Browsing by Subject "ENVIRONMENTAL-CHANGE"

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  • Charman, D. J.; Beilman, D. W.; Blaauw, M.; Booth, R. K.; Brewer, S.; Chambers, F. M.; Christen, J. A.; Gallego-Sala, A.; Harrison, S. P.; Hughes, P. D. M.; Jackson, S. T.; Korhola, A.; Mauquoy, D.; Mitchell, F. J. G.; Prentice, I. C.; van der Linden, M.; De Vleeschouwer, F.; Yu, Z. C.; Alm, J.; Bauer, I. E.; Corish, Y. M. C.; Garneau, M.; Hohl, V.; Huang, Y.; Karofeld, E.; Le Roux, G.; Loisel, J.; Moschen, R.; Nichols, J. E.; Nieminen, T. M.; MacDonald, G. M.; Phadtare, N. R.; Rausch, N.; Sillasoo, Ue; Swindles, G. T.; Tuittila, E-S.; Ukonmaanaho, L.; Valiranta, M.; van Bellen, S.; van Geel, B.; Vitt, D. H.; Zhao, Y. (2013)
  • Luoto, Tomi P.; Ojala, Antti E.K. (2018)
    Arctic freshwater basins are diversity hotspots and sentinels of climate change, but their long-term variability and the environmental variables controlling them are not well defined. We examined four available lake sediment sequences from High Arctic Svalbard for their subfossil Chironomidae communities, biodiversity and functional traits and assessed the influence of climatic and limnological variability on the long-term ecological dynamics. Our results indicated that collector-filterers had an important role in the oligotrophic sites, whereas collector-gatherers dominated the nutrient-enriched sites with significant bird guano inputs. In the oligotrophic sites, benthic production, taxon richness and taxonomic and functional diversity were highest during the early Holocene, when temperatures showed a rapid increase. An increase in subfossil abundance and diversity metrics was also found in recent samples of the oligotrophic sites, but not in the bird-impacted sites, where the trends were decreasing. When partitioning out the environmental forcing on chironomid communities, the influence of climate was significant in all the sites, whereas in-lake production (organic matter) was significant in two of the sites and catchment erosion (magnetic susceptibility) had only minor influence. The findings suggest that major changes in Arctic chironomid assemblages were driven by climate warming with increasing diversity in oligotrophic sites, but deteriorating ecological functions in environmentally stressed sites. We found that although taxonomic and functional diversity were always coupled, taxonomical and functional turnovers were coupled only in the oligotrophic sites suggesting that the ecological functions operated by chironomids in these low-productivity sites may not be as resilient to future environmental change.
  • Huang, Yongjiang; Jacques, Frederic M. B.; Su, Tao; Ferguson, David K.; Tang, Hui; Chen, Wenyun; Zhou, Zhekun (2015)
    Cenozoic plant relicts are those groups that were once widespread in the Northern Hemisphere but are now restricted to some small isolated areas as a result of drastic climatic changes. They are good proxies to study how plants respond to climatic changes since their modern climatic requirements are known. Herein we look at the modern distribution of 65 palaeoendemic genera in China and compare it with the Chinese climatic pattern, in order to find a link between the plant distribution and climate. Central China and Taiwan Island are shown to be diversity centres of Cenozoic relict genera, consistent with the fact that these two regions have a shorter dry season with comparatively humid autumn and spring in China. Species distribution models indicate that the precipitation parameters are the most important variables to explain the distribution of relict genera. The Cenozoic wide-scale distribution of relict plants in the Northern Hemisphere is therefore considered to be linked to the widespread humid climate at that time, and the subsequent contraction of their distributional ranges was probably caused by the drying trend along with global cooling.
