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Variable decline of Alpine Rock Ptarmigan (Lagopus muta helvetica) in Switzerland between regions and sites
Abstract
Alpine species adapted to mountain climate are particularly vulnerable to environmental changes and have recently come under multiple environmental pressures, such as climate change associated with habitat loss (e.g. upward shift of the treeline) and unfavourable weather, as well as increasing human recreation activities. A prime example is the Alpine Rock Ptarmigan (Lagopus muta helvetica), a subspecies restricted to the Alps. We analysed counts of territorial males from 40 sites in the Swiss Alps since 1995 with state-space models including various environmental variables. Over the 18 study years, population growth rate (as deduced from territorial males) was negative overall (−13 %), but varied greatly between different regions of the Swiss Alps (from −50 to +6 %) and between sites, with some declining drastically and others doing well. Overall and within regions, growth rates showed little evidence for synchrony between local study sites. We did not find an overall factor which explained variation in population growth rates, except for a curvilinear effect of July temperature. It thus seems that various factors act locally to different degrees, such as upward shift of the treeline, unfavourable weather, and perhaps local increase in winter and/or summer tourism and unsustainable hunting. Together with a predicted shrinkage of the distribution area in the future due to global warming, the observed decrease of this isolated subspecies is of conservation concern. A better understanding of the different causes of decline and possibly different management strategies will be essential for the conservation of Alpine Rock Ptarmigan in Switzerland.
Supplementary resource (1)
Data
January 2016
... Revermann et al. (2012) showed that climate was a major factor explaining the distribution of the species in Switzerland, highlighting Ptarmigan as one of the most vulnerable species to climate change in the Alps. Indeed, Pernollet et al. (2015) have shown a substantial increase in the species' elevational distribution in southern and eastern Switzerland across 29 years, and Furrer et al. (2016) identified a decrease of 13% from 1995 to 2013 in Swiss Ptarmigan populations. As a result, the Ptarmigan is classified as a nearthreatened species in Switzerland (Knaus et al. 2021). ...
... To track Ptarmigan populations in the Swiss Alps, yearly point counts have been carried out since 1995 in approximately 40 study areas (Furrer et al. 2016). Depending on the size and topography of the areas, surveys are performed on one or several points that remain the same across the years (Bossert 1977). ...
... It is expected that breeding events such as hatching would be synchronized with optimal foraging conditions (Perrins et al. 1970, Verboven & Visser 1998, Furrer et al. 2016. Indeed, the development of Ptarmigan chicks is intricately linked to the abundance of invertebrates as a high protein resource at specific times of the year (Theberge & West 1973, Savory 1989. ...
Monitoring vulnerable species inhabiting mountain environments is crucial to track population trends and prioritize conservation efforts. However, the challenging nature of these remote areas poses difficulties in implementing effective and consistent monitoring programmes. To address these challenges, we examined the potential of passive acoustic monitoring of a cryptic high mountain bird species, the Rock Ptarmigan Lagopus muta . For 5 months in each of two consecutive years, we deployed 38 autonomous recording units in 10 areas of the Swiss Alps where the species is monitored by a national count monitoring programme. Once the recordings were collected, we built a machine‐learning algorithm to automate call recognition. We focused on studying the species' daily and seasonal calling phenology and relating these to meteorological and climatic data. Rock Ptarmigans were vocally active from March to July, with a peak of activity occurring between mid‐March and late April, 1 or 2 months earlier than the second half of May when the counts of the monitoring programme take place. The calling rate peaked at dawn before dropping rapidly until sunrise. Daily vocal activity demonstrated a consistent association with weather conditions and moon phase, whereas the timing of seasonal vocal activity varied with temperature and snow conditions. We found that the peak of vocal activity occurred when the snowpack was still thick and snow cover was close to 100% but with a local peak of high temperatures. Between our two study years, the peak of vocal activity occurred 30 days later in the colder year, suggesting phenological plasticity in relation to environmental conditions. Passive acoustic monitoring has the potential to complement conventional acoustic counts of cryptic birds by highlighting periods of higher detectability of individuals, and to survey small populations that often remain undetected during single visits. Moreover, our study supports the idea that passive acoustic monitoring can provide valuable data over large spatial and temporal scales, allowing decryption of hidden ecological patterns and assisting in conservation efforts.
... Global warming in the Alps has been particularly evident and is expected to continue at a rapid pace (Gobiet et al., 2014), threatening alpine habitats (Malfasi & Cannone, 2020;Schwager & Berg, 2019). Many high-elevation species are expected to contract their range toward higher elevations in the Alpine region, and notable shifts or contractions have already been reported (Furrer et al., 2016;Pernollet et al., 2015;Scridel et al., 2017). ...
... Our target species are mountain specialists and/or coldadapted species that commonly breed across the Alps (and in at least one other mountain region of Central or Southern Europe) and have been reported to be already or potentially affected by climate change in the Alpine region Chamberlain et al., 2013;Furrer et al., 2016;Imperio et al., 2013;Revermann et al., 2012). They are thus highly suitable candidates for assessing potential impacts of climate modification and identifying climate refugia. ...
... Nevertheless, a rather alarming perspective on future conditions emerged for all four species, with the partial exception of the water pipit. Such an unfavorable outlook is coherent with previous similar studies (e.g., Brambilla et al., 2016Brambilla et al., , 2017de Gabriel Hernando et al., 2021;Furrer et al., 2016;Hotta et al., 2019;Schai-Braun et al., 2021;Scridel et al., 2021) and with the observed and likely still ongoing range contractions or shifts of many coldadapted species in, e.g., Italy and Switzerland (Knaus et al., 2018), as well as throughout most of Europe (Keller et al., 2020). Together with high elevation avian taxa, other species and entire habitats sharing the same ecological space are at high risk due to climate change and its indirect effects. ...
Identifying climate refugia is key to effective biodiversity conservation under a changing climate, especially for mountain‐specialist species adapted to cold conditions and highly threatened by climate warming. We combined species distribution models (SDMs) with climate forecasts to identify climate refugia for high‐elevation bird species (Lagopus muta, Anthus spinoletta, Prunella collaris, Montifringilla nivalis) in the European Alps, where the ecological effects of climate changes are particularly evident and predicted to intensify. We considered future (2041–2070) conditions (SSP585 scenario, four climate models) and identified three types of refugia: (1) in‐situ refugia potentially suitable under both current and future climate conditions, ex‐situ refugia suitable (2) only in the future according to all future conditions, or (3) under at least three out of four future conditions. SDMs were based on a very large, high‐resolution occurrence dataset (2901–12,601 independent records for each species) collected by citizen scientists. SDMs were fitted using different algorithms, balancing statistical accuracy, ecological realism and predictive/extrapolation ability. We selected the most reliable ones based on consistency between training and testing data and extrapolation over distant areas. Future predictions revealed that all species (with the partial exception of A. spinoletta) will undergo a range contraction towards higher elevations, losing 17%–59% of their current range (larger losses in L. muta). We identified ~15,000 km2 of the Alpine region as in‐situ refugia for at least three species, of which 44% are currently designated as protected areas (PAs; 18%–66% among countries). Our findings highlight the usefulness of spatially accurate data collected by citizen scientists, and the importance of model testing by extrapolating over independent areas. Climate refugia, which are only partly included within the current PAs system, should be priority sites for the conservation of Alpine high‐elevation species and habitats, where habitat degradation/alteration by human activities should be prevented to ensure future suitability for alpine species. By combining distribution models (based on a large, high‐resolution dataset, and balancing statistical accuracy, ecological realism, and predictive/extrapolation ability) with climate forecasts, this study identified climate refugia for high‐elevation bird species (Lagopus muta, Anthus spinoletta, Prunella collaris, Montifringilla nivalis) in the European Alps, considering both in‐situ refugia (suitable now and in the future) and ex‐situ refugia (suitable only in the future). Most species will undergo a marked contraction towards higher elevations. In‐situ refugia for at least three species cover ~15,000 km2 of the Alpine region (44% included within protected areas) and represent priority sites for the conservation of high‐elevation species and habitats.
... We analysed population trends using state-space models (Buckland et al., 2004;de Valpine et al., 2002;Dennis et al., 2006) within the Bayesian framework (Kéry & Schaub, 2012), based on the work of Furrer et al. (2016) on the rock ptarmigan. This type of model allowed us to separate the dynamics of the state over time (the abundance) from the observation process (the counts). ...
... Other studies on different species of grouse have observed similar strong spatial heterogeneity of population growth rates even among close populations (Cattadori & Hudson, 1999;Martinoli, 2016). For example, a recent study on rock ptarmigan in the Swiss Alps found similar spatially heterogonous trends with no synchrony between populations (Furrer et al., 2016). Such strong spatial heterogeneity in population growth rates might be explained by the significant differences in local conditions even over short distances in mountains, which might overcome synchronizing drivers expected from large-scale climate patterns (Bjørnstad, 1999;Brambilla et al., 2019;Paradis et al., 2000). ...
Aim
Mountains host complex ecosystems whose wide range of ecological conditions over small geographical distances makes them biodiversity hotspots. To ensure their long‐term conservation, a better understanding of the interaction between climate change and modifications in land use is necessary. Most studies have focused on only one of these factors at a time, leading to incomplete predictions. In this study, we explored the relative contribution of both recreative activities and climate change on the population dynamics of the black grouse (Tetrao tetrix), an emblematic cold‐adapted species of the Alps.
Methods
We used data from a network of 47 monitoring sites dispersed around the French Alps and surveyed since the 1980s or 1990s. We estimated black grouse population growth rates using state‐space models and tested for effects of biotic and abiotic pressures on both long‐term trends and inter‐annual variations in these rates.
Results
Population trajectories were strongly heterogeneous in space; nevertheless, a general decline at the edge of the black grouse distribution area was revealed in the southern pre‐Alps. We found very little influence of hunting and new ski lift cables installation on inter‐annual variability in population growth rate. In contrast, our results suggest strong impact of climatic conditions and phenology. While temperature positively influenced growth rate, precipitation had a negative effect. Early snowmelt and vegetation season were correlated with high positive values of annual population growth rates.
Main conclusions
Birds in mountain habitats may be drastically affected by ongoing climate change, perhaps to a greater extent than by an increase in recreational activities. However, other human activities in the mountains (such as animal grazing or forest exploitation) that were not taken into consideration in this study might also have a strong impact on habitat structure and indirectly affect populations’ growth.
... We analysed population trends using state-space models Dennis et al., 2006) within the Bayesian framework , based on the work of Furrer et al. (2016) on the rock ptarmigan. This type of model allowed us to separate the dynamics of the state over time (the abundance) from the observation process (the counts). ...
... Based on this premises, we modelled counts and bags as independent states, conditional on independent observation processes, sharing the same stochastic population growth rates. We followed the approach described by Furrer et al. (2016), adapting it to the specific purpose of our study. ...
Mountains are reservoirs of biodiversity whose strong altitudinal gradients over short distances are associated with strong spatial heterogeneity of local environmental conditions. While biodiversity has so far been rather well preserved in mountains due to poor accessibility, predictions of ongoing climate change suggest even more rapid and marked effects in mountains than in plains. My main objective is to understand how global change are impacting the population dynamics of mountain galliformes. My work has shown (1) a strong heterogeneity of demographic strategies between populations of rock ptarmigan (Lagopus muta) (2) that black grouse populations (Tetrao tetrix) show spatially very heterogeneous trends, influenced by local conditions (3) that for such species that are difficult to count and show strong spatial and interannual variability it is necessary to rely on long-term monitoring to reach a satifactory statistical power to detect a decline.
... Risulta interessante e difficilmente spiegabile la ricomparsa di tale specie a seguito di circa 20 anni dalla sua scomparsa dall'area protetta. La Pernice bianca attraversa infatti dagli anni '80 del secolo scorso una fase di declino numerico e di contrazione dell'areale in quanto oggetto di prelievo venatorio e una delle specie maggiormente minacciate dai cambiamenti climatici (Furrer et al., 2016;Peronace et al., 2012;Nardelli et al., 2015;Maffei et al., 2018). Il più vicino sito noto di presenza regolare della specie è un settore alpino a cavallo tra Italia e Svizzera, un'area compresa tra le valli Vigezzo, Isorno e Onsernone (Knaus et al., 2018). ...
... Zbinden & Salvioni (2003) Lo stato di conservazione della specie risulta sfavorevole sia a scala europea (SPEC 3) che nazionale ("Vulnerabile") (BirdLife International, 2017; Peronace et al., 2012). Le principali minacce sono rappresentate da pressione venatoria, parassiti, disturbo antropico, riscaldamento climatico, eccessivo carico di ovini e caprini ai pascoli d'alpeggio (Furrer et al., 2016;Casale et al., 2011). È una specie di interesse comunitario secondo la ...
Atlas of the Breeding Birds in Val Grande National Park, Piedmont, Italy, Western Alps. Key words: wilderness, alpine grasslands, rocky habitats, alpine heatlands, beech forests, Golden Eagle, Short-toed Eagle, Peregrine Falcon, Black Grouse, Rock Ptarmigan, Nightjar, Eagle Owl, Boreal Owl, Black Woodpecker, Alpine Accentor, Wallcreeper, Alpine Chough, Water Pipit, Tree Pipit, Rock Bunting.
