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  • 1. Aura, Christopher
    et al.
    Raburu, Philip
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Macroinvertebrates’ community structure in Rivers Kipkaren and Sosiani, River Nzoia basin, Kenya2011In: Journal of Ecology and the Natural Environment, ISSN 2006-9847, E-ISSN 2006-9847, Vol. 3, no 2, p. 39-46Article in journal (Refereed)
    Abstract [en]

    Benthic macroinvertebrates from Rivers Kipkaren and Sosiani in the upper reaches of River Nzoiabasin, Kenya, were sampled semi-quantitatively monthly from December 2006 to May 2007 using a0.5 mm mesh size scoop net in the riffles, pools and runs. Seven sampling sites were selected on theareas of the rivers along a longitudinal gradient in relation to anthropogenic impact. Physicochemicalparameters were measured in situ, while specific chemical parameters were determinedcalometrically in the laboratory using standard methods. Habitat and land use characteristics werealso recorded. A total of 1499 macroinvertebrates belonging to 13 orders, 28 families and 31 generawere collected. The orders Ephemeroptera, Hemiptera and Coleoptera were taxonomically richest.Overall, a total of 31 genera for River Kipkaren dominated by the EPT and 19 macroinvertebrategenera for the lower River Sosiani dominated by dipterans were recorded. Conductivity, oxygen andtotal nitrogen varied significantly (p < 0.05) between sampled sites, but not temporally. The results ofredundancy analysis using 9 dominant macroinvertebrate genera revealed a distinction betweenimpacted and the less impacted sites and the physico-chemical parameters associated with thisdistinction.

  • 2. Aura, CM
    et al.
    Raburu, PO
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    A preliminary macroinvertebrate Index of Biotic Integrity for Bioassessment of the Kipkaren and Sosiani Rivers Nzoia River Basin, Kenya.2010In: Lakes & Reservoirs: Research and Management, ISSN 1320-5331, E-ISSN 1440-1770, Vol. 15, no 2, p. 119-128Article in journal (Refereed)
    Abstract [en]

    Management efforts for the Lake Victoria Basin have been hampered by a lack of clear standards against which to judge the degree of environmental degradation, highlighting the need for a multi-metric approach for this purpose. Indeed, management priorities for the Lake Victoria catchment must be based on reliable assessments of the biological integrity of the inflowing rivers that can potentially influence the ecological functioning of the lake. Accordingly, macroinvertebrate metrics were evaluated for their responsiveness to human impacts, utilizing Pearson’s correlations with physico-chemical parameters. The resultant 9 metrics that provided the best discrimination between physico-chemical samples, using the separation power of Mann–Whitney U and Kolmogorov–Smirnov tests (P < 0.05) from the 21 sampling sites utilized in this study were the: (i) abundances of Ephemeroptera, Plecoptera and Trichoptera; (ii) relative abundances of Diptera; (iii) Ephemeroptera, Plecoptera and Trichoptera:Diptera ratio; (iv) Oligochaeta, Mollusca, Hemiptera, Odonata and the proportions of tolerance taxa; (v) dominant taxa; and (vi) the relative proportions of invertebrates that fall into the gatherer and predator feeding groups, based on the variability they exhibited across the sampling sites. Using the inter-quartile ranges to establish the scoring criteria, the index was able to delineate impacted from less-impacted sites along the rivers, providing preliminary evidence of responses to changes in the ecosystem integrity exhibited by resident macroinvertebrate assemblages in both rivers.

  • 3. Bergsten, Johannes
    et al.
    Bilton, David T.
    Fujisawa, Tomochika
    Elliott, Miranda
    Monaghan, Michael T.
    Balke, Michael
    Hendrich, Lars
    Geijer, Joja
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Foster, Garth N.
    Ribera, Ignacio
    Nilsson, Anders N.
    Barraclough, Timothy G.
    Vogler, Alfried P.
    The Effect of Geographical Scale of Sampling on DNA Barcoding2012In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 61, no 5, p. 851-869Article in journal (Refereed)
    Abstract [en]

