Chapter

Contemporary Human Impacts on Alpine Ecosystems: The Direct and Indirect Effects of Human-Induced Climate Change and Land Use

Authors:
To read the full-text of this research, you can request a copy directly from the author.

Abstract

Alpine ecosystems account for c. 3% of terrestrial habitats yet, along with adjacent mountain systems, provide water resources to nearly half of the world's human population. Approximately 20% of humans live in or near mountain areas, making it inherently important to understand contemporary impacts on these systems. Here, I review literature regarding contemporary and projected human impacts on alpine ecosystems, including the direct and indirect impacts of human-induced climate change on alpine plant, animal, and soil communities. I also discuss the influence of recreation and tourism, grazing, and other land use changes including the introduction of nonnative and invasive species in alpine systems. I conclude with management implications as well as future areas of research needed to better understand changes to these systems.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the author.

... Keywords: hydrology, critical zone, topography, random forest, Niwot Ridge LTER, Rocky Mountains, Colorado INTRODUCTION Alpine regions are essential sources of fresh water to lower elevation ecosystems and ∼50% of people around the globe (Winkler, 2019). In addition, they are also some of the most vulnerable to climate change (Buytaert et al., 2011;Seidl et al., 2011;Ernakovich et al., 2014). ...
... In addition, they are also some of the most vulnerable to climate change (Buytaert et al., 2011;Seidl et al., 2011;Ernakovich et al., 2014). Many researchers have shown that alpine areas are already warming and predict that they may experience the highest levels and impacts of warming well before other ecosystems (e.g., Bradley, 2004;Cannone et al., 2007;Pepin et al., 2015;Winkler, 2019). These impacts include changes to the timing, amount, and quality of water exported from alpine catchments (Barnett et al., 2005;Horton et al., 2006;Tague, 2009;Schneeberger et al., 2015), among others. ...
Article
Full-text available
Climate warming in alpine regions is changing patterns of water storage, a primary control on alpine plant ecology, biogeochemistry, and water supplies to lower elevations. There is an outstanding need to determine how the interacting drivers of precipitation and the critical zone (CZ) dictate the spatial pattern and time evolution of soil water storage. In this study, we developed an analytical framework that combines intensive hydrologic measurements and extensive remotely-sensed observations with statistical modeling to identify areas with similar temporal trends in soil water storage within, and predict their relationships across, a 0.26 km ² alpine catchment in the Colorado Rocky Mountains, U.S.A. Repeat measurements of soil moisture were used to drive an unsupervised clustering algorithm, which identified six unique groups of locations ranging from predominantly dry to persistently very wet within the catchment. We then explored relationships between these hydrologic groups and multiple CZ-related indices, including snow depth, plant productivity, macro- (10 ² ->10 ³ m) and microtopography (<10 ⁰ -10 ² m), and hydrological flow paths. Finally, we used a supervised machine learning random forest algorithm to map each of the six hydrologic groups across the catchment based on distributed CZ properties and evaluated their aggregate relationships at the catchment scale. Our analysis indicated that ~40–50% of the catchment is hydrologically connected to the stream channel, lending insight into the portions of the catchment that likely dominate stream water and solute fluxes. This research expands our understanding of patch-to-catchment-scale physical controls on hydrologic and biogeochemical processes, as well as their relationships across space and time, which will inform predictive models aimed at determining future changes to alpine ecosystems.
... The rising temperatures across the globe are caused by GHG of natural and anthropogenic origin, majority of which is atmospheric carbon dioxide (CO 2 ), indicated as showing a consistent, almost linear correlation between its cumulative emissions and projected global temperature. CO 2 concentration has surged by over 40% since the industrial revolution, and it is predicted to increase further up to 770 ppm in 2100 (compared to present concentration of around 400 ppm), while the level of 450 ppm of CO 2 [atm] has been suggested as a critical threshold which would cause an increase in the global mean temperature of 2 °C above preindustrial values (Ahanger et al. 2013;IPCC 2013;Mahato 2014;Pachauri et al. 2014;FAO and ITPS 2015;Lefevre et al. 2017;Challinor et al. 2018;Winkler 2019). The extent and intensity of climate-related factor changes (e.g., rising of atmospheric CO 2 level, atmospheric N deposition, elevated temperature, altered rainfall or moisture, pressure, light intensity) and the interactions among multifactorial stress combinations are predicted to increase in the next decades (IPCC 2013(IPCC , 2018Pachauri et al. 2014;Hoegh-Guldberg et al. 2018). ...
... The consequences of climate variability lead to the creation of environmental change conditions-frequent and extreme weather phenomena such as heat waves, drought, salinity, alkaline/acid soils, floods, sea level rise, and ocean acidification. They will cause direct/indirect and positive/negative effects on living organisms such as alterations in species composition and range; species invasions and extinctions; phenology, biodiversity, and ecosystem regime shifts; as well as the generation of new interactions in novel communities, novel intra-and interspecies interactions among plants and microbial communities, and changed feedback processes which may in turn affect species dynamics and interactions and can lead to altered ecological processes and ecosystem functions Classen et al. 2015;Ravichandran and Thangavelu 2017;Hassani et al. 2018;Hawkins and Crawford 2018;Hoegh-Guldberg et al. 2018;Winkler 2019). ...
Chapter
Under natural conditions, the defense responses of plants exposed to combined abiotic and biotic stress factors, which can randomly interact with each other, are in many aspects different from the response induced by an individual stress. Predicted climatic changes through affecting these simultaneously occurring interactions might change the microclimate surrounding plants, plants’ susceptibility, the range of host microorganisms (i.e., symbionts or pathogens), and their simultaneous interaction with plants. The influence of climate change on interactions between environmental stresses and plants can lead to positive or negative impacts of one stress on the others and cause changes in strategies adopted by plants—either negative (i.e., susceptibility) or positive (i.e., tolerance)—thus causing modifications of primary and secondary metabolism of plants. Primary metabolism plays a key role in plants’ adaptive/defense response through the influence on the modulation of secondary metabolism and the activation of the host’s various defense mechanisms. Alterations in primary and secondary metabolism might include changes in the availability of nutrients, metabolically active compounds, or in carbon (C) and nitrogen (N) metabolism and C/N balance.
... Currently, the species is well established and widely distributed in the Pyrenees, thanks to multiple introductions events and to the colonization of new territories by the population (Barrio et al., 2013;Ruys and Couzi, 2015). The presence of marmots in harsh mountainous environments (1060-2600 m a.s.l) makes this species particularly sensitive to the effects of climate change (Ruys and Couzi, 2015;Winkler, 2019). In a population in the Alps, studied for more than 23 years, complex changes in population social interactions and demography have been recorded (Bichet et al., 2016;Rézouki, 2018;Rézouki et al., 2016;Tafani et al., 2013). ...
Article
Full-text available
The Alpine marmot (Marmota marmota) is a social mammal living in mountainous grassland areas and has the particularity to hibernate in winter. Recent studies on a population in the French Alps found that climate change is affecting Alpine marmot population dynamics and might impact their overall distribution in the future. Using Species Distribution Models (SDMs), the effect of climate change on Alpine marmot's future distribution was investigated at a local scale, in the western part of the Pyrenean massif (New-Aquitaine region, France). This scale was chosen as an appropriate action scale for the conservation strategy for the species. Three climatic scenarios were used (RCP 2.6, RCP 4.5, and RCP 8.5) over three future 30-year periods (2021–2050, 2040–2070, 2071–2100) to predict the short- to long-term potential distribution of the target species. The results are consistent with naturalistic knowledge of the species´ ecological needs in terms of variable importance and response type. Mean maximum temperature in winter, standard-deviation of daily temperature in winter, along with the median rainfall amount in summer were the three most important climatic variables. Predictions under the two most pessimistic climate scenarios showed potential large habitat loss. In the long term, for RCP 4.5, an estimated habitat loss of 18% was predicted. In the case of RCP 8.5, a higher impact was predicted, with a 54% habitat loss. Our results show that high impact due to climate change can be expected at a long term. In addition, if winter climatic conditions are important for marmot survival through hibernation, drought in summer might be one of the drivers of future population dynamic and distribution. Our findings can be applied for other species living in grassland mountainous environments and for which access to food resources in summer is essential, facilitating the conservation of target areas.
... Dünya nüfusunun yaklaşık %10'u dağ ekosistemlerindeki kaynaklara bağlıdır. Çok daha büyük bir yüzdesi, özellikle su da dahil olmak üzere dağ ekosistemlerindeki diğer kaynaklardan yararlanmaktadır (Bundi 2010, Winkler 2019. ...
