Assessing the ecological value of  dynamic mountain geomorphosites

Abstract. Geoheritage is a component of geodiversity constituted by all the elements of geodiversity recognized by society for their particular values. The definition of these values, including the importance of geoheritage for biodiversity, plays a key role in the process of heritage recognition and geoconservation policymaking. In mountain environments, dynamic geomorphosites have a strong influence on plant diversity because the active geomorphological processes responsible for their formation act as renovators for habitats of pioneer species. In this paper, we propose criteria to assess the ecological value of dynamic mountain geomorphosites. We show that the interest of plant communities (species richness and presence of rare or protected species) and the influence of geomorphological processes on plant communities (disturbances, surface movement and soil) are fundamental criteria for assessing the ecological value in an exhaustive and objective way and that the question of the scale (local and national scales) is also a crucial parameter. We then illustrate this methodological proposal by evaluating the ecological value of three dynamic geomorphosites and a talus slope in the western Swiss Alps.

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Assessing the ecological value of dynamic mountain geomorphosites

10.5194/egusphere-egu21-253 ◽

2021 ◽

Author(s):

Jonathan Bussard ◽

Elisa Giaccone

Keyword(s):

Cultural Values ◽

Objective Assessment ◽

Swiss Alps ◽

Ice Age ◽

Ecological Value ◽

Complete Evaluation ◽

Vegetation Diversity ◽

Animal Diversity ◽

Geomorphological Parameters ◽

Geomorphological Processes

Over the last 15 years, the methodological proposals for assessing the heritage value of geomorphosites have been numerous and varied (Brilha, 2018). While some of the main criteria for assessing the geoscientific value, i.e. the interest for Earth sciences (rarity, representativeness, integrity), are mentioned in most methods, the criteria for assessing additional values (Reynard, 2005, 2009: &#160;aesthetic, ecological and cultural values) are much more heterogeneous (Mucivuna et al., 2019). There is particularly little discussion in the literature about the assessment of the ecological value of geomorphosites. Many case studies suggest to give a high score when &#8220;valuable&#8221; or &#8220;interesting&#8221; fauna and/or flora are observed, without explaining the link with a specific geomorphological landform or process. A few authors, such as Bollati et al. (2015), proposed to assess the &#8220;ecologic support role&#8221;, i.e. the impacts of geomorphological processes and landforms on vegetal and animal diversity or their contribution to ecosystem services. Despite these suggestions, there is still no detailed methodological proposal to assess the ecological value of geomorphosites based on clearly defined criteria.The bi-directional relationship between geomorphology and biological elements of nature has been the subject of many publications and led to the development of the biogeomorphology, defined as the study of interactions between geomorphological processes and structures and living organisms, like plants, animals and microorganisms (e.g. Knox, 1972; Butler, 1995; Gorbushina, 2007). Compared to other categories of geosites, the activity of processes responsible for their formation and evolution is often a core characteristic of geomorphosites (Reynard, 2009; Pelfini and Bollati, 2014; Coratza and Hobl&#233;a, 2018) and this dynamic can have a strong influence on vegetation. This is especially the case in mountain environment, where dynamic geomorphological parameters can have various effects on vegetation distribution and community composition (Giaccone et al., 2019).The aim of this communication is to clarify and objectivize the assessment of the ecological value of dynamic mountain geomorphosites. A complete evaluation of the ecological value should take into account the impacts of geomorphological processes and landforms on vegetation and fauna diversity. Here we propose to look further into the question of the influence of dynamic mountain geomorphosites on vegetation diversity. We suggest the definition of three criteria &#8211; disturbances, microhabitats, types of substrates &#8211; that should be used for a more accurate and objective assessment of the ecological value of this category of geomorphosites, with a particular focus on the links between geomorphology and vegetal biodiversity. We finally apply these criteria for the assessment of the ecological value of four mountain geomorphosites situated in the Vallon de Nant (Swiss Alps): a rock glacier, a moraine complex from the Younger Dryas, a side and frontal moraine from the Little Ice Age and a zone of scree slopes and avalanche deposits.

