A 15,000 year record of vegetation and climate change from a treeline lake in the Rocky Mountains, Wyoming, USA

The Holocene ◽  
2011 ◽  
Vol 22 (7) ◽  
pp. 739-748 ◽  
Author(s):  
Scott Mensing ◽  
John Korfmacher ◽  
Thomas Minckley ◽  
Robert Musselman
Keyword(s):  
Climate Change ◽  
Rocky Mountains ◽  
Vegetation Change ◽  
Climatic Variability ◽  
High Elevation ◽  
Sagebrush Steppe ◽  
Climate Projections ◽  
Upward Movement ◽  
Regional Patterns ◽  
Vegetation And Climate

Future climate projections predict warming at high elevations that will impact treeline species, but complex topographic relief in mountains complicates ecologic response, and we have a limited number of long-term studies examining vegetation change related to climate. In this study, pollen and conifer stomata were analyzed from a 2.3 m sediment core extending to 15,330 cal. yr BP recovered from a treeline lake in the Rocky Mountains of Wyoming. Both pollen and stomata record a sequence of vegetation and climate change similar in most respects to other regional studies, with sagebrush steppe and lowered treeline during the Late Pleistocene, rapid upward movement of treeline beginning about 11,500 cal. yr BP, treeline above modern between ~9000 and 6000 cal. yr BP, and then moving downslope ~5000 cal. yr BP, reaching modern limits by ~3000 cal. yr BP. Between 6000 and 5000 cal. yr BP sediments become increasingly organic and sedimentation rates increase. We interpret this as evidence for lower lake levels during an extended dry period with warmer summer temperatures and treeline advance. The complex topography of the Rocky Mountains makes it challenging to identify regional patterns associated with short term climatic variability, but our results contribute to gaining a better understanding of past ecologic responses at high elevation sites.

scholarly journals Dendrochronological Assessment of Whitebark Pine Response to Past Climate Change: Implications for a Threatened Species in Grand Teton National Park

2014 ◽  
Vol 37 ◽  
pp. 58-64
Author(s):  
Kendra McLauchlan ◽  
Kyleen Kelly
Keyword(s):  
Climate Change ◽  
National Park ◽  
Fire History ◽  
Multiple Stressors ◽  
Fire Suppression ◽  
Climatic Variability ◽  
High Elevation ◽  
Whitebark Pine ◽  
Grand Teton National Park ◽  
Pine Trees

One of the keystone tree species in subalpine forests of the western United States – whitebark pine (Pinus albicaulis, hereafter whitebark pine) – is experiencing a significant mortality event (Millar et al. 2012). Whitebark pine occupies a relatively restricted range in the high-elevation ecosystems in the northern Rockies and its future is uncertain. The current decline of whitebark pine populations has been attributed to pine beetle infestations, blister rust infections, anthropogenic fire suppression, and climate change (Millar et al. 2012). Despite the knowledge that whitebark pine is severely threatened by multiple stressors, little is known about the historic capacity of this species to handle these stressors. More specifically, it is unknown how whitebark pine has dealt with past climatic variability, particularly variation in the type of precipitation (rain vs. snow) available for soil moisture, and how differences in quantity of precipitation have influenced the establishment and growth of modern stands. We propose to study the past responses of whitebark pine to paleoclimatic conditions, which would be useful to park ecologists in developing new conservation and regeneration plans to prevent the extinction of this already severely threatened high-elevation resource. The purpose of this study is to determine in great temporal and spatial detail the demographics of the current stand of whitebark pine trees in the watershed surrounding an unnamed, high-altitude pond (known informally as Whitebark Pine Moraine Pond) located approximately 3.06 miles NW of Jenny Lake in Grand Teton National Park (GTNP). The main objectives of this study were: 1.) To obtain the precise GPS locations of the current stand of whitebark pine trees in the watershed to generate a GIS map detailing their locations. 2.) To obtain increment cores of a subset of the trees in the watershed to estimate age and date of establishment for the current stand of whitebark pines, with particular attention to fire history. 3.) To analyze ring widths from core samples to identify climatic indicators that may influence the regeneration and survival of whitebark pine.

