47 research outputs found
Yield-biodiversity trade-off in patchy fields of Miscanthus Ă giganteus
Increasing crop productivity to meet rising demands for food and energy, but doing so in an environmentally sustainable manner, is one of the greatest challenges for agriculture to date. In Ireland, Miscanthus 9 giganteus has the potential to become a major feedstock for bioenergy production, but the economic feasibility of its cultivation depends on high yields. Miscanthus fields can have a large number of gaps in crop cover, adversely impacting yield and hence economic viability. Predominantly positive effects of Miscanthus on biodiversity reported from previous research might be attributable to high crop patchiness, particularly during the establishment phase. The aim of this research was to assess crop patchiness on a field scale and to analyse the relationship between Miscanthus yield and species richness and abundance of selected taxa of farmland wildlife. For 14 Miscanthus fields at the end of their establishment phase (4â5 years after planting), which had been planted either on improved grassland (MG) or tilled arable land (MT), we determined patchiness of the crop cover, percentage light penetration (LP) to the lower canopy, Miscanthus shoot density and height, vascular plants and epigeic arthropods. Plant species richness and noncrop vegetation cover in Miscanthus fields increased with increasing patchiness, due to higher levels of LP to the lower canopy. The species richness of ground beetles and the activity density of spiders followed the increase in vegetation cover. Plant species richness and activity density of spiders on both MT and MG fields, as well as vegetation cover and activity density of ground beetles on MG fields, were negatively associated with Miscanthus yield. In conclusion, positive effects of Miscanthus on biodiversity can diminish with increasing productivity. This matter needs to be considered when assessing the relative ecological impacts of developing biomass crops in comparison with other land use. Keywords: Araneae, Carabidae, crop cover, light penetration, Miscanthus establishment, patchiness, vascular plants, vegetation coverYield-biodiversity trade-off in patchy fields of Miscanthus Ă giganteuspublishedVersio
Pratar vi mobbning eller? - AnstÀlldas syn pÄ begreppen mobbning och krÀnkande sÀrbehandling samt pÄ hur psykosociala missförhÄllanden pÄ arbetsplatsen bör förebyggas
Denna studie hade tvÄ syften. Det första syftet var att undersöka hur anstÀllda i Göteborgs Stad tolkar och relaterar till begreppen mobbning och krÀnkande sÀrbehandling. Det andra syftet var att undersöka vad anstÀllda har för faktiska erfarenheter av förebyggande arbete mot mobbning/krÀnkande sÀrbehandling och hur de skulle önska att detta arbete bedrevs.
I denna studie har vi i första hand utgÄtt ifrÄn Leymann (1990) och Einarsens (2000) begreppsdefinitioner och rön gÀllande förebyggande arbete vad det gÀller missförhÄllanden i den psykosociala arbetsmiljön.
Vi genomförde semistrukturerade intervjuer med tolv anstÀllda inom vÄrdsektorn i Göteborgs Stad. Intervjuerna innehöll öppna frÄgor kring begreppsdefinitioner och förebyggande arbete. Intervjumaterialet analyserade via tematisk analys. TvÄ tematiska analyser gjordes, en för vart och ett av studiens syften.
Den första analysen hade fokus pĂ„ begreppsdefinitioner och vi fann dĂ€r tre teman som sammanfattade de anstĂ€lldas tankar kring de undersökta begreppen: a) Mobbning i skolan â krĂ€nkande sĂ€rbehandling pĂ„ arbetsplatsen, b) Subjektiv upplevelse eller avsiktlig handling? och c) Konflikt pĂ„ gott och ont. Inga av de begrepp som vi har undersökt - mobbning och krĂ€nkande sĂ€rbehandling - upplevdes av respondenterna som ideala för att fĂ„nga alla nyanser av psykosociala missförhĂ„llanden pĂ„ arbetsplatsen. Mobbningsbegreppet visade sig vara alltför fĂ€rgat av det som förekommer inom skolans vĂ€rld. KrĂ€nkande sĂ€rbehandling upplevdes alltför kontextlöst.