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On the value of high density rain gauge observations for small Alpine headwater catchment hydrology

10.5194/hess-2020-371 ◽

2020 ◽

Author(s):

Anthony Michelon ◽

Lionel Benoit ◽

Harsh Beria ◽

Natalie Ceperley ◽

Bettina Schaefli

Keyword(s):

Low Cost ◽

Rain Gauge ◽

High Density ◽

Swiss Alps ◽

Hydrologic Response ◽

Catchment Scale ◽

Stream Network ◽

Rain Gauges ◽

Mountain Environments ◽

Definition Of

Abstract. Spatial rainfall patterns exert a key control on the catchment scale hydrologic response. Despite recent advances in radar-based rainfall sensing, rainfall observation remains a challenge particularly in mountain environments. This paper analyzes the importance of high-density rainfall observations for a 13.4 km2 catchment located in the Swiss Alps where rainfall events were monitored during 3 summer months using a network of 12 low-cost, drop-counting rain gauges. We developed a data-based analysis framework to assess the importance of high-density rainfall observations to help predict hydrologic processes. The framework involves the definition of spatial rainfall distribution metrics based on hydrological and geomorphological considerations, and the analysis of how these metrics explain the hydrologic response in terms of runoff coefficient and lag time. The gained insights are then used to investigate the optimal raingauge network density for predicting the hydrological metrics in the studied catchment. The analysis unravels that besides amount and intensity, the rainfall distance from the outlet along the stream network is a key spatial rainfall metric. This result calls for more detailed observations of stream network expansions, as well as the parameterization of along stream processes in rainfall-runoff models. In addition, despite the small spatial scale of this case study, the results show that an accurate representation of the rainfall field is of prime importance to capture the key characteristics of the hydrologic response in terms of generated runoff volumes and delay. In the present case, at least three rain gauges were required for proper runoff prediction.

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The Relict Ecosystem of Maytenus senegalensis subsp. europaea in an Agricultural Landscape: Past, Present and Future Scenarios

Land ◽

10.3390/land10010001 ◽

2020 ◽

Vol 10 (1) ◽

pp. 1

Author(s):

Antonio J. Mendoza-Fernández ◽

Fabián Martínez-Hernández ◽

Esteban Salmerón-Sánchez ◽

Francisco J. Pérez-García ◽

Blas Teruel ◽

...

Keyword(s):

Plant Communities ◽

Ecological Niche ◽

Agricultural Landscape ◽

Agricultural Landscapes ◽

Eastern Coast ◽

Ecological Value ◽

Distribution Models ◽

European Continent ◽

Major Interest ◽

Maytenus Senegalensis

Maytenus senegalensis subsp. europaea is a shrub belonging to the Celastraceae family, whose only European populations are distributed discontinuously along the south-eastern coast of the Iberian Peninsula, forming plant communities with great ecological value, unique in Europe. As it is an endangered species that makes up plant communities with great palaeoecological significance, the development of species distribution models is of major interest under different climatic scenarios, past, present and future, based on the fact that the climate could play a relevant role in the distribution of this species, as well as in the conformation of the communities in which it is integrated. Palaeoecological models were generated for the Maximum Interglacial, Last Maximum Glacial and Middle Holocene periods. The results obtained showed that the widest distribution of this species, and the maximum suitability of its habitat, occurred during the Last Glacial Maximum, when the temperatures of the peninsular southeast were not as contrasting as those of the rest of the European continent and were favored by higher rainfall. Under these conditions, large territories could act as shelters during the glacial period, a hypothesis reflected in the model’s results for this period, which exhibit a further expansion of M. europaea’s ecological niche. The future projection of models in around 2070, for four Representative Concentration Pathways according to the fifth report of the Intergovernmental Panel on Climate Change, showed that the most favorable areas for this species would be Campo de Dalías (southern portion of Almería province) as it presents the bioclimatic characteristics of greater adjustment to M. europaea’s ecological niche model. Currently, some of the largest specimens of the species survive in the agricultural landscapes in the southern Spain. These areas are almost totally destroyed and heavily altered by intensive agriculture greenhouses, also causing a severe fragmentation of the habitat, which implies a prospective extinction scenario in the near future.

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Holocene landslide activity in the Western Swiss Alps – a consequence of vegetation changes and climate oscillations

Landslides ◽

10.1201/9780203749197-47 ◽

2018 ◽

pp. 349-354

Author(s):

F. Dapples ◽

D. Oswald ◽

H. Raetzo

Keyword(s):

Swiss Alps ◽

Vegetation Changes ◽

Climate Oscillations ◽

Landslide Activity ◽

Western Swiss Alps

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Multiscale Very-High Resolution Topographic Models in Alpine Ecology: Pros and Cons of Airborne LiDAR and Drone-Based Stereo-Photogrammetry Technologies

10.20944/preprints202103.0581.v1 ◽

2021 ◽

Author(s):

Annie S. Guillaume ◽

Kevin Leempoel ◽

Estelle Rochat ◽

Aude Rogivue ◽

Michel Kasser ◽

...