Article
Full-text available
1. Since alpine lakes are far from anthropogenic pressures, their natural structure is intact or slightly degraded. Due to its ecological structure, which is close to nature, such lakes are considered as "reference points". 2. The Giresun Mountains are considered to be among the "Important Natural Areas" because of the fact that they have alpine lakes with the glacial origin and high altitude (>2600 m). However, hydrobiological researches in these lakes are insufficient. 3. This research is the first hydrobiological research conducted in Karagöl Lake where one of the high mountain lakes in this area is. In high altitude lakes, algae growth season typically takes place between June and October before iciness. Therefore, Karagöl Lake was followed monthly for four months. In situ and laboratory water analyzes were performed and benthic and planktonic algae community was determined. 4. As a result of qualitative and quantitative analysis, Karagöl Lake has an algae community that is the majority of diatoms. Small benthic (Achnanthidium) and planktonic (Panctocsekiella) indicator diatoms are dominant. Biomass is low with diversity and wealth indexes. There is no risk of eutrophication according to chlorophyll-a value (mean chl-a <3.5 µg/L; maximum chl-a ≤8 µg/L). As a result of the water analysis, Karagöl Lake has first class water quality. Therefore, it has a "very good" water condition .
Book
Full-text available
La compréhension des effets locaux du changement climatique sur la biodiversité est essentielle pour orienter les politiques environnementales et de gestion des espaces naturels. L’échelle régionale se trouve à un niveau de décision politique pertinent pour la mise en place d’actions de lutte contre le changement climatique et pour la préservation de la biodiversité. Le manque de connaissances au niveau régional a conduit au développement d’un programme de recherche « les sentinelles du climat » en région Nouvelle-Aquitaine (au sud-ouest de la France). Ce programme a été développé selon une démarche innovante de recherche action en écologie du changement climatique et en biologie de la conservation suivant 3 étapes clés. La première étape appelée « Connaitre » est basée sur un réseau de suivi des effets sur la biodiversité locale à partir d’indicateurs. L’hypothèse de recherche est que les effets locaux peuvent être étudiés à partir d’indicateurs d’espèces de flore et de faune à capacité de déplacement limitée, appelées « sentinelles du climat ». Chaque indicateur est associé à un protocole de suivi scientifique standardisé à l’échelle locale. L’évolution des indicateurs est suivie pour chacun des écosystèmes et habitats étudiés suivants : 1) la flore : Communautés végétales des dunes littorales non boisées, des pelouses sèches calcicoles, des tourbières, landes tourbeuses et bas-marais acidiphiles, des lagunes du plateau landais, des rives d’étangs arrière-littoraux, de forêts à Hêtre de plaines; 2) les insectes : 1- les lépidoptères des pelouses sèches, de landes humides et des pelouses de montagne, avec deux études spécifiques pour les espèces Phengaris alcon et Parnassius apollo ; 2- les Leucorrhines et cortège d’odonates associé des lagunes des Landes de Gascogne ; 3- Gomphocerus sibiricus et le cortège des orthoptères associé des prairies et pelouses de montagne des Pyrénées-Atlantiques ; 3) les amphibiens : Hyla molleri des lagunes du triangle landais ; Hyla arborea des mares des landes et du bocage picto-limousin ; Rana pyrenaica des torrents de montagne ; 4) les reptiles : Timon lepidus des dunes grises du littoral aquitain ; Zootoca vivipara des landes humides et tourbières de Nouvelle-Aquitaine ; Iberolacerta bonnali et les lézards gris des affleurements et éboulis rocheux de montagne ; Vipera berus et les vipères des landes humides d’altitude ; 5) les mammifères : Marmota marmota des pelouses et rocailles pyrénéennes. La deuxième étape « Comprendre » est la phase d’analyses de données pour relier le changement climatique aux données biologiques de ces espèces sentinelles du climat selon trois échelles d’étude : 1) macro-écologique : les données régionales des observatoires régionaux permettent d’accéder aux données de présence des espèces qui sont mises en corrélation avec les données climatiques du présent et du futur pour créer des cartes de pertes et de gains potentiels ; 2) méso-écologique : sur des sites d’étude, la mise en œuvre de protocoles de dénombrements complète en données d’abondance et permet de suivre l’évolution des populations locales selon les variations climatiques sur le long terme ; 3) micro-écologique : les données de sondes biomimétiques et études en laboratoire permettent d’identifier finement la niche thermique et hydrique des espèces. Le changement climatique n’est pas le seul facteur. D’autres facteurs anthropiques sont également pris en compte via l’analyse du paysage selon des indices paysagers. Toutes ces données sont utilisées pour modéliser les réponses des espèces selon les différents scénarios climatiques du GIEC jusqu’en 2100. Cet ouvrage présente les résultats exploratoires développés durant ce programme de 2016 à 2021. En troisième étape « Agir », ces connaissances développées permettent de proposer une première réflexion d’actions pour protéger et prévenir l’extinction des espèces et promouvoir la conservation de la biodiversité à l’échelle régionale. L’objectif à terme est de développer un programme de surveillance décennal en Nouvelle-Aquitaine similaire à ce que font les climatologues utilisant des pas de temps de 30 ans. Ce programme pourrait servir de système d’alerte, prédisant quelles zones seront les plus à risque et quand elles le deviendront, ce qui pourrait aider à cibler les efforts de conservation et de gestion des espaces naturels.
Chapter
This review summarizes current understanding of drivers for change and of the impact of accelerating global changes on mountains, encompassing effects of climate change and globalization. Mountain regions with complex human–environment systems are known to exhibit a distinct vulnerability to the current fundamental shift in the Earth System driven by human activities. We examine indicators of the mountain cryosphere and hydrosphere, of mountain biodiversity, and of land use and land cover patterns, and show that mountain environments in the Anthropocene are changing on all continents at an unprecedented rate. Rates of climate warming in the world’s mountains substantially exceed the global mean, with dramatic effects on cryosphere, hydrosphere, and biosphere. Current climatic changes result in significantly declining snow-covered areas, widespread decreases in area, length, and volume of glaciers and related hydrological changes, and widespread permafrost degradation. Complex adaptations of mountain biota to novel constellations of bioclimatic and other site conditions are reflected in upslope migration and range shifts, treeline dynamics, invasion of non-native species, phenological shifts, and changes in primary production. Changes in mountain biodiversity are associated with modified structure, species composition, and functioning of alpine ecosystems, and compromise ecosystem services. Human systems have been negatively impacted by recent environmental changes, with both inhabitants of mountain regions as well as people living in surrounding lowlands being affected. Simultaneously, accelerating processes of economic globalization cause adaptation strategies in mountain communities as expressed clearly in changing land use systems and mobility patterns, and in increasing marginalization of peripheral mountains and highlands. The current state of the world’s mountains clearly indicates that global efforts to date have been insufficient to make significant progress towards implementing the Sustainable Development Goals of the 2030 Agenda for Sustainable Development, adopted by all United Nations member states.
Chapter
Full-text available
Mountain ecosystems provide water resources to nearly half of the world’s human population, with approximately 20% of humans living in or near mountain areas (Viviroli et al., 2011; Korner, 2009; Korner et al., 2017). As a result of their high biological diversity, uniquely adapted species, and the ease with which water and solid material can move through these systems, alpine habitats are hypothesized to be sensitive to perturbation and climate change (Nagy and Grabherr, 2009), potentially showing signs of change before other terrestrial ecosystems (Bowman, 2001). Furthermore, the importance of climatic factors over biotic ones in alpine areas suggests that the impacts of climate change on alpine plant communities may be more detectable than in lower elevation communities (Grabherr et al., 2000). Herein, we review the literature regarding expected climate changes in alpine ecosystems around the world and impacts on species, their distributions, and community assemblages. We also explore changes in biotic interactions, including plant-plant, plant-microbe, and plant-animal interactions. We briefly present experimental approaches used to study climate change in alpine systems and discuss the benefits and challenges of each.
Article
Full-text available
The spatial patterning of alpine plant communities is strongly influenced by the variation in physical factors such as temperature and moisture, which are strongly affected by snow depth and snowmelt patterns. Earlier snowmelt timing and greater soil-moisture limitations may favor wide-ranging species adapted to a broader set of ecohydrological conditions than alpine-restricted species. We asked how plant community composition, phenology, plant water relations, and photosynthetic gas exchange of alpine-restricted and wide-ranging species differ in their responses to a ca. 40-day snowmelt gradient in the Colorado Rocky Mountains (Lewisia pygmaea, Sibbaldia procumbens, and Hymenoxys grandiflora were alpine-restricted and Artemisia scopulorum, Carex rupestris, and Geum rossii were wide-ranging species). As hypothesized, species richness and foliar cover increased with earlier snowmelt, due to a greater abundance of wide-ranging species present in earlier melting plots. Flowering initiation occurred earlier with earlier snowmelt for 12 out of 19 species analyzed, while flowering duration was shortened with later snowmelt for six species (all but one were wide-ranging species). We observed >50% declines in net photosynthesis from July to September as soil moisture and plant water potentials declined. Early-season stomatal conductance was higher in wide-ranging species, indicating a more competitive strategy for water acquisition when soil moisture is high. Even so, there were no associated differences in photosynthesis or transpiration, suggesting no strong differences between these groups in physiology. Our findings reveal that plant species with different ranges (alpine-restricted vs. wide-ranging) could have differential phenological and physiological responses to snowmelt timing and associated soil moisture dry-down, and that alpine-restricted species' performance is more sensitive to snowmelt. As a result, alpine-restricted species may serve as better indicator species than their wide-ranging heterospecifics. Overall, alpine community composition and peak % cover are Frontiers in Plant Science | www.frontiersin.org 1 July 2018 | Volume 9 | Article 1140 Winkler et al. Alpine Snowmelt Gradient strongly structured by spatio-temporal patterns in snowmelt timing. Thus, near-term, community-wide changes (or variation) in phenology and physiology in response to shifts in snowmelt timing or rates of soil dry down are likely to be contingent on the legacy of past climate on community structure.
Article
Full-text available
Dwarf bamboos are evergreen woody grasses that produce large clonal patches and dominate the understories of the montane to subalpine zones of northern Japan. Recently, dwarf bamboos have expanded their distribution to above the treeline and into alpine meadows. To clarify the mechanism of rapid invasion into the alpine, we compared the morphological performance, biomass allocation, photosynthetic activity, CO 2 fixation ability, and sensitivity to temperature of dwarf bamboos in their native montane and expanding alpine sites in the Taisetsu Mountains. Alpine bamboo produced shorter but denser aboveground structures, where leaves were smaller and branching was more frequent. The total biomass of alpine bamboo was nearly half of that produced by montane bamboo. Montane bamboo produced more stems, while alpine bamboo invested more carbon in belowground structures. CO 2 fixation per land area by alpine bamboo was 1.3 times higher than rates observed in montane bamboo. Optimal temperatures for photo-synthesis were lower in alpine bamboo (15-20°C) than in montane bamboo (20-25°C), probably because of the rapid decrease in stomatal conductance at higher temperatures (>20°C) observed in the alpine site. Overall, leaf transpiration rates were higher in alpine bamboo, but water-use efficiency was similar between sites. A high flexibility in both morphological and physiological characteristics enabled dwarf bamboos to expand into alpine environments in response to recent climate change. ARTICLE HISTORY
Chapter
Full-text available
Climate warming has been more pronounced in Arctic and alpine areas, and changes in the mountain flora can be expected as the temperature envelope moves upslope. On the one hand, alpine habitats will shrink due to upward migration of species from lower areas, such as trees and tall plants. On the other hand, extinctions of summit plants may be slowed down considerably by the high diversity of microhabitats, the longevity of alpine plants and positive plant–plant interactions in extreme environments. This review chapter attempts to document and monitor vegetation changes on mountain summits. Vegetation surveys that repeat century-old historical vegetation records show considerable upward migration and subsequent increases in species on summits. This trend apparently has accelerated in recent decades. Detailed monitoring of the last decade in European mountain ranges, however, shows that this vegetation change may be at the cost of rare endemic species and alpine specialists in drier Mediterranean regions. This chapter furthermore reviews other factors than temperature influencing alpine vegetation, namely precipitation and snow, nutrients, atmospheric CO2 concentrations and land use. A subsequent question is how threatened mountain flora is by the ongoing environmental changes. Finally, this chapter discusses options for conservation and land use in high-alpine areas.
Article
Full-text available
Climate warming can lead to changes in alpine plant species interactions through modifications in environmental conditions, which may ultimately cause drastic changes in plant communities. We explored the effects of 4 years of experimental warming with open-top chambers (OTC) on Vaccinium myrtillus performance and its interaction with neighbouring shrubs at the Pyrenean treeline ecotone. We examined the effects of warming on height, above-ground (AG) and below-ground (BG) biomass and the C and N concentration and isotope composition of V. myrtillus growing in pure stands or in stands mixed with Vaccinium uliginosum or Rhododendron ferrugineum. We also analysed variations in soil N concentrations, rhizosphere C/N ratios and the functional diversity of the microbial community, and evaluated whether warming altered the biomass, C and N concentration and isotope composition of V. uliginosum in mixed plots. Our results showed that warming induced positive changes in the AG growth of V. myrtillus but not BG, while V. uliginosum did not respond to warming. Vaccinium myrtillus performance did not differ between stand types under increased temperatures, suggesting that warming did not induce shifts in the interaction between V. myrtillus and its neighbouring species. These findings contrast with previous studies in which species interactions changed when temperature was modified. Our results show that species interactions can be less responsive to warming in natural plant communities than in removal experiments, highlighting the need for studies involving the natural assembly of plant species and communities when exploring the effect of environmental changes on plant-plant interactions.
Article
Full-text available
Alpine zones are threatened globally by invasive species, hunting, and habitat loss caused by fire, anthropogenic development and climate change. These global threats are pertinent in New Zealand, with the least understood pressure being the potential impacts of introduced mammalian predators, the focus of this review. In New Zealand, alpine zones include an extensive suite of cold climate ecosystems covering c. 11% of the land mass. They support rich communities of indigenous invertebrates, lizards, fish, and birds. Many taxa are obligate alpine dwellers, though there is uncertainty about the extent to which distributions of some species are relicts of wider historical ranges. The impacts of introduced mammalian predators are well described in many New Zealand ecosystems, though little is known about the impacts of these predators on alpine fauna. Here we review the importance of alpine habitats for indigenous fauna and the impacts of introduced mammalian predators; and develop a conceptual model explaining threat interactions. Most evidence for predation is anecdotal or comes from studies of species with wider ranges and at lower altitudes. Nevertheless, at least ten introduced predator species have been confirmed as frequent predators of native alpine species, particularly among birds and invertebrates. In the case of the endangered takahe (Porphyrio hochstetteri) and rock wren (Xenicus gilviventris), stoats (Mustela erminea) are primary predators, which are likely to be impacting significantly on population viability. We also document records of mammalian predation on alpine lizards and freshwater fish. While the precise impacts on the long-term viability of threatened species have not been evaluated, anecdotal evidence suggests that predation by mammals is a serious threat, warranting predator control. Future research should focus on predicting when and where mammalian predators impact on populations of indigenous fauna, furthering our understanding of the alpine predator guild particularly through adaptive management experiments, and exploring interactions with other threats. http://newzealandecology.org/nzje/3300.
Article
Full-text available
Nitrogen (N) availability is projected to increase in a warming climate. But whether the more available N is immobilized by microbes (thus stimulates soil carbon (C) decomposition), or is absorbed by plants (thus intensifies C uptake) remains unknown in the alpine meadow ecosystem. Infrared heaters were used to simulate climate warming with a paired experimental design. Soil ammonification, nitrification, and net mineralization were obtained by in situ incubation in a permafrost region of the Qinghai-Tibet Plateau (QTP). Available N significantly increased due to the stimulation of net nitrification and mineralization in 0–30 cm soil layer. Microbes immobilized N in the end of growing season in both warming and control plots. The magnitude of immobilized N was lower in the warming plots. The root N concentration significantly reduced, but root N pool intensified due to the significant increase in root biomass in the warming treatment. Our results suggest that a warming-induced increase in biomass is the major N sink and will continue to stimulate plant growth until plant N saturation, which could sustain the positive warming effect on ecosystem productivity.
Article
Full-text available
Global warming is expected to significantly affect the runoff regime of mountainous catchments. Simple methods for calculating future glacier change in hydrological models are required in order to reliably assess economic impacts of changes in the water cycle over the next decades. Models for temporal and spatial glacier evolution need to describe the climate forcing acting on the glacier, and ice flow dynamics. Flow models, however, demand considerable computational resources and field data input and are moreover not applicable on the regional scale. Here, we propose a simple parameterization for calculating the change in glacier surface elevation and area, which is mass conserving and suited for hydrological modelling. The Δ h -parameterization is an empirical glacier-specific function derived from observations in the past that can easily be applied to large samples of glaciers. We compare the Δ h -parameterization to results of a 3-D finite-element ice flow model. As case studies, the evolution of two Alpine glaciers of different size over the period 2008–2100 is investigated using regional climate scenarios. The parameterization closely reproduces the distributed ice thickness change, as well as glacier area and length predicted by the ice flow model. This indicates that for the purpose of transient runoff forecasts, future glacier geometry change can be approximated using a simple parameterization instead of complex ice flow modelling. Furthermore, we analyse alpine glacier response to 21st century climate change and consequent shifts in the runoff regime of a highly glacierized catchment using the proposed methods.
Article
Full-text available
How species invasions impact ecosystem structure and function at important ecotones or boundaries is unknown, but may provide insight into the impacts of climate change and the mechanisms underlying community change. The dwarf bamboo, Sasa kurilensis, may be a good system to understand these issues, as the species impacts ecosystem features as it encroaches beyond treeline into alpine systems. We used remote sensing imagery spanning a 35 year period to quantify S. kurilensis expansion patterns across its range, measured growth and stress tolerances of S. kurilensis above and below treeline, and evaluated components of growth to reveal how shifts in light and water limitations influence the ontogeny of height, branching, and leaf production. We show that S. kurilensis more than doubled its abundance across its range, but more than tripled its abundance near and above treeline. Soil dry-down rates were a key driver of invasion above and below treeline, where growth rates decreased with more rapid rates of soil moisture dry-down. We found S. kurilensis responds to competition and climate stress by increasing allocation to belowground structures at high elevations. Further, it invests more carbon in fewer—yet taller and heavier—aboveground structures in low-light, low elevation environments. It appears this species’ success is driven by considerable morphological and physiological flexibility, coupled with changes in water balance associated with snowmelt that in each habitat results in sites increasingly hospitable to bamboo. Overall, this study links resource allocation strategies and physiological responses to climate change and provides a mechanistic explanation of invasion success.