    Eight years after DNA barcoding was formally proposed on a large scale, CO1 sequences are rapidly accumulating from around the world. While studies to date have mostly targeted local or regional species assemblages, the recent launch of the global iBOL project (International Barcode of Life), highlights the need to understand the effects of geographical scale on Barcoding's goals. Sampling has been central in the debate on DNA Barcoding, but the effect of the geographical scale of sampling has not yet been thoroughly and explicitly tested with empirical data. Here, we present a CO1 data set of aquatic predaceous diving beetles of the tribe Agabini, sampled throughout Europe, and use it to investigate how the geographic scale of sampling affects 1) the estimated intraspecific variation of species, 2) the genetic distance to the most closely related heterospecific, 3) the ratio of intraspecific and interspecific variation, 4) the frequency of taxonomically recognized species found to be monophyletic, and 5) query identification performance based on 6 different species assignment methods. Intraspecific variation was significantly correlated with the geographical scale of sampling (R-square = 0.7), and more than half of the species with 10 or more sampled individuals (N = 29) showed higher intraspecific variation than 1%, sequence divergence. In contrast, the distance to the closest heterospecific showed a significant decrease with increasing geographical scale of sampling. The average genetic distance dropped from >7% for samples within 1 km, to <3.5% for samples up to >6000 km apart. Over a third of the species were not monophyletic, and the proportion increased through locally, nationally, regionally, and continentally restricted subsets of the data. The success of identifying queries decreased with increasing spatial scale of sampling; liberal methods declined from 100% to around 90%, whereas strict methods dropped to below 50% at continental scales. The proportion of query, identifications considered uncertain (more than one species <1% distance from query) escalated from zero at local, to 50% at continental scale. Finally, by resampling the most widely sampled species we show that even if samples are collected to maximize the geographical coverage, up to 70 individuals are required to sample 95%, of intraspecific variation. The results show that the geographical scale of sampling has a critical impact on the global application of DNA barcoding. Scale-effects result from the relative importance of different processes determining the composition of regional species assemblages (dispersal and ecological assembly) and global clades (demography, speciation, and extinction). The incorporation of geographical information, where available, will be required to obtain identification rates at global scales equivalent to those in regional barcoding studies. Our result hence provides an impetus for both smarter barcoding tools and sprouting national barcoding initiatives smaller geographical scales deliver higher accuracy.

  • 4. Bjelke, Ulf
    et al.
    Bohman, Irene
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Herrmann, Jan
    Temporal niches of shredders in lake littorals with possible implications on ecosystem functioning2005In: Aquatic Ecology, ISSN 1386-2588, Vol. 39, no 1, p. 41-53Article in journal (Refereed)
  • 5.
    Bjelke, Ulf
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Processing of two detritus types by lake-dwelling shredders: species-specific impacts and effects of species richness2005In: Journal of Animal Ecology, Vol. 74 (1), p. 92-98Article in journal (Refereed)
  • 6.
    Bohman, Irene
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The timing for winter-growing shredder species and leaf litter turnover rate in an oligotrophic lake, SE Sweden2006In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 556, no 1, p. 99-108Article in journal (Refereed)
    Abstract [en]

    Small freshwater systems often depend on allochthonous organic subsidies to sustain productivity. Benthic invertebrates consuming coarse detritus maintain the energy flow by conveying dead organic matter into prey items and increase the food availability for other consumers. Compared to lotic systems, the dynamics of coarse detritus decomposition has not received much attention in lakes. The objectives of this study were to investigate the seasonality of leaf litter turnover and the timing of abundance of potential shredder species in a typical oligotrophic boreal lake. Leaf litter was experimentally exposed in litterbags in the littoral zone in Lake Välen from autumn to late spring two consecutive years. The weight loss rate of leaf litter initially followed the same pattern during both winter periods, but was markedly influenced by freezing in late winter the second year. Further, the seasonal variation patterns in abundance in litterbags were quite different among the potential shredder species. Only the limnephilid caddis larvae showed a density variation pattern possible to connect to the weight loss of leaf litter in litterbags. Otherwise frequent detritivores such as Asellus aquaticus and Leptophlebia marginata displayed lowest density in litterbags during the main weight loss period. However, after the long ice period the second winter the remaining leaf litter seemed to be consumed by A. aquaticus. With increasing knowledge of the initial leaf breakdown process and the guild of shredders in lakes, the decomposition rate may also in this habitat become a useful instrument when evaluating the impact from perturbations on ecosystem function.

  • 7. Geijer, Bengt Olof
    et al.
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Intressanta fynd av vattenskalbaggar i Mittlandsskogen på Öland. [Interesting records of water-beetles in the Midland forest on Öland.]2005In: Entomologisk Tidskrift, ISSN 0013-886X, Vol. 126, no 3, p. 97-102Article in journal (Refereed)
  • 8.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Chemical and biological benefits in a stormwater wetland in Kalmar, SE Sweden2012In: Limnologica, ISSN 0075-9511, E-ISSN 1873-5851, Vol. 42, no 4, p. 299-309Article in journal (Refereed)
    Abstract [en]

    A manmade stormwater wetland in Kalmar, SE Sweden, sized 1 ha and receiving water from residential and road areas, was monitored over the first years after inundation with respect to chemistry and biology. Water flow and chemistry was analysed in years 2-4, mainly on a monthly basis, but, in the final year, every second month. This revealed that total nitrogen, according to the Swedish Environmental Quality Criteria (EQC), typically showed moderate or high concentrations, whereas total phosphorous levels were very high or extremely high. Metal (Cd, Cr, Cu, Pb and Zn) concentrations were low or moderate in terms of EQC. Yearly average reduction of nitrogen was 173 kg ha(-1) y(-1), tending to increase over time, and for phosphorous 12.1 kg ha(-1) y(-1), tending to decrease. Vegetation analysis was performed in years 1-4 by noting all species in 27 consecutive zones around the wetland system. This showed that one year after filling with water, the vegetation was already well established with >30 plant species in the entire pond system, and this increased only slightly. After four years, the shoreline vegetation cover had become denser, especially with larger graminoids such as common reed (Phragmites australis) and sea club-rush (Bolboschoenus maritimus), and submersed vegetation almost disappeared. There was a tendency for common species to become more dominant, and for less common species to become rarer. Using sweep net sampling of benthic invertebrates during years 0-2, ca 50 species/higher taxa were observed during the first year, largely because of the appearance of many beetles, especially dytiscids. However, these decreased the following years. Apart from these animals, in the first few months the invertebrate colonisation was dominated by chironomids and corixids, whereas later prominent increases were noticed for the isopod Asellus aquaticus, the snail Physa fontinalis, and the mayfly nymph Cloeon dipterum. The results are discussed in terms of wetland values for biodiversity and nutrient reduction, suggesting that these objectives seem possible to combine in stormwater wetlands.

