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Effects of herbivores and standing crop on plant species and functional trait composition in Beringia
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Research Interests: Environmental Science, Arctic (Ecology), Arctic, SNOW, The Arctic, and 4 moreBoreal, Latitude, Taiga, and North Pole
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Produced by the ICSU/WMO Joint Committee for IPY 2007–2008 By: Ian Allison and Michel Beland (Co-Chairs), Keith Alverson, Robin Bell, David Carlson, Kjell Danell, Cynan Ellis-Evans, Eberhard Fahrbach, Edith Fanta, Yoshiyuki Fujii, Gisbert... more
Produced by the ICSU/WMO Joint Committee for IPY 2007–2008 By: Ian Allison and Michel Beland (Co-Chairs), Keith Alverson, Robin Bell, David Carlson, Kjell Danell, Cynan Ellis-Evans, Eberhard Fahrbach, Edith Fanta, Yoshiyuki Fujii, Gisbert Gilbertson, Leah Goldfarb, Grete Hovelsrud-Broda, Johannes Huber, Vladimir Kotlyakov, Igor Krupnik, Jeronimo Lopez-Martinez, Tillmann Mohr, Dahe Qin, Volker Rachold, Chris Rapley, Odd Rogne, Eduard Sarukhanian, Colin Summerhayes, Cunde Xiao
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The bite diameter selection by moose in relation to twig quality on four phenotypes of Scots pine was studied on the basis of a field cafeteria experiment. Comparison of twig quality was made among: 1) phenotypes, 2) different twig... more
The bite diameter selection by moose in relation to twig quality on four phenotypes of Scots pine was studied on the basis of a field cafeteria experiment. Comparison of twig quality was made among: 1) phenotypes, 2) different twig diameters, and 3) mean moose bite diameters. Chemical and morphological analyses of the trees indicated that twig fibre and tree/shoot size strongly affected moose bite diameter choice. Sight and chewing sensation are suggested to be the main browsing strategies used by moose. Moose adjusted the bite diameter among phenotypes on the criterion of similar food quality. The factors involved may play a multiple role in affecting moose foraging. Quantitative features of trees had no significant effects on moose bite diameter selection.
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The muskrat Ondatra zibethicus is one of the semi‐aquatic rodents that has been introduced into many areas of the world. It is regarded as a most successful vertebrate invader. In northwestern Europe, it was introduced to Finland in 1919... more
The muskrat Ondatra zibethicus is one of the semi‐aquatic rodents that has been introduced into many areas of the world. It is regarded as a most successful vertebrate invader. In northwestern Europe, it was introduced to Finland in 1919 and to the Kola Peninsula in 1931. From these areas, it spread ‘naturally’ to Sweden and Norway, respectively. Here the history of the introduction, dispersal, population development, impact on plant communities, impact on man, and indirect and direct effects on other animals in northwestern Europe are reviewed. The biological features of the muskrat are discussed in relation to the attributes of other vertebrates that are regarded as successful invaders.
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A laser system and techniques which compensate for laser fluence drop off or losses of irradiation as an ablating laser beam is traversed on a curved surface (e.g., on corneal tissue). The disclosed ablating laser system and techniques... more
A laser system and techniques which compensate for laser fluence drop off or losses of irradiation as an ablating laser beam is traversed on a curved surface (e.g., on corneal tissue). The disclosed ablating laser system and techniques compensate for fluence differentials from pulse-to-pulse by adjusting an appropriate parameter of a laser beam. In the preferred embodiment, the number of pulses imparted in the periphery, the size or shape of the ablating laser beam is adjusted with, e.g., a variable aperture placed in the beam delivery path, by changing a magnification of relay optics in the beam delivery path, or by increasing a number of ablation spots in peripheral portions of an ablation zone as compared with the number of ablation spots in a central portion of the ablation zone. The fluence is compensated for using empirically measured or theoretical fluence correction factors given the angle of the laser beam, size and shape of the ablation spot, etc. In addition to magnification adjustment, the present invention also employs the technique of changing the size of the aperture that is imaged o the eye to provide uniform energy density (i.e., fluence) throughout the entire area of the irradiation site. These techniques are used independently or in conjunction to reshape the curvature of the eye to correct myopia, hyperopia, astigmatism or combinations thereof.
