Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores
Understanding the functional response of species is important in comprehending the species’ population dynamics and the functioning of multi-species assemblages. A Type II functional response, where instantaneous intake rate increases asymptotically with sward biomass, is thought to be common in gra...
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ftunivwagenin:oai:library.wur.nl:wurpubs/407728 2024-02-04T09:59:21+01:00 Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores Heuermann, N. van Langevelde, F. van Wieren, S.E. Prins, H.H.T. 2011 application/pdf https://research.wur.nl/en/publications/increased-searching-and-handling-effort-in-tall-swards-lead-to-a- https://doi.org/10.1007/s00442-010-1894-8 en eng https://edepot.wur.nl/175164 https://research.wur.nl/en/publications/increased-searching-and-handling-effort-in-tall-swards-lead-to-a- doi:10.1007/s00442-010-1894-8 info:eu-repo/semantics/openAccess Wageningen University & Research Oecologia 166 (2011) 3 ISSN: 0029-8549 biomass density foraging behavior grass stems height instantaneous intake rate mammalian herbivores models quality serengeti info:eu-repo/semantics/article Article/Letter to editor info:eu-repo/semantics/publishedVersion 2011 ftunivwagenin https://doi.org/10.1007/s00442-010-1894-8 2024-01-10T23:22:04Z Understanding the functional response of species is important in comprehending the species’ population dynamics and the functioning of multi-species assemblages. A Type II functional response, where instantaneous intake rate increases asymptotically with sward biomass, is thought to be common in grazers. However, at tall, dense swards, food intake might decline due to mechanical limitations or if animals selectively forage on the most nutritious parts of a sward, leading to a Type IV functional response, especially for smaller herbivores. We tested the predictions that bite mass, cropping time, swallowing time and searching time increase, and bite rate decreases with increasing grass biomass for different-sized Canada geese (Branta canadensis) foraging on grass swards. Bite mass indeed showed an increasing asymptotic relationship with grass biomass. At high biomass, difficulties in handling long leaves and in locating bites were responsible for increasing cropping, swallowing, and searching times. Constant bite mass and decreasing bite rate caused the intake rate to decrease at high sward biomass after reaching an optimum, leading to a Type IV functional response. Grazer body mass affected maximum bite mass and intake rate, but did not change the shape of the functional response. As grass nutrient contents are usually highest in short swards, this Type IV functional response in geese leads to an intake rate that is maximised in these swards. The lower grass biomass at which intake rate was maximised allows resource partitioning between different-sized grazers. We argue that this Type IV functional response is of more importance than previously thought. Article in Journal/Newspaper Branta canadensis Wageningen UR (University & Research Centre): Digital Library Canada Oecologia 166 3 659 669 |
institution |
Open Polar |
collection |
Wageningen UR (University & Research Centre): Digital Library |
op_collection_id |
ftunivwagenin |
language |
English |
topic |
biomass density foraging behavior grass stems height instantaneous intake rate mammalian herbivores models quality serengeti |
spellingShingle |
biomass density foraging behavior grass stems height instantaneous intake rate mammalian herbivores models quality serengeti Heuermann, N. van Langevelde, F. van Wieren, S.E. Prins, H.H.T. Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores |
topic_facet |
biomass density foraging behavior grass stems height instantaneous intake rate mammalian herbivores models quality serengeti |
description |
Understanding the functional response of species is important in comprehending the species’ population dynamics and the functioning of multi-species assemblages. A Type II functional response, where instantaneous intake rate increases asymptotically with sward biomass, is thought to be common in grazers. However, at tall, dense swards, food intake might decline due to mechanical limitations or if animals selectively forage on the most nutritious parts of a sward, leading to a Type IV functional response, especially for smaller herbivores. We tested the predictions that bite mass, cropping time, swallowing time and searching time increase, and bite rate decreases with increasing grass biomass for different-sized Canada geese (Branta canadensis) foraging on grass swards. Bite mass indeed showed an increasing asymptotic relationship with grass biomass. At high biomass, difficulties in handling long leaves and in locating bites were responsible for increasing cropping, swallowing, and searching times. Constant bite mass and decreasing bite rate caused the intake rate to decrease at high sward biomass after reaching an optimum, leading to a Type IV functional response. Grazer body mass affected maximum bite mass and intake rate, but did not change the shape of the functional response. As grass nutrient contents are usually highest in short swards, this Type IV functional response in geese leads to an intake rate that is maximised in these swards. The lower grass biomass at which intake rate was maximised allows resource partitioning between different-sized grazers. We argue that this Type IV functional response is of more importance than previously thought. |
format |
Article in Journal/Newspaper |
author |
Heuermann, N. van Langevelde, F. van Wieren, S.E. Prins, H.H.T. |
author_facet |
Heuermann, N. van Langevelde, F. van Wieren, S.E. Prins, H.H.T. |
author_sort |
Heuermann, N. |
title |
Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores |
title_short |
Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores |
title_full |
Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores |
title_fullStr |
Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores |
title_full_unstemmed |
Increased searching and handling effort in tall swards lead to a Type IV functional response in small grazing herbivores |
title_sort |
increased searching and handling effort in tall swards lead to a type iv functional response in small grazing herbivores |
publishDate |
2011 |
url |
https://research.wur.nl/en/publications/increased-searching-and-handling-effort-in-tall-swards-lead-to-a- https://doi.org/10.1007/s00442-010-1894-8 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Branta canadensis |
genre_facet |
Branta canadensis |
op_source |
Oecologia 166 (2011) 3 ISSN: 0029-8549 |
op_relation |
https://edepot.wur.nl/175164 https://research.wur.nl/en/publications/increased-searching-and-handling-effort-in-tall-swards-lead-to-a- doi:10.1007/s00442-010-1894-8 |
op_rights |
info:eu-repo/semantics/openAccess Wageningen University & Research |
op_doi |
https://doi.org/10.1007/s00442-010-1894-8 |
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Oecologia |
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166 |
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3 |
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659 |
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669 |
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