... Die mittlere Höhenverteilung der Schneehuhn-Beobachtungen hat sich in der Schweiz zwar nach oben verschoben, aber nicht in allen Landesteilen gleichmäßig (Pernollet et al. 2015). Der Bestand ist insgesamt leicht rückläufig (Furrer et al. 2016, Knaus et al. 2018. Die in Abschnitt 2 aufgeführten Beispiele belegen zwar eine Höherverschiebung von einzelnen Birkhuhn-Balzplätzen in den letzten drei bis fünf Jahrzehnten, doch fanden im selben Zeitraum auch Neubildungen in den tiefer gelegenen Teilen des Lebensraums statt. ...
... Der betreffende Gratrücken schien topografisch so attraktiv zu sein, dass er trotz der Beeinträchtigung durch den Skiliftbau nach einiger Zeit wieder als Balzplatz genützt wurde. Mittlerweile sind hier aber nur noch einer bis drei balzende Hähne anzutreffen (Marti et al. 2016). ...
Long-term monitorings in a study area in (Swiss Alps) and two study areas in central Switzerland have revealed strong fluctuations but no population trend of the Black Grouse. Some leks, however, have moved considerably, mostly uphill. Climate change may be the indirect cause, but the immediate response by Black Grouse relates to changes of the vegetation structures of the habitat. The establishment of new traditional leks in areas that have become suitable for the species takes a long time. The establishment of winter sport facilities endangers Black Grouse populations causing space competition between mountain stations and leks, leading to collisions with cables and generating human disturbances. The effectiveness of habitat management measures at the upper timberline has not been proven so far. Such interventions can therefore under no circumstances be considered as compensation measures for touristic development projects. Black Grouse cannot simply be relocated to other parts of its local range restructured for this purpose.
... Alpine and Arctic species have been identified as being especially vulnerable to global warming (Beever, Ray, Wilkening, Brussard, & Mote, 2011;Hughes, 2000;Jackson, Gergel, & Martin, 2015;Moritz et al., 2008;Parmesan, 2006;Thuiller, Lavorel, & Araujo, 2005;, partly because warming may occur more rapidly at higher elevations (Pepin et al., 2015). Moreover, these species have evolved specific adaptations to cold environments and often lack the capacity to adapt quickly enough to climatic changes (Hof, Levinsky, Araujo, & Rahbek, 2011;Mace & Purvis, 2008;Parmesan, 2006) or may already be living near their physiological limits (Furrer et al., 2016;Hoffmann & Sgro, 2011). ...
... We assume that conservation activities in these patches would also enhance the population connectivity of other members of the Alpine community such as grouse species with similar habitat requirements at the upper timberline, which also occur as isolated glacial relict populations in the Alps and which are vulnerable to climate change (e.g. Braunisch et al., 2013Braunisch et al., , 2014Furrer et al., 2016;Imperio, Bionda, Viterbi, & Provenzale, 2013;Pernollet et al., 2015). Because climate change predictions are subject to high level of uncertainty ), monitoring should be integrated into an adaptive management plan for sustainably harvesting and conserving the species. ...
The majority of predictions about the impacts of climate change on wildlife have relied either on the study of species' physiological tolerance or on broad-scale distribution models. In comparison, little attention has been paid to species' mechanistic responses to fine-grained, climate-induced modifications of habitat suitability. However, such studies would be pivotal to the understanding of species' ecological requirements (and hence their adaptive potential to environmental change) and the design of management strategies. We investigated foraging microhabitat selection in a potentially climate-change sensitive species, the white-winged snowfinch Montifringilla nivalis, during the breeding season in the Alps. Our microhabitat selection model considered topography, ground-cover variables and sward height within a 5-m radius at foraging and control locations. Habitat selection was positively affected by grassland cover, negatively by sward height and quadratically by snow cover (optimum around 40%); birds avoided anthropized (urban areas, roads) sites. We estimated past (1976) and future (2066) climate-driven changes in foraging microhabitat suitability, assuming a progressively earlier date of snowmelt due to increasing temperatures over this entire time span. We then modelled the potential impact of snowmelt (and related sward height) on habitat suitability under two scenarios: maintaining the current situation (i.e. irregular seasonal grazing) and implementing targeted management in an attempt to mitigate impacts of earlier snowmelt. Predicted foraging habitat suitability (estimated as the fraction of suitable plots) significantly declined over time (−23% between 1976 and 2016, further 32% loss by 2066). However, model outputs demonstrated that maintaining sward height below 6 cm on breeding grounds (e.g. by regular grazing) would significantly decrease the predicted loss of suitable foraging habitat. Detailed information about patterns of resource exploitation allows the identification of mechanistic, functional responses of species to environmental change, and enables an evaluation of habitat management options that can buffer against the detrimental effects of global warming.bi
... Alpine and Arctic species have been identified as being especially vulnerable to global warming (Beever, Ray, Wilkening, Brussard, & Mote, 2011;Hughes, 2000;Jackson, Gergel, & Martin, 2015;Moritz et al., 2008;Parmesan, 2006;Thuiller, Lavorel, & Araujo, 2005;, partly because warming may occur more rapidly at higher elevations (Pepin et al., 2015). Moreover, these species have evolved specific adaptations to cold environments and often lack the capacity to adapt quickly enough to climatic changes (Hof, Levinsky, Araujo, & Rahbek, 2011;Mace & Purvis, 2008;Parmesan, 2006) or may already be living near their physiological limits (Furrer et al., 2016;Hoffmann & Sgro, 2011). ...
... We assume that conservation activities in these patches would also enhance the population connectivity of other members of the Alpine community such as grouse species with similar habitat requirements at the upper timberline, which also occur as isolated glacial relict populations in the Alps and which are vulnerable to climate change (e.g. Braunisch et al., 2013Braunisch et al., , 2014Furrer et al., 2016;Imperio, Bionda, Viterbi, & Provenzale, 2013;Pernollet et al., 2015). Because climate change predictions are subject to high level of uncertainty ), monitoring should be integrated into an adaptive management plan for sustainably harvesting and conserving the species. ...
Alpine and Arctic species are considered to be particularly vulnerable to climate change, which is expected to cause habitat loss, fragmentation and-ultimately-extinction of cold-adapted species. However, the impact of climate change on glacial relict populations is not well understood, and specific recommendations for adaptive conservation management are lacking. We focused on the mountain hare (Lepus timidus) as a model species and modelled species distribution in combination with patch and landscape-based connectivity metrics. They were derived from graph-theory models to quantify changes in species distribution and to estimate the current and future importance of habitat patches for overall population connectivity. Models were calibrated based on 1,046 locations of species presence distributed across three biogeographic regions in the Swiss Alps and extrapolated according to two IPCC scenarios of climate change (RCP 4.5 & 8.5), each represented by three downscaled global climate models. The models predicted an average habitat loss of 35% (22%-55%) by 2100, mainly due to an increase in temperature during the reproductive season. An increase in habitat fragmentation was reflected in a 43% decrease in patch size, a 17% increase in the number of habitat patches and a 34% increase in inter-patch distance. However, the predicted changes in habitat availability and connectivity varied considerably between biogeographic regions: Whereas the greatest habitat losses with an increase in inter-patch distance were predicted at the southern and northern edges of the species' Alpine distribution, the greatest increase in patch number and decrease in patch size is expected in the central Swiss Alps. Finally, both the number of isolated habitat patches and the number of patches crucial for maintaining the habitat network increased under the different variants of climate change. Focusing conservation action on the central Swiss Alps may help mitigate the predicted effects of climate change on population connectivity.
... Yet, the significant greening of the Alps (i.e. melting of snow and subsequent growth of plants) is causing a decline in alpine specialist species (Lin et al., 2020;Rumpf et al., 2022;Vittoz et al., 2013), while the rise in ambient temperatures has triggered the decline of boreo-alpine species (Furrer et al., 2016 ...
... Delayed snowfall in autumn had an especially negative effect, possibly due to a mismatch in time to moult to the white winter plumage, which increased the predation risk 32 . Furrer et al. 33 also proved that an upward shift of the treeline and a local increase in winter and/or summer tourism have a negative effect. We also noted sensitivity concerning climate and land use in our results; however, we did not find a negative correlation with tourism intensity. ...
Since the end of the nineteenth century, socio-economic changes have greatly altered the Central European landscape and the structural and functional quality of habitats. Urban sprawl areas have appeared, a reduction of multiple forest uses has resulted in the densification of forests and agricultural land use has changed fundamentally through specialisation and intensification. Many of these changes affect biodiversity. To determine the important drivers of spatio-temporal dynamics of the population of 28 game species, we first considered a total of 130 potential explanatory variables. Second, we aggregated the main drivers of single-species models for habitat guilds. Third, we evaluated the results to aid in the development and implementation of mitigation measures for different ecoregions. We used harvest data as a surrogate for population density from 1875 to 2014 in South Tyrol, Italy. In generalised linear models, we used environmental characteristics such as climate, landscape diversity and structures, land cover, hunting, wildlife diseases, competition and predation, land-use type, and intensity (including pesticide use) as explanatory variables to predict the spatio-temporal dynamics of game species. The important drivers are land use and management changes (intensification in the agriculturally favourable areas, extensification or abandonment in the unfavourable areas) as well as associated changes in the landscape features, diversity and structure, and hunting management. Climatic variables, interspecific competition and diseases only play a subordinate role. The dynamics of the habitat guilds and their drivers provide concrete indications for measures to maintain or improve the habitat quality for the investigated species. Particularly important are transfer payments to ensure extensive agricultural use, increasingly through the takeover of personnel costs, but also for the installation of an independent body that monitors and evaluates the effectiveness of the measures.
... This could indicate that sim ilar broad scale continental drivers are behind the changes. The reasons for these recent changes are not fully understood, and drivers of popula tion trends of a single species can differ even within a single mountain range (Furrer et al. 2016). ...
High mountain habitats are globally important for biodiversity. At least 12% of birds worldwide breed at or above the treeline, many of which are endemic species or species of conservation concern. However, due to the challenges of studying mountain birds in difficult-to-access habitats, little is known about their status and trends. This book provides the first global review of the ecology, evolution, life history and conservation of high mountain birds, including comprehensive coverage of their key habitats across global mountain regions, assessments of diversity patterns along elevation gradients, and adaptations for life in the alpine zone. The main threats to mountain bird populations are also identified, including climate change, human land use and recreational activities. Written for ecologists and naturalists, this book identifies key knowledge gaps and clearly establishes the research priorities needed to increase our understanding of the ecology of mountain birds and to aid in their conservation.
... The alpine-nival habitats improved qualitatively until the 1970/80s of the last century when considering the specialists found there; since the 1980s, especially for the populations of mountain hare and rock ptarmigan, the habitat has been deteriorating significantly, whereas the populations of the marmot have been classified in the last management plan (2022-2026) as stable. The mountain hare and the rock ptarmigan are particularly sensitive to reforestation and afforestation of open grassland areas as a consequence of abandonment of summer pastures (Furrer et al., 2016;Hulbert and Iason, 1996), in addition to climate change (Imperio et al., 2013;Rehnus et al., 2018) and disturbances by outdoor activities and pastoralism (Furrer et al., 2016a;Rehnus et al., 2014). On the other hand, marmots prefer, in contrast to the other two species, anthropogenic sites (meadows, summer pastures), where their reproduction rate was highest (Ramousse et al., 2009). ...
Urban sprawl, increased traffic and modern forestry, as well as the globalisation of agriculture, have increasingly been affecting the landscape and its quality as habitat for species especially since the middle of the last century. Still, there are hardly any methods nor indicators which can measure the quality of the landscape for species over a long period. In this study, we investigated the influence of landscape structure and landscape quality on harvest data of 28 game species in South Tyrol, Italy, over the last 150 years. The harvest data were used to assess the population dynamics of individual species and habitat guilds since 1870. As a first result, we could show, on the examples of six species, that count population data were highly correlated with harvest data and are therefore well suited to estimate their population size. Second, the populations of ungulates consistently increased during the study period. The numbers of mesocarnivores as well as smaller forest and alpine game species increased strongly until the 1970s/80s of the last century, followed by a decline. The populations of farmland species and some synanthropic species have decreased substantially, and some species have even disappeared completely. Based on these results, we were able to show, in a third step, that the landscape quality for game species in South Tyrol has developed differently: In particular, the agriculturally used habitats have lost quality, whereas forests and alpine regions have initially gained quality due to the extensification of use; during the last five decades, the quality decreases again, at least for small game species. Our results thus provide concrete implications for the active improvement of the landscape quality for farmland and forest species, as well as indications for future priorities in funding support of alpine pasture management.
... With N [i,t] the true abundance or biomass at the considered sampling event and sigma the site-specific variance (σ obs [i] 2 ). As previously stipulated by Furrer et al. (2016) and Canonne et al. (2021), this observation model assumes that log-transformed abundance or biomass values are correct on average and adjusted for site-specific residual variance to consider both site-specific observation errors and species-specific detection errors (source code of the model see Appendix S1 ...
European Union environmental policy has created a unique regulatory framework to favour aquatic ecosystem management and biodiversity conservation across European countries. Identifying the spatial structure of freshwater fish population dynamics is crucial to define region-specific management and conservation planning. To implement evidence-driven management and conservation decisions at a regional scale we assessed spatial heterogeneity in common freshwater fish population dynamics in France with a focus on trends in River Basin Districts (RBDs).
