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Herrmann, Jan
Publications (10 of 27) Show all publications
Smith, R., Hawley, R., Neale, M., Vietz, G., Ciaz-Pascacio, E., Herrmann, J., . . . Utz, R. (2016). Urban stream renovation: incorporating societal objectives to achive ecological improvements. Freshwater Science, 35(1), 364-379
Open this publication in new window or tab >>Urban stream renovation: incorporating societal objectives to achive ecological improvements
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2016 (English)In: Freshwater Science, ISSN 2161-9549, E-ISSN 2161-9565, Vol. 35, no 1, p. 364-379Article in journal (Refereed) Published
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. 

Keywords
stream restoration, urbanization, ecological, societal, adaptive management, stewardship, environmental education
National Category
Ecology
Research subject
Ecology, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-50270 (URN)10.1086/685096 (DOI)000370993800029 ()2-s2.0-84960874865 (Scopus ID)
External cooperation:
Available from: 2016-03-06 Created: 2016-03-06 Last updated: 2017-11-30Bibliographically approved
Stenroth, K., Hoover, T. M., Herrmann, J., Bohman, I. & Richardson, J. S. (2014). A model-based comparison of organic matter dynamics in forested and open-canopy streams. Riparian Ecology and Conservation, 2(1)
Open this publication in new window or tab >>A model-based comparison of organic matter dynamics in forested and open-canopy streams
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2014 (English)In: Riparian Ecology and Conservation, ISSN 2299-1042, Vol. 2, no 1Article in journal (Refereed) Published
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.

National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-32983 (URN)10.2478/remc-2014-0001 (DOI)
Available from: 2014-03-18 Created: 2014-03-18 Last updated: 2014-12-12Bibliographically approved
Herrmann, J. (2014). Hagbygärde Dämme  – dagvattenbehandling i Kalmar; kemi och biologi 2012-2013. Kalmar: Linnéuniversitetet
Open this publication in new window or tab >>Hagbygärde Dämme  – dagvattenbehandling i Kalmar; kemi och biologi 2012-2013
2014 (Swedish)Report (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.

Place, publisher, year, edition, pages
Kalmar: Linnéuniversitetet, 2014. p. 58
Series
Rapport från Linnéuniversitetet, Inst f Biologi och Miljövetenskap ; 2014:7
National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-38770 (URN)
Available from: 2014-12-27 Created: 2014-12-27 Last updated: 2015-01-13Bibliographically approved
Herrmann, J. & Yoshiyama, M. (2014). Treating urban stormwater in constructed wetlands in Kalmar, SE Sweden, for improved water quality and biodiversity. In: Proc. 9th Int. Conf. on the Establishment of Cooperation between Companies and Institutions in the Nordic Countries, the Baltic Sea Region and the World: . Paper presented at Linnaeus Eco-Tech 2014, November 24-26, 2014, (pp. 1-6).
Open this publication in new window or tab >>Treating urban stormwater in constructed wetlands in Kalmar, SE Sweden, for improved water quality and biodiversity
2014 (English)In: 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, Published 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.

National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-38767 (URN)
Conference
Linnaeus Eco-Tech 2014, November 24-26, 2014,
Available from: 2014-12-27 Created: 2014-12-27 Last updated: 2015-01-13Bibliographically approved
Herrmann, J. (2013). Skälby Dämme: en dagvatten-våtmark i Kalmar; kemi och biologi 2011 – 2012. Kalmar: Linnéuniversitetet
Open this publication in new window or tab >>Skälby Dämme: en dagvatten-våtmark i Kalmar; kemi och biologi 2011 – 2012
2013 (Swedish)Report (Other academic)
Place, publisher, year, edition, pages
Kalmar: Linnéuniversitetet, 2013. p. 58
Series
Rapport/Institutionen för biologi och miljövetenskap ; 2013:7
National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-32984 (URN)
Available from: 2014-03-18 Created: 2014-03-18 Last updated: 2015-01-13Bibliographically approved
Ruhi, A., Herrmann, J., Gascon, S., Sala, J., Geijer, J. & Boix, D. (2012). Change in biological traits and community structure of macroinvertebrates through primary succession in a man-made Swedish wetland. Freshwater Science, 31(1), 22-37
Open this publication in new window or tab >>Change in biological traits and community structure of macroinvertebrates through primary succession in a man-made Swedish wetland
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2012 (English)In: Freshwater Science, ISSN 2161-9565, Vol. 31, no 1, p. 22-37Article in journal (Refereed) Published
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.

