Gran Paradiso National Park Research Articles

Wolf and wild boar in the Alps: Trophic, temporal and spatial interactions in an Alpine protected area

In predator-prey systems, interspecific interactions at the spatial and temporal scale may affect different components of the ecosystem. Despite a growing interest in the topic, little is known about these interactions in many regions, particularly in areas recently recolonized by apex predators, such as the Alps. Using a multidimensional approach, we assessed wolf-wild boar interactions in a recently recolonized protected area of the Western Alps (Gran Paradiso National Park, Italy) by combining camera trapping and wolf scat analyses. First, we quantified the importance of wild boar in the wolf diet by comparing two different periods (October 2018–September 2020 vs. October 2021–September 2022). Second, we evaluated prey selection in 2021–2022, when data on prey availability were collected. Then, we assessed spatiotemporal interactions between the wild boar and the wolf. Finally, we calculated combined spatiotemporal associations between the wolf and the wild boar in comparison to other ungulate prey. We found a remarkable increase in wild boar consumption between the two periods; roe deer and wild boar were consumed in proportion to their availability, while the chamois was positively selected and the red deer and the ibex were less consumed in relation to their availability. Although we found no negative association between wolf and wild boar detection rates, in winter the wild boar limited its temporal overlap with the predator by being less active in sites more frequently used by the wolf, suggesting some spatial modulation of a temporal antipredator response. Among ungulate species, the wild boar had the highest combined spatiotemporal association with the wolf, particularly in autumn-winter. Our results suggest complex interspecific interactions in alpine areas recently recolonized by the wolf.

Climate drives body mass changes in a mountain ungulate: shorter winters lead to heavier Alpine ibex

Climate affects seasonality and plant phenology, which can influence seasonal body mass dynamics of herbivores in temperate environments. We investigated long‐term trends of seasonal body mass changes in male Alpine ibex Capra ibex. We used SEM to test direct and indirect relationships between body mass, mass changes and environmental and climatic variables. Individually recognizable Alpine ibex were weighed repeatedly between 2000 and 2022 in Gran Paradiso National Park (Italy). Autumn mass increased substantially over these two decades, up to 15% in some age classes. Over the same time frame, both summer mass gain and winter mass loss decreased, suggesting that heavier autumn body mass was due to the cumulative effects of reduced mass loss over several winters. The environmental factor with the strongest effects on winter mass changes was the starting date of vegetation green‐up at low altitude, where ibex gather after winter to feed on new growth vegetation. Early springs led to lower winter mass loss, likely because ibex relied on stored fat for a shorter period and had greater access to forage. High population density also increased winter mass loss. Environmental conditions and resource availability, possibly also influenced by density in winter and early spring, seem therefore to directly affect the body mass dynamics of male Alpine ibex, while the effect of summer conditions appears less relevant. By affecting seasonal body mass dynamics, climate change may have consequences for life history and population dynamics of mountain herbivores, for example via earlier access of young males to reproduction.

Faster than expected: 5-year re-surveys reveal accelerating plant colonization in two proglacial forelands of the Gran Paradiso National Park (NW Italian Alps)

Abstract Proglacial vegetation communities are facing major challenges today due to fast glacier retreat and global warming, resulting in possible changes in plant colonization patterns. By re-surveying permanent plots along two alpine chronosequences (encompassing 5 to 165 years from deglaciation) with a 5-year time span, we aimed to (i) assess short-term vegetation changes and (ii) compare current vegetation trajectories with those predicted by the chronosequence approach. We analysed the number and cover of total, pioneer, and alpine grassland species and calculated the slopes of the trajectories of the chronosequence and observed on permanent plots. As expected, the number and cover of total, pioneer, and grassland species increased during the 5 years of the study. Moreover, we observed a significant acceleration in plant colonization (21 and 45 times faster increase in species richness and cover, respectively) compared to the chronosequence predictions. These dramatic changes in vegetation dynamics of proglacial plant communities were probably induced by the increased temperatures and longer growing seasons occurring in the Alps.

