SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "AMNE:(NATURVETENSKAP Biologiska vetenskaper Ekologi) ;lar1:(hkr)"

Sökning: AMNE:(NATURVETENSKAP Biologiska vetenskaper Ekologi) > Högskolan Kristianstad

  • Resultat 1-10 av 83
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Jönsson, K. Ingemar, 1959-, et al. (författare)
  • Sexual patterns of prebreeding energy reserves in the common frog Rana temporaria along a latitudinal gradient
  • 2009
  • Ingår i: Ecography. - : Wiley-Blackwell. - 0906-7590 .- 1600-0587. ; 32:5, s. 831-839
  • Tidskriftsartikel (refereegranskat)abstract
    • The ability to store energy is an important life history trait for organisms facing long periods without energy income, and in particular for capital breeders such as temperate zone amphibians, which rely on stored energy during reproduction. However, large scale comparative studies of energy stores in populations with different environmental constraints on energy allocation are scarce. We investigated energy storage patterns in spring (after hibernation and before reproduction) in eight common frog (Rana temporaria) populations exposed to different environmental conditions along a 1600 km latitudinal gradient across Scandinavia (range of annual activity period 3-7 months). Analyses of lean body weight (eviscerated body mass), weight of fat bodies, liver weight, and liver fat content, showed that (i) post-hibernation/pre-breeding energy stores increased with increasing latitude in both sexes, (ii) males generally had larger energy reserves than females and (iii) the difference in energy stores between sexes decreased towards the north. Larger energy reserves towards the north can serve as a buffer against less predictable and/or less benign weather conditions during the short activity period, and may also represent a risk-averse tactic connected with a more pronounced iteroparous life history. In females, the continuous and overlapping vitellogenic activity in the north may also demand more reserves in early spring. The general sexual difference could be a consequence of the fact that, at the time of our sampling, females had already invested their energy into reproduction in the given year (i.e. their eggs were already ovulated), while the males' main reproductive activities (e.g. calling, mate searching, sexual competition) occurred later in the season.
  •  
2.
  • Schill, Ralph O., et al. (författare)
  • Food of tardigrades : a case study to understand food choice, intake and digestion
  • 2011
  • Ingår i: Journal of Zoological Systematics and Evolutionary Research. - 0947-5745 .- 1439-0469. ; 49:Suppl. 1, s. 66-70
  • Tidskriftsartikel (refereegranskat)abstract
    • Mosses are an excellent habitat for tardigrades because of their ability to ensure a high humidity and to provide a rich food supply for both carnivorous and herbivorous species. Food choice can be correlated with the morphology of the buccal apparatus, and consequentially, their distribution is sometimes linked to food availability (nematodes, rotifers, plant cells, algae, yeast and bacteria). In many species, material containing chlorophyll is often observed in the midgut. However, little information has been available until now on the actual food preference of tardigrades. Since trophic interactions within soil food webs are difficult to study, here we use a polymerase chain reaction–based approach as a highly sensitive detection method. The study was carried out to investigate the presence of chlorophyll matter in the gut of active specimens, based on sequence analyses of the chloroplast ribulose 1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) gene from mosses and algae. The sequences found in the gut of Macrobiotus sapiens were derived from the moss families Pottiaceae and Erpodiaceae, in Macrobiotus persimilis and Echiniscus granulatus from the moss family Grimmiaceae, and in Richtersius coronifer from the green algae genus Trebouxia. Furthermore, we show the emission of green autofluorescence from the chloroplasts in the algae within the gut of tardigrades and followed the progress of digestion over a 48-h period. The autofluorescent emission level declined significantly, and after 2 days, the signal level was similar to the level of the starved control.
  •  
3.