The abundance and biomass growth rates of 18 common European freshwater fish species were estimated with state-space models on 546 sites distributed across the 5 main RBDs sampled in France between 1990 and 2011. Anguilla anguilla, Rutilus rutilus, Salmo trutta fario and Esox spp. exhibited large scale decline in abundance and/or biomass in several RBDs. The other species showed spatial heterogeneity in population growth rates. The main declines were observed in the Adour-Garonne and Loire-Bretagne RBDs, where management and conservation measures are urgently needed to halt the erosion of freshwater fish populations. In each of the 5 investigated RBDs, our results highlight areas where most of the common species we studied exhibited negative population growth rates. Freshwater fish surveys provide the fundamental information necessary to inform the European environmental policies and local environmental management needed to restore freshwater biodiversity. The next steps are to identify the main drivers of freshwater biodiversity erosion in the areas where we demonstrated major declines and to define the most cost-effective restoration measures.
... Landscape modification may lead to local or regional declines (see Zabala et al., 2003;Furrer et al., 2016), and ultimately extinction (McCarthy et al., 1997). Identifying the effects of landscape changes on species is critical for the development of efficient and effective conservation strategies (Lindenmayer and Fischer, 2006). ...
Human activities transformed virtually all landscapes worldwide to fulfil their basic needs (e.g., resource extraction, agriculture or leisure activities). By doing so, they also affect species inhabiting these human-dominated landscapes. Due to their historical link to human activities, apex predators, especially vultures, are especially vulnerable to human-induced behavioural alterations and have undergone population declines worldwide. Therefore, finding a solution that reconciles vulture conservation and human activities in such landscapes is necessary. By using a set of behavioural indicators (e.g., breeding, occupancy/detectability and space use) from long-term monitoring and movement ecology, this thesis aims to build links between behaviour and conservation of Egyptian vulture Neophron percnopterus in human-dominated landscapes. The current dissertation shows that the species invests similar effort in parental care and that incubation and hatching are important tipping points during the breeding season (Chapter 1). This information could be, in turn, used to design cost-effective monitoring while accounting for imperfect detection and breeding phenology and other environmental variables that could help to adapt monitoring programs to different available budgets (Chapter 2). Similarly, the knowledge of breeding behaviour of the species could be used to infer the impact of habitat alterations on species nest occupancy and reproduction patterns and to improve conservation programs (Chapter 3), and test whether management programs and collaboration networks resulted effective in reducing the synergistic effect of various human disturbances (Chapter 4). Finally, it poses an advance in the understanding of how certain human activities that provide continuous and predictable food pulses, such as farming, could alter species space use and favour residency in partial migratory species (Chapter 5), and that human-driven changes in migratory behaviour could even have consequences on fitness and energy use of different migratory phenotypes (Chapter 6). Overall, this work demonstrates the utility of increasing vulture behaviour knowledge to ascertain the effects of human activities on the species and find coherent conservation solutions that favour its persistence and promote vulture-human coexistence in anthropogenic landscapes.
... One added value of our model is to combine count data from two protocols to estimate relative detection probability and abundance indices without physical capture of animals. Recent state-space models are usually based on a single count per time interval without accounting for detection probability, even conditional [25,52]. Our model uses counts replicated in two dimensions (multiple sites and replicate observations per site), like N-mixture models [21], but with a more flexible framework. ...
In the context of wildlife population declines, increasing computer power over the last 20 years allowed wildlife managers to apply advanced statistical techniques that has improved population size estimates. However, respecting the assumptions of the models that consider the probability of detection, such as N-mixture models, requires the implementation of a rigorous monitoring protocol with several replicate survey occasions and no double counting that are hardly adaptable to field conditions. When the logistical, economic and ecological constraints are too strong to meet model assumptions, it may be possible to combine data from independent surveys into the modelling framework in order to understand population dynamics more reliably. Here, we present a state-space model with an error process modelled on the log scale to evaluate wintering waterfowl numbers in the Camargue, southern France, while taking a conditional probability of detection into consideration. Conditional probability of detection corresponds to estimation of a detection probability index, which is not a true probability of detection, but rather conditional on the difference to a particular baseline. The large number of sites (wetlands within the Camargue delta) and years monitored (44) provide significant information to combine both terrestrial and aerial surveys (which constituted spatially and temporally replicated counts) to estimate a conditional probability of detection, while accounting for false-positive counting errors and changes in observers over the study period. The model estimates abundance indices of wintering Common Teal, Mallard and Common Coot, all species abundant in the area. We found that raw counts were underestimated compared to the predicted population size. The model-based data integration approach as described here seems like a promising solution that takes advantage of as much as possible of the data collected from several methods when the logistic constraints do not allow the implementation of a permanent monitoring and analysis protocol that takes into account the detectability of individuals.
... Dans cette étude, nous avons utilisé des modèles dits à « espace-état », similaires à ceux utilisés dans l'étude des tendances démographique du Lagopède alpin en Suisse (Furrer et al. 2016). Ces modèles nous ont permis dans un premier temps d'estimer les tendances de populations sur les sites de comptages suivis par l'OGM en prenant en compte l'erreur d'observation. ...
Le lagopède alpin est une espèce emblématique des zones de hautes altitudes, dont les populations ont subi une forte baisse ces dernières décennies. Dans un objectif de conservation de l'espèce, il est crucial de pouvoir quantifier de façon précise l'ampleur de ce déclin à différentes échelles, mais également le degré de confiance que l'on peut avoir dans les estimations de ces tendances. Pour étudier ces questions, nous nous sommes appuyés dans un premier temps sur l'analyse de tendances par modèles « espaces états » des séries de comptages de mâles de Lagopède alpin effectués sur un réseau de sites de référence répartis dans les Alpes. Les résultats nous ont permis de calibrer des simulations de tendances sur un réseau de sites, afin de mener une étude de puissance pour explorer notre capacité à détecter un déclin pour différents scénarios en comparant à la fois différents plans d'échantillonnage et plusieurs approches de modélisation. Nos résultats montrent d'une manière générale une faible puissance statistique pour détecter les tendances, en particulier pour des situations présentant de légères baisses annuelles des effectifs, mais qui peuvent cependant correspondre à des déclins prononcés sur une durée cumulée de 20 ans. La mutualisation des informations quant à la variabilité interannuelle des taux de croissance et la variance d'observation entraîne assez peu de changements dans les résultats et apparaît donc comme insuffisante pour améliorer notre capacité à détecter les déclins. Il apparait que le modèle basé sur une approche par réseau (effet aléatoire des sites) conduit à des estimations beaucoup plus précises de la tendance médiane de ce réseau, en revanche au détriment des estimations de tendances site par site, qui tendent à être biaisées et tirées en direction de la moyenne du réseau. Nos résultats ont aussi montré très peu d'influence sur la puissance statistique des paramètres du réseau. Les suivis courts (5 ou 10 ans) bénéficient légèrement de répétitions au fil des ans et d'une fréquence annuelle des visites, cependant les réplicats intra-années et des passages annuels ne semblent pas être nécessaires sur des suivis de 20 ans. Il ressort de notre étude que la puissance au sens strict est faible pour ces suivis. Il convient donc de discuter non plus seulement de significativité des tendances au seuil de 5%, mais de la force des effets (les déclins médians), ainsi que de la notion de seuil de risque pour avancer dans les mesures de gestion. Par ailleurs, notre étude suggère que pour cette espèce il faut envisager des suivis à véritablement long terme ainsi qu'à large échelle, en associant éventuellement plusieurs indicateurs pour obtenir une vision claire des dynamiques temporelles des effectifs.
... The main contribution of our long-term study is to provide updated information on dispersal and survival of young Rock Ptarmigan in the French Alps and Pyrenees. Al-though a substantial number of studies have been carried out on the demographic traits of this species throughout its distribution (Watson et al., 1998;Holder & Montgomerie, 1993;Furrer et al., 2016;Unander et al., 2016;Canonne et al., 2020), limited research has been conducted on spatial behaviour (Morscheidt et al., 1996;Favaron et al., 2006;Nilsen et al., 2020). ...
Knowledge of natal dispersal and juvenile survival from parental independence until recruitment into breeding populations is an important aspect of population dynamics studies. Dispersal allows genetic connectivity and demographic compensation between neighbouring populations. These issues are particularly significant for species confined to mountaintops, as is the Rock Ptarmigan Lagopus muta in southern Europe. We studied natal dispersal and survival in juvenile Rock Ptarmigan in the French Alps and Pyrenees between 1999 and 2018 by radiotracking 113 young captured in September in two study areas. At both sites natal dispersal occurred in two discrete phases, in autumn (October-November) and in spring (late March-mid-May). Juvenile females dispersed twice as far as males in autumn at both sites but this difference decreased in spring and was not significant. Juveniles of both sexes dispersed further in the Pyrenees than in the Alps (males: 3.5 vs. 1.4km; females: 6.5 vs. 4.4km), a situation we attribute more to genetic differences between the two populations rather than to environmental factors. As to geographical barriers to dispersal, our radiotracking data along with extensive visual observations suggest that Rock Ptarmigan living in the Alps and the Pyrenees rarely fly across valleys 10-12km wide. For sexes and locations combined, the survival rate of juvenile Rock Ptarmigan during a ten-month period (September to June) was 0.636 (95%CI: 0.551-0.734). Long-distance dispersal tended to reduce the survival of birds during their first breeding attempt (April-June), a result that suggests a delayed effect of such dispersal.—Novoa, C., Resseguier, J., Muffat-Joly, B., Blanch Casadesus, J., Arvin-Bérod, M., Gracia Moya, J. & Desmet, J.F. (2021). Natal dispersal and survival of juvenile Rock Ptarmigan Lagopus muta in the French Alps and Pyrenees. Ardeola, 68: 123-141.
... Trotz dieser Pufferfunktion kann bereits jetzt ein Rückgang des Schneehuhns in Teilen der Alpen beobachtet werden. Studien in der Schweiz zeigen allerdings, dass es starke regionale Unterschiede in der Bestandsentwicklung gibt (Pernollet et al. 2015, Furrer et al. 2016. ...
Der Klimawandel hat in vielen Fällen gravierende Auswirkungen auf die Alpenfauna. Neben phänologischen Veränderungen spielt dabei vor allem die Verschiebung der Lebensräume vieler Arten in größere Höhenlagen eine bedeutende Rolle. Alpine Arten sind besonders stark betroffen, da die Möglichkeiten, in noch größere Höhen auszuweichen, begrenzt sind. Ein Beispiel dafür ist das Alpenschneehuhn (Lagopus muta), dessen Populationen im Alpenraum im Laufe dieses Jahrhunderts stark zurückgehen werden. Ebenso betroffen sind wirbellose Arten wie die alpinen Palpenfalter der Gattung Sattleria, die vielfältige Anpassungen an die ex-tremen Bedingungen im Hochgebirge zeigen. Veränderungen sind ebenfalls in aquatischen Ökosystemen zu beobachten: Durch die Erwärmung der Fließgewässer verkleinert sich der Lebensraum einiger Fischarten, während andere von der Entwicklung profitieren. Wichtig ist in diesem Zusammenhang zudem die Umweltbil-dung, die im Kontext vom Klimawandel bestens von Zoologischen Gärten, wie dem Alpenzoo Innsbruck-Tirol übernommen wird. The wildlife of the Alps under climate change: In many cases Climate Change has serious impacts on the alpine fauna. Next to phenological changes an upward shift of habitats plays an important role. Alpine species are especially affected by climate change as the potential for migration to higher altitudes is limited. An example is the rock ptarmigan (Lagopus muta), whose populations in the alps will decrease strongly in this century. Invertebrate species such as the alpine twirler moths of the genus Sattleria, which show various adaptations to the extreme conditions in high-altitude mountains, are also affected. Changes caused by climate change can be observed in aquatic ecosystems as well: due to the heating of streaming waters some fish species lose parts of their habitat while others benefit from the development. In this context, environmental education is also important, which in the context of climate change is taken over by zoos, such as the Alpenzoo Innsbruck-Tirol.
... The subspecies L. m. pyrenaica is found across the Pyrenean range (Caizergues et al. 2003;Marty and Mossoll-Torres 2012) and lives primarily in high rocky and stony areas above the treeline (1900-2900 m a.s.l.) (Novoa and González 1987). The monitoring of this subspecies is challenging due to the rugged terrain and harsh climate of its habitats (López-Moreno and Vicente-Serrano 2007;Aubry 2011;Marty and Mossoll-Torres 2012;Pedersen et al. 2012) and due to its cryptic nature and elusive behaviour (Favaron et al. 2006;Pedersen et al. 2012;Jakob and Ponce-Boutin 2013;Furrer et al. 2016). ...
The rock ptarmigan (Lagopus muta) has a wide Holarctic geographical range, within which its status changes locally from threatened to abundant. For the correct management of populations under differing scenarios, accurate and precise estimates of bird abundances and/or densities are required. We used geolocated datasets from 56 counts of singing males carried out in 2003–2017 to estimate the density of Pyrenean rock ptarmigans (Lagopus muta pyrenaica). We analysed these datasets using two methodologies: (1) a plot sampling (PS) approach with two effective detection ranges (EDR) of 250 m and 350 m and (2) a conventional distance sampling (DS) approach. Our results showed that the density estimates obtained by DS were more precise and 30–87% higher than those obtained by PS using 250 m and 350 m EDR. Monitoring with PS underestimates populations and is less precise than DS; this bias is magnified when high EDR values are used. The monitoring of the Pyrenean rock ptarmigan could be significantly improved with greater use of the DS method.
