Mineral nutrition and specific leaf area of plants under contrasting long-term fire frequencies: a case study in a mesic savanna in Australia
Marcelo Claro de Souza1,2 • Davi Rodrigo Rossatto3 • Garry David Cook4 •
Ryosuke Fujinuma5 • Neal William Menzies5 • Leonor Patricia Cerdeira Morellato6 •
Received: 24 January 2015 / Revised: 26 August 2015 / Accepted: 28 August 2015 Springer-Verlag Berlin Heidelberg 2015
Key message The association between frequent longterm fires and soil fertility may control the nutritional status and leaf scleromorphism of Australian savanna species.
Abstract Fire frequency is considered to be a controlling factor for the structure of savanna vegetation, also affecting functional aspects of plants, yet studies contrasting longterm burnt and unburnt sites within the same area are rare.
At fire-protected sites, one may expect to find woody vegetation with non-sclerophyllous leaves exhibiting a high nutrient concentration and growing on soils of high fertility. Using a burnt (14 times within the last 20 years) and an unburnt site (over the same period) within the same area of a mesic Australian savanna, we compared the soil fertility, specific leaf area (SLA) and leaf macronutrient concentration of the exclusive (species that occur at a single site), common (species that occur at both sites) and total (exclusive and common species combined) sampled tree species from the two sites. The exclusive, common and total sampled tree species had a lower SLA when growing at the burnt site than at the unburnt site. Soil from the burnt site was less fertile than the soil from the unburnt site, and the plants from the burnt site exhibited lower leaf nutrient concentrations when compared with those from the unburnt site. The association between fire and soil fertility was consistent with the differences in leaf scleromorphism between the sites under contrasting fire frequencies.
Keywords Fire management Leaf scleromorphism
Native plant nutrition Soil fertility
The species composition and individual species characteristics of savanna vegetation are shaped by fire (Williams and Cook 2001; Bond et al. 2005; Hoffmann et al. 2012), soil water availability (Cook et al. 2002; Scholes et al. 2004; Scott et al. 2009; Rossatto et al. 2012; Murphy et al. 2015), soil nutrient stocks and climate (Pinheiro and
Monteiro 2010; Lehmann et al. 2011, 2014). Savannas around the world are frequently burnt by natural or anthropogenic means, and up to 75 % of some savanna areas burn annually (Hao et al. 1990), which affects plant recruitment (Rossiter-Rachor et al. 2008) and development (Beringer et al. 2015) and their phenological and functional events (Hoffmann 1998; Pausas et al. 2004; Alvarado et al.
Communicated by A. Franco. & Marcelo Claro de Souza email@example.com 1 Departamento de Botaˆnica, Instituto de Biocieˆncias,
Programa de Po´s Graduac¸a˜o em Biologia Vegetal, Univ
Estadual Paulista, Unesp, Av. 24-A, 1515, Rio Claro,
SP 13506-900, Brazil 2 Present Address: Departamento de Cieˆncias Farmaceˆuticas,
Faculdade de Cieˆncias Farmaceˆuticas de Ribeira˜o Preto,
Universidade de Sa˜o Paulo, USP, Av. do Cafe´ s/n,
Ribeira˜o Preto, SP 14040-903, Brazil 3 Departamento de Biologia, Faculdade de Cieˆncias Agra´rias e
Veterina´rias, Univ Estadual Paulista, Unesp, Via de Acesso
Paulo Donato Castellani s/n, Jaboticabal, SP 14884-900,
Brazil 4 CSIRO Land and Water Flagship, Darwin, NT, Australia 5 School of Agriculture and Food Sciences, University of
Queensland, Brisbane, Australia 6 Departamento de Botaˆnica, Instituto de Biocieˆncias, Univ
Estadual Paulista, Unesp, Av. 24-A, 1515, Rio Claro,
SP 13506-900, Brazil 123
DOI 10.1007/s00468-015-1285-1 2014). Despite the intense wet season from December to
May, Australian savannas are the most frequently burnt vegetation in the world (Andersen et al. 2005; Chuvieco et al. 2008; Beringer et al. 2015). Across Australian savannas, half of the vegetation burns annually (Edwards et al. 2001; Andersen et al. 2005; Beringer et al. 2015) and in the Kakadu National Park (Northern Territory, Australia) few areas remain unburnt for more than 2–3 years (KBMPA 1999; Cook 2001).
Soils from savannas often have limited nutrient availability, affecting the leaf nutrient concentrations (mainly N and P) and leading to changes in the specific leaf area (SLA, ratio of leaf area per unit leaf dry mass) of some
Australian species (Wright et al. 2001; Prior et al. 2003, 2005). Frequent incidence of fire over a long time frame may limit the available pool of soil nutrients, and fire may also diminish the soil organic matter concentration and accumulation (Andersson et al. 2004; Silva and Batalha 2008) when litter is incinerated (Oesterheld et al. 1999). In addition, frequent fires can result in savanna physiognomies with a conspicuous dominance of grasses, whereas trees and shrubs are more evident in savannas with lower fire incidence (Sankaran et al. 2005). Conversely, savanna vegetation protected from fire for long periods ([10 years) becomes less flammable as the density of trees increases over time, resulting in low sunlight interception and less vegetative biomass at the ground level, due to denser tree crowns, when compared to frequently burnt areas (Andersen et al. 2005; Beringer et al. 2015). Therefore, sunlight availability may also influence SLA in such a manner that
Table 1 List of plant species from the burnt and unburnt
Australian savanna sites,
Northern Territory, 2013
Family Species Burnt Unburnt
Anacardinaceae Buchanania obovata Engl. 9 9
Combretaceae Terminalia ferdinandiana Exell 9 9
Lecythidaceae Planchonia careya (F.Muell) R.Knuth 9 9
Leguminosae Acacia dimidiata Benth. 9
Leguminosae Acacia lamprocarpa O.Schwarz 9
Leguminosae Erythrophleum chlorostachys (F.Muell.) Baillon 9
Leguminosae Acacia auriculiformis Benth. 9
Leguminosae Exocarpus latifolius Baker 9