  • 9.
    Herrmann, Jan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hagbygärde Dämme  – dagvattenbehandling i Kalmar; kemi och biologi 2012-20132014Report (Other academic)
    Abstract [sv]

    SAMMANFATTNING

    Hagbygärde Dämme, ett system med tre dammar (totalt ca 1.2 ha), var färdiggrävt i mars 2012. Delarna höll i vissa delar vatten under kommande halvåret, och mottog sedan slutet av oktober samma år dagvatten från ett 650 ha stort tillrinningsområde, som dräneras av Hagbygärdediket. Området ligger i västra delarna av Kalmar, och innehåller bostäder, köpcentra, lättare industrier, väg- och parkeringsområden, samt jordbruks- och skogspartier.

    Det primära syftet med Hagbygärde Dämme är att rena dikets kraftigt belastade dagvatten, Under perioden oktober 2012 till december 2013 togs vattenprover varannan vecka in i och ut från dämmet. Dessa analyserades m a p halter av totalkväve och totalfosfor, fraktioner av dessa, samt totalt suspenderade ämnen (TSS), åtta tungmetaller och olja. Vattenföring mättes fortlöpande automatiskt, men apparaturen gav inte tillförlitliga värden.

    Även den biologiska mångfalden i området kan förhoppningsvis gynnas. Bottenfaunan följdes från april 2012 till september 2013, dammarnas växter inventerades i huvudsak i sept/okt 2013 och fågelobservationer för 2012-2013 samlades in.

    För information av använda metoder, beräkningar och annan information med avseende på vattenföring, vatten- och sedimentkemi samt växter och djur, hänvisas till respektive inlednings- och metodavsnitt. Här följer de viktigare resultaten i punktform, för detaljer och tolkning, se respektive resultat- och diskussionsavsnitt. NV = Naturvårdsverkets (1999) bedömningsgrunder, ”Tillstånd” (bilaga 3). Sth = riktvärden för dagvatten som tagits fram i Stockholms län (2009), i kap 3 kallade ”Sth-riktvärden” (bilaga 3).

     

    KEMI

    • Tot-N varierade 1,6 – 9,0 mg/l IN och 1,0 – 10 mg/l UT, utloppet alltid lägre, halterna bedömda som mycket höga (flertalet) - extremt höga (NV), respektive höga (Sth).
    • Nitrat- + nitritkväve varierade 0,52 – 8,4 mg/l IN och 0,27 – 9,6 mg/l UT, utloppet oftast lägre. Ingen bedömningsgrund från NV eller Sth.
    • Ammoniumväve varierade 0,24 – 1,9 mg/l IN och 0,04 – 2,7 mg/l UT, utloppet oftast lägre. Ingen bedömningsgrund från NV eller Sth.
    • Tot-P varierade 0,03 – 0,16 mg/l IN och 0,02 – 0,18 mg/l UT, utloppet nästan alltid lägre, halterna bedömda som höga - mycket höga (flertalet) (NV), respektive ej höga (Sth).
    • Fosfatfosfor varierade 0,01 – 0,08 mg/l IN och 0,003 – 0,08 mg/l UT, utloppet nästan alltid lägre. Ingen bedömningsgrund från NV eller Sth.
    • Metall-koncentrationer: Kvicksilver, arsenik, kadmium och krom låg oftast under eller lika med respektive detektionsgräns, mindre ofta även bly. Halterna för de fyra första metallerna, samt nickel, bedöms som låga, för bly och zink måttligt höga, och för koppar måttligt höga till höga (NV). Alla metaller under Sth-riktvärdena.
    • TSS varierade 2,5 – 46 mg/l IN och 3,9 – 16 mg/l UT, utloppet nästan alltid lägre. Ingen bedömningsgrund från NV.
    • Reduktionen baserad på vattenföring kunde inte räknas ut, pga osäkra värden på densamma. Dock, differensen In–Ut för näringsämnen var signifikant för ammonium. Differensen In–Ut för metaller var signifikant för nickel, bly och zink.
    • Olja (fåtal mätningar) låg samtliga under Sth-riktvärdet för ”oljeindex”.
    • Sediment-metallerna (två mättillfällen) för As, Cd, Cr, Cu, Hg, Pb och Zn bedömdes som låga –mycket låga, medan för Ni bedömdes de som måttligt höga (NV).
    • pH (fåtal mätningar) varierade 7,0 – 7,3 dvs mycket god buffertkapacitet (NV).

     

    BIOLOGI

    • Vegetationen utvecklades måttligt under 2012-2013, delvis pga temporär torrläggning.
    • Antal växtarter i hela systemet var (efter ett år) ca 25, vilket är acceptabelt i så här i början.
    • Dominerande växtarter var svalting, veketåg, bladvass, vattenmöja, smalkaveldun, gäddnate.
    • Undervattensväxter ökade något mellan 2012 och 2013, vilket är bra, ty de gynnar dentrifikationen (N-reduktion).
    • Bottenfauna (evertebrater) koloniserade med ca 70 arter (eller högra taxa) under detta första 1,5 år, en hög siffra.
    • Vanligaste djur i början var skalbaggar, buksimmare, hinnkräftor och fjädermygglarver, samt i mindre grad dagsländan Cloeon dipterum, alla dessa typiska kolonisatörer för nya småvatten.

    Ett halvår efter start hade även gråsuggan Asellus aquaticus, dagsländan Caenis horaria och snäckan Physa fontinalis ökat.

  • 10.
    Herrmann, Jan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Skälby Dämme: en dagvatten-våtmark i Kalmar; kemi och biologi 2011 – 20122013Report (Other academic)
  • 11.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Skälby Dämme, en dagvatten-våtmark i Kalmar; kemi och biologi under de första åren2011Report (Other academic)
  • 12.
    Herrmann, Jan
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Bjelke, Ulf
    Cronberg, Gertrud
    Grenstadius, Mikael
    Olsson, Joakim
    Paulsson, Sara
    Rodebrand, Staffan
    Hornsjöns biologi 2004-20052006Report (Other academic)
    Abstract [sv]

    Det kan troligen sägas att en höjning av vattenståndet med ca 10 cm bör inte ha allvarligare konsekvenser för sjöns biologi. Möjligen kan erhållas viss positiv effekt; igenväxning kanske kan bromsas något, se avsnittet om Vegetation. Men det bör också framhållas att gäddans situation i sjön och dess vandringsmöjligheter och leksituation bör beaktas och utvecklas i samband med planerade åtgärder.

    Vissa av de biologiska parametrar som nu studerats i Hornsjön har förut gjorts studier av, nämligen vegetation (Wallsten 1979), plankton och bottenfauna (Berggren 1979), fåglar (Rodebrand 1979) samt fisk och plankton (Aspengren 1985, Troschke 1987). För dessa organismgrupper görs vissa jämförelser mellan 70-talet och 2004/2005, dvs oftast knappt 30 år. Vissa jämförelser har gjorts med nämnda publikationer. En mer omfattande analys avses göras i en planerad rapport om sjöns biologi. Där skall alla kända biologiska fakta sammanfattas och kommenteras.

  • 13.
    Herrmann, Jan
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Thorén, Ann-Karin
    Biologisk mångfald i Kalmar Dämme 1997-98 – kolonisation av växter, bottenfauna, fiskar och fåglar2003Report (Other academic)
    Abstract [sv]

    Flertalet konstgjorda våtmarker har anlagts med primärt syfte att kunna reducera näringsämnen, främst kvävets läckage till havet. I många fall finns även avsikten att skapa fler miljöer för akvatiska växter och djur, d.v.s. att gynna den lokala biologiska mångfalden ( ≈ antalet arter) i jordbruksbygderna, där oftast våtmarkerna starkt minskat de senaste två seklen. Anmärkningsvärt få uppföljningar genomförs, i synnerhet av de biologiska syftena.

    Goda skäl att gynna våtmarkers biologiska mångfald är dess betydelse för ekosystemets funktioner, att de är viktiga rekreationsområden och ansvaret för dessa ekosystems värden. Kalmar Dämme anlades primärt för reduktion av kväve från flygplatsen. Området var tidigare en havsvik som senaste decennierna använts som tämligen näringsrik odlings- och betesmark. Det 2.8 km långa systemet av avlånga dammar (djup ≤1.5 m), inklusive två gamla vassområden, koloniserades snabbt av växter och djur. Här rapporteras studier av vattenväxter, bottenfauna, fisk och fåglar i Kalmar Dämme under i huvudsak 1997-98.

    Växtstudierna (19 provpunkter för- och sensommar, flest 1998; båt, rut-analys för täckningsgrad, täthet, utbredning och växtdjup) syftade till att urskilja vilka växtsamhällen som fanns i/vid vattnet, inte en komplett artlista (flertalet är landlevande). Dominerande övervattenväxt var vass, men även kaveldun och svalting. Flertalet införda arter hade i huvudsak försvunnit, troligen p.g.a. erosion. Den för kvävereduktionen (och bottenfaunan) troligen viktigare undervattenvegetationen dominerades redan 1998 av vattenpest (inplanterad), efterhand ännu mer. I mindre omfattning påträffades ax- och kransslinga, vattenbläddra och kransalger. Vattenpestens dominans är möjligen av fördel, då den ger stor ytförstoring för de kvävereducerande bakterierna. Enbart 1997 sågs stora mängder av fintrådiga grönalger, möjligen beroende på de relativt låga fosforhalterna.