Den andra tematiska analysen fokuserade pĂ„ respondenternas förslag pĂ„ hur man bör bedriva det förebyggande arbetet mot mobbing. HĂ€r fann vi sex teman: a) Aktivt deltagande i utformandet av policydokument, b) NĂ€rvarande och lyhörda chefer, c) Skapa ett öppet arbetsklimat, d) Hitta forum för att diskutera mobbning/krĂ€nkande sĂ€rbehandling, e) Skapa tydliga rollfördelningar och f) HRs roll â för vem? VĂ„ra resultat visar pĂ„ flera möjliga alternativ till att arbeta förebyggande för att förbĂ€ttra den psykosociala arbetsmiljön. Med tanke pĂ„ de enorma kostnader som drabbar organisationer om de inte lyckas motverka psykosociala missförhĂ„llanden Ă€r det viktigt att dessa frĂ„gor inte hamnar i bakgrunden utan fĂ„r ta den plats de behöver
Videoinstruktioner till bildundervisningen med tema sjÀlvportrÀtt i olika tekniker
I denna studie ligger fokus pÄ utformning av videoinstruktioner i bildÀmnet pÄ gymnasieskolan vilka utvÀrderats via intervjuer av olika informanter, lÀrare och studenter. De videoinstruktionerna som utformades under arbetet bearbetades efter bland annat motivationsteorier, didaktik i bildklassrummet och innefattar konkreta material samt tekniska instruktioner. Uppgifterna har producerats med sjÀlvportrÀtt som det sammanhÀngande temat, i de olika tekniker som tas upp under Àmnet bild. Enligt lÀroplanen skall eleverna bland annat med hjÀlp av olika tekniker och uttryckssÀtt genom bÄde traditionella metoder samt nyare konstformer, fÄ en bÀttre förmÄga att sjÀlva utforma konstbilder och konstföremÄl med olika uttryck och budskap. Teknikerna sammanstÀlldes till instruktionsfilmer som kan anvÀndas som ett stöd till lektioner i bild. Videoinstruktionerna hade Àven som mÄl att motivera eleverna, samt att möta elevers varierande instÀllning och arbetssÀtt oberoende vilken motivationsgrad de har i Àmnet. En intervju genomfördes med en lÀrare efter att ha visat videoinstruktionerna. En gruppintervju genomfördes med lÀrarstudenter, detta för att inhÀmta deras Äsikter om videoinstruktionen som lÀromedel. Centrala teman som framfördes av informanterna under intervjuerna var bland annat att videoinstruktionen har flera fördelar i en skolmiljö. Det sparar tid och Àr ett inlÀgg i elevernas IT kultur som de lÀtt kan relatera till. Videoinstruktionen Àr motiverande för eleverna men har begrÀnsningar. Instruktionens budskap mÄste slipas noga för att komma fram i den form som lÀraren avser. Den bör Àven anvÀndas i kombination med annan undervisning för bÀsta resultat
Local resources, linear elements and mass-flowering crops determine bumblebee occurrences in moderately intensified farmlands
There is consensus that land-use change is a main driver behind the recent declines of many pollinator
populations in Europe. However, it is still not adequately understood how the local resource quality and
landscape composition influence pollinators, and if and how the effects vary in space and time. We
analysed the influence of landscape- (2 km radius) and local scale- (50 m transects) resources on
bumblebee species richness and abundance during two years in South-eastern Norway, where
agriculture is highly modernised but landscapes still show limited spatial homogenization. Local
flower
density and species richness were strongly positively associated with bumblebee densities and species
richness, but higher landscape-level
flower species richness were linked to lower local bumblebee
abundances. Early and late mass
flowering crops had clear, but contrasting, effects. The total area of early
flowering crops had a consistent negative impact on bumblebee density and species richness throughout
the season, while late
flowering crops had a positive impact in the beginning of the season before their
bloom, suggesting a carry-over effect from previous years. The negative effects of early
flowering crops
could be due to competition of bumblebees with honey-bees, which are widely used in these crops.
