Relationship between fire frequency and nitrogen limitation on foliage production in a native grassland community in Victoria, Australia

2007 ◽  
Vol 29 (1) ◽  
pp. 101 ◽  
Author(s):  
J. W. Morgan
Keyword(s):  
Native Species ◽  
Fire History ◽  
Species Coexistence ◽  
Fire Frequency ◽  
N Availability ◽  
N Addition ◽  
Grassland Community ◽  
Native Grasslands ◽  
Native Grassland ◽  
Western Victoria

The relationship between fire frequency (annual v. infrequent) and nitrogen (N) limitation to foliage production in a temperate native grassland community in western Victoria, Australia, was assessed over one growing season using a simple ammonium nitrate addition experiment. Fire history affected the magnitude of the vegetation responses to N addition. At the community level, mean live biomass in infrequently-burned grasslands declined by 20 ± 8% in response to N addition. In contrast, mean biomass increased by 60 ± 15% in annually-burned grasslands in response to N addition. Both grasses and forbs responded positively to N addition in annually-burned grasslands, with forbs responding more substantially than grasses. Foliage production in annually-burned native grasslands therefore appears to be constrained by N availability. The results of this study may have important implications for understanding species coexistence and invasion by non-native species in temperate native grasslands.

Fire regime of a Elionorus muticus Spreng. savanna, western Chaco region, Argentina

2001 ◽  
Vol 10 (1) ◽  
pp. 65 ◽  
Author(s):  
Sandra Bravo ◽  
Carlos Kunst ◽  
Ana Gimenez ◽  
Graciela Moglia
Keyword(s):  
Cross Sections ◽  
Native Species ◽  
Fire History ◽  
Fire Regime ◽  
Woody Species ◽  
Fire Frequency ◽  
Grass Species ◽  
Fire Scars ◽  
Chaco Region ◽  
Native Woody Species

Our objective was to assess the current fire regime of a 600 ha savanna dominated by the grass species Elionorus muticus Spreng., located in Santiago del Estero Province, north-western Chaco region, Argentina. The degree of tolerance of some native woody species to fire, the fire mean fire frequency (FF), and Weibull median probability (WMPI) were evaluated. Sampling sites were located in the ecotone between the savanna and the surrounding forests. A database was developed from fire scars found in cross sections of native tree and shrub species, cut at different heights above ground; that covered the recent 70 years of fire history (1925–1996). Results indicate that the savanna has a mean FF of 0.179 fires year–1 and an FI = 3 years. The mean height of fire scars found in trees and shrubs which indicate medium to high fireline intensities with flame lengths larger than 1 m are frequent in the savanna. Native species have different degrees of tolerance: Aspidosperma quebracho blanco (tree) and Schinopsis quebracho colorado (tree) are more tolerant to fire than Acacia furcatispina (shrub) and A. aroma (shrub). Bark thickness of the tree species (1–1.5 cm in mature individuals) allows them to withstand the frequent, high intensity fires of the savanna.

Interactive effect of climate warming and nitrogen deposition may shift the dynamics of native and invasive species

2020 ◽  
Author(s):  
Guang-Qian Ren ◽  
Chris B Zou ◽  
Ling-Yun Wan ◽  
Jacob H Johnson ◽  
Jian Li ◽  
...  
Keyword(s):  
Invasive Species ◽  
Climate Warming ◽  
Native Species ◽  
Interactive Effect ◽  
N Deposition ◽  
Effect Of Temperature ◽  
N Availability ◽  
N Addition ◽  
Artemisia Argyi ◽  
Species Dynamics

