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Health of remnant woodlands in fragments under distinct grazing regimes

Citation

Close, DC and Davidson, NJ and Watson, T, Health of remnant woodlands in fragments under distinct grazing regimes, Biological Conservation, 141, (9) pp. 2395-2402. ISSN 0006-3207 (2008) [Refereed Article]

DOI: doi:10.1016/j.biocon.2008.07.006

Abstract

Fragmented remnant woodlands in agricultural landscapes are of high conservation value world-wide. Many eucalypts in agricultural landscapes of Australia are in decline. We aimed to investigate nutrient enrichment as a process that may contribute to eucalypt decline. We studied remnant woodlands that had been exposed to distinct recent and current livestock grazing treatments: Currently Intense Grazed; Recently Intense Grazed (until 3 years ago); Recent Intermediate Grazed; and Recent Lightly Grazed by livestock. We assessed soil nutrient status and penetrability, eucalypt foliar nutrition and stable isotope ratios for N and C, attributes of understorey vegetation, and tree health. Soils of the Currently Intense Grazed treatment had high levels of ammonium and Colwell-P. Total N, P, C:N ratio and soil penetrability were generally high in Currently intense Grazed and Recently Intense Grazed treatments relative to Recent Intermediate Grazed and Recent Lightly Grazed treatments. Foliar N, N stable isotope ratios, P and carbon stable isotope ratios (delta C-13 ) were generally higher (less negative delta C-13) in trees on Currently Intense Grazed and Recently Intense Grazed treatments than in trees on Recent Intermediate Grazed and Recent Lightly Grazed treatments. Soil surface litter, tall and low shrubs and rock were positively correlated with tree health. Grasses and eucalypt foliar N, P and delta C-13 were negatively correlated with tree health. Soil nutrient enrichment increased with increasing grazing intensity and was associated with increased weed invasion and with poor tree health that was in turn correlated to increased foliar N and P and less negative delta C-13 in woodland trees in this study. We argue that minimising soil nutrient enrichment of fragmented remnant woodlands is important, given the association of elevated soil nutrition with poor tree health, to ensure the persistence of eucalypts in agricultural landscapes. (C) 2008 Elsevier Ltd. All rights reserved.

Item Details

Item Type:Refereed Article
Keywords:EUCALYPTUS-SALMONOPHLOIA; SOUTHEASTERN AUSTRALIA; HABITAT FRAGMENTATION; SCATTERED TREES; LANDSCAPES; SOIL; RESTORATION; NITROGEN; CONSERVATION; MANAGEMENT
Research Division:Agricultural and Veterinary Sciences
Research Group:Forestry Sciences
Research Field:Forestry Management and Environment
Objective Division:Environment
Objective Group:Remnant Vegetation and Protected Conservation Areas
Objective Field:Remnant Vegetation and Protected Conservation Areas in Forest and Woodlands Environments
Author:Close, DC (Associate Professor Dugald Close)
Author:Davidson, NJ (Dr Neil Davidson)
Author:Watson, T (Mr Tom Watson)
ID Code:55219
Year Published:2008
Web of Science® Times Cited:22
Deposited By:Plant Science
Deposited On:2009-03-06
Last Modified:2015-02-04
Downloads:0

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