Bumblebee density and species richness were clearly negatively correlated with the total area of forest
and
flower-poor land use areas, including grass
fields and cereals. In contrast, bumblebees were
positively associated with most linear elements in the landscape (especially pasture and cropland
verges), except for roads, which negatively affected bumblebee densities, possibly due to increased
mortality, since the quality of the
flower resources did not differ from other linear elements. Our results
show that the quality and the spatial and temporal distribution of
flower resources within the landscape
are important drivers for bumblebees, but can create counterintuitive distribution patterns depending on
the temporal and spatial resolution of the survey. Increasing
flower resources in linear elements and the
amount of late mass-flowering crops may be viable management measures to improve conditions for
bumblebees in moderately intensified landscapes.
© 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Assessing Norwegian pollination deficits. Capacity building towards IPBES - implementation and methodological evaluation of the âProtocol to Detect and Assess Pollination Deficits in crops.
Ă
ström, J., Dramstad, W., Debella-Gilo, M., Hovstad, K. A., Ă
ström, S. & Rusch, G. M. 2014.
Assessing Norwegian pollination deficits. Capacity building towards IPBES, with implementation
and methodological evaluation of the âProtocol to Detect and Assess Pollination Deficits in
cropsâ. - NINA Report 1101. 51 pp.
In 2012, the Norwegian Environmental Agency funded an extension to the Global Pollination
Project, coordinated by the FAO (Food and Agriculture Organization of the United Nations) to
expand the number of connected countries from 7 fully participating to in total 13 countries.
This international effort seeks to build capacity for pollination studies and add to the knowledge
base for the Intergovernmental Platform for Biodiversity and Ecosystem Services (IPBES).
IPBES is currently conducting its first fast track case study on pollination. Specifically, the
Global Pollination Project implements the âProtocol to detect and assess pollination deficits in
crops: a handbook for its useâ (VaissiĂšre et al. 2011), developed through the FAO. The protocol
outlines a unified method to investigate pollination and measure pollination deficits in various
agricultural systems around the world. NINA (the Norwegian Institute for Nature Research)
was tasked with setting up a Norwegian collaboration to implement the protocol in Norway, to
analyse its applicability to Nordic conditions and evaluate its strength in relation to alternative
research strategies. The present report is the result of this effort.
This report does not communicate the final results of the analyses, as they will be conducted in
the two larger âhost-projectsâ that made the implementation of the protocol possible. Instead, it
outlines the rationale of the protocol, and evaluates its potential for providing management relevant
information on pollination deficits, with particular emphasis on Norway. We discuss the
state and trends of pollination dependent crops in Norway, as a background for the need for
pollination in Norwegian Agriculture.
The protocol is general enough to be applied to a wide variety of settings, and we did not experience
any fundamental problems of implementing it in a Nordic setting. We did however notice
challenges to an effective implementation, which might be especially pronounced in a Norwegian
or Scandinavian setting. First, it can be difficult to find a wide enough range of factors that
influence pollinators to efficiently analyse the importance of pollination without resorting to manipulative
treatments. For example, the amount of flower resources and fragmentation of habitat
are factors known to influence pollinators. But many crops are spatially aggregated to relatively
narrow valleys and therefore experience similar surroundings. Secondly, it can be challenging
to find enough replicate farms since Norway is a relatively small agricultural nation.
Thirdly, pollinators in Norway (as in many other parts of the world) are intractably linked to agricultural
and animal husbandry practices that provide a diversity of flowering resources necessary
for pollinating insects, yet these practices and resulting resources in the surrounding landscape
is not sufficiently captured by the survey protocol.
The protocol is designed to estimate differences in yield given differences in pollination, and
various methods are available to approach optimal pollination, that acts as benchmark. Estimating
the effect of pollination on yield is the foundation to understanding the status of pollination
deficits for any crop. The protocol appears to be a successful effort to create a unified
standard of measuring pollination and pollination deficits by this definition. It thus marks a great
improvement for pollination research in agriculture internationally.
However, we argue that additional knowledge is needed for a successful management of pollinators
in agriculture. Firstly, we need to have an understanding of the relationship between pollination
and yield throughout a wide range of pollination levels, beyond what is typically
achieved from a single study that implements the protocol. Here, the unified standard of the
protocol has great potential since it facilitates comparisons and joint analyses of data sets from
different regions. It could be difficult to precisely estimate pollination deficits and to correctly interpret the results, just by employing the protocol in one individual study. Therefore, much of
the protocolâs strength seems to rely on combining datasets and meta-analyses. Secondly, it is
important to be able to put the measured levels of pollination in context with what is reasonably
achievable in a particular region, either through management of natural resources or adding of
domesticated pollinators. An understanding of the factors that influence pollinator levels is here
crucial in order to successfully design effective policy instruments. The protocol itself is not designed
to provide detailed information about these mechanisms, so additional studies are recommended.