    Bottenfaunastudierna (sju prover på vardera fem grunda lokaler var 6-9:e vecka under drygt ett år; Surber eller standardhåv 0.5 mm maskvidd) avsåg att följa kolonisationsförloppet på de från början ”bara” bottenytorna. Artantalet ökar med tiden, i juni 1998 var ”ackumulerade” artantalet per lokal ca 40-50. Högst individantal noterades under försommaren, medan ”momentana” artantalen toppar sensommar/höst. Under första året (1997) dominerade fjädermygglarver och buksimmare. Bägge, men framför allt de senare, minskade nästföljande år. Då ökade istället en dagsländelarv och en snäcka, men även gråsuggor, samt vissa natt- och trollsländelarver. Den artrikaste gruppen var skalbaggar. Denna studie har fortsatt, om än med minskad intensitet.

    Fiskstudierna (ett examensarbete sommaren 1998, olika typer av nät under vardera 8-9 nätter/tillfällen, samt försök med håv och elfiske) syftade till att klarlägga vilka arter, och i vilka proportioner, som fanns i systemet. Mört och björkna dominerade, i övrigt fångades gädda, abborre, sutare och sarv. De tre första lyckades bra med reproduktionen, många 0+ och 1+ fångades. Beståndet av fisk är typiskt för näringsrika vatten.

    Fågelstudierna (ett examensarbete våren-sommaren 1997 samt två fritidsornitologers alla observationer under flera år; inga systematiskt upplagda inventeringar) avsåg att söka fastställa vilka arter, främst de ”vattenanknutna”, som med hur många par häckade i området. Under 1997 var dessa antal ca 35 respektive 13, med svag ökning på senare år. Totala antalet observerade arter har de flesta år varit ca 150, varav många bara rastande eller överflygande. T.o.m. år 2001 har totalt sett 201 fågelarter noterats. Notabla häckande arter är/har varit smådopping, vigg, brun kärrhök, vattenrall, mindre strandpipare, skäggmes och pungmes. ”Intressanta” observationer är främst rördrom, snatterand, fiskgjuse och rosenfink.

    De biologiska resultaten utgör en viktig grund för övrig våtmarksinriktad FoU-verksamhet i Kalmar, liksom kommunens skötsel av Kalmar Dämme och andra rekreationsområden med våtmarker inklusive information om dylika områdens värden. Dessutom behövs bättre vetenskapliga kunskaper om kolonisationsförlopp av växter och djur i våtmarksområden.

  • 14.
    Herrmann, Jan
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Yoshiyama, Miku
    Treating urban stormwater in constructed wetlands in Kalmar, SE Sweden, for improved water quality and biodiversity2014In: Proc. 9th Int. Conf. on the Establishment of Cooperation between Companies and Institutions in the Nordic Countries, the Baltic Sea Region and the World, 2014, p. 1-6Conference paper (Other academic)
    Abstract [en]

    Stormwaters’ heavy loads of nutrients, metals and oil etc, via urban ditches / streams, are increasingly treated in engineered shallow wetlands/ponds. Such approaches are still only remedying a minor part of affected storm waters, urban streams, and freshwater and marine recipients. In Kalmar, a middle-sized Swedish town at the Baltic Sea, > 10 such wetlands / ponds are established for reduction of such heavily polluted waters. Aiming at determining the effectiveness in reduction of nutrients and metals, and the facilitation of the aquatic biodiversity (primarily in the wetlands), monitoring programs were initiated. Regular in/outflow water sampling, water flow and biology, were followed for 1-2-3 years (varied with parameter) after construction in two of these wetlands. Skälby Dämme, constructed 14 years ago (2000), showed ca 40 % nutrient reduction figures, less for TSS and metals, while Hagbygärde Dämme, constructed two years ago (2012), attained only much lower results. Reasons for this difference might be that Hagbygärde is less surrounded by forested land, also that less than one year had elapsed before evaluation commenced, while two-three years in Skälby. More recent monitoring in Skälby Dämme is also compared with. Moreover, this kind of wetlands/ponds is shown to favour the biodiversity of benthic invertebrates, (aquatic) plants and birds, although with trends to decline in species richness some years after the initial colonization period.

  • 15.
    Leberfinger, Karolina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bohman, Irene
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Drought impact on stream detritivores - experimental effects on leaf litter breakdown and life cycles2010In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 652, no 1, p. 247-254Article in journal (Refereed)
    Abstract [en]

    Predictions of effects of global climate change include decreased runoff for many parts of the world, which will result in drying of streams. Information of the effects of drought on aquatic ecosystems is limited and little is known of the effects on ecosystem functions. Our main objective was to measure the direct effects of drought on leaf litter breakdown by invertebrate shredders in a controlled laboratory experiment. We hypothesized a decreased breakdown at high drought level. Single-species and multi-species treatments with three shredder species (Asellus aquaticus, Limnephilus bipunctatus, and L. flavicornis) were set up in an experiment with three drought level treatments, control, medium, and high drought (6 cm water level, 1 cm water level, and water level below sediment surface, respectively). Breakdown measured as leaf litter loss was significantly lower in both medium and high drought treatments compared to the control. Previously, decreased breakdown due to drying has been reported, but attributed to low densities of invertebrate shredders. We show that even when shredders are present, drought decreases the breakdown. Drought treatments also induced earlier pupation for the caddisfly L. flavicornis. Shifts in species phenology due to drought, e.g., earlier emergence, may affect species ability to adult survival and reproduction. Shifts in timing of emergence may also affect terrestrial food webs, where emerging aquatic insects may constitute an important food subsidy. Our knowledge of the complex effects of droughts in aquatic systems is limited with an urgent need of extended knowledge of the ecological effects of droughts on freshwater ecosystem functioning.