scholarly journals Future runoff regime changes and their time of emergence for 93 catchments in Switzerland

2020 ◽  
Author(s):  
Regula Muelchi ◽  
Ole Rössler ◽  
Jan Schwanbeck ◽  
Rolf Weingartner ◽  
Olivia Martius
Keyword(s):  
Climate Change ◽  
Strong Influence ◽  
Climate Model ◽  
High Elevation ◽  
Snow Accumulation ◽  
Seasonal Patterns ◽  
Climate Projections ◽  
Local Climate ◽  
Runoff Change ◽  
Runoff Changes

Abstract. Assessments of climate change impacts on runoff regimes are essential for adaptation and mitigation planning. Changing runoff regimes and thus changing seasonal patterns of water availability have strong influence on various sectors such as agriculture, energy production or fishery. In this study, we use the most up to date local climate projections for Switzerland (CH2018) that were downscaled with a post-processing method (quantile mapping). This enables detailed information on changes in runoff regimes and their time of emergence for 93 rivers in Switzerland under three emission pathways RCP2.6, RCP4.5, and RCP8.5. Changes in seasonal patterns are projected with increasing winter runoff and decreasing summer and autumn runoff. Spring runoff is projected to increase in high elevation catchments and to decrease in lower lying catchments. Despite strong increases in winter and partly in spring, the yearly mean runoff is projected to decrease in most catchments. Results show a strong elevation dependence for the signal and magnitude of change. Compared to lower lying catchments, runoff changes in high elevation catchments (above 1500 masl) are larger in winter, spring, and summer due to the strong influence of reduced snow accumulation and earlier snow melt as well as glacier melt. Under RCP8.5 (RCP2.6) and for catchments with mean altitude below 1500 masl, average relative runoff change in winter is +27 % (+5 %), in spring −5 % (−6 %), in summer −31 % (−4 %), in autumn −21 % (−6 %), and −8 % (−4 %) throughout the year. For catchments with mean elevation above 1500 masl, runoff changes on average by +77 % (+24 %) in winter, by +28 % (+16 %) in spring, by −41 % (−9 %) in summer, by −15 % (−4 %) in autumn, and by −9 % (−0.6 %) in the yearly mean. The changes and the climate model agreement on the signal of change increase with increasing global mean temperatures or stronger emission scenarios. This amplification highlights the importance of climate change mitigation. Under RCP8.5, early times of emergence in winter (before 2065; period 2036–2065) and summer (before 2065) were found for catchments with mean altitudes above 1500 masl. Significant changes in catchments below 1500 masl emerge later in the century. However, not all catchments show a time of emergence in all seasons and in some catchments the detected significant changes are not persistent over time.

Probabilistic projection of the regional climate as the basis for the development of adaptation programs in the economy of Russia

2021 ◽  
Author(s):  
Yuliya Rudakova ◽  
Igor Shkolnik ◽  
Elena Khlebnikova ◽  
Vladimir Kattsov
Keyword(s):  
Climate Change ◽  
Boundary Conditions ◽  
Thermal Regime ◽  
Initial Conditions ◽  
Climatic Variability ◽  
Regional Climate ◽  
Cmip5 Models ◽  
Northern Eurasia ◽  
Climate Projections ◽  
Russian Science

