Browsing by Subject "POLLEN"

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  • DiLeo, Michelle F.; Rico, Yessica; Boehmer, Hans Juergen; Wagner, Helene H. (2017)
    Ecological connectivity networks have been proposed as an efficient way to reconnect communities in fragmented landscapes. Yet few studies have evaluated if they are successful at enhancing actual functional connectivity (i.e. realized dispersal or gene flow) of focal species, or if this enhanced connectivity is enough to maintain genetic diversity and fitness of plant populations. Here we test the efficacy of an ecological connectivity network implemented in southern Germany since 1989 to reconnect calcareous grassland fragments through rotational shepherding. We genotyped 1449 individuals from 57 populations and measured fitness-related traits in 10 populations of Puisatilla vulgaris, a flagship species of calcareous grasslands in Europe. We tested if the shepherding network explained functional connectivity in P. vulgaris and if higher connectivity translated to higher genetic diversity and fitness of populations. We found that population-specific F-st was lowest in populations that had high connectivity within the shepherding network, and that well-connected populations within the network had significantly higher genetic diversity than ungrazed and more isolated grazed populations. Moreover, genetic diversity was significantly positively correlated with both seed set and seed mass. Together our results suggest that the implementation of an ecological shepherding network is an effective management measure to maintain functional connectivity and genetic diversity at the landscape scale for a calcareous grassland specialist. Populations with reduced genetic diversity would likely benefit from inclusion, or better integration into the ecological connectivity network. Our study demonstrates the often postulated but rarely tested sequence of positive associations between connectivity, genetic diversity, and fitness at the landscape scale, and provides a framework for testing the efficacy of ecological connectivity networks for focal species using molecular genetic tools.
  • Shala, Shyhrete; Helmens, Karin F.; Luoto, Tomi P.; Salonen, J. Sakari; Väliranta, Minna; Weckström, Jan (2017)
    Four biotic proxies (plant macrofossils, pollen, chironomids and diatoms) are employed to quantitatively reconstruct variations in mean July air temperatures (T-jul) at Lake Loitsana (northern Finland) during the Holocene. The aim is to evaluate the robustness and biases in these temperature reconstructions and to compare the timing of highest T-jul in the individual reconstructions. The reconstructed T-jul values are evaluated in relation to local-scale/site-specific processes associated with the Holocene lake development at Loitsana as these factors have been shown to significantly influence the fossil assemblages found in the Lake Loitsana sediments. While pollen-based temperatures follow the classical trend of gradually increasing early-Holocene T-jul with a mid-Holocene maximum, the aquatic/wetland assemblages reconstruct higher-than-present T-jul already during the early Holocene, that is, at the peak of summer insolation. The relatively low early-Holocene July temperatures recorded by the pollen are the result of site-specific factors possibly combined with a delayed response of the terrestrial ecosystem compared with the aquatic ecosystem. Our study shows that all reconstructions are influenced at least to some extent by local factors. This finding stresses the need to evaluate quantitatively reconstructed climate values against local lake development and highlights the benefit of using multi-proxy data in Holocene climate reconstructions.
  • Elshibli, Sakina; Korpelainen, Helena (2021)
    Medemia argun is a wild, dioecious palm, adapted to the harsh arid environment of the Nubian Desert in Sudan and southern Egypt. There is a concern about its conservation status, since little is known about its distribution, abundance, and genetic variation. M. argun grows on the floodplains of seasonal rivers (wadis). The continuing loss of suitable habitats in the Nubian Desert is threatening the survival of this species. We analyzed the genetic diversity, population genetic structure, and occurrence of M. argun populations to foster the development of conservation strategies for M. argun. Genotyping-by-sequencing (GBS) analyses were performed using a whole-genome profiling service. We found an overall low genetic diversity and moderate genetic structuring based on 40 single-nucleotide polymorphisms (SNPs) and 9,866 SilicoDArT markers. The expected heterozygosity of the total population (H-T) equaled 0.036 and 0.127, and genetic differentiation among populations/groups (F-ST) was 0.052 and 0.092, based on SNP and SilicoDArT markers, respectively. Bayesian clustering analyses defined five genetic clusters that did not display any ancestral gene flow among each other. Based on SilicoDArT markers, the results of the analysis of molecular variance (AMOVA) confirmed the previously observed genetic differentiation among generation groups (23%; p < 0.01). Pairwise F-ST values indicated a genetic gap between old and young individuals. The observed low genetic diversity and its loss among generation groups, even under the detected high gene flow, show genetically vulnerable M. argun populations in the Nubian Desert in Sudan. To enrich and maintain genetic variability in these populations, conservation plans are required, including collection of seed material from genetically diverse populations and development of ex situ gene banks.