Keyword(s):

Species Distribution Modelling ◽

Airborne Lidar ◽

Swiss Alps ◽

The Arctic ◽

Site Characteristics ◽

Digital Elevation ◽

Stereo Photogrammetry ◽

Arabis Alpina ◽

Western Swiss Alps ◽

Very High

The vulnerability of alpine environments to climate change presses an urgent need to accurately model and understand these ecosystems. Popularity in use of digital elevation models (DEMs) to derive proxy environmental variables has increased over the past decade, particularly as DEMs are relatively cheaply acquired at very high resolutions (VHR; <1m spatial resolution). Here, we implement a multiscale framework and compare DEM-derived variables produced by Light Detection and Ranging (LiDAR) and stereo-photogrammetry (PHOTO) methods, with the aims of assessing their relevance and utility in species distribution modelling (SDM). Using a case study on the arctic-alpine plant Arabis alpina in two valleys in the western Swiss Alps, we show that both LiDAR and PHOTO technologies can be relevant for producing DEM-derived variables for use in SDMs. We demonstrate that PHOTO DEMs rivalled the accuracy of LiDAR, putting the current paradigm of LiDAR being the more accurate of the two methods into question. We obtained DEMs at spatial resolutions of 6.25cm-8m for PHOTO and 50cm-32m for LiDAR, where we determined that the optimal spatial resolutions of DEM-derived variables in SDM were between 1 and 32m, depending on the variable and site characteristics. We found that the reduced extent of PHOTO DEMs altered the calculations of all derived variables, which had particular consequences on their relevance at the site with heterogenous terrain. However, for the homogenous site, we found that SDMs based on PHOTO-derived variables generally had higher predictive powers than those derived from LiDAR at matching resolutions. From our results, we recommend carefully considering the required DEM extent to produce relevant derived variables. We also advocate implementing a multiscale framework to appropriately assess the ecological relevance of derived variables, where we caution against the use of VHR-DEMs finer than 50cm in such studies.

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Influence of microclimate and geomorphological factors on alpine vegetation in the Western Swiss Alps

Earth Surface Processes and Landforms ◽

10.1002/esp.4715 ◽

2019 ◽

Vol 44 (15) ◽

pp. 3093-3107 ◽

Cited By ~ 5

Author(s):

Elisa Giaccone ◽

Miska Luoto ◽

Pascal Vittoz ◽

Antoine Guisan ◽

Grégoire Mariéthoz ◽

...

Keyword(s):

Swiss Alps ◽

Alpine Vegetation ◽

Western Swiss Alps

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Spatial relationship between the atmospheric circulation and the precipitation measured in the western Swiss Alps by means of the analogue method

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-777-2012 ◽

2012 ◽

Vol 12 (3) ◽

pp. 777-784 ◽

Cited By ~ 23

Author(s):

P. Horton ◽

M. Jaboyedoff ◽

R. Metzger ◽

C. Obled ◽

R. Marty

Keyword(s):

Atmospheric Circulation ◽

Precipitation Amount ◽

Heavy Precipitation ◽

Swiss Alps ◽

Precipitation Event ◽

Circulation Patterns ◽

Analogue Method ◽

Western Swiss Alps ◽

Time Extrapolation ◽

Precipitation Events

Abstract. An adaptation technique based on the synoptic atmospheric circulation to forecast local precipitation, namely the analogue method, has been implemented for the western Swiss Alps. During the calibration procedure, relevance maps were established for the geopotential height data. These maps highlight the locations were the synoptic circulation was found of interest for the precipitation forecasting at two rain gauge stations (Binn and Les Marécottes) that are located both in the alpine Rhône catchment, at a distance of about 100 km from each other. These two stations are sensitive to different atmospheric circulations. We have observed that the most relevant data for the analogue method can be found where specific atmospheric circulation patterns appear concomitantly with heavy precipitation events. Those skilled regions are coherent with the atmospheric flows illustrated, for example, by means of the back trajectories of air masses. Indeed, the circulation recurrently diverges from the climatology during days with strong precipitation on the southern part of the alpine Rhône catchment. We have found that for over 152 days with precipitation amount above 50 mm at the Binn station, only 3 did not show a trajectory of a southerly flow, meaning that such a circulation was present for 98% of the events. Time evolution of the relevance maps confirms that the atmospheric circulation variables have significantly better forecasting skills close to the precipitation period, and that it seems pointless for the analogue method to consider circulation information days before a precipitation event as a primary predictor. Even though the occurrence of some critical circulation patterns leading to heavy precipitation events can be detected by precursors at remote locations and 1 week ahead (Grazzini, 2007; Martius et al., 2008), time extrapolation by the analogue method seems to be rather poor. This would suggest, in accordance with previous studies (Obled et al., 2002; Bontron and Obled, 2005), that time extrapolation should be done by the Global Circulation Model, which can process atmospheric variables that can be used by the adaptation method.

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