Article
Full-text available
Climate change is expected to alter primary production and community composition in alpine ecosystems, but the direction and magnitude of change is debated. Warmer, wetter growing seasons may increase productivity; however, in the absence of additional precipitation, increased temperatures may decrease soil moisture, thereby diminishing any positive effect of warming. Since plant species show individual responses to environmental change, responses may depend on community composition and vary across life form or functional groups. We warmed an alpine plant community at Niwot Ridge, Colorado continuously for four years to test whether warming increases or decreases productivity of life form groups and the whole community. We provided supplemental water to a subset of plots to alleviate the drying effect of warming. We measured annual above-ground productivity and soil temperature and moisture, from which we calculated soil degree days and adequate soil moisture days. Using an information-theoretic approach, we observed that positive productivity responses to warming at the community level occur only when warming is combined with supplemental watering; otherwise we observed decreased productivity. Watering also increased community productivity in the absence of warming. Forbs accounted for the majority of the productivity at the site and drove the contingent community response to warming, while cushions drove the generally positive response to watering and graminoids muted the community response. Warming advanced snowmelt and increased soil degree days, while watering increased adequate soil moisture days. Heated and watered plots had more adequate soil moisture days than heated plots. Overall, measured changes in soil temperature and moisture in response to treatments were consistent with expected productivity responses. We found that available soil moisture largely determines the responses of this forb-dominated alpine community to simulated climate warming.
Article
Full-text available
Freezing temperatures and summer droughts shape plant life in Mediterranean high-elevation habitats. Thus, the impacts of climate change on plant survival for these species could be quite different to those from mesic mountains. We exposed 12 alpine species to experimental irrigation and warming in the Central Chilean Andes to assess whether irrigation decreases freezing resistance, irrigation influences freezing resistance when plants are exposed to warming, and to assess the relative importance of irrigation and temperature in controlling plant freezing resistance. Freezing resistance was determined as the freezing temperature that produced 50 % photoinactivation [lethal temperature (LT50)] and the freezing point (FP). In seven out of 12 high-Andean species, LT50 of drought-exposed plants was on average 3.5 K lower than that of irrigated plants. In contrast, most species did not show differences in FP. Warming changed the effect of irrigation on LT50. Depending on species, warming was found to have (1) no effect, (2) to increase, or (3) to decrease the irrigation effect on LT50. However, the effect size of irrigation on LT50 was greater than that of warming for almost all species. The effect of irrigation on FP was slightly changed by warming and was sometimes in disagreement with LT50 responses. Our data show that drought increases the freezing resistance of high-Andean plant species as a general plant response. Although freezing resistance increases depended on species-specific traits, our results show that warmer and moister growing seasons due to climate change will seriously threaten plant survival and persistence of these and other alpine species in dry mountains.
Article
Full-text available
It is necessary to look at the big picture when managing biological resources on the Qinghai-Xizang (Tibetan) plateau. Plateau pikas (Ochotona curzoniae) are poisoned widely across the plateau. Putative reasons for these control measures are that pika populations may reach high densities and correspondingly reduce forage for domestic livestock (yak, sheep, horses), and because they may be responsible for habitat degradation. In contrast, we highlight the important role the plateau pika plays as a keystone species in the Tibetan plateau ecosystem. The plateau pika is a keystone species because it: (i) makes burrows that are the primary homes to a wide variety of small birds and lizards; (ii) creates microhabitat disturbance that results in an increase in plant species richness; (iii) serves as the principal prey for nearly all of the plateau's predator species; (iv) contributes positively to ecosystem-level dynamics. The plateau pika should be managed in concert with other uses of the land to ensure preservation of China's native biodiversity, as well as long-term sustainable use of the pastureland by domestic livestock.
Article
Full-text available
Analyses of multispectral satellite data indicate accelerated glacier decline around the globe since the 1980s. By using digitized glacier outlines inferred from the 1973 inventory and Landsat Thematic Mapper (TM) satellite data from 1985 to 1999, we obtained area changes of about 930 Alpine glaciers. The 18% area reduction as observed for the period 1985 to 1999 (−1.3% a⁻¹) corresponds to a seven times higher loss rate compared to the 1850–1973 decadal mean. Extrapolation of area change rates and cumulative mass balances to all Alpine glaciers yields a corresponding volume loss of about 25 km³ since 1973. Highly individual and non-uniform changes in glacier geometry (disintegration) indicate a massive down-wasting rather than a dynamic response to a changed climate. Our results imply stronger ongoing glacier retreat than assumed so far and a probable further enhancement of glacier disintegration by positive feedbacks.
Article
Full-text available
Climate change in the European Alps during the 20th century has been characterized by increases in minimum temperatures of about 2°C, a more modest increase in maximum temperatures, little trend in precipitation data, and a general decrease of sunshine duration through to the mid-1980s. Temperature increase has been most intense in the 1940s, followed by the 1980s. The warming experienced since the early 1980s, while synchronous with the global warming, is of far greater amplitude and reaches close to 1°C for this ensemble average and up to 2°C for individual sites. Such changes caused pronounced effects in the glacial and periglacial belts. Since the middle of the past century - the end of the Little Ice Age - the glacierization of the European Alps has lost about 30 to 40% in surface area and around half its original volume. The estimated total glacier volume in the European Alps was some 130 km3 for the mid-1970s, but strongly negative mass balances have caused an additional loss of about 10 to 20% of this remaining ice volume since 1980. Periglacial permafrost in the Alps today occupies an area comparable to the glacierized area and must have been affected as well, but its secular evolution is much less well known. Simulations of high-resolution climatologies for double-CO2 situations using regional climate models (RCM) with a 20-km horizontal grid give generally higher winter temperatures, a more marked increase in summer temperatures, indications that temperature increases more at higher elevations than at lower altitudes, and higher/more intense precipitation in winter, but much dryer conditions in summer. Under such conditions, the Alps would lose major parts of their glacier cover within decades, warming of cold firn areas at high altitudes could become pronounced and lower limits of permafrost occurrence in the Alps could rise by several hundred meters. Pronounced disequilibria could result, in the water cycle, in mass wasting processes, and in sediment flux as well as in growth conditions of vegetation. For those directly involved with such changes, the main challenge would be to adapt to high and accelerating rates of environment evolution. Empirical knowledge would have to be replaced increasingly by improved process understanding, especially concerning runoff formation and slope stability. In view of the uncertainties involved with future projections, highest priority should be given to appropriate monitoring programs.
Article
Full-text available
Weather conditions may affect the quality of an outdoor recreation experience. Quality of the recreation may be reflected in the visitor's willingness to pay or their net economic benefits of recreation. We used the contingent valuation method to measure the effects of weather on net willingness to pay (WTP) for trips to Rocky Mountain National Park in Colorado. We used a visitor survey to elicit responses to a dichotomous-choice WTP question and to gather information about recreation activities. Results were analyzed with daily weather data to test for climate effects on recreation benefits. We found that temperature and precipitation were statistically-significant determinants of WTP. We estimated increases in recreation benefits of 4.9% and 6.7% for two climate change scenarios.
Article
Full-text available
Despite their small extent, alpine ecosystems belong to the most valuable, yet highly threatened natural biotopes worldwide. Alpine habitats are endangered particularly by anthropogenic influences and climate change as well as invasions of non-native plants. Although plant invasions are regarded as one of the most serious threats to biodiversity globally, the knowledge of their impact on the arthropod assemblages of alpine environments is virtually absent. Therefore, we studied the effects of the non-native dwarf pine Pinus mugo on a model group of carabid beetles in the alpine zone of the Hrubý Jeseník Mts., Czech Republic. We evaluated the effects of age, cover and distance from dwarf pine stands on the community structure and the functional diversity of the Carabidae. The majority of the species significantly declined in abundance with increasing age and cover of dwarf pine stands. Species surviving there were typically food generalists associated with the forest environment. In contrast, carabids with high conservation value bound to open habitats (e.g., Amara erratica and Carabus sylvestris) decreased in dwarf pine areas as well as food specialists (e.g., Cychrus caraboides) and large forest species in the genus Carabus. The decline in abundance of carnivorous species may be a consequence of the similar decline in herbivores dependent on the native vegetation. Concurring with this interpretation, abundance of many herbivorous species (e.g. Amara spp.) decreased within pine stands. The negative effect of dwarf pine stands on the community structure of montane carabids was also apparent in changes of functional diversity. Age and cover of dwarf pine significantly decreased functional richness and divergence of carabid trophic groups. Considering the small area of alpine tundra in the Central European mountain ranges, the expansive dwarf pine represents a serious threat to this unique montane biodiversity. Therefore we recommend the immediate reduction or removal of non-native dwarf pine stands.