Carbon dioxide fluxes in Alpine grasslands at the Nivolet Plain, Gran Paradiso National Park, Italy 2017–2023

We introduce a georeferenced dataset of Net Ecosystem Exchange (NEE), Ecosystem Respiration (ER) and meteo-climatic variables (air and soil temperature, air relative humidity, soil volumetric water content, pressure, and solar irradiance) collected at the Nivolet Plain in Gran Paradiso National Park (GPNP), western Italian Alps, from 2017 to 2023. NEE and ER are derived by measuring the temporal variation of CO2 concentration obtained by the enclosed chamber method. We used a customised portable non-steady-state dynamic flux chamber, paired with an InfraRed Gas Analyser (IRGA) and a portable weather station, measuring CO2 fluxes at a number of points (around 20 per site and per day) within five different sites during the snow-free season (June to October). Sites are located within the same hydrological basin and have different geological substrates: carbonate rocks (site CARB), gneiss (GNE), glacial deposits (GLA, EC), alluvial sediments (AL). This dataset provides relevant and often missing information on high-altitude mountain ecosystems and enables new comparisons with other similar sites, modelling developments and validation of remote sensing data.

Modelling the effects of potential climate change on the dynamics of multi-species mountain pastures: A case study in Gran Paradiso National Park, Italy

CONTEXTPasture dynamics of Alpine areas are linked to the complex cryospheric hydrology of Alpine catchment and to the interspecies competition, which are in turn expected to change remarkably under prospective global warming scenarios. OBJECTIVEThis study aimed at assessing the impact of climate change on the productivity of mountain pastures in the Gran Paradiso National Park (Italy). METHODSThe hydrological model Poli-Hydro was used, coupled with the Poli-Pasture model, able to simulate pasture growth, which was further integrated with CoSMo model to consider interspecific competition. Two (competing) species were chosen for low altitude LowAlt areas (below 1800 m asl), Trifolium alpinum and Dactylis glomerata, and two for high altitude HighAlt areas (above 1800 m asl), Festuca rubra and Nardus stricta. Model tuning and evaluation were performed against estimates of leaf area index (LAI), derived from satellite imagery during 2005–2019. Then, climate change impacts were projected until 2100 by considering four IPCC AR6 scenarios and six GCMs. Target variables included a set of agroclimatic indices, LAI and pasture yield. RESULTS AND CONCLUSIONSDue to the projected increase in temperatures during the XXI century, a measurable potential increase in productivity would be expected, especially in the highest areas (up to +97% by 2050, and + 123% by 2100 for the SSP5–8.5 scenario). The relative abundance of pasture species appears to remain mostly stable; at most, the species with higher fodder value even increases slightly. This suggests that a loss in the overall quality of biomass should not occur. These results provide preliminary evidence for the potential development of livestock farming, and thus of a relevant part of the economy in the valleys, at higher altitudes than now. However, to a certain extent pasture performance could be threatened by the projected reduction in summer rainfall, and possibly spreading of pests with increasing temperature. SIGNIFICANCEThe results obtained here could be useful for policy makers, and scientists in the field of pasture/grasslands management, to depict scenarios of future productivity, and to support redefinition of periods, and areas designated for grazing activities in the mountains.

Monitoring wildlife population trends with sample counts: a case study on the Alpine ibex (Capra ibex)

Monitoring population dynamics is of fundamental importance in conservation but assessing trends in abundance can be costly, especially in large and rough areas. Obtaining trend estimations from counts performed in only a portion of the total area (sample counts) can be a cost‐effective method to improve the monitoring and conservation of species difficult to count.We tested the effectiveness of sample counts in monitoring population trends of wild animals, using as a model population the Alpine ibex Capra ibex in the Gran Paradiso National Park (Italy), both with computer simulations and using historical count data collected over the last 65 years. Despite sample counts failed to correctly estimate the true population abundance, sampling half of the target area could reliably monitor the trend of the target population. In case of strong changes in abundance, an even lower proportion of the total area could be sufficient to identify the direction of the population trend. However, when there is a high yearly trend variability, the required number of samples increases and even counting in the entire area can be ineffective to detect population trends. The effect of other parameters, such as which portion of the area is sampled and detectability, was lower, but these should be tested case by case.Sample counts could therefore constitute a viable alternative to assess population trends, allowing for important, cost‐effective improvements in the monitoring of wild animals of conservation interest.

Age-specific survival of territorial and non-territorial male chamois.