... We found that summer survival is lower than winter survival for both sexes in adult alpine choughs. Cold-adapted vertebrates are known to be directly or indirectly impacted by warm summer temperatures (Furrer et al. 2016), influencing their foraging strategy (Mason et al. 2017), body condition (Gardner et al. 2016) and survival probability (White et al. 2011). ...
Du fait de la croissance démographique et économique de la population humaine, nos sociétés sont de plus en plus dépendantes de la nature, et plus précisément de certains processus biologiques regroupés sous le terme services écosystémiques. Comprendre les mécanismes de réponse des systèmes biologiques face aux changements globaux que nos activités induisent à plusieurs échelles est donc un enjeu scientifique et de société. Cette thèse a été pensée et réalisée en interaction avec plusieurs équipes de recherche et gestionnaires d’espaces naturels dans le cadre du développement d’un suivi temporel des oiseaux de montagne comme indicateurs des conséquences des changements globaux sur la biodiversité. Les massifs montagneux de France sont en effet exposés aux changements de climat et à l’évolution de l’élevage des grands herbivores, une activité exposée aux fluctuations des prix des matières premières et des aides publiques. Les forts gradients bioclimatiques « en facettes » (selon l’exposition) qui caractérisent des massifs montagneux font de ces espaces des modèles d’étude particulièrement intéressants pour étudier les effets des changements globaux sur la biodiversité, mais aussi fortement contingents. L’objet général de ma thèse est d’identifier et de quantifier le rôle respectif de la température, de la structure de la végétation, et des activités d’élevage, sur cette communauté d’oiseaux, afin de mieux comprendre quelles pourraient être les conséquences de changements majeurs de climat et d’usage des terres. Les gradients altitudinaux ont été historiquement étudiés de façon isolée et dans de grandes diversités d’habitats. Suivant les objectifs généraux de la thèse nous avons choisi d’adopter l’approche inverse dans le premier chapitre, en multipliant les sites d’études dans un habitat standardisé (1100 points d’écoute réalisés dans les Alpes et les Pyrénées). Nos résultats montrent que la ressource, la température et la structure de l’habitat influent fortement sur la communauté. De plus 5 des 8 espèces étudiées semblent favorisées par le pâturage. Dans le second chapitre, j’ai testé l’effet de la forte saisonnalité qui caractérise le climat des massifs montagneux tempérés, en testant son effet sur la survie individuelle dans une population de Chocards à bec jaune Pyrrhocorax graculus. Je me suis appuyé pour cela sur un suivi individuel (CMR) d’un millier d’individus mené pendant 30 ans par Anne Delestrade. Les Chocards présentent une survie forte et un patron saisonnier, en interaction avec le sexe des individus, avec une survie plus basse pour les femelles après les hivers et printemps chauds. J’ai ensuite présumé que les passereaux insectivores savent profiter des troupeaux en consommant des insectes coprophages. J’ai mesuré les ratios isotopiques stables de l’azote présents dans les fèces des oiseaux les plus communs pour estimer le niveau trophique de leurs proies, et ainsi tester cette hypothèse et quantifier le mécanisme. On observe dans les deux massifs un décalage très marqué vers le prélèvement d’insectes non-herbivores quand l’intensité de pâturage augmente. Le dernier chapitre évalue le potentiel d’échantillonnages itératifs basés sur des modèles de répartition d’espèces pour augmenter la probabilité de contacter une espèce rare dans de nouvelles localités. Cette étude comprend des simulations et un test de terrain dans les Pyrénées sur la Niverolle alpine Montifringilla nivalis et le Monticole de roche Monticolla saxatilis. Les résultats montrent le fort potentiel de la méthode en pratique, et ses limites, avec une augmentation de la spécificité au détriment d’une augmentation des omissions. En discussion générale, je propose des perspectives de recherche visant à généraliser le lien fort entre régime alimentaire des oiseaux de montagne et troupeaux de mammifères herbivores, et à mieux comprendre la phénologie des populations des pelouses d’altitude en fonction de l’enneigement.
... Another approach to evaluating synchrony is to use models with random effects that partition temporal variation among populations or species into synchronous and asynchronous components. Examples using this method include assessment of nonindependence in survival rates among seabird populations and species (Grosbois et al., 2009;Lahoz-Monfort et al., 2011), as well as estimation of trends and synchrony in observations of alpine rock ptarmigans (Furrer et al., 2016). Numerous other approaches have examined spatial synchrony without explicitly considering long-term trends, with cross-correlation coefficients perhaps the most commonly-used index of synchrony (Buonaccorsi et al., 2001;Jones et al., 2003;Ranta et al., 1995). ...
... In contrast to the northern population, characterized by high density and occurring in wide and undisturbed habitats (Caizergues et al., 2003), the southernmost populations, which present a more fragmented distribution, have suffered a significant population reduction over the last decade. The decline may be explained by the climate change and human disturbance (Storch, 2000;Revermann et al., 2012;Imperio et al., 2013;Desmet, 2014;Novoa et al., 2014;Furrer et al., 2016), that are reducing even more the areas suitable for the presence of the species. ...
Data presented in this work represents the first record of parasites from the Alpine and Pyrenean Lagopus muta subspecies, providing valuable information to consider for conservation management. From 1987 to 2018, 207 Rock ptarmigans were collected in the framework of a long-term sanitary monitoring in France. Eight parasites were found in the Alpine Rock ptarmigan, and one in the Pyrenean subspecies. Only two parasites occurred with high prevalence in the Alpine Rock ptarmigan: Capillaria caudinflata (38.9%) and Eimeria sp. (34.7%). Prevalence of the other parasites (Ascaridia compar, Cestodes, Amphimerus sp. and Trichostrongylus tenuis) was lower than 20%. Dispharynx nasuta was found with a prevalence of 52.9% in the Pyrenean Rock ptarmigan. Overall, we found a spatially aggregated distribution of parasites in the northern French Alps, probably due to both favourable climatic conditions for parasite cycle and high host density. Statistical analyses indicated a positive effect of altitude and latitude on C. caudinflata occurrence whereas risk factors for Eimeria sp. were the distance from urban areas and land cover. In addition, the majority of the infested birds came from areas close to ski-pistes, where human disturbance increases the susceptibility to diseases, causing stress to wildlife.
... De nombreuses observations ont montré que les populations tendaient à diminuer dans les parties marginales de leur aire de distribution (source Observatoire des Galliformes de Montagne (OGM)). De plus, il a été montré que l'impact combiné de l'activité humaine et du changement climatique pouvait même se traduire par des extinctions locales (Imperio, 2013 ;Furrer, 2016 ;Martinoli et al, 2017). ...
Population censuses of male rock ptarmigans (Lagopus muta) are conducted by point count protocol in
spring (late May - early June). Several observers are placed at given points within the area and spend an
hour listening to singing males trying to deduce an estimate of their number. The counting conditions are
diffcult and cast doubt on the good representativeness of this protocol. The first objective of this thesis was
to quantify the counting biases. The thesis then focused on finding ways to develop new counting methods to
compensate for the biases of traditional counting. The acoustic signals emitted by animals carry several levels
of information, such as the identity of the transmitter. The second part of my thesis showed that bioacoustic
techniques based on acoustic differences in vocalizations were suitable to ptarmigan and that it was possible
to determine the number of males in an area using the sounds they produce. The third part of the thesis is a
generalization of the method on long-term recordings under real field conditions. It was not only possible to
obtain the number of males but also the time of presence of each male and to assess his reproductive status.
In conclusion, I showed the interest of the bioacoustic tool to monitor ptarmigan’s populations. My thesis
opens up perspectives for futur large scale monitoring of ptarmigan’s populations.
... We found that summer survival is lower than winter survival for both sexes in adult alpine choughs. Cold-adapted vertebrates are known to be directly or indirectly impacted by warm summer temperatures (Furrer et al., 2016), influencing their foraging strategy (Mason, Brivio, Stephens, Apollonio, & Grignolio, 2017), body condition (Gardner et al., 2016), and survival probability (White et al., 2011). However, we found no evidence of a correlation between summer survival, mean summer temperature, and mean summer precipitation in the alpine chough. ...
Abstract Climate seasonality is a predominant constraint on the lifecycles of species in alpine and polar biomes. Assessing the response of these species to climate change thus requires taking into account seasonal constraints on populations. However, interactions between seasonality, weather fluctuations, and population parameters remain poorly explored as they require long‐term studies with high sampling frequency. This study investigated the influence of environmental covariates on the demography of a corvid species, the alpine chough Pyrrhocorax graculus, in the highly seasonal environment of the Mont Blanc region. In two steps, we estimated: (1) the seasonal survival of categories of individuals based on their age, sex, etc., (2) the effect of environmental covariates on seasonal survival. We hypothesized that the cold season—and more specifically, the end of the cold season (spring)—would be a critical period for individuals, and we expected that weather and individual covariates would influence survival variation during critical periods. We found that while spring was a critical season for adult female survival, it was not for males. This is likely because females are dominated by males at feeding sites during snowy seasons (winter and spring), and additionally must invest energy in egg production. When conditions were not favorable, which seemed to happen when the cold season was warmer than usual, females probably reached their physiological limits. Surprisingly, adult survival was higher at the beginning of the cold season than in summer, which may result from adaptation to harsh weather in alpine and polar vertebrates. This hypothesis could be confirmed by testing it with larger sets of populations. This first seasonal analysis of individual survival over the full life cycle in a sedentary alpine bird shows that including seasonality in demographic investigations is crucial to better understand the potential impacts of climate change on cold ecosystems.
... It is highly adapted to its environment, has mimetic plumage and vocalizes at dawn and dusk (MacDonald, 1970). Population abundances are decreasing in both the Alps (Imperio et al., 2013;Furrer et al., 2016;Martinoli et al., 2017) and the Pyrenees, where they are threatened by both climate change and habitat transformation (Revermann et al., 2012;Bech et al., 2013). Due to these extreme environmental and selective pressures, rock ptarmigan is often considered as a bioindicator of the ecosystem health, a sentinel and umbrella species for biodiversity conservation of the alpine environments (Sandercock et al., 2005;Hanser and Knick, 2011;Henden et al., 2017). ...
... Species differ greatly in both their behavioral and reproductive responses to human disturbance and landscape changes, as well as to the relationships between these two variables (Beale & Monaghan, 2004;Finney, Pearce-Higgins & Yalden, 2005;Gu enette & Villard, 2005;Carrete et al., 2013). Landscape modification may lead to local or regional declines (see Zabala et al., 2003;Furrer et al., 2016), and ultimately extinction (McCarthy, Lindenmayer & Dreschler, 1997). Identifying the effects of landscape changes on species is critical for the development of efficient and effective conservation strategies (Lindenmayer & Fischer, 2006). ...
Anthropogenic activities are one of the main threats to species living in human‐dominated landscapes and can promote behavioral changes in birds. This paper presents a novel approach to test how a migratory species responds to habitat alterations occurring in nesting territories during winter, when the species is absent. From 2000 to 2016, we collated territory and nest monitoring data for the endangered Egyptian Vulture Neophron percnopterus in the north of Spain, to test the effects of overwinter habitat alterations (OHA) around breeding territories on the species reproductive output. We monitored 70 different nest sites and observed OHA around the nesting area in 39 cases. Probability of switching to another nesting site almost tripled after OHA. Pairs that switched experienced substantially decreased breeding success and avoided reusing the nest for 4.8 ± 4.64 years. The presence of determinate landscape elements that provide screening, such as forest patches, increased nest reoccupancy probability after OHA by more than 0.3, to 0. 55 (compared to 0.24 when no screening was present). We also found that the distance and the situation of the OHA were critical factors explaining reproduction probabilities at nest sites. Our results demonstrate how OHA can strongly impact the breeding behavior of long‐lived species. This highlights the need to examine the long‐term impact of OHA rather than focusing only on disturbances during sensitive periods, as is often the case with habitual mitigation measures.
... Some find positive changes in lower-elevation species and negative changes in higher-elevation species that are consistent with elevation shifts, as lower-elevation species colonize mountains and higher-elevation species lose suitable habitat (Flousek et al. 2015). However, others have reported opposite (Archaux 2007) or inconsistent patterns (Zamora & Barea-Azc on 2015, Furrer et al. 2016. Tingley and Beissinger (2013) found a decrease in total species richness and in species richness of high-elevation species over time in the Sierra Nevada, despite heterogeneous shifts in individual species in the same area (Tingley et al. 2012). ...
... Besides the upshift of the treeline, various factors may act locally to different degrees, such as local increase in winter and/or summer tourism and unsustainable hunting (Furrer et al., 2016). Anthropogenic pressures in mountain areas (Chamberlain et al., 2016b), such as increasing disturbance caused by high altitude ski-pistes (Caprio et al., 2011), may in the future have serious consequences for the rock ptarmigan and, more in general, for bird species dwelling above the treeline, although evidence for the effects of these factors, either positive or negative, on mountain bird populations is absent so far (Chamberlain et al., 2016a(Chamberlain et al., , 2016b. ...