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Under the implementation of the Convention on Biological Diversity, a special emphasis has been put on an integrated ecosystem approach. Some of the "Malawi principles" state that management objectives are a matter of societal... more
Under the implementation of the Convention on Biological Diversity, a special emphasis has been put on an integrated ecosystem approach. Some of the "Malawi principles" state that management objectives are a matter of societal choice, and that management should be decentralized to the lowest appropriate level. A key feature of the ecosystem approach includes conservation of ecosystem structure and function on a long term basis, while seeking an appropriate balance between conservation and use of biodiversity. The role of moose in the ecosystem and how the Malawi principles can be adopted in moose management were a focus of the 5th International Moose Symposium. All invited speakers and session chairs were asked to provide a brief summary of how they considered the Malawi principles to relate to the topic of their respective papers or sessions at the Symposium. Those summaries are given in this paper.
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... John Pastor1 and Kjell Danell2 ... bouts to meet daily requirements of 5 – 10 kg per day (Belovsky and Jordan 1978, Renecker and Hudson 1986, Renecker and ... of leaves such that total leaf production during the growing season... more
... John Pastor1 and Kjell Danell2 ... bouts to meet daily requirements of 5 – 10 kg per day (Belovsky and Jordan 1978, Renecker and Hudson 1986, Renecker and ... of leaves such that total leaf production during the growing season (removed leaves plus regrown leaves) did not differ ...
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... In modern managed forests, bark beetles often consume most of the cambium during the first sum-mer after the tree's death. In slow-growing spruce stands species that are adapted to later stages of decay can fi nd unscathed... more
... In modern managed forests, bark beetles often consume most of the cambium during the first sum-mer after the tree's death. In slow-growing spruce stands species that are adapted to later stages of decay can fi nd unscathed parts of the stem years after the tree has died. ...
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Research Interests: Botany, Biology, Biological Sciences, Resource use, Egg Laying, and 8 moreLarva, Egg, Polar Biology, Willow, Salicaceae, Host Plant, Shoot, and Woody plant
Leaf damage decreases the quality of birch foliage for insects, but damage to twigs during winter may have opposite effects: insect densities were higher on birches browsed by moose than on unbrowsed trees. We tested whether the... more
Leaf damage decreases the quality of birch foliage for insects, but damage to twigs during winter may have opposite effects: insect densities were higher on birches browsed by moose than on unbrowsed trees. We tested whether the performance of Epirrita autumnata larvae was increased by simulated browsing during winter. We found no significant correlation between browsing intensity and any of the indices of Epirrita performance. Pupal weights and larval survival were slightly higher on birches artificially browsed 0 to 2 yr earlier than on control trees, but the differences between treatments were not significant. Power analyses of our experiments showed that strong effects on Epirrita performance via browsing-induced changes in birch quality were not probable. Although simulated browsing affected Epirrita performance only slightly, we found a large difference in leaf quality between upper and lower canopy. Epirrita pupal weights were about 25% higher on the top than on the basal part of the canopy.
