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  • Buckland, Philip I., 1973-, et al. (författare)
  • BugsCEP, an entomological database twenty-five years on
  • 2014
  • Ingår i: Antenna (Journal of the Royal Entomological Society). - London : Royal Entomological Society of London. - 0140-1890. ; 38:1, s. 21-28
  • Tidskriftsartikel (refereegranskat)
  • Sernland, Emma (författare)
  • Optimal strategies and information in foraging theory
  • 2005
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • In this thesis, I present both theoretical and empirical work where we have studied how humans and animals use information in situations where they need to continually update their information on the density of a resource. We have found that the amount of information, and the way the information is presented, are important factors for how well decisions are adapted to current circumstances. In an empirical study on humans, we found that humans seem to have a default idea of the distribution of a resource. This default idea seems to be plastic, i.e. it is adjusted according to incoming information. The way additional information was presented, as well as the information content, was important for how well the default idea was adjusted to current circumstances.By using mathematical models, we have also studied whether access to information from group members, so called public information, is one of the reasons why some species live in groups. When group members aim to maximize its intake rate of food and share both information and food items found equally, and when each individual has to pay all the cost for travelling between foraging patches, the intake rate of food will decrease with increasing group size. The animals will spend a larger proportion of the time on travelling between patches and less time on foraging the larger the group size. In this case, information sharing on food density in patches is not a reason why animals live in groups.We have also used mathematical models to study the information dynamics in a group of foraging animals that cannot both search for food and information at the same time. The animals aim to maximize their survival, and are given three behavioural choices in each time step: stay and search for food, stay and scan for information, or leave the current patch. The results show that the choice of behaviour depends on the energy reserves of the individual. An animal with low energy reserves searches for food and leaves the patch if its assessment of potential patch quality decreases to a certain level. An animal with high energy reserves chooses to stay in the patch and scan for information. In our model we assume that when one individual leaves the patch, the rest of the group also leaves. This means that it is those individuals that have low energy reserves that will make the leaving decisions for the group.In the end, we use these theories on Bayesian foraging, information updating and decision-making in order to develop a new type of effort-based quota for sustainable fisheries management: an effort-based dynamic quota (EDQ). We show that by using information from ongoing fishing combined with fishing data from earlier years, we can reach a higher maximum sustainable yield compared to using a total allowable catch (TAC).
  • Caputo, Andrea, 1988- (författare)
  • Genomic and morphological diversity of marine planktonic diatom-diazotroph associations : a continuum of integration and diversification through geological time
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • Symbioses between eukaryotes and nitrogen (N2)-fixing cyanobacteria (or diazotrophs) are quite common in the plankton community. A few genera of diatoms (Bacillariophyceae) such as Rhizosolenia, Hemiaulus and Chaetoceros are well known to form symbioses with the heterocystous diazotrophic cyanobacteria Richelia intracellularis and Calothrix rhizosoleniae. The latter are also called diatom-diazotroph associations, or DDAs. Up to now, the prokaryotic partners have been morphologically and genetically characterized, and the phylogenetic reconstruction of the well conserved nifH gene (encodes for the nitrogenase enzyme) placed the symbionts in 3 clusters based on their host-specificity, i.e. het-1 (Rhizosolenia-R. intracellularis), het-2 (Hemiaulus-R. intracellularis), and het-3 (Chaetoceros-C- rhizosoleniae). Conversely, the diatom-hosts, major representative of the phytoplankton community and crucial contributors to the carbon (C) biogeochemical cycle, have been understudied.The first aim of this thesis was to genetically and morphologically characterize the diatom-hosts, and to reconstruct the evolutionary background of the partnerships and the symbiont integration in the host. The molecular-clock analysis reconstruction showed the ancient appearance of the DDAs, and the traits characterizing the ancestors. In addition, diatom-hosts bearing internal symbionts (with more eroded draft genomes) appeared earlier