High mountain systems are predicted to be especially vulnerable to the impact of climate change, with the climatically-constrained tree limit rapidly shifted upslope. In turn, the impact of upward treeline migration on mountain-dwelling bird species is expected to significantly reduce habitat suitability.
We developed the first projection of the expected climate-driven rise of the whole treeline (19,256 km) of the Italian Alps. The study area extends over 20,700 km2, ranging over 550 km in longitude and 320 km in latitude. We then investigated how much the expected treeline rise will induce a) shrinking and shifting of the elevation range and b) loss in suitable habitat for the flagship species rock ptarmigan, an alpine bird species dwelling above the treeline and, similarly to many other alpine species, highly vulnerable to treeline rise. We also investigated the potential gain in suitable habitat for rock ptarmigan due to the climate-driven upshift in the uppermost thermal limit.
At lower altitudes (1500–1600 m a.s.l.), the average expected upshift in the current treeline resulted in 195, 274 and 354 m over the short (2010–2039), medium (2040–2069) and long term (2070–2099) respectively. Above 2400 m a.s.l., it was less than 30 m even in the long term. Overall, during the three climate periods the extent of suitable habitat for rock ptarmigan above the current treeline is projected to decrease by 28.12%, 38.43% and 49.11% respectively. In contrast, the expected gain in suitable habitat due to the shift in the uppermost thermal limit will be severely restrained by the limited surface extension in the top portion of the Italian Alps.
The presented approach can promote similar studies elsewhere in the globe, providing a regional perspective to the projection of climate change impact on bird species dwelling above the treeline
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http://www.sciencedirect.com/science/article/pii/S0048969717305338
... Altitude was the main factor affecting the use of space by Rock Ptarmigan in both study areas, as shown both by the logistic regression and Ivlev Electivity Index. The effect of altitude, linked with temperature, is consistent with recent studies on the species that show that the temperature in July is a major factor shaping distribution, at both the macro and micro scales (Revermann et al. 2012;Visinoni et al. 2015;Furrer et al. 2016). In area CACN4, where Fig. 3. Frequency of elevation, slope, aspect and habitat category at CACN4 study site (left) and frequency of the same topographic variables for the Rock Ptarmigan locations (right). ...
We analysed space use strategies in two populations of Alpine Rock Ptar-migan Lagopus muta helvetica considering three topographical variables (elevation, slope and aspect) to investigate whether populations living at range margins can adapt to suboptimal conditions by exploiting the available habitat differently. Selection for topographic features differed between populations, suggesting that Rock Ptarmigan adapt their habitat selection to local availability. Therefore, we suggest considering a wide range of habitat parameters when planning conservation strategies for species living at the margins of their range.
... Die Ergebnisse von 40 Zählflächen im Schweizer Alpenraum (Isler & Bossert 2015) zeigen insgesamt eine Abnahme von 13 % in 18 Jahren (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012). Der Bestand entwickelte sich auf den einzelnen Flächen unterschiedlich (-50 % bis +6 %); das Fehlen synchroner Zuund Abnahmen zeigt, dass die Schwankungen nicht mit einem Einflussfaktor allein erklärt werden können (Furrer et al. 2016). ...
In the Aletsch region (canton of Valais, Switzerland), Black Grouse cocks are counted on their leks in spring, and Rock Ptarmigan in their territories, normally during at least two morning activity periods. The spring number of Black Grouse cocks in a study area of 5 km2 has fluctuated since 1970 without showing a trend, with a minimum of 13 cocks in the years 1998 and 2000 and a maximum of 38 cocks in 1990 and 1993. The number of Rock Ptarmigan in an adjacent part has increased from 17 cocks at the beginning of our censuses in 1974 to a maximum of 33 cocks in 1983 and 1984; then it decreased to a single cock in 2006. Since then, the population has increased again to 7–10 cocks. The area occupied by Ptarmigan decreased from about 4 to 2 km2. The decrease of Rock Ptarmigan numbers may have partly been influenced by climate warming. In a large part of the study area the abandonment of territories was caused by the growth of Arolla pines Pinus cembra and other trees. The Black Grouse leks moved during the study. The most important lek moved uphill by 120 m reaching a mountain ridge at 2210 m a.s.l. above the tree line. As in Ptarmigan, the changes are caused by the vegetation growing higher and denser. Our results show the importance of long-term monitoring programmes.
... In the same period, black grouse numbers declined by up to 20% in Italy (Peronace et al. 2012). Whether these declining trends that also persist on a global scale (Storch 2007) are already caused by the effects of climate change, or potentially other anthropogenic influences, is unknown and analyses are aggravated by the fact that population declines vary in size among regions (Furrer et al. 2016). However, with ongoing climate change effects, both rock ptarmigan and black grouse will have to track the shift of the tree line to higher elevations, a trend that is already visible in rock ptarmigan (Pernollet et al. 2015). ...
Rock ptarmigan (Lagopus muta) and black grouse (Tetrao tetrix) are two closely related alpine bird species that form relict populations in the European Alps. Besides manifold anthropogenic influences in this region, global climate change is forecast to lead to significant changes in temperatures and precipitation. We here analysed stable isotope ratios (δ13C and δ15N) of feathers of both bird species and their potential dietary plants across a longitudinal precipitation gradient in south-east Switzerland.
... The alpine-nival habitats improved qualitatively until the 1970/80s of the last century when considering the specialists found there; since the 1980s, especially for the populations of mountain hare and rock ptarmigan, the habitat has been deteriorating significantly, whereas the populations of the marmot have been classified in the last management plan (2022-2026) as stable. The mountain hare and the rock ptarmigan are particularly sensitive to reforestation and afforestation of open grassland areas as a consequence of abandonment of summer pastures (Furrer et al., 2016;Hulbert and Iason, 1996), in addition to climate change (Imperio et al., 2013;Rehnus et al., 2018) and disturbances by outdoor activities and pastoralism (Furrer et al., 2016a;Rehnus et al., 2014). On the other hand, marmots prefer, in contrast to the other two species, anthropogenic sites (meadows, summer pastures), where their reproduction rate was highest (Ramousse et al., 2009). ...
The project Climate Change in South Tyrol aims to study the effects of
climate change (CC) on the water balance and the consequences for the
vegetation in a dry Alpine region, using an innovative multidisciplinary
approach that combines modelling and experimentation. Regional climate
scenarios predict a temperature increase and a summer precipitation
decrease for the European Alps. This will likely lead to drier
conditions, especially during the vegetation growth period. As this
evolution will be more problematic in already dry regions, the inner
Alpine continental Mazia Valley (South Tyrol, Italy) was chosen as study
area in 2009 for long-term ecological research. As a preliminary case
study, the extreme 2002-2003 water year was selected to simulate a
retrospective water balance at catchment scale, using the hydrological
model GEOtop. The model proved to simulate realistic values for the
spatial and temporal dynamics of soil moisture, evapotranspiration, snow
cover and runoff production, depending on soil properties, land cover,
land use intensity and catchment morphology. In the study area of Mazia
Valley 13 monitoring stations were installed in fall 2009 to
continuously measure soil moisture, biomass production, as well as
standard micrometeorological variables. The stations were distributed
over the whole catchment to encompass its variability in elevation,
slope aspect, soil properties, and land cover. Furthermore, snow depth
and snow water equivalent were recorded at representative points
throughout the catchment. In addition, the spatial distribution of the
snow cover was determined by means of remote sensing and the discharge
of the catchment was measured as integrating hydrological variable. The
use of different types of data permits a multi-scale validation of the
model, in order to close the water balance and accurately estimate the
space-time evolution of soil moisture, evapotranspiration and snow cover
both at the plot and at the catchment scale. A first analysis of the
comparison of model simulations and measured data is presented for the
2009 - 2010 winter season. The results of this study will help to
evaluate the problem of increasing water scarcity in mountain ecosystems
due to CC and to build thus a valuable base for appropriate adaptation
strategies.
1. Understanding the population dynamics of aquatic species and how inter-specific variation in demographic and life history traits influence population dynamics is crucial to define their conservation status and design appropriate protection measures.
2. The abundance and biomass growth rates for 18 common European freshwater fish species were estimated using data spanning 1990-2011 for 546 sites across France. Fish-length trends were assessed using quantile regressions and correlations with life history traits were investigated.
3. Amongst the 18 species, eleven of them have exhibited a significant decline in abundance and 14 species declined in biomass, seven remained stable or exhibited positive abundance growth rates; for four species, biomass was stable or increased. Of the demographic and ecological traits investigated, life-history strategy and maximum length were significantly correlated with species' population growth rates, revealing that the decline mainly concerned large-bodied species with slow life-histories.
4. These results focus on 18 common European species representing 94% of fish captured during the study period within the French national monitoring programme and underline that more attention should be paid to the decline in common species. Population dynamics of widely distributed common species are key drivers of communities and of importance to ecosystem function.
5. This study provides evidence of declines in common European freshwater fish species at a national scale and recommends conservation measures to favour recovery of most declining species. We highlight the crucial value of electrofishing monitoring programmes to assess freshwater fish species population trajectories and to support environmental management and conservation policy based on scientific evidences.
Information on the abundance of the Italian populations of black grouse (Lyrurus tetrix), Alpine rock ptarmigan (Lagopus muta helvetica) and Alpine rock partridge (Alectoris graeca saxatilis) rely only on extrapolations of local data to the national scale, since there is no national standardized survey. Consequently, their status is virtually unknown. We performed a first-ever assessment of a medium-term (1996–2014) population trend of these species using and comparing post-breeding count and bag data at hunting district scale. These data were collected from various authorities in charge of wildlife management and allowed us to test the influence of hunting policies on the estimated trends. Rock partridge showed a stable trend with numbers fluctuating between years, while there was evidence of a severe decline for rock ptarmigan. No general conclusion could be drawn for the black grouse, as we detected lack of consistency of count and bag data. Counts were greatly overdispersed as a result of an uneven count effort among hunting districts. Adding the game management authority as model covariate resulted in more robust trend estimations, suggesting a significant effect of different policies that emerged also as similar hunting pressure across species within authorities. Hunting effort variation over the time was instead negligible. Species-specific game management bias is discussed. Our results highlight the need for a survey scheme or guidelines to be applied uniformly at a national scale.
Numerous mountain bird species are being forced out of lower mountain regions and can only survive at higher altitudes. The reasons for this displacement are global warming and the intensive use of the birds’ habitats. It is uncertain how quickly and for how long the species will be able to respond to these changes. The pdf of the report as well as additional content can be obtained online in four languages:
English: www.vogelwarte.ch/state
German: www.vogelwarte.ch/zustand
French: www.vogelwarte.ch/etat
Italian: www.vogelwarte.ch/situazione
Fractional snow-covered area (SCA) is a key parameter in large-scale hydrological, meteorological
and climate models. Since SCA affects albedos and surface energy balance fluxes, it is especially
of interest over mountainous terrain where generally a reduced SCA is observed in large grid
cells. Temporal and spatial snow distributions are however difficult to measure over complex
topography. We therefore present a parameterization of the SCA based on a new subgrid
parameterization for the standard deviation of snow depth over complex topography. Highly-resolved
snow depth data at peak of winter were used from two distinct climatic regions, in eastern
Switzerland and in the Spanish Pyrenees. Topographic scaling parameters are derived assuming
Gaussian slope characteristics. We use computationally cheap terrain parameters, namely the
correlation length of subgrid topographic features and the mean squared slope. A scale dependent
analysis was performed by randomly aggregating the alpine catchments in domain sizes ranging from
50 m to 3 km. For the larger domain sizes, snow depth was predominantly normally
distributed. Trends between terrain parameters and standard deviation of snow depth were similar
for both climatic regions, allowing to parameterize the standard deviation of snow depth based on
terrain parameters. To make the parameterization widely applicable, we introduced the mean snow
depth as a climate indicator. Assuming a normal snow distribution and spatially homogeneous melt,
snow cover depletion curves were derived for a broad range of coefficients of variations. The most
accurate closed form fit resembled an existing SCA parameterization. By including the subgrid
parameterization for the standard deviation of snow depth, we extended the SCA parameterization
for topographic influences. For all domain sizes we obtained errors lower than 10% between
measured and parameterized SCA.
The Alpine Rock Ptarmigan (Lagopus muta helvetica)—which is adapted to arctic and alpine environments—is suspected to be vulnerable to climate warming, but direct evidence is limited. Microclimates within a landscape may allow species to exist in regions where the general climate appears to be unsuitable for them. We therefore investigated the diversity of microclimates in alpine habitats used by the Alpine Rock Ptarmigan in summer, and we examined whether Alpine Rock Ptarmigan select places with a microclimate that facilitates heat dissipation during summer days. The study was done in the Haute-Savoie (northern French Alps), where ptarmigan have been equipped with radio transmitters, thus allowing direct observations. We measured the three microclimate variables which determine the thermal environment of an animal: ambient temperature (ground and air temperature), which defines the temperature gradients between the animal and the environment; wind speed, which determines convection; and solar radiation, which determines radiation uptake. Additional measurements at four contrasting microtopographic sites at five locations and at two random sites in July and August showed that the typical habitat of the Alpine Rock Ptarmigan offered a wide variety of microclimates over very short distances, particularly on hot summer days. Compared with control sites at 5 m and 30 m, Alpine Rock Ptarmigan selected places with a particular microtopography and microclimate: slightly cooler places in the shade that were protected from the wind; often small, north-facing depressions with a medium amount of rocks and diverse ground cover. The places selected by ptarmigan during hot summer days conformed well to the requirements of both heat dissipation and predator avoidance, and also offered food.
