| 1. |
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| 2. |
- Pamilo, P, et al.
(author)
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Molecular population genetics of social insects
- 1997
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In: ANNUAL REVIEW OF ECOLOGY AND SYSTEMATICS. - : ANNUAL REVIEWS INC. ; 28, s. 1-25
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Review (other academic/artistic)abstract
- The life of social insects centers around sedentary colonies that can include individuals belonging to different patrilines or matrilines, with a turnover of reproductives. The colony is a scene for both cooperation and conflicts, and the conceptual frame
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| 3. |
- Sundqvist, Hanna S., et al.
(author)
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Arctic Holocene proxy climate database - new approaches to assessing geochronological accuracy and encoding climate variables
- 2014
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In: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 10:4, s. 1605-1631
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Journal article (peer-reviewed)abstract
- We present a systematic compilation of previously published Holocene proxy climate records from the Arctic. We identified 170 sites from north of 58 degrees N latitude where proxy time series extend back at least to 6 cal ka (all ages in this article are in calendar years before present - BP), are resolved at submillennial scale (at least one value every 400 +/- 200 years) and have age models constrained by at least one age every 3000 years. In addition to conventional meta-data for each proxy record (location, proxy type, reference), we include two novel parameters that add functionality to the database. First, climate interpretation is a series of fields that logically describe the specific climate variable(s) represented by the proxy record. It encodes the proxy-climate relation reported by authors of the original studies into a structured format to facilitate comparison with climate model outputs. Second, geochronology accuracy score (chron score) is a numerical rating that reflects the overall accuracy of C-14-based age models from lake and marine sediments. Chron scores were calculated using the original author-reported C-14 ages, which are included in this database. The database contains 320 records (some sites include multiple records) from six regions covering the circumpolar Arctic: Fennoscandia is the most densely sampled region (31% of the records), whereas only five records from the Russian Arctic met the criteria for inclusion. The database contains proxy records from lake sediment (60 %), marine sediment (32 %), glacier ice (5 %), and other sources. Most (61 %) reflect temperature (mainly summer warmth) and are primarily based on pollen, chironomid, or diatom assemblages. Many (15 %) reflect some aspect of hydroclimate as inferred from changes in stable isotopes, pollen and diatom assemblages, humification index in peat, and changes in equilibrium-line altitude of glaciers. This comprehensive database can be used in future studies to investigate the spatio-temporal pattern of Arctic Holocene climate changes and their causes. The Arctic Holocene data set is available from NOAA Paleoclimatology.
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| 4. |
- Trondman, Anna-Kari, et al.
(author)
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Pollen-based quantitative reconstructions of Holocene regional vegetation cover (plant-functional types and land-cover types) in Europe suitable for climate modelling
- 2015
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In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 21:2, s. 676-697
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Journal article (peer-reviewed)abstract
- We present quantitative reconstructions of regional vegetation cover in north-western Europe, western Europe north of the Alps, and eastern Europe for five time windows in the Holocene [around 6k, 3k, 0.5k, 0.2k, and 0.05k calendar years before present (bp)] at a 1 degrees x1 degrees spatial scale with the objective of producing vegetation descriptions suitable for climate modelling. The REVEALS model was applied on 636 pollen records from lakes and bogs to reconstruct the past cover of 25 plant taxa grouped into 10 plant-functional types and three land-cover types [evergreen trees, summer-green (deciduous) trees, and open land]. The model corrects for some of the biases in pollen percentages by using pollen productivity estimates and fall speeds of pollen, and by applying simple but robust models of pollen dispersal and deposition. The emerging patterns of tree migration and deforestation between 6k bp and modern time in the REVEALS estimates agree with our general understanding of the vegetation history of Europe based on pollen percentages. However, the degree of anthropogenic deforestation (i.e. cover of cultivated and grazing land) at 3k, 0.5k, and 0.2k bp is significantly higher than deduced from pollen percentages. This is also the case at 6k in some parts of Europe, in particular Britain and Ireland. Furthermore, the relationship between summer-green and evergreen trees, and between individual tree taxa, differs significantly when expressed as pollen percentages or as REVEALS estimates of tree cover. For instance, when Pinus is dominant over Picea as pollen percentages, Picea is dominant over Pinus as REVEALS estimates. These differences play a major role in the reconstruction of European landscapes and for the study of land cover-climate interactions, biodiversity and human resources.
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| 6. |
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| 7. |
- Fernandez-Escudero, I, et al.
(author)
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Dependent colony founding in the ant Proformica longiseta
- 2001
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In: INSECTES SOCIAUX. - : BIRKHAUSER VERLAG AG. - 0020-1812. ; 48:1, s. 80-82
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Journal article (peer-reviewed)abstract
- In polygynous ants, queens often found new nests dependently by budding, where one or more queens leave the old nest with some workers and establish a new one. Even though budding is assumed to be relatively common in polygynous ants, it has rarely been d
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| 8. |
- Gaillard, Marie-José, 1953-, et al.
(author)
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Holocene land-cover reconstructions for studies on land cover-climate feedbacks
- 2010
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In: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 6, s. 483-499
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Journal article (peer-reviewed)abstract
- The major objectives of this paper are: (1) to review the pros and cons of the scenarios of past anthropogenic land cover change (ALCC) developed during the last ten years, (2) to discuss issues related to pollen-based reconstruction of the past land-cover and introduce a new method, REVEALS (Regional Estimates of VEgetation Abundance from Large Sites), to infer long-term records of past land-cover from pollen data, (3) to present a new project (LANDCLIM: LAND cover – CLIMate interactions in NW Europe during the Holocene) currently underway, and show preliminary results of REVEALS reconstructions of the regional land-cover in the Czech Republic for five selected time windows of the Holocene, and (4) to discuss the implications and future directions in climate and vegetation/land-cover modeling, and in the assessment of the effects of human-induced changes in land-cover on the regional climate through altered feedbacks. The existing ALCC scenarios show large discrepancies between them, and few cover time periods older than AD 800. When these scenarios are used to assess the impact of human land-use on climate, contrasting results are obtained. It emphasizes the need for methods such as the REVEALS model-based land-cover reconstructions. They might help to fine-tune descriptions of past land-cover and lead to a better understanding of how long-term changes in ALCC might have influenced climate. The REVEALS model is demonstrated to provide better estimates of the regional vegetation/landcover changes than the traditional use of pollen percentages. This will achieve a robust assessment of land cover at regional- to continental-spatial scale throughout the Holocene. We present maps of REVEALS estimates for the percentage cover of 10 plant functional types (PFTs) at 200 BP and 6000 BP, and of the two open-land PFTs “grassland” and “agricultural land” at five time-windows from 6000 BP to recent time. The LANDCLIM results are expected to provide crucial data to reassess ALCC estimates for a better understanding of the land suface-atmosphere interactions.
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| 9. |
- SEPPA, P, et al.
(author)
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GENE FLOW AND POPULATION VISCOSITY IN MYRMICA ANTS
- 1995
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In: HEREDITY. - : BLACKWELL SCIENCE LTD. - 0018-067X. ; 74, s. 200-209
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Journal article (other academic/artistic)abstract
- The amount of gene flow and population viscosity were studied in two red ant species, Myrmica ruginodis and M. rubra. Differentiation between populations at the local scale (within the dispersal distance of individuals) and between localities further apar
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| 10. |
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| 11. |
- Seppa, P., et al.
(author)
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Mosaic structure of native ant supercolonies
- 2012
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In: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 21:23, s. 5880-5891
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Journal article (peer-reviewed)abstract
- According to the inclusive fitness theory, some degree of positive relatedness is required for the evolution and maintenance of altruism. However, ant colonies are sometimes large interconnected networks of nests, which are genetically homogenous entities, causing a putative problem for the theory. We studied spatial structure and genetic relatedness in two supercolonies of the ant Formica exsecta, using nuclear and mitochondrial markers. We show that there may be multiple pathways to supercolonial social organization leading to different spatial genetic structures. One supercolony formed a genetically homogenous population dominated by a single mtDNA haplotype, as expected if founded by a small number of colonizers, followed by nest propagation by budding and domination of the habitat patch. The other supercolony had several haplotypes, and the spatial genetic structure was a mosaic of nuclear and mitochondrial clusters. Genetic diversity probably originated from long-range dispersal, and the mosaic population structure is likely a result of stochastic short-range dispersal of individuals. Such a mosaic spatial structure is apparently discordant with the current knowledge about the integrity of ant colonies. Relatedness was low in both populations when estimated among nestmates, but increased significantly when estimated among individuals sharing the same genetic cluster or haplogroup. The latter association indicates the important historical role of queen dispersal in the determination of the spatial genetic structure.
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| 12. |
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| 13. |
- Boy, M., et al.
(author)
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Interactions between the atmosphere, cryosphere, and ecosystems at northern high latitudes
- 2019
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In: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 19:3, s. 2015-2061
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Journal article (peer-reviewed)abstract
- The Nordic Centre of Excellence CRAICC (Cryosphere-Atmosphere Interactions in a Changing Arctic Climate), funded by NordForsk in the years 2011-2016, is the largest joint Nordic research and innovation initiative to date, aiming to strengthen research and innovation regarding climate change issues in the Nordic region. CRAICC gathered more than 100 scientists from all Nordic countries in a virtual centre with the objectives of identifying and quantifying the major processes controlling Arctic warming and related feedback mechanisms, outlining strategies to mitigate Arctic warming, and developing Nordic Earth system modelling with a focus on short-lived climate forcers (SLCFs), including natural and anthropogenic aerosols. The outcome of CRAICC is reflected in more than 150 peer-reviewed scientific publications, most of which are in the CRAICC special issue of the journal Atmospheric Chemistry and Physics. This paper presents an overview of the main scientific topics investigated in the centre and provides the reader with a state-of-the-art comprehensive summary of what has been achieved in CRAICC with links to the particular publications for further detail. Faced with a vast amount of scientific discovery, we do not claim to completely summarize the results from CRAICC within this paper, but rather concentrate here on the main results which are related to feedback loops in climate change-cryosphere interactions that affect Arctic amplification.
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| 14. |
- Fang, Keyan, et al.
(author)
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Climate of the late Pleistocene and early Holocene in coastal South China inferred from submerged wood samples
- 2017
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In: Quaternary International. - : Elsevier BV. - 1040-6182. ; 447, s. 111-117
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Journal article (peer-reviewed)abstract
- Tree-ring variability of submerged wood specimens in coastal areas provides important clues about sea level change and climate variability of the past. We dated submerged wood samples from coastal Fujian province in China using the radiocarbon methods and investigated their tree-ring variability. The submerged wood samples from the Shenhu Bay that date to the early Holocene (similar to 8000 calibrated years B.P.) may be related to the rise of the sea level after the Last Glacial Maximum (LGM). The submerged wood samples from the Qianhu Bay site dated to the Marine Isotope Stage 3 (MIS 3) (> 40,000 calibrated years B. P.). Most of the submerged wood samples are from coniferous trees with frequent branching tree rings. Frequent branching tree rings in this region are mostly found from the currently endangered coniferous species with narrow ecological amplitude at humid sites. Tree rings of the submerged sample show conspicuous interdecadal variability (similar to 20 years) than interannual variations, which differs from modern tree rings of nearby regions which have stronger interannual and multi-decadal variability. Our study highlights the potential to use submerged samples of coastal Southeast China for paleoclimate studies.
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| 15. |
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| 16. |
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| 17. |
- Seppa, P, et al.
(author)
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Genetic structure of island populations of the anurans Rana temporaria and Bufo bufo
- 1999
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In: HEREDITY. - : BLACKWELL SCIENCE LTD. - 0018-067X. ; 82, s. 309-317
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Journal article (other academic/artistic)abstract
- Amphibians have traditionally been considered to have low dispersal ability and they have become a model for studies on the effects of man-made habitat fragmentation on genetic variation and population differentiation. This study examined the genetic popu
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| 18. |
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| 19. |
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| 20. |
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| 21. |
- Strandberg, Gustav, et al.
(author)
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Regional climate model simulations for Europe at 6 and 0.2 k BP : sensitivity to changes in anthropogenic deforestation
- 2014
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In: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 10:2, s. 661-680
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Journal article (peer-reviewed)abstract
- This study aims to evaluate the direct effects of anthropogenic deforestation on simulated climate at two contrasting periods in the Holocene, similar to 6 and similar to 0.2 k BP in Europe. We apply We apply the Rossby Centre regional climate model RCA3, a regional climate model with 50 km spatial resolution, for both time periods, considering three alternative descriptions of the past vegetation: (i) potential natural vegetation (V) simulated by the dynamic vegetation model LPJ-GUESS, (ii) potential vegetation with anthropogenic land use (deforestation) from the HYDE3.1 (History Database of the Global Environment) scenario (V + H3.1), and (iii) potential vegetation with anthropogenic land use from the KK10 scenario (V + KK10). The climate model results show that the simulated effects of deforestation depend on both local/regional climate and vegetation characteristics. At similar to 6 k BP the extent of simulated deforestation in Europe is generally small, but there are areas where deforestation is large enough to produce significant differences in summer temperatures of 0.5-1 degrees C. At similar to 0.2 k BP, extensive deforestation, particularly according to the KK10 model, leads to significant temperature differences in large parts of Europe in both winter and summer. In winter, deforestation leads to lower temperatures because of the differences in albedo between forested and unforested areas, particularly in the snow-covered regions. In summer, deforestation leads to higher temperatures in central and eastern Europe because evapotranspiration from unforested areas is lower than from forests. Summer evaporation is already limited in the southernmost parts of Europe under potential vegetation conditions and, therefore, cannot become much lower. Accordingly, the albedo effect dominates in southern Europe also in summer, which implies that deforestation causes a decrease in temperatures. Differences in summer temperature due to deforestation range from -1 degrees C in south-western Europe to +1 degrees C in eastern Europe. The choice of anthropogenic land-cover scenario has a significant influence on the simulated climate, but uncertainties in palaeoclimate proxy data for the two time periods do not allow for a definitive discrimination among climate model results.
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| 22. |
- Walin, L, et al.
(author)
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Resource allocation in the red ant Myrmica ruginodis - an interplay of genetics and ecology
- 2001
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In: JOURNAL OF EVOLUTIONARY BIOLOGY. - : BLACKWELL SCIENCE LTD. - 1010-061X. ; 14:5, s. 694-707
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Journal article (peer-reviewed)abstract
- Worker-queen conflicts over reproductive allocation (colony maintenance vs. reproduction) and sex allocation (females vs. males) were examined in two populations of the facultatively polygynous ant Myrmica ruginodis. Plasticity of social organization in t
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