  • Milicic, Marija; Vujic, Ante; Cardoso, Pedro (2018)
    Climate change presents a serious threat to global biodiversity. Loss of pollinators in particular has major implications, with extirpation of these species potentially leading to severe losses in agriculture and, thus, economic losses. In this study, we forecast the effects of climate change on the distribution of hoverflies in Southeast Europe using species distribution modelling and climate change scenarios for two time-periods. For 2041-2060, 19 analysed species were predicted to increase their areas of occupancy, with the other 25 losing some of their ranges. For 2061-2080, 55% of species were predicted to increase their area of occupancy, while 45% were predicted to experience range decline. In general, range size changes for most species were below 20%, indicating a relatively high resilience of hoverflies to climate change when only environmental variables are considered. Additionally, range-restricted species are not predicted to lose more area proportionally to widespread species. Based on our results, two distributional trends can be established: the predicted gain of species in alpine regions, and future loss of species from lowland areas. Considering that the loss of pollinators from present lowland agricultural areas is predicted and that habitat degradation presents a threat to possible range expansion of hoverflies in the future, developing conservation management strategy for the preservation of these species is crucial. This study represents an important step towards the assessment of the effects of climate changes on hoverflies and can be a valuable asset in creating future conservation plan, thus helping in mitigating potential consequences.
  • Schenk, Frederik; Bennike, Ole; Valiranta, Minna; Avery, Rachael; Björck, Svante; Wohlfarth, Barbara (2020)
    The global climate transition from the Lateglacial to the Early Holocene is dominated by a rapid warming trend driven by an increase in orbital summer insolation over high northern latitudes and related feedbacks. The warming trend was interrupted by several abrupt shifts between colder (stadial) and warmer (interstadial) climate states following instabilities of the Atlantic Meridional Overturning Circulation (AMOC) in response to rapidly melting ice sheets. The sequence of abrupt shifts between extreme climate states had profound impacts on ecosystems which make it challenging to reliably quantify state variables like July temperatures within a non-analogue climate envelope. For Europe, there is increasing albeit inconclusive evidence for higher stadial summer temperatures than initially thought. Here we present a comprehensive floral compilation of plant macrofossils from lake sediment cores of 15 sites from S-Scandinavia covering the period similar to 15 to 11 ka BP. We find evidence for a continued presence of plant species indicating high July temperatures throughout the last deglaciation. The presence of hemiboreal plants in close vicinity to the southern margin of the Fennoscandian Ice Sheet implies a strong thermal summer forcing for the rapid ice sheet melt. Consistent with some recent studies, we do not find evidence for a general stadial summer cooling, which indicates that other reasons than summer temperatures caused drastic setbacks in proxy signals possibly driven by extreme winter cooling and/or shorter warm seasons. (C) 2020 The Authors. Published by Elsevier Ltd.
  • Lo, Veronica B. P. G.; Lopez-Rodriguez, Maria D.; Metzger, Marc J.; Oteros-Rozas, Elisa; Cebrian-Piqueras, Miguel A.; Ruiz-Mallen, Isabel; March, Hug; Raymond, Christopher M. (2022)
    Envisioning processes enable protected area managers to chart a course for future management to reach desired goals, but unexpected changes that could affect future visions are not usually considered. The global COVID-19 pandemic provided an opportunity to explore changes in stakeholder visions, the values that underpin the visions, and their perceptions of landscape changes and the underlying drivers (e.g. climate change, mass tourism and demographic trends). Through a mixed-methods approach in this post-evaluation study, we gathered comparative data on these issues from stakeholders in the Sierra de Guadarrama National Park, Spain, between July 2019 (pre-pandemic) and October 2020 (mid-pandemic). Our qualitative analysis demonstrates that pre-pandemic, differences in visions for protected area management were largely spurred by different perceptions of drivers of change, rather than differences in values or perceived landscape changes, which were similar across different vision themes. One year later, in the midst of the COVID-19 pandemic, the majority of stakeholders reported that their values, visions and perceptions of drivers did not change despite this large-scale disturbance. Of the 20%-30% of stakeholders that did report changes, visions generally shifted towards greater prioritization of biodiversity and nature conservation as a result of heightened perceptions of the impacts of drivers of change associated with an increase in the numbers of park visitors. These drivers included mass tourism, mountain recreation, lack of environmental awareness, and change in values and traditions. Our findings reinforce the importance of adaptive and inclusive management of protected areas, including enhancing transparency and communications regarding factors driving change in the landscape, and integration of local and traditional knowledge and stakeholder perceptions of changes and drivers. Furthermore, management plans integrating stakeholder values have the potential to stay relevant even in the face of wildcard events such as a pandemic. To enhance the relevancy of visions and scenarios in conservation and land-use planning, scenario planning methodologies should more strongly consider different potential disturbances and how drivers of change in the near and far future can be affected by wildcard events such as a pandemic. A free Plain Language Summary can be found within the Supporting Information of this article.
