Swiss National Park

Zernez, Switzerland

Swiss National Park

Zernez, Switzerland

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Risch A.C.,Swiss Federal Institute of forest | Haynes A.G.,Swiss Federal Institute of forest | Busse M.D.,U.S. Department of Agriculture | Filli F.,Swiss National Park | Schutz M.,Swiss Federal Institute of forest
Ecosystems | Year: 2013

Grasslands support large populations of herbivores and store up to 30% of the world's soil carbon (C). Thus, herbivores likely play an important role in the global C cycle. However, most studies on how herbivory impacts the largest source of C released from grassland soils-soil carbon dioxide (CO2) emissions-only considered the role of large ungulates. This ignores all other vertebrate and invertebrate herbivores and their collective effects on ecosystem properties. We progressively excluded large, medium, and small vertebrates and invertebrates from two subalpine grasslands (productive, heavily grazed short-grass; less productive, lightly grazed tall-grass) using size-selective fences, assessed the impact on soil CO2 emissions and related biotic and abiotic variables. Exclusion resulted in significant changes in soil CO2 emissions in both vegetation types. Short-grass soil CO2 emissions progressively increased when large and medium mammals were excluded. However, no difference was detected among plots were all or no herbivores grazed. In contrast, tall-grass soil CO2 emissions were not affected by mammal exclusion, but excluding all herbivores lead to reduced emissions. Soil micro-climatic parameters best predicted the patterns of soil CO2 emissions in short-grass vegetation, whereas root biomass was the best predictor of CO2 release in tall-grass vegetation. Our results showed that diverse herbivore communities affect soil respiration differently than assumed from previous studies that only excluded large ungulates. Such information is important if we are to understand how changes in herbivore species composition-as could happen through altered management practices, extinction or invasion-impact grassland C storage and release. © 2013 Springer Science+Business Media New York.


Kneubuhler M.,University of Zürich | Damm A.,University of Zürich | Schweiger A.-K.,Swiss National Park | Risch A.C.,Swiss Federal Institute of forest | And 2 more authors.
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014

Remote sensing offers an objective and efficient way to monitor ecosystem properties including their spatial variability across different land cover types. Especially, the representation of gradients of biochemical and structural properties of ecosystems using continuous fields (CF) approaches bears advantages compared to discrete land cover classification schemes. This paper presents a concept to synergistically generate CF maps of an alpine ecosystem parameter, i.e., total surface water content, from imaging spectrometer (IS) data. Further, the potential of linking such maps to ecological patterns, i.e., the spatial distribution of large ungulates is being assessed. In vegetated areas, total surface water content is considered as a surrogate of plant physiological status. Water is, besides temperature, light, or nutrients, an important limiting growth factor determining biomass production and therefore potential animal forage quantity in alpine grasslands. Resource ecology interested in trophic interactions between large ungulates and their forage requires spatial and temporal information on ecosystem properties and processes. The study area is located in the upper Trupchun Valley (Val Trupchun) in the Swiss National Park (SNP). The valley is famous for its high densities of chamois (Rupicapra rupicapra L.), ibex (Capra ibex L.), and red deer (Cervus elaphus L.). CF maps of total surface water content were derived from Airborne Prism EXperiment (APEX) IS data collected over the SNP in June 2010 and 2011. Abundance maps of predominant land cover classes were derived from linear spectral mixture analysis (SMA). They were then combined with water content information of the respective land cover originating from either empirically or physically based approaches. The resulting CF maps depicted a spatially continuous representation of relative total surface water content. APEX IS data from two consecutive seasons revealed differences in total surface water content in June 2010 and 2011, predominantly related to an advanced phenological development in spring 2011 and to considerable differences in snow cover between the 2 years. Linking total surface water content of grasslands to observed ungulates spatial distributions did not reveal any statistically significant patterns of habitat use. We conclude that water availability in Val Trupchun may not be the dominant limiting factor for potential forage quantity (biomass), or that ungulates choose their grazing sites based on other criteria, i.e., high nutritious quality (P, N). Nevertheless, multitemporal CF maps derived from APEX IS data were found to provide spatially explicit and fine-scaled information for analyses of an ecosystem's total surface water content. The combination of multitemporal CF maps of a wide range of ecosystem parameters and more accurate and extensive observations of animal habitat use will contribute to ongoing and future vegetation-ungulates research in the SNP. © 2014 IEEE.