  • Gillman, Anna, et al. (författare)
  • Oseltamivir-Resistant Influenza A (H1N1) Virus Strain with an H274Y Mutation in Neuraminidase Persists without Drug Pressure in Infected Mallards
  • 2015
  • Ingår i: Applied and Environmental Microbiology. - : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 81:7, s. 2378-2383
  • Tidskriftsartikel (refereegranskat)abstract
    • Influenza A virus (IAV) has its natural reservoir in wild waterfowl and emerging human IAVs often contain gene segments from avian viruses. The active drug metabolite of oseltamivir (oseltamivir carboxylate (OC)), stockpiled as Tamiflu® for influenza pandemic preparedness, is not removed by conventional sewage treatment and has been detected in river water. There, it may there exert evolutionary pressure on avian IAV in waterfowl, resulting in development of resistant viral variants. A resistant avian IAV can circulate among wild birds only if resistance does not restrict viral fitness and if the resistant virus can persist without continuous drug pressure. In this in vivo Mallard (Anas platyrhynchos) study we tested if an OC-resistant avian IAV strain (A(H1N1)/NA-H274Y) could retain resistance while drug pressure was gradually removed. Successively infected Mallards were exposed to decreasing levels of OC, and fecal samples were analyzed for neuraminidase sequence and phenotypic resistance. No reversion to wild-type virus was observed during the experiment, which included 17 days of viral transmission in 10 ducks exposed to OC concentrations below resistance induction levels. We conclude that resistance in avian IAV, induced by OC exposure of the natural host, can persist in absence of the drug. Thus, there is a risk that human pathogenic IAVs that evolve from IAVs circulating among wild birds may contain resistance mutations. An oseltamivir resistant pandemic IAV would be a substantial public health threat. Therefore, our observations underscore the need for prudent oseltamivir use, upgraded sewage treatment and resistance surveillance of IAV in wild birds.
  •  
4.
  • Tolf, Conny, et al. (författare)
  • Individual variation in influenza A virus infection histories and long-term immune responses in mallards
  • 2013
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:4, s. e61201-
  • Tidskriftsartikel (refereegranskat)abstract
    • Wild dabbling ducks (genus Anas) are the main reservoir for influenza A virus (IAV) in the Northern Hemisphere. Current understanding of disease dynamics and epidemiology in this virus-host system has primarily been based on populationlevel ,surveillance studies and infection experiments conducted in laboratory settings. Using a combined experimentalnatural approach with wild-strain captive mallards (Anas platyrhynchos), we monitored individual IAV infection histories and immunological responses of 10 birds over the course of 15 months. This is the first detailed study to track natural IAV infection histories over several seasons amongst the same individuals growing from juvenile to adults. The general trends in the infection histories of the monitored birds reflected seasonal variation in prevalence at the population level. However, within the study group there were significant differences between individuals in infection frequency as well as in short and long term anti-IAV antibody response. Further observations included individual variation in the number of infecting virus subtypes, and a strong tendency for long-lasting hemagglutinin-related homosubtypic immunity. Specifically, all infections in the second autumn, except one, were of different subtypes compared to the first autumn. The variation among birds concerning these epidemiologically important traits illustrates the necessity for IAV studies to move from the level of populations to examine individuals in order to further our understanding of IAV disease and epidemiology.
  •  
5.
  • Alho, Jussi S., et al. (författare)
  • Increasing melanism along a latitudinal gradient in a widespread amphibian : local adaptation, ontogenic or environmental plasticity?
  • 2010
  • Ingår i: BMC Evolutionary Biology. - 1471-2148 .- 1471-2148. ; 10, s. 317-
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundThe thermal benefits of melanism in ectothermic animals are widely recognized, but relatively little is known about population differentiation in the degree of melanism along thermal gradients, and the relative contributions of genetic vs. environmental components into the level of melanism expressed. We investigated variation in the degree of melanism in the common frog (Rana temporaria; an active heliotherm thermoregulator) by comparing the degree of melanism (i) among twelve populations spanning over 1500 km long latitudinal gradient across the Scandinavian Peninsula and (ii) between two populations from latitudinal extremes subjected to larval temperature treatments in a common garden experiment.ResultsWe found that the degree of melanism increased steeply in the wild as a function of latitude. Comparison of the degree of population differentiation in melanism (PST) and neutral marker loci (FST) revealed that the PST > FST, indicating that the differences cannot be explained by random genetic drift alone. However, the latitudinal trend observed in the wild was not present in the common garden data, suggesting that the cline in nature is not attributable to direct genetic differences.ConclusionsAs straightforward local adaptation can be ruled out, the observed trend is likely to result from environment-driven phenotypic plasticity or ontogenetic plasticity coupled with population differences in age structure. In general, our results provide an example how phenotypic plasticity or even plain ontogeny can drive latitudinal clines and result in patterns perfectly matching the genetic differences expected under adaptive hypotheses. 
  •  
6.
