| 1. |
- Horstkotte, Tim, 1981-, et al.
(author)
-
Successional pathways of terrestrial lichens in changing Swedish boreal forests
- 2019
-
In: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 453
-
Journal article (peer-reviewed)abstract
- The current decline of terrestrial lichens in Swedish boreal forests is a major challenge for reindeer husbandry, as lichens constitute essential grazing resources for reindeer during winter. Using a 30-year data set covering northern Sweden, we explore how the successional dynamics of lichen cover depend on several forest characteristics, as well as management strategies regarding both reindeer and forestry. We found a 36% reduction of plots with lichen cover, with a decrease in lichen cover becoming more likely in recent years. Year-round presence of reindeer in forests, compared to winter grazing only, had slightly negative impacts on lichens. We found increases in lichen cover in young forests following final harvest. However, increasing basal areas as forest grow older affected lichens negatively and supported dominance of mosses. Forest management that prioritizes less dense forests with larger trees would therefore improve the ability of lichens to persist as forage resource for reindeer.
|
|
| 2. |
- Jonsson, Micael, et al.
(author)
-
Levels of forest ecosystem services depend on specific mixtures of commercial tree species.
- 2019
-
In: Nature Plants. - : Springer Science and Business Media LLC. - 2055-0278 .- 2055-026X. ; 5, s. 141-147
-
Journal article (peer-reviewed)abstract
- Global and local ecosystem change resulting in diversity loss has motivated efforts to understand relationships between species diversity and ecosystem services. However, it is unclear how such a general understanding can inform policies for the management of ecosystem services in production systems, because these systems are primarily used for food or fibre, and are rarely managed for the conservation of species diversity. Here, using data from a nationwide forest inventory covering an area of 230,000km2, we show that relative abundances of commercial tree species in mixed stands strongly influence the potential to provide ecosystem services. The mixes provided higher levels of ecosystem services compared to respective plant monocultures (overyielding or transgressive overyielding) in 35% of the investigated cases, and lower (underyielding) in 9% of the cases. We further show that relative abundances, not just species richness per se, of specific tree-species mixtures affect the potential of forests to provide multiple ecosystem services, which is crucial information for policy and sustainable forest management.
|
|
| 3. |
- Mobjörk, Malin, et al.
(author)
-
Facilitating Doctoral Education in Cross-disciplinary Milieus : Experiences from PhD-candidates
- 2019
-
Reports (other academic/artistic)abstract
- Cross-disciplinarity shapes much research today and many PhD candidates areengaged in this research. The doctoral education is a formative phase in a scientist’sintellectual development. Despite a large body of research about cross-disciplinarity,less attention has focused on how cross-disciplinarity shapes doctoral education.This report explores the organisation of doctoral education in four cross-disciplinaryresearch milieus and the experiences of 14 PhD candidates enrolled in these milieus.One key finding is that PhD candidates are more comfortable when their educationhas involved meta-communication about conceptual approaches and experiencesof conducting cross-disciplinary research. This calls for research milieus’ providingdoctoral education in cross-disciplinary settings to take a deliberative approach.This will both benefit the PhD candidates and the research milieus, and is centralin the socialisation process of the next cadre of researchers and for the future ofcross-disciplinary research.
|
|
| 4. |
- Sundqvist, Maja K., et al.
(author)
-
Experimental evidence of the long-term effects of reindeer on Arctic vegetation greenness and species richness at a larger landscape scale
- 2019
-
In: Journal of Ecology. - : Wiley-Blackwell. - 0022-0477 .- 1365-2745. ; 107:6, s. 2724-2736
-
Journal article (peer-reviewed)abstract
- Large herbivores influence plant community structure and ecosystem processes in many ecosystems. In large parts of the Arctic, reindeer (or caribou) are the only large herbivores present. Recent studies show that reindeer have the potential to mitigate recent warming‐induced shrub encroachment in the Arctic and the associated greening of high‐latitude ecosystems. This will potentially have large scale consequences for ecosystem productivity and carbon cycling.To date, information on variation in the interactions between reindeer and plants across Arctic landscapes has been scarce. We utilized a network of experimental sites across a latitudinal gradient in the Scandinavian mountains where reindeer have been excluded from 59 study plots for at least 15 years. We used this study system to test the effect of long‐term exclusion of reindeer on the abundance of major plant functional groups, the greenness indexes Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI), soil mineral nitrogen (N) and phosphorous (P), and species richness, and to determine whether the effect of reindeer exclusion is dependent on reindeer density, productivity, soil fertility or climate.We found that NDVI and LAI, lichen and deciduous shrub abundances were largely reduced while soil mineral N was enhanced by reindeer. The direction and amplitude of other plant functional group responses to reindeer exclusion differed between forest and tundra as well as shrub‐ and herbaceous‐dominated vegetation. Higher reindeer densities were related to decreased plant species richness in low‐productive sites and to increased species richness in productive sites.The relative reduction in LAI and associated absolute reductions of deciduous shrubs in response to reindeer were positively related to reindeer density, while the relative reduction in NDVI was not. Further, relative reductions in LAI and NDVI in response to reindeer were unrelated to climate and soil fertility.Synthesis. Our results provide long‐term experimental evidence highlighting the role of reindeer density in regulating plant species richness, global climate change induced greenness patterns and shrub encroachment at regional scales in the Arctic. These findings emphasize the need to consider reindeer in models predicting vegetation patterns and changes in high‐latitude ecosystems.
|
|
| 5. |
- Uboni, Alessia, et al.
(author)
-
Modelling occurrence and status of mat-forming lichens in boreal forests to assess the past and current quality of reindeer winter pastures
- 2019
-
In: Ecological Indicators. - : Elsevier. - 1470-160X .- 1872-7034. ; 96, s. 99-106
-
Journal article (peer-reviewed)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.
|
|
