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Karolina Stenroth Lina E. Polvi Emma Fältström Micael Jonsson 《Freshwater Biology》2015,60(1):136-149
- We assessed the influence of agricultural land use on aquatic–terrestrial linkages along streams arising from changes in the emergence of aquatic insects. We expected that terrestrial predators would respond to a change in the abundance and/or the size structure of the emerging aquatic insects by an increase or decrease in population size.
- We measured the flux of emergent aquatic insects and the abundance of terrestrial invertebrate predators and birds along 10 streams across a forest‐to‐agriculture land‐use gradient. We also performed stable isotope analyses (hydrogen, carbon and nitrogen) of terrestrial invertebrate predators.
- Small aquatic insects (Nematocera) were most abundant under agricultural land use, whereas larger bodied aquatic insects (Plecoptera and Trichoptera) were more associated with forest land use. Carabid beetles and linyphiid spiders were associated with agricultural streams (where there was a high abundance of small aquatic insects), whereas lycosid spiders and birds were associated with forest streams and a high abundance of large‐sized aquatic insects.
- The contribution of aquatic insects to the diets of riparian Lycosidae, Linyphiidae and Carabidae was estimated to be 44%, 60% and 43%, respectively, indicating the importance of aquatic subsidies to the terrestrial system.
- Our results show that agricultural land use in an overall forested landscape can have significant effects on the abundance and diet of terrestrial consumers through its impact on the size structure of the assemblage of emerging insects, rather than the overall magnitude (numbers) of the aquatic subsidy. Hence, our results suggest that the composition, not just quantity, of a cross‐habitat resource may influence the recipient system.
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Lovisa Lind Christer Nilsson Lina E. Polvi Christine Weber 《Biological reviews of the Cambridge Philosophical Society》2014,89(4):791-804
Ice dynamics is an important factor affecting vegetation in high‐altitude and high‐latitude streams and rivers. During the last few decades, knowledge about ice in streams and rivers has increased significantly and a respectable body of literature is now available. Here we review the literature on how ice dynamics influence riparian and aquatic vegetation. Traditionally, plant ecologists have focused their studies on the summer period, largely ignoring the fact that processes during winter also impact vegetation dynamics. For example, the freeze‐up period in early winter may result in extensive formation of underwater ice that can restructure the channel, obstruct flow, and cause flooding and thus formation of more ice. In midwinter, slow‐flowing reaches develop a surface‐ice cover that accumulates snow, protecting habitats under the ice from formation of underwater ice but also reducing underwater light, thus suppressing photosynthesis. Towards the end of winter, ice breaks up and moves downstream. During this transport, ice floes can jam up and cause floods and major erosion. The magnitudes of the floods and their erosive power mainly depend on the size of the watercourse, also resulting in different degrees of disturbance to the vegetation. Vegetation responds both physically and physiologically to ice dynamics. Physical action involves the erosive force of moving ice and damage caused by ground frost, whereas physiological effects – mostly cell damage – happen as a result of plants freezing into the ice. On a community level, large magnitudes of ice dynamics seem to favour species richness, but can be detrimental for individual plants. Human impacts, such as flow regulation, channelisation, agriculturalisation and water pollution have modified ice dynamics; further changes are expected as a result of current and predicted future climate change. Human impacts and climate change can both favour and disfavour riverine vegetation dynamics. Restoration of streams and rivers may mitigate some effects of anticipated climate change on ice and vegetation dynamics by, for example, slowing down flows and increasing water depth, thus reducing the potential for massive formation of underwater ice. 相似文献
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The configuration of channels in stream networks is vital for their connectivity, biodiversity, and metacommunity dynamics. We compared the capacity of three process domains—lakes, slow‐flowing reaches, and rapids—to disperse and retain plant propagules by releasing small wooden cubes as propagule mimics during the spring flood and recording their final locations. We also measured the geomorphic characteristics (planform, longitudinal profile, cross‐sectional morphology, and wood) of each process domain. The three process domains all differed in morphology and hydraulics, and those characteristics were important in shaping the transport capacity of mimics. On average, lakes retained more mimics than slow‐flowing reaches but did not differ from the retainment of rapids. Living macrophytes were the most efficient element trapping mimics. In rapids and slow‐flowing reaches, most trapped mimics remained floating, whereas in lakes, most mimics ended up on the banks. The decay curves of retention varied substantially among and within process domains. The results suggest that managers who rely on natural recovery of restored sites by means of plant immigration may benefit from understanding landscape patterns when deciding upon the location of restoration measures in stream networks. 相似文献
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Xiaolei Su Lina E. Polvi Lovisa Lind Francesca Pilotto Christer Nilsson 《Freshwater Biology》2019,64(5):1015-1028
- We tested whether the recovery of riparian vegetation along rapids that have been restored after channelisation for timber floating can be predicted based on floristic and geomorphic characteristics of surrounding landscape units. Our study was located along tributary stream networks, naturally fragmented in rapids, slow‐flowing reaches, and lakes (i.e. process domains), in the Vindel River catchment in northern Sweden.
- We tested whether landscape characteristics, specifically to what extent the geomorphology (affecting local abiotic conditions), species richness, and species composition (representing the species pool for recolonisation), as well as the proximity to various upstream process domains (determining the dispersal potential), can predict post‐restoration recovery of riparian vegetation.