Long-term datasets for high-elevation species are rare, and considerable uncertainty exists in understanding how high-elevation populations have responded to recent climate warming. We present estimates of demographic vital rates from a 43-year population study of white-tailed ptarmigan (Lagopus leucura), a species endemic to alpine habitats in western North America. We used capture-recapture models to estimate annual rates of apparent survival, population growth, and recruitment for breeding-age ptarmigan, and we fit winter weather covariates to models in an attempt to explain annual variation. There were no trends in survival over the study period but there was strong support for age and sex effects. The average rate of annual growth suggests a relatively stable breeding-age population ( = 1.036), but there was considerable variation between years for both population growth and recruitment rates. Winter weather covariates only explained a small amount of variation in female survival and were not an important predictor of male survival. Cumulative winter precipitation was found to have a quadratic effect on female survival, with survival being highest during years of average precipitation. Cumulative winter precipitation was positively correlated with population growth and recruitment rates, although this covariate only explained a small amount of annual variation in these rates and there was considerable uncertainty among the models tested. Our results provide evidence for an alpine-endemic population that has not experienced extirpation or drastic declines. However, more information is needed to understand risks and vulnerabilities of warming effects on juveniles as our analysis was confined to determination of vital rates for breeding-age birds.
Fractional snow-covered area (SCA) is a key parameter in large-scale hydrological,
meteorological and climate models. Since SCA affects albedos and surface energy
balance fluxes, it is especially of interest over mountainous terrain where generally a
reduced SCA is observed in large grid cells. Temporal and spatial snow distributions
are however difficult to measure over complex topography. We therefore present a parameterization
of the SCA based on a new subgrid parameterization for the standard
deviation of snow depth over complex topography. Highly-resolved snow depth data at
peak of winter were used from two distinct climatic regions, in eastern Switzerland and in the Spanish Pyrenees. Topographic scaling parameters are derived assuming Gaussian
slope characteristics. We use computationally cheap terrain parameters, namely
the correlation length of subgrid topographic features and the mean squared slope. A
scale dependent analysis was performed by randomly aggregating the alpine catchments
in domain sizes ranging from 50 m to 3 km. For the larger domain sizes, snow depth was predominantly normally distributed. Trends between terrain parameters and
standard deviation of snow depth were similar for both climatic regions, allowing to parameterize
the standard deviation of snow depth based on terrain parameters. To make
the parameterization widely applicable, we introduced the mean snow depth as a climate
indicator. Assuming a normal snow distribution and spatially homogeneous melt, snow cover depletion curves were derived for a broad range of coefficients of variations.
The most accurate closed form fit resembled an existing SCA parameterization.
By including the subgrid parameterization for the standard deviation of snow depth, we
extended the SCA parameterization for topographic influences. For all domain sizes
we obtained errors lower than 10% between measured and parameterized SCA.
Six snow depth and total precipitation time series recorded in Western Italian Alps between 960 and 2,177 m a.s.l. have been analyzed to investigate variability and trends over the period 1926–2010. The results outline a significant decrease of snow depth in the period 1951–2010 ranging from −0.2 cm/year in the lowest station up to −1.4 cm/year in the highest one. The contribution to this negative trend comes mainly from spring. These results have been related to the changes in the amount/frequency of total precipitation and to the temperatures analyzed in former studies. The connections between winter precipitation and large-scale atmospheric forcings have been investigated by looking for regular oscillations embedded in the time series. Two different techniques have been used, the MultiTaperMethod and the Monte Carlo Singular Spectral Analysis. Both highlight oscillations corresponding to 2.4–2.7 year periods which are found to be driven by the North Atlantic Oscillation.
Gridded snow water equivalent (SWE) data sets are valuable for estimating the
snow water resources and verify different model systems, e.g. hydrological,
land surface or atmospheric models. However, changing data availability
represents a considerable challenge when trying to derive consistent time
series for SWE products. In an attempt to improve the product consistency, we
first evaluated the differences between two climatologies of SWE grids that
were calculated on the basis of data from 110 and 203 stations, respectively.
The "shorter" climatology (2001–2009) was produced using 203 stations
(map203) and the "longer" one (1971–2009) 110 stations
(map110). Relative to map203, map110
underestimated SWE, especially at higher elevations and at the end of the
winter season. We tested the potential of quantile mapping to compensate for
mapping errors in map110 relative to map203. During a
9 yr calibration period from 2001 to 2009, for which both map203
and map110 were available, the method could successfully refine the
spatial and temporal SWE representation in map110 by making
seasonal, regional and altitude-related distinctions. Expanding the
calibration to the full 39 yr showed that the general underestimation of
map110 with respect to map203 could be removed for the
whole winter. The calibrated SWE maps fitted the reference (map203)
well when averaged over regions and time periods, where the mean error is
approximately zero. However, deviations between the calibrated maps and
map203 were observed at single grid cells and years. When we looked
at three different regions in more detail, we found that the calibration had
the largest effect in the region with the highest proportion of catchment
areas above 2000 m a.s.l. and that the general underestimation of
map110 compared to map203 could be removed for the entire
snow season. The added value of the calibrated SWE climatology is illustrated
with practical examples: the verification of a hydrological model, the
estimation of snow resource anomalies and the predictability of runoff
through SWE.
Seasonal snow cover is of great environmental and socio-economic importance for the European Alps. Therefore a high priority has been assigned to quantifying its temporal and spatial variability. Complementary to land-based monitoring networks, optical satellite observations can be used to derive spatially comprehensive information on snow cover extent. For understanding long-term changes in alpine snow cover extent, the data acquired by the Advanced Very High Resolution Radiometer (AVHRR) sensors mounted onboard the National Oceanic and Atmospheric Association (NOAA) and Meteorological Operational satellite (MetOp) platforms offer a unique source of information.
In this paper, we present the first space-borne 1 km snow extent climatology for the Alpine region derived from AVHRR data over the period 1985–2011. The objective of this study is twofold: first, to generate a new set of cloud-free satellite snow products using a specific cloud gap-filling technique and second, to examine the spatiotemporal distribution of snow cover in the European Alps over the last 27 yr from the satellite perspective. For this purpose, snow parameters such as snow onset day, snow cover duration (SCD), melt-out date and the snow cover area percentage (SCA) were employed to analyze spatiotemporal variability of snow cover over the course of three decades. On the regional scale, significant trends were found toward a shorter SCD at lower elevations in the south-east and south-west. However, our results do not show any significant trends in the monthly mean SCA over the last 27 yr. This is in agreement with other research findings and may indicate a deceleration of the decreasing snow trend in the Alpine region. Furthermore, such data may provide spatially and temporally homogeneous snow information for comprehensive use in related research fields (i.e., hydrologic and economic applications) or can serve as a reference for climate models.
Alpine grouses are particularly vulnerable to climate change due to their adaptation to extreme conditions and to their relict distributions in the Alps where global warming has been particularly marked in the last half century. Grouses are also currently threatened by habitat modification and human disturbance, and an assessment of the impact of multiple stressors is needed to predict the fate of Alpine populations of these birds in the next decades. We estimated the effect of climate change and human disturbance on a rock ptarmigan population living in the western Italian Alps by combining an empirical population modelling approach and stochastic simulations of the population dynamics under the a1B climate scenario and two different disturbance scenarios, represented by the development of a ski resort, through 2050.The early appearance of snow-free ground in the previous spring had a favorable effect on the rock ptarmigan population, probably through a higher reproductive success. On the contrary, delayed snowfall in autumn had a negative effect possibly due to a mismatch in time to molt to white winter plumage which increases predation risk. The regional climate model PROTHEUS does not foresee any significant change in snowmelt date in the study area, while the start date of continuous snow cover is expected to be significantly delayed. The net effect in the stochastic projections is a more or less pronounced (depending on the model used) decline in the studied population. The addition of extra-mortality due to collision with ski-lift wires led the population to fatal consequences in most projections. Should these results be confirmed by larger studies the conservation of Alpine populations would deserve more attention. To counterbalance the effects of climate change, the reduction of all causes of death should be pursued, through a strict preservation of the habitats in the present area of occurrence.
Ongoing monitoring in the Swiss Alps has shown that Rock Ptarmigan (Lagopus muta helvetica) has suffered a significant population decrease over the last decade and climate change has been proposed as a potential cause. In this study, we investigate the response of this high alpine grouse species to rapid climate change. We address a problem often neglected in macro-ecological studies on species distribution: scale-dependency of distribution models. The models are based on empirical field data and on environmental databases for large-scale models. The implementation of several statistical modelling approaches, external validation strategies and the implementation of a recent study on regional climate change in Switzerland ensure robust predictions of future range shifts. Our results demonstrate that, on the territory level, variables depicting vegetation, heterogeneity of local topography and habitat structure have greatest explanatory power. In contrast at the meso-scale and macro-scale (with grain sizes of 1 and 100 km 2 , respectively), bioclimatic and land cover-related variables play a prominent role. The models predict that, based on increasing temperatures during the breeding season, potential habitat will decrease by up to two-thirds until the year 2070. At the same time, a shift of potential habitat towards the mountain tops is predicted. The multi scale approach highlights the true extent of potential habitat for this species with its patchy distribution in steep terrain. The small-scale analysis pinpoints the key habitat areas within the extensive areas of suitable habitat predicted by models on large grain sizes and in this way reveals sub-grid variability. Our results can facilitate the adaptation of species conservation strategies to a quickly changing environment.
Keywords: Species distribution modelling, Multi-scale, Climate change, Swiss Alps, Sub-grid variability
The potential for anthropogenic changes in climate has raised questions about how these changes might affect wildlife populations. We fit the Ricker population model to 25 years of data on the population sizes of white-tailed ptarmigan in Rocky Mountain National Park (RMNP), Colorado, USA, using 12 different weather variables as covariates. The best approximating model for population growth rates of the ptarmigan was selected using the Akaike information criterion and Aikaike weights. Our linear regression results suggest that median hatch dates advanced signifi- cantly from 1975 to 1999 in response to increases in April and May temperatures. Our best approxi- mating population model indicated that high winter minimum temperatures retarded the growth rate of the population. Our data also had reasonable support that high mean winter monthly minimum temperatures and high mean winter monthly maximum temperatures might lower the population growth rate of the ptarmigan. We simulated the effects of future warming on the ptarmigan popula- tion in RMNP using our best ptarmigan population model and future climate scenarios projected by the Canadian Climate Center and Hadley Centre models. Our simulation results suggested that future warming would accelerate declines in ptarmigan abundance. Although our results showed a clear population level response to variation in climate, we did not detect a density-dependent effect in the ptarmigan population, and we cannot completely explain the inverse relationship between winter temperatures and population growth rates. A process-oriented modeling approach is needed for future studies to elucidate the mechanisms of the effects of climate change on the population dynamics of the white-tailed ptarmigan.
The 2011 Red List of Italian breeding birds. The purpose of Red Lists is to assess the short-term risk of extinction in a given
taxon, and they are drafted according to guidelines produced by the IUCN. The guidelines make it possible to draft both global and regional
or sub-global lists, keeping in mind the relationship between the populations being assessed and neighbouring populations. The present
work results from the application of this methodology. It aims to update the previous Red List of breeding birds in Italy and to bridge
the methodological and temporal gap that for many years has prevented Italy from availing itself of an important tool for bird conservation
and planning. We considered a totol of 270 specie: 51.1% were classified as Least Concern (LC),9.6% as Near-Threatened (NT),
while 27.3% are in one of the three threatened categories: 2.2% Critically Endangered (CR), 8.1% Endangered (EN) and 17% Vulnerable
(VU). The data for 3.3% of the species assessed was not sufficient to assign them to a threat category, and they were thus classified as
Data Deficient (DD). Finally, three species that were classified as Regionally Extinct (RE) in the previous Red List of Breeding Birds in
Italy were confirmed as such. A total of six species were classified as Critically Endangered (CR), of which four are raptors (Lammergeier,
Egyptian Vulture, Griffon Vulture, Bonelli’s Eagle) and two are passerines (Sedge Warbler, Barred Warbler). At the level of orders,
Anseriformes is the taxon with the highest percentage of threatened or near-threatened species (55.6%), followed by Gruiformes (54.6%)
and Accipitriformes (53.8%). Unfortunately it was not possible to effectively compare the current Red List with the previous one, as there
are significant methodological differences between them. The current work follows IUCN guidelines for regional red lists, which had not
yet been drafted when the previous Red List of Breeding Birds in Italy was prepared. Nevertheless, it clearly emerges that the number of
threatened passerines increased from 21.7% to 31%. This finding may in part depend on improved knowledge about population trends in
widespread species, or it may truly reflect the worsening of the conservation status of many passerine species over the last decade. Current
knowledge on breeding birds in Italy has made it possible to classify the vast majority of the species that were assessed, in spite that
information is still limited for many species.
