| 1. |
- Fucini, Stefania, et al.
(författare)
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Geographic variation in air temperature leads to intraspecific variability in the behavior and productivity of a eusocial insect
- 2014
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Ingår i: Journal of insect behavior. - : Springer. - 0892-7553 .- 1572-8889. ; 27:3, s. 403-410
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Tidskriftsartikel (refereegranskat)abstract
- In primitively eusocial insects, air temperature is the environmental factor that primarily affects colony cycle. Several studies demonstrated interspecific differences in the adaptation of eusocial insects to local air temperature. Nevertheless, studies on intraspecific adaptations are rare. In this study, we investigate the influence of air temperature on local adaptations in behavior and colony productivity of Polistes biglumis foundresses living in warm and cold temperate zones. We hypothesized that foundresses from warm temperate zones would show a higher activity level compared to those from cold temperate zones before brood emergence, based on differences in air temperature between the two zones. After brood emergence, we expected a reduced foundress activity level in the warm climate zone, due to workers’ help. In contrast, foundresses living in the cold-climate zone, which do not produce workers, were expected to remain active throughout the nesting season. We also hypothesized that colony productivity was higher in warm-climate colonies. As expected, warm-climate foundresses reduced their activity level after brood emergence and, with their relatively large number of workers, continued egg production throughout the nesting season. Further studies are necessary to assess if these intraspecific differences are attributable to phenotypic plasticity or genetic divergence.
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| 2. |
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| 3. |
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| 4. |
- Uboni, Alessia, et al.
(författare)
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Can management buffer pasture loss and fragmentation for Sami reindeer herding in Sweden?
- 2020
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Ingår i: Pastoralism. - : Springer. - 2041-7136. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Today, climate change and competing land use practices are threatening rangelands around the world and the pastoral societies that rely on them. Reindeer husbandry practised by the indigenous Sami people is an example. In Sweden, approximately 70% of the most productive lichen pastures (important in winter) has been lost, either completely or because of a reduction in forage quality, as a result of competing land use (primarily commercial forestry). The remaining pastures are small and fragmented. Yet, the number of reindeer in Sweden shows no general decline. We investigated the strategies that have allowed reindeer herders to sustain their traditional livelihood despite a substantial loss of pastures and thus natural winter forage for their reindeer. Changes in harvest strategy and herd structure may partially explain the observed dynamics, and have increased herd productivity and income, but were not primarily adopted to counteract forage loss. The introduction of supplementary feeding, modern machinery, and equipment has assisted the herders to a certain extent. However, supplementary feeding and technology are expensive. In spite of governmental support and optimized herd productivity and income, increasing costs provide low economic return. We suggest that the increased economical and psychosocial costs caused by forage and pasture losses may have strong effects on the long-term sustainability of reindeer husbandry in Sweden.
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| 6. |
- Uboni, Alessia, et al.
(författare)
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Interannual variability : a crucial component of space use at the territory level
- 2015
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Ingår i: Ecology. - : Wiley-Blackwell. - 0012-9658 .- 1939-9170. ; 96:1, s. 62-70
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Tidskriftsartikel (refereegranskat)abstract
- Interannual variability in space use and how that variation is influenced by density-dependent and density-independent factors are important processes in population ecology. Nevertheless, interannual variability has been neglected by the majority of space use studies. We assessed that variation for wolves living in 15 different packs within Yellowstone National Park during a 13-year period (1996–2008). We estimated utilization distributions to quantify the intensity of space use within each pack's territory each year in summer and winter. Then, we used the volume of intersection index (VI) to quantify the extent to which space use varied from year to year. This index accounts for both the area of overlap and differences in the intensity of use throughout a territory and ranges between 0 and 1. The mean VI index was 0.49, and varied considerably, with ~20% of observations (n = 230) being <0.3 or >0.7. In summer, 42% of the variation was attributable to differences between packs. These differences can be attributable to learned behaviors and had never been thought to have such an influence on space use. In winter, 34% of the variation in overlap between years was attributable to interannual differences in precipitation and pack size. This result reveals the strong influence of climate on predator space use and underlies the importance of understanding how climatic factors are going to affect predator populations in the occurrence of climate change. We did not find any significant association between overlap and variables representing density-dependent processes (elk and wolf densities) or intraspecific competition (ratio of wolves to elk). This last result poses a challenge to the classic view of predator–prey systems. On a small spatial scale, predator space use may be driven by factors other than prey distribution.
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| 7. |
- Uboni, Alessia, et al.
