Recent snow cover changes over central European low mountain ranges

2019 ◽  
Vol 34 (2) ◽  
pp. 321-338 ◽  
Author(s):  
Chunyu Dong ◽  
Lucas Menzel
Keyword(s):  
Snow Cover ◽  
Central European ◽  
Mountain Ranges ◽  
Low Mountain Ranges

scholarly journals Palaeoecology as a Tool for the Future Management of Forest Ecosystems in Hesse (Central Germany): Beech (Fagus sylvatica L.) versus Lime (Tilia cordata Mill.)

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 924
Author(s):  
Astrid Stobbe ◽  
Maren Gumnior
Keyword(s):  
Fagus Sylvatica ◽  
Tilia Cordata ◽  
Beech Forests ◽  
Mountain Ranges ◽  
The Future ◽  
Spruce Stands ◽  
Fagus Sylvatica L ◽  
Low Mountain Ranges ◽  
Intramontane Basins ◽  
Future Management

In the Central German Uplands, Fagus sylvatica and Picea abies have been particularly affected by climate change. With the establishment of beech forests about 3000 years ago and pure spruce stands 500 years ago, they might be regarded as ‘neophytes’ in the Hessian forests. Palaeoecological investigations at wetland sites in the low mountain ranges and intramontane basins point to an asynchronous vegetation evolution in a comparatively small but heterogenous region. On the other hand, palynological data prove that sustainably managed woodlands with high proportions of Tilia have been persisting for several millennia, before the spread of beech took place as a result of a cooler and wetter climate and changes in land management. In view of increasingly warmer and drier conditions, Tilia cordata appears especially qualified to be an important silvicultural constituent of the future, not only due to its tolerance towards drought, but also its resistance to browsing, and the ability to reproduce vegetatively. Forest managers should be encouraged to actively promote the return to more stress-tolerant lime-dominated woodlands, similar to those that existed in the Subboreal chronozone.

scholarly journals Are there signs of acidification reversal in freshwaters of the low mountain ranges in Germany?

2001 ◽  
Vol 5 (3) ◽  
pp. 367-378 ◽  
Author(s):  
C. Alewell ◽  
M. Armbruster ◽  
J. Bittersohl ◽  
C. D. Evans ◽  
H. Meesenburg ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Extreme Values ◽  
Stream Water ◽  
Base Cation ◽  
Drinking Water Supply ◽  
Mountain Ranges ◽  
Acid Neutralising Capacity ◽  
Freshwater Acidification ◽  
Low Mountain Ranges

Abstract. The reversal of freshwater acidification in the low mountain ranges of Germany is of public, political and scientific concern, because these regions are near natural ecosystems and function as an important drinking water supply. The aim of this study was to evaluate the status and trends of acidification reversal after two decades of reduced anthropogenic deposition in selected freshwaters of the low mountain ranges in the Harz, the Fichtelgebirge, the Bavarian Forest, the Spessart and the Black Forest. In response to decreased sulphate deposition, seven out of nine streams investigated had significantly decreasing sulphate concentrations (all trends were calculated with the Seasonal Kendall Test). The decrease in sulphate concentration was only minor, however, due to the release of previously stored soil sulphur. No increase was found in pH and acid neutralising capacity (defined by Reuss and Johnson, 1986). Aluminum concentrations in the streams did not decrease. Thus, no major acidification reversal can currently be noted in spite of two decades of decreased acid deposition. Nevertheless, the first signs of improvement in water quality were detected as there was a decrease in the level and frequency of extreme values of pH, acid neutralising capacity and aluminium concentrations in streams. With respect to nitrogen, no change was determined for either nitrate or ammonium concentrations in precipitation or stream water. Base cation fluxes indicate increasing net loss of base cations from all ecosystems investigated, which could be interpreted as an increase in soil acidification. The latter was due to a combination of continued high anion leaching and significant reduction of base cation deposition. No major improvement was noted in biological recovery, however, initial signs of recovery were detectable as there was re-occurrence of some single macroinvertebrate species which were formerly extinct. The results of this study have important implications for water authorities, forest managers and policy makers: the delay in acidification reversal suggests a need for ongoing intensive amelioration of waters, a careful selection of management tools to guarantee sustainable management of forests and the reduction of nitrogen deposition to prevent further acidification of soils and waters. Keywords: freshwater, acidification reversal, drinking water supply, forested catchments, Germany

scholarly journals Different forest cover and its impact on eco-hydrological traits, invertebrate fauna and biodiversity of spring habitats