  • 16.
    Leberfinger, Karolina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Bohman, Irene
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    The importance of terrestrial resource subsidies for shredders in open-canopy streams revealed by stable isotope analysis2011In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 56, no 3, p. 470-480Article in journal (Refereed)
    Abstract [en]

    1. Allochthonous detritus is the major source of energy in forested streams, but less is known of the importance of terrestrial subsidies to open-canopy streams. Here, we used stable isotope analysis to assess the importance of allochthonous versus autochthonous energy sources to invertebrate shredders in four open-canopy streams in Sweden. Shredders and potential food sources were analysed at both open sites and those with deciduous trees in the riparian zone.2. Mixing models showed that allochthonous coarse particulate organic matter was the most important energy source to shredders at both the open and wooded sites, suggesting that terrestrial subsidies may be an important process in open-canopy streams, just as they are in forested streams.3. However, shredders at open sites had a larger proportion of biofilm in their diet than at wooded sites, indicating an ability of shredders to adjust their diet with food availability.4. We also used the carbon and nitrogen stable isotope signatures to assess the size of the feeding niche of shredders. Feeding on both allochthonous and autochthonous sources at open sites was reflected in a larger feeding niche than at wooded sites for one of the three species analysed. There was substantial overlap of the feeding niche among shredder species, indicating a high functional redundancy within this guild.

  • 17.
    Leberfinger, Karolina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Secondary production of invertebrate shredders in open-canopy, intermittent streams on the island of Öland, SE Sweden2010In: Journal of The North American Benthological Society, ISSN 0887-3593, E-ISSN 1937-237X, Vol. 29, p. 934-944Article in journal (Refereed)
    Abstract [en]

    Knowledge of functional aspects of communities in intermittent streams currently is lacking, and the role of terrestrial detritus as a resource in open-canopy streams is uncertain. Our main objective was to characterize and quantify the macroinvertebrate shredder assemblages in 3 intermittent open-canopy streams on the island of Öland in the Baltic Sea, Sweden, by estimating secondary production. Estimates of annual shredder secondary production ranged from 0.005 to 13.6 g ash-free dry mass (AFDM) m−2 y−1 among sites. Shredder production and amount of organic matter were positively related, but shredder production was more strongly influenced by the duration of the summer dry period. Production decreased with increase in the length of the summer dry period, but shredder production was still high at sites with long dry phases and was comparable to estimates of shredder production in permanent forested streams, results suggesting that terrestrial organic matter might be an important energy resource in open-canopy streams. Shredder species richness decreased with increase in length of the summer dry phase, and shredder species composition at sites with a long dry period was dominated by drought-tolerant taxa. Our results suggest that ecosystem functions might shift from being sustained by many taxa to being sustained by fewer taxa as stream ecosystems experience moderate droughts of similar length (2–4 mo).

  • 18.
    Leberfinger, Karolina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Spatial and temporal distribution of shredders in leaf-limited intermittent streams2010In: Verhandlungen Internat. Verein. Limnol 30, Stuttgart: E. Schweizerbart'sche Verlagsbuchhandlung, 2010, p. 1342-1344Conference paper (Refereed)
  • 19.
    Leberfinger, Karolina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hoover, Trent M.
    University of British Columbia.
    Bohman, Irene
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Richardson, John S.
    University of British Columbia.
    Modelling climatic change effects of decomposition processes in small streamsManuscript (preprint) (Other academic)
  • 20.
    Lindstroem, Marianne
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Johansson, Maria
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Jonsson, Olle
    Attitudes towards the Conservation of Biological Diversity - a Case Study in Kristianstad Municipality, Sweden2006In: Journal of Environmental Planning and Management, Vol. 49, no 4, p. 495-513Article in journal (Refereed)
    Abstract [en]

    Human actions towards land, freshwater and oceans have already caused biodiversity to decline. This study aims to investigate attitudes towards the conservation of biological biodiversity among different groups in a Swedish city, Kristianstad. An inquiry including statements measuring attitudes towards the conservation of habitats, animals and plants, to the biological diversity within selected local areas, to global and national areas, and to societal issues, was replied to by 271 persons. Deciduous forests, birds and wild flowers were given highest priority. An area categorized as wetland including lakeshore meadows with a rich bird life was prioritized as most important for conservation while a forest area was chosen as best for recreation. The experts gave lower priority to arable land, urban parks, domestic animals, agricultural and garden plants and to conifer forests compared to the other groups. Knowledge about what people in general value as important could facilitate the future planning of nature areas in the city of Kristianstad. 