<p>The prospects of using the probabilistic regional climate projection technique for adaptation to climate change in the territory of Russia are considered. The analysis focuses on future changes in the climatic indicators of the thermal regime and humidification which play a significant role in the evaluation of the reliability of the functioning of construction and technical systems as well as transport and energy infrastructure.</p><p>The analysis is based on the output of the 50-member ensemble of high-resolution climate projections using an RCM developed at the Main Geophysical Observatory (MGO). The RCM grid has a horizontal resolution of 25 km across Russia. Modeling projections have been recently used to assess the impacts of regional climate change on hydropower facilities (Shkolnik et al., 2018).</p><p>Numerical experiments are carried out from different (random) initial conditions for the baseline 1990-1999 and future periods 2050-2059 and 2090-2099 using the IPCC RCP8.5 scenario (Kattsov et al., 2020). The boundary conditions on the ocean surface are derived from the output of the five CMIP5 models. For each ocean state trajectory, ten experiments from the different initial conditions are conducted. Lateral boundary conditions for the RCM ensemble are provided by MGO AGCM under an identical experimental setup.</p><p>To study the future impacts of the thermal regime, several universal indicators are used, particularly, the annual and seasonal extremes of temperature for a given averaging period as well as the characteristics of intra-annual periods with the temperature above/below the thresholds. The thresholds ​​are selected to meet the needs of construction, land transport, and the energy sector. Besides, the indicators of the precipitation regime are considered (seasonal maxima of daily amounts and characteristics of dry/wet periods).</p><p>Along with obtaining median ensemble estimates of changes in mean values, an analysis of future changes in the indicators in the probabilistic aspect is conducted. Using the temperature of the hottest 30-day period and the maximum duration of the dry period, the regional features of their projected changes are demonstrated accounting for the contribution of internal climatic variability. In agreement with observations, significant differences in the changes between the European part of Russia and certain regions of its Asian part are revealed.</p><p>The study is supported by the Russian Science Foundation (grant 16-17-00063).</p><p><strong>References</strong></p><p>Kattsov V., E. Khlebnikova, I. Shkolnik, and Yu. Rudakova: Probabilistic Regional Climate Projecting as a Basis for the Development of Adaptation Programs for the Economy of the Russian Federation. Russian Meteorology and Hydrology, 2020, Vol. 45, No. 5, pp. 330–338. Allerton Press, Inc., 2020.</p><p>Shkolnik, I., Pavlova, T., Efimov, S. et al. Future changes in peak river flows across northern Eurasia as inferred from an ensemble of regional climate projections under the IPCC RCP8.5 scenario. Clim Dyn 50<strong>, </strong>215–230 (2018). https://doi.org/10.1007/s00382-017-3600</p>

Holocene vegetation and climate change recorded in alpine bog sediments from the Borreguiles de la Virgen, Sierra Nevada, southern Spain

2012 ◽  
Vol 77 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Gonzalo Jiménez-Moreno ◽  
R. Scott Anderson
Keyword(s):  
Climate Change ◽  
Magnetic Susceptibility ◽  
High Resolution ◽  
Sierra Nevada ◽  
High Elevation ◽  
High Impact ◽  
Southern Spain ◽  
Pollen Record ◽  
Arboreal Pollen ◽  
Vegetation And Climate

High-resolution pollen and magnetic susceptibility (MS) analyses have been carried out on a sediment core taken from a high-elevation alpine bog area located in Sierra Nevada, southern Spain. The earliest part of the record, from 8200 to about 7000 cal yr BP, is characterized by the highest abundance of arboreal pollen andPediastrum, indicating the warmest and wettest conditions in the area at that time. The pollen record shows a progressive aridification since 7000 cal yr BP that occurred in two steps, first shown by a decrease inPinus, replaced by Poaceae from 7000 to 4600 cal yr BP and then by Cyperaceae,Artemisiaand Amaranthaceae from 4600 to 1200 cal yr BP.Pediastrumalso decreased progressively and totally disappeared at ca. 3000 yr ago. The progressive aridification is punctuated by periodically enhanced drought at ca. 6500, 5200 and 4000 cal yr BP that coincide in timing and duration with well-known dry events in the Mediterranean and other areas. Since 1200 cal yr BP, several changes are observed in the vegetation that probably indicate the high-impact of humans in the Sierra Nevada, with pasturing leading to nutrient enrichment and eutrophication of the bog,Pinusreforestation andOleacultivation at lower elevations.

scholarly journals Cold tolerance of mountain stoneflies (Plecoptera: Nemouridae) from the high Rocky Mountains

2020 ◽  
Author(s):  
Scott Hotaling ◽  
Alisha A. Shah ◽  
Michael E. Dillon ◽  
J. Joseph Giersch ◽  
Lusha M. Tronstad ◽  
...  
Keyword(s):  
Climate Change ◽  
Cold Tolerance ◽  
Rocky Mountains ◽  
High Elevation ◽  
Mountain Stream ◽  
Cold Temperatures ◽  
Thermal Limits ◽  
Late Instar ◽  
Stream Biodiversity ◽  
Common Association

