Document


Title

African grazing lawns - how fire, rainfall, and grazer numbers interact to affect grass community states
Document Type: Journal Article
Author(s): Sally Archibald
Publication Year: 2008

Cataloging Information

Keyword(s):
  • abiotic regulation
  • Africa
  • Bison bison
  • distribution
  • ecosystem dynamics
  • fire frequency
  • fire management
  • grass community
  • grasses
  • grassland
  • grazing
  • grazing lawns
  • heterogeneity
  • internal feedbacks
  • mammals
  • nutrients
  • plant communities
  • plant growth
  • precipitation
  • pyric herbivory
  • range management
  • savannas
  • season of fire
  • simulation model
  • size classes
  • soil nutrients
  • soils
  • South Africa
  • statistical analysis
  • wildfires
  • wildlife
Region(s):
  • International
Record Maintained By:
Record Last Modified: June 1, 2018
FRAMES Record Number: 18108
Tall Timbers Record Number: 21904
TTRS Location Status: In-file
TTRS Call Number: Journals-J
TTRS Abstract Status: Okay, Fair use, Reproduced by permission

This bibliographic record was either created or modified by the Tall Timbers Research Station and Land Conservancy and is provided without charge to promote research and education in Fire Ecology. The E.V. Komarek Fire Ecology Database is the intellectual property of the Tall Timbers Research Station and Land Conservancy.

Description

Grazing lawns are recognized as important components of many savanna ecosystems, but there is no clarity on their origin or their stability in space and time. Some researchers believe soil nutrients control grazing lawn distributions. Others believe feedbacks created by herding mammals grazing in patches can promote the spread of grazing lawns without soil nutrient differences. This in turn is affected by rainfall and fire. We presented a simulation model that tests the conditions required for the initiation and spread of grazing lawns. Lawns were shown to develop in a homogeneous soil substrate, but only during periods of low rainfall, high grazer densities, and infrequent fires. Including heterogeneity in the model did not increase grazing lawn area but did reduce the effectiveness of frequent fires in preventing their establishment. We compared these results with conditions in a typical savanna park in Southern Africa. Running the model under current fire, grazing, and rainfall conditions reproduced the current grazing lawn proportions in the park. Using lower fire frequencies and higher grazer densitiessuch as were experienced in the park in the last 100 years-could more than double the proportion of grazing lawns in the park.

Online Link(s):
Citation:
Archibald, Sally. 2008. African grazing lawns - how fire, rainfall, and grazer numbers interact to affect grass community states. Journal of Wildlife Management 72(2):492-501.