We compared the body mass of adult rock ptarmigan Lagopus mutus shot in autumn in the French Pyrenees (Ariège), the French Alps (Hautes-Alpes) and the Italian Alps (Province of Verbania). Mean body mass of adults was greater in the Ariège than in the Hautes-Alpes both for cocks (466 vs 433 g) and hens (429 vs 406 g), with the body mass of Italian birds being intermediate (cocks 448 g, hens 418 g). The relatively large mass of rock ptarmigan in the Pyrenees contrasts with the geographic trends found in capercaillie Tetrao urogallus and grey partridge Perdix perdix in France. For the last two species, birds in the Pyrenees are smaller than those further north. The site differences that we observed in body mass of rock ptarmigan may be related to differences in availability of high quality foods, particularly ericaceous shrubs. However, at the continental scale within Europe, the body mass of rock ptarmigan appears to be greatest in northern latitudes.
We generalize the method proposed by Gelman and Rubin (1992a) for monitoring the convergence of iterative simulations by comparing between and within variances of multiple chains, in order to obtain a family of tests for convergence. We review methods of inference from simulations in order to develop convergence-monitoring summaries that are relevant for the purposes for which the simulations are used. We recommend applying a battery of tests for mixing based on the comparison of inferences from individual sequences and from the mixture of sequences. Finally, we discuss multivariate analogues, for assessing convergence of several parameters simultaneously.
We evaluate a method for fitting models to time series of population abun-dances that incorporates both process noise and observation error in a likelihood framework. The method follows the probability logic of the Kalman filter, but whereas the Kalman filter applies to linear, Gaussian systems, we implement the full probability calculations numerically so that any nonlinear, non-Gaussian model can be used. We refer to the method as the ''numerically integrated state-space (NISS) method'' and compare it to two common methods used to analyze nonlinear time series in ecology: least squares with only process noise (LSPN) and least squares with only observation error (LSOE). We compare all three methods by fitting Beverton-Holt and Ricker models to many replicate model-generated time series of length 20 with several parameter choices. For the Ricker model we chose parameters for which the deterministic part of the model produces a stable equilibrium, a two-cycle, or a four-cycle. For each set of parameters we used three process-noise and observation-error scenarios: large standard deviation (0.2) for both, and large for one but small (0.05) for the other. The NISS method had lower estimator bias and variance than the other methods in nearly all cases. The only exceptions were for the Ricker model with stable-equilibrium parameters, in which case the LSPN and LSOE methods has lower bias when noise variances most closely met their assumptions. For the Beverton-Holt model, the NISS method was much less biased and more precise than the other methods. We also evaluated the utility of each method for model selection by fitting simulated data to both models and using information criteria for selection. The NISS and LSOE methods showed a strong bias toward selecting the Ricker over the Beverton-Holt, even when data were generated with the Beverton-Holt. It remains unclear whether the LSPN method is generally superior for model selection or has fortuitously better biases in this particular case. These results suggest that information criteria are best used with caution for nonlinear population models with short time series. Finally we evaluated the convergence of likelihood ratios to theoretical asymptotic distributions. Agreement with asymptotic distributions was very good for stable-point Rick-er parameters, less accurate for two-cycle and four-cycle Ricker parameters, and least accurate for the Beverton-Holt model. The numerically integrated state-space method has a number of advantages over least squares methods and offers a useful tool for connecting models and data and ecology.
Questions: Did the forest area in the Swiss Alps increase between 1985 and 1997? Does the forest expansion near the tree line represent an invasion into abandoned grasslands (ingrowth) or a true upward shift of the local tree line? What land cover / land use classes did primarily regenerate to forest, and what forest structural types did primarily regenerate? And, what are possible drivers of forest regeneration in the tree line ecotone, climate and/or land use change?
Location: Swiss Alps.
Methods: Forest expansion was quantified using data from the repeated Swiss land use statistics GEOSTAT. A moving window algorithm was developed to distinguish between forest ingrowth and upward shift. To test a possible climate change influence, the resulting upward shifts were compared to a potential regional tree line.
Results: A significant increase of forest cover was found between 1650 m and 2450 m. Above 1650 m, 10% of the new forest areas were identified as true upward shifts whereas 90% represented ingrowth, and we identified both land use and climate change as likely drivers. Most upward shift activities were found to occur within a band of 300 m below the potential regional tree line, indicating land use as the most likely driver. Only 4% of the upward shifts were identified to rise above the potential regional tree line, thus indicating climate change.
Conclusions: Land abandonment was the most dominant driver for the establishment of new forest areas, even at the tree line ecotone. However, a small fraction of upwards shift can be attributed to the recent climate warming, a fraction that is likely to increase further if climate continues to warm, and with a longer time‐span between warming and measurement of forest cover.
This paper provides an overview of climatic changes that have been observed during the past century at certain high-elevation sites, and changes in a more distant past documented by a variety of climate-sensitive environmental indicators, such as tree-rings and alpine glaciers, that serve as a measure of the natural variability of climate in mountains over longer time scales.
Detailed studies such as those found in this special issue of Climatic Change, as well as those noted in this review, for the mountain regions of the world, advance our understanding in a variety of ways. They are not only helpful to characterize present and past climatological features in the mountainous zones, but they also provide useful information to the climate modeling community. Because of the expected refinements in the physical parameterization of climate models in coming years, and the probable increase in the spatial resolution of GCMs, the use of appropriate data from high elevation sites will become of increasing importance for model initialization, verification, and intercomparison purposes. The necessity of accurate projections of climate change is paramount to assessing the likely impacts of climate change on mountain biodiversity, hydrology and cryosphere, and on the numerous economic activities which take place in these regions.
We examined breeding habitat selection at two scales for White-tailed (Lagopus leucura), Rock (L. muta), and Willow Ptarmigan (L. lagopus) at an alpine site in the Ruby Range Mountains of the Yukon Territory, Canada. To infer species-specific preferences, we
used logistic regression and AIC model selection to compare nest habitat of White-tailed (n=43) and Rock Ptarmigan (n=58). Only descriptive statistics were used for Willow Ptarmigan (n=8 nests) because of smaller sample sizes. Modeling results indicate elevation, slope, and the ground cover of graminoids
and lichens were the main variables separating White-tailed and Rock Ptarmigan breeding habitat. Average estimates for elevation
and slope around nest sites of each species followed a pattern of White-tailed Ptarmigan (1,827m, 30°)>Rock Ptarmigan (1,728m,
18°)>Willow Ptarmigan (1,512m, 6°). White-tailed Ptarmigan tended to select drier habitats dominated by lichens, rock and
dwarf shrubs, while Rock Ptarmigan were more common in meadows with graminoids and scattered woody shrubs. Willow Ptarmigan
nested in areas with dense, woody shrubs. The three species display inter- and intraspecific territoriality, and while species-specific
habitat preferences allow co-existence, the niche width of each is likely narrowed by the presence of congeners, particularly
for White-tailed and Rock Ptarmigan. Within territories, all three species selected nest sites with more lateral cover than
expected at random (24–50%). White-tailed and Rock Ptarmigan did not select specific cover types (vegetation or rock) for
nest sites within territories, while most Willow Ptarmigan nests were located in patches of scrub birch (Betula glandulosa).
1. The role of energy in ecological processes has hitherto been considered primarily from the standpoint that energy supply is limited. That is, traditional resource-based ecological and evolutionary theories and the recent ‘metabolic theory of ecology’ (MTE) all assume that energetic constraints operate on the supply side of the energy balance equation.
2. For endothermic animals, we provide evidence suggesting that an upper boundary on total energy expenditure is imposed by the maximal capacity to dissipate body heat and therefore avoid the detrimental consequences of hyperthermia – the heat dissipation limit (HDL) theory. We contend that the HDL is a major constraint operating on the expenditure side of the energy balance equation, and that processes that generate heat compete and trade-off within a total boundary defined by heat dissipation capacity, rather than competing for limited energy supply.
3. The HDL theory predicts that daily energy expenditure should scale in relation to body mass (Mb) with an exponent of about 0·63. This contrasts the prediction of the MTE of an exponent of 0·75.
4. We compiled empirical data on field metabolic rate (FMR) measured by the doubly-labelled water method, and found that they scale to Mb with exponents of 0·647 in mammals and 0·658 in birds, not significantly different from the HDL prediction (P > 0·05) but lower than predicted by the MTE (P < 0·001). The same statistical result was obtained using phylogenetically independent contrasts analysis. Quantitative predictions of the model matched the empirical data for both mammals and birds. There was no indication of curvature in the relationship between Loge FMR and LogeMb.
5. Together, these data provide strong support for the HDL theory and allow us to reject the MTE, at least when applied to endothermic animals.
6. The HDL theory provides a novel conceptual framework that demands a reframing of our views of the interplay between energy and the environment in endothermic animals, and provides many new interpretations of ecological and evolutionary phenomena.
The demography of vertebrate populations is governed in part by processes operating at large spatial scales that have synchronizing effects on demographic parameters over large geographic areas, and in part, by local processes that generate fluctuations that are independent across populations. We describe a statistical model for the analysis of individual monitoring data at the multi‐population scale that allows us to (1) split up temporal variation in survival into two components that account for these two types of processes and (2) evaluate the role of environmental factors in generating these two components. We derive from this model an index of synchrony among populations in the pattern of temporal variation in survival, and we evaluate the extent to which environmental factors contribute to synchronize or desynchronize survival variation among populations.
When applied to individual monitoring data from four colonies of the Atlantic Puffin ( Fratercula arctica ), 67% of between‐year variance in adult survival was accounted for by a global spatial‐scale component, indicating substantial synchrony among colonies. Local sea surface temperature (SST) accounted for 40% of the global spatial‐scale component but also for an equally large fraction of the local‐scale component. SST thus acted at the same time as both a synchronizing and a desynchronizing agent. Between‐year variation in adult survival not explained by the effect of local SST was as synchronized as total between‐year variation, suggesting that other unknown environmental factors acted as synchronizing agents.
Our approach, which focuses on demographic mechanisms at the multi‐population scale, ideally should be combined with investigations of population size time series in order to characterize thoroughly the processes that underlie patterns of multi‐population dynamics and, ultimately, range dynamics.
Treelines are temperature sensitive transition zones that are expected to respond to climate warming by advancing beyond their current position. Response to climate warming over the last century, however, has been mixed, with some treelines showing evidence of recruitment at higher altitudes and/or latitudes (advance) whereas others reveal no marked change in the upper limit of tree establishment. To explore this variation, we analysed a global dataset of 166 sites for which treeline dynamics had been recorded since 1900 AD. Advance was recorded at 52% of sites with only 1% reporting treeline recession. Treelines that experienced strong winter warming were more likely to have advanced, and treelines with a diffuse form were more likely to have advanced than those with an abrupt or krummholz form. Diffuse treelines may be more responsive to warming because they are more strongly growth limited, whereas other treeline forms may be subject to additional constraints.
Bayesian statistics has exploded into biology and its sub-disciplines, such as ecology, over the past decade. The free software program WinBUGS and its open-source sister OpenBugs is currently the only flexible and general-purpose program available with which the average ecologist can conduct standard and non-standard Bayesian statistics. Bayesian Population Analysis Using WinBUGS goes right to the heart of the matter by providing ecologists with a comprehensive, yet concise, guide to applying WinBUGS to the types of models that they use most often: linear (LM), generalized linear (GLM), linear mixed (LMM) and generalized linear mixed models (GLMM). Comprehensive and richly-commented examples illustrate a wide range of models that are most relevant to the research of a modern population ecologist. All WinBUGS/OpenBUGS analyses are completely integrated in software R. Includes complete documentation of all R and WinBUGS code required to conduct analyses and shows all the necessary steps from having the data in a text file out of Excel to interpreting and processing the output from WinBUGS in R.
Alpine treelines mark the low-temperature limit of tree growth and occur in mountains world-wide. Presenting a companion to his book Alpine Plant Life, Christian Körner provides a global synthesis of the treeline phenomenon from sub-arctic to equatorial latitudes and a functional explanation based on the biology of trees. The comprehensive text approaches the subject in a multi-disciplinary way by exploring forest patterns at the edge of tree life, tree morphology, anatomy, climatology and, based on this, modelling treeline position, describing reproduction and population processes, development, phenology, evolutionary aspects, as well as summarizing evidence on the physiology of carbon, water and nutrient relations, and stress physiology. It closes with an account on treelines in the past (palaeo-ecology) and a section on global change effects on treelines, now and in the future. With more than 100 illustrations, many of them in colour, the book shows alpine treelines from around the globe and offers a wealth of scientific information in the form of diagrams and tables.
Bayesian statistics has exploded into biology and its sub-disciplines, such as ecology, over the past decade. The free software program WinBUGS and its open-source sister OpenBugs is currently the only flexible and general-purpose program available with which the average ecologist can conduct standard and non-standard Bayesian statistics. Bayesian Population Analysis Using WinBUGS goes right to the heart of the matter by providing ecologists with a comprehensive, yet concise, guide to applying WinBUGS to the types of models that they use most often: linear (LM), generalized linear (GLM), linear mixed (LMM) and generalized linear mixed models (GLMM). Comprehensive and richly-commented examples illustrate a wide range of models that are most relevant to the research of a modern population ecologist. All WinBUGS/OpenBUGS analyses are completely integrated in software R. Includes complete documentation of all R and WinBUGS code required to conduct analyses and shows all the necessary steps from having the data in a text file out of Excel to interpreting and processing the output from WinBUGS in R.
