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Dive into the research topics where Gudmundur Halldorsson is active.

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Featured researches published by Gudmundur Halldorsson.


Ecology and Society | 2013

Ecological and social dimensions of ecosystem restoration in the nordic countries

Dagmar Hagen; Kristín Svavarsdóttir; Christer Nilsson; Anne Tolvanen; Karsten Raulund-Rasmussen; Ása L. Aradóttir; Anna Maria Fosaa; Gudmundur Halldorsson

An international overview of the extent and type of ecological restoration can offer new perspectives for understanding, planning, and implementation. The Nordic countries, with a great range of natural conditions but historically similar social and political structures, provide an opportunity to compare restoration approaches and efforts across borders. The aim of this study was to explore variation in ecological restoration using the Nordic countries as an example. We used recent national assessments and expert evaluations of ecological restoration. Restoration efforts differed among countries: forest and peatland restoration was most common in Finland, freshwater restoration was most common in Sweden, restoration of natural heathlands and grasslands was most common in Iceland, restoration of natural and semi-cultural heathlands was most common in Norway, and restoration of cultural ecosystems, mainly abandoned agricultural land, was most common in Denmark. Ecological restoration currently does not occur on the Faroe Islands. Economic incentives influence ecological restoration and depend on laws and policies in each country. Our analyses suggest that habitat types determine the methods of ecological restoration, whereas socio-economic drivers are more important for the decisions concerning the timing and location of restoration. To improve the understanding, planning, and implementation of ecological restoration, we advocate increased cooperation and knowledge sharing across disciplines and among countries, both in the Nordic countries and internationally. An obvious advantage of such cooperation is that a wider range of experiences from different habitats and different socio-economic conditions becomes available and thus provides a more solid basis for developing practical solutions for restoration methods and policies.


Scandinavian Journal of Forest Research | 2000

Ectomycorrhizae reduce damage to Russian larch by Otiorhyncus larvae.

Gudmundur Halldorsson; Halldór Sverrisson; Gudrídur Gyda Eyjólfsdóttir; Edda Sigurdis Oddsdottir

The effect of ectomycorrhizae on damage caused by Otiorhyncus larvae and on plant growth was evaluated in a 3-yr field experiment. Russian larch seedlings, inoculated with ectomycorrhizal fungi, were compared with uninoculated plants. Assessment of larval damage at the end of the first growing season showed a significant effect of treatment on damage intensity, but not on damage incidence: 11.2% of uninoculated seedlings were severely damaged, but only 3.5% of inoculated plants. There was a significant effect of treatment on plant mortality. The accumulated mortality at the end of the third growing season was 34.5% for uninoculated plants, but 17.6% for inoculated plants. The height increment of inoculated plants (4.5 cm) was significantly greater than that of uninoculated plants (2.7 cm) in the first growing season. No difference in height increment between treatments was observed during the second and third growing seasons.


Agricultural and Forest Entomology | 2010

The effects of insect pathogenic soil fungi and ectomycorrhizal inoculation of birch seedlings on the survival of Otiorhynchus larvae

Edda Sigurdis Oddsdottir; Jørgen Eilenberg; Robin Sen; Gudmundur Halldorsson

1 Weevil larvae of the genus Otiorhynchus are a serious problem in agriculture and forestry, causing damage to a wide range of plant species, primarily by larval feeding on roots. Otiorhynchus larvae are a serious pest in forest plantations in Iceland, causing 10–20% mortality of newly‐planted seedlings. 2 We studied the effects of soil fungi on the survival of Otiorhynchus sulcatus larvae. The larvae were introduced into pots with birch seedlings grown in: (i) nursery peat; (ii) nursery peat inoculated with three different species of ectomycorrhizal fungi; (iii) nursery peat inoculated with insect pathogenic fungi; (iv) nursery peat inoculated with ectomycorrhizal fungi and insect pathogenic fungi; and (v) nursery peat inoculated with natural forest soil from Icelandic birch woodland. 3 Larval survival was negatively affected by inoculation of: (i) the ectomycorrhizal fungus Laccaria laccata; (ii) the ectomycorrhizal fungus Cenococcum geophylum; (iii) the insect pathogenic fungus Metarhizium anisopliae; and (iv) forest soil. Inoculation with the ectomycorrhizal fungus Phialophora finlandia did not have any significant effect on larval survival. No significant synergistic effect was found between insect pathogenic and ectomycorrhizal fungi. 4 It is concluded that ectomycorrhizal and insect pathogenic fungi have a significant potential in biological control of Otiorhynchus larvae in afforestation areas in Iceland. Further studies are needed to establish the effect of these fungi in the field and to analyse how mycorrhizal fungi affect root‐feeding larvae.


Archive | 2015

Soil Carbon Sequestration – for climate, food security and ecosystem services

Gudmundur Halldorsson; Bjarni Didrik Sigurdsson; Leena Finér; Jon Gudmundsson; Thomas Kätterer; Bal Ram Singh; Lars Vesterdal; Andres Arnalds

Soil carbon sequestration and preservation of present stocks reduces net global greenhouse gas emission and can contribute significantly to both Nordic and international goals of limiting serious c ...


Archive | 2008

AFFORNORD : Effects on Ecosystems, Landscape and Rural Development

Gudmundur Halldorsson; Edda Sigurdis Oddsdottir; Bjarni Didrik Sigurdsson

The Nordic project AFFORNORD studied the effects of afforestation on ecosystems, landscape and rural development in the years 2004–2006. Forests play a major role in the environment and economy of ...


Ecology and Society | 2013

Drivers of ecological restoration: lessons from a century of restoration in Iceland.

Ása L. Aradóttir; Thorunn Petursdottir; Gudmundur Halldorsson; Kristín Svavarsdóttir; Olafur Arnalds


Journal of Invertebrate Pathology | 2001

Geographical Distribution and Host Range of Entomophthorales Infecting the Green Spruce Aphid Elatobium abietinum Walker in Iceland

Charlotte Marie Bisgaard Nielsen; Jørgen Eilenberg; Susanne Harding; Edda Sigurdis Oddsdottir; Gudmundur Halldorsson


Applied Soil Ecology | 2010

Early reduction of Otiorhynchus spp. larval root herbivory on Betula pubescens by beneficial soil fungi.

Edda Sigurdis Oddsdottir; Jørgen Eilenberg; Robin Sen; Susanne Harding; Gudmundur Halldorsson


Restoration Ecology | 2018

Colonization of woodland species during restoration: seed or safe site limitation?: Seed or safe site limitation

Ása L. Aradóttir; Gudmundur Halldorsson


Land Degradation & Development | 2017

Successes and failures in rangeland restoration- an Icelandic case study

Thorunn Petursdottir; Ása L. Aradóttir; Susan Catherine Baker; Gudmundur Halldorsson; Ben Sonneveld

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Ása L. Aradóttir

Agricultural University of Iceland

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Bjarni Didrik Sigurdsson

Agricultural University of Iceland

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Thorunn Petursdottir

Agricultural University of Iceland

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Kristín Svavarsdóttir

Natural Resources Conservation Service

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Robin Sen

Manchester Metropolitan University

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Olafur Arnalds

Agricultural University of Iceland

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