  • 21. Nordqvist, J
    et al.
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Vattenkvalster (Acari:Hydrachnidia) på Öland - vanliga men okända. [Water Mites (Acari:Hydrachnidia) on Öland – common but unknown.]2008In: Entomologisk Tidskrift, ISSN 0013-886X, Vol. 129, p. 1-7Article in journal (Refereed)
  • 22. Ruhi, Albert
    et al.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Gascon, Stephanie
    Sala, Jordi
    Geijer, Joja
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Boix, Daniel
    Change in biological traits and community structure of macroinvertebrates through primary succession in a man-made Swedish wetland2012In: Freshwater Science, ISSN 2161-9565, Vol. 31, no 1, p. 22-37Article in journal (Refereed)
    Abstract [en]

    We investigated the successional development of a benthic macrofaunal community in Kalmar Dämme, a man-made wetland in southeastern Sweden, over a 13-y period after construction (1997–2009). We assessed primary succession by monitoring changes in species composition, biological traits, and community structure. Predictable successional changes occurred, and the structure of the community was complex at the advanced phase. Three successional phases were observed, each with typifying species. At the advanced phase, dominant biological traits shifted to favor animals with longer life-cycle durations, aerial dispersal strategies, and certain feeding types (i.e., filter-feeders, fine sediment collectors, predators, and parasites). We selected the Coleoptera assemblage to represent the macroinvertebrate community in an evaluation of the extent to which man-made wetlands in different age classes (<3 y and ≥10 y) were similar to natural wetlands (>50 y). No significant differences in Coleoptera assemblages were found between natural wetlands and man-made wetlands ≥10 y. However, man-made wetlands ≥10 y had significantly higher coleopteran species richness than natural and man-made wetlands <3 y because of the convergence of pioneering species persisting from early successional stages with representative specialized taxa from natural wetlands. Our results suggest that 10 y may be sufficient time for the macrofaunal communities of man-made wetlands to resemble those of natural wetlands.

  • 23.
    Ruhi, Albert Vidal
    et al.
    Institute of Aquatic Ecology, University of Girona, Girona, Catalonia, Spain.
    Herrmann, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Gascon, Stephanie
    Institute of Aquatic Ecology, University of Girona, Girona, Catalonia, Spain.
    Sala, Jordi
    Institute of Aquatic Ecology, University of Girona, Girona, Catalonia, Spain.
    Boix, Daniel
    Institute of Aquatic Ecology, University of Girona, Girona, Catalonia, Spain.
    How do early successional patterns in man-made wetlands differ between cold temperate and Mediterranean regions?2012In: Limnologica, ISSN 0075-9511, E-ISSN 1873-5851, Vol. 42, no 4, p. 328-339Article in journal (Refereed)
    Abstract [en]

    The early stages of succession in newly created wetlands should be impacted by the region in which the wetland is located, since climate may have filtered the dominant biological strategies of the taxa leading this process and may condition their dynamics. We studied the early successional patterns of macroinvertebrates within man made ponds, located in cold temperate (Scandinavian Peninsula) and Mediterranean regions (Iberian Peninsula), during the first three years following their creation. We predicted (1) non random subsets of the regional species pool (deterministic assembly) guiding the successional process in cold temperate wetlands, and random (stochastic) assembly in the Mediterranean region; (2) higher successional rates in Mediterranean ponds than in the cold temperate ponds, with contrary episodes of highest and lowest change throughout the year; and (3) a significant difference in the composition of biological traits between regions, due to the dominance of traits adapted to hydrological variability in the Mediterranean region. Hypotheses on community structure (1) and the composition of dominant biological traits (3) were mostly supported - deterministic assembly mechanisms in the cold temperate ponds and stochastic assembly in the Mediterranean ponds; and a dominance of different biological traits between regions, explained by the need to overcome hydrological disturbances in the Mediterranean ponds. The dynamics of succession (2) were explained by climatic factors in the cold temperate region but not in the Mediterranean ponds. We suggest that the intrinsic hydrological variability of Mediterranean lentic systems may be a major factor driving community changes in man-made wetlands in this region. In order to generalize the observed patterns, we performed a meta-analysis of the temporal trends of taxonomic distinctness parameters of other successional studies across a latitudinal gradient in Europe, which supported the differences we had observed between latitudinal extremes.

  • 24.
    Smith, Robert
    et al.
    Massachusetts Cooperative Fish and Wildlife Research Unit, USA.
    Hawley, Robert
    Sustainable Streams, USA.
    Neale, Martin
    Golder and Associates, New Zealand.
    Vietz, Geoff
    University of Melbourne, Australia.
    Ciaz-Pascacio, Erika
    El Colegio Frontera Sur, Mexico.
    Herrmann, Jan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Lovell, Anthony
    University of Melbourne, Australia.
    Precott, Chris
    City of Portland, USA.
    Rios-Touma, Blanca
    Universidad Tecnológica Indoamérica, Ecuador.
    Smith, Benjamin
    King’s College London, UK.
    Utz, Ryan
    Chatham University, USA.
    Urban stream renovation: incorporating societal objectives to achive ecological improvements2016In: Freshwater Science, ISSN 2161-9549, E-ISSN 2161-9565, Vol. 35, no 1, p. 364-379Article in journal (Refereed)
    Abstract [en]