How alternative reproductive tactics (ARTs) are maintained in wildlife populations is one of the major questions in evolutionary biology. As a dominant status, territoriality is typically linked to increased mating opportunities, and one explanation why this behaviour coexists with other tactics is that dominance implies survival costs. Such a trade-off may occur in the Northern chamois Rupicapra rupicapra, as reproductive advantages of territorial males over non-territorial males could be counterbalanced by a reduction in survival mediated through energy expenditure, stress and parasitic infections, ultimately favouring ART coexistence. Here, we analysed age-dependent survival probabilities of territorial (n = 15) and non-territorial (n = 16) adult chamois using information collected over 12 years between 2010 and 2021 in the Gran Paradiso National Park (Western Italian Alps). Survival rates were estimated with a CMR approach using Burnham's joint modelling of live encounter and dead recovery data. The model selection procedure, based on AICc value minimisation, supported a linear decrease of survival with age but the results did not match our predictions, as territorial chamois did not have lower survival rates than non-territorial chamois. In contrast, territorial males appeared to enjoy reproductive success at lower survival costs. This, in turn, supports the role of other factors, such as snow-dependent environmental stochasticity, in the maintenance of ARTs in chamois populations. The limited sample size, however, calls for caution in interpretation, and long-term studies of lifetime reproductive success and survival are necessary to clarify the mechanisms underlying the expression and coexistence of different reproductive behaviours in this species.

Spatial and temporal variability of carbon dioxide fluxes in the Alpine Critical Zone: The case of the Nivolet Plain, Gran Paradiso National Park, Italy.

The dynamics of carbon dioxide fluxes in the high-altitude Alpine Critical Zone is only partially understood. The complex geomorphology induces significant spatial heterogeneity, and a strong interannual variability is present in the often-extreme climatic and environmental conditions of Alpine ecosystems. To explore the relative importance of the spatial and temporal variability of CO2 fluxes, we analysed a set of in-situ measurements obtained during the summers from 2018 to 2021 in four sampling plots, characterised by soils with different underlying bedrock within the same watershed in the Nivolet plain, in the Gran Paradiso National Park, western Italian Alps. Multi-regression models of CO2 emission and uptake were built using measured meteo-climatic and environmental variables considering either individual years (aggregating over plots) or individual plots (aggregating over years). We observed a significant variability of the model parameters across the different years, while such variability was much smaller across different plots. Significant changes between the different years mainly concerned the temperature dependence of respiration (CO2 emission) and the light dependence of photosynthesis (CO2 uptake). These results suggest that spatial upscaling can be obtained from site measurements, but long-term flux monitoring is required to properly capture the temporal variability at interannual scales.

Cumulative Spatial and Temporal Analysis of Anthropogenic Impacts in the Protected Area of the Gran Paradiso National Park in the NW Alps, Italy

Anthropogenic threats are responsible for habitat degradation and biodiversity decline. The mapping of the distribution and intensity of threats to biodiversity can be useful for informing efficient planning in protected areas. In this study, we propose a cumulative spatial and temporal analysis of anthropogenic impacts insisting on an alpine protected area, the Gran Paradiso National Park. The applied methodology starts with the construction of a spatial and temporal dataset of anthropogenic impacts and normalization based on relative intensity. The impacts analyzed include overgrazing, helicopter flights, road networks, built-up areas, worksites, derivations and discharges, sports activities, and dams and hydroelectric power plants. Each impact was assigned a weight based on its temporal persistence. Threats maps obtained from the collected, normalized, and weighted geodata are thus obtained. Finally, the risk map is calculated by combining the impact map with the vulnerability map, estimated through the methodology outlined in the Green Guidelines of the Metropolitan City of Turin. The risk map obtained was cross-referenced with the Park’s cartography to highlight any critical issues to specific habitats. Results show that most of the territory falls in low-risk (63%) or no-risk (35%) areas. However, there are some habitats that are totally or nearly totally affected by some degree of risk, although different to zero, such as the “Lentic waters with aquatic vegetation [incl. cod. 3130]”, the “Lentic waters partially buried”, the “Mountain pine forests (Pinus uncinata) [cod. 9430]”, and the “Mixed hygrophilous woods of broad-leaved trees [incl. cod. 91E0]”. This study highlights both the potential of these analyses, which enable informed management and planning of the fruition of protected areas, and the limitations of such approaches, which require in-depth knowledge of the territory and ecosystems and how they respond to threats in order to refine the model and obtain realistic maps.

Season-dependent impact of forage quality on stress in alpine chamois.

