Post-fire regeneration in a Mediterranean pine forest with historically low fire frequency

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Constanze Buhk - , Martin Luther University Halle-Wittenberg (Author)
  • Lars Götzenberger - , Helmholtz Centre for Environmental Research (Author)
  • Karsten Wesche - , Martin Luther University Halle-Wittenberg (Author)
  • Pedro Sánchez Gómez - , University of Murcia (Author)
  • Isabell Hensen - , Martin Luther University Halle-Wittenberg (Author)

Abstract

Species of Mediterranean vegetation are known to regenerate directly after fire. The phenomenon of autosuccession (direct regeneration) has been found to be often combined with an increase of species richness during the first years after fire due to the high abundance of short-lived herbaceous plants facilitated by plentiful nutrients and light. The high degree of vegetation resilience, which is expressed in terms of autosuccession, has been explained by the selective pressure of fire in historic times. According to existing palaeoecological data, however, the Pinus halepensis forests in the Ricote Mountains (Province of Murcia, SE Spain) did not experience substantial fire impact before the presence of man nor are they especially fire-prone today. Therefore, we studied post-fire regeneration to find out if direct succession is present or if species from pre-fire vegetation are absent during the post-fire regeneration stages. Patterns of succession were deduced from observations made in sample plots on sites of a known regeneration age as well as in adjacent unburnt areas. The results of the vegetation analyses, including a Detrended Correspondence Analysis, indicate that Pinus halepensis forest regeneration after fire resembles autosuccession. As regards the presence of woody species, there is a high percentage similarity on north (83%) and south (70%) facing slopes during the first year after fire vs. reference areas which is due, for example, to direct regeneration of the resprouting Quercus coccifera or seeders like Pinus halepensis or Fumana laevipes. However, if herbaceous species are included in the comparison, the similarity on north-facing sites decreases (to 53%) with the presence of additional species, mainly ruderals like Anagallis arvensis or Reseda phyteuma, and even woody species on the burnt plots. This effect indicates "enhanced autosuccession", which was not found on south-facing sites where overall species richness was very high irrespective of the impact of fire. Locally we found limited regeneration of some species, for example Pinus halepensis at high altitudes (1000 m), even 22 years after fire. As we assume that historical fires did not play an important role in the area and direct succession is present nevertheless, our results support the theory that autosuccession is not a process restricted to fire-prone areas. Fire has been only one of several selective forces since human settlement that probably led to a set of species pre-adapted against recurrent disturbance.

Details

Original languageEnglish
Pages (from-to)288-298
Number of pages11
JournalActa Oecologica
Volume30
Issue number3
Publication statusPublished - Nov 2006
Peer-reviewedYes
Externally publishedYes

Keywords

Keywords

  • (Auto)succession, DCA, Murcia, PCA, Pinus halepensis, Pre-adaptation, Spain, Species richness, Species similarity