scholarly journals Effect of fire regimes on the demographic parameters of the perennial tussock grasses of a humid savanna

2019 ◽  
Vol 30 (5) ◽  
pp. 950-962
Author(s):  
Kouamé Fulgence Koffi ◽  
Aya Brigitte N'Dri ◽  
Jean‐Christophe Lata ◽  
Souleymane Konaté ◽  
Tharaniya Srikanthasamy ◽  
...  
Keyword(s):  
Fire Regimes ◽  
Demographic Parameters ◽  
Humid Savanna ◽  
Tussock Grasses

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.

scholarly journals Does the Date of Burning Affect Carbon and Nutrient Losses in a Humid Savanna of West Africa?

2018 ◽  
Vol 8 (3) ◽  
pp. 102
Author(s):  
Aya B. N Dri ◽  
Louis N. Konan
Keyword(s):  
West Africa ◽  
Soil Nutrients ◽  
Aboveground Biomass ◽  
Fire Regimes ◽  
Flame Height ◽  
Nutrient Losses ◽  
Humid Savanna

A significant impact of fires is the transfer to the atmosphere of the elements contained in combusted biomass. This study was carried out in the Guinean savanna of Lamto (Côte d’Ivoire) to evaluate fire-mediated carbon and nutrient losses from biomass according to the date of burning. The fire regimes tested consisted of three different burning dates: early (EF), mid (MF), and late (LF) season fires, on nine 0.5 ha plots. Carbon and five elemental nutrients were assessed in the aboveground biomass prior to burning and in ash and unburnt biomass after fires; losses were assessed by subtraction. The proportion of nutrients transferred to the atmosphere varied from 42 % (K) to 98 % (C). The lowest losses were recorded during the EF and the greatest during the MF and LF. Emission of CO2 was relatively greatest during the EF than during the MF and LF (16, 14 and 13 t ha-1 respectively). The proportion of the fine ash fraction (< 1 mm) was the greatest during MF. The highest concentrations of K, P, Ca and Mg occurred in this fraction, most susceptible to losses due to wind and rainfall. The percentage losses of C, N and K were positively correlated with fire maximal temperatureand flame height, explaining the relatively higher losses during MF. Over the long term, the MF applied annually, would lead to important depletion of soil nutrients, particularly N and P, which contributes to the low availability of nutrients in the soils of Lamto savannas.

Two Representations of the Moscow Art Theater Audience

2020 ◽  
Vol 17 (5) ◽  
pp. 462-476
Author(s):  
Alexander A. Ushkarev ◽  
Galina G. Gedovius ◽  
Tatyana V. Petrushina
Keyword(s):  
Online Community ◽  
Modern Art ◽  
Virtual Space ◽  
Demographic Parameters ◽  
Cultural Consumption ◽  
Cultural Activity ◽  
Behavioral Differences ◽  
Technological Revolution ◽  
Definition Of

The technological revolution of recent decades has already brought art to the broadest masses, and the unexpected intervention of the pandemic has significantly accelerated the process of migration of theatrical art to the virtual space, causing the corresponding dynamics of the audience. What is the theater audience in the era of digitalization and the spread of alternative forms of cultural consumption? How does the theater build its relationship with the audience today? In search of answers, we conducted a series of sociological surveys of the Chekhov Moscow Art Theater’s audience — both at the theater’s performances and in the online community of its fans. The purpose of this phase of the study was to answer the fundamental questions: do spectators surveyed in the theater and those surveyed online represent the same audience; what are their main differences; and what are the drivers of their spectator behavior? The article presents the main results of a comparative analysis of two images of the Moscow Art Theatre’s audience based on a number of content parameters by two types of surveys, as well as the results of a regression analysis of the theater attendance. The study resulted in definition of the qualitative and behavioral differences between the theater visitors and the viewers surveyed online, and identification of the factors of theater attendance for both of the represented audience groups. The study made it possible to clarify the role of age and other socio-demographic parameters in cultural activity, as well as the influence of preferred forms of cultural consumption (live contacts or online views) on one’s attitude to art, motivation and spectator behavior. The conclusions of the study, despite the uniqueness of the object, reflect the general patterns of the modern art audience’s dynamics.