  • Alenius, Teija Helena; Gerasimov, Dmitry; Sapelko, Tatiana V; Ludikova, Anna; Kuznetsov, Denis; Golyeva, A; Nordqvist, Kerkko (2020)
    This paper presents the results of pollen, diatom, charcoal, and sediment analyses from Lake Bol'shoye Zavetnoye, situated between the Gulf of Finland and Lake Ladoga on the Karelian Isthmus, north-western Russia. The main goal is to contribute to the discussion of Neolithic land use in north-eastern Europe. The article aims to answer questions related to Stone Age hunter-gatherer economy, ecology, and anthropogenic environmental impact through a comprehensive combination of multiple types of palaeoecological data and archaeological material. According to diatom data, Lake Bol'shoye Zavetnoye was influenced by the water level oscillations of Ancient Lake Ladoga during much of the Holocene. Intensified human activity and prolonged human occupation become visible in the Lake Bol'shoye Zavetnoye pollen data between 4480 BC and 3250 BC. During the final centuries of the Stone Age, a new phase of land use began, as several anthropogenic indicators, such asTriticum, Cannabis, andPlantago lanceolataappear in the pollen data and a decrease inPinusvalues is recorded. In general, the results indicate that socio-cultural transformations could have taken place already from the mid-5th millennium BC onwards, including new ways of utilizing the environment, perhaps also in the field of subsistence, even though the livelihood was based on foraging throughout the period.
  • Seddon, Alistair W. R.; Mackay, Anson W.; Baker, Ambroise G.; Birks, H. John B.; Breman, Elinor; Buck, Caitlin E.; Ellis, Erle C.; Froyd, Cynthia A.; Gill, Jacquelyn L.; Gillson, Lindsey; Johnson, Edward A.; Jones, Vivienne J.; Juggins, Stephen; Macias-Fauria, Marc; Mills, Keely; Morris, Jesse L.; Nogues-Bravo, David; Punyasena, Surangi W.; Roland, Thomas P.; Tanentzap, Andrew J.; Willis, Kathy J.; Aberhan, Martin; van Asperen, Eline N.; Austin, William E. N.; Battarbee, Rick W.; Bhagwat, Shonil; Belanger, Christina L.; Bennett, Keith D.; Birks, Hilary H.; Ramsey, Christopher Bronk; Brooks, Stephen J.; de Bruyn, Mark; Butler, Paul G.; Chambers, Frank M.; Clarke, Stewart J.; Davies, Althea L.; Dearing, John A.; Ezard, Thomas H. G.; Feurdean, Angelica; Flower, Roger J.; Gell, Peter; Hausmann, Sonja; Hogan, Erika J.; Hopkins, Melanie J.; Jeffers, Elizabeth S.; Korhola, Atte A.; Marchant, Robert; Kiefer, Thorsten; Lamentowicz, Mariusz; Larocque-Tobler, Isabelle; Lopez-Merino, Lourdes; Liow, Lee H.; McGowan, Suzanne; Miller, Joshua H.; Montoya, Encarni; Morton, Oliver; Nogue, Sandra; Onoufriou, Chloe; Boush, Lisa P.; Rodriguez-Sanchez, Francisco; Rose, Neil L.; Sayer, Carl D.; Shaw, Helen E.; Payne, Richard; Simpson, Gavin; Sohar, Kadri; Whitehouse, Nicki J.; Williams, John W.; Witkowski, Andrzej (2014)
    1. Priority question exercises are becoming an increasingly common tool to frame future agendas in conservation and ecological science, used to identify research foci which are relevant to the needs of the scientific community and which also have high policy and conservation relevance. 2. To date there has been no coherent synthesis of key questions and priority research areas for palaeoecology, which combines biological, geochemical and molecular techniques in order to reconstruct ecological and environmental systems far into the past. 3. We adapted a well-established methodology to identify 50 priority research questions in palaeoecology. We used a set of criteria that were designed to identify realistic and achievable research goals, and selected questions from a pool submitted by the international palaeoecology research community and relevant policy practitioners. Questions are not ranked by priority but are grouped thematically, and are generally focussed on the late Cenozoic onwards (past c. 65 Ma). 4. The major difference in our methodology compared to other, similar exercises was the integration of online participation both before and during the workshop, representing an important development for increasing engagement and visibility. 5. The questions selected are structured around six themes: human-environment interactions in the Anthropocene; biodiversity, conservation, and novel ecosystems; biodiversity over long timescales; ecosystem processes and biogeochemical cycling; comparing, combining and synthesising information from multiple records; and methodological approaches to palaeoecology. 6. Future opportunities in palaeoecology are related to improved incorporation of uncertainty into reconstructions, an enhanced understanding of ecological and evolutionary dynamics and processes, and the continued application of long-term data for better-informed landscape management. 7. SYNTHESIS: The 50 priority questions selected in this exercise present palaeoecological science as a vibrant and thriving discipline, and highlight its vast potential for resolving both pure (e.g. theoretical) and applied (e.g. environmental) research questions directly related to ecological science and global change.