  • Gravolin, Isaac; Lehtonen, Topi Kasperi; Deal, Nicholas D. S.; Candolin, Ulrika; Wong, Bob (2021)
    Nest predation has a large impact on reproductive success in many taxa. Defending offspring from would-be predators can also be energetically and physiologically costly for parents. Thus, to maximize their reproductive payoffs, individuals should adjust their reproductive behaviors in relation to the presence of nest predators. However, effects of nest predator presence on parental behaviors across multiple reproductive contexts remain poorly understood, particularly in non-avian taxa. We ran a series of experiments to test how the presence of an egg predator, the invasive rockpool shrimp, Palaemon elegans, influences male reproductive decisions and egg survival in a species of fish with exclusive paternal care, the three-spined stickleback, Gasterosteus aculeatus. We found that, in the presence of shrimp, male sticklebacks were less likely to build a nest, invested less in territory defense against an intruder, and tended to fan eggs in their nest less and in shorter bouts, but did not alter their investment in courtship behavior. The predator's presence also did not affect egg survival rates, suggesting that males effectively defended their brood from the shrimp. These results show that reproducing individuals can be highly responsive to the presence of nest predators and adjust their behavioral decisions accordingly across a suite of reproductive contexts.
  • Heikkilä, Maija; Ribeiro, Sofia; Weckström, Kaarina; Pienkowski, Anna J. (2022)
    Frozen components on land and in the ocean (sea ice, ice sheets, glaciers and permafrost) form the cryosphere, which, together with the ocean, moderates the physical and chemical habitat for life in the Arctic and beyond. Changes in these components, as a response to rapidly warming climate in the Arctic, are intensely expressed in the coastal zone. These areas receive increased terrestrial runoff while subject to a changing sea-ice and ocean environment. Proxies derived from marine sediment archives provide long-term data that extend beyond instrumental measurements. They are therefore fundamental in disentangling human-driven versus natural processes, changes and responses. This paper (1) provides an overview of current Arctic cryosphere change, (2) reviews state-of-the-art palaeoecological approaches, (3) identifies methodological and knowledge gaps, and (4) discusses the strengths and future potential of palaeoecology and palaeoceanography to respond to societally relevant coastal marine ecosystem challenges. We utilise responses to an open survey conducted by the Future Earth Past Global Changes (PAGES) working group Arctic Cryosphere Change and Coastal Marine Ecosystems (ACME). Significant research advancements have taken place in recent decades, including the increasingly common use of multi-proxy (multiple lines of evidence) studies, improved understanding of species-environment relationships, and development of novel proxies. Significant gaps remain, however, in the understanding of proxy sources and behaviour, the use of quantitative techniques, and the availability of reference data from coastal environments. We highlight the need for critical methodological refinement, interdisciplinary collaboration on research approaches, and enhanced communication across the scientific community.
