Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem
Herbivores may increase or decrease aboveground plant productivity depending on factors such as herbivore density and habitat productivity. The grazing optimization hypothesis predicts a peak in plant production at intermediate herbivore densities, but has rarely been tested experimentally in an alp...
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ftoslouniv:oai:www.duo.uio.no:10852/57072 2023-05-15T14:14:26+02:00 Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem Austrheim, Gunnar Speed, James David Mervyn Martinsen, Vegard Mulder, Jan Mysterud, Atle 2015-01-20T13:42:46Z http://hdl.handle.net/10852/57072 http://urn.nb.no/URN:NBN:no-59843 https://doi.org/10.1657/1938-4246-46.3.535 EN eng Institute of Arctic and Alpine Research http://urn.nb.no/URN:NBN:no-59843 Austrheim, Gunnar Speed, James David Mervyn Martinsen, Vegard Mulder, Jan Mysterud, Atle . Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem. Arctic, Antarctic and Alpine research. 2014, 46(3), 535-541 http://hdl.handle.net/10852/57072 1202538 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Arctic, Antarctic and Alpine research&rft.volume=46&rft.spage=535&rft.date=2014 Arctic, Antarctic and Alpine research 46 3 535 541 http://dx.doi.org/10.1657/1938-4246-46.3.535 URN:NBN:no-59843 Fulltext https://www.duo.uio.no/bitstream/handle/10852/57072/2/1938-4246-44.1.6785439.pdf 1523-0430 Journal article Tidsskriftartikkel Peer reviewed PublishedVersion 2015 ftoslouniv https://doi.org/10.1657/1938-4246-46.3.535 2020-06-21T08:50:59Z Herbivores may increase or decrease aboveground plant productivity depending on factors such as herbivore density and habitat productivity. The grazing optimization hypothesis predicts a peak in plant production at intermediate herbivore densities, but has rarely been tested experimentally in an alpine field setting. In an experimental design with three densities of sheep (high, low, and no sheep), we harvested aboveground plant biomass in alpine grasslands prior to treatment and after five years of grazing. Biomass of vascular plants decreased at high sheep density, and marginally increased at low sheep density. The ungrazed treatment was found to be intermediate. Companion studies conducted at the same site suggest, (1) that changes in soil N-mineralization and plant community patterns are contributing to the herbivore-induced effects on plant productivity in alpine grasslands, (2) that herbivore-driven changes in plant productivity feed into the future performance for the herbivore as the marginal increase in productivity at low density corresponds with a temporal increase in lamb growth. Our study provides experimental evidence for a nonlinear effect of increased grazing on plant productivity as predicted by the grazing optimization hypothesis. This has important repercussions for ecosystem function and management, as it demonstrates how herbivore density can either increase or decrease ecosystem productivity over time. © University of Colorado at Boulder, Institute of Arctic and Alpine Research Article in Journal/Newspaper Antarctic and Alpine Research Arctic Arctic Institute of Arctic and Alpine Research Universitet i Oslo: Digitale utgivelser ved UiO (DUO) Arctic Arctic, Antarctic, and Alpine Research 46 3 535 541 |
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Open Polar |
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Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
op_collection_id |
ftoslouniv |
language |
English |
description |
Herbivores may increase or decrease aboveground plant productivity depending on factors such as herbivore density and habitat productivity. The grazing optimization hypothesis predicts a peak in plant production at intermediate herbivore densities, but has rarely been tested experimentally in an alpine field setting. In an experimental design with three densities of sheep (high, low, and no sheep), we harvested aboveground plant biomass in alpine grasslands prior to treatment and after five years of grazing. Biomass of vascular plants decreased at high sheep density, and marginally increased at low sheep density. The ungrazed treatment was found to be intermediate. Companion studies conducted at the same site suggest, (1) that changes in soil N-mineralization and plant community patterns are contributing to the herbivore-induced effects on plant productivity in alpine grasslands, (2) that herbivore-driven changes in plant productivity feed into the future performance for the herbivore as the marginal increase in productivity at low density corresponds with a temporal increase in lamb growth. Our study provides experimental evidence for a nonlinear effect of increased grazing on plant productivity as predicted by the grazing optimization hypothesis. This has important repercussions for ecosystem function and management, as it demonstrates how herbivore density can either increase or decrease ecosystem productivity over time. © University of Colorado at Boulder, Institute of Arctic and Alpine Research |
format |
Article in Journal/Newspaper |
author |
Austrheim, Gunnar Speed, James David Mervyn Martinsen, Vegard Mulder, Jan Mysterud, Atle |
spellingShingle |
Austrheim, Gunnar Speed, James David Mervyn Martinsen, Vegard Mulder, Jan Mysterud, Atle Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
author_facet |
Austrheim, Gunnar Speed, James David Mervyn Martinsen, Vegard Mulder, Jan Mysterud, Atle |
author_sort |
Austrheim, Gunnar |
title |
Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
title_short |
Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
title_full |
Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
title_fullStr |
Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
title_full_unstemmed |
Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
title_sort |
experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem |
publisher |
Institute of Arctic and Alpine Research |
publishDate |
2015 |
url |
http://hdl.handle.net/10852/57072 http://urn.nb.no/URN:NBN:no-59843 https://doi.org/10.1657/1938-4246-46.3.535 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Antarctic and Alpine Research Arctic Arctic Institute of Arctic and Alpine Research |
genre_facet |
Antarctic and Alpine Research Arctic Arctic Institute of Arctic and Alpine Research |
op_source |
1523-0430 |
op_relation |
http://urn.nb.no/URN:NBN:no-59843 Austrheim, Gunnar Speed, James David Mervyn Martinsen, Vegard Mulder, Jan Mysterud, Atle . Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem. Arctic, Antarctic and Alpine research. 2014, 46(3), 535-541 http://hdl.handle.net/10852/57072 1202538 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Arctic, Antarctic and Alpine research&rft.volume=46&rft.spage=535&rft.date=2014 Arctic, Antarctic and Alpine research 46 3 535 541 http://dx.doi.org/10.1657/1938-4246-46.3.535 URN:NBN:no-59843 Fulltext https://www.duo.uio.no/bitstream/handle/10852/57072/2/1938-4246-44.1.6785439.pdf |
op_doi |
https://doi.org/10.1657/1938-4246-46.3.535 |
container_title |
Arctic, Antarctic, and Alpine Research |
container_volume |
46 |
container_issue |
3 |
container_start_page |
535 |
op_container_end_page |
541 |
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1766286897413357568 |