  • Hedenas, Henrik, et al. (författare)
  • Changes Versus Homeostasis in Alpine and Sub-Alpine Vegetation Over Three Decades in the Sub-Arctic
  • 2012
  • Ingår i: Ambio. - : Springer Verlag (Germany). - 0044-7447 .- 1654-7209. ; 41, s. 187-196
  • Tidskriftsartikel (refereegranskat)abstract
    • Plant species distributions are expected to shift and diversity is expected to decline as a result of global climate change, particularly in the Arctic where climate warming is amplified. We have recorded the changes in richness and abundance of vascular plants at Abisko, sub-Arctic Sweden, by re-sampling five studies consisting of seven datasets; one in the mountain birch forest and six at open sites. The oldest study was initiated in 1977–1979 and the latest in 1992. Total species number increased at all sites except for the birch forest site where richness decreased. We found no general pattern in how composition of vascular plants has changed over time. Three species, Calamagrostis lapponica, Carex vaginata and Salix reticulata, showed an overall increase in cover/frequency, while two Equisetum taxa decreased. Instead, we showed that the magnitude and direction of changes in species richness and composition differ among sites.
  •  
7.
  • Söderquist, Pär, et al. (författare)
  • Wild Mallards have more ”goose-like” bills than their ancestors
  • 2015
  • Ingår i: 4th Pan-European Duck Symposium, Hangö, Finland, 7-11/4, 2015. ; , s. 38-
  • Konferensbidrag (refereegranskat)abstract
    • Wild populations of the world’s most common dabbling duck, the Mallard (Anas platyrhynchos), run the risk of genetic introgression by farmed conspecifics released for hunting purposes. We tested whether bill morphology of free-living birds has changed since large-scale releases of farmed Mallards started. Three groups of Mallards from Sweden, Norway and Finland were compared: historical wild (before large-scale releases started), present-day wild, and present-day farmed. Higher density of bill lamellae was observed in historical wild Mallards (only males). Farmed Mallards had wider bills than present-day and historical wild ones. Present-day wild and farmed Mallards also had higher and shorter bills than historical wild Mallards. Present-day Mallards thus tend to have more ‘‘goose-like’’ bills (wider, higher, and shorter) than their ancestors. Our study suggests that surviving released Mallards affect morphological traits in wild population by introgression. We discuss how such anthropogenic impact may lead to a maladapted and genetically compromised wild Mallard population. Our study system has bearing on other taxa where large-scale releases of conspecifics with ‘alien genes’ may cause a cryptic invasive process that nevertheless has fitness consequences for individual birds.
  •  
8.
  • Björklund, Erland, et al. (författare)
  • MORPHEUS success story Segesholmsån river and Degeberga WWTP, Skåne, Sweden
  • 2021
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • In the MORPHEUS project three Swedish Wastewater Treatment Plants (WWTPs) were investigated for their release of pharmaceuticals into the recipient. One of these was Degeberga WWTP which discharges its treated wastewater into the Segesholmsån river, ending in the Baltic Sea. Segesholmsån river has a length of 23 km and an average flow of roughly 0.6 m3/s (Figure 1).
  •  
9.
  • Strong, Emily A., et al. (författare)
  • Seeking greener pastures : crop selection by Greylag Geese (Anser anser) during the moulting season
  • 2021
  • Ingår i: Ornis Fennica. - : Finnish Omithological Soc. - 0030-5685. ; 98:1, s. 16-32
  • Tidskriftsartikel (refereegranskat)abstract
    • Over the last 40 years, many goose populations have recovered from historic lows and are now more numerous than ever. At the same time, geese have shifted from natural foraging habitats to securing most of their nutritional demands from agricultural fields, leading to crop damage and conflict with agriculture. We studied field use by Greylag Geese (Anser anser) in the agricultural landscape surrounding a main breeding and moulting lake in Sweden. From 2012 to 2016, weekly roadside surveys were conducted from May to July. Data were collected on goose numbers, crop type and sward height in agricultural fields. Using a compositional analysis, we demonstrate that Greylag Geese show a strong selection for ley and pasture fields compared to other crop types (rank order: ley/pasture > oat > barley > wheat > other crops). This selection was consistent across years and between pre- and post-moult. Aside from ley and pasture, no other croptypes were selected for, as they were used less than expected given their availability. Irrespective of crop type, geese foraged predominantly on short (0–10 cm) swards. The strong selection for ley and pasture may have been driven by higher nutritional quality of short, managed grass swards relative to other available foods. This suggests that during the summer grass fields may be more vulnerable to damage compared to other crop types. Our study provides a deeper understanding of the ecology of Greylag Geese, which may be used to inform management strategies focused on mitigating crop damage and alleviating conflict.
