many of which are in mountain regions. While nature reserves are generally well-protected within their borders (Bruner et al. 2001), evidence is mounting that many reserves are nonetheless losing native biodiversity (Newmark 1987; 1995; 1996; Woodroffe and Ginsberg 1998; Brooks et al. 1999). A contributing factor is the conversion of surrounding habitats for agriculture, logging, settlements, and other human activities (Sala et al. 2000). We suggest that human land use activities outside the boundaries of reserves both affect and are affected by nature reserves, so that the true system boundaries span far outside the designated boundaries (Fig. 1). In this review, we examine the complex interactions among socioeconomic systems, land use, biophysical factors, and biodiversity within and around reserves and point out research needs.

Andrew J. Hansen, Ruth S. DeFries

Nature Conservation Value of European Mountain Farming Systems

High nature value (HNV) farming areas are regarded as farmland where there are intimate relationships between farming practices and biodiversity and where the continuation of those farming practices is essential for the maintenance of this biodiversity value (e.g. Bignal 1998; Luick 1998; Ostermann 1998; Webb 1998; Zervas 1998). By the mid 1990s, there was a growing recognition that particular farming systems (many of them in mountainous areas) were important in maintaining nature conservation value over much of the wider European countryside, but it was also recognised that there was little information available on the range of such systems being practised across Europe. To redress some of this imbalance, the UK Joint Nature Conservation Committee and the World Wildlife Fund (WWF) funded a pilot study of nine European countries: Greece, France, Hungary, Ireland, Italy, Poland, Portugal, Spain and the United Kingdom (Beaufoy et al. 1994; Bignal et al. 1994b; Bignal and McCracken 1996a,b; 2000).

David I. McCracken, Sally Huband

Economic Globalisation and its Repercussions for Fragile Mountains and Communities in the Himalayas

This essay deals with the repercussions of rapid economic globalisation for mountain environments and communities in the Hindu Kush-Himalayan (HKH) region. The subject, despite its importance, has not received systematic attention beyond the protests and debates by Non-Governmental Organisations (NGOs) and others (Roy 1997). We present the information and understanding generated by a recently concluded exploratory study on the subject supported by the Mac Arthur Foundation (Jodha 2002). After discussing the key features of the rapid economic globalisation in the HKH region, we examine how mountain-specific conditions (mountain specificities), such as fragility, inaccessibility, diversity, and marginality, interact with the globalisation process. We identify the risks and opportunities created by globalisation for mountain areas and communities. The prognosis that derives from our discussion is supported by emerging evidence from selected mountain areas of China, India, Nepal, Pakistan and Bangladesh (Jodha 2002).

N. S. Jodha

Research Partnerships for Mitigating Syndromes of Global Change in Mountain Regions

Key problems in mountain areas and at highland-lowland interfaces are largely related to human impact in these fragile ecosystems and may be intensified by the indirect effects of human activities in surrounding lowland areas. On the positive side, mountain regions are the world’s freshwater reservoirs; they are important areas for agriculture, have resources that can be exploited for mining and tourism, and exhibit great biodiversity within small areas. The combined effects of various key problems in a mountain area can lead to a so-called “mountain syndrome”; most mountain systems show key symptoms of this syndrome or have the potential for their development (NCCR North-South 2000). The syndrome concept, developed by the German Advisory Council for Global Change (WBGU 1996), provides a framework for focused research. Its basic assumption is that typical clusters of ecological, social and economic problems or symptoms can be identified in specific regions of the world, such as mountain areas. These typical problem clusters are called “syndromes of global change” and are seen by WBGU (1996) as representative, specific functional patterns of non-sustainable development. Given this assumption, the syndrome concept allows primarily for integrated, situation-specific differentiation of global change.

Hans Hurni, Hanspeter Liniger, Urs Wiesmann

Monitoring and Modelling for the Sustainable Management of Water Resources in Tropical Mountain Basins: The Mount Kenya Example

The Upper Ewaso Ng’iro North river basin, which drains the north-western slopes of Mount Kenya in central Kenya, epitomises the African highland-lowland system. Extending over a vast region (15,200 km

2

), it encompasses an extreme eco-climatological gradient that ranges from the glaciated peaks and indigenous forests of Mount Kenya to the semi-arid and arid land of the lowland plains (Fig. 1). The mountain forms a great natural asset in terms of water resources with plentiful rainfall (1500 mm/yr) supplying perennial rivers that radiate lifelines to the dry lowlands below. Thus, Mount Kenya is one of the major “water towers” (Liniger et al. 1998b; Liniger and Weingartner 2000) in Eastern Africa. Increasing pressures on the mountain from population increase and agricultural development have the potential to endanger this asset and cause conflict between upstream and downstream water users (Hurni et al., this volume). Rapid population growth has attained levels as high as 7–8% per annum (Kiteme et al. 1998). Migrants initially moved to the lower mountain slopes, attracted by good soils, high rainfall and proximity to rivers and transport, but latterly, forced by the pressure for land, they have settled on the dry plains, extending the migration zone into marginal areas for production (Kiteme et al. 1998; Liniger et al. 1998a).

Lindsay MacMillan, Hans Peter Liniger

Challenges in Mountain Watershed Management

People living in mountain regions are discovering that managing watersheds for local needs is no longer a viable option. External pressure from the lowlands adds substantially to the difficulties of trying to sustain the resources used by local indigenous populations. These problems are best exemplified by addressing the hydrological and water quality issues that emerge from a combination of natural processes and the integrated effects of all land-use activities.

Hans Schreier

Overcoming the Vertical Divide: Legal, Economic, and Compensation Approaches for Sustainable Management of Mountain Watersheds

Sustainable water development and the mitigation of large-scale natural disasters in river basins depend in large measure on the ways in which upstream water sources and soils are protected. Environmental services provided by mountains are often only noticed when they are lost, as in the case of downstream floods caused by upstream deforestation. As half of humanity depends on fresh water that originates in mountain watersheds, protecting environmental services provided by mountain regions is highly important for lobal environmental security.

Maritta R. v. Bieberstein Koch-Weser

Future Research Directions

This book provides a snapshot of Global Change research in the world’s mountain regions. It results from the increased awareness of mountain issues that was generated during the International Year of Mountains 2002. Similar to a photograph, it represents only one part of reality and does not aim to include all aspects of Global Change research in mountains in a single compilation. To provide a panorama view, the book compiles examples of prominent recent mountain research in both natural and social sciences. An important and recurring theme of this book is the need for an integrated approach to mountain research involving stakeholders and policy-makers besides natural and social scientists. Such an approach pays attention to the complexity of mountain regions not only in terms of the strong environmental gradients along mountain slopes, but also in terms of socio-economic gradients associated with varied access to limited resources and rapidly changing land-use, economic and political circumstances.

Astrid Björnsen, Ulli Huber, Mel Reasoner, Bruno Messerli, Harald Bugmann

Backmatter

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