Article
Full-text available
Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment. The Earth's ecosystems are under ever-increasing pressure of global change due to anthropogenic activities. In addition to the direct pressure of land use change where natural ecosystems are altered by human activities (e.g. farming, clear cutting and the spread of human infrastructure), indirect pressure is growing due to increased deposits of nutrients 1,2
Article
Full-text available
Because of the contrastive differences in environment and species composition climatic amelioration may affect alpine vegetation differently between fellfield and snowbed communities To test this prediction, the effects of warming on plant growth and vegetation structure were studied in two fellfield and two snowbed communities in northern Japan over 7 years using open-top-chambers (OTCs) OTCs increased the temperature by 1 1-1 8 degrees C, but the effects on snowmelt time and soil moisture were small Vegetation height and canopy volume increased substantially at both fellfield sites as a result of the use of OTCs Deciduous shrubs increased substantially at the lower fellfield and grammoids increased at the upper fellfield In contrast, the responses of snowbed plants to OTCs were not significant Because snowbed plants are snow covered until mid-summer, climatic amelioration during the snow-free period may influence plant growth only slightly if the snow-free period does not change Species richness and diversity were not changed by OTCs at any of the sites, indicating that the effect of warming alone may not be strong enough to change the species composition and diversity over several years These results indicate significant variation in the response among alpine communities to warming
Article
Full-text available
Elevated global temperatures are expected to alter vegetation dynamics by interacting with physiological processes, biotic relationships and disturbance regimes. However, few studies have explicitly modeled the effects of these interactions on rates of vegetation change, despite such information being critical to forecasting temporal patterns in vegetation dynamics. In this study, we build and parameterize rate-change models for three dominant alpine life forms using data from a 7-year warming experiment. These models allowed us to examine how the interactions between experimental warming, the abundance of bare ground (a measure of past disturbance) and neighboring life forms (a measure of life form interaction) affect rates of cover change in alpine shrubs, graminoids and forbs. We show that experimental warming altered rates of life form cover change by reducing the negative effects of neighboring life forms and positive effects of bare ground. Furthermore, we show that our models can predict the observed direction and rate of life form cover change at burned and unburned long-term monitoring sites. Model simulations revealed that warming in unburned vegetation is expected to result in increased forb and shrub cover and decreased graminoid cover. In contrast, in burned vegetation, warming is predicted to slow post-fire regeneration in both graminoids and forbs and facilitate rapid expansion in shrub cover. These findings illustrate the applicability of modeling rates of vegetation change using experimental data. Our results also highlight the need to account for both disturbance and the abundance of other life forms when examining and forecasting vegetation dynamics under climatic change.
Article
Full-text available
Treeline advance is reported as a widespread response to rising temperatures, yet few studies have considered the impact of treeline advance on the diversity and function of high altitude systems. Evidence suggests that climate change is already having a negative impact on alpine diversity and is modifying functions such as carbon sequestration and nutrient cycling. Treeline advance is likely to further affect diversity and function, yet our understanding of the processes involved is limited. Here we review and synthesize literature that assesses the impact of treeline advance into treeless ecosystems. Using published literature, we explore to what extent treeline advance will lead to the displacement of alpine species and the fragmentation of alpine habitats. While large changes will be observed in the ecosystems above the current treeline as trees migrate, it is likely that these newly forested areas will deviate substantially from the established forests from which they have developed. Consequently, at the forest community level we investigate the potential for differential response speeds of typical forest plant species, and the potential for treeline advance to lead to community disassembly. Given that changes in species presence and abundance can alter the functional composition of plant communities, we explore the potential for shifts in tree distribution to lead to changes in carbon storage, nutrient cycling, and hydrological properties of ecosystems. Despite typically being intensively studied regions, the likely impact of forest expansion above the current mountain treeline has received relatively little attention and so we identify key knowledge gaps that should act as priorities for future research in mountain systems.
Article
Full-text available
In snowbed habitats, characterized by a long-lasting snow cover, the timing of snowmelt can be included among the major factors controlling plant phenology. Nevertheless, only a few ecological studies have tested the responses of flowering phenology of species growing in very late snow-free habitats to an advanced snowmelt (AS) date. The aim of this study was to determine the impacts of an extremely earlier melt-out of snow on flowering phenology of vascular plant species inhabiting an alpine snowbed. The study was conducted in the high Gavia Valley (Italy, 2,700 m a.s.l.). On 30th May 2012, we removed manually the snow cover and set up an experiment with 5 AS and 5 control plots. Phenological observations of the most abundant vascular species were conducted every 4–6 days. Moreover, we calculated cumulative soil temperature and recorded the mortality of reproductive structures of three species. For several species flowering occurred earlier, and the prefloration period was extended in the AS treatment in comparison with the control. For the majority of species, cumulative soil temperatures in the AS treatment and the control were comparable, confirming that temperature exerts the main control on the flowering of the species inhabiting snowbeds. Earlier flowering species resulted more affected by an AS date in comparison with later flowering species. The mortality of reproductive structures did not increase in the AS treatments in comparison with the control suggesting that few and weak frost events in late spring do not affect the survival of reproductive structures of the species studied.
Article
Full-text available
Land abandonment exacerbated by climate change has led to increased woody plant encroachment of mountain grasslands in many regions of the world. The present study assessed woody plant encroachment below 2100 m a.s.l. (the potential tree line) in the Central Pyrenees of Spain and the association of this encroachment with changes in land use. Remote sensing data from Landsat-5 Thematic Mapper (TM) from the mid-1980s and mid-2000s were analyzed by supervised classification for identification of land cover types. The transition matrix indicated that shrublands were the most dynamic plant communities. Consequently, 21% of cultivated areas, 19% of dense grasslands, and 24% of sparse grasslands became shrublands during the period analyzed, and 35% of shrublands became forest. Generalized Additive Mixed Models (GAMM) was used to identify biophysical and anthropogenic factors that were significantly correlated with woody plant encroachment of dense and sparse grasslands. Distance to the nearest woody plant habitat (shrub or forest) was the most strongly correlated factor with woody plant encroachment of both types of grasslands. This factor explained 69% and 71% of the variance in models of dense and sparse grasslands, respectively. Besides this factor, anthropogenic factors had larger effects on woody plant encroachment of dense grasslands, regions that were more productive and accessible. However, biophysical and especially topographic factors had slightly greater effects on woody plant encroachment of sparse grasslands, regions that were less productive and accessible. The changes in land cover that we observed indicated that land cover has become more homogeneous. There have been reductions in the variety, functions, and services of the plant communities, particularly in areas below the potential tree line that are vulnerable to the development of woody plant habitats.
Data
Full-text available
Within alpine environments the interactions of air temperature, solar irradiance, wind, surface albedo, microtopography, and biotic traits all influence patterns of soil and plant canopy temperatures. The resulting mosaic of surface temperatures has a profound impact on ecosystem processes, plant survival, and ecophysiological performance. Previous studies have documented large and persistent variations in microhabitat temperatures over mesoscale alpine terrains. We have used a novel mobile system to examine changes in soil and plant canopy surface temperatures at spatial scales of centimeters and temporal scales of minutes in an alpine fellfield habitat in the White Mountains of California. In the middle of a summer day, the mean surface temperature differences between points 2, 5, and 10 cm apart were 2.9, 5.4, and 9.0 degrees C, respectively, and extreme differences of 18 degrees C or more were found over distances of a few centimeters. These thermal patterns are due not only to substrate material but also to biotic conditions of plant canopy architecture and ecophysiological traits of individual species. The magnitude of temperature variation at these fine scales is greater than the range of warming scenarios in Intergovernmental Panel on Climate Change (IPCC) projections, suggesting that these habitats offer the capacity of significant thermal heterogeneity for plant survival.
Article
Full-text available
Flowering is a critical stage in plant life cycles, and changes in phenology might alter processes at the species, community and ecosystem levels. Therefore, likely flowering-time responses to global-change drivers are needed for predictions of global-change impacts on natural and managed ecosystems. Predicting responses of species to global changes would be simplified if functional, phylogenetic or biogeographical traits contributed substantially to a species’ response. Here we investigate the role of growth form (grass, graminoid, forb, subshrub), longevity (annual, perennial), origin (native, exotic) and flowering time in determining the impact of elevated [CO2] (550 μmol mol-1) and infrared warming (mean warming of +2°C) on flowering times of 31 co-occurring species of a range of species-types in a temperate grassland in 2004, 2005 and 2007. Warming reduced time to first flowering by an average of 20.3 days in 2004, 2.1 days in 2005 and 7.6 days in 2007; however, the response varied among species and was unrelated to growth form, origin or longevity. Elevated [CO2] did not alter flowering times; neither was there any [CO2] by species-type interaction. However, both warming and elevated [CO2] tended to have a greater effect on later-flowering species, with time to first flowering of later-flowering species being reduced by both elevated [CO2] (P < 0.001) and warming (P < 0.001) to a greater extent than that of earlier-flowering species. These results have ramifications for our predictions of community and ecosystem interactions in native grasslands in response to global change.
Article
Full-text available
Increasing documentation of changes in the distribution of species provides evidence of climate change impacts, yet surprisingly little empirical work has endeavoured to quantify how such recent and rapid changes impact genetic diversity. Here we compare modern and historical specimens spanning a century to quantify the population genetic effects of a climate-driven elevational range contraction in the alpine chipmunk, Tamias alpinus, in Yosemite National Park, USA. Previous work showed that T. alpinus responded to warming in the park by retracting its lower elevational limit upslope by more than 500m, whereas the closely related chipmunk T. speciosus remained stable. Consistent with a reduced and more fragmented range, we found a decline in overall genetic diversity and increased genetic subdivision in T. alpinus. In contrast, there were no significant genetic changes in T. speciosus over the same time period. This study demonstrates genetic erosion accompanying a climate-induced range reduction and points to decreasing size and increasing fragmentation of montane populations as a result of global warming.