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The muskrat (Ondatra zibethica (L.)) utilizes emergent hydrophytes both for housebuilding and for food. The impact of these activities on stands of Equisetum fluviatile L. in a northern Swedish lake was investigated. The areas of open... more
The muskrat (Ondatra zibethica (L.)) utilizes emergent hydrophytes both for housebuilding and for food. The impact of these activities on stands of Equisetum fluviatile L. in a northern Swedish lake was investigated. The areas of open water created by the muskrats were estimated from infrared air photographs, taken in July, on three occasions during a five-year period. During the first
Research Interests: Biology, Ecology, Medicine, Colonization, Population, and 3 moreAquatic Vegetation, Oecologia, and Infrared
Ungulate browsing can have a strong effect on ecological processes by affecting plant community structure and composition, with cascading effects on nutrient cycling and animal communities. However, in the absence of direct observations... more
Ungulate browsing can have a strong effect on ecological processes by affecting plant community structure and composition, with cascading effects on nutrient cycling and animal communities. However, in the absence of direct observations of foraging, species‐specific foraging behaviours are difficult to quantify. We therefore know relatively little about foraging competition and species‐specific browsing patterns in systems with several browsers. However, during browsing, a small amount of saliva containing buccal cells is deposited at the bite site, providing a source of environmental DNA (eDNA) that can be used for species identification. Here, we describe extraction and PCR protocols for a browser species diagnostic kit. Species‐specific primers for mitochondrial DNA were optimized and validated using twigs browsed by captive animals. A time series showed that about 50% of the samples will amplify up to 12 weeks after the browsing event and that some samples amplify up to 24 weeks...
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... The shallow sedge belt was most utilized in May and June, but was to a large extent abandoned later on, when the deeper water horsetail belt became well stocked. ... I am further indebt-ed to L.-O. Eriksson, A. Gothberg, V. Marcstrom,... more
... The shallow sedge belt was most utilized in May and June, but was to a large extent abandoned later on, when the deeper water horsetail belt became well stocked. ... I am further indebt-ed to L.-O. Eriksson, A. Gothberg, V. Marcstrom, K. Sjoberg, and T. Sorlin for 540 J. Wildl. ...
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... 60 C) is 120-140 days (Johannessen ... This belt is succeeded outwards by extensive stands of Equisetumfluviatile.Within the Equisetum belt there are numerous small clones of bulrush (Schoenoplectus lacustris (L.) Palla) and other... more
... 60 C) is 120-140 days (Johannessen ... This belt is succeeded outwards by extensive stands of Equisetumfluviatile.Within the Equisetum belt there are numerous small clones of bulrush (Schoenoplectus lacustris (L.) Palla) and other plant species such as Nuphar lutea, the least ...
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... INTRODUCTION An analysis of Canadian fur trade statistics revealed a strongly-marked 'cyclic' fluctuation in the annual numbers of muskrats (Ondatra zibethica (L.)) harvested, with a mean periodicity of about 10... more
... INTRODUCTION An analysis of Canadian fur trade statistics revealed a strongly-marked 'cyclic' fluctuation in the annual numbers of muskrats (Ondatra zibethica (L.)) harvested, with a mean periodicity of about 10 years (Elton & Nicholson 1942). ...
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Introduction: Reflecting on IPY Planning Themes During the planning phase of IPY 2007–2008, a number of major themes emerged from the communitybased consultation planning. In 2004, the ICSU Planning Group identified six major research... more
Introduction: Reflecting on IPY Planning Themes During the planning phase of IPY 2007–2008, a number of major themes emerged from the communitybased consultation planning. In 2004, the ICSU Planning Group identified six major research themes outlined in the "Framework" document (Rapley et al., 2004; Chapter 1.3). These major IPY research themes were: (1) To determine the present environmental status of the polar regions by quantifying their spatial and temporal variability. (2) To quantify and understand past and present environmental and human change in the polar regions in order to improve predictions. (3) To advance our understanding of polar-global teleconnections on all scales and of the processes controlling these interactions. (4) To investigate the unknowns at the frontiers of science in the polar regions. (5) To use the unique vantage point of the polar regions to develop and enhance observatories studying the Earth’s inner core, the Earth’s magnetic field, geospace, the Sun and beyond. (6) To investigate the cultural, historical and social processes, which shape the resilience and sustainability of circumpolar human societies, and to identify their unique contributions to global cultural diversity and citizenship. This summary reviews the early ideas and findings from each of the themes. Our objective is to take stock of what the IPY scientific community has learned to date, that is, by the official closing of IPY 2007–2008 at the IPY Open Science Conference in Oslo in June 2010 (Chapter 5.6). The previous chapters outlined what happened during IPY. Here, we will focus on the general achievements of the IPY science program. This summary is deliberately written to avoid referring to individual IPY projects, program names or specific activities that have been amply covered in other sections of this volume (Part 2; Part 3; Chapters 5.2, 5.3, and 5.4). As is known from previous IPY/IGY efforts (Chapter 1.1), the major insights will take a substantial time to emerge. Given the initial stage of analysis and interpretation of much of the IPY data, this summary is neither comprehensive nor complete. Also, it uses a limited number of references, since the main literature based on the IPY results has not emerged yet. Many preliminary results (at the time of this writing) were only available from the abstracts of papers presented at the Oslo IPY Science Conference in June 2010 (e.g., Bell et al., 2010a; Ferracioli et al., 2010; Wiens et al., 2010).1 Nonetheless, this chapter should be viewed as a first glimpse of the advances in our inter-disciplinary (and often, cross-disciplinary) understanding of the processes and linkages in the polar regions. For decades, the data collected during IPY 2007–2008 will support new scientific insights and advances.