- Our results indicate that post‐restoration recovery of riparian vegetation richness or composition is not strongly related to landscape‐scale species pools in these streams. The restored rapids were most similar to upstream rapids, geomorphically and floristically, including plant traits. Species richness of adjacent landscape units (upstream process domains or lateral upland zone) did not correlate with that of restored rapids, and proximity of upstream rapids or other process domains was only weakly influential, thus diminishing support for the hypothesis that hydrochory or other means of propagule dispersal plays a strong role in riparian vegetation community organisation after restoration in this fragmented stream network.
- We conclude that, in these naturally fragmented stream systems with three discrete process domains (rapids, slow‐flowing reaches and lakes), hydrochory is probably not the main predictor for short‐term riparian vegetation recovery. Therefore, other factors than landscape context can serve in prioritising restoration and, in these systems, local factors are likely to outweigh landscape connectivity in the recovery of riparian vegetation.
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Nilsson Christer Sarneel Judith M. Palm Daniel Gardeström Johanna Pilotto Francesca Polvi Lina E. Lind Lovisa Holmqvist Daniel Lundqvist Hans 《Ecosystems》2017,20(1):144-162
Ecosystems - Restoration of channelized streams by returning coarse sediment from stream edges to the wetted channel has become a common practice in Sweden. Yet, restoration activities do not... 相似文献
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Polvi A Linnankivi T Kivelä T Herva R Keating JP Mäkitie O Pareyson D Vainionpää L Lahtinen J Hovatta I Pihko H Lehesjoki AE 《American journal of human genetics》2012,90(3):540-549
Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is a rare multisystem disorder characterized by extensive intracranial calcifications and cysts, leukoencephalopathy, and retinal vascular abnormalities. Additional features include poor growth, skeletal and hematological abnormalities, and recurrent gastrointestinal bleedings. Autosomal-recessive inheritance has been postulated. The pathogenesis of CRMCC is unknown, but its phenotype has key similarities with Revesz syndrome, which is caused by mutations in TINF2, a gene encoding a member of the telomere protecting shelterin complex. After a whole-exome sequencing approach in four unrelated individuals with CRMCC, we observed four recessively inherited compound heterozygous mutations in CTC1, which encodes the CTS telomere maintenance complex component 1. Sanger sequencing revealed seven more compound heterozygous mutations in eight more unrelated affected individuals. Two individuals who displayed late-onset cerebral findings, a normal fundus appearance, and no systemic findings did not have CTC1 mutations, implying that systemic findings are an important indication for CTC1 sequencing. Of the 11 mutations identified, four were missense, one was nonsense, two resulted in in-frame amino acid deletions, and four were short frameshift-creating deletions. All but two affected individuals were compound heterozygous for a missense mutation and a frameshift or nonsense mutation. No individuals with two frameshift or nonsense mutations were identified, which implies that severe disturbance of CTC1 function from both alleles might not be compatible with survival. Our preliminary functional experiments did not show evidence of severely affected telomere integrity in the affected individuals. Therefore, determining the underlying pathomechanisms associated with deficient CTC1 function will require further studies. 相似文献
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Kennedy LJ Altet L Angles JM Barnes A Carter SD Francino O Gerlach JA Happ GM Ollier WE Polvi A Thomson W Wagner JL 《Animal genetics》2000,31(1):52-61
A Nomenclature committee for Factors of the Dog Major Histocompatibility System or Dog Leukocyte Antigen (DLA) has been convened under the auspices of the International Society for Animal Genetics (ISAG) to define a sequence based nomenclature for the genes of the DLA system. The remit of this committee includes: assignment of gene names rules for naming alleles assignment of names to published alleles assignment of names to new alleles rules for acceptance of new alleles DLA Nomenclature Committee, rules for acceptance, DLA genes and alleles, sequence based nomenclature. 相似文献
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Dolly Jørgensen Christer Nilsson Anouschka R. Hof Eliza M. Hasselquist Susan Baker F. Stuart Chapin III Katarina Eckerberg Joakim Hjältén Lina Polvi Laura A. Meyerson 《Restoration Ecology》2014,22(1):1-4
Relating restoration ecology to policy is one of the aims of the Society for Ecological Restoration and its journal Restoration Ecology. As an interdisciplinary team of researchers in both ecological science and political science, we have struggled with how policy‐relevant language is and could be deployed in restoration ecology. Using language in scientific publications that resonates with overarching policy questions may facilitate linkages between researcher investigations and decision‐makers' concerns on all levels. Climate change is the most important environmental problem of our time and to provide policymakers with new relevant knowledge on this problem is of outmost importance. To determine whether or not policy‐specific language was being included in restoration ecology science, we surveyed the field of restoration ecology from 2008 to 2010, identifying 1,029 articles, which we further examined for the inclusion of climate change as a key element of the research. We found that of the 58 articles with “climate change” or “global warming” in the abstract, only 3 identified specific policies relevant to the research results. We believe that restoration ecologists are failing to include themselves in policy formation and implementation of issues such as climate change within journals focused on restoration ecology. We suggest that more explicit reference to policies and terminology recognizable to policymakers might enhance the impact of restoration ecology on decision‐making processes. 相似文献
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