  • Kylander, Malin E.; Plikk, Anna; Rydberg, Johan; Löwemark, Ludvig; Salonen, J. Sakari; Fernandez-Fernandez, Maria; Helmens, Karin (2018)
    Biological proxies from the Sokli Eemian (Marine Isotope Stage 5e) paleolake sequence from northeast Finland have previously shown that, unlike many postglacial records from boreal sites, the lake becomes increasingly eutrophic over time. Here, principal components (PC) were extracted from a high resolution multi-element XRF core scanning dataset to describe minerogenic input from the wider catchment (PC1), the input of S, Fe, Mn, and Ca-rich detrital material from the surrounding Sokli Carbonatite Massif (PC2), and chemical weathering (PC3). Minerogenic inputs to the lake were elevated early in the record and during two abrupt cooling events when soils and vegetation in the catchment were poor. Chemical weathering in the catchment generally increased over time, coinciding with higher air temperatures, catchment productivity, and the presence of acidic conifer species. Abiotic edaphic processes play a key role in lake ontogeny at this site stemming from the base cation- and nutrient-rich bedrock, which supports lake alkalinity and productivity. The climate history at this site, and its integrated effects on the lake system, appear to override development processes and alters its long-term trajectory.
  • Siljamo, Pilvi; Sofiev, Mikhail; Ranta, Hanna; Linkosalo, Tapio; Kubin, Eero; Ahas, Rein; Genikhovich, Eugene; Jatczak, Katarzyna; Jato, Victoria; Nekovar, Jiri; Minin, Alexander; Severova, Elena; Shalaboda, Valentina (2008)
  • Kuosmanen, Niina; Marquer, Laurent; Tallavaara, Miikka; Molinari, Chiara; Zhang, Yurui; Alenius, Teija; Edinborough, Kevan; Pesonen, Petro; Reitalu, Triin; Renssen, Hans; Trondman, Anna-Kari; Seppa, Heikki (2018)
    QuestionsWe investigated the changing role of climate, forest fires and human population size in the broad-scale compositional changes in Holocene vegetation dynamics before and after the onset of farming in Sweden (at 6,000cal yr BP) and in Finland (at 4,000calyr BP). LocationSouthern and central Sweden, SW and SE Finland. MethodsHolocene regional plant abundances were reconstructed using the REVEALS model on selected fossil pollen records from lakes. The relative importance of climate, fires and human population size on changes in vegetation composition was assessed using variation partitioning. Past climate variable was derived from the LOVECLIM climate model. Fire variable was reconstructed from sedimentary charcoal records. Estimated trend in human population size was based on the temporal distribution of archaeological radiocarbon dates. ResultsClimate explains the highest proportion of variation in vegetation composition during the whole study period in Sweden (10,000-4,000cal yr BP) and in Finland (10,000-1,000cal yr BP), and during the pre-agricultural period. In general, fires explain a relatively low proportion of variation. Human population size has significant effect on vegetation dynamics after the onset of farming and explains the highest variation in vegetation in S Sweden and SW Finland. ConclusionsMesolithic hunter-gatherer populations did not significantly affect vegetation composition in Fennoscandia, and climate was the main driver of changes at that time. Agricultural communities, however, had greater effect on vegetation dynamics, and the role of human population size became a more important factor during the late Holocene. Our results demonstrate that climate can be considered the main driver of long-term vegetation dynamics in Fennoscandia. However, in some regions the influence of human population size on Holocene vegetation changes exceeded that of climate and has a longevity dating to the early Neolithic.