Lastly, we point to the need to review the trends of the factors that influence pollinators
in a historical and societal context. When we have 1) established that there is a potential
for increased yield by increasing pollinators (by employing the protocol), we need to know 2)
what governs the levels of pollination in a particular region, and 3) what levels could we reasonably
achieve given the available management actions and policy responses.Ă
ström, J., Dramstad, W., Debella-Gilo, M., Hovstad, K. A., Ă
ström, S. & Rusch, G. M. 2014.
Vurdering av pollineringsunderskudd i Norge. Kapasitetsbygging mot IPBES, med implementering
og metodisk evaluering av FAOs protokoll for Ă„ oppdage og vurdere pollineringsunderskudd
i avlinger.- NINA Rapport 1101. 51 s.
I 2012 finansierte MiljĂždirektoratet en tilleggsmodul til âThe Global Pollination Projectâ som
koordineres av FAO (Food and Agriculture Organization of the United Nations). MĂ„lsetningen
med denne tilleggsmodulen var Ă„ utvide antall land som gjennomfĂžrte undersĂžkelser i henhold
til den protokollen som er utviklet i det internasjonale prosjektet fra 7 til 13. Dette internasjonale
arbeidet sĂžker Ă„ bygge kapasitet for pollineringsstudier og utĂžke kunnskapsgrunnlaget for FNs
plattform for biologisk mangfold og Ăžkosystemtjenester (IPBES), som for tiden gjennomfĂžrer
sin fÞrste case study pÄ pollinering. Spesielt implementerer prosjektet protokollen som er utviklet
gjennom FAO for Ä mÄle pollineringsunderskudd (VaissiÚre et al. 2011). Protokollen skisserer
en enhetlig metode for Ä undersÞke pollinering og mÄle pollineringsunderskudd i ulike jordbrukssystemer
rundt om i verden. NINA (Norsk institutt for naturforskning) fikk samme Ă„r i oppgave
Ă„ sette opp et norsk samarbeid for Ă„ implementere protokollen i Norge, analysere dens
anvendbarhet under nordiske forhold og vurdere protokollens styrke i forhold til alternative
forskningsstrategier. Denne rapporten er et resultat av dette arbeidet.
Denne rapporten kommuniserer ikke de endelige resultatene av analysene, ettersom de vil bli
gjennomfĂžrt i de to stĂžrre "vert-prosjektene", som gjorde gjennomfĂžringen av protokollen mulig.
I stedet, skisserer denne rapporten begrunnelsen for protokollen, og evaluerer dens potensiale
for Ă„ levere relevant informasjon om pollineringsunderskudd til forvaltningen, med sĂŠrlig vekt
pÄ Norge. OgsÄ tilstanden og utviklingen av pollineringsavhengige avlinger i Norge diskuteres,
som en bakgrunn for behovet for pollinering i norsk landbruk.
Protokollen er generell nok til Ă„ brukes i en rekke forskjellige omgivelser, og vi opplever ikke
noen fundamentale problemer med Ă„ implementere den i en nordisk setting. Vi registrerte imidlertid
noen utfordringer knyttet til mulighetene for Ä oppnÄ en effektiv gjennomfÞring, utfordringer
som kan vĂŠre spesielt uttalte under norske eller skandinaviske forhold. For det fĂžrste
kan det vÊre vanskelig Ä finne egnede studieomrÄder der en rekke faktorer som pÄvirker pollinatorer
har stor nok variasjon til Ă„ kunne analysere betydningen av bestĂžvning uten Ă„ ty til manipulerende
behandlinger. Mange avlinger er geografisk samlet, for eksempel i relativt trange
dalfĂžrer og ligger derfor i lignende omgivelser. For det andre, kan det vĂŠre utfordrende Ă„ finne
et stort nok antall gÄrder, siden enkelte av de interessante vekstene har begrenset utbredelse i
Norge.
Protokollen er utformet for Ă„ beregne forskjeller i avlinger gitt forskjeller i pollinering, og ulike
fremgangsmĂ„ter er tilgjengelige for Ă„ nĂŠrme seg âoptimal pollineringâ, som er det foretrukne
referansepunktet. Den estimerte effekten av pollinering pÄ avlingene er grunnlaget for Ä forstÄ
statusen pÄ pollineringsunderskuddet. Protokollen ser ut til Ä vÊre et vellykket forsÞk pÄ Ä
skape en enhetlig standard for mÄling av pollinering og pollineringsunderskudd etter denne definisjonen.
Dette markerer dermed en stor forbedring for pollineringsforskning internasjonalt.
Imidlertid hevder vi at ytterligere kunnskap er nĂždvendig for en vellykket forvaltning av pollinatorer
i landbruket. For det fÞrste mÄ vi ha en forstÄelse av forholdet mellom pollinering og avling
gjennom et bredt spektrum av pollineringsnivÄer, utover det som normalt oppnÄs i en enkelt
studie som implementerer protokollen. Den enhetlige standarden protokollen representerer
har stort potensiale siden det blir lettere Ă„ utfĂžre sammenligninger og felles analyser av datasett
fra forskjellige regioner. Det kan vÊre vanskelig Ä anslÄ presist pollineringsunderskudd og
tolke resultatene bare ved Ă„ bruke protokollen i en enkelt studie. Mye av protokollens styrke
synes Ä bygge pÄ Ä kombinere datasett og lage meta-analyser. For det andre er det viktig Ä
vÊre i stand til Ä sette et erfart nivÄ av bestÞvning i sammenheng med et bestemt omrÄde. En forstÄelse av de faktorene som styrer nivÄer av pollinatorer er avgjÞrende for Ä kunne designe
vellykkede virkemidler. Selve protokollen er ikke utformet for Ă„ gi detaljert informasjon om disse
forhold, sÄ ytterligere studier anbefales. Til slutt peker vi pÄ behovet for Ä gÄ gjennom trender
av hvilke faktorer som pÄvirker pollinatorer i en historisk og samfunnsmessig sammenheng.
NÄr vi har 1) fastslÄtt at det er et potensial for Þkt avling ved Ä Þke tetthet og / eller diversitet av
pollinatorer (ved Ä bruke protokollen), mÄ vi vite 2) hva som regulerer nivÄene av pollinering i
en bestemt region, og 3) hvilke nivÄer vi rimelig kan oppnÄ gitt de tilgjengelige skjÞtselstiltakene
og politiske tiltakene.© Norsk institutt for naturforskning. Publikasjonen kan siteres fritt med kildeangivelse
Assessing Norwegian pollination deficits. Capacity building towards IPBES - implementation and methodological evaluation of the âProtocol to Detect and Assess Pollination Deficits in crops.
-In 2012, the Norwegian Environmental Agency funded an extension to the Global Pollination Project, coordinated by the FAO (Food and Agriculture Organization of the United Nations) to expand the number of connected countries from 7 fully participating to in total 13 countries. This international effort seeks to build capacity for pollination studies and add to the knowledge base for the Intergovernmental Platform for Biodiversity and Ecosystem Services (IPBES). IPBES is currently conducting its first fast track case study on pollination. Specifically, the Global Pollination Project implements the âProtocol to detect and assess pollination deficits in crops: a handbook for its useâ (VaissiĂšre et al. 2011), developed through the FAO. The proto-col outlines a unified method to investigate pollination and measure pollination deficits in vari-ous agricultural systems around the world. NINA (the Norwegian Institute for Nature Research) was tasked with setting up a Norwegian collaboration to implement the protocol in Norway, to analyse its applicability to Nordic conditions and evaluate its strength in relation to alternative research strategies. The present report is the result of this effort.
This report does not communicate the final results of the analyses, as they will be conducted in the two larger âhost-projectsâ that made the implementation of the protocol possible. Instead, it outlines the rationale of the protocol, and evaluates its potential for providing management rel-evant information on pollination deficits, with particular emphasis on Norway. We discuss the state and trends of pollination dependent crops in Norway, as a background for the need for pollination in Norwegian Agriculture.
The protocol is general enough to be applied to a wide variety of settings, and we did not expe-rience any fundamental problems of implementing it in a Nordic setting. We did however notice challenges to an effective implementation, which might be especially pronounced in a Norwe-gian or Scandinavian setting. First, it can be difficult to find a wide enough range of factors that influence pollinators to efficiently analyse the importance of pollination without resorting to ma-nipulative treatments. For example, the amount of flower resources and fragmentation of habi-tat are factors known to influence pollinators. But many crops are spatially aggregated to rela-tively narrow valleys and therefore experience similar surroundings. Secondly, it can be chal-lenging to find enough replicate farms since Norway is a relatively small agricultural nation. Thirdly, pollinators in Norway (as in many other parts of the world) are intractably linked to ag-ricultural and animal husbandry practices that provide a diversity of flowering resources neces-sary for pollinating insects, yet these practices and resulting resources in the surrounding land-scape is not sufficiently captured by the survey protocol.
The protocol is designed to estimate differences in yield given differences in pollination, and various methods are available to approach optimal pollination, that acts as benchmark. Esti-mating the effect of pollination on yield is the foundation to understanding the status of pollina-tion deficits for any crop. The protocol appears to be a successful effort to create a unified standard of measuring pollination and pollination deficits by this definition. It thus marks a great improvement for pollination research in agriculture internationally.
Pollination, Ecosystem services, Bees, Bumble bees, Pollination deficit Protocol, FAO, IPBES, Policy, apple, red clover, Norway, pollinering, Ăžkosystemtjenester, bier, humler, protokoll for polline-ringsunderskudd, FAO, IPBES, eple, rĂždklĂžve
Endring i leveomrÄder for elvesandjeger og stor elvebreddedderkopp ved Gaula. Forekomst og dynamikk av elveÞrer fra 1947 til 2014
Ă
ström, J., Ădegaard, F., Hanssen, O. og Ă
ström, S. 2017. Endring i leveomrĂ„der for elvesandjeger og stor elvebreddedderkopp ved Gaula. Forekomst og dynamikk av elveĂžrer fra 1947 til 2014. â NINA Rapport 1314. 32 s.
Den unike faunaen av invertebrater pÄ sand- og siltbanker langs vassdrag har vÊrt fremhevet som sterkt truet bÄde i nordisk og europeisk sammenheng (Andersen & Hanssen 1994, 2005). Elvesandjeger Cicindela maritima og stor elvebreddedderkopp Arctosa cinerea er karakterarter for disse sÄrbare naturomrÄdene, og begge har rÞdlistekategori «sterkt truet» (EN) i Norsk rÞdliste for arter (2015).
Begge disse artene har historisk hatt store populasjoner langs elva Gaula i SÞr-TrÞndelag, og dagens forekomster er fortsatt viktige pÄ nasjonal basis. MÄlet med denne studien var Ä se om man ved hjelp av flybilder kunne se endringer i artenes leveomrÄder langs Gaula over tid, karakterisere hastigheten i habitatsforandringene og om mulig spore Ärsaken til endringene. Potensielle habitater ble identifisert og utviklingen kartlagt ved hjelp av flybilder fra 1947 til 2014.
Sandhabitater holdes naturlig Ă„pne av forstyrrelser som gjenskaper habitater. Samtidig gror andre habitater igjen. Gjennomgangen av det historiske bildematerialet viser at det har vĂŠrt en betydelig nedgang i mengde og forbindelse mellom egnete habitater, og at spesielt nydanningen av sandomrĂ„der er liten. Habitatmengden har minket med omtrent 37% i omrĂ„det fra StĂžren til utlĂžpet ved Ăysand, og forbindelsen mellom habitatene har samtidig minket med omtrent 62%. Artene har samtidig gĂ„tt sterkt tilbake eller forsvunnet fra flere lokaliteter.
Elveforbygging og utgraving for fiksering av elvelÞpet er sannsynligvis de viktigste Ärsakene til nedgangen i egnete habitater for elvebreddfaunaen. Vassdraget har gjennomgÄtt sÄ store forandringer at det ikke lenger er i stand til Ä meandrere som tidligere. Som en fÞlge av dette har Þkt gjengroing blitt en trussel, sÊrlig med senere tids spredning av den fremmende arten hage-lupin (Lupinus polyphyllus). Forutsetningene for Ä oppnÄ levedyktige bestandsstÞrrelser for elvesandjeger og stor elvebreddedderkopp er dermed sterkt begrenset.
Beskyttelse og skjĂžtsel av sandhabitater er nĂždvendig for Ă„ stanse den negative utviklingen for elvesandjeger og stor elvebreddedderkopp langs Gaula. Det anbefales i tillegg Ă„ samle inn individer fra de fĂ„tall lokaliteter med fortsatt gode bestander og rekolonisere nye habitater med disse. For Ă„ oppnĂ„ en tilfredsstillende bestandssituasjon, kreves sannsynligvis pĂ„ sikt ogsĂ„ en Ăžkning av mengden sandhabitater langs elva.Ă
ström, J., Ădegaard, F., Hanssen, O. and Ă
ström, S. 2017. Habitat changes for Southern dune tiger beetle and Giant riverbank wolf spider at river Gaula. Occurrence and dynamics of riverbanks from 1947 to 2014. â NINA Report 1314. 32 pp.
Sand- and silt-banks along rivers host a unique invertebrate fauna, which is highly threatened in both a Nordic and a European setting (Andersen & Hanssen 1994, 2005). Southern dune tiger beetle, Cicindela maritima, and Giant riverbank wolf spider, Arctosa cinerea, are signature species for these vulnerable habitats, and both are classified as âEndangeredâ (EN) in the Norwegian Red List for Species (2015).
Both species have historically had large populations along the river Gaula in the county of SĂžr-TrĂžndelag, Norway, and the current populations are still important on a national basis. The purpose of this report was to identify changes in the habitat areas of these species along the river Gaula by using areal imagery, characterize the rate of change, and if possible, identify the causes for the changes in habitat. Potential habitats and their development through time was identified from orthophotos from 1947 through 2014.
Sandy habitats are naturally kept open and recreated by disturbances, while others are lost through natural revegetation. Our analysis of the historical photos reveals that there has been a substantial decrease in the amount and connectivity of suitable habitats, and that especially the formation of new habitats has been low. The amount of habitat in the study area, from StĂžren to the river mouth at Ăysand, has decreased by approximately 37%, and the connectivity of habitats has simultaneously decreased by approximately 62%. Populations of both species have been severely reduced or lost from multiple locations along the river during the same time.
Riprapping of the riverbank and excavation of sand are likely the most important causes for the development, which is characterized by a fixating of the river channel, with subsequent decrease of habitat suitable for the riparian invertebrate fauna. The river has been so severely altered that it no longer is able to meander naturally, as it used to. As a result, encroachment by vegetation is an added threat to the species, especially considering the recent spread of the alien invasive species Large-leaved lupine (Lupinus polyphyllus). The potential to achieve long-term self-sus-taining populations of C. maritima and A. cinerea along the river stretch is therefore greatly reduced.
We conclude that protection and maintenance of sandy habitats is necessary to stop the negative development for C. maritima and A. cinerea along the river Gaula. It is further recommended to colonize new habitats from the few source habitats that still have large populations. To reach a satisfactory long term conservation status, it is likely also necessary to increase the amount of sandy habitats along the river.© Norsk institutt for naturforskning Publikasjonen kan siteres fritt med kildeangivels
Habitatforbedrende tiltak pÄ LangÞra N, StjÞrdal kommune. Effekt pÄ stor elvebreddedderkopp.
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ström, S. & Hanssen, O. 2018. Habitatforbedrende tiltak pÄ LangÞra N, StjÞrdal kommune. Effekt pÄ stor elvebreddedderkopp. NINA Rapport 1566. Norsk institutt for naturforskning.
