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Juli G. Pausas 《植被学杂志》1997,8(5):703-706
Abstract. Many Mediterranean species have evolved strategies that allow them to survive periodic wildfires. Quercus suber trees resprout after fire, some from stem buds and others from basal buds only. In the former case the canopy recovers quickly. In the latter case the stem dies but the tree survives and regrows from basal sprouts. The probability of stem death and the degree of height recovery were studied after a fire in a Q. suber forest in NE Spain using logistic regression analysis. The results suggest that most trees survive after fire; the probability of stem death is negatively related to tree diameter; and recovery is positively related to tree diameter and to bark thickness. Implication for management and conservation of cork-oak forests are discussed. 相似文献
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Recurrent wildfires constitute a major selecting force in shaping the structure of plant communities. At the regional scale, fire favours phenotypic and phylogenetic clustering in Mediterranean woody plant communities. Nevertheless, the incidence of fire within a fire-prone region may present strong variations at the local, landscape scale. This study tests the prediction that woody communities on acid, nutrient-poor soils should exhibit more pronounced phenotypic and phylogenetic clustering patterns than woody communities on fertile soils, as a consequence of their higher flammability and, hence, presumably higher propensity to recurrent fire. Results confirm the predictions and show that habitat filtering driven by fire may be detected even in local communities from an already fire-filtered regional flora. They also provide a new perspective from which to consider a preponderant role of fire as a key evolutionary force in acid, infertile Mediterranean heathlands. 相似文献
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Fire as a key driver of Earth's biodiversity 总被引:1,自引:0,他引:1
Tianhua He Byron B. Lamont Juli G. Pausas 《Biological reviews of the Cambridge Philosophical Society》2019,94(6):1983-2010
Many terrestrial ecosystems are fire prone, such that their composition and structure are largely due to their fire regime. Regions subject to regular fire have exceptionally high levels of species richness and endemism, and fire has been proposed as a major driver of their diversity, within the context of climate, resource availability and environmental heterogeneity. However, current fire‐management practices rarely take into account the ecological and evolutionary roles of fire in maintaining biodiversity. Here, we focus on the mechanisms that enable fire to act as a major ecological and evolutionary force that promotes and maintains biodiversity over numerous spatiotemporal scales. From an ecological perspective, the vegetation, topography and local weather conditions during a fire generate a landscape with spatial and temporal variation in fire‐related patches (pyrodiversity), and these produce the biotic and environmental heterogeneity that drives biodiversity across local and regional scales. There have been few empirical tests of the proposition that ‘pyrodiversity begets biodiversity’ but we show that biodiversity should peak at moderately high levels of pyrodiversity. Overall species richness is greatest immediately after fire and declines monotonically over time, with postfire successional pathways dictated by animal habitat preferences and varying lifespans among resident plants. Theory and data support the ‘intermediate disturbance hypothesis’ when mean patch species diversity is correlated with mean fire intervals. Postfire persistence, recruitment and immigration allow species with different life histories to coexist. From an evolutionary perspective, fire drives population turnover and diversification by promoting a wide range of adaptive responses to particular fire regimes. Among 39 comparisons, the number of species in 26 fire‐prone lineages is much higher than that in their non‐fire‐prone sister lineages. Fire and its byproducts may have direct mutagenic effects, producing novel genotypes that can lead to trait innovation and even speciation. A paradigm shift aimed at restoring biodiversity‐maintaining fire regimes across broad landscapes is required among the fire research and management communities. This will require ecologists and other professionals to spread the burgeoning fire‐science knowledge beyond scientific publications to the broader public, politicians and media. 相似文献
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Plant persistence traits in fire-prone ecosystems of the Mediterranean basin: a phylogenetic approach 总被引:9,自引:0,他引:9
The two main fire response traits found in the Mediterranean basin are the resprouting capacity (R) and the propagule-persistence capacity (P). Previous studies suggested that these two traits might be correlated. In this paper we first test whether R and P have evolved independently. Then, we ask if the correlation occurs because (a) one trait is not the target of selection but it is genetically linked to the other trait which is the one under selection pressure (indirect selection), or (b) because different evolutionary responses to the same selective pressure are acting in parallel on populations at different genetic starting points (parallel selection). Finally, we test to what extent resprouting is associated with some vegetative and reproductive traits.