2018 ◽  
Vol 27 ◽  
pp. 85-99 ◽  
Author(s):  
Martin Reiss ◽  
Peter Chifflard
Keyword(s):  
Management Practices ◽  
Forest Cover ◽  
Deciduous Forest ◽  
Coniferous Forest ◽  
Morphological Structure ◽  
Conifer Forest ◽  
Substrate Type ◽  
Structure Mapping ◽  
Mountain Ranges ◽  
Low Mountain Ranges

Headwater springs in the German Low Mountain Ranges are local ecotone habitats and biogeographical islands embedded in and interlinked with their adjacent landscape. The structure of forests reflects the eco-hydrological conditions in substrate type occurrence, microhabitat richness and biodiversity in forest springs. This study considers effects from different forest land cover by comparing spring habitats in deciduous beech forests and coniferous spruce forests on eco-hydrological structures and biodiversity. Study areas include six different forest landscapes in the Low Mountain Ranges in Central Germany in Hesse and Thuringia. Hydro-morphological structure mapping and invertebrate sampling was executed within a multi-habitat sampling regime, which involves sampling plots being allocated according to the cover ratio of the occurring substrata. Aquatic and terrestrial spring zones are considered with respect to an ecotone approach. Some in situ measurements were implemented, such as pH values, to assess the acidity of the spring water. Results show obvious differences in acidity, substrate type cover ratios and biodiversity in deciduous and coniferous forest springs. Conifer forest springs were found tending to acidification while deciduous forest springs were slightly alkaline. Deciduous forest springs had higher cover ratios of organic microhabitats as well as a higher biodiversity in species richness and total number of individuals. Although it was not possible to clearly distinguish one direct key factor of fauna assemblages, negative effects from forest management practices (e.g. monoculture plantations of conifer forest) on spring habitats can be concluded.

Role of Saharan dust and black carbon deposition on snow cover in the French mountain ranges over the last 39 years.

2020 ◽  
Author(s):  
Marion Réveillet ◽  
Marie Dumont ◽  
Simon Gascoin ◽  
Pierre Nabat ◽  
Matthieu Lafaysse ◽  
...  
Keyword(s):  
Snow Cover ◽  
Black Carbon ◽  
Carbon Deposition ◽  
Mineral Dust ◽  
Explicit Representation ◽  
Dust Deposition ◽  
Mountain Ranges ◽  
Annual Variability ◽  
Snow Cover Duration ◽  
The Impact

<p>Light absorbing particles such as black carbon(BC) or mineral dust are known to darken the snow surface when deposited on the snow cover and amplify several snow-albedo feedbacks, drastically modifying the snowpack evolution and the snow cover duration. Mineral dust deposition on snow is generally more variablein time than black carbon deposition and can exhibit both a high inter and intra annual variability. In France, the Alps and the Pyrenees mountain ranges are affected by large dust deposition events originating from the Sahara . The aim of this study is to quantify the impact of these impurities on the snow cover variability over the last 39 years (1979-2018).</p><p>For that purpose, the detailed snowpack model Crocus with an explicit representation of impurities is forced by SAFRAN meteorological reanalysis and a downscaling of the simulated deposition fluxes from a regional climate model (ALADIN-Climate). Different simulations are performed: (i) considering dust and/or BC (i.e. explicit representation), (ii) without impurities and (iii) considering an implicit representation (i.e. empirical parameterization based on a decreasing law of the albebo with snow age).</p><p>Simulations are compared at point scale to the snow depth measured at more than 200 Meteo-France’s stations in each massif, and spatially evaluated over the 2000-2018 period in comparing thesnow cover area, snow cover duration and the Jacard index to MODIS snow products. Scores are generally better when considering the explicit representation of the impurities than when using the snow age as a proxy for light absorbing particles content.</p><p>Results indicate that dust and BC have a significant impact on the snow cover duration with strong variations in the magnitude of the impact from one year to another and from one location to another.We also investigate the contribution of light absorbing particles depositionto snow cover inter-annual variability based on statistical approaches.</p>