Rehnus M.,Swiss Federal Institute of forest | Rehnus M.,University of Natural Resources and Life Sciences, Vienna | Marconi L.,University of Neuchatel | Hacklander K.,University of Natural Resources and Life Sciences, Vienna | Filli F.,Swiss National Park
Hystrix | Year: 2013

The mountain hare Lepus timidus (Linnaeus, 1758) is one of the smallest mammals in Alpine environments that stays active year-round without any conspicuous physiological adaptations. Mountain hares thus need to respond to seasonal changes by adaptive habitat and diet choice. We studied seasonal changes in habitat use and feeding strategy in the continental Central Alps during one year. Monitoring of the presence and density of dung and microhistological analysis of faecal pellets revealed that forest habitats, particularly mountain pine shrubs (Pinus mugo ssp.), were used throughout the year, whilst open habitats were avoided during snow-covered seasons. The probabilities of pellet presence and density were positively correlated with the proportion of trees and grass in spring, summer and autumn whereas in winter, they correlated only with the proportion of trees. The observed patterns can be explained by the importance of shelter and food availability which change seasonally and especially due to snow cover. We concluded that the availability of shelter was more important than food because hares selected habitat types that offered security from predators rather than habitat types with high food quality. © 2013 Associazione Teriologica Italiana.


PubMed | Swiss National Park, University of Zürich and Swiss Federal Institute of forest
Type: | Journal: Movement ecology | Year: 2016

The spatial distribution of forage resources is a major driver of animal movement patterns. Understanding where animals forage is important for the conservation of multi-species communities, since interspecific competition can emerge if different species use the same depletable resources. However, determining forage resources in a spatially continuous fashion in alpine grasslands at high spatial resolution was challenging up to now, because terrain heterogeneity causes vegetation characteristics to vary at small spatial scales, and methods for detection of behavioural phases in animal movement patterns were not widely available. We delineated areas coupled to the foraging behaviour of three sympatric ungulate species (chamois, ibex, red deer) using Time Local Convex Hull (T-LoCoH), a non-parametric utilisation distribution method incorporating spatial and temporal autocorrelation structure of GPS data. We used resource maps of plant biomass and plant nitrogen content derived from high-resolution airborne imaging spectroscopy data, and multinomial logistic regression to compare the foraging areas of the three ungulate species.We found significant differences in plant biomass and plant nitrogen content between the core foraging areas of chamois, ibex and red deer. Core foraging areas of chamois were characterised by low plant biomass and low to medium plant nitrogen content. Core foraging areas of ibex were, in contrast, characterised by high plant nitrogen content, but varied in plant biomass, and core foraging areas of red deer had high plant biomass, but varied in plant nitrogen content.Previous studies carried out in the same study area found no difference in forage consumed by chamois, ibex and red deer. Methodologically, those studies were based on micro-histological analysis of plant fragments identifying them to plant family or functional type level. However, vegetation properties such as productivity (biomass) or plant nutrient content can vary within vegetation communities, especially in highly heterogeneous landscapes. Thus, the combination of high spatial resolution resource maps with a utilisation distribution method allowing to generate behavioural maps (T-LoCoH) provides new insights into the foraging ecology of the three sympatric species, important for their conservation and to monitor expected future changes.


News Article | February 15, 2017
Site: www.eurekalert.org

In order to restore tropical rainforests, it is not enough to simply set up protected areas and leave them to their own devices. In particular, tree species with large fruit and seeds distributed by birds will have to be actively planted. This is one of the conclusions of a large-scale study by scientists from ETH Zurich in the Western Ghats, the mountain range running along the western coast of India. Today, the rainforest that exists there is highly fragmented. In the late 20th century in particular, large areas fell victim to intensive logging and commercial agriculture such as coffee and tea plantations. Working with Indian colleagues, the ETH researchers investigated how well trees from rainforest fragments could spread to areas that had previously been cleared or logged but are now back under forest cover. At the heart of their study was the white cedar (Dysoxylum malabaricum), a tropical species belonging to the mahogany family. "These rainforest giants tower above the other trees and therefore occupy an important ecological niche," says Chris Kettle, a scientist at ETH Zurich's Institute of Terrestrial Ecosystems, who led the study. The seeds don't fall far from the tree The tree's seeds are distributed primarily by a specific species of hornbill, the Malabar grey hornbill, which eats the fleshy, fig-sized fruit and then excretes the seeds. Until now, it was not known how far the hornbills carry the seeds in their bodies. Theoretically, as the birds cover long distances, they could contribute to a rapid distribution of the tree species over a large area. This is not the case, however, as the ETH researchers have now discovered. Through genetic maternity testing of seedlings and adult trees, they were able to show that generally the seedlings grow no more than 200 metres from the mother tree, and in many cases at a distance of just 40 to 100 metres. "We suspect that the hornbills regurgitate the seeds relatively close to the tree from which they fed, so that they don't have to fly with their stomachs full of heavy seeds," says ETH doctoral student Sascha Ismail, first author of the study published in the journal New Phytologist. The results of the research have implications for the restoration of rainforests: "It is highly unlikely that the tree species we studied is able to recolonise cleared patches in a fragmented habitat by natural seed dispersal alone," says Kettle. He adds that the same applies to other endangered species of tropical tree with large fruit and seeds dispersed by birds, as evidence from other fragmented tropical forests around the world shows that seeds of this kind are dispersed only locally. "For rainforest restoration projects to be successful, you have to give special attention to these trees," says Kettle. "If you want to encourage them to spread, the only option is to collect their seeds, set up tree nurseries and then actively plant out the saplings at a later stage." For the parentage analysis, the researchers surveyed exhaustively an area covering 216 km2 (considerably larger than the area of the Swiss National Park). They analysed the DNA of all 235 adult trees found there, as well as of 448 seedlings. "This is the largest study of its kind ever carried out in a fragmented tropical ecosystem," says Kettle. Ismail S, Ghazoul J, Ravikanth G, Kushalappa CG, Shaanker RU, Kettle CJ: Evaluating realized seed dispersal across fragmented tropical landscapes: a two-fold approach using parentage analysis and the neighbourhood model. New Phytologist 2017, doi: 10.1111/nph.14427