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Spines in plants have evolved to reduce mammalian herbivory, and their main function may be to protect twigs more than photosynthetic tissue. Type and frequency of spines vary at different scales. We hypothesised that different types of... more
Spines in plants have evolved to reduce mammalian herbivory, and their main function may be to protect twigs more than photosynthetic tissue. Type and frequency of spines vary at different scales. We hypothesised that different types of spines affect animal foraging through different mechanisms. We studied feeding behaviour by twig-browsing goats in relation to two types of spines of Acacia tortilis using experimental manipulation of the occurrence of spines. Feeding time, number of biting actions, number and diameter of bites on trees (post-trial) and total intake were recorded. The removal of either long straight spines or short hooked spines resulted in no feeding responses by goats. The removal of both types of spines tended to increase feeding time resulting in more and larger bites with larger bite diameters and in increased total intake and utilisation compared to control branches. The removal of spines had no effects on feeding rate, expressed as biting actions per minute, number of twigs bitten per minute or intake rate (grams per minute). Both types of spines reduced total intake and utilisation of browse, but the functional mechanisms were different with the long straight spines mainly influencing bite size and short hooked spines mainly affecting number of bites. Keywords: Acacia tortilis , browsing, feeding rate, functional response, plant defence African Journal of Range & Forage Science 2012, 29(1): 37–41
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Effects of herbivores and standing crop on plant species and functional trait composition in Beringia
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K. Danell (kjell.danell@szooek.slu.se) and]. P. Ball, Dept of Animal Ecology, Swedish Univ. of Agricultural Sciences, SE-901 83 Urnea, Sweden. ?A. Hofgaard, Climate Impacts Research Centre (CIRC), Box 62, SE-981 07Abisko, Sweden, and Dept... more
K. Danell (kjell.danell@szooek.slu.se) and]. P. Ball, Dept of Animal Ecology, Swedish Univ. of Agricultural Sciences, SE-901 83 Urnea, Sweden. ?A. Hofgaard, Climate Impacts Research Centre (CIRC), Box 62, SE-981 07Abisko, Sweden, and Dept of Animal Ecology, Swedish Univ. of Agricultural Sciences, SE-901 83 Ume?, Sweden. -TV. Callaghan, Abisko Scientific Research Station, Box 62, SE-981 07 Abisko, Sweden, and Sheffield Centre for Artic Ecology, 26 Taptonville Road, Sheffield, U.K. S10 5BR.
Research Interests: Geography and Agriculture
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Preface A. Hofgaard and T. V. Callaghan Scenarios for animal responses to global change in Europe's cold regions: an introduction K. Danell, A. Hofgaard, T. V. Callaghan and J. P. Ball Spatial responses of animals to climate change... more
Preface A. Hofgaard and T. V. Callaghan Scenarios for animal responses to global change in Europe's cold regions: an introduction K. Danell, A. Hofgaard, T. V. Callaghan and J. P. Ball Spatial responses of animals to climate change during the Quaternary R. H. W. Bradshaw Ecological characteristics of mammals in the biomes of Europe K. Danell Latitudinal gradients in species richness in northern areas: some exceptional pattern J. Kouki Impacts of climate warming on artic aphids: a comparative analysis J. S. Bale Bark beetles in a changing environment K. Heliovaara and M. Peltonen Climate and the population dynamics of two insect outbreak species in the north H. Bylund Climatic change and insect outbreaks in boreal forests: the role of winter temperatures S. Neuvonen, P. Niemela and T. Virtanen The direct and indirect effects of enhanced UV-B on the moth caterpillar Epirrita autumnata N. Buck and T. V. Callaghan Enhanced UV-B radiation and herbivory D. Gwynn-Jones Responses to def...