Abstract Aims Projections of invasive species expansion under a warmer world often do not explicitly consider the concurring nitrogen (N) deposition. It remains largely unknown how the convoluted effect of climate warming and N deposition will shift the native and invasive species dynamics. Here, we hypothesize that the concurring increases in N and temperature would promote growth of invasive species greater than that of native species. Methods A controlled greenhouse experiment was conducted to quantify the growth response of an invasive species (Solidago canadensis L.) and a co-existing native species (Artemisia argyi Levl. et Van) under the effects of climate warming, N deposition and their interactions. Important Findings Due to the strong positive effect of N addition, the interactive effect of temperature increase and N addition resulted in an overall significant increase in growth of both invasive and native species, demonstrating that these manipulations may make microhabitats more favorable to plant growth. However, the relative increases in biomass, height and diameter of invasive S. canadensis were significantly lower than those of native A. argyi. This suggests that the vegetative growth superiority of invasive S. canadensis over the native species A. argyi is reduced by the enhanced N availability in the warmer world. Therefore, the inclusion of N deposition may mitigate the projection of invasive species S. canadensis expansion under climate warming.

scholarly journals Susceptibility of a tallgrass prairie to invasion by the herbicidal producing species, Festuca rubra

SURG Journal ◽  
1969 ◽  
Vol 2 (2) ◽  
pp. 11-17
Author(s):  
Jesse Harnden
Keyword(s):  
Tallgrass Prairie ◽  
Mycorrhizal Fungi ◽  
Native Species ◽  
Propagule Pressure ◽  
Arbuscular Mycorrhizal ◽  
Festuca Rubra ◽  
Relative Importance ◽  
Sorghastrum Nutans ◽  
Native Grasslands ◽  
Native Grassland

Disturbance, nutrients, propagule pressure, and the presence of arbuscular mycorrhizal fungi (AMF) have been shown to influence invasion in plant communities, although the relative importance of each remains unclear. A remnant of tallgrass prairie outside Cambridge, ON appears to be resilient to invasion by Festuca rubra, despite its herbicidal properties. A greenhouse experiment was conducted to determine what factors are responsible for the resilience of the native grassland, using synthesized fescue and native sod. The effects of disturbance, nutrient enrichment, propagule pressure, and the presence of AMF and phytotoxin on the establishment ability of F. rubra and the native species Sorghastrum nutans were examined. Propagule pressure was the only factor shown to influence fescue invasion and establishment of S. nutans was unaffected by all factors. These results suggest that the resilience of the native grassland may be due to decreased seed production or viability of F. rubra and not any characteristics of the grassland. Also, the restoration of native grasslands will not be limited by remnants of phytotoxin in the soil, following removal of exotic species.

Elevated nitrogen deposition may advance invasive weed, Solidago canadensis, in calcareous soils

2019 ◽  
Vol 12 (5) ◽  
pp. 846-856 ◽  
Author(s):  
Ling-Yun Wan ◽  
Shan-Shan Qi ◽  
Chris B Zou ◽  
Zhi-Cong Dai ◽  
Guang-Qian Ren ◽  
...  
Keyword(s):  
Native Species ◽  
Environmental Changes ◽  
Calcareous Soils ◽  
N Deposition ◽  
N Availability ◽  
P Availability ◽  
Solidago Canadensis ◽  
N Addition ◽  
Invasive Weed ◽  
P Acquisition

Abstract Aims Change in nitrogen (N) availability regulates phosphorus (P) acquisition and potentially alters the competition among native species and invasive weeds. This study determines how current and projected N deposition affect the growth, the intraspecific and interspecific competitive ability of native and invasive plants in calcareous soils with low P availability. Methods A controlled greenhouse experiment was conducted using sparingly soluble hydroxyapatite (HAP) to simulate the calcareous soils with low P availability. The growth and competitive intensity between an invasive weed (Solidago canadensis) and a native weed (Pterocypsela laciniata) exposed to two levels of N addition representative of current and future N deposition in China were experimentally determined. Important Findings P acquisition and the growth of both S. canadensis and P. laciniata growing alone significantly increased with increasing N level. However, the effect of N addition was reduced when intraspecific or interspecific competition existed. N addition altered the competitive relationship between S. canadensis and P. laciniata allowing S. canadensis to out-compete P. laciniata due to variation in P acquisition from HAP. Elevated N deposition might assist the invasion of S. canadensis in the widely distributed calcareous soils under environmental changes.

