Gianluca Filippa

Environmental Protection Agency of Aosta Valley | ARPA · Section of Physical Agents - Climate change unit

Over the last century, the management of pastoral systems has undergone major changes to meet the livelihood needs of alpine communities. Faced with the changes induced by recent global warming, the ecological status of many pastoral systems has seriously deteriorated in the western alpine region. We assessed changes in pasture dynamics by integrat...

This article presents the structure and results of a simplified model (VISTOCK) for simulating grass growth and water dynamics of grassland systems. The model, based on a process-based approach coupled with proximal (SKR 1800 2-Channel Light Sensor) and remote (Sentinel-2) NDVI-derived data for estimating LAI, simulates aboveground biomass (AGB), n...

The use of very long spatial datasets from satellites has opened up numerous opportunities, including the monitoring of vegetation phenology over the course of time. Considering the importance of grassland systems and the influence of climate change on their phenology, the specific objectives of this study are: (a) to identify a methodology for a r...

Glacier forefields have long provided ecologists with a model to study patterns of plant succession following glacier retreat. While plant survey-based approaches applied along chronosequences provide invaluable information on plant communities, the “space-for-time” approach assumes environmental uniformity and equal ecological potential across sit...

Glacier forefields have long provided ecologists with a model to study patterns of plant succession following glacier retreat. While plant survey-based approaches applied along chronosequences provide invaluable information on plant communities, the “space-for-time” approach assumes environmental uniformity and equal ecological potential across sit...

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 h...

Remote sensing capabilities to monitor evergreen broadleaved vegetation are limited by the low temporal variability in the greenness signal. With canopy greenness computed from digital repeat photography (PhenoCam), we investigated how canopy greenness related to seasonal changes in leaf age and traits as well as variation of trees’ water fluxes (c...

Il “patterned ground” (suoli strutturati periglaciali) rappresenta uno straordinario paesaggio degli ambienti freddi, dominati dall’azione di gelo e disgelo, con o senza permafrost. Sulle Alpi, tale fenomeno è visibile in località esposte ai venti invernali, che, rimuovendo la neve, ne limitano l’azione di coibentazione, favorendo la penetrazione d...

Satellite‐derived vegetation indices (VIs) provide a way to analyse vegetation phenology over decades globally. However, these data are often contaminated by different kinds of optical noise (e.g., cloud, cloud shadow, snow, aerosol), making accurate phenology extraction challenging. We present an open‐source state‐of‐the‐art R package called pheno...

Climate change is expected to increase both the frequency and the intensity of climate extremes, consequently increasing the risk of forest role transition from carbon sequestration to carbon emission. These changes are occurring more rapidly in the Alps, with important consequences for tree species adapted to strong climate seasonality and short g...

Mountain grazing lands are key constituents of the natural, economical and cultural heritage, but at the same time sensitive to climate and land use change, hence requiring urgent adaptation and management strategies. These must be based on a better understanding of the distribution of mountain pastoral resources across space and time. In this stud...

Monitoring forest responses to climate-smart forestry (CSF) is necessary to determine whether forest management is on track to contribute to the reduction and/or removal of greenhouse gas emissions and the development of resilient mountain forests. A set of indicators to assess "the smartness" of forests has been previously identified by combining...

The leaf economics spectrum1,2 and the global spectrum of plant forms and functions³ revealed fundamental axes of variation in plant traits, which represent different ecological strategies that are shaped by the evolutionary development of plant species². Ecosystem functions depend on environmental conditions and the traits of species that comprise...

The long-term increase in satellite-based proxies of vegetation cover is a well-documented response of seasonally snow-covered ecosystems to climate warming. However, observed greening trends are far from uniform, and substantial uncertainty remains concerning the underlying causes of this spatial variability. Here, we processed surface reflectance...

Precipitation orographic enhancement is the result of both synoptic circulation and topography. Since high-elevation headwaters are often sparsely instrumented, the magnitude and distribution of this enhancement, as well as how they affect precipitation lapse rates, remain poorly understood. Filling this knowledge gap would allow a significant step...

Woody species encroachment on grassland ecosystems is occurring worldwide with both negative and positive consequences for biodiversity conservation and ecosystem services. Remote sensing and image analysis represent useful tools for the monitoring of this process. In this paper, we aimed at evaluating quantitatively the potential of using high-res...

p>The following authors were omitted from the original version of this Data Descriptor: Markus Reichstein and Nicolas Vuichard. Both contributed to the code development and N. Vuichard contributed to the processing of the ERA-Interim data downscaling. Furthermore, the contribution of the co-author Frank Tiedemann was re-evaluated relative to the co...

