Vegetation responses to fire history and soil properties in grazed semi-arid tropical savanna

Lebbink, Gabrielle; Fensham, R. J.; Cowley, Robyn

doi:10.1071/rj17075

Cited by 6 publications

(8 citation statements)

References 55 publications

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“…Although changes in vegetation structure represent modifications in habitat for plants and animals, fire-driven changes in plant communities of tropical savannas due to fire are much more about structure than species composition or biodiversity (Higgins et al, 2007;van Wilgen et al, 2007;Lebbink et al, 2018), since fire does not eliminate typical savanna species. No biodiversity losses due to fire have been consistently observed in savannas for most animal groups, such as arthropods (but see Morais and Benson, 1988;Andersen and Müller, 2000;Maravalhas and Vasconcelos, 2014;Vasconcelos et al, 2017), birds (Cavalcanti and Alves, 1997;Corbett et al, 2003;Mills, 2004;Reis et al, 2016), mammals (Vieira, 1999;Prada and Marinho-Filho, 2004;Beale et al, 2018), reptiles (Griffiths and Christian, 1996;Corbett et al, 2003;Langford et al, 2007;Morais et al, 2011;Costa et al, 2013), and amphibians (Corbett et al, 2003;Langford et al, 2007;Morais et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

No Net Loss of Species Diversity After Prescribed Fires in the Brazilian Savanna

Durigan

Pilon

Abreu

et al. 2020

Front. For. Glob. Change

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Although savannas are fire-adapted ecosystems, prescribing fire for biodiversity conservation remains controversial at least in some regions where savannas occur. Faced with uncertainty, many decision makers and even scientists are still reluctant to prescribe fire for conservation purposes in fire-prone ecosystems, invoking the precautionary principle. Knowledge gaps on the ideal fire regime, such as how and when to burn, and especially the fear of biodiversity losses, are among the main arguments against fire management applied to remnants of native savanna vegetation. To inform this debate, we assessed the impact of prescribed fires on diversity of plants (different growth forms), ants, frogs, lizards, birds, and small mammals, in savannas and grasslands of the Brazilian Cerrado. We assessed the existing species richness, composition, and abundance in areas subjected to long periods of fire suppression and compared to that observed over a short period after prescribed dry-season fires, within each group of plants and animals. Whenever possible, we carried out separate analyses for grassland and savanna. Burning did not significantly reduce species richness of any of the groups analyzed, but had a positive effect on richness of graminoids in grassland. When analyzed at the species level, abundance of most animal groups did not show consistent responses to fire, except for a decrease in some frog populations in grasslands. Forbs, graminoids, and subshrubs increased in abundance after fire in grassland areas, though in savanna areas, abundance of forbs, and subshrubs tended to decline after fire. Species composition changed little in response to fire as indicated by low levels of dissimilarity between burned and unburned areas. These results confirm the high resilience of Cerrado biota to fire, as expected for savanna ecosystems in general. Besides, we demonstrate here that the risk of biodiversity losses cannot justify the objections to the use of prescribed fire for conservation purposes in the Cerrado.

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Section: Discussionmentioning

confidence: 99%

No Net Loss of Species Diversity After Prescribed Fires in the Brazilian Savanna

Durigan

Pilon

Abreu

et al. 2020

Front. For. Glob. Change

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“…Species present in the first 2 m × 0.33 m subplot were assigned an abundance score of 4, those in the 2 m × 0.67 m subplot were assigned an abundance score of 3, species present in the next 2 m × 2 m section were assigned an abundance score of 2 and those in the final subplot were assigned an abundance score of 1 (Fensham et al, 2017). The sampling technique was chosen because within a few square metres in a grassland community there exist a large and diverse assemblage of life forms (Gibson‐Roy & Delpratt, 2015) and previous studies conducted validates that the quadrat sizes and values are appropriate for the grassland environment (Fensham et al, 2017; Lebbink et al, 2018). Nomenclature of plant species follows Bostock and Holland (2013).…”

Section: Methodsmentioning

confidence: 99%

Passive regeneration of subtropical grassland vegetation in a chronosequence of ex‐cultivated fields in Australia