To answer these questions we used a traits database for the eastern Iberian Peninsula and we assembled the phylogenetic tree on the basis of published information. The results indicate that the two traits are negatively associated and support the parallel selection scenario in which changes in R precedes changes in P. The phylogenetic–informed associations of resprouting with other traits (plant height, age at maturity) support the existence of allocation tradeoffs.
The results are consistent with the biogeographical history of the Mediterranean basin flora where most of lineages already resprouted to persist after a disturbance during the Tertiary, thus making it improbable that an additional costly persistence strategy would evolve under the Quaternary climatic conditions. 相似文献
To answer these questions we used a traits database for the eastern Iberian Peninsula and we assembled the phylogenetic tree on the basis of published information. The results indicate that the two traits are negatively associated and support the parallel selection scenario in which changes in R precedes changes in P. The phylogenetic–informed associations of resprouting with other traits (plant height, age at maturity) support the existence of allocation tradeoffs.
The results are consistent with the biogeographical history of the Mediterranean basin flora where most of lineages already resprouted to persist after a disturbance during the Tertiary, thus making it improbable that an additional costly persistence strategy would evolve under the Quaternary climatic conditions. 相似文献
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Vinícius de L. Dantas Juli G. Pausas Marco Antônio Batalha Priscilla de Paula Loiola Marcus Vinicius Cianciaruso 《Oecologia》2013,171(2):487-494
Intraspecific trait variability plays a fundamental role in community structure and dynamics; however, few studies have evaluated its relative importance to the overall response of communities to environmental pressures. Since fire is considered a key factor in Neotropical savannas, we investigated to what extent the functional effects of fire in a Brazilian savanna occurs via intra- or interspecific trait variability. We sampled 12 traits in communities subjected to three fire regimes in the last 12 years: annual, biennial, and protected. To evaluate fire’s relative effects, we fitted a general linear mixed models with species as random and fire as fixed factors, using: (1) all species in the communities (i.e., considering intra- and interspecific variabilities); (2) 18 species common to all fire regimes (i.e., intraspecific variability only); and (3) all species with their overall average trait values (i.e., interspecific variability only). We assessed the relative role of intra- or interspecific variability by comparing the significance of each trait in the three analyses. We also compared the within and between fire variabilities with a variance component analysis. Five traits presented larger intraspecific than interspecific variability, and the main effect of fire occurred at the intraspecific level. These results confirm that it is important to consider intraspecific variability to fully understand fire-prone communities. Moreover, trait variability was larger within than among fire regimes. Thus, fire may act more as an external filter, preventing some of the species from the regional pool from colonizing the cerrado, than as an internal factor structuring the already filtered cerrado communities. 相似文献
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Given the observed heterogeneity in fire severity produced within wildfires, we asked to what extent this heterogeneity might
affect post-fire regeneration. For this purpose, we studied the post-fire dynamics of Pinus halepensis (Aleppo pine) in the eastern Iberian Peninsula. Sampling was stratified on the basis of fire severity. We defined three fire
severity classes based on the degree of consumption of the pine canopy. The results suggested that there is no clear relationship
between seedling density and fire severity; however, mortality was lower and growth (height, shoot biomass and root biomass)
was higher in the high severity class. These results can be explained by soil processes: Sites in the high fire severity class
may have sustained higher fire intensities, resulting in higher soil organic matter mineralisation and higher ash deposition,
and thus in higher post-fire soil fertility. This higher fertility would produce faster growth in pine seedlings. Independent
of the severity class, seedling mortality was higher in quadrats (50 × 50 cm) with higher cover of the perennial grass Brachypodium retusum (Poaceae), suggesting a possible competitive effect. For all plots in all 3 severity classes, spatial analysis suggests an
aggregate seedlings pattern, but with independence from the position of the adult (source) trees.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Ana Hernández-Serrano Miguel Verdú Luís Santos-del-Blanco José Climent Santiago C. González-Martínez Juli G. Pausas 《Annals of botany》2014,114(3):571-577