    Pervasive human impacts on urban streams make restoration to predisturbance conditions unlikely. The effective- ness of ecologically focused restoration approaches typically is limited in urban settings because of the use of a reference-condition approach, mismatches between the temporal and spatial scales of impacts and restoration activities, and lack of an integrative ap- proach that incorporates ecological and societal objectives. Developers of new frameworks are recognizing the opportunities for and benefits from incorporating societal outcomes into urban stream restoration projects. Social, economic, cultural, or other benefits to local communities are often opportunistic or arise indirectly from actions intended to achieve ecological outcomes. We propose urban stream renovation as a flexible stream improvement framework in which short-term ecological and societal outcomes are leveraged to achieve long-term ecological objectives. The framework is designed to provide additional opportunities for beneficial outcomes that are often unattainable from ecologically focused restoration approaches. Urban stream renovation uses an iterative process whereby short-term ecological and societal outcomes generate public support for future actions, which may provide opportunities to address catchment-level causes of impairment that often exist across broad temporal scales. Adaptive management, education, and outreach are needed to maintain long-term public engagement. Thus, future work should focus on understanding how ecological and societal contexts interact, how to assess societal outcomes to maintain stewardship, developing new methods for effective education and outreach, and multidisciplinary collaborations. We discuss potential abuses and the im- portance of linking societal outcomes to long-term ecological objectives. 

  • 25.
    Stenroth, Karolina
    et al.
    Umeå universitet.
    Hoover, Trent M.
    University of British Columbia, Vancouver, BC, Canada.
    Herrmann, Jan
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bohman, Irene
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Richardson, John S.
    University of British Columbia, Vancouver, BC, Canada.
    A model-based comparison of organic matter dynamics in forested and open-canopy streams2014In: Riparian Ecology and Conservation, ISSN 2299-1042, Vol. 2, no 1Article in journal (Refereed)
    Abstract [en]

    The food webs of forest streams are primarily based upon inputs of organic matter from adjacent terrestrial ecosystems. However, streams that run through open landscapes generally lack closed riparian canopies, and an increasing number of studies indicate that terrestrial organic matter may be an important resource in these systems as well. Combining key abiotically-controlled factors (stream discharge, water temperature, and litter input rate) with relevant biotic processes (e.g. macroinvertebrate CPOM consumption, microbial processing), we constructed a model to predict and contrast organic matter dynamics (including temporal variation in CPOM standing crop, CPOM processing rate, FPOM production, and detritivore biomass) in small riparian-forested and open-canopy streams. Our modeled results showed that the standing crop of CPOM was similar between riparian-forested and open-canopy streams, despite considerable differences in litter input rate. This unexpected result was partly due to linkages between CPOM supply and consumer abundance that produced higher detritivore biomass in the forest stream than the open-canopy stream. CPOM standing crop in the forest stream was mainly regulated by top-down consumer control, depressing it to a level similar to that of the open-canopy stream. In contrast, CPOM standing crop in the open-canopy stream was primarily controlled by physical factors (litter input rates and discharge), not consumption. This suggests that abiotic processes (e.g. discharge) may play a greater role in limiting detrital resource availability and consumer biomass in open-canopy streams than in forest streams. These model results give insight on functional differences that exists among streams and they can be used to predict effects of anthropogenic influences such as forestry, agriculture, urbanization, and climate change on streams and how riparian management and conservation tools can be employed to mitigate undesirable effects.

  • 26. Thorén, AK
    et al.
    Legrand, Catherine
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Transport and transformation of de-icing urea from airport runways in a constructed wetland system2003In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Water Science and Technology, Vol. 48, no 5, p. 283-290Article in journal (Refereed)
    Abstract [en]

    Urea, NH2-CO-NH2, is used as a de-icing agent at Kalmar Airport, southeast Sweden. During 1998-2001, urea contributed on average 30% of the yearly nitrogen (N) transport of 41,000 kg via Tornebybacken stream to the coastal zone of the Baltic Sea. In order to reduce stream transport of N from airport, agricultural and other diffuse sources, a wetland was constructed in 1996. Annual wetland retention of total-N varied in the range of 2,500-8,1100 kg (6-36% of influent) during 1998-2001, according to mass balances calculated from monthly sampling. During airport de-icing, January-March 2001, 660 kg urea-N out of 2,600 kg applied urea-N reached the wetland according to daily sampling. This indicated that 75% of the urea was transformed before entering the wetland. Urea was found to be only a minor part (8%) of total-N in the wetland influent. Calculations of cumulative urea-N loads at the wetland inlet and outlet respectively, showed a significant urea. transformation during February 2001 with approximately 40% of the incoming urea-N being transformed in the wetland system. These results show that significant amounts of urea can be transformed in a wetland system at air temperatures around 0degreesC. 

  • 27. Tonderski, K.S.
    et al.
    Svensson, J.M.
    Ekstam, Börje
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Eriksson, P.
    Fleischer, S.
    Herrmann, Jan
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Sahlén, G.
    Weisner, S.E.B.
    Våtmarker - närsaltsfällor och/eller myllrande mångfald?2003In: Vatten - tidskrift för vattenvård, ISSN 0042-2886, Vol. 59, no 4, p. 259-270Article in journal (Other academic)
1 - 27 of 27
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