The base phenopix package vignette provides a tutorial for basic processing of digital images in the context of vegetation phenology. Fell free to comment on the vignette and on the package or directly email me.

Precipitation orographic enhancement depends on both synoptic circulation and topography. Since high-elevation headwaters are often sparsely instrumented, the magnitude and distribution of this enhancement remain poorly understood. Filling this knowledge gap would allow a significant step ahead for hydrologic-forecasting procedures and water manage...

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their...

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their...

Anthropogenic nitrogen (N) deposition and resulting differences in ecosystem N and phosphorus (P) ratios are expected to impact photosynthetic capacity, i.e. maximum gross primary productivity (GPPmax). However, the interplay between N and P availability with other critical resources on seasonal dynamics of ecosystem productivity remain largely unk...

Il riscaldamento globale ha impatti enormi sugli ecosistemi alpini. Uno tra gli effetti più evidenti è il ritiro dei ghiacciai, a partire dalla fine della Piccola Età Glaciale (1860 circa), che ha provocato l'esposizione di ampie superfici precedentemen-te coperte dai ghiacciai. Queste superfici sono dei laboratori naturali per la verifica delle te...

Review of the existing bibliography shows that the direction and magnitude of the long-term trends of UV irradiance, and their main drivers, vary significantly throughout Europe. Analysis of total ozone and spectral UV data recorded at four European stations during 1996-2017 reveals that long-term changes in UV are mainly driven by changes in aeros...

Review of the existing bibliography shows that the direction and magnitude of the long-term trends of UV irradiance, and their main drivers, vary significantly throughout Europe. Analysis of total ozone and spectral UV data recorded at four European stations during 1996 – 2017 reveals that long-term changes in UV are mainly driven by changes in aer...

Since the 1980s, vegetated lands have experienced widespread greening at the global scale. Numerous studies have focused on spatial patterns and mechanisms of this phenomenon, especially in the Arctic and sub-Arctic regions. Greening trends in the European Alps have received less attention, although this region has experienced strong climate and la...

We investigate the main drivers of the variability of the solar spectral UV irradiance at two Italian sites located at quite different latitude, altitude and environmental context: Aosta-Saint Christophe and Rome. Comparison between the spectral UV measurements at the two sites, with respect to other atmospheric parameters, allows us to identify ho...

The input of mineral dust from arid regions impacts snow optical properties. The induced albedo reduction generally alters the melting dynamics of the snowpack, resulting in earlier snowmelt. In this paper, we evaluate the impact of dust depositions on the melting dynamics of snowpack at a high-elevation site (2160 m) in the European Alps (Torgnon,...

The authors modify the schematic plots in their article [...]

Aims Grasslands are among the largest ecosystems in the world and store up to 30% of the global reserves of carbon. Decomposition processes have a crucial role in maintaining carbon balance, but few studies have investigated the heterogeneity of this process at small scale, especially in alpine ecosystems. We aimed at investigating the interactions...

The presence or absence of leaves within plant canopies exert a strong influence on the carbon, water and energy balance of ecosystems. Identifying key changes in the timing of leaf elongation and senescence during the year can help to understand the sensitivity of different plant functional types to changes in temperature. When recorded over many...

Research infrastructures play a key role in launching a new generation of integrated long-term, geographically distributed observation programmes designed to monitor climate change, better understand its impacts on global ecosystems, and evaluate possible mitigation and adaptation strategies. The pan-European Integrated Carbon Observation System co...

The input of mineral dust from arid regions impacts snow optical properties. The induced albedo reduction generally alters the melting dynamics of the snowpack, resulting in earlier snowmelt. In this paper, we evaluate the impact of dust depositions on the melting dynamics of snowpack in a high-altitude site (2160m) in the European Alps (Torgnon, A...

Tree-grass ecosystems are widely distributed. However, their phenology has not yet been fully characterized. The technique of repeated digital photographs for plant phenology monitoring (hereafter referred as PhenoCam) provide opportunities for long-term monitoring of plant phenology, and extracting phenological transition dates (PTDs, e.g., start...

Measuring ecosystem CO2 fluxes is of foremost importance to quantify and model the global carbon cycle, and a core objective of flux networks, such as FLUXNET and ICOS, is to improve the measurement standards. However, over the years, cold sites have presented challenges to the flux community in understanding/quantifying land-surface interactions:...

Climate extremes can have tremendous impacts on the terrestrial biosphere and their frequency is very likely going to increase in the coming years. In this study we examine the impact of the 2015 summer heat wave on a mountain grassland in the Western European Alps by jointly analyzing phenocam greenness (GCC) trajectories, proximal sensing, CO2 fl...