than diatom-hosts with external symbionts. Finally a blast survey highlighted a broader distribution of the DDAs than expected.The second aim of this thesis was to compare genetic and physiological characteristics of the DDAs symbionts with the other eukaryote-diazotroph symbiosis, i.e. prymnesiophyte-UCYN-A (or Candidatus Atelocyanobacterium thalassa). The genome comparison highlighted more genes for transporters in het-3 (external symbiont) and in the UCYN-A based symbiosis, suggesting that symbiont location might be relevant also for metabolic exchanges and interactions with the host and/or environment. Moreover, a summary of methodological biases that brought to an underestimation of the DDAs is reported.The third aim of this thesis was to determine the distribution of the DDAs in the South Pacific Ocean using a quantitative polymerase chain reaction (qPCR) approach and to outline the environmental drivers of such distribution. Among the het-groups, het-1 was the most abundant/detected and co-occurred with the other 2 symbiotic strains, all responding similarly to the influence of abiotic factors, such as temperature and salinity (positive and negative correlation, respectively). Globally, Trichodesmium dominated the qPCR detections, followed by UCYN-B. UCYN-A phylotypes (A-1, A-2) were detected without their proposed hosts, for which new oligonucleotides were designed. The latter suggested a facultative symbiosis. Finally, microscopy observations of the het-groups highlighted a discrepancy with the qPCR counts (i.e. the former were several order of magnitudes lower), leading to the idea of developing a new approach to quantify the DDAs.  The fourth aim of this thesis was to develop highly specific in situ hybridization assays (CARD-FISH) to determine the presence of alternative life-stages and/or free-living partners. The new assays were applied to samples collected in the South China Sea and compared with abundance estimates from qPCR assays for the 3 symbiotic strains. Free-living cells were indeed detected along the transect, mainly at deeper depths. Free-living symbionts had two morphotypes: trichomes and single-cells. The latter were interpreted as temporary life-stages. Consistent co-occurrence of the 3 het-groups was also found in the SCS and application of a SEM model predicted positive interactions between the het groups. We interpreted the positive interaction as absence of intra-specific competition, and consistent with the previous study, temperature and salinity were predicted as major drivers of the DDAs distribution.
  • Vickers, Kim, et al. (författare)
  • Predicting island beetle faunas by their climate ranges : the tabula rasa/refugia theory in the North Atlantic
  • 2015
  • Ingår i: Journal of Biogeography. - : Wiley-Blackwell. - 0305-0270 .- 1365-2699. ; 42:11, s. 2031-2048
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: This paper addresses two opposing theories put forward for the origins of the beetle fauna of the North Atlantic islands. The first is that the biota of the isolated oceanic islands of the Faroes, Iceland and Greenland immigrated across a Palaeogene–Neogene land bridge from Europe, and survived Pleistocene glaciations in ameliorated refugia. The second argues for a tabula rasa in which the biota of the islands was exterminated during glaciations and is Holocene in origin. The crux of these theories lies in the ability of the flora and fauna to survive in a range of environmental extremes. This paper sets out to assess the viability of the refugia hypothesis using the climatic tolerances of one aspect of the biota: the beetle fauna. Location: The paper focuses on Iceland, the Faroe Islands and Greenland. Methods: The known temperature requirements of the recorded beetle faunas of the North Atlantic islands were compared with published proxy climate reconstructions for successive climate periods since the severing of a North Atlantic land bridge. We used the MCR (mutual climatic range) method available in the open access BugsCEP database software. Results: We show that most of the MCR faunas of the North Atlantic islands could not have survived in situ since the Palaeogene–Neogene, and are likely to have been exterminated by the Pleistocene glaciations. Main conclusions: The discrepancy between the climatic tolerances of the North Atlantic beetle fauna and the estimated climatic regimes since the severing of a land bridge strongly support the tabula rasa theory and suggests that the North Atlantic coleopteran fauna is Holocene in origin.
  • Karp, Daniel S., et al. (författare)
  • Crop pests and predators exhibit inconsistent responses to surrounding landscape composition
  • 2018
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Acad Sciences. - 1091-6490 .- 0027-8424. ; 115:33, s. 7863-7870
  • Tidskriftsartikel (refereegranskat)abstract
    • The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies. © 2018 National Academy of Sciences. All rights reserved.