  • Helmens, Karin F.; Katrantsiotis, Christos; Kuosmanen, Niina; Luoto, Tomi P.; Salonen, J. Sakari; Valiranta, Minna (2021)
    Few fossil-based environmental and climate records in northern Europe are dated to Marine Isotope Stage (MIS) 5a around 80 ka BP. We here present multiple environmental and climate proxies obtained from a lake sequence of MIS 5a age in the Sokli basin (northern Finland). Pollen/spores, plant macrofossils, NPPs (e.g. green algae), bryozoa, diatoms and chironomids allowed an exceptionally detailed reconstruction of aquatic and telmatic ecosystem successions related to the development of the Sokli Ice Lake and subsequent infilling of a relatively small and shallow lake confined to the Sokli basin. A regional vegetation development typical for the early half of an interglacial is recorded by the pollen, stomata and plant macrofossil data. Reconstructions of July temperatures based on pollen assemblages suffer from a large contribution of local pollen from the lake's littoral zone. Summer temperatures reaching present-day values, inferred for the upper part of the lake sequence, however, agree with the establishment of pine-dominated boreal forest indicated by the plant fossil data. Habitat preferences also influence the climate record based on chironomids. Nevertheless, the climate optima of the predominant intermediate- to warm-water chironomid taxa suggest July temperatures exceeding present-day values by up to several degrees, in line with climate inferences from a variety of aquatic and wetland plant indicator species. The disequilibrium between regional vegetation development and warm, insolation-forced summers is also reported for Early Holocene records from northern Fennoscandia. The MIS 5a sequence is the last remaining fossil-bearing deposit in the late Quaternary basin infill at Sokli to be studied using multi-proxy evidence. A unique detailed climate record for MIS 5 is now available for formerly glaciated northern Europe. Our studies indicate that interglacial conditions persisted into MIS 5a, in agreement with data for large parts of the European mainland, shortening the Last Glacial by some 50 ka to MIS 4-2.
  • Luoto, Tomi P.; Ojala, Antti E. K.; Zajaczkowski, Marek (2019)
    We used fossil Chironomidae assemblages and the transfer function approach to reconstruct summer air temperatures over the past 300 years from a High Arctic lake in Hornsund, Svalbard. Our aims were to compare reconstructed summer temperatures with observed (last 100 years) seasonal temperatures, to determine a potential climate warming break point in the temperature series and to assess the significance and rate of the climate warming trend at the study site. The reconstructed temperatures were consistent with a previous proxy record from Svalbard and showed good correlation with the meteorological observations from Bjornoya and Longyearbyen. From the current palaeoclimate record, we found a significant climate warming threshold in the 1930s, after which the temperatures rapidly increased. We also found that the climate warming trend was strong and statistically significant. Compared with the reconstructed Little Ice Age temperatures in late eighteenth century cooling culmination, the present day summer temperatures are >4 degrees C higher and the temperature increase since the 1930s has been 0.5 degrees C per decade. These results highlight the exceptionally rapid recent warming of southern Svalbard and add invaluable information on the seasonality of High Arctic climate change and Arctic amplification.
  • Lyra, Christina; Sinkko, Hanna-Mari; Rantanen, Matias; Paulin, Lars; Kotilainen, Aarno (2013)
  • La Mere, Kelsey Maggan; Mäntyniemi, Samu; Haapasaari, Päivi (2020)
    In the Baltic Sea region, salmon are valued for the ecological, economic, and cultural benefits they provide. However, these fish are threatened due to historical overfishing, disease, and reduced access to spawning rivers. Climate change may pose another challenge for salmon management. Therefore, we conducted a problem-framing study to explore the effects climate change may have on salmon and the socio-ecological system they are embedded within. Addressing this emerging issue will require the cooperation of diverse stakeholders and the integration of their knowledge and values in a contentious management context. Therefore, we conducted this problem framing as a participatory process with stakeholders, whose mental models and questionnaire responses form the basis of this study. By framing the climate change problem in this way, we aim to provide a holistic understanding of the problem and incorporate stakeholder perspectives into the management process from an early stage to better address their concerns and establish common ground. We conclude that considering climate change is relevant for Baltic salmon management, although it may not be the most pressing threat facing these fish. Stakeholders disagree about whether climate change will harm or benefit salmon, when it will become a relevant issue in the Baltic context, and whether or not management efforts can mitigate any negative impacts climate change may have on salmon and their fishery. Nevertheless, by synthesizing the stakeholders' influence diagrams, we found 15 themes exemplifying: (1) how climate change may affect salmon, (2) goals for salmon management considering climate change, and (3) strategies for achieving those goals. Further, the stakeholders tended to focus on the riverine environment and the salmon life stages occurring therein, potentially indicating the perceived vulnerability of these life stages to climate change. Interestingly, however, the stakeholders tended to focus on traditional fishery management measures, like catch quotas, to meet their goals for these fish considering climate change. Further, social variables, like “politics,” “international cooperation,” and “employment” comprised a large proportion of the stakeholders' diagrams, demonstrating the importance of these factors for salmon management.