Time series of vegetation indices (e.g. normalized difference vegetation index [NDVI]) and color indices (e.g. green chromatic coordinate [GCC]) based on radiometric measurements are now available at different spatial and temporal scales ranging from weekly satellite observations to sub-hourly in situ measurements by means of near-surface remote se...

Net ecosystem carbon dioxide (CO2) exchange (NEE) at FLUXNET sites is typically evaluated by means of the eddy covariance technique using a set of instruments on a single tower. However, in complex terrain, such as mountain areas, and during nighttime atmospheric conditions, with low turbulent mixing and stable stratification, this approach is know...

The Mediterranean-type oak/grass savanna of California is composed of widely spaced oak trees with understory grasses. These savanna regions are interspersed with large areas of more open grasslands. The ability of remotely sensed data (with various spatial resolutions) to monitor the phenology in these water-limited oak/grass savannas and open gra...

Automated canopy-level optical sampling in tandem with ecosystem-atmosphere flux observations is continuously carried on at a variety of ecosystems through the Specnet network (http://specnet.info/). Specifically, 9 sites within US and Europe were selected since 2015, to investigate the use of novel NDVI and PRI low-cost sensors for the analysis of...

The seasonal input of mineral dust from Saharan desert impacts the optical properties of snow in the European Alps. The albedo reduction may alter the melting dynamics of the snowpack, resulting in earlier snow melts. In this contribution, we evaluate the impact of dust depositions on snowpack melting dynamics in a high-altitude site (2160 m) in th...

Digital repeat photography is an invaluable tool for phenological studies. Here we used a recently developed method to calculate NDVI from near-infrared (NIR) enabled digital cameras (NDVIC) at 17 sites (for a total of 74 year-sites) encompassing six plant functional types (PFT) from the PhenoCam network.

In molte catene montuose delle medie latitudini sono stati descritti siti ”freddi” sotto al limite del permafrost discontinuo montano, localizzati prevalentemente alla base di versanti detritici e in depressioni carsiche (doline). In questi ambienti, si può osservare la presenza di permafrost localizzato anche se la temperatura media annua dell’ari...

Plant phenology is recognized as important for ecological dynamics. There has been a recent advent of phenology and camera networks worldwide. The established PhenoCam Network has sites in the United States, including the western states. However, there is a paucity of published research from semi-arid regions. In this study, we demonstrate the util...

In alpine environments, the growing season is severely constrained by low temperature and snow. Here, we aim at determining the climatic factors that best explain the interannual variation in spring growth onset of alpine plants, and at examining whether photoperiod might limit their phe- nological response during exceptionally warm springs and ear...

Earth hummocks are small cryogenic mounds, covered by grass, closely spaced in grassland or wetlands. Hummock microtopography establishes specific microclimatic conditions, with small-scale variations in soil thermal properties and water regimes, which influence biogeochemical cycles. These properties, coupled with different litter decomposability,...

The spatial phenopix package vignette provides a tutorial for pixel-by-pixel processing of digital images in the context of vegetation phenology. Fell free to comment on the vignette and on the package or directly email me. After being out of date for quite some time, now the vignette is updated according to the current package version. Enjoy!

n this paper we extensively describe new software available as a R package that allows for the extraction of phenological information from time-lapse digital photography of vegetation cover. The phenopix R package includes all steps in data processing. It enables the user to: draw a region of interest (ROI) on an image; extract red green and blue d...

Grasslands show a variable degree of biodiversity essentially due to climate and management practices. In turn, grassland biodiversity translates into spatial variability of species distribution, and these species are likely characterized by a different phenology. We hypothesize that by quantifying the spatial variability of grassland phenology we...

Earth hummocks are small cryogenic mounds closely spaced in grassland or wetlands. The microtopography of hummocky terrain establish specific microclimatic conditions which may cause variations on soil chemico-physical properties and a selective distribution of plant species. The work has been carried out at the LTER site of Torgnon (Aosta Valley,...

Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious,...

Mountain ecosystems are generally characterized by complex topography, where the presence of microhabitats and related differences in soil characteristics and snow dynamics induce patches with uneven distribution of species of different plant functional types. In subalpine and alpine grasslands where the growing season is generally limited to 3-4 m...

Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious,...

The increasingly important effect of climate change and extremes on alpine phenology highlights the need to establish accurate monitoring methods to track inter-annual variation (IAV) and long-term trends in plant phenology. We evaluated four different indices of phenological development (two for plant productivity, i.e., green biomass and leaf are...

Plant phenology is a globally recognized indicator of the effects of climate change on the terrestrial biosphere. Accordingly, new tools to automatically track the seasonal development of a vegetation cover are becoming available and more and more deployed. Among them, near-continuous digital images are being collected in several networks in the US...