scholarly journals MODIS Does Not Capture the Spatial Heterogeneity of Snow Cover Induced by Solar Radiation

2021 ◽  
Vol 9 ◽  
Author(s):  
Hafsa Bouamri ◽  
Christophe Kinnard ◽  
Abdelghani Boudhar ◽  
Simon Gascoin ◽  
Lahoucine Hanich ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Spatial Variability ◽  
Snow Cover ◽  
Model Performance ◽  
Added Value ◽  
Snow Cover Area ◽  
Temperature Index ◽  
Mountain Ranges ◽  
Clear Sky ◽  
Spatially Distributed

Estimating snowmelt in semi-arid mountain ranges is an important but challenging task, due to the large spatial variability of the snow cover and scarcity of field observations. Adding solar radiation as snowmelt predictor within empirical snow models is often done to account for topographically induced variations in melt rates. This study examines the added value of including different treatments of solar radiation within empirical snowmelt models and benchmarks their performance against MODIS snow cover area (SCA) maps over the 2003-2016 period. Three spatially distributed, enhanced temperature index models that, respectively, include the potential clear-sky direct radiation, the incoming solar radiation and net solar radiation were compared with a classical temperature-index (TI) model to simulate snowmelt, SWE and SCA within the Rheraya basin in the Moroccan High Atlas Range. Enhanced models, particularly that which includes net solar radiation, were found to better explain the observed SCA variability compared to the TI model. However, differences in model performance in simulating basin wide SWE and SCA were small. This occurs because topographically induced variations in melt rates simulated by the enhanced models tend to average out, a situation favored by the rather uniform distribution of slope aspects in the basin. While the enhanced models simulated more heterogeneous snow cover conditions, aggregating the simulated SCA from the 100 m model resolution towards the MODIS resolution (500 m) suppresses key spatial variability related to solar radiation, which attenuates the differences between the TI and the radiative models. Our findings call for caution when using MODIS for calibration and validation of spatially distributed snow models.

2. Ancient reefs and islands

2021 ◽  
pp. 12-19
Author(s):  
Charles Sheppard
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Geological Time ◽  
Vast Array ◽  
Mountain Ranges ◽  
Island Type ◽  
Coral Island ◽  
Low Mountain Ranges ◽  
Limestone Rock ◽  
Tabulate Corals

Reefs in deep geological time have been built by a succession of different kinds of life: plant, bacterial, and animal. Stromatolites and bryozoans were major reef-builders that persist today in minor or non-reef-building forms, sponges built entire reefs and are still important reef components, while several groups of major reef-builders flourished for a while and then became extinct: archaeocyathids which were similar to sponges, and coral-like forms including rugose and tabulate corals. Today’s reef-builders, cnidarian corals, appeared well after the great Permian-Triassic extinction event. All of these groups deposited vast quantities of limestone rock on which they live, often visible today as low mountain ranges. Reefs grow to the surface but not beyond, but upon them sand and sediments may build up, forming an island that attracts plants, then birds and other terrestrial forms of life. The sediments become cemented with the aid of rainwater too, and ‘low islands’ develop. Many islands also show their old, central volcanoes, resulting in the vast array of different combinations of coral island type. Today, however, there is a coral reef crisis due to overexploitation of a reef’s rich resources, from pollution of several kinds, and climate change.

Sign in / Sign up

Export Citation Format

Share Document