Article
Full-text available
Predicting climate change impact on ecosystem structure and services is one of the most important challenges in ecology. Until now, plant species response to climate change has been described at the level of fixed plant functional types, an approach limited by its inflexibility as there is much interspecific functional variation within plant functional types. Considering a plant species as a set of functional traits greatly increases our possibilities for analysis of ecosystem functioning and carbon and nutrient fluxes associated therewith. Moreover, recently assembled large-scale databases hold comprehensive per-species data on plant functional traits, allowing a detailed functional description of many plant communities on Earth. Here, we show that plant functional traits can be used as predictors of vegetation response to climate warming, accounting in our test ecosystem (the species-rich alpine belt of Caucasus mountains, Russia) for 59% of variability in the per-species abundance relation to temperature. In this mountain belt, traits that promote conservative leaf water economy (higher leaf mass per area, thicker leaves) and large investments in belowground reserves to support next year's shoot buds (root carbon content) were the best predictors of the species increase in abundance along with temperature increase. This finding demonstrates that plant functional traits constitute a highly useful concept for forecasting changes in plant communities, and their associated ecosystem services, in response to climate change.
Article
Full-text available
Fish introduction is a major threat to alpine lake biota leading to the loss of native species and to the degeneration of natural food-webs. This study provides an extensive investigation on the impact of the introduced fish Salvelinus fontinalis on the native communities of alpine lakes in the Gran Paradiso National Park. We compared the macroinvertebrate and zooplankton communities of six stocked and nine fishless lakes with a repeated sampling approach during the summers 2006–2009. The impact of fish presence on alpine lake fauna is often mediated by the strong seasonality governing these ecosystems, and it dramatically affects the faunal assemblage of littoral macroinvertebrates and the size, structure, and composition of the pelagic zooplankton community with a strong selective predation of the more visible taxa. Direct ecological impacts include a decrease or extinction of nonburrower macroinvertebrates and of large zooplankton species, while small zooplankton species and burrower macroinvertebrates were indirectly advantaged by fish presence. Due to the existence of a compensation between rotifers and crustaceans, fish presence does not affect total zooplankton biomass and diversity even if fish are a factor of ecological exclusion for large crustaceans. These compensatory mechanisms are a key process surrounding the impact of introduced fish in alpine lakes.
Article
Full-text available
We discuss a simplified mathematical model for alpine lake ecosystems, describing the summer (i.e. ice-free period) dynamics of phosphorus, phytoplankton, three zooplankton compartments and fish abundance. Model output is compared with measurements of total phosphorus, chlorophyll-a and zooplankton biomass recorded in twelve high-altitude mountain lakes in the Gran Paradiso National Park (northwestern Italy) during the summer season from 2006 to 2009. Model results are consistent with measured data, indicating the appropriateness of this modeling approach for quantitatively studying mountain lake ecosystems and their response to environmental changes. The comparison between the results obtained for lakes without fish and those where the allochthonous brook trout (Salvelinus fontinalis) was introduced clearly indicates the strong impact of fish stocking in alpine lakes.
Article
Full-text available
Short-term changes in plant species number, cover, frequency and composition were 22 studied along an altitudinal gradient crossing four Gloria summits (from 2240 m to 3024 23 m a.s.l.) from the treeline ecotone to the subnival zone in the Central Caucasus. Large-scale (summit area) and small-scale patterns (16 plots of 1m²/ summit) were monitored in 2001. Recording was repeated in 2008. During monitoring period average soil temperature and GDD (growing degree day) did not significantly increase. After seven years, a re-visitation of the summit area revealed a considerable increase of species richness especially at the lower alpine zone (CP1 and CP2 summit). At a small scale (1m²) species richness also increased at the lower summit (from 12.5 ± 2.87 to 15.5 ± 7 3.12 species on CP1 summit). The cover of 17 species significantly decreased, that of 5 increased. There were significant linear relationships between species richness and altitude and climatic variables. The main newcomers were species from the lower altitudinal zones and their percentage was highest on the southern slope. Endemics and cold-adapted species were not seriously endangered. In the Central Caucasus we do not consider the climate warming as the primary driver of the changes of plant richness and competition.
Article
Full-text available
High mountain ecosystems are vulnerable to the effects of climate warming and Australia's alpine vegetation has been identified as particularly vulnerable. Between 2004 and 2010, we monitored vegetation changes in a warming experiment within alpine open grassy-heathland on the Bogong High Plains, Victoria, Australia. The study was part of the International Tundra Experiment (ITEX Network) and used open-topped chambers (OTC) to raise ambient growing-season temperatures by ~1 C at two sites. We assessed the effects of experimental warming on vegetation composition, diversity and cover using ordination, linear models and hierarchical partitioning. Results were compared with vegetation changes at four long-term (non-ITEX) monitoring sites in similar vegetation sampled from 1979 to 2010. The warming experiment coincided with the driest 13-year period (1996–2009) since the late 1880s. At the ITEX sites, between 2004 and 2010, graminoid cover decreased by 25%, whereas forb and shrub cover increased by 9% and 20%, respectively. Mean canopy height increased from 7 cm to 10 cm and diversity increased as a result of changes in relative abundance, rather than an influx of new species. These vegetation changes were similar to those at the four non-ITEX sites for the same period and well within the range of changes observed over the 31-year sampling period. Changes at the non-ITEX sites were correlated with a decrease in annual precipitation, increase in mean minimum temperatures during spring and increase in mean maximum temperature during autumn. Vegetation changes induced by the warming experiment were small rather than transformational and broadly similar to changes at the long-term monitoring sites. This suggests that Australian alpine vegetation has a degree of resilience to climate change in the short to medium term (20–30 years). In the long term (>30 years), drought may be as important a determinant of environmental change in alpine vegetation as rising temperatures. Long-term vegetation and climate data are invaluable in interpreting results from short-term (10 years) experiments.
Article
Full-text available
This paper explores perceptions of ski-tourism representatives and other regional stakeholders about climate change impacts, limits to tourism development and adaptation strategies in the Australian Alps. This area faces rising temperatures, declining rain and snow falls, and shorter skiing seasons. Open-ended interviews examined the perceptions, plans and attitudes of the ski industry and those of conservation managers, local government officials and Australian researchers into tourism and/or climate change effects in the Australian Alps. All interviewees accepted climate change was a reality; several, however, questioned the worst-case scenarios. The major tourism-related adaptation strategies were snowmaking and diversifying to year-round tourism; the success of these strategies will vary according to individual resorts’ snowmaking capacity and potential summer tourism revenue. Currently non-snow-based tourism revenue is worth only approximately 30% of winter revenue. Social resistance to increased water and electricity use for snowmaking emerged as an important issue. Competition for water, including the needs of ecosystems, agriculture and fire protection in this summer-fire-prone region, and fire management issues, is a key concern. Current conflicts between the ski industry and other stakeholders over climate change adaptation call for a collaborative adaptation and change policy within the Australian Alps.
Article
Full-text available
Opportunities for observing long-term changes in natural biota are rare. Observations on the distribution and frequency of vascular plants were performed on 23 mountains situated along a west–east gradient in Jotunhei men, central Norway, where detailed site descriptions and species lists exist from ad 1930–31. The sites were resurveyed during the summer of 1998, to examine possible changes in species richness and species distributions along the altitudinal gradient during a 68-year period. Increased species richness was found on 19 of the mountains and was most pronounced at lower altitudes and in the eastern areas. Lowland species, dwarf shrubs and species with wide altitudinal and ecological ranges showed the greatest increases in abundance and altitudinal advances since the 1930–31 study. Species with more restricted habitat demands, such as some hygrophilous snow-bed species, have declined. High-altitude species have disappeared from their lower-elevation sites and increased their abundance at the highest altitudes. Climatic warming occurring in the last 100 years might have allowed the invasion of lowland and lee-slope species. Increased competition at sites where such species have invaded may have led to a decreased abundance of the less competitive species and a concentration of high-altitude species on the highest ridges. Natural succession since the ‘Little Ice Age’, increased deposition of nitrogen during recent years and changes in grazing and tourism might have in‘ uenced some of the species turnovers, but recent climatic changes are considered to be the most likely major driving factor for the changes observed.