Native grassland management: a botanical study of two native grassland management options on a commercial cattle property

2003 ◽  
Vol 25 (1) ◽  
pp. 37 ◽  
Author(s):  
B. McGufficke
Keyword(s):  
Native Species ◽  
Subterranean Clover ◽  
Ground Cover ◽  
Grassland Management ◽  
The Other ◽  
Aerial Application ◽  
Management Options ◽  
Native Grasslands ◽  
Native Grassland ◽  
Bray 1

Variations in the botanical composition of two native grasslands, each managed differently, were investigated on a commercial cattle property in northern NSW. One grassland had not been fertilised, whilst fertiliser and subterranean clover had been applied by aerial application to the other grassland. Soils in both treatments had the same Bray 1 phosphorus level when the study was conducted. The fertilised grassland was stocked at triple the rate of the other grassland. Although more native species were recorded in the fertilised grassland many species had a lower frequency than in the unfertilised grassland; and introduced species tended to have a higher frequency in the fertilised grassland. ground cover was significantly higher in the fertilised grassland in spite of the greatly increased stocking rate.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

scholarly journals RIQUEZA ESPECÍFICA EM ÁREAS DE CAMPO NATIVO IMPACTADAS POR VISITAÇÃO TURÍSTICA E PASTEJO NO PARQUE NACIONAL DOS CAMPOS GERAIS, PR

FLORESTA ◽  
2011 ◽  
Vol 41 (2) ◽  
Author(s):  
Karine Dalazoana ◽  
Rosemeri Segecin Moro
Keyword(s):  
Species Diversity ◽  
National Park ◽  
Anthropogenic Factors ◽  
Species Number ◽  
Anthropogenic Pressure ◽  
Grassland Community ◽  
Campos De Altitude ◽  
Resistant Species ◽  
Native Grassland ◽  
Selection Of

O Parque Nacional dos Campos Gerais (PNCG) detém áreas de campos de altitude sob forte pressão antrópica, com a expansão das atividades agrícolas, pecuária, silvicultura e visitação turística desordenada. Devido ao impacto gerado, existe uma tendência à diminuição da riqueza específica, através da seletividade de espécies. Este trabalho analisa a resposta das comunidades campestres em termos de composição de espécies aos impactos de pastejo, roçada e pisoteio humano. Em quatro estações de coleta, foram determinados 107 táxons distribuídos em 23 famílias botânicas. As famílias com maior riqueza específica foram Asteraceae e Poaceae, ambas com 24 táxons, e Fabaceae, com 14 táxons. A riqueza específica variou de 27 a 75 espécies, com maior riqueza na estação não pastejada nem roçada, apenas visitada por turistas. O levantamento mostrou que, apesar da pressão antrópica, as áreas estudadas exibem considerável riqueza específica quando comparadas a outros trabalhos na região, mantendo ainda seu potencial biótico dinâmico. Floristicamente, os impactos gerados por gado ou por manejo com roçadeira se equivalem. Seis gêneros têm potencial para serem utilizados como bioindicadores de áreas conservadas: Croton, Galactia, Periandra, Cuphea, Pavonia e Commelina, mas há necessidade de ampliação das áreas estudadas para estabelecer mais claramente seu valor de bioindicação.Palavras-chave: Campo nativo; Campos Gerais; área impactada; pastejo; visitação turística. AbstractThe species diversity in native grassland areas that are under impact of tourism and grazing at Campos Gerais National Park, Parana, Brazil. Campos Gerais National Park (PNCG) has areas of grassland under high anthropogenic pressure, as expansion of agricultural activities, livestock, forestry and disorderly tourism. Due to these impacts, there is a tendency to decrease local biodiversity by selection of more resistant species. This paper focuses the grassland community answers to mowing, grazing and tourism. In four sampling sites it was determined 107 taxa belonging to 23 botanic families. The main families are Asteraceae (24 taxa), Poaceae (24 taxa) and Fabaceae (14 taxa). Species diversity varied from 27 to 75 species. In relation to species number, non-grazed areas presented greater diversity than other ones; it points to that touristic visitation may cause lower impact than grazing or mowing. In spite of the anthropogenic factors, the focused sites presented high specific diversity in relation to related areas. In relation to species diversity, grazing or mowing are equal. Six genera presented potentiality as bioindicators of preserved environments: Croton, Galactia, Periandra, Cuphea, Pavonia, and Commelina, although more sample areas are necessary to reliable results.Keywords: Grasslands; Campos Gerais; impacted area; grazing; touristic activities.