Osazuwa

Dwyer

John

2021

Applied Vegetation Science

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Aim In Australia, natural grasslands largely occur on fertile clay soils and have consequently been extensively cultivated since European settlement. Other studies have demonstrated that passive restoration of subtropical grassland is possible in environments where there is substantial native remnant vegetation in the surrounding landscape. This study examined a chronosequence of abandoned fields to investigate the recovery of fragmented grassland in a matrix of cultivated land with significant exotic species that may impede succession. Location Darling Downs, Queensland, Australia. Methods In this study we surveyed a chronosequence of ex‐cultivated subtropical grasslands in Queensland's Darling Downs, where only 1% of the original grasslands remain. Floristic surveys were carried out in 80 fallow sites up to 51 years old, and data were compared with 16 previously surveyed remnant grasslands on the same land type. Results Richness of native species increased with time since cultivation and approached, but did not reach, that of remnant grasslands after 51 years, whereas the richness of exotics declined with time since cultivation. Rainfall and grazing positively and negatively affected exotic plant abundance respectively and these factors had no significant direct or indirect effect on the native species richness. In terms of composition, fallow grasslands supported 54% of the native plant species from remnant grasslands after 51 years. The native perennial grasses Dichanthium sericeum and Aristida leptopoda were the only dominant species in the remnants that were present in more than 60% of the fallow grasslands. Of the species from remnants that were “missing” from fallow sites, most were native perennial forbs and grasses. Compositional dissimilarity of fallow grassland to remnant grasslands remained high after 51 years (78%). Grassland species that are uncommon in nearby hill woodlands were preferentially absent in fallow grassland and this partly explains the slow compositional recovery. Conclusion In a highly fragmented landscape, passive restoration is only partially effective. The restoration of grassland is probably enhanced by repositories of native seeds from hill woodlands that are too rocky to cultivate. However, some species may have to be actively reintroduced to achieve complete recovery. In this landscape, where grazing is a dominant land use, exotic species do not seem to impede succession.

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“…This stability is based around a set of 'core species', especially perennial grasses, in regularly burnt sites. Savanna ground layers generally have a consistent post-fire flush of ephemeral species, with changes following longer intervals between fire (Williams et al 2003;Scott et al 2012;Lebbink et al 2018).…”

Section: Fire Effects On the Ground Layermentioning

confidence: 99%

“…Site 4 which also experienced five fires had lower species richness, as did the very infrequently burnt Site 1. The influence of site substrate is also a fundamental attribute in determining species richness (Scott et al 2012;Lebbink et al 2018). Site 1A, which experienced the highest level of disturbance mainly as grazing, had the lowest species richness and the highest non-native species contribution.…”

Section: Fire Effects On the Ground Layermentioning

confidence: 99%

“…Similarly, over a 5-year period in open savanna forest in Kaplaga in the Northern Territory (Andersen et al 2005), there were no detectable effect of fire on floristic composition of the grass layer. The short-term increase in ephemeral species and perennial forbs after fire is usually attributed to the reduction in perennial grasses in semiarid (Kutt and Woinarski 2007;Cowley et al 2014;Fensham et al 2015;Lebbink et al 2018) and tropical vegetation (Williams et al 2003;Andersen et al 2005) in Queensland and the Northern Territory. The contribution of annual and ephemeral species in this study was low for all sites both in terms of cover and species richness.…”

Section: Fire Effects On the Ground Layermentioning

confidence: 99%

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Dynamics of the ground layer communities of tropical eucalypt woodlands of northern Queensland

Neldner

Butler

2021

Aust. J. Bot.

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This paper presents insights from long-term monitoring into the dynamics of savanna plant species composition, specifically on the ground layer. Key questions are (1) how much variation is there from year to year in plant species abundance and composition? And (2) is there evidence of directional change in community composition? Five sites were located near Mareeba, north-eastern Australia, and sampled 18 times with fixed 500-m2 plots at the annual peak of plant species richness over 23 years. The sites were located in eucalypt communities across an altitudinal range of 460 m. Sampling involved systematic searching of all plant species visible above ground. The results show variation from year to year among satellite herbaceous species, with more than 50% of grasses and forbs observed at a given site only being detected at half or fewer of the 18 samplings. Herbaceous composition did not show clear signs of directional change relative to inter-annual variability. Over the 23 years, there were three very dry periods and 4 very wet years. Rainfall variation affected total cover more than plant species composition or richness. Several fires and episodes of grazing affected ground cover but did not have a lasting impact on cover or diversity. The cover and composition of the ground layer is consistently dominated by the core perennial grasses Themeda triandra Forssk. and Heteropogon triticeus (R.Br.) Stapf, with many species collectively contributing minimally to the overall cover but significantly to richness. Many herb species are persistent long-lived perennials which do not appear above ground every year. The number of naturalised plants in the ground layer was consistently low. Overall, the ground layer communities appear to be very stable in these woodlands that have been burnt 3–5 times in 23 years. High inter-annual variability of subdominant species is consistent with other studies, and emphasises the need for replication in time in ecological sampling.

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Vegetation responses to fire history and soil properties in grazed semi-arid tropical savanna

Cited by 6 publications

References 55 publications

No Net Loss of Species Diversity After Prescribed Fires in the Brazilian Savanna

No Net Loss of Species Diversity After Prescribed Fires in the Brazilian Savanna

Passive regeneration of subtropical grassland vegetation in a chronosequence of ex‐cultivated fields in Australia

Dynamics of the ground layer communities of tropical eucalypt woodlands of northern Queensland

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