Chronically heightened stress levels in wildlife species may have detrimental effects on individual life history traits, for example, through the increased likelihood of disease, parasitic infections, and overall reduced fitness. Understanding the drivers of stress may thus have great potential for informing wildlife conservation. Although the role of climate and individual status is well studied in stress ecology, the impact of related stressors such as dietary quality is of increasing interest to wildlife research and conservation. In this study, fecal cortisol metabolites (FCMs) in Alpine chamois Rupicapra r. rupicapra used as bioindicators of stress, and their relationship with forage quality-measured as the percentage of fecal crude protein (CP)-were investigated. Data collection took place in 2011 and 2012 in the Gran Paradiso National Park (Western Italian Alps), on 22 individually marked adult males. The relationship between FCMs and CPs was analyzed through linear models and separated between winter and summer months, accounting for the effect of potentially confounding exogenous and endogenous variables. After AICc-based model selection, we found that forage quality was negatively related to FCM levels in Alpine chamois during the summer months, meaning that higher quality forage was associated with the decreased expression of stress hormones. However, during the winter months, we did not find a significant relationship, potentially as a result of forage quality being ubiquitously poor. Although the mechanisms through which dietary variations impact FCM concentrations in wildlife populations are largely unknown, the occurrence of significant relationships between forage quality and stress levels supports potentially important implications for the long-term effect of climatic changes on the fitness of wildlife populations.

Carbon dioxide exchanges in an alpine tundra ecosystem (Gran Paradiso National Park, Italy): A comparison of results from different measurement and modelling approaches

Mountain ecosystems are particularly sensitive to the effects of climate change and require a detailed understanding of how their components respond to the varying environmental conditions. However, the knowledge of crucial biogeochemical variables, such as carbon dioxide (CO2) fluxes in the Critical Zone of high-altitude grassland and Alpine tundra, is still patchy. In this framework, two methods are typically adopted to measure CO2 exchanges between the atmosphere and the underlying ecosystem: eddy covariance and accumulation chambers. Potential drawbacks affect both approaches, also depending on the scale at which studies are performed. On the one hand, eddy covariance method provides large spatial coverage, despite requiring specific statistical assumptions that are not always valid in remote environments. In addition, the eddy covariance method allows measuring only the CO2 net ecosystem exchange (NEE), while the separation of CO2 emission (ecosystem respiration, ER) and uptake (gross primary production, GPP), needed for understanding ecosystem functioning and its possible future changes, requires partitioning procedures based on regressive models. On the other hand, accumulation chambers allow for direct measurements of both NEE and ER but are usually limited to sampling small areas and the chambers themselves could potentially disturb plant-soil dynamics. The present study investigates such issues by combining three complementary methods (i.e., eddy covariance, portable and automated accumulation chambers) to measure summer CO2 fluxes at the soil-vegetation-atmosphere interface in a heavily instrumented high-altitude Alpine tundra site. While eddy covariance and portable chamber measurements provide consistent estimates of the NEE, a significant discrepancy between the results of the different methodologies was found for daytime ER. In particular, the eddy covariance daytime and nighttime partitioning methods failed in representing ER at the ecosystem scale. The discrepancy between modelled and measured ER suggests that different processes are involved during day and night, which are not fully represented in models. These aspects would require further explorations to achieve site-specific assessments of daytime ER.

Main ecological and environmental factors affecting forage yield and quality in alpine summer pastures (NW‐Italy, Gran Paradiso National Park)

AbstractSummer pastures in the European Alps play a crucial role in providing high quality forage for grazing livestock and encompass a wide variety of vegetation communities. The main issue of their management is the optimal exploitation of the available forage in relation to environmental constraints, aiming at obtaining the highest forage yield and quality from each vegetation community. In this work, we monitored six different vegetation communities characterized by contrasting topographic features and species compositions throughout the grazing season for two years. We performed botanical and phenological surveys, climate‐related measurements, and herbage samplings to assess forage quantity and quality (i.e., digestibility and proximate composition, estimated by near‐infrared reflectance spectroscopy). We analysed the influence of climatic, topographic, and vegetation variables on pasture herbage through univariate and multivariate analyses. The cover of wide‐leaf grasses primarily promoted biomass production, which was in turn lowered by increasing elevation and slope. On the other hand, a minor effect on forage yield was observed for an increasing cover of sedges and rushes and mean temperatures. Climatic variables (especially water deficit) and advanced phenological stages were the main degrading factors of forage quality in terms of crude protein and digestibility, while enhancing fibre contents. At increasing cover of legumes, fibre content declined and digestibility increased consequently, while the abundance of other non‐legume forbs played a significant role in lowering fibre content. Multivariate analysis highlighted the differing influence of single plant species on forage features even within the same functional species pool. However, attention should be paid to the toxicity and low palatability of some plants, especially forbs. Eutrophic vegetation communities, rich in wide‐leaf grasses and legumes, could be maintained and enhanced through pastoral management to increase alpine pasture production and quality.