Article
Full-text available
Trends in the timing of snowmelt and associated runoff in Colorado were evaluated for the 1978-2007 water years using the regional Kendall test (RKT) on daily snow-water equivalent (SWE) data from snowpack telemetry (SNOTEL) sites and daily streamflow data from headwater streams. The RKT is a robust, nonparametric test that provides an increased power of trend detection by grouping data from multiple sites within a given geographic region. The RKT analyses indicated strong, pervasive trends in snowmelt and streamflow timing, which have shifted toward earlier in the year by a median of 2-3 weeks over the 29-yr study period. In contrast, relatively few statistically significant trends were detected using simple linear regression. RKT analyses also indicated that November-May air temperatures increased by a median of 0.9°C decade-1, while 1 April SWE and maximum SWE declined by a median of 4.1 and 3.6 cm decade-1, respectively. Multiple linear regression models were created, using monthly air temperatures, snowfall, latitude, and elevation as explanatory variables to identify major controlling factors on snowmelt timing. The models accounted for 45% of the variance in snowmelt onset, and 78% of the variance in the snowmelt center of mass (when half the snowpack had melted). Variations in springtime air temperature and SWE explained most of the interannual variability in snowmelt timing. Regression coefficients for air temperature were negative, indicating that warm temperatures promote early melt. Regression coefficients for SWE, latitude, and elevation were positive, indicating that abundant snowfall tends to delay snowmelt, and snowmelt tends to occur later at northern latitudes and high elevations. Results from this study indicate that even the mountains of Colorado, with their high elevations and cold snowpacks, are experiencing substantial shifts in the timing of snowmelt and snowmelt runoff toward earlier in the year.
Article
Full-text available
A warming climate provides competitive advantages to Siberian pine (Pinus sibirica Du Tour) in areas with sufficient precipitation. The warmer temperatures observed in central Siberia over the past three decades appear to have had a noticeable effect on growth of Siberian pine and larch (Larix sibirica Ledeb.) in the south Siberian Mountain forest-tundra ecotone. Larch is more tolerant of harsh climates and exhibits an arboreal growth form, whereas Siberian pine is in krummholz form. Larch also has an advantage at the upper tree limit and in areas with low precipitation. Since the mid-1980s there have been measurable increases in growth increments, stand densification, regeneration propagation into the alpine tundra and transformation of krummholz into arboreal forms. Warming winter temperatures have been sufficient for increased survival of regeneration. Regeneration responded to temperature increase of 1°C by migration to areas 10-40 m higher in elevation. Regeneration has propagated into the alpine tundra at the rate of ~1.0-2.0 m year-1. Siberian pine and larch regeneration surpassed their upper historical limit by 10-80 m in elevation. While increased tree growth and migration into alpine tundra areas affect the regional carbon balance, it will also decrease albedo, which may increase warming at the regional level.
Article
Snow is one of the most important factors in the ecology of alpine ecosystems. In Australia, both the depth and duration of snow cover have declined significantly in recent decades and this trend is projected to continue with global warming. Many small arthropods remain active throughout the winter, within a space beneath the snowpack (subnivean) where the snow's insulation creates a thermally stable environment. Using field surveys and experimental manipulation of snow depth at two locations in the Australian alpine region, we explored the diversity of winter-active arthropods and their response to reduced snow. Individuals from 18 arthropod Orders were detected beneath the snow during winter, with Collembola, Araneae, Acari and Coleoptera accounting for 95–98% of the individuals collected. The subnivean taxa represented a distinct subset of those active outside the winter months. Removal of the snow layer increased daily temperature fluctuations, increased the number of days below freezing and raised the mean surface temperatures. Community composition was altered by snow removal, driven by changes in the numbers of two abundant springtail taxa at each location. We found a strong reduction in the abundances of both taxa at one study site, and contrasting responses (one strong positive and one strong negative) to snow removal at the second study site. Subnivean arthropod communities in Australia thus appear sensitive to snow conditions at small spatial scales.
Article
Although biotic responses to contemporary climate change are spatially pervasive and often reflect synergies between climate and other ecological disturbances, the relative importance of climatic factors versus habitat extent for species persistence remains poorly understood. To address this shortcoming, we performed surveys for American pikas (Ochotona princeps) at > 910 locations in 3 geographic regions of western North America during 2014 and 2015, complementing earlier modern (1994–2013) and historical (1898–1990) surveys. We sought to compare extirpation rates and the relative importance of climatic factors versus habitat area for pikas in a mainland-versus-islands framework. In each region, we found widespread evidence of distributional loss—local extirpations, upslope retractions, and encounter of only old sign. Locally comprehensive surveys suggest extirpation of O. princeps from 5 of 9 new sites from the hydrographic Great Basin and from 11 of 29 sites in northeastern California. Although American pikas were recorded as recently as 2011 in Zion National Park and in 2012 from Cedar Breaks National Monument in Utah, O. princeps now appears extirpated from all reported localities in both park units. Multiple logistic regressions for each region suggested that both temperature-related and water-balance-related variables estimated from DAYMET strongly explained pika persistence at sites in the Great Basin and in Utah but not in the Sierra-Cascade “mainland” portion of northeastern California. Conversely, talus-habitat area did not predict American pika persistence in the Great Basin or Utah but strongly predicted persistence in the Sierra-Cascade mainland. These results not only add new areas to our understanding of long-term trend of the American pika’s distribution, but also can inform decisions regarding allocation of conservation effort and management actions. Burgeoning research on species such as O. princeps has collectively demonstrated the heterogeneity and nuance with which climate can act on the distribution of mountain-dwelling mammals. Aunque las respuestas bióticas al cambio climático contemporáneo son espacialmente generalizadas y frecuentemente reflejan sinergias entre el clima y otros disturbios ecológicos, la importancia relativa de factores climáticos frente al área de hábitat para el mantenimiento de especies sigue siendo poco conocida. Para subsanar esta deficiencia, realizamos muestreos de la pika Americana (Ochotona princeps) en más de 910 sitios en 3 regiones geográficas del oeste de Norteamérica durante 2014 y 2015, complementando muestreos realizados en tiempos recientes (1994–2013) e históricos (1898–1990). Comparamos las tasas de extirpación para dilucidar la importancia relativa de los factores climáticos con respeto al área del hábitat disponible de las pikas bajo un marco conceptual de áreas continentales frente a zonas aisladas. En cada región, encontramos amplia evidencia en la pérdida de área de distribución - extinciones locales, desapariciones de las zonas bajas, y encuentro sólo de evidencia de ocupación pasada. Estudios localmente exhaustivos sugieren la extirpación de O. princeps en 5 de las 9 localidades nuevas muestreadas de la Gran Cuenca Hidrográfica (Great Basin), y en 11 de las 29 localidades en el noreste de California. Aunque las pikas todavía se encontraban en fechas recientes como en 2011 en el Parque Nacional Zion y en el Monumento Nacional Cedar Breaks en Utah en 2012, O. princeps ahora parece extirpada de todas las localidades donde fue encontrada anteriormente en ambos parques. Regresiones logísticas múltiples para cada región basados en factores ambientales como la temperatura y los factores relacionados con el balance del agua (ambos estimados por el DAYMET) explicaron claramente el patrón de persistencia de la pika en localidades de la Gran Cuenca y en Utah, pero no en el noreste de California, en el área “continental” de la montañas de Sierra Nevada y Cascades. Por el contrario, el hábitat de talud no predijo la persistencia de la pika en los sitios aislados en la Gran Cuenca y en Utah, pero lo predijo significativamente en el área continental (i.e., en las montañas de Sierra Nevada y Cascades). Estos resultados incrementan el conocimiento sobre la distribución histórica y la tendencia a largo plazo de la pika Americana. Este conocimiento también puede ayudar en la toma de decisiones sobre las prioridades en las acciones en conservación y manejo. El avance en conjunto en investigaciones de especies como O. princeps ha demostrado la heterogeneidad y la forma con que el clima actúa de diferente manera sobre la distribución de los mamíferos de montaña.
Article
How climate constrains species’ distributions through time and space is an important question in the context of conservation planning for climate change. Despite increasing awareness of the need to incorporate mechanism into species distribution models (SDMs), mechanistic modelling of endotherm distributions remains limited in the current literature. Using the American pika (Ochotona princeps) as an example, we present a framework whereby mechanism can be incorporated into endotherm SDMs. Pika distribution has repeatedly been found to be constrained by warm temperatures, so we used Niche Mapper, a mechanistic heat-balance model, to convert macroclimate data to pika-specific surface-activity time in summer across the western United States. We then explored the difference between using a macroclimate predictor (summer temperature) and using a mechanistic predictor (predicted surface-activity time) in SDMs. Both approaches accurately predicted pika presences in current and past climate regimes. However, the activity models predicted 8-19% less habitat loss in response to annual temperature increases of ~3-5°C predicted in the region by 2070, suggesting that pikas may be able to buffer some climate-change effects through behavioral thermoregulation that can be captured by mechanistic modeling. Incorporating mechanism added value to the modeling by providing increased confidence in areas where different modeling approaches agreed and providing a range of outcomes in areas of disagreement. It also provided a more proximate variable relating animal distribution to climate, allowing investigations into how unique habitat characteristics and intraspecific phenotypic variation may allow pikas to exist in areas outside those predicted by generic SDMs. Only a small number of easily obtainable data are required to parameterize this mechanistic model for any endotherm, and its use can improve SDM predictions by explicitly modeling a widely applicable direct physiological effect: climate-imposed restrictions on activity. This more complete understanding is necessary to inform climate-adaptation actions, management strategies, and conservation plans. This article is protected by copyright. All rights reserved.