ABSTRACTHow aquatic insects cope with cold temperatures is poorly understood. This is particularly true for high-elevation species that often experience a seasonal risk of freezing. In the Rocky Mountains, nemourid stoneflies (Plecoptera: Nemouridae) are a major component of mountain stream biodiversity and are typically found in streams fed by glaciers and snowfields, which due to climate change, are rapidly receding. Predicting the effects of climate change on mountain stoneflies is difficult because their thermal physiology is largely unknown. We investigated cold tolerance of several alpine stoneflies (Lednia tumana, Lednia tetonica, and Zapada spp.) from the Rocky Mountains, USA. We measured the supercooling point (SCP) and tolerance to ice enclosure of late-instar nymphs collected from a range of thermal regimes. SCPs varied among species and populations, with the lowest SCP measured for nymphs from an alpine pond, which is much more likely to freeze solid in winter than flowing streams. We also show that L. tumana cannot survive being enclosed in ice, even for short periods of time (less than three hours) at relatively mild temperatures (−0.5 °C). Our results indicate that high-elevation stoneflies at greater risk of freezing may have correspondingly lower SCPs, and despite their common association with glacial meltwater, they appear to be living near their lower thermal limits.

Timing and magnitude of runoff in Austrian mountain catchments in a warming climate

2021 ◽  
Author(s):  
Sarah Hanus ◽  
Harry Zekollari ◽  
Gerrit Schoups ◽  
Roland Kaitna ◽  
Markus Hrachowitz
Keyword(s):  
Climate Change ◽  
High Elevation ◽  
Climate Projections ◽  
Distributed Hydrological Model ◽  
Annual Maximum ◽  
Lower Elevation ◽  
Comprehensive Picture ◽  
Rcp 8.5 ◽  
Alpine Catchments ◽  
Maximum Flows

<p>Hydrological regimes of alpine catchments are expected to be strongly influenced by climate change due to their dependence on snow dynamics. While seasonal changes have been studied extensively, studies on changes in the timing and magnitude of annual extremes remain rare. This study investigates the effects of climate change on runoff patterns in six alpine catchments in Austria by using a topography-driven semi-distributed hydrological model and 14 climate projections for RCP 4.5 and RCP 8.5. The study catchments represent a range of alpine catchments, from pluvial-nival to nivo-glacial, as the study focuses on providing a comprehensive picture of future runoff changes on catchments at different altitudes. Simulations of 1981-2010 are compared to projections of 2071-2100 by examining changes in timing and magnitude of annual maximum and minimum flows as well as monthly discharges.</p><p>Our results indicate a substantial shift to earlier occurrences in annual maximum flows by 9 to 31 days on average and an extension of the potential flood season by 1 to 3 months for high elevation catchments. For lower elevation catchments, changes in timing of annual maximum flows are less pronounced. Magnitudes of annual maximum flows are likely to increase, with four catchments exhibiting larger increases under RCP 4.5 compared to RCP 8.5. The timing of minimum annual discharges shifts to earlier in the winter months for high elevation catchments, whereas for lower elevation catchments a shift from winter to autumn is observed. While all catchments show an increase in mean magnitude of minimum flows under RCP 4.5, this is not the case for two low elevation catchments under RCP 8.5.</p><p>Our results suggest a relationship between the altitude of catchments and changes in timing of annual maximum and minimum flows and magnitude of low flows, whereas no relationship between altitude and magnitude of annual maximum flows could be distinguished.</p>

scholarly journals Temporal and Spatial Characteristics of Precipitation and Temperature in Punjab, Pakistan

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1916 ◽  
Author(s):  
Nawaz ◽  
Li ◽  
Chen ◽  
Guo ◽  
Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Climatic Variability ◽  
Regional Scale ◽  
Elevation Gradient ◽  
High Elevation ◽  
Maximum Temperature ◽  
Moderate Increase ◽  
Study Region ◽  
Lower Elevation ◽  
Precipitation And Temperature