(författare)
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Long- and short-term temporal variability in habitat selection of a top predator
- 2015
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Ingår i: Ecosphere. - : Ecological Society of America. - 2150-8925. ; 6:4
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Tidskriftsartikel (refereegranskat)abstract
- Considerable theory explains the importance of understanding temporal variation in ecological processes. Nevertheless, long-term variability in habitat selection is rarely assessed or even acknowledged. We explored temporal variability in the habitat selection of a top-predator, the wolf (Canis lupus), at two time scales: interannual and seasonal variability. To do this, we developed resource utilization functions to relate wolf habitat selection to environmental variables in different years and seasons. We used radiotelemetry data collected from a wolf population in Yellowstone National Park during a 10-year period (1998-2007) and added a Year variable in the models to account for interannual variation in the studied processes. We also used a three-year data set (nested within the 10-year data set) to incorporate additional variables in the models and test for differences in short- and long-term patterns of habitat selection. Wolves exhibited seasonal variation in habitat selection with respect to distance from roads, elevation, openness, and habitat type. Habitat selection was considerably more complicated during the winter compared to summer, when wolves only selected habitat based on distance from roads. We detected clear patterns of habitat selection in the three-year data set that could not be detected in the 10-year data set, despite the longer data set had more statistical power for pattern detection. This observation is likely the result of the longer data set being comprised of several shorter-term and countervailing patterns. This explanation is also consistent with having detected significant year effects in the 10-year data set. Insomuch as habitat selection is important to conservation and management, this research is significant for demonstrating the different impressions that can be given by short-term and long-term studies. It may be common for short-term data sets to suggest patterns of habitat selection that do not prevail over longer periods of time.
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| 8. |
- Uboni, Alessia, et al.
(författare)
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Long-Term Trends and Role of Climate in the Population Dynamics of Eurasian Reindeer
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- Temperature is increasing in Arctic and sub-Arctic regions at a higher rate than anywhere else in the world. The frequency and nature of precipitation events are also predicted to change in the future. These changes in climate are expected, together with increasing human pressures, to have significant impacts on Arctic and sub-Arctic species and ecosystems. Due to the key role that reindeer play in those ecosystems, it is essential to understand how climate will affect the region's most important species. Our study assesses the role of climate on the dynamics of fourteen Eurasian reindeer (Rangifer tarandus) populations, using for the first time data on reindeer abundance collected over a 70-year period, including both wild and semi-domesticated reindeer, and covering more than half of the species' total range. We analyzed trends in population dynamics, investigated synchrony among population growth rates, and assessed the effects of climate on population growth rates. Trends in the population dynamics were remarkably heterogeneous. Synchrony was apparent only among some populations and was not correlated with distance among population ranges. Proxies of climate variability mostly failed to explain population growth rates and synchrony. For both wild and semi-domesticated populations, local weather, biotic pressures, loss of habitat and human disturbances appear to have been more important drivers of reindeer population dynamics than climate. In semi-domesticated populations, management strategies may have masked the effects of climate. Conservation efforts should aim to mitigate human disturbances, which could exacerbate the potentially negative effects of climate change on reindeer populations in the future. Special protection and support should be granted to those semi-domesticated populations that suffered the most because of the collapse of the Soviet Union, in order to protect the livelihood of indigenous peoples that depend on the species, and the multi-faceted role that reindeer exert in Arctic ecosystems.
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| 9. |
- Uboni, Alessia, et al.
(författare)
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Modelling occurrence and status of mat-forming lichens in boreal forests to assess the past and current quality of reindeer winter pastures
- 2019
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Ingår i: Ecological Indicators. - : Elsevier. - 1470-160X .- 1872-7034. ; 96, s. 99-106
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Tidskriftsartikel (refereegranskat)abstract
- Lichens play an essential role in northern ecosystems as important contributors to the water, nutrient and carbon cycles, as well as the main winter food resource for reindeer (Rangifer tarandus, also called caribou in North America), the most abundant herbivores in arctic and subarctic regions. Today, climate change and several types of land use are rapidly transforming northern ecosystems and challenging lichen growth. Since lichens are important indicators of ecosystem health and habitat suitability for reindeer, large-scale assessments are needed to estimate their past, present and future status. In our study, we aimed to develop models and equations that can be used by stakeholders to identify the occurrence of lichen-dominated boreal forests and to determine lichen conditions in those forests. Data were collected in Sweden and most input data are publicly available. We focused on mat-forming lichens belonging to the genera Cladonia and Cetraria, which are dominant species in the reindeer and caribou winter diet. Our models described lichen-dominated forests as being dominated by Scots pine (Pines sylvestris), having low basal area and thin canopy cover, and being located in south-and west-facing areas with high summer precipitation, low winter precipitation and temperature, and on gentle slopes. Within those forests, lichen biomass was positively related to tree canopy cover and summer precipitation, while negatively and exponentially related to intensity of use of the area by reindeer. Forest, meteorological, topographic and soil data can be used as input in our models to determine lichen conditions without having to estimate lichen biomass through demanding and expensive fieldwork.
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