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Impacts of savanna trees on forage quality for a large African herbivore

Recently, cover of large trees in African savannas has rapidly declined due to elephant pressure, frequent fires and charcoal production. The reduction in large trees could have consequences for large herbivores through a change in forage quality. In Tarangire National Park, in Northern Tanzania, we...

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Detalles Bibliográficos
Autores principales: Ludwig, Fulco, De Kroon, Hans, Prins, Herbert H. T.
Formato: Texto
Lenguaje:English
Publicado: Springer-Verlag 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2270359/
https://www.ncbi.nlm.nih.gov/pubmed/18309522
http://dx.doi.org/10.1007/s00442-007-0878-9
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author Ludwig, Fulco
De Kroon, Hans
Prins, Herbert H. T.
author_facet Ludwig, Fulco
De Kroon, Hans
Prins, Herbert H. T.
author_sort Ludwig, Fulco
collection PubMed
description Recently, cover of large trees in African savannas has rapidly declined due to elephant pressure, frequent fires and charcoal production. The reduction in large trees could have consequences for large herbivores through a change in forage quality. In Tarangire National Park, in Northern Tanzania, we studied the impact of large savanna trees on forage quality for wildebeest by collecting samples of dominant grass species in open grassland and under and around large Acacia tortilis trees. Grasses growing under trees had a much higher forage quality than grasses from the open field indicated by a more favourable leaf/stem ratio and higher protein and lower fibre concentrations. Analysing the grass leaf data with a linear programming model indicated that large savanna trees could be essential for the survival of wildebeest, the dominant herbivore in Tarangire. Due to the high fibre content and low nutrient and protein concentrations of grasses from the open field, maximum fibre intake is reached before nutrient requirements are satisfied. All requirements can only be satisfied by combining forage from open grassland with either forage from under or around tree canopies. Forage quality was also higher around dead trees than in the open field. So forage quality does not reduce immediately after trees die which explains why negative effects of reduced tree numbers probably go initially unnoticed. In conclusion our results suggest that continued destruction of large trees could affect future numbers of large herbivores in African savannas and better protection of large trees is probably necessary to sustain high animal densities in these ecosystems.
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spelling pubmed-22703592008-03-21 Impacts of savanna trees on forage quality for a large African herbivore Ludwig, Fulco De Kroon, Hans Prins, Herbert H. T. Oecologia Plant Animal Interactions - Original Paper Recently, cover of large trees in African savannas has rapidly declined due to elephant pressure, frequent fires and charcoal production. The reduction in large trees could have consequences for large herbivores through a change in forage quality. In Tarangire National Park, in Northern Tanzania, we studied the impact of large savanna trees on forage quality for wildebeest by collecting samples of dominant grass species in open grassland and under and around large Acacia tortilis trees. Grasses growing under trees had a much higher forage quality than grasses from the open field indicated by a more favourable leaf/stem ratio and higher protein and lower fibre concentrations. Analysing the grass leaf data with a linear programming model indicated that large savanna trees could be essential for the survival of wildebeest, the dominant herbivore in Tarangire. Due to the high fibre content and low nutrient and protein concentrations of grasses from the open field, maximum fibre intake is reached before nutrient requirements are satisfied. All requirements can only be satisfied by combining forage from open grassland with either forage from under or around tree canopies. Forage quality was also higher around dead trees than in the open field. So forage quality does not reduce immediately after trees die which explains why negative effects of reduced tree numbers probably go initially unnoticed. In conclusion our results suggest that continued destruction of large trees could affect future numbers of large herbivores in African savannas and better protection of large trees is probably necessary to sustain high animal densities in these ecosystems. Springer-Verlag 2008-02-29 2008-03 /pmc/articles/PMC2270359/ /pubmed/18309522 http://dx.doi.org/10.1007/s00442-007-0878-9 Text en © The Author(s) 2008
spellingShingle Plant Animal Interactions - Original Paper
Ludwig, Fulco
De Kroon, Hans
Prins, Herbert H. T.
Impacts of savanna trees on forage quality for a large African herbivore
title Impacts of savanna trees on forage quality for a large African herbivore
title_full Impacts of savanna trees on forage quality for a large African herbivore
title_fullStr Impacts of savanna trees on forage quality for a large African herbivore
title_full_unstemmed Impacts of savanna trees on forage quality for a large African herbivore
title_short Impacts of savanna trees on forage quality for a large African herbivore
title_sort impacts of savanna trees on forage quality for a large african herbivore
topic Plant Animal Interactions - Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2270359/
https://www.ncbi.nlm.nih.gov/pubmed/18309522
http://dx.doi.org/10.1007/s00442-007-0878-9
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