  •  
10.
  • Åkesson, Susanne, et al. (författare)
  • Autumn migratory orientation and route choice in early and late dunlins Calidris alpina captured at a stopover site in Alaska
  • 2021
  • Ingår i: Biology open. - : The Company of Biologists Ltd. - 2046-6390. ; 10:4, s. 1-10
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigated the migratory orientation of early and late captured dunlins, Calidris alpina, by recording their migratory activity in circular orientation cages during autumn at a staging site in southwest Alaska and performed route simulations to the wintering areas. Two races of dunlins breeding in Alaska have different wintering grounds in North America (Pacific Northwest), and East Asia. Dunlins caught early in autumn (presumably Calidris alpina pacifica) oriented towards their wintering areas (east-southeast; ESE) supporting the idea that they migrate nonstop over the Gulf of Alaska to the Pacific Northwest. We found no difference in orientation between adult and juveniles, nor between fat and lean birds or under clear and overcast skies demonstrating that age, energetic status and cloud cover did not affect the dunlins' migratory orientation. Later in autumn, we recorded orientation responses towards south-southwest suggesting arrival of the northern subspecies Calidris alpina arcticola at our site. Route simulations revealed multiple compass mechanisms were compatible with the initial direction of early dunlins wintering in the Pacific Northwest, and for late dunlins migrating to East Asia. Future high-resolution tracking would reveal routes, stopover use including local movements and possible course shifts during migration from Alaska to wintering sites on both sides of the north Pacific Ocean.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 83
Typ av publikation
tidskriftsartikel (44)
konferensbidrag (27)
bokkapitel (6)
rapport (3)
doktorsavhandling (1)
forskningsöversikt (1)
visa fler...
recension (1)
visa färre...
Typ av innehåll
refereegranskat (64)
övrigt vetenskapligt/konstnärligt (10)
populärvet., debatt m.m. (9)
Författare/redaktör
Gunnarsson, Gunnar (28)
Elmberg, Johan, 1960 ... (26)
Pöysä, Hannu (20)
Sjöberg, Kjell (19)
Nummi, Petri (18)
Elmberg, Johan (17)
visa fler...
Gunnarsson, Gunnar, ... (17)
Vought, Lena B. M. (10)
Söderquist, Pär (9)
Jönsson, K. Ingemar, ... (8)
Guillemain, Matthieu (8)
Lacoursière, Jean O. ... (8)
Arzel, Céline (7)
Waldenström, Jonas (6)
Dessborn, Lisa, 1976 ... (6)
Holopainen, Sari (6)
Olsen, Björn (4)
Månsson, Johan (4)
Fox, Anthony D. (4)
Latorre-Margalef, Ne ... (4)
Herczeg, Gábor (3)
Jönsson, Ingemar (3)
Champagnon, Jocelyn (3)
Björklund, Erland (2)
Thulin, Carl-Gustaf (2)
Söderman, Fredrik (2)
Merilä, Juha (2)
Merila, Juha (2)
Tolf, Conny (2)
Lehikoinen, Aleksi (2)
Järhult, Josef D (2)
Dessborn, Lisa (2)
Lacoursière, Jean O. (2)
Svahn, Ola, 1970- (2)
Gessner, Mark O. (2)
Kreisinger, Jakub (2)
Moller, Anders Pape (2)
Ferreira, Veronica (2)
Chauvet, Eric (2)
Tiegs, Scott D. (2)
Risnoveanu, Geta (2)
Dalby, Lars (2)
Hessel, Rebecca (2)
Liljebäck, Niklas (2)
Olsson, Camilla (2)
Väänänen, Veli-Matti (2)
Christensen, Thomas ... (2)
Holm, Thomas Eske (2)
Montras Janer, Teres ... (2)
Mckie, Brendan G. (2)
visa färre...
Lärosäte
Sveriges Lantbruksuniversitet (9)
Lunds universitet (7)
Linnéuniversitetet (3)
Umeå universitet (1)
Uppsala universitet (1)
visa fler...
Stockholms universitet (1)
Högskolan i Skövde (1)
visa färre...
Språk
Engelska (68)
Svenska (14)
Norska (1)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (83)
Lantbruksvetenskap (6)
Teknik (1)
Medicin och hälsovetenskap (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy