Public procurement of interregional passenger transports and Swedish transport policy in practice since 1988: Towards new regional patterns?

Traditionally, Sweden has not belonged to the Anglo-Saxon market-centred welfare model. However, Sweden is today among the European countries with the highest degree of public outsourcing and procurement of welfare services via competitive markets. The aim of this article is to investigate the development of procurement of inter-regional railway passenger transports and to explore how this affected the allocation of public resources since 1988. Did procurement only increase the efficiency of policy implementation (same or better service for the same or lower price), or did it also indirectly affect the outcome of policy (the relative allocation of public resources between regions and modes of transportation)? The article shows that procurement enabled new regional interest groups to affect the outcome of policy, which in turn changed the allocation of subsidies to railway passenger transports. The results are relevant for the future organization of the transport sector to avoid unwanted side effects from procurement and other new organizational models.

Spatial heterogeneity enhance robustness of large multi-species ecosystems

Understanding ecosystem stability and functioning is a long-standing goal in theoretical ecology, with one of the main tools being dynamical modelling of species abundances. With the help of spatially unresolved (well-mixed) population models and equilibrium dynamics, limits to stability and regions of various ecosystem robustness have been extensively mapped in terms of diversity (number of species), types of interactions, interaction strengths, varying interaction networks (for example plant-pollinator, food-web) and varying structures of these networks. Although many insights have been gained, the impact of spatial extension is not included in this body of knowledge. Recent studies of spatially explicit modelling on the other hand have shown that stability limits can be crossed and diversity increased for systems with spatial heterogeneity in species interactions and/or chaotic dynamics. Here we show that such crossing and diversity increase can appear under less strict conditions. We find that the mere possibility of varying species abundances at different spatial locations make possible the preservation or increase in diversity across previous boundaries thought to mark catastrophic transitions. In addition, we introduce and make explicit a multitude of different dynamics a spatially extended complex system can use to stabilise. This expanded stabilising repertoire of dynamics is largest at intermediate levels of dispersal. Thus we find that spatially extended systems with intermediate dispersal are more robust, in general have higher diversity and can stabilise beyond previous stability boundaries, in contrast to well-mixed systems

Spatial coherence and the persistence of high diversity in spatially heterogeneous landscapes

Our planet hosts a variety of highly diverse ecosystems. The persistence of high diversity is generally attributed to factors such as the structure of interactions among species and the dispersal of species in metacommunities. Here, we show that large contiguous landscapes-that are characterized by high dispersal-facilitate high species richness due to the spatial heterogeneity in interspecies interactions. We base our analysis on metacommunities under high dispersal where species densities become equal across habitats (spatially coherent). We find that the spatially coherent metacommunity can be represented by an effective species interaction-web that has a significantly lower complexity than the constituent habitats. Our framework also explains how spatial heterogeneity eliminates differences in the effective interaction-web, providing a basis for deviations from the area-heterogeneity tradeoff. These results highlight the often-overlooked case of high dispersal where spatial coherence provides a novel mechanism for supporting high diversity in large heterogeneous landscapes

Eviga vänner, förgängliga län : Prioriteringar i borgherrarnas verksamhetskultur på Raseborg ca 1390-1434

Peer reviewe

Grödans kontra odlingssystemets effekt på frilevande nematoder

Nematodes are perhaps the most common animals in the world. Nematode populations can reach densities up to several millions per square meter in the soil. There are many factors which affect nematode communities in arable soil with respect to diversity and population size. Factors like tillage, crop, fertilization, nutrient status and moisture in the soil all have an impact on soil biology and in this way also have effects on the nematode community. This study is based on three different parts, soil samples taken in March 2012 and March 2013, soil samples taken monthly during the growth season of 2013 in bare fallow plots and a pot experiment. All soil samples and the soil in the pot experiment was taken from a long-term field trial in Önnestad which is located nearby Kristianstad, Sweden. The aim of this study was to investigate if cropping system or crop had the greatest effect on the abundance and diversity of nematode communities in arable soil. The hypothesis tested was that crop had a main impact on plant-feeding nematodes, especially when a non-host crop was grown or a bare fallow was establish. The field trial in Önnestad was established in 1987 and includes 5 cropping systems (2 conventional and 3 organic) with six year crop rotations. In March 2012, soil samples were taken in the Önnestad field trial and high numbers of plant-parasitic nematodes were observed. One year later, soil samples were again taken. The samples from 2012 and 2013 differed greatly in nematode abundances, and the two years were analyzed statistically to find out if cropping system had some effect on the differences between the 2012 and 2013 samplings. There were differences between the years for some nematode families and those differences were all connected with the fact that ley was present in the crop rotation. This indicates that ley has a positive effect on some free-living nematode families. Before the growing season of 2013, the crop rotations were reorganized because of the high numbers of plant-parasitic nematodes, especially root-knot nematodes. This resulted in plots with bare fallow in three of the crop rotations in 2013. In those bare fallows plots, soil samples were taken monthly and examined to determine how free-living nematodes were affected by this management. In this way, the free-living nematode populations were studied based on how they fluctuate during the season under bare fallow. The pot experiment that was preformed had four different crops; red clover, white clover, ryegrass and bare fallow and the soil in the pots where taken from the plots with bare fallow in the Önnestad field trial. Free-living nematodes were counted and classified after what they eat and in this way the population density of different free-living nematodes could be determined in relation to cropping system and crop. The results and conclusions of this study are that crop rotations including ley have a positive effect on the abundance of free-living herbivorous nematodes and the nematode population density in general. This means that cropping systems have a role in the complexity and density of free-living nematode populations. The study also showed that legumes may have a positive effect on population density of free-living nematodes regardless what they eat. There is also a crop effect on the community of free-living nematodes in the pot experiment. Herbivores had a lower abundance in pots with bare fallow in contrast to pots with a crop. This clear result didn’t show in the analysis of the season sampling. It’s possible that bare fallow need a longer time to give this effect in practice.Nematoder är ett av de mest vanligt förekommande djuren i världen. De kan i marken uppnå populationsdensiteter på flera miljoner individer per kvadratmeter. I jordbruksmark finns det flera olika faktorer som påverkar nematodsamhället i avseende på diversitet och populationsstorlek. Faktorer som jordbearbetning, gröda, gödsling, näringsstatus i marken samt markfukt har alla en avgörande roll för markbiologin och på detta sätt även en påverkan på markens nematodsamhälle. Denna uppsats med tillhörande försök är baserad på tre olika delar, jordprover tagna i mars 2012 respektive 2013, jordprover tagna månadsvis i svartträda i ett odlingssystemsförsök under 2013 års odlingssäsong samt ett krukförsök. Alla jordprover och all jord i försöket är tagna från ett långliggande fältförsök i Önnestad som ligger vid Kristianstad. Syftet med uppsatsen var att undersöka huruvida odlad gröda kontra odlingssystem påverkar nematodsamhället. Hypotesen som testades var att grödan har betydelse för mängden och diversiteten av nematodsamhället, och då i synnerhet för växtätande nematoder då en icke-värdväxt odlades samt svartträda var anlagd. Försöket i Önnestad är ett odlingssystemsförsök som etablerades 1987 och som består av 5 olika odlingssystem (2 konventionella och 3 ekologiska) där alla 5 leden har 6-åriga växtföljder. I mars 2012 togs jordprover i försöket som visade sig innehålla stora mängder av växtpatogena nematoder. Ett år senar togs ytterligare jordprover som visade sig skilja dramatiskt från 2012 års prover i avseende på nematodförekomst. I denna uppsats analyserades proverna för att undersöka eventuella skillnader mellan odlingssystemen. Det visade sig att det fanns skillnader mellan åren för olika nematodfamiljer som går att förklara med att en flerårig vall finns i växtföljden. Detta indikerar att vallodling kan ha en positiv effekt för enskilda nematodfamiljer. Inför odlingssäsongen 2013 gjordes förändringar i växtföljden i försöket i Önnestad på grund av den höga nematodförekomsten som uppdagades 2012. Det var framförallt rotgallnematodsförekomsten som oroade och i tre av odlingssystemen anlades därför svartträda. I dessa svartträdor togs sedan månadsvisa jordprover för att undersöka hur frilevande nematoder påverkas av en svartträda. På detta sätt studerades även hur de frilevande nematoderna fluktuerade under en odlingssäsong i svartträda. Krukförsöket som anlades bestod av fyra grödor vitklöver, rödklöver, engelskt rajgräs och svartträda och jorden som användes till försöket kom från svartträdorna i Önnestadsförsöket. Frilevande nematoder räknades och klassificerades efter födogrupp och på detta sätt kunde populationsdensiteten av olika frilevande nematoder bestämmas i relation till odlingssystem och gröda. Resultatet och slutsatsen av denna studie är att växtföljder som innehåller vall har en positiv effekt på växtätande frilevande nematoder och att vall generellt har en positiv effekt på olika nematoders populationsdensitet. Detta betyder att odlingssystemet har en roll i de frilevande nematodsamhällena med avseende på dess komplexitet och densitet. Studien visar även att baljväxter möjligen har en positiv effekt på frilevande nematoder oavsett vilken födogrupp de tillhör. Krukförsöket visar även att grödan har betydelse, växtätande nematoder hade en lägre populationsdensitet i krukor med svartträda i relation till krukor med gröda. Detta resultat visade sig dock inte i analysen av säsongsproverna. Det är möjligt att svartträda måste ligga under en längre tid för att ge effekt i praktiken

Alternativa värdväxter för växtpatogener i svensk växtodling

Kraven på hög kvalité och höga skördar har länge varit en drivkraft för att effektivisera och utveckla växtodlingen. Lantbrukare har i alla tider försökt att minska de negativa effekter som ogräs, insekter, svampar, bakterier och virus har haft på skörden. Bekämpningen har sett olika ut genom åren och utvecklats utifrån kunskaper om skadegörarna och ogräsen. Växtföljder, jordbearbetning samt bekämpning kemiskt och mekaniskt är idag de främsta åtgärderna. Målet med denna litteraturstudie är att ge en klarare bild av samspelet mellan besvärliga växtpatogener och dess värdväxter i dagens svenska lantbruk. På detta vis kan man dra slutsatser om huruvida ogräsfloran på ett fält har betydelse för vilka svamp- och virussjukdomar som kan tänkas uppkomma på detta fält. Studien visade att flertalet svampsjukdomar och virusinfektioner kan drabba flera av våra vanligaste åkerogräs, men även arter som odlas i vall kan angripas. Hur stor betydelse detta har för patogenens spridning och livscykel är beroende av flera faktorer bl.a. klimat samt patogenen i sig själv och val av värdväxten. Det är svårt att säga något generellt och ge konkreta odlingsråd med avseende på ämnet. Arbetet är upplagt så att vissa patogener är granskade på grundligare nivå och behandlas separat i uppsatsen. Dessa är utvalda dels på grund av att de angriper olika grödor och har intressanta särdrag. Flertalet av patogenerna och dess värdväxter presenteras endast i tabellform.Requirements for high quality and high yield have for a long time been a driving force to improve and develop crop production. Farmers have during all times tried to reduce yield losses caused by weeds, insects, fungus, viruses and bacteria. The main control of them is based on of knowledge about their biology. Today we often use crop rotation, tillage and mechanic or chemical control to regulate them. The aim of this essay is to give a summarizing picture of the interactions between plant pathogens and their hosts in Sweden. In this way a conclusion could be drawn on the basis on weed presence in a field and the risk of contamination of the crop from pathogens using weeds as host plants. One conclusion is that most of the common Swedish weeds could be an alternative host for fungus diseases and virus infections, in addition crops that are used in leys could be hosts for diseases. How important this is for the lifecycle of the pathogen depends on the host and of course on the pathogen. It’s hard to give any practical advises and even harder to draw general conclusions. This essay presents some host-pathogen interactions thoroughly, while other examples are presented only in tabular form. The former are chosen based on which crop they infect and interesting feature

Diseases on Christmas trees in southern Sweden and western North Carolina - with emphasis on Phytophthora root rot and Neonectria canker

Surveys and inoculation experiments were conducted in Sweden and North Carolina to investigate diseases of Christmas trees, focusing on Phytophthora root rot and Neonectria canker. Christmas tree production is a significant business in North Carolina and for individual growers in Sweden. In North Carolina, six Phytophthora species were discovered on symptomatic Fraser fir (Abies fraseri), three of which were new to the region (P. europaea, P. citrophthora, and P. sansomeana). Phytophthora cinnamomi was the dominating species causing disease, but P. cryptogea also contributed significantly to Fraser fir loss. According to a questionnaire survey, 88% of Christmas tree growers had Phytophthora root rot in their fields. To combat Phytophthora root rot in North Carolina eastern white pine is planted on heavily infested sites as an alternative to Fraser fir. After screening eastern white pine families for P. cinnamomi tolerance, it is evident that families specifically selected for tolerance will reduce problems with Phytophthora root rot. In Sweden, 16 disease-causing pathogens and six pests were discovered in a survey of Christmas tree plantations. Further studies focused on Phytophthora root rot and Neonectria canker. Five identified Phytophthora species were isolated from waterways and soil samples. In addition, P. megasperma was isolated from a young diseased Norway spruce (Picea abies). Inoculation tests with P. cryptogea, P. megasperma, P. plurivora showed minor disease development. The Phytophthora species found were not widespread and it is currently a minor problem for Swedish Christmas tree growers. From Norway spruce trees with top-dieback, Neonectria fuckeliana was commonly isolated. On Nordmann fir, Neonectria neomacrospora was found. Inoculation studies using N. fuckeliana and N. neomacrospora on Norway spruce and Nordmann fir, respectively, demonstrated that both pathogens caused disease, while a second N. fuckeliana inoculation study found symptom development to be minor. For rapid and reliable identification of N. fuckeliana in northern Europe, a species-specific PCR-based test was developed

Stump treatment with the root rot antagonist phlebiopsis gigantea : - sensitivity of P. gigantea spores to high pressure stress; - reduced water consumption for stump treatment

Stump treatment today requires large quantities of clean water mixed with the protective product Rotstop, to fully cover the stump surface. In order to reduce the water consumption without reducing the coverage of the stump surface, the pressure in the stump treatment device can be increased. Therefore, the Phlebiopsis gigantea (Fr.) Jül. suspension used as a biological control agent to prevent Heterobasidion annosum (Fr.) Bref. infection was pressure-tested. The pressurized suspensions were compared with the control suspensions and the survival was monitored by measuring oidia germination on agar medium. Pressures up to 150 bars (15 000 kPa) were tested and showed no negative effects on the survival of the P. gigantea spores. Three Phlebiopsis gigantea suspensions, with the same quantity of P. gigantea spores but with different water amounts (the recommended water amount 1 l/m2 stump surface, a reduced amount of 0.5 l/m2 and an even more reduced amount of 0.25 l/m2), were compared with each other. This was done to investigate if it is possible to reduce the water consumption for stump treatment and thereby reduce stump treatment costs. The experiment was conducted on stem pieces (billets) of Norway spruce (Picea abies (L.) Karst.) in a laboratory, and the amount of Heterobasidion infection was screened. Results showed no difference between using 1, 0.5 or 0.25 l/m2.Vid stubbehandling går det åt en stor mängd vatten. Om trycket i apparaturen ökas kan vattenförbrukningen minskas utan att täckningsgraden av stubbenytan försämras. I denna studie trycktestades Phlebiopsis gigantea (Fr.) som används vid biologisk stubbehandling för att förhindra angrepp av rotrötesvampen Heterobasidion annosum (Fr.) Bref. De trycksatta P. gigantea sporerna jämfördes mot en kontroll utan tryck. Groningsförsök på agar-plattor visade att tryck upp till 150 bar (15 000 kPa) inte påverkade sporerna. Tre olika behandlingar jämfördes med varandra för att undersöka om det var möjligt att reducera vattenåtgången vid stubbehandling. En vanlig behandling med 1 l/m2 stubbyta, en behandling med 0.5 l/m2 och en behandling med 0.25 l/m2 jämfördes med varandra. Mängden P. gigantea sporer var exakt den samma för de olika behandlingarna. Experimentet utfördes på stambitar av Gran (Picea abies (L.) Karst.) i ett laboratorium och mängden Heterobasidion-infektion mättes. Resultatet visade ingen skillnad mellan att använda 1, 0.5 eller 0.25 l/m2

Eviga vänner, förgängliga län : Prioriteringar i borgherrarnas verksamhetskultur på Raseborg ca 1390-1434

Peer reviewe

Stability of ecosystems enhanced by species-interaction constraints

Ecosystem stability is a central question both in theoretical and applied biology. Dynamical systems theory can be used to analyze how growth rates, carrying capacities, and patterns of species interactions affect the stability of an ecosystem. The response to increasing complexity has been extensively studied and the general conclusion is that there is a limit. While there is a complexity limit to stability at which global destabilisation occurs, the collapse rarely happens suddenly if a system is fully viable (no species is extinct). In fact, when complexity is successively increased, we find that the generic response is to go through multiple single-species extinctions before a global collapse. In this paper we demonstrate this finding via both numerical simulations and elaborations of theoretical predictions. We explore more biological interaction patterns, and, perhaps most importantly, we show that constrained interaction structures-a constant row sum in the interaction matrix-prevent extinctions from occurring. This makes an ecosystem more robust in terms of allowed complexity, but it also means singles-species extinctions do not precede or signal collapse-a drastically different behavior compared to the generic and commonly assumed case. We further argue that this constrained interaction structure-limiting the total interactions for each species-is biologically plausible