Papers by Knut Anders Hovstad
Plant Ecology, Sep 6, 2007
Global Biogeochemical Cycles
Understanding the chemical composition of our planet's crust was one of the biggest questions... more Understanding the chemical composition of our planet's crust was one of the biggest questions of the 20th century. More than 100 years later, we are still far from understanding the global patterns in the bioavailability and spatial coupling of elements in topsoils worldwide, despite their importance for the productivity and functioning of terrestrial ecosystems. Here, we measured the bioavailability and coupling of thirteen macro‐ and micronutrients and phytotoxic elements in topsoils (3–8 cm) from a range of terrestrial ecosystems across all continents (∼10,000 observations) and in response to global change manipulations (∼5,000 observations). For this, we incubated between 1 and 4 pairs of anionic and cationic exchange membranes per site for a mean period of 53 days. The most bioavailable elements (Ca, Mg, and K) were also amongst the most abundant in the crust. Patterns of bioavailability were biome‐dependent and controlled by soil properties such as pH, organic matter conte...
Journal of Environmental Management, 2022
Roadsides, in particular those being species-rich and of conservation value, are considered to im... more Roadsides, in particular those being species-rich and of conservation value, are considered to improve landscape permeability by providing corridors among habitat patches and by facilitating species' dispersal. However, little is known about the potential connectivity offered by such high-value roadsides. Using circuit theory, we modelled connectivity provided by high-value roadsides in landscapes with low or high permeability in south-central Sweden, with 'permeability' being measured by the area of semi-natural grasslands. We modelled structural connectivity and, for habitat generalists and specialists, potential functional connectivity focusing on butterflies. We further assessed in which landscapes grassland connectivity is best enhanced through measures for expanding the area of high-value roadsides. Structural connectivity provided by high-value roadsides resulted in similar patterns to those of a functional approach, in which we modelled habitat generalists. In landscapes with low permeability, all target species showed higher movements within compared to between grasslands using high-value roadsides. In landscapes with high permeability, grassland generalists and specialists showed the same patterns, whereas for habitat generalists, connectivity provided by high-value roadsides and grasslands was similar. Increasing the ratio of high-value roadsides can thus enhance structural and functional connectivity in landscapes with low permeability. In contrast, in landscapes with high permeability, roadsides only supported movement of specialised species. Continuous segments of high-value roadsides are most efficient to increase connectivity for specialists, whereas generalists can utilize also short segments of high-value roadsides acting as stepping-stones. Thus, land management should focus on the preservation and restoration of existing semi-natural grasslands. Management for enhancing grassland connectivity through high-value roadsides should aim at maintaining and creating high-value roadside vegetation, preferably in long continuous segments, especially in landscapes with low permeability.
Rapporten oppsummerer resultatene fra prosjektet «Tiltak mot tett mosedekke i kulturmarkseng – ut... more Rapporten oppsummerer resultatene fra prosjektet «Tiltak mot tett mosedekke i kulturmarkseng – utprøving av metoder som ivaretar det biologiske mangfoldet». Prosjektet er finansiert av Landbruksdirektoratet, og ble gjennomført i Trøndelag og Møre og Romsdal i perioden 2016 – 2019. Utfordringen med tett mosedekke er ingen ny problemstilling, men stadig flere rapporterer nå om at dette har blitt et økende problem i de artsrike slåttemarkene, til tross for at de skjøttes. På sikt kan denne utviklinga få negative konsekvenser for det biologiske mangfoldet, fordi det tette mosedekket fører til mangel på egna frøspiringshabitater for gras og urter. Målsetningen med prosjektet var derfor å teste ut ulike metoder som kan egne seg for å bekjempe det tette mosedekket, og samtidig undersøke hvilke effekter de ulike tiltakene har for artsmangfoldet. Hvilke konsekvenser det tette mosedekket har for frøspiringen ble også undersøkt...…
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Ecosystem Service indicators for grasslands in relation to ecoclimatic regions and land use systems Sylvain Plantureux, Alberto Bernues, Olivier Huguenin-Elie, Knut Anders Hovstad, Johannes Isselstein, Davy Mccraken, Olivier Therond, Vackar David
SummaryIt is common practice for ecologists to examine species niches in the study of community c... more SummaryIt is common practice for ecologists to examine species niches in the study of community composition. The response curve of a species in the fundamental niche is usually assumed to be quadratic. The center of a quadratic curve represents a species’ optimal environmental conditions, and the width its ability to tolerate deviations from the optimum.Most multivariate methods assume species respond linearly to the environment of the niche, or with a quadratic curve that is of equal width and height for all species. However, it is widely understood that some species are generalists who tolerate deviations from their optimal environment better than others. Rare species often tolerate a smaller range of environments than more common species, corresponding to a narrow niche.We propose a new method, for ordination and fitting Joint Species Distribution Models, based on Generalized Linear Mixed-Effects Models, which relaxes the assumptions of equal tolerances and equal maxima.By explic...
