In-situ Temperature Stations Elucidate Species’ Phenological Responses to Climate in the Alps, but Meteorological and Snow Reanalysis Facilitates Broad Scale and Long-Term Studies

Linking climate variability and change to the phenological response of species is particularly challenging in the context of mountainous terrain. In these environments, elevation and topography lead to a diversity of bioclimatic conditions at fine scales affecting species distribution and phenology. In order to quantify in situ climate conditions for mountain plants, the CREA (Research Center for Alpine Ecosystems) installed 82 temperature stations throughout the southwestern Alps, at different elevations and aspects. Dataloggers at each station provide local measurements of temperature at four heights (5 cm below the soil surface, at the soil surface, 30 cm above the soil surface, and 2 m above ground). Given the significant amount of effort required for station installation and maintenance, we tested whether meteorological data based on the S2M reanalysis could be used instead of station data. Comparison of the two datasets showed that some climate indices, including snow melt-out date and a heat wave index, can vary significantly according to data origin. More general indices such as daily temperature averages were more consistent across datasets, while threshold-based temperature indices showed somewhat lower agreement. Over a 12 year period, the phenological responses of four mountain tree species (ash (Fraxinus excelsior), spruce (Picea abies), hazel (Corylus avellana), birch (Betula pendula)), coal tits (Periparus ater) and common frogs (Rana temporaria) to climate variability were better explained, from both a statistical and ecological standpoint, by indices derived from field stations. Reanalysis data out-performed station data, however, for predicting larch (Larix decidua) budburst date. Overall, our study indicates that the choice of dataset for phenological monitoring ultimately depends on target bioclimatic variables and species, and also on the spatial and temporal scale of the study

Distribution and status of the Ethiopian population of the Chough Pyrrhocorax pyrrhocorax baileyi

Volume: 118Start Page: 101End Page: 10

Stratégies d'exploitation des ressources en fonction du sexe et de la saison chez une espèce grégaire, le chocard à bec jaune (Pyrrhocorax graculus)

The fréquentation of a clumped food resource by a foraging flock of a social corvid species, the Alpine Chough Pyrrhocorax graculus was studied between November 1990 and May 1991 at a refuse tip according to sex and season. Site fréquentation, interactions and success rates were shown to vary with sex and season. Females were less aggressive than males, their success rate was lower, and they principally used low bird density areas where interaction rates were low. Female attendance increased in spring in parallel to their interaction success rate. Among females, those whose weight exceeded the median value were most frequently seen, especially in the area where highest interaction rates were observed. This suggests that alpine choughs use different foraging strategies in order to exploit clumped resources according to their social status (i.e. sex, physical caracteristics) and season.Delestrade Anne. Stratégies d'exploitation des ressources en fonction du sexe et de la saison chez une espèce grégaire, le chocard à bec jaune (Pyrrhocorax graculus). In: Revue d'Écologie (La Terre et La Vie), tome 48, n°2, 1993. pp. 199-206

Impact of climatic change on alpine ecosystems: inference and prediction

Alpine ecosystems will be greatly impacted by climatic change, but other factors, such as land use and invasive species, are likely to play an important role too. Climate can influence ecosystems at several levels. We describe some of them, stressing methodological approaches and available data. Climate can modify species phenology, such as flowering date of plants and hatching date in insects. It can also change directly population demography (survival, reproduction, dispersal), and therefore species distribution. Finally it can effect interactions among species – snow cover for example can affect the success of some predators. One characteristic of alpine ecosystems is the presence of snow cover, but surprisingly the role played by snow is relatively poorly known, mainly for logistical reasons. Even if we have made important progress regarding the development of predictive models, particularly so for distribution of alpine plants, we still need to set up observational and experimental networks which properly take into account the variability of alpine ecosystems and of their interactions with climate

Impact des changements climatiques sur les écosystèmes alpins : comment les mettre en évidence et les prévoir ?

Les écosystèmes alpins vont être grandement influencés par les changements climatiques à venir, mais d’autres facteurs, tels que l’utilisation des terres ou les espèces invasives, pourront aussi jouer un rôle important. Le climat peut influencer les écosystèmes à différents niveaux, et nous en décrivons certains, en mettant l’accent sur les méthodes utilisées et les données disponibles. Le climat peut d’abord modifier la phénologie des espèces, comme la date de floraison des plantes ou la date d’éclosion des insectes. Il peut ensuite affecter directement la démographie des espèces (survie, reproduction, dispersion) et donc à terme leur répartition. Il peut enfin agir sur les interactions entre espèces – le couvert neigeux par exemple modifie le succès de certains prédateurs. Une caractéristique des écosystèmes alpins est la présence d’un manteau neigeux important et pourtant l’influence de la neige reste relativement mal connue, en particulier pour des raisons logistiques. Même si nous avons fait des progrès importants dans le développement de modèles prédictifs, surtout pour ce qui est de la répartition des plantes alpines, il reste à mettre en place des réseaux d’observations et d’expériences permettant de mieux tenir compte de la variabilité des écosystèmes alpins et des interactions avec le climat.<br>Alpine ecosystems will be greatly impacted by climatic change, but other factors, such as land use and invasive species, are likely to play an important role too. Climate can influence ecosystems at several levels. We describe some of them, stressing methodological approaches and available data. Climate can modify species phenology, such as flowering date of plants and hatching date in insects. It can also change directly population demography (survival, reproduction, dispersal), and therefore species distribution. Finally it can effect interactions among species –snow cover for example can affect the success of some predators. One characteristic of alpine ecosystems is the presence of snow cover, but surprisingly the role played by snow is relatively poorly known, mainly for logistical reasons. Even if we have made important progress regarding the development of predictive models, particularly so for distribution of alpine plants, we still need to set up observational and experimental networks which properly take into account the variability of alpine ecosystems and of their interactions with climate

Comparison of budburst phenology trends and precision among participants in a citizen science program

Quantifying shifts in plant phenology in response to climate change represents an ongoing challenge, particularly in mountain ecosystems. Because climate change and phenological responses vary in space and time, we need long-term observations collected at a broad spatial scale. While data collection by volunteers is a promising approach to achieve this goal, one major concern with citizen science programs is the quality and reliability of data. Using a citizen science program (Phenoclim) carried out in the western European Alps, the goals of this study were to analyze (1) factors influencing participant retention rates, (2) the efficacy of a citizen science program for detecting temporal changes in the phenology of mountain trees, (3) differences in budburst date trends among different observer categories, and (4) the precision of trends quantified by different categories of participants. We used 12years of annual tree phenology measurements recorded by volunteers (schools and private individuals) and professionals within the Phenoclim program. We found decadal-scale shifts in budburst date consistent with the results from other studies, including significant advances in budburst date for the common birch and European ash (-4.0 and -6.5days per decade respectively). In addition, for three of six species, volunteers and professionals detected consistent directional trends. Finally, we show how differences in precision among the categories of participants are determined by the number of years of participation in the program, the number of sites surveyed, and the variability in trends among sites. Overall, our results suggest that participants with a wide range of backgrounds are capable of collecting data that can significantly contribute to the study of the impacts of climate change on mountain plant phenology