Transformation

2018 ◽  
Author(s):  
Karen J. Esler ◽  
Anna L. Jacobsen ◽  
R. Brandon Pratt
Keyword(s):  
Climate Change ◽  
Fire Regimes ◽  
Human Populations ◽  
Land Use Land Cover ◽  
Mountainous Areas ◽  
Drivers Of Change ◽  
Natural Systems ◽  
Natural Landscapes ◽  
Habitat Conversion ◽  
Residential Use

Extensive habitat loss and habitat conversion has occurred across all mediterranean-type climate (MTC) regions, driven by increasing human populations who have converted large tracts of land to production, transport, and residential use (land-use, land-cover change) while simultaneously introducing novel forms of disturbance to natural landscapes. Remaining habitat, often fragmented and in isolated or remote (mountainous) areas, is threatened and degraded by altered fire regimes, introduction of invasive species, nutrient enrichment, and climate change. The types and impacts of these threats vary across MTC regions, but overall these drivers of change show little signs of abatement and many have the potential to interact with MTC region natural systems in complex ways.

scholarly journals Inbreeding of Bottlenecked Butterfly Populations: Estimation Using the Likelihood of Changes in Marker Allele Frequencies

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1053-1063 ◽  
Author(s):  
Ilik J Saccheri ◽  
Ian J Wilson ◽  
Richard A Nichols ◽  
Michael W Bruford ◽  
Paul M Brakefield
Keyword(s):  
Linkage Disequilibrium ◽  
Probability Distribution ◽  
Reproductive Success ◽  
Genetic Markers ◽  
Allele Frequencies ◽  
Demographic Parameters ◽  
Bicyclus Anynana ◽  
Marker Allele ◽  
Wide Applicability ◽  
Per Gene

Abstract Polymorphic enzyme and minisatellite loci were used to estimate the degree of inbreeding in experimentally bottlenecked populations of the butterfly, Bicyclus anynana (Satyridae), three generations after founding events of 2, 6, 20, or 300 individuals, each bottleneck size being replicated at least four times. Heterozygosity fell more than expected, though not significantly so, but this traditional measure of the degree of inbreeding did not make full use of the information from genetic markers. It proved more informative to estimate directly the probability distribution of a measure of inbreeding, σ2, the variance in the number of descendants left per gene. In all bottlenecked lines, σ2 was significantly larger than in control lines (300 founders). We demonstrate that this excess inbreeding was brought about both by an increase in the variance of reproductive success of individuals, but also by another process. We argue that in bottlenecked lines linkage disequilibrium generated by the small number of haplotypes passing through the bottleneck resulted in hitchhiking of particular marker alleles with those haplotypes favored by selection. In control lines, linkage disequilibrium was minimal. Our result, indicating more inbreeding than expected from demographic parameters, contrasts with the findings of previous (Drosophila) experiments in which the decline in observed heterozygosity was slower than expected and attributed to associative overdominance. The different outcomes may both be explained as a consequence of linkage disequilibrium under different regimes of inbreeding. The likelihood-based method to estimate inbreeding should be of wide applicability. It was, for example, able to resolve small differences in σ2 among replicate lines within bottleneck-size treatments, which could be related to the observed variation in reproductive viability.

scholarly journals A reconstruction of the recent fire regimes of Majete Wildlife Reserve, Malawi, using remote sensing

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie
Keyword(s):  
Remote Sensing ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Dry Season ◽  
Annual Rainfall ◽  
Vegetation Types ◽  
Local Evidence ◽  
Hot Dry Season ◽  
Wildlife Reserve

Abstract Background Fire is an important process that shapes the structure and functioning of African savanna ecosystems, and managers of savanna protected areas use fire to achieve ecosystem goals. Developing appropriate fire management policies should be based on an understanding of the determinants, features, and effects of prevailing fire regimes, but this information is rarely available. In this study, we report on the use of remote sensing to develop a spatially explicit dataset on past fire regimes in Majete Wildlife Reserve, Malawi, between 2001 and 2019. Moderate Resolution Imaging Spectroradiometer (MODIS) images were used to evaluate the recent fire regime for two distinct vegetation types in Majete Wildlife Reserve, namely savanna and miombo. Additionally, a comparison was made between MODIS and Visible Infrared Imager Radiometer Suite (VIIRS) images by separately evaluating selected aspects of the fire regime between 2012 and 2019. Results Mean fire return intervals were four and six years for miombo and savanna vegetation, respectively, but the distribution of fire return intervals was skewed, with a large proportion of the area burning annually or biennially, and a smaller proportion experiencing much longer fire return intervals. Variation in inter-annual rainfall also resulted in longer fire return intervals during cycles of below-average rainfall. Fires were concentrated in the hot-dry season despite a management intent to restrict burning to the cool-dry season. Mean fire intensities were generally low, but many individual fires had intensities of 14 to 18 times higher than the mean, especially in the hot-dry season. The VIIRS sensors detected many fires that were overlooked by the MODIS sensors, as images were collected at a finer scale. Conclusions Remote sensing has provided a useful basis for reconstructing the recent fire regime of Majete Wildlife Reserve, and has highlighted a current mismatch between intended fire management goals and actual trends. Managers should re-evaluate fire policies based on our findings, setting clearly defined targets for the different vegetation types and introducing flexibility to accommodate natural variation in rainfall cycles. Local evidence of the links between fires and ecological outcomes will require further research to improve fire planning.

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