Universität zu Köln

Pfeiffer, Mirjam, Langan, Liam ORCID: 0000-0002-4765-9510, Linstaedter, Anja, Martens, Carola, Gaillard, Camille, Ruppert, Jan C., Higgins, Steven I., Mudongo, Edwin I. and Scheiter, Simon ORCID: 0000-0002-5449-841X (2019). Grazing and aridity reduce perennial grass abundance in semi-arid rangelands - Insights from a trait-based dynamic vegetation model. Ecol. Model., 395. S. 11 - 23. AMSTERDAM: ELSEVIER SCIENCE BV. ISSN 1872-7026

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Abstract

Semi-arid tropical rangelands substantially contribute to livelihoods of subsistence farmers, but are threatened by undesired vegetation shifts due to climate change and overgrazing. Grazing-induced shifts of the grass community composition are often associated with rangeland degradation. To identify sustainable management strategies, a process-based understanding of grass functional diversity and rangeland dynamics is required. We present a new scheme for aDGVM2, a dynamic vegetation model for tropical ecosystems, that distinguishes annual and perennial grasses based on trait trade-offs to improve the representation of rangeland communities. Additionally, the model includes a new scheme that describes selective grazing and grazing effects on grass-layer composition. We tested the new model version for various grazing intensities along a precipitation gradient in South Africa. Mean annual precipitation below 500 mm constrained rangeland productivity and carrying capacity. Increasing grazing intensity reduced rangeland productivity and increased annual grass abundance. Heavy grazing resulted in annual grass dominance. Livestock preferred perennial over annual grasses at low grazing intensities at all except the two driest sites; preference switched to annual grasses at intermediate intensities, and became non-discriminating at high grazing intensities. Rangeland recovery after removal of grazers required 2-15 years. We conclude that management intervention reducing or eliminating grazing pressure during and after stress years is crucial to allow rangeland recovery and avoid permanent degradation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Pfeiffer, Mirjam UNSPECIFIED UNSPECIFIED UNSPECIFIED Langan, Liam UNSPECIFIED orcid.org/0000-0002-4765-9510 UNSPECIFIED Linstaedter, Anja UNSPECIFIED UNSPECIFIED UNSPECIFIED Martens, Carola UNSPECIFIED UNSPECIFIED UNSPECIFIED Gaillard, Camille UNSPECIFIED UNSPECIFIED UNSPECIFIED Ruppert, Jan C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Higgins, Steven I. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mudongo, Edwin I. UNSPECIFIED UNSPECIFIED UNSPECIFIED Scheiter, Simon UNSPECIFIED orcid.org/0000-0002-5449-841X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-155985
DOI:	10.1016/j.ecolmodel.2018.12.013
Journal or Publication Title:	Ecol. Model.
Volume:	395
Page Range:	S. 11 - 23
Date:	2019
Publisher:	ELSEVIER SCIENCE BV
Place of Publication:	AMSTERDAM
ISSN:	1872-7026
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language CLIMATE-CHANGE; ECOSYSTEM STRUCTURE; SOUTH-AFRICA; MANAGEMENT; PRODUCTIVITY; COMMUNITIES; RAINFALL; SAVANNA; QUALITY; FORCES Multiple languages Ecology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15598