Are protected areas effective in preserving Alpine stream morphology and biodiversity? A field study in the oldest Italian National Park

AbstractGlobal changes and local pressures related to the exploitation of water resources are significantly reducing streams' biodiversity and threatening their ecological balance. This trend concerns both the lowland rivers flowing in densely populated areas and the mountain headwaters, where the effects of global change are dramatically evident and often accompanied by alterations in river hydro‐morphology. From mountains to lowlands, regulation and morphological alterations such as bank reinforcement, water abstractions, dams, and weirs are among the most significant threats for river ecosystems. Protected areas and especially large national parks constitute an effective strategy to face the loss of biodiversity, but little is known about their effectiveness regarding lotic environments. To examine the recent trend in aquatic communities in Alpine protected areas, we carried out biological sampling of benthic communities and hydro‐morphological status assessment in 12 high‐altitude streams within the oldest Italian National Park, that is, the Gran Paradiso National Park, located in the heart of the Western Alps, and we compared results with a previous survey performed in 2005, by keeping the same experimental design. Our results detected minimal changes in the hydro‐morphology of the studied watercourses. Biomonitoring indices associated with benthic communities likewise did not provide evidence of significant differences. Conversely, diatom communities were more uniform in 2020 compared to 2005, and a slight species turnover occurred over the 15‐year interval. Despite this, our findings underline the effectiveness of protected areas for the conservation of running water environments because they limit hydro‐morphological alterations, thus increasing the resilience of aquatic communities to climate change.

How Do People Experience the Alps? Attitudes and Perceptions in Two Protected Areas in Italy

Protected areas play an important role due to their twofold capacity for biodiversity conservation and the provision of many benefits to human well-being. Tourism can be a tool for protecting nature, enhancing people’s sensitivity, and a threat to biodiversity management. This study investigates users’ attitudes and perceptions and managers’ concerns related to the frequentation of two protected areas in the Italian Alps: the Gran Paradiso National Park and the Adamello Regional Park. We carried out 32 semi-structured interviews with park managers and municipalities to identify their perception of tourism and possible threats related to the use of the parks. Thus, we administered questionnaires to 3399 users of the PAs to investigate their attitudes and perceptions. We made considerations on whether there were similarities in the attitudes identified by the park managers and results of the questionnaires. Questionnaires confirmed the managers’ perception of mass tourism regarding one-day stays and the purpose of the visits, but we could not exhaustively confirm the increase of new visitors. We performed a binary logistic regression to understand the relationship between short-term stays and attitudes of visitors (origin, frequency of visits, stakeholders’ category, and biographical data). Eventually, interviews stated an exacerbation of the growth of visitors due to the COVID-19 pandemic; thus, we investigated if the pandemic changed the assiduity of visits, and half of the users claimed a change in their assiduity of visits, but mostly declared a decreased frequentation of the area.

Comparison of Three Different Random Forest Approaches to Retrieve Daily High-Resolution Snow Cover Maps from MODIS and Sentinel-2 in a Mountain Area, Gran Paradiso National Park (NW Alps)