  • Buckland, Philip I., 1973-, et al. (författare)
  • The Strategic Environmental Archaeology Database : a resource for international, multiproxy and transdisciplinary studies of environmental and climatic change
  • 2015
  • Konferensbidrag (refereegranskat)abstract
    • Climate and environmental change are global challenges which require global data and infrastructure to investigate. These challenges also require a multi-proxy approach, integrating evidence from Quaternary science and archaeology with information from studies on modern ecology and physical processes among other disciplines. The Strategic Environmental Archaeology Database (SEAD http://www.sead.se) is a Swedish based international research e-infrastructure for storing, managing, analysing and disseminating palaeoenvironmental data from an almost unlimited number of analysis methods. The system currently makes available raw data from over 1500 sites (>5300 datasets) and the analysis of Quaternary fossil insects, plant macrofossils, pollen, geochemistry and sediment physical properties, dendrochronology and wood anatomy, ceramic geochemistry and bones, along with numerous dating methods. This capacity will be expanded in the near future to include isotopes, multi-spectral and archaeo-metalurgical data. SEAD also includes expandable climate and environment calibration datasets, a complete bibliography and extensive metadata and services for linking these data to other resources. All data is available as Open Access through http://qsead.sead.se and downloadable software. SEAD is maintained and managed at the Environmental Archaeology Lab and HUMlab at Umea University, Sweden. Development and data ingestion is progressing in cooperation with The Laboratory for Ceramic Research and the National Laboratory for Wood Anatomy and Dendrochronology at Lund University, Sweden, the Archaeological Research Laboratory, Stockholm University, the Geoarchaeological Laboratory, Swedish National Historical Museums Agency and several international partners and research projects. Current plans include expanding its capacity to serve as a data source for any system and integration with the Swedish National Heritage Board's information systems. SEAD is partnered with the Neotoma palaeoecology database (http://www.neotomadb.org) and a new initiative for building cyberinfrastructure for transdisciplinary research and visualization of the long-term human ecodynamics of the North Atlantic funded by the National Science Foundation (NSF).
  • Figueroa, Daniela, et al. (författare)
  • Allochthonous Carbon-a Major Driver of Bacterioplankton Production in the Subarctic Northern Baltic Sea
  • 2016
  • Ingår i: Microbial Ecology. - : Springer. - 0095-3628 .- 1432-184X. ; 71:4, s. 789-801
  • Tidskriftsartikel (refereegranskat)abstract
    • Heterotrophic bacteria are, in many aquatic systems, reliant on autochthonous organic carbon as their energy source. One exception is low-productive humic lakes, where allochthonous dissolved organic matter (ADOM) is the major driver. We hypothesized that bacterial production (BP) is similarly regulated in subarctic estuaries that receive large amounts of riverine material. BP and potential explanatory factors were measured during May-August 2011 in the subarctic Råne Estuary, northern Sweden. The highest BP was observed in spring, concomitant with the spring river-flush and the lowest rates occurred during summer when primary production (PP) peaked. PLS correlations showed that ∼60 % of the BP variation was explained by different ADOM components, measured as humic substances, dissolved organic carbon (DOC) and coloured dissolved organic matter (CDOM). On average, BP was threefold higher than PP. The bioavailability of allochthonous dissolved organic carbon (ADOC) exhibited large spatial and temporal variation; however, the average value was low, ∼2 %. Bioassay analysis showed that BP in the near-shore area was potentially carbon limited early in the season, while BP at seaward stations was more commonly limited by nitrogen-phosphorus. Nevertheless, the bioassay indicated that ADOC could contribute significantly to the in situ BP, ∼60 %. We conclude that ADOM is a regulator of BP in the studied estuary. Thus, projected climate-induced increases in river discharge suggest that BP will increase in subarctic coastal areas during the coming century.