PubMed | CNRS Alpine Ecology Laboratory, Swiss National Park, Office National de la Chasse et de la Faune Sauvage ONCFS and Norwegian University of Science and Technology
Type: Journal Article | Journal: Oecologia | Year: 2015

In many species, population dynamics are shaped by age-structured demographic parameters, such as survival, which can cause age-specific sensitivity to environmental conditions. Accordingly, we can expect populations with different age-specific survival to be differently affected by environmental variation. However, this hypothesis is rarely tested at the intra-specific level. Using capture-mark-recapture models, we quantified age-specific survival and the extent of annual variations in survival of females of alpine chamois in two sites. In one population, survival was very high (>0.94; Bauges, France) until the onset of senescence at approximately 7 years old, whereas the two other populations (Swiss National Park, SNP) had a later onset (12 years old) and a lower rate of senescence. Senescence patterns are therefore not fixed within species. Annual variation in survival was higher in the Bauges (SD = 0.26) compared to the SNP populations (SD = 0.20). Also, in each population, the age classes with the lowest survival also experienced the largest temporal variation, in accordance with inter-specific comparisons showing a greater impact of environmental variation on these age classes. The large difference between the populations in age-specific survival and variation suggests that environmental variation and climate change will affect these populations differently.


News Article | February 15, 2017
Site: phys.org

In order to restore tropical rainforests, it is not enough to simply set up protected areas and leave them to their own devices. In particular, tree species with large fruit and seeds distributed by birds will have to be actively planted. This is one of the conclusions of a large-scale study by scientists from ETH Zurich in the Western Ghats, the mountain range running along the western coast of India. Today, the rainforest that exists there is highly fragmented. In the late 20th century in particular, large areas fell victim to intensive logging and commercial agriculture such as coffee and tea plantations. Working with Indian colleagues, the ETH researchers investigated how well trees from rainforest fragments could spread to areas that had previously been cleared or logged but are now back under forest cover. At the heart of their study was the white cedar (Dysoxylum malabaricum), a tropical species belonging to the mahogany family. "These rainforest giants tower above the other trees and therefore occupy an important ecological niche," says Chris Kettle, a scientist at ETH Zurich's Institute of Terrestrial Ecosystems, who led the study. The seeds don't fall far from the tree The tree's seeds are distributed primarily by a specific species of hornbill, the Malabar grey hornbill, which eats the fleshy, fig-sized fruit and then excretes the seeds. Until now, it was not known how far the hornbills carry the seeds in their bodies. Theoretically, as the birds cover long distances, they could contribute to a rapid distribution of the tree species over a large area. This is not the case, however, as the ETH researchers have now discovered. Through genetic maternity testing of seedlings and adult trees, they were able to show that generally the seedlings grow no more than 200 metres from the mother tree, and in many cases at a distance of just 40 to 100 metres. "We suspect that the hornbills regurgitate the seeds relatively close to the tree from which they fed, so that they don't have to fly with their stomachs full of heavy seeds," says ETH doctoral student Sascha Ismail, first author of the study published in the journal New Phytologist. The results of the research have implications for the restoration of rainforests: "It is highly unlikely that the tree species we studied is able to recolonise cleared patches in a fragmented habitat by natural seed dispersal alone," says Kettle. He adds that the same applies to other endangered species of tropical tree with large fruit and seeds dispersed by birds, as evidence from other fragmented tropical forests around the world shows that seeds of this kind are dispersed only locally. "For rainforest restoration projects to be successful, you have to give special attention to these trees," says Kettle. "If you want to encourage them to spread, the only option is to collect their seeds, set up tree nurseries and then actively plant out the saplings at a later stage." For the parentage analysis, the researchers surveyed exhaustively an area covering 216 km2 (considerably larger than the area of the Swiss National Park). They analysed the DNA of all 235 adult trees found there, as well as of 448 seedlings. "This is the largest study of its kind ever carried out in a fragmented tropical ecosystem," says Kettle. Explore further: The mystery of monodominance—how natural monocultures evolve in the rainforest More information: Sascha A. Ismail et al, Evaluating realized seed dispersal across fragmented tropical landscapes: a two-fold approach using parentage analysis and the neighbourhood model, New Phytologist (2017). DOI: 10.1111/nph.14427