In the Alpine environment, snow plays a key role in many processes involving ecosystems, biogeochemical cycles, and human wellbeing. Due to the inaccessibility of mountain areas and the high spatial and temporal heterogeneity of the snowpack, satellite spatio-temporal data without gaps offer a unique opportunity to monitor snow on a fine scale. In this study, we present a random forest approach within three different workflows to combine MODIS and Sentinel-2 snow products to retrieve daily gap-free snow cover maps at 20 m resolution. The three workflows differ in terms of the type of ingested snow products and, consequently, in the type of random forest used. The required inputs are the MODIS/Terra Snow Cover Daily L3 Global dataset at 500 m and the Sentinel-2 snow dataset at 20 m, automatically retrieved through the recently developed revised-Let It Snow workflow, from which the selected inputs are, alternatively, the Snow Cover Extent (SCE) map or the Normalized Difference Snow Index (NDSI) map, and a Digital Elevation Model (DEM) of consistent resolution with Sentinel-2 imagery. The algorithm is based on two steps, the first to fill the gaps of the MODIS snow dataset and the second to downscale the data and obtain the high resolution daily snow time series. The workflow is applied to a case study in Gran Paradiso National Park. The proposed study represents a first attempt to use the revised-Let It Snow with the purpose of extracting temporal parameters of snow. The validation was achieved by comparison with both an independent dataset of Sentinel-2 to assess the spatial accuracy, including the snowline elevation prediction, and the algorithm’s performance through the different topographic conditions, and with in-situ data collected by meteorological stations, to assess temporal accuracy, with a focus on seasonal snow phenology parameters. Results show that all of the approaches provide robust time series (overall accuracies of A1 = 93.4%, and A2 and A3 = 92.6% against Sentinel-2, and A1 = 93.1%, A2 = 93.7%, and A3 = 93.6% against weather stations), but the first approach requires about one fifth of the computational resources needed for the other two. The proposed workflow is fully automatic and requires input data that are readily and globally available, and promises to be easily reproducible in other study areas to obtain high-resolution daily time series, which is crucial for understanding snow-driven processes at a fine scale, such as vegetation dynamics after snowmelt.

Pasture areas in the Gran Paradiso National Park

ABSTRACT Mountain pastures are essential for maintainig biodiversity and local economies. Despite the great value and fragility of these ecosystems, an up-to-date overview of extent and type of alpine pastures is lacking in many areas of the Alps. In this study, the interpretation of ancillary information combined with expeditious field campaigns, and the harmonization of classification methodologies allowed us to: (1) define the spatial extent of mountain pastures; (2) identify the non-grazeable percentage in these areas; (3) Characterize and map pasture types within the Gran Paradiso National Park (Italy), where 4596 ha of grazeable areas were mapped. Among the 13 categories identified, the three most represented in the park are Bare thermophile grasslands (38%), Nardus swards (20%), and Alpine intermediate grasslands (18%). The maps obtained in this study are useful for animal management during the grazing season, and have the capability of geographically assessing potential forage avaibility through modeling and remote sensing data.

Anti-Inflammatory and Wound Healing Properties of Leaf and Rhizome Extracts from the Medicinal Plant Peucedanum ostruthium (L.) W. D. J. Koch

Peucedanum ostruthium (L.) W. D. J. Koch (Apiaceae) is a worldwide perennial herb native to the mountains of central Southern Europe. The rhizome has a long tradition in popular medicine, while ethnobotanical surveys have revealed local uses of leaves for superficial injuries. To experimentally validate these uses, plant material was collected in the Gran Paradiso National Park, Aosta Valley, Italy, and the rhizome and leaves were micromorphologically and phytochemically characterized. Polyphenol-enriched hydroalcoholic rhizome and leaf extracts, used in cell-free assays, showed strong and concentration-dependent antioxidant and anti-inflammatory activities. In vitro tests revealed cyclooxygenase and lipoxygenase inhibition by the leaf extract, while the rhizome extract induced only lipoxygenase inhibition. MTT assays on HaCaT keratinocytes and L929 fibroblasts showed low cytotoxicity of extracts. In vitro scratch wound test on HaCaT resulted in a strong induction of wound closure with the leaf extract, while the effect of the rhizome extract was lower. The same test on L929 cells showed similar wound closure induction with both extracts. The results confirmed the traditional medicinal uses of the rhizome as an anti-inflammatory and wound healing remedy for superficial injuries but also highlighted that the leaves can be exploited for these purposes with equal or superior effectiveness.

Alpine forests are a suitable habitat for the Hazel Dormouse

The Hazel Dormouse (Muscardinus avellanarius) is commonly considered a typical lowland species, occasionally observed at higher elevations in mountain habitats. This study began with preliminary investigations in the Gran Paradiso National Park in the Western Alps, where nests of Hazel Dormice were observed at around 2000 m a.s.l. In 2019, a mark-recapture project started in two valleys (Valsavarenche and Val di Rhêmes), positioning six grids with 40 nest boxes from 1000 m to 2000 m a.s.l. to investigate the ecology and adaptations of dormouse populations along the altitudinal gradient. In these years, nest boxes were checked irregularly, and the number of marked animals was low. The number of individuals captured in the highest grids at 2000 m increased from 1 to 8 in Valsavarenche and from 11 to 15 in Val di Rhêmes. These results seem to confirm a continuous presence of the species at the upper edge of the forest vegetation. The data from Valsavarenche suggest some significant population fluctuations, but the effect of nest boxes on population densities cannot be excluded.

