Browsing by Subject "Fire"

Now showing 1 - 4 of 4
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    Desarrollo de la vegetación y periodicidad de incendios forestales
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 1986) Samo Lumbreras, A.; Facultad de Biología
    In the Spanish district of VaIencia an average of 15.000 Ha of vegetation are burned out every year. This actually accounts for ca. 4% of the provine's forest resources in spite of the very strong efforts being made in order to both prevent forest fires and lower in size the burned out areas. Under these circumstances, the questions which would normally be made as to the reasons for the no decrese in the affected areas are: Are there insuficient extinguishing means to be blamed for this problem? Are there more o less variable weather conditions prone to bnng about the fires? 1s it that the vegetation of the province (which in fact is the resource destroyed by fire) is exhibiting such a degree of flammability or burnability that renders the catastrophic fires unavoidable? The above are the reasons whch we are planning to look into and consider in detail in order to better understand bosh the forest fire evolution and the factors involved in such a natural element as fire, which in fact is shaping the vegetation of Mediterranean ecosystems.
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    Fire in the Early Palaeolithic: evidence from burnt small mammal bones at Cueva negra del Estrecho del Río Quípar, Murcia, Spain
    (Elsevier, 2016-10) Rhodes, S.E.; Walker, M.J.; López Jiménez, A.; López Martínez, M.; Haber Uriarte, María; Fernández Jalvo, Y.; Chazan, M.; Prehistoria, Arqueología, Historia Antigua, Historia Medieval y Ciencias y Técnicas Historiográficas
    The development of pyrotechnology is a hallmark of human history, providing our ancestors with warmth, security and cooked food. Evidence for fire use before 400 thousand years ago (kya) remains contentious due largely to the taphonomically fragile nature of charcoal and ash. As such, it is imperative to the study of prehistoric fire that we develop techniques and methodologies for identifying anthropogenic fire use via more robust materials. A new methodology described by Fernández-Jalvo and Avery (2015) based on small mammal taphonomy to identify high intensity fire events from the distant past is replicated herein. When we applied this method to assemblages from Cueva Negra del Estrecho del Río Quípar, an upland rock-shelter in southeastern Spain, dated to between 780 kya and 980 kya, we recognized a spatial relationship between highly heat modified micromammal specimens and a previously reported delineated feature of thermally altered and carbonate rich sediment which also includes heat-fractured chert and calcined bone (the fire feature). The proportion of heavily heat-modified specimens (charred and/or calcined specimens) identified within the stratigraphic context associated with the fire feature proved statistically significant (x2 = 169.18, p < 0.001) when compared with the proportion of similarly modified specimens from overlying deposits (within other stratigraphic layers). The degree of discolouration seen on the micromammal remains within the fire feature has been linked to temperatures exceeding 600 °C (Shipman et al., 1984), and as such supports claims that the fire feature may have an anthropogenic origin. Environmental scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) of bone specimens confirms that this discolouration is due to burning rather than post-depositional mineral staining. This confirms that methodology, which represents a novel line of evidence for identifying pyrotechnical events at early Palaeolithic sites, can be used to identify potentially anthropogenic fire events from the distant past when alternative scenarios are excluded. Furthermore, studies of this type showcase the value of including detailed taphonomic studies of microfauna assemblages within multidisciplinary research projects.
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    Population genomics of a reindeer lichen species from North American lichen woodlands
    (Wiley, 2021-01-29) Grewe, Felix; Payette, Serge; Villarreal A., Juan Carlos; Alonso García, Marta; Biología Vegetal
    PREMISE: Lichens are one of the main structural components of plant communities in the North American boreal biome. They play a pivotal role in lichen woodlands, a large ecosystem situated north of the closed-crown forest zone, and south of the forest–tundra zone. In Eastern Canada (Quebec), there is a remnant LW found 500 km south of its usual distribution range, in the Parc National des Grands-Jardins, originated mainly because of wildfires. We inferred the origin of the lichen Cladonia stellaris from this LW and assessed its genetic diversity in a postfire succession. METHODS: We genotyped 122 individuals collected across a latitudinal gradient in Quebec. Using the software Stacks, we compared four different approaches of locus selection and single-nucleotide polymorphism calling. We identified the best fitting approach to investigate population structure and estimate genetic diversity of C. stellaris. RESULTS: Populations in southern Quebec are not genetically different from those of northern LWs. The species consists of at least four phylogenetic lineages with elevated levels of genetic diversity and low co-ancestry. In Parc National des Grands-Jardins, we reported high values of genetic diversity not related with time since fire disturbance and low genetic differentiation among populations with different fire histories. CONCLUSIONS: This first population genomic study of C. stellaris is an important step forward to understand the origin and biogeographic patterns of lichen woodlands in North America. Our findings also contribute to the understanding of the effect of postfire succession on the genetic structure of the species.
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    Postfire regeneration of a thermomediterranean shrubland area in south-eastern Spain
    (Murcia: Universidad de Murcia, Servicio de Publicaciones, 2003) Götzenberger, Lars; Ohl, Constanze; Hensen, Isabell; Sánchez Gómez, Pedro; Sin departamento asociado; Facultad de Biología
    Postfire regeneration of thermomediterranean shrublands burnt in 1998 was studied in the Province of Murcia (SE Spain). The vegetation struc ture of sites with different exposures was compared with that of adja cent unburnt areas. Three years after the fire, the mean vegetation cover of the burnt sites was still significantly lower than that of the non-burnt areas. However, the results of a Detrended Correspondence Analysis indicate that fires induce only minor changes in the species composi tion and the vegetation structure. Fire seems to be a common pheno menon, and the dominant species are characterized by pre-adaptatio ns to withstand fires. The most frequent pre-adaptation is the ability to resprout rapidly from subterranean parts, whereas the regeneration from seeds is clearly less important in the most dominant species.