Stor elvebreddedderkopp, Arctosa cinerea, er en sterkt truet art som i Norge kun finnes i TrĂžndelag. Edderkoppen er knyttet til ulike sandâ og grusdominerte elveavsetninger langs stĂžrre elver og sandstrender ved elveutlĂžp. En viktig lokalitet for arten er LangĂžra N i StjĂžrdal kommune. LangĂžra er delt i to av en flystripe, og vestsiden av den nordre delen utgjĂžres av en 1,3 km lang sandstrand hvor arten har en av sine stĂžrste bestander. Denne sandstranden er i ferd med Ă„ bli gjengrodd av de fremmede og invaderende planteartene hagelupin og rynkerose, noe som er en trussel for bestanden av stor elvebreddedderkopp. Med hensikt Ă„ beskytte arten satte Forsvarsbygg i gang tiltak vĂ„ren 2017, ved Ă„ fjerne hagelupin og rynkerose pĂ„ et 3,6 da stort areal pĂ„ den bredeste delen av sandstranden pĂ„ LangĂžra N. Denne rapporten beskriver bestanden av stor elvebreddedderkopp fra tre registreringer i lĂžpet av 16 mĂ„neder etter at tiltaket med rydding av hagelupin og rynkerose ble utfĂžrt.
Allerede fĂžrste hĂžsten etter tiltaket hadde rekoloniseringen av stor elvebreddedderkopp pĂ„ det ryddete arealet begynt. Ăvrige Ă„pne sandflater pĂ„ LangĂžra N hadde da til dels hĂžye tettheter av edderkopparten. VĂ„ren 2018, ett Ă„r etter tiltaket, var det fĂ„ funn av edderkoppen, hvilket stemmer overens med tidligere erfaringer, som ogsĂ„ har vist lave forekomster av arten om vĂ„ren. Ved registreringen hĂžsten 2018 var antall edderkopper fordoblet pĂ„ det ryddete arealet sammenlignet med hĂžsten 2017, selv om det totalt sett pĂ„ LangĂžra N ble registrert lavere tetthet i 2018 enn i 2017. Tellingen viser sĂ„ledes at rekoloniseringen av det ryddete arealet har fortsatt. Dersom dette arealet fĂ„r forbli fritt fra de to fremmede planteartene, og bestĂ„ av en mosaikk med Ă„pne flater og stedegen vegetasjon, forventes det at stor elvebreddedderkopp vil fĂ„ tilbake en del av sitt tapte potensiale pĂ„ LangĂžra N. For fremtidig rydding i dette arealet frarĂ„des bruk av maskiner, mens manuell luking anbefales.Ă
ström, S. & Hanssen, O. 2018. Habitat enhancing measures at LangÞra N, StjÞrdal municipality. Effect on Arctosa cinerea. NINA Report 1566. Norwegian Institute for Nature Research.
The endangered spider species Arctosa cinerea is in Norway only found in the county of TrĂžndelag. The spider inhabits sand- and shingle-covered riverbeds along the larger rivers and sandy beaches at the river ends. An important locality for the species is LangĂžra N in StjĂžrdal municipality. LangĂžra is divided into two parts by a flight strip, and the west side of the northern part is made up of a 1.3 km long sandy beach where the species has one of its largest populations. This sandy beach is being overgrown by the alien and invasive plant species Lupinus polyphyllus and Rosa rugosa, which is threatening the population of A. cinerea. With the intention of protecting the spider population there, the Norwegian Defence Estates Agency launched measures in the spring of 2017 by removing the invasive plant species on a 3600 m2 area on the widest part of the sandy beach at LangĂžra N. This report describes the population of A. cinerea at LangĂžra N during a period of 16 months after the measures were performed.
Already the first autumn after the measures, the recolonization of A. cinerea onto the cleared area had begun. Other open sand surfaces on LangĂžra N had partly high densities of the spider species. In spring 2018, one year after the measures, there were few records of the spider. This is consistent with previous experiences, which have also revealed low numbers of this species in spring. At the spider recordings in the autumn of 2018, the number of spiders had doubled on the cleared area compared with the fall of 2017, although the number of spiders throughout LangĂžra N was recorded lower in 2018 than in 2017. This illustrates that the recolonization of the cleared area has continued. If this area remains free from the two alien plant species, and consists of a mosaic with open surfaces and native plant species, it is expected that A. cinerea will recoup some of its lost potential at LangĂžra N. For future measures in the cleared area, the use of machines is not recommended. Instead, invasive plants should be removed manually