Distribution of Glirids in an Alpine national park

In this long-term study, we evaluated the distribution of three species of Glirids: Hazel Dormouse (Muscardinus avellanarius), Garden Dormouse (Eliomys quercinus) and Edible Dormouse (Glis glis) in the Gran Paradiso National Park (Western Italian Alps). The aim was to investigate the ecology, adaptation strategies, and distribution of these dormouse populations along an altitudinal gradient. Monitoring started in 2015 and is still ongoing. We used five different techniques (searching for nests, grids of nest boxes, transects of live traps, nesting tubes, and footprint tunnels), placed along an altitudinal gradient from 700 to 2300 m a.s.l. We found a total of 680 signs of the presence of Hazel Dormouse and 46 individuals, 275 signs and 142 individuals of the Garden Dormouse and 674 signs and 67 individuals of the Edible Dormouse. The three species selected different altitudinal gradients: Edible Dormouse from 800 to 1700 m, with a prevalence between 800-1100 m; Garden Dormouse from 1100 to 2000 m, with a prevalence between 1400-1700 m. The Hazel Dormouse was ubiquitous from 800 to 2032 m, without a clear altitudinal pattern. Edible Dormice were mainly found in deciduous and mixed forests, while Garden Dormice usually occurred in coniferous forests. The Hazel Dormouse seemed to be regularly distributed in all forest types up to the tree limit. These results, obtained from diverse methodologies, permitted comparison between the monitoring protocols, improved knowledge of habitat selection by Glirids in Alpine habitats, as well as providing novel insights within the context of climate change.

Distribution Drivers of the Alien Butterfly Geranium Bronze (Cacyreus marshalli) in an Alpine Protected Area and Indications for an Effective Management.

Simple SummaryCacyreus marshalli is strictly dependent on its host plant (Pelargonium spp.), which is widely cultivated as an ornamental plant in mountain areas. An experiment demonstrated that the butterfly is able to develop on some wild geraniums, too, making mountain areas highly at risk for a potential expansion to natural habitats. We therefore decided to carry out research in a protected mountain area (Gran Paradiso National Park), focusing on the drivers which determine the distribution of C. marshalli using data provided by either an opportunistic approach or a rigorous survey protocol. The data collected via the planned survey were more informative than the opportunistic observations, which were few and narrow. We suggest investing more in citizen science projects and combining them with a designed protocol according to an integrated approach. We observed that C. marshalli distribution is strictly linked to host plant availability but is constrained by cold temperatures, although Pelargonium spp. are abundant. The temperature increase scenario showed an increase of butterfly abundance, but halving of the host plant population could drive the rate of infestation to return to what it was previously, excluding a countertrend in some high-altitude sites. It is therefore important to test management actions designed to control alien species before implementing them.Cacyreus marshalli is the only alien butterfly in Europe. It has recently spread in the Gran Paradiso National Park (GPNP), where it could potentially compete with native geranium-consuming butterflies. Our study aimed to (1) assess the main drivers of its distribution, (2) evaluate the potential species distribution in GPNP and (3) predict different scenarios to understand the impact of climate warming and the effect of possible mitigations. Considering different sampling designs (opportunistic and standardised) and different statistical approaches (MaxEnt and N-mixture models), we built up models predicting habitat suitability and egg abundance for the alien species, testing covariates as bioclimatic variables, food plant (Pelargonium spp.) distribution and land cover. A standardised approach resulted in more informative data collection due to the survey design adopted. Opportunistic data could be potentially informative but a major investment in citizen science projects would be needed. Both approaches showed that C. marshalli is associated with its host plant distribution and therefore confined in urban areas. Its expansion is controlled by cold temperatures which, even if the host plant is abundant, constrain the number of eggs. Rising temperatures could lead to an increase in the number of eggs laid, but the halving of Pelargonium spp. populations would mostly mitigate the trend, with a slight countertrend at high elevations.