Journal of European Landscapes, 2020
This is an open access article under the terms of the Creative Commons Attribution License, which... more This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Acta Horticulturae, 2017
In a project focusing on semi cultivation of European blueberry (EB) from 2008 to 2011, was a bot... more In a project focusing on semi cultivation of European blueberry (EB) from 2008 to 2011, was a botanical survey undertaken in two experimental fields in the municipalities Snåsa and Lierne in the county of Nord-Trøndelag, Norway. The focus was mainly on growth of EB and Vaccinium vitis-idaea. We examined effects of fertilization and cutting of EB to evaluate if established practices in the semi-cultivation of the wild American lowbush blueberry (Vaccinium angustifolium), also had potential for semi-cultivation of EB. We assigned four levels of fertilization randomly per block, with five replications. The Snåsa and the Lierne fields were clear-cut, twenty-five and five years prior of the survey, respectively. We pruned the remaining trees and shrubs to the ground when the experiment was established. Before application of fertilizer and cutting, we conducted a vegetation survey recording percentage cover of all plant species. Furthermore, we recorded maximum, minimum, and middle canopy height of EB and estimated percent cover and thickness of plant litter at the forest floor in 2008 and 2011. The survey consisted of three plots of one m 2. We placed each of them in the center of a fertilization plot, randomly distributed across the four fertilization treatments of each block at both sites. Twenty-six species were present in the fields, and the changes in botanical diversity influenced by year, location, fertilization, pruning of shrubs; the Snåsa trial were divided in two sites with three blocks in site one and two in site 2. Suggestions of how development of European blueberry in forest fields could be strengthened, and subsequently how the competitors could be weakened are presented. We showed that Pruning of EB decreased canopy cover, maximum-and middle-height, which was still lower three years after pruning than unpruned plants, and that V. vitis-idaea had a lower nutrient demand than EB.
Journal of Land Use Science, 2018
The long history of human land use have had a strong influence on ecosystems and landscapes in th... more The long history of human land use have had a strong influence on ecosystems and landscapes in the boreal forest region of Northern Europe and created semi-natural habitats of high conservation value. In this study, we quantify land-cover change and loss of semi-natural grassland in an agricultural landscape (6.2 km 2) in the boreal region of Norway from 1960 to 2015, and document a 49.1% loss of area that was seminatural grassland in 1960. The remaining semi-natural grasslands became smaller and the connectivity between them decreased. Intensification and abandonment of agricultural land use were of approximately equal importance for the loss of semi-natural grassland although the relative contribution of these processes depended on the topography and distance to farmsteads. The study provides an example of how change in land cover can be estimated and key drivers identified on a scale that is relevant for implementation of management and conservation measures.
Acta Agriculturae Scandinavica, Section A - Animal Science, 2009
Plant and Soil, 2019
Aim Root growth strategies may be critical for seeding survival and establishment under dry condi... more Aim Root growth strategies may be critical for seeding survival and establishment under dry conditions, but these strategies and their plasticity are little known. We aim to document the ability of young grass seedlings to adjust their root system architecture, root morphology and biomass allocation to roots to promote water uptake and survival under progressive drought. Methods Seedlings growing in columns filled with sand and exposed to drought or well-watered controls were repeatedly harvested for determination of biomass fractions, root length, −architecture and-morphology in a greenhouse experiment. Allometric scaling exponents and standardised major axis regression were used to investigate allocation patterns. Results Young seedlings were able to sustain leaf turgor and functions during eight weeks of progressive drought through phenotypic plasticity of the primary root system producing deeper and simpler roots. Biomass allocation to roots decreased or did not respond, and other components of root morphology showed only moderate plasticity. Conclusion Our results suggest that morphological and architectural plasticity of the primary root system may well be key features for dehydration avoidance and survival in grass seedlings under moderate drought when allocation of biomass to roots and development of secondary roots are constrained.
Biodiversity Information Science and Standards
Biodiversity data infrastructures are fundamental to halting the ongoing loss of species and habi... more Biodiversity data infrastructures are fundamental to halting the ongoing loss of species and habitats. Here we provide an overview of the national biodiversity data infrastructure developed and implemented in Norway by The Norwegian Biodiversity Information Centre (NBIC). Key elements and properties of this infrastructure are highlighted and directions for future development are outlined. The overarching objective for the infrastructure is to make data on habitats and species in Norway available for policy and decision makers, researchers and the general public. Here we will focus on data on species and their distribution. The infrastructure is built as a modular system but with a high level of integration between the components. NBIC has the main responsibility for developing and managing the infrastructure in collaboration with natural history museums, research organizations, private companies and non-governmental organizations (NGOs), including the Norwegian node of the Global Bi...
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Papers by Knut Anders Hovstad