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Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation

In savannas, the tree–grass balance is governed by water, nutrients, fire and herbivory, and their interactions. We studied the hypothesis that herbivores indirectly affect vegetation structure by changing the availability of soil nutrients, which, in turn, alters the competition between trees and g...

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Autores principales: van der Waal, Cornelis, Kool, Ada, Meijer, Seline S., Kohi, Edward, Heitkönig, Ignas M. A., de Boer, Willem F., van Langevelde, Frank, Grant, Rina C., Peel, Mike J. S., Slotow, Rob, de Knegt, Henrik J., Prins, Herbert H. T., de Kroon, Hans
Formato: Texto
Lenguaje:English
Publicado: Springer-Verlag 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057003/
https://www.ncbi.nlm.nih.gov/pubmed/21225433
http://dx.doi.org/10.1007/s00442-010-1899-3
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author van der Waal, Cornelis
Kool, Ada
Meijer, Seline S.
Kohi, Edward
Heitkönig, Ignas M. A.
de Boer, Willem F.
van Langevelde, Frank
Grant, Rina C.
Peel, Mike J. S.
Slotow, Rob
de Knegt, Henrik J.
Prins, Herbert H. T.
de Kroon, Hans
author_facet van der Waal, Cornelis
Kool, Ada
Meijer, Seline S.
Kohi, Edward
Heitkönig, Ignas M. A.
de Boer, Willem F.
van Langevelde, Frank
Grant, Rina C.
Peel, Mike J. S.
Slotow, Rob
de Knegt, Henrik J.
Prins, Herbert H. T.
de Kroon, Hans
author_sort van der Waal, Cornelis
collection PubMed
description In savannas, the tree–grass balance is governed by water, nutrients, fire and herbivory, and their interactions. We studied the hypothesis that herbivores indirectly affect vegetation structure by changing the availability of soil nutrients, which, in turn, alters the competition between trees and grasses. Nine abandoned livestock holding-pen areas (kraals), enriched by dung and urine, were contrasted with nearby control sites in a semi-arid savanna. About 40 years after abandonment, kraal sites still showed high soil concentrations of inorganic N, extractable P, K, Ca and Mg compared to controls. Kraals also had a high plant production potential and offered high quality forage. The intense grazing and high herbivore dung and urine deposition rates in kraals fit the accelerated nutrient cycling model described for fertile systems elsewhere. Data of a concurrent experiment also showed that bush-cleared patches resulted in an increase in impala dung deposition, probably because impala preferred open sites to avoid predation. Kraal sites had very low tree densities compared to control sites, thus the high impala dung deposition rates here may be in part driven by the open structure of kraal sites, which may explain the persistence of nutrients in kraals. Experiments indicated that tree seedlings were increasingly constrained when competing with grasses under fertile conditions, which might explain the low tree recruitment observed in kraals. In conclusion, large herbivores may indirectly keep existing nutrient hotspots such as abandoned kraals structurally open by maintaining a high local soil fertility, which, in turn, constrains woody recruitment in a negative feedback loop. The maintenance of nutrient hotspots such as abandoned kraals by herbivores contributes to the structural heterogeneity of nutrient-poor savanna vegetation.
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spelling pubmed-30570032011-04-05 Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation van der Waal, Cornelis Kool, Ada Meijer, Seline S. Kohi, Edward Heitkönig, Ignas M. A. de Boer, Willem F. van Langevelde, Frank Grant, Rina C. Peel, Mike J. S. Slotow, Rob de Knegt, Henrik J. Prins, Herbert H. T. de Kroon, Hans Oecologia Ecosystem ecology - Original Paper In savannas, the tree–grass balance is governed by water, nutrients, fire and herbivory, and their interactions. We studied the hypothesis that herbivores indirectly affect vegetation structure by changing the availability of soil nutrients, which, in turn, alters the competition between trees and grasses. Nine abandoned livestock holding-pen areas (kraals), enriched by dung and urine, were contrasted with nearby control sites in a semi-arid savanna. About 40 years after abandonment, kraal sites still showed high soil concentrations of inorganic N, extractable P, K, Ca and Mg compared to controls. Kraals also had a high plant production potential and offered high quality forage. The intense grazing and high herbivore dung and urine deposition rates in kraals fit the accelerated nutrient cycling model described for fertile systems elsewhere. Data of a concurrent experiment also showed that bush-cleared patches resulted in an increase in impala dung deposition, probably because impala preferred open sites to avoid predation. Kraal sites had very low tree densities compared to control sites, thus the high impala dung deposition rates here may be in part driven by the open structure of kraal sites, which may explain the persistence of nutrients in kraals. Experiments indicated that tree seedlings were increasingly constrained when competing with grasses under fertile conditions, which might explain the low tree recruitment observed in kraals. In conclusion, large herbivores may indirectly keep existing nutrient hotspots such as abandoned kraals structurally open by maintaining a high local soil fertility, which, in turn, constrains woody recruitment in a negative feedback loop. The maintenance of nutrient hotspots such as abandoned kraals by herbivores contributes to the structural heterogeneity of nutrient-poor savanna vegetation. Springer-Verlag 2011-01-12 2011 /pmc/articles/PMC3057003/ /pubmed/21225433 http://dx.doi.org/10.1007/s00442-010-1899-3 Text en © The Author(s) 2011 https://creativecommons.org/licenses/by-nc/4.0/ This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
spellingShingle Ecosystem ecology - Original Paper
van der Waal, Cornelis
Kool, Ada
Meijer, Seline S.
Kohi, Edward
Heitkönig, Ignas M. A.
de Boer, Willem F.
van Langevelde, Frank
Grant, Rina C.
Peel, Mike J. S.
Slotow, Rob
de Knegt, Henrik J.
Prins, Herbert H. T.
de Kroon, Hans
Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
title Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
title_full Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
title_fullStr Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
title_full_unstemmed Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
title_short Large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
title_sort large herbivores may alter vegetation structure of semi-arid savannas through soil nutrient mediation
topic Ecosystem ecology - Original Paper
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3057003/
https://www.ncbi.nlm.nih.gov/pubmed/21225433
http://dx.doi.org/10.1007/s00442-010-1899-3
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