National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-16407 (URN)10.1899/11-018.1 (DOI)2-s2.0-84860595525 (Scopus ID)
Projects
Jan Herrmann
Available from: 2011-12-28 Created: 2011-12-28 Last updated: 2012-12-05Bibliographically approved
Herrmann, J. (2012). Chemical and biological benefits in a stormwater wetland in Kalmar, SE Sweden. Limnologica, 42(4), 299-309
Open this publication in new window or tab >>Chemical and biological benefits in a stormwater wetland in Kalmar, SE Sweden
2012 (English)In: Limnologica, ISSN 0075-9511, E-ISSN 1873-5851, Vol. 42, no 4, p. 299-309Article in journal (Refereed) Published
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.

National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-16408 (URN)10.1016/j.limno.2012.07.003 (DOI)2-s2.0-84867462132 (Scopus ID)
Projects
Jan Herrmann
Available from: 2011-12-28 Created: 2011-12-28 Last updated: 2017-12-08Bibliographically approved
Ruhi, A. V., Herrmann, J., Gascon, S., Sala, J. & Boix, D. (2012). How do early successional patterns in man-made wetlands differ between cold temperate and Mediterranean regions?. Limnologica, 42(4), 328-339
Open this publication in new window or tab >>How do early successional patterns in man-made wetlands differ between cold temperate and Mediterranean regions?
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2012 (English)In: Limnologica, ISSN 0075-9511, E-ISSN 1873-5851, Vol. 42, no 4, p. 328-339Article in journal (Refereed) Published
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.

Keywords
Aquatic macroinvertebrates, Biological traits, Climatic regions, Colonization, Man-made wetlands, Taxonomic distinctness, aquatic organism, climatic region, cold region, community structure, macroinvertebrate, pond, pool, succession, taxonomy, temperate environment, wetland, Iberian Peninsula, Mediterranean Region, Scandinavia
National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-16406 (URN)10.1016/j.limno.2012.07.005 (DOI)2-s2.0-84867465476 (Scopus ID)
Projects
Jan Herrmann
Available from: 2011-12-28 Created: 2011-12-28 Last updated: 2017-12-08Bibliographically approved
Bergsten, J., Bilton, D. T., Fujisawa, T., Elliott, M., Monaghan, M. T., Balke, M., . . . Vogler, A. P. (2012). The Effect of Geographical Scale of Sampling on DNA Barcoding. Systematic Biology, 61(5), 851-869
Open this publication in new window or tab >>The Effect of Geographical Scale of Sampling on DNA Barcoding
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2012 (English)In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 61, no 5, p. 851-869Article in journal (Refereed) Published
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.

Keywords
Agabini, diving beetles, DNA barcoding, Dytiscidae, iBOL, identification methods, sampling, scale effect, species monophyly
National Category
Zoology
Research subject
Ecology, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-22298 (URN)10.1093/sysbio/sys037 (DOI)000307524200012 ()2-s2.0-84865230044 (Scopus ID)
Available from: 2012-11-06 Created: 2012-11-06 Last updated: 2017-12-07Bibliographically approved
Aura, C., Raburu, P. & Herrmann, J. (2011). Macroinvertebrates’ community structure in Rivers Kipkaren and Sosiani, River Nzoia basin, Kenya. Journal of Ecology and the Natural Environment, 3(2), 39-46
Open this publication in new window or tab >>Macroinvertebrates’ community structure in Rivers Kipkaren and Sosiani, River Nzoia basin, Kenya
2011 (English)In: Journal of Ecology and the Natural Environment, ISSN 2006-9847, E-ISSN 2006-9847, Vol. 3, no 2, p. 39-46Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Academic Journals, 2011
National Category
Ecology
Research subject
Natural Science, Aquatic Ecology
Identifiers
urn:nbn:se:lnu:diva-10872 (URN)
Available from: 2011-02-19 Created: 2011-02-19 Last updated: 2017-12-11Bibliographically approved
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