  • Lindkvist, Emilie, 1973-, et al. (författare)
  • Strategies for sustainable management of renewable resources during environmental change
  • 2017
  • Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - 0962-8452 .- 1471-2954. ; 284:1850
  • Tidskriftsartikel (refereegranskat)abstract
    • As a consequence of global environmental change, management strategies that can deal with unexpected change in resource dynamics are becoming increasingly important. In this paper we undertake a novel approach to studying resource growth problems using a computational form of adaptive management to find optimal strategies for prevalent natural resource management dilemmas. We scrutinize adaptive management, or learning-by-doing, to better understand how to simultaneously manage and learn about a system when its dynamics are unknown. We study important trade-offs in decision-making with respect to choosing optimal actions (harvest efforts) for sustainable management during change. This is operationalized through an artificially intelligent model where we analyze how different trends and fluctuations in growth rates of a renewable resource affect the performance of different management strategies. Our results show that the optimal strategy for managing resources with declining growth is capable of managing resources with fluctuating or increasing growth at a negligible cost, creating in a management strategy that is both efficient and robust towards future unknown changes. To obtain this strategy, adaptive management should strive for: high learning rates to new knowledge, high valuation of future outcomes and modest exploration around what is perceived as the optimal action.
  • Kylin, Henrik, et al. (författare)
  • Evaluating threats to an endangered species by proxy : air pollution as threat to the blue swallow (Hirundo atrocaerulea) in South Africa
  • 2011
  • Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 18:2, s. 282-290
  • Tidskriftsartikel (refereegranskat)abstract
    • Background, aim, and scope: The blue swallow (Hirundo atrocaerulea) is one of the most threatened bird species in southern Africa. Among terrestrial birds, its plumage is known to be the most water repellent, an adaptation to foraging on the wing in dense fog. Despite this uniqueadaptation, the nesting success of the blue swallow at the Blue Swallow Natural Heritage Site (BSNHS) is lower during years with high incidence of fog. As the phenomenon is not observed at other nesting sites, we hypothesized that this is due to changes in the air chemistry at the BSNHS. In the immediate proximity of the BSNHS, plantations of exotic trees (e.g., pines and eucalypts), rich in volatile organic compounds (VOCs), are dominant features. In addition, air pollution from the Johannesburg area is transported with the surface winds and mix withVOCs released from exotic trees. Together with the high humidity and high elevation, these conditions may result in the formation of sulphonates. Sulphonates are strong detergents, and the presence of these in the fog could lead to decreased water repellence of the plumage. This study was performed in order to determine the occurrence and distribution of sulphonates in the BSNHS and to compare these with sulphonates formed in other locations in South Africa. Because the blue swallow is endangered, pine needles were used as proxy to detect formation of sulphonates.Methods: We sampled pine needles with different exposure to air pollutants, in climates with different humidity, and at different elevation and analyzed these for sulphonates using mass spectrometry.Results: Pine needles from high elevations and the BSNHS, with high humidity, and exposure to air pollution contained significantly higher concentrations of sulphonates than pine needles from low elevations or from high elevations with a dryer climate or a different combination of air pollutants.Conclusions: These findings lead to two conclusions. First, the occurrence and distribution of sulphonates may be explained by chemical reactions between sulphur dioxide and organic compounds in the humid air induced by ultraviolet radiation. Second, elevated concentrations of sulphonates in the fog could affect the water repellence of the blue swallow plumage, possibly decreasing their capacity to forage in the fog. We cannot prove conclusively that this is the reason why the number of blue swallows atthe BSNHS has decreased dramatically, but for endangered species, we may have to rely on proxies to draw conclusions about outside threats. All such information should be valuable in devising protection plans for species under threat.Recommendations and perspectives: The use of proxies to elucidate threats to endangered species should be evaluated in a broad scale. The mist-belt habitat in general is threatened by many human activities. These findings indicate that air pollution and the proximity of volatile organic compound (VOC) sources close to mist-belt habitat refuges may be an unrecognised conservation threat to the animals inhabiting them.
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