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Research Interests: Botany, Biology, Ecology, Nutrient, Deciduous, and 7 moreSubspecies, Betula Pendula, Herbivore, Shoot, Tree line, Betulaceae, and Betula pubescens
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The distribution of plant species and functional traits in alpine and arctic environments are determined by abiotic conditions, but also by biotic interactions. In this thesis, I investigate interactions among plants and herbivory effects... more
The distribution of plant species and functional traits in alpine and arctic environments are determined by abiotic conditions, but also by biotic interactions. In this thesis, I investigate interactions among plants and herbivory effects on plant community composition and plant functional traits in three different regions: Swedish Lapland, Beringia (USA/Russia) and Finnmark (Norway). Reindeer grazing was found to be extensive in southern Lapland and had limited effects on plant community composition and seedling germination. However, reindeer presence was found to influence plant functional traits, particularly in the subalpine birch forest. Tall herbs were lower and had lower SLA when reindeer were present, while small herbs showed an opposite pattern. The contrasting effects on the two herb groups are probably explained by a competitive release for small herbs when the tall herbs are suppressed by reindeer. Rodents had the largest relative impact on plant community composition in southern Lapland and this is consistent with the study from Finnmark, where rodents heavily affected dwarf shrubs on predator-free islands. With no predators present, vole densities increased profoundly and almost depleted some dwarf shrub species. These results support the idea that small mammals in arctic and alpine tundra are controlled by predators (i.e. top-down). However, a decrease in the nutritional quality in a sedge after defoliation gives support for the idea that small mammals are regulated by plant quality (i.e. bottom-up). In Beringia, small and large herbivores differed in the relation to plant community composition, since large herbivores were related to species richness and small herbivores were related to plant abundance. Plant functional traits were related only to large herbivores and standing crop of vascular plants.
Research Interests: Biology, Ecology, Biotic interactions, Herbivory, Tundra, and 3 morePlant Community, Herbivore, and Shrub
3 e-mail: john.ball@szooek.slu.se ABSTRACT: Although hunters cause more than 80% of moose mortality in some geographic areas, quantitative studies of how moose attempt to escape humans are surprisingly rare. We experimen- tally disturbed... more
3 e-mail: john.ball@szooek.slu.se ABSTRACT: Although hunters cause more than 80% of moose mortality in some geographic areas, quantitative studies of how moose attempt to escape humans are surprisingly rare. We experimen- tally disturbed radio-collared moose of known age and of both sexes to study escape behaviour from humans. We found that larger groups of moose made fewer stops between being disturbed and settling down, and that larger groups exhibited a longer path length before quieting. We detected no significant effect of age (a potential measure of survival rate) on escape behaviour. The escape path of males was significantly longer than females even though the linear distance from the site of disturbance to the location where the moose settled down was not significantly different between the sexes. Overall, the escape path of males from the site of disturbance to where they settled down was significantly more tortuous than that of females. Although males are the preferred prey of hunters, the differences in escape behaviour between the sexes also may contribute to why males are more frequently killed by hunters. Thus, in areas with heavy hunting pressure, hunters may be acting as a selective force that favours animals that immediately run away after disturbance by humans. Finally, published evaluations of the use of hunter observations to index moose populations have often reported that considering the size of a hunting group is necessary to improve the accuracy of those data; our analysis suggests an explanation - differences in escape behaviour between the sexes. ALCES VOL. 40: 123-131 (2004)