scholarly journals Grass Canopy Architecture Influences Temperature Exposure at Soil Surface

Fire ◽  
2018 ◽  
Vol 1 (3) ◽  
pp. 35 ◽  
Author(s):  
Xiulin Gao ◽  
Dylan Schwilk
Keyword(s):  
Fire Regime ◽  
Fire Behavior ◽  
Soil Surface ◽  
Grass Species ◽  
Canopy Architecture ◽  
Height Ratio ◽  
Biomass Density ◽  
Litter Flammability ◽  
Temperature Exposure ◽  
Density And Biomass

There is increasing recognition that plant traits contribute to variations in fire behavior and fire regime. Diversity across species in litter flammability and canopy flammability has been documented in many woody plants. Grasses, however, are often considered homogeneous fuels in which any flammability differences across species are attributable to biomass differences alone and therefore are of less ecological interest, because biomass is hugely plastic. We examined the effect of grass canopy architecture on flammability across eight grass species in short grass steppe of New Mexico and Texas. To characterize grass canopy architecture, we measured biomass density and “biomass-height ratio” (the ratio of canopy biomass above 10 cm to that of biomass below 10 cm). Indoor flammability experiments were performed on air-dried individual plants. As expected, plant biomass influenced all flammability measures. However, biomass-height ratio had additional negative effect on temperature exposure at soil surface (accumulation of mean temperature >100 °C) in well-cured grasses, which is an important fire behavior metric predicting soil heating and meristem survival. This canopy architecture effect, however, needs further investigation to be isolated from biomass density due to correlation of these two traits. This result demonstrates the potential for species-specific variation in architecture to influence local fire effects in grasses.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

Urochloa platyphylla (broadleaf signalgrass).

2021 ◽  
Author(s):  
Julissa Rojas-Sandoval ◽  
Pedro Acevedo-Rodríguez
Keyword(s):  
Environmental Conditions ◽  
Crop Residue ◽  
Soil Surface ◽  
Grass Species ◽  
Crop Fields ◽  
Wide Range ◽  
Germinating Seeds

Abstract U. platyphylla is a weedy grass species commonly found in disturbed, open and sandy sites such as crop fields, ditches and roadsides. It is considered a troublesome weed because of its tolerance to some herbicides principally in maize plantations (Chamblee et al., 1982; Gallaher et al.,1999). U. platyphylla is highly adaptable and it is able to germinate and grow throughout a wide range of soil and environmental conditions (Burke et al., 2003). Additionally, its seeds may remain on the crop residue until pre-emergence herbicides are no longer effective in controlling the germinating seeds, at which time the seeds fall to the soil surface and germinate (Alford et al., 2005).

Effect of fire regime on the grass community of the humid savanna of Lamto, Ivory Coast

2018 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kouamé Fulgence Koffi ◽  
Aya Brigitte N’Dri ◽  
Jean-Christophe Lata ◽  
Souleymane Konaté ◽  
Tharaniya Srikanthasamy ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Ivory Coast ◽  
Fire Regime ◽  
Fire Regimes ◽  
Abundant Species ◽  
Grass Species ◽  
The Third ◽  
Humid Savanna ◽  
The Impact ◽  
Tussock Grasses

AbstractThis study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.

Spatial fuel data products of the LANDFIRE Project

2009 ◽  
Vol 18 (3) ◽  
pp. 250 ◽  
Author(s):  
Matthew C. Reeves ◽  
Kevin C. Ryan ◽  
Matthew G. Rollins ◽  
Thomas G. Thompson
Keyword(s):  
Bulk Density ◽  
Vegetation Structure ◽  
Fire Regime ◽  
Fire Behavior ◽  
The United States ◽  
Surface Fire ◽  
Spatial Coverage ◽  
Data Products ◽  
Fuel Models ◽  
Canopy Bulk Density

The Landscape Fire and Resource Management Planning Tools (LANDFIRE) Project is mapping wildland fuels, vegetation, and fire regime characteristics across the United States. The LANDFIRE project is unique because of its national scope, creating an integrated product suite at 30-m spatial resolution and complete spatial coverage of all lands within the 50 states. Here we describe development of the LANDFIRE wildland fuels data layers for the conterminous 48 states: surface fire behavior fuel models, canopy bulk density, canopy base height, canopy cover, and canopy height. Surface fire behavior fuel models are mapped by developing crosswalks to vegetation structure and composition created by LANDFIRE. Canopy fuels are mapped using regression trees relating field-referenced estimates of canopy base height and canopy bulk density to satellite imagery, biophysical gradients and vegetation structure and composition data. Here we focus on the methods and data used to create the fuel data products, discuss problems encountered with the data, provide an accuracy assessment, demonstrate recent use of the data during the 2007 fire season, and discuss ideas for updating, maintaining and improving LANDFIRE fuel data products.