Using simulation to map fire regimes: an evaluation of approaches, strategies, and limitations

2003 ◽  
Vol 12 (4) ◽  
pp. 309 ◽  
Author(s):  
Robert E. Keane ◽  
Geoffrey J. Cary ◽  
Russell Parsons
Keyword(s):  
Geographical Information Systems ◽  
Fire History ◽  
Fire Regime ◽  
Wildland Fire ◽  
Fire Regimes ◽  
Simulation Modelling ◽  
Fire Frequency ◽  
Geographical Information ◽  
Spatially Explicit ◽  
Eastern Australia

Spatial depictions of fire regimes are indispensable to fire management because they portray important characteristics of wildland fire, such as severity, intensity, and pattern, across a landscape that serves as important reference for future treatment activities. However, spatially explicit fire regime maps are difficult and costly to create requiring extensive expertise in fire history sampling, multivariate statistics, remotely sensed image classification, fire behaviour and effects, fuel dynamics, landscape ecology, simulation modelling, and geographical information systems (GIS). This paper first compares three common strategies for predicting fire regimes (classification, empirical, and simulation) using a 51�000�ha landscape in the Selway-Bitterroot Wilderness Area of Montana, USA. Simulation modelling is identified as the best overall strategy with respect to developing temporally deep spatial fire patterns, but it has limitations. To illustrate these problems, we performed three simulation experiments using the LANDSUM spatial model to determine the relative importance of (1) simulation time span; (2) fire frequency parameters; and (3) fire size parameters on the simulation of landscape fire return interval. The model used to simulate fire regimes is also very important, so we compared two spatially explicit landscape fire succession models (LANDSUM and FIRESCAPE) to demonstrate differences between model predictions and limitations of each on a neutral landscape. FIRESCAPE was developed for simulating fire regimes in eucalypt forests of south-eastern Australia. Finally, challenges for future simulation and fire regime research are presented including field data, scale, fire regime variability, map obsolescence, and classification resolution.

Fire regimes and their correlates in the Darwin region of northern Australia

2007 ◽  
Vol 13 (3) ◽  
pp. 177 ◽  
Author(s):  
Owen Price ◽  
Bryan Baker
Keyword(s):  
Fire History ◽  
Ad Hoc ◽  
Fire Regime ◽  
Negative Impact ◽  
Fire Suppression ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Dry Season ◽  
Generalized Linear Modelling

A nine year fire history for the Darwin region was created from Landsat imagery, and examined to describe the fire regime across the region. 43% of the region burned each year, and approximately one quarter of the fires occur in the late dry season, which is lower than most other studied areas. Freehold land, which covers 35% of the greater Darwin region, has 20% long-unburnt land. In contrast, most publicly owned and Aboriginal owned land has very high fire frequency (60-70% per year), and only 5% long unburnt. It seems that much of the Freehold land is managed for fire suppression, while the common land is burnt either to protect the Freehold or by pyromaniacs. Generalized Linear Modelling among a random sample of points revealed that fire frequency is higher among large blocks of savannah vegetation, and at greater distances from mangrove vegetation and roads. This suggests that various kinds of fire break can be used to manage fire in the region. The overall fire frequency in the Darwin region is probably too high and is having a negative impact on wildlife. However, the relatively low proportion of late dry season fires means the regime is probably not as bad as in some other regions. The management of fire is ad-hoc and strongly influenced by tenure. There needs to be a clear statement of regional fire targets and a strategy to achieve these. Continuation of the fire mapping is an essential component of achieving the targets.

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