  • Luoto, Tomi P.; Rantala, Marttiina V.; Tammelin, Mira H. (2017)
    We examined a sediment record from Lake Hiidenvesi in southern Finland using paleolimnological methods to trace its limnoecological history. In our record, beginning from the 1940s, chironomid (Diptera) assemblages shifted from typical boreal taxa towards mesotrophic community assemblages at similar to 1960-1980 CE being finally replaced by eutrophic taxa from the 1990s onward. The diatom (Bacillariophyceae) assemblages reflected relatively nutrient rich conditions throughout the record showing a further increase in eutrophic taxa from the 1970s onward. A chironomid-based reconstruction of late-winter hypolimnetic dissolved oxygen (DO) conditions suggested anoxic conditions already in the 1950s, probably reflecting increased inlake production due to allochthonous nutrient inputs and related increase in biological oxygen consumption. However, the reconstruction also indicated large variability in long-term oxygen conditions that appear typical for the basin. With regard to nutrient status, chironomid- and diatom-based reconstructions of total phosphorus (TP) showed a similar trend throughout the record, although, chironomids indicated a more straightforward eutrophication process in the benthic habitat and seemed to reflect the intensified human activities in the catchment more strongly than diatoms. The DO and TP reconstructions were mostly similar in trends compared to the measured data available since the 1970s/1980s. However, the increase in TP during the most recent years in both reconstructions was not visible in the monitored data. The results of our multiproxy study emphasize the significance of including both epilimnetic and hypolimnetic systems in water quality assessments and provide important long-term limnoecological information that will be useful in the future when setting targets for restoration.
  • Helmens, Karin; Katrantsiotis , Christos; Salonen, Jaakko Sakari; Shala, Shyhrete; Bos, Johanna; Engels, Stefan; Kuosmanen, Niina; Luoto, Tomi P.; Väliranta, Minna Maria; Luoto, Miska; Ojala, Antti; Risberg, Jan; Weckström, Jan Björn (2018)
    Detailed studies on fossil remains of plants or animals in glacial lake sediments are rare. As a result, environmental conditions right at the moment of deglaciation of the large N-Hemisphere ice-sheets remain largely unknown. Here we study three deglacial phases of the Fennoscandian Ice Sheet as a unique, repeated element in a long sediment record preserved at Sokli in northern Finland. We summarize extensive multi-proxy data (diatoms, phytoliths, chironomids, pollen, spores, non-pollen palynomorphs, macrofossils, lithology, loss-on-ignition, C/N) obtained on glacial lake sediments dated to the early Holocene (ca. 10 kyr BP), early MIS 3 (ca. 50 kyr BP) and early MIS 5a (ca. 80 kyr BP). In contrast to the common view of an unproductive ice-marginal environment, our study reconstructs rich ecosystems both in the glacial lake and along the shores with forest on recently deglaciated land. Higher than present-day summer temperatures are reconstructed based on a large variety of aquatic taxa. Rich biota developed due to the insolation-induced postglacial warming and high nutrient levels, the latter resulting from erosion of fresh bedrock and sediment, leaching of surface soils, decay of plant material under shallow water conditions, and sudden decreases in lake volume. Aquatic communities responded quickly to deglaciation and warm summers and reflect boreal conditions, in contrast to the terrestrial ecosystem which responded with some delay probably due to time required for slow soil formation processes. Birch forest is reconstructed upon deglaciation of the large LGM ice-sheet and shrub tundra following the probably faster melting smaller MIS 4 and MIS 5b ice-sheets. Our study shows that glacial lake sediments can provide valuable palaeo-environmental data, that aquatic biota and terrestrial vegetation rapidly accommodated to new environmental conditions during deglaciation, and that glacial lake ecosystems, and the carbon stored in their sediments, should be included in earth system modeling.