Identifying the changes in precipitation and temperature at a regional scale is of great importance for the quantification of climate change. This research investigates the changes in precipitation and surface air temperature indices in the seven irrigation zones of Punjab Province during the last 50 years; this province is a very important region in Pakistan in terms of agriculture and irrigated farming. The reliability of the data was examined using double mass curve and autocorrelation analysis. The magnitude and significance of the precipitation and temperature were visualized by various statistical methods. The stations’ trends were spatially distributed to better understand climatic variability across the elevation gradient of the study region. The results showed a significant warming trend in annual Tmin (minimum temperature) and Tmean (mean temperature) in different irrigation zones. However, Tmax (maximum temperature) had insignificant variations except in the high elevation Thal zone. Moreover, the rate of Tmin increased faster than that of Tmax, resulting in a reduction in the diurnal temperature range (DTR). On a seasonal scale, warming was more pronounced during spring, followed by that in winter and autumn. However, the summer season exhibited insignificant negative trends in most of the zones and gauges, except in the higher-altitude Thal zone. Overall, Bahawalpur and Faisalabad are the zones most vulnerable to warming annually and in the spring, respectively. Furthermore, the elevation-dependent trend (EDT) indicated larger increments in Tmax for higher-elevation (above 500 m a.s.l.) stations, compared to the lower-elevation ones, on both annual and seasonal scales. In contrast, the Tmin showed opposite trends at higher- and lower-elevation stations, while a moderate increase was witnessed in Tmean trends from lower to higher altitude over the study region. An increasing trend in DTR was observed at higher elevation, while a decreasing trend was noticed at the lower-elevation stations. The analysis of precipitation data indicated wide variability over the entire region during the study period. Most previous studies reported no change or a decreasing trend in precipitation in this region. Conversely, our findings indicated the cumulative increase in annual and autumn precipitation amounts at zonal and regional level. However, EDT analysis identified the decrease in precipitation amounts at higher elevation (above 1000 m a.s.l.) and increase at the lower-elevation stations. Overall, our findings revealed unprecedented evidence of regional climate change from the perspectives of seasonal warming and variations in precipitation and temperature extremes (Tmax and Tmin) particularly at higher-elevation sites, resulting in a variability of the DTR, which could have a significant influence on water resources and on the phenology of vegetation and crops at zonal and station level in Punjab.

scholarly journals Climate anomalies associated to the occurrence of rockfalls at high-elevation in the Italian Alps

2016 ◽  
Author(s):  
Roberta Paranunzio ◽  
Francesco Laio ◽  
Marta Chiarle ◽  
Guido Nigrelli ◽  
Fausto Guzzetti
Keyword(s):  
Climate Change ◽  
Slope Failure ◽  
High Elevation ◽  
Slope Instability ◽  
Slope Failures ◽  
Italian Alps ◽  
Regional Patterns ◽  
Climate Anomalies ◽  
Permafrost Thaw ◽  
The Impact

Abstract. Climate change is seriously affecting the cryosphere, in terms, for example of permafrost thaw, alteration of rain/snow ratio, glacier shrinkage. There is concern about the increasing number of rockfalls at high elevation in the last decades. Nevertheless, the impact of climate variables on slope instability at high elevation has not been fully explored yet. In this paper, we investigate 41 rockfalls occurred at high elevation in the Italian Alps between 1997 and 2013 in the absence of an evident trigger. We apply and improve an existing data-based, statistical approach to detect the anomalies of climate parameters (temperature and precipitation) associated to rockfall occurrences. The identified climate anomalies have been related to the spatio-temporal distribution of the events. Rockfalls occurred in association with temperature anomalies in 83 % of our case studies. Temperature represents a key factor contributing to slope failure occurrence in different ways. As expected, warmer temperatures accelerate snowmelt and permafrost thaw; however, surprisingly, negative anomalies are also often associated to slope failures. Interestingly, different regional patterns emerge from the data: higher-than-average temperatures are often associated to rockfalls in the Western Alps, while in the Eastern Alps slope failures are mainly associated to colder-than-average temperatures. The results of this study represent a first step towards the identification of the possible role of climate change in the triggering of slope failures in a mountain environment.

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