The Alpine Rock Ptarmigan Lagopus muta helvetica is considered to be particularly vulnerable to climate warming because it lives exclusively above the tree-line in alpine habitats and is adapted to cold climates. Its Swiss population index has decreased over the last two decades. A considerable shrinkage in distributional area is predicted with further climate change. We assess whether the Alpine Rock Ptarmigan has moved to higher elevations in recent years in the Swiss Alps, and whether such elevational shifts have differed between regions and seasons, using observations recorded by volunteers over a 29-year period. The elevational shifts differed greatly between regions. In the Eastern and Southern Alps, Ptarmigans were increasingly recorded in higher elevational bands, with a mean uphill shift of 6.4 - 9.4 m/year over the last three decades, a pattern that could not be explained by the yearly variation in weather conditions, whereas there was only a moderate upward shift (1.5 – 3.2 m/year) in the Northern Alps and almost no shift in the Western Alps. Elevational changes were generally greater than those observed in other bird species. The observed upward shift in the Eastern and Southern Alps is among the fastest observed in animals and plants, and may be caused by an upward shift of the tree-line and reforestation of formerly cut or unforested areas. The observed elevational shift of the distribution of the Alpine Rock Ptarmigan has led to a reduction in the range of this subspecies, which is restricted to the Alps and isolated from other populations.This article is protected by copyright. All rights reserved.
Treelines, wherever they occur, at thermal, drought, nutritional or salt stress gradients represent an abrupt transition in life-form dominance; lines beyond which massive single stems and tall crowns either can not be developed, become un-affordable or are disadvantageous Fig. 7.1. Why do trees disappear above a certain elevation, what causes the alpine zone to be treeless, i.e. “alpine”? The answer to this question would also indicate which functional attributes alpine plants must have to be where trees are unable to be. Thus, there is a reciprocal interest in this question, upslope for forest ecology, and downslope (because of its lower boundary) for alpine ecology.
We estimated clutch size, hatching success, chick survival before independence from hens and juvenile survival after independence in Japanese rock ptarmigan Lagopus muta japonica during 2006-2012 on Mt. Norikura, Honshu, Japan. The tame behaviour of this subspecies provided us a unique opportunity to observe them at a close range throughout the period from hatching to adulthood. The average clutch size was 5.7 +/- 0.1 (+/- SE). We estimated the average hatching success to be 0.602 +/- 0.880, the average nest hatching success to be 0.733 +/- 1.071, the average hatchability of successful nests to be 0.907 +/- 0.017 and average female survival during June, as an indicator of their survival during laying and the incubation periods, to be 0.905 +/- 0.055. We attributed all egg losses to predation by carnivores. Clutch size, nest success, hatchability and female survival during June did not vary among years. Chick survival decreased sharply during the first four weeks of the brooding season. The average annual chick survival until independence was 0.278 +/- 0.097, but it varied from 0.096 +/- 0.051 to 0.639 +/- 0.084. Survival of juveniles after independence was higher than for chicks before independence. Average over-winter survival of juveniles was larger and was 0.902 +/- 0.015. We estimated the average reproductive success of Japanese rock ptarmigan from egg-laying to one year old to be 0.586 +/- 0.883 birds/breeding female. Weather conditions, especially rainfall, during the first two weeks of the brooding season appeared to negatively affect chick survival.
Climate change has resulted in upward elevational shifts in the distribution of animals and plants in many areas. The potential consequences of such changes for alpine bird communities were assessed by modelling data on breeding bird distributions along altitudinal gradients in the European Alps in relation to habitat, topography and temperature. Models were used to assess species’ sensitivity to potential future environmental change by estimating distributions under a range of scenarios of habitat and climate change, thereby identifying likely future conservation priorities. Distributions of the majority of forest or shrub species remained stable or increased in response to climate change as a result of elevational shifts in suitable habitats. However, open habitat species may face a severe decrease in distribution as grasslands are colonised by forest and shrubs, because much of the area considered is not at a sufficient altitude to accommodate further elevational shifts. This may be exacerbated if vegetation development is constrained at high altitudes, leading to a habitat ‘squeeze’ caused by an asymmetric response of vegetation zones to climate change. These results suggest that grassland species may be of conservation concern in the future, and that management strategies to maintain openness should be prioritised. However, model outcomes also suggested such management may not be sufficient for a number of species if climate change results in a mismatch between the distribution of suitable climates and suitable habitats. The loss of open habitats may therefore present a serious conservation problem for mountain biodiversity in the future.
We describe a discrete-time, stochastic population model with density depend- ence, environmental-type process noise, and lognormal observation or sampling error. The model, a stochastic version of the Gompertz model, can be transformed into a linear Gaussian state-space model (Kalman filter) for convenient fitting to time series data. The model has a multivariate normal likelihood function and is simple enough for a variety of uses ranging from theoretical study of parameter estimation issues to routine data analyses in population monitoring. A special case of the model is the discrete-time, stochastic exponential growth model (density independence) with environmental-type process error and lognormal observation error. We describe two methods for estimating parameters in the Gompertz state-space model, and we compare the statistical qualities of the methods with computer simulations. The methods are maximum likelihood based on observations and restricted maximum likelihood based on first differences. Both offer adequate statistical properties. Because the likelihood function is identical to a repeated-measures analysis of variance model with a random time effect, parameter estimates can be calculated using PROC MIXED of SAS. We use the model to analyze a data set from the Breeding Bird Survey. The fitted model suggests that over 70% of the noise in the population's growth rate is due to observation error. The model describes the autocovariance properties of the data especially well. While observation error and process noise variance parameters can both be estimated from one time series, multimodal likelihood functions can and do occur. For data arising from the model, the statistically consistent parameter estimates do not necessarily correspond to the global maximum in the likelihood function. Maximization, simulation, and bootstrapping programs must accommodate the phenomenon of multimodal likelihood functions to produce statistically valid results.
Estimation of density dependence from time series data on population abundance is hampered in the presence of observation or measurement errors. Fitting state-space models has been proposed as a solution that reduces the bias in estimates of density dependence caused by ignoring observation errors. While this is often true, I show that, for specific parameter values, there are identifiability issues in the linear state-space model when the strength of density dependence and the observation and process error variances are all unknown. Using simulation to explore properties of the estimators, I illustrate that, unless assumptions are imposed on the process or observation error variances, the variance of the estimator of density dependence varies critically with the strength of the density dependence. Under compensatory dynamics, the stronger the density dependence the more difficult it is to estimate in the presence of observation errors. The identifiability issues disappear when density dependence is estimated from the state-space model with the observation error variance known to the correct value. Direct estimates of observation variance in abundance censuses could therefore prove helpful in estimating density dependence but care needs to be taken to assess the uncertainty in variance estimates.
The degree of synchrony between populations is critical for their dynamics at large spatial scales. Population synchrony has been assessed for only a few species of vertebrates, most of them have largely fluctuating populations with multiannual cycles. We investigated the intensity and spatial extent of synchrony among populations of birds in Britain. The data analyzed ran from 1962 to 1995 at more than 1000 local sites and concerned 60 species. For each species, we measured the intensity of synchrony among local populations using the cross-correlation function (CCF) and assessed its spatial extent. We tested for differences in these two measures with respect to habitat. We also assessed the potential influence of long-term trends in population synchrony. By aggregating the sites in regions and estimating an index for each region, we measured synchrony at a large spatial scale. In general, we found that synchrony was low between populations of British birds. All but one species with the strongest level of synchrony show a pronounced long-term decline. The mean CCF was significantly correlated with the mean abundance of each species in the Common Birds Census (CBC) sites, suggesting that the more abundant species have more synchronous populations. Significant differences in synchrony between habitats were found in 25 species; synchrony was stronger in farmlands compared to woodlands for 22 species. The same result was observed both at the intra- and interspecific levels. This may be the result of national change in agricultural practice affecting all farmland populations. Our cross-scale analysis showed that synchrony is a scale-dependent phenomenon. Our study is the first to focus on a large number of 'noncyclic' species, and it suggests that synchrony is weaker for these species than for those with widely fluctuating cyclic populations. This is in agreement with some studies on synchrony of insects. Synchrony in natural populations seems to be determined by complex interactions between abundance, population variability, species characteristics, and demographic mechanisms. A general pattern emerging from our study and others is that population synchrony is more intense during declines.
We generalize the method proposed by Gelman and Rubin (1992a) for monitoring the convergence of iterative simulations by comparing between and within variances of multiple chains, in order to obtain a family of tests for convergence. We review methods of inference from simulations in older to develop convergence-monitoring summaries that are relevant for the purposes for which the simulations are used. We recommend applying a battery of tests for mixing based on the comparison of inferences from individual sequences and from the mixture of sequences. Finally, we discuss multivariate analogues, for assessing convergence of several parameters simultaneously.
A central question in population ecology is how to estimate the effects of common environmental noise, e.g. due to large‐scale climate patterns, on the synchrony in population fluctuations over large distances. We show how the environmental variance can be split into components generated by several environmental variables and how these can be estimated from time‐series observations.
With a set of time‐series observations from different locations not necessarily covering the same time span, it is shown how the spatial autocorrelation of the residual variance component, not explained by the covariates and corrected for demographic stochasticity, can be estimated using classical multinormal theory.
Some previous results on spatial scaling in continuous linearized models on log scale are extended to also provide the scaling for the residuals. This is shown to be close to the spatial scaling of the autocorrelation in the environmental noise and only weakly affected by migration.
The logistic model of local population dynamics with the NAO index as the only covariate is fitted to 22 populations of the Continental great cormorant Phalacrorax carbo sinensis . The spatial scale of the environmental noise is estimated to be about 155 km. The NAO index alone accounts for about 10% of the total environmental variance and nearly all of the regional environmental variance (long‐distance environmental autocorrelation).
1. Human outdoor recreational activities are increasing and have a significant impact on wildlife. There are few methods suitable for investigating the response of rare and endangered species to human recreational activities, although the impact can be assessed at various scales by measuring both physiological and behavioural responses to disturbance.
2. Capercaillie Tetrao urogallus are suffering strong population declines throughout central Europe. We examined the effects of ski tourism on capercaillie habitat use and adrenocortical activity, measured non-invasively in droppings.
3. During three winters, 2003–06, we radio-tracked 13 capercaillie. In the southern Black Forest in Germany, we sampled 396 droppings of these and additional individuals before and after the start of the ski season. We tested whether the intensity of human winter recreational activities affected home range location and habitat use, and we identified those factors influencing the concentration of corticosterone metabolites (CM) in droppings.
4. Capercaillie used habitats subject to ski tourism. Although the latter did not affect home range location, capercaillie preferred undisturbed forests within their home ranges and avoided areas with high recreation intensity in the ski season. Faecal CM levels of individuals in areas with low recreation intensity were significantly lower than those in areas with moderate or high recreation intensity during the entire study period.
5. We conclude that ski tourism affects both habitat use and endocrine status in capercaillie, with potential negative consequences on body condition and overall fitness.
6. Synthesis and applications.
This study demonstrates the relevance of studying wildlife responses at various temporal and spatial scales, and the value of using multiple methods applied to the same individuals to monitor the impact of human recreational activities on a free-ranging species. In order to protect capercaillie populations, we recommend that managers keep forests inhabited by capercaillie free from tourism infrastructure and retain undisturbed forest patches within skiing areas.
Understanding the effects of climate on avian life history traits is essential if we wish to predict the demographic consequences of expected climatic changes. We investigated the influence of weather conditions on the reproductive success of Rock Ptarmigan Lagopus muta in the eastern French Pyrenees, one of the southernmost areas inhabited by the species. Reproductive success was estimated in early August between 1997 and 2006 by counting adults and well-grown chicks with pointing dogs. The number of young per adult varied from 0.08 to 0.72. Using Poisson regression and Akaike's information criterion, we selected the best model explaining the effect of weather (date of snowmelt and, for both laying/incubation and post-hatching periods, mean minimum and maximum temperatures, monthly rainfall and number of days with rain) on the proportion of young in August. Reproductive success was positively associated with early appearance of snow-free ground, and date of snowmelt alone was the model that best explained annual variation in reproductive success. Other models, which included a negative effect of rainfall, particularly after hatching, also had some support. Hence, both pre-laying and post-hatching weather conditions influenced reproductive success of Rock Ptarmigan in the eastern French Pyrenees. On a continental scale, reproductive success of alpine populations of Rock Ptarmigan is consistently lower than that of northern populations. This difference in productivity may be partly correlated with climatic conditions observed along an arctic–alpine gradient, the amount and variation of rainfall being greater in southern alpine areas than elsewhere in the species’ range.
1.1. Standard metabolic rate of 48·8 kcal/24 hr for the white-tailed ptarmigan (Lagopus leucurus) is slightly higher than expected and may be associated with the continuous molt in this species.2.2. The lower critical temperature (6·5–11·5°C) is one of the lowest values recorded for birds and reflects the ptarmigan's excellent insulation.3.3. The ptarmigan has the lowest evaporative efficiency recorded in birds. Differences in efficiency of evaporative cooling may be adaptive, since they are correlated with habitat.4.4. Ambient temperature may be an important factor in habitat selection in some cases.
JAGS is a program for Bayesian Graphical modelling which aims for compatibility with Classic BUGS. The program could eventually be developed as an R package. This article explains the motivations for this program, briefly describes the architecture and then discusses some ideas for a vectorized form of the BUGS language.
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