Article
The New Guinea alpine-subalpine zone is the highest, largest, and wettest such region on any tropical island and it preserves great variations in biodiversity between the individual mountain areas. Relatively few plant species are confined to the alpine zone and this may reflect a limited time for adaptation by herbaceous species arriving in the formerly extensive alpine-subalpine biome. In the Pleistocene a zone above 3400 m was affected by glaciation while open subalpine habitat was greatly expanded by cooler climates and low levels of CO2 which hindered the formation of subalpine forest. With post-glacial warming, the subalpine contracted and open areas were invaded by shrublands and forest. Early to late Holocene opening out of the subalpine forest and shrublands is associated with fire that was a result of hunting by humans. This process starts early in some areas but is late or absent on more remote areas. The alpine is threatened by increased warming and potential invasion by emergent shrubs but is likely to prove resilient to extinction provided that wet conditions continue to prevail. Changing cultural use of high altitudes suggests that the subalpine shrublands are recovering in some areas. However, some mammals and bird species seem to have been lost or become restricted on mountains that are accessible from population centers at lower altitude. With few exceptions, management consists of benign neglect although widespread fires in 1997–1998 point to continuing human impacts linked to drought events. The large mine on Mount Jaya influences subalpine usage over a large area. Tourism is very minor and unlikely to expand while political problems affect both Papua New Guinea and Papua province and logistics remain a severe difficulty. However, locally managed tourism on Mount Wilhelm provides a good model for future development.
Article
1.Environmental change can affect species directly by altering their physical environment and indirectly by altering the abundance of interacting species. A key challenge at the interface of community ecology and conservation biology is to predict how direct and indirect effects combine to influence response in a changing environment. In particular, little is known about how direct and indirect effects on biodiversity develop over time or their potential to influence ecosystem function.2.We studied how nitrogen (N), winter precipitation (snow), and warming influenced diversity and ecosystem function over six years in alpine tundra. We used path analyses to partition direct effects of environmental manipulations from indirect effects due to changes in the abundance of two dominant plants. We hypothesize that 1) indirect effects will develop more slowly but will become stronger than direct effects over time, and 2) after six years, indirect effects will more strongly influence diversity while direct effects will influence ecosystem function.3.Indirect effects of N on diversity were consistently stronger than direct effects and actually developed quickly, prior to direct effects. Direct effects of snow on diversity were detected in year two but then subsequently were reversed, while indirect effects were detected in year four and grew stronger over time. Overall in year six, indirect effects were much stronger than direct effects.4.Direct effects predominated for three of four ecosystem functions we measured (productivity, N mineralization, winter N availability). The only indirect effects we found were that N and snow indirectly affected microbial biomass N by influencing Geum abundance. Across all four ecosystem measures, indirect effects were infrequent and weaker than direct effects.5.Synthesis. Increasing indirect effects on diversity over time indicate that short-term experiments or monitoring of natural systems may underestimate the full magnitude of global change effects on plant communities. Explicitly accounting for changes in dominant plant abundance may be necessary for forecasting plant community response to environmental change. Conversely, weak indirect effects for ecosystem processes suggest that predicting ecosystem function without knowledge of plant responses to global change may be possible.This article is protected by copyright. All rights reserved.
Article
Global climate change is already having significant impacts on arctic and alpine ecosystems, and ongoing increases in temperature and altered patterns of precipitation will affect the strong seasonal patterns that characterize these temperature-limited systems. The length of the potential growing season in these tundra environments is increasing due to warmer temperatures and earlier spring snowmelt. Here, we compare current and projected climate and ecological data from 20 Northern Hemisphere sites to identify how seasonal changes in the physical environment due to climate change will alter the seasonality of arctic and alpine ecosystems. We find that although arctic and alpine ecosystems appear similar under historical climate conditions, climate change will lead to divergent responses, particularly in the spring and fall shoulder seasons. As seasonality changes in the Arctic, plants will advance the timing of spring phenological events, which could increase plant nutrient uptake, production, and ecosystem C gain. In alpine regions, photoperiod will constrain spring plant phenology, limiting the extent to which the growing season can lengthen, especially if decreased water availability from earlier snowmelt and warmer summer temperatures leads to earlier senescence. The result could be a shorter growing season with decreased production and increased nutrient loss. These contrasting alpine and arctic ecosystem responses will have cascading effects on ecosystems, affecting community structure, biotic interactions and biogeochemistry. This article is protected by copyright. All rights reserved.
Article
In this paper we summarize recent research in geocryological studies carried out on the Qinghai-Tibet Plateau that show responses of permafrost to climate change and their environmental implications. Long-term temperature measurements indicate that the lower altitudinal limit of permafrost has moved up by 25 m in the north during the last 30 years and between 50 and 80 m in the south over the last 20 years. Furthermore, the thickness of the active layer has increased by 0.15 to 0.50 m and ground temperature at a depth of 6 m has risen by about 0.1° to 0.3°C between 1996 and 2001. Recent studies show that freeze-thaw cycles in the ground intensify the heat exchange between the atmosphere and the ground surface. The greater the moisture content in the soil, the greater is the influence of freeze-thaw cycling on heat exchange. The water and heat exchange between the atmosphere and the ground surface due to soil freezing and thawing has a significant influence on the climate in eastern Asia. A negative correlation exists between soil moisture and heat balance on the plateau and the amount of summer precipitation in most regions of China. A simple frozen soil parameterization scheme was developed to simulate the interaction between permafrost and climate change. This model, combined with the NCAR Community Climate Model 3.6, is suitable for the simulation of permafrost changes on the plateau. In addition, permafrost degradation is one of the main causes responsible for a dropping groundwater table at the source areas of the Yangtze River and Yellow River, which in turn results in lowering lake water levels, drying swamps and shrinking grasslands.
Article
1. Global warming is predicted to dramatically alter communities' composition through differ-ential colonization abilities, such as between sessile plants and their mobile herbivores. Novel interactions between previously non-overlapping species may, however, also be mediated by altered plants' responses to herbivore attack. 2. Syndromes of plant defences and tolerance are driven by inherited functional traits, biotic and abiotic conditions, and the geographical and historical contingencies affecting the commu-nity. Therefore, understanding climate change-driven herbivore responses and evolution towards a particular plant defence syndrome is key to forecasting species interactions in the near future. 3. In this paper, we first document variations in herbivory, and plant defences along altitudinal gradients that act as 'natural experiments'. We then use an empirical model to predict how specialist herbivore abundance may shift with respect to elevation in the near future. 4. Our field surveys and field experiment showed a decrease in herbivory with elevation. How-ever, contrary to expectations, our meta-regression analyses showed that plant defences, partic-ularly leaf toughness and flavonoid compounds, tend to be higher at high elevations, while secondary metabolites showed no clear trend with elevation. 5. Based on those results, we discuss how plant communities and species-specific plant defence syndromes will change in response to the climate-driven herbivore colonization of higher alti-tudes. Particularly, plant from high elevation, due to high protection against abiotic stress may be already ecologically fitted to resist the sudden increase in herbivory pressure that they will likely experience during global change.
Article
Impacts of introduced fish on zooplankton assemblages of lakes may persist for decades following fish removal. We tested this hypothesis by comparing zooplankton assemblages from four categories of lakes located in western Canadian mountain parks including lakes without and with fish that differed in their fish community complexity and fish-stocking history. Zooplankton species richness was greatest in lakes with a complex community of fish and least in pristine fishless lakes. Canonical correspondence analysis showed that taxonomic shifts in zooplankton assemblages could be attributed to differences in fish-stocking history between the study lakes. In fishless lakes, larger copepods (Eucyclops agilis, Diaptomus leptopus), cladocerans (Diaphanosoma, large Daphnia), and chaoborids were abundant, whereas in the presence of fish, small crustaceans were more common and chaoborids were relatively rare. Once introduced trout were absent from lakes, recovery trajectories for zooplankton showed a general taxonomic shift towards assemblages characteristic of fishless lakes that had never been fish stocked. Based on separation between previously stocked fishless lakes and naturally fishless mountain lakes in ordination space (chi-squared distance), taxonomic recovery by zooplankton assemblages from the influence of introduced salmonids may require an average of 19 years.
Article
Trout stocking in the mid-1960s eliminated the calanoid copepod Hesperodiaptomus arcticus and other large-bodied crustaceans such as Gammarus lacustris, Daphnia middendorffiana, and Daphnia pulex from many alpine lakes in the Rocky Mountain Parks of Canada. H. arcticus frequently dominates the plankton communities of fishless lakes, preying on rotifers and nauplius larvae. Following the extirpation of H. arcticus, rotifers and small-bodied cyclopoid copepods dominate the zooplankton assemblages of alpine lakes. We studied the zooplankton community of Snowflake Lake, Banff National Park, from 1966 to 1995. H. arcticus was eliminated following stocking of the lake with trout in the 1960s. It failed to become reestablished after the disappearance of the fish population in the mid-1980s. Several species of rotifers and small-bodied crustaceans, species originally rare or absent from the plankton, became abundant following fish stocking and remained so after the fish population declined. In 1992, we reintroduced H. arcticus to Snowflake Lake. The H. arcticus population grew exponentially for 4 yr, but had not reached stable densities typical of unmanipulated alpine lakes by 1995. By 1994, however, even the small population of Hesperodiaptomus was beginning to suppress populations of rotifers, copepod nauplii, and large diatoms. Because H. arcticus is omnivorous, a simple model of cascading trophic interactions did not predict the outcome of trophic manipulations in this alpine lake.