Corlatti L.,University of Vienna | Corlatti L.,University of Siena | Lebl K.,University of Veterinary Medicine Vienna | Filli F.,Swiss National Park | Ruf T.,University of Veterinary Medicine Vienna
Mammalian Biology | Year: 2012

Many polygynous ungulates show higher mortality of males than of females, because of the intense male-male competition during the rut and the costs associated with the development of sexual-size dimorphism. In the weakly dimorphic Alpine chamois Rupicapra rupicapra the occurrence of differential sex-specific survival strategies is controversial. To date, only two studies investigated the survivorship of males and females in this species, producing conflicting results: these works, based on the use of life tables, require confirmation from researches carried out on living populations. We assessed the survival pattern of a protected Alpine chamois population in the Swiss National Park, where 116 individuals were marked and monitored over 13 years (1996-2008). We tested for sex-, age- and year-dependence of survival by means of capture-mark-resight models. Resighting probabilities were sex-dependent, and survival rates were time-dependent. Females had higher resighting probabilities (0.84) than males (0.74). All over the time periods, sex had a weak influence on survival probability (males = 0.91; females = 0.92) and survival rates remained surprisingly high until late age (1 year = 0.90; 2-7 years = 0.91; 8+ years = 0.92). The growing evidence for a high adult survival and a weak differential mortality of the two sexes, together with the highly seasonal sexual-size dimorphism observed for Alpine chamois, might indicate the occurrence of a unique conservative survival strategy in both sexes and a low-risk mating strategy by males. © 2011 Deutsche Gesellschaft fur Saugetierkunde.


Anderwald P.,Swiss National Park | Haller R.M.,Swiss National Park | Filli F.,Swiss National Park
PLoS ONE | Year: 2016

Habitat heterogeneity can promote coexistence between herbivores of different body size limited to different extents by resource quantity and quality. Red deer (Cervus elaphus) are known as superior competitors to smaller species with similar diets. We compared competitive interactions and habitat use between red deer and Alpine chamois (Rupicapra rupicapra) in two adjacent valleys in a strictly protected area in the Central Alps. Red deer density was higher in the valley with higher primary productivity. Only here was horn growth in kid and yearling chamois (as a measure for body condition) negatively correlated with red deer population size, suggesting interspecific competition, and chamois selected meadows with steeper slopes and lower productivity than available on average. Conversely, red deer selected meadows of high productivity, particularly in the poorer area. As these were located mainly at lower elevations, this led to strong altitudinal segregation between the two species here. Local differences in interspecific competition thus coincided with differences in habitat preference and-segregation between areas. This suggests that spatial habitat and resource heterogeneity at the scale of adjacent valleys can provide competition refuges for competitively inferior mountain ungulates which differ from their superior competitor in their metabolic requirements. © 2016 Anderwald et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


PubMed | Swiss National Park
Type: Journal Article | Journal: PloS one | Year: 2016

Habitat heterogeneity can promote coexistence between herbivores of different body size limited to different extents by resource quantity and quality. Red deer (Cervus elaphus) are known as superior competitors to smaller species with similar diets. We compared competitive interactions and habitat use between red deer and Alpine chamois (Rupicapra rupicapra) in two adjacent valleys in a strictly protected area in the Central Alps. Red deer density was higher in the valley with higher primary productivity. Only here was horn growth in kid and yearling chamois (as a measure for body condition) negatively correlated with red deer population size, suggesting interspecific competition, and chamois selected meadows with steeper slopes and lower productivity than available on average. Conversely, red deer selected meadows of high productivity, particularly in the poorer area. As these were located mainly at lower elevations, this led to strong altitudinal segregation between the two species here. Local differences in interspecific competition thus coincided with differences in habitat preference and-segregation between areas. This suggests that spatial habitat and resource heterogeneity at the scale of adjacent valleys can provide competition refuges for competitively inferior mountain ungulates which differ from their superior competitor in their metabolic requirements.

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