Vegetation dynamics of managed Mediterranean forests 16 yr after large fires in southeastern Spain

Abstract

Abbreviations S = Species richness index; H' = Shannon diversity index; J' = Jaccard index; NMDS = Non-metric multidimensional scaling; GLM = Generalized linear models Nomenclature Flora Ib erica (Castroviejo 1986(Castroviejo -2012; Flora Europaea (Tutin et al. AbstractQuestion: Adaptive forest management requires scientific knowledge about post-fire vegetation dynamics, mainly on initial and transitional stages. We hypothesized that management practices are as important as the timing of the operations themselves, with respect to diversity and species composition of the understorey post-fire regenerated Pinus halepensis forests.Location: Two post-fire regenerated P. halepensis stands burned in 1994 under contrasting climatic conditions (Dry -595 mmÁyr À1 -and Semi-arid -340 mmÁyr À1 -sites) in southeast Spain.Methods: At both sites, we set experimental plots to test early treatments, including removal of the understorey vegetation (scrubbing, at post-fire year 5), thinning (at post-fire years 5 and 10) and control plots. Alpha diversity indices, including species richness, Shannon diversity index and plant cover, as a measure of vegetation abundance, and beta diversity indices, such as Jaccard index and non-metric multidimensional scaling were diachronically analysed at postfire years 5 (before the treatments) and 16.Results: At both sites, the most abundant species were obligate seeders or grass resprouters. Low overlap in the occurrence of species was also found between sites on both dates, but the number of shared species increased by the end of the study period. Significant differences in the diversity indices were detected between sites. Despite the silvicultural treatments, the species richness and Shannon diversity index values at the Dry site were similar in the treated and control plots at 16 yr. Conversely, at the Semi-arid site, the species richness and Shannon diversity index values were enhanced by the thinning treatments carried out 10 yr after the fire. Plant cover increased despite the treatments (scrubbing and thinning) on both the pine and understorey layers in every treated plot.Conclusion: Our forest management trials enhanced the diversity indices when applied to very high tree density post-fire regenerated stands, even applied to areas with very limited resources (nutrients, water, etc.) such as semi-arid ecosystems. Thus, scrubbing at post-fire year 5 plus thinning carried out at post-fire year 10 proved to be a suitable option to reduce fire hazards in the short term at both sites and to enhance plant diversity at the Semi-arid site.

Post-fire recovery of the plant community in Pinus brutia forests: active vs. indirect restoration techniques after salvage logging

“…However, our results supported the second hypothesis -that indirect restoration sites have a more fire-resilient community than active ones. This result also shows that such a shift in the plant community composition can be masked if only species diversity measures are considered (Moya et al 2009, Alfaro-Sánchez et al 2015. The case mentioned above was more dramatic in the plantation treatment in which annual species had approximately 40% more cover than others.…”

Post-fire restoration of pine forests in the Badary area, Tunkinskiy National Park, Russia

“…Often, results are being obtained in the monitoring and assessment of the biocenosis status cast doubt on reliability of the prospects for ongoing demutation processes (Thanos & Doussi, 2000;Eugenio et al, 2006;Ürker et al, 2018;Shinkarenko et al, 2021). One of options for minimising the risk of natural regeneration loss are reforestation activi-ties (Kobechinskaya et al, 2009;Babintseva et al, 2010;Alfaro-Sánchez et al, 2015;Granados et al, 2016;Keane, 2018). In 2016, the Tunkinskiy National Park staff carried out artificial forest planting of 390 000 pine seedling.…”