Germination response to heat and smoke of 22 Poaceae species from grassy woodlands

2005 ◽  
Vol 53 (5) ◽  
pp. 445 ◽  
Author(s):  
S. Clarke ◽  
K. French
Keyword(s):  
Heat Treatment ◽  
Species Richness ◽  
Exotic Species ◽  
Fire Regime ◽  
Fire Regimes ◽  
Grass Species ◽  
Percentage Germination ◽  
Germination Response ◽  
Eastern Australia ◽  
Smoke Water

Grasses form an important component of grassy woodlands, although their response to fire has been understudied. In this study, fire germination responses of 22 Poaceae species from an endangered grassy-woodland community in eastern Australia were investigated. Seeds of 20 native and two exotic species were subjected to heat (no heat, 40, 80 and 120°C) and smoke treatment (10% dilution smoke water) and the percentage germination was compared. Germination response of species showed no consistent pattern to phylogeny and was highly variable. Germination in six species was unaffected by the application of heat or smoke. In five species, heat, irrespective of smoke application, influenced germination. Smoke, irrespective of heat treatment, influenced six species. For a further six species, the effect of smoke varied with temperature. These results suggest that fire regimes will influence the recruitment of grass species differentially and maintaining regional species richness is likely to require the maintenance of a heterogeneous fire regime across the landscape.

scholarly journals Grass Species Flammability, Not Biomass, Drives Changes in Fire Behavior at Tropical Forest-Savanna Transitions

2018 ◽  
Vol 1 ◽  
Author(s):  
Anabelle W. Cardoso ◽  
Imma Oliveras ◽  
Katharine A. Abernethy ◽  
Kathryn J. Jeffery ◽  
David Lehmann ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Fire Behavior ◽  
Grass Species ◽  
In Fire

scholarly journals Have Historical Land Use/Land Cover Changes Triggered a Fire Regime Shift in Central Spain?

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 44 ◽  
Author(s):  
Cristina Montiel-Molina ◽  
Lara Vilar ◽  
Catarina Romão Sequeira ◽  
Oskar Karlsson ◽  
Luis Galiana-Martín ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Fire History ◽  
Fire Regime ◽  
Influencing Factor ◽  
Fire Behavior ◽  
Landscape Dynamics ◽  
Central Spain ◽  
Lulc Changes ◽  
Systemic Analysis

Fire is one of the main disturbance factors shaping the landscape, and landscape is a key driver of fire behavior. Considering the role played by land use and land cover (LULC) changes as the main driver of landscape dynamics, the aim of this study was to calculate and analyze (i) the real impact of fire on LULC changes and (ii) how these LULC changes were influencing the fire regime. We used methods of historical geography and socio-spatial systemic analysis for reconstructing and assessing the LULC change and fire history in six case studies in the Central Mountain System (Spain) from archival documentary sources and historical cartography. The main result is an accurate dataset of fire records from 1497 to 2013 and a set of LULC maps for three time points (1890s–1930s, 1956–1957, and the 2000s). We have shown the nonlinear evolution of the fire regime and the importance of the local scale when assessing the interaction of landscape dynamics and fire regime variation. Our findings suggest that LULC trends have been the main influencing factor of fire regime variation in Central Spain since the mid-19th century.

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.

Factors affecting the density of populations of common snapping turtles (Chelydra serpentina serpentina)

1988 ◽  
Vol 66 (5) ◽  
pp. 1233-1240 ◽  
Author(s):  
David A. Galbraith ◽  
Christine A. Bishop ◽  
Ronald J. Brooks ◽  
W. Len Simser ◽  
Karen P. Lampman
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Primary Productivity ◽  
Suitable Habitat ◽  
Adult Size ◽  
Chelydra Serpentina ◽  
Biomass Density ◽  
Factors Affecting ◽  
Snapping Turtles ◽  
Density And Biomass

Density, biomass, and sex ratio were measured in two populations of snapping turtles (Chelydra serpentina) in Ontario in 1984 and 1985. The more southern population inhabited a nutrient-enriched pond at an unusually high density and biomass density (66/ha, 340 kg/ha), and exhibited a significantly male-biased sex ratio (1.96:1) but no significant sexual dimorphism in adult size. The northern population inhabited dystrophic or oligotrophic ponds at a low density (2.4/ha, 16 kg/ha), did not show a significant bias in adult sex ratio, but did have a strong sexual dimorphism in adult size, males having approximately twice the mass of females. A comparison among several populations indicated that density was negatively correlated with latitude and with surface area of suitable habitat. Density and biomass density were significantly higher in habitats of relatively high primary productivity, which tended to be at relatively low latitudes. Therefore, important proximal factors affecting density of these turtles are likely to be primary productivity and recruitment history. Differences in sex ratio and sexual dimorphism in size between the two Ontario populations did not support the hypothesis that the latter is due to sexual selection.

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