Resilience of Mediterranean communities to fire depends on burn severity and type of ecosystem

Abstract

Background Burn severity plays an important role in shaping vegetation recovery in Mediterranean ecosystems. In the present study, we aimed to evaluate the influence of burn severity on short-term vegetation resilience in different ecosystems. We selected the Cabrera wildfire (northwest Iberian Peninsula), which affected shrubland, heathland, broomland, and oak woodland ecosystems in 2017. Immediately after the fire, we established 249 field plots within the burned area, in which burn severity was quantified by the application of the Composite Burn Index, differentiating three burn severity categories: low, moderate, and high. Moreover, we fixed 136 plots in unburned areas at two different maturity stages: young (unburned for the last 10 years) and old (unburned for the last 20 years) vegetation. Two years after the wildfire, we evaluated the total percentage cover of vegetation in four vertical strata ranging from 0 to > 4 m, as well as the cover of each woody species and total herbaceous vegetation in the lowest stratum (0–0.5 m). Resilience of the 2017 burned areas was interpreted in terms of the difference in vegetation cover and species composition in relation to the two different maturity stages. Results The results showed that the lowest stratum was the most resilient in the short term. In fact, all ecosystems presented high resilience of this stratum in low-severity areas. In shrublands and heathlands, this was mainly the consequence of the regeneration of herbaceous vegetation, as the dominant woody species did not fully recover in any of the burned situations (at least 21% and 11% less cover in shrubland and heathland burned plots compared to areas of young vegetation). Specifically, the resilience of this stratum was higher in broomlands and oak woodlands, mainly under moderate and high severities. In these ecosystems, woody dominant species recovered with respect to young vegetation at the 0–0.5-m level. Despite this, burn severity had a negative impact on the short-term resilience of the uppermost strata in broomlands and oak woodlands (cover values close to 0%). Conclusions The effects of burn severity on short-term vegetation resilience differed among type of ecosystems and vertical strata, so these results may constitute a starting point for the evaluation of the influence of burn severity and vegetation composition and structure on ecosystem resilience.

The Effects of Fire Severity on Vegetation Structural Complexity Assessed Using SAR Data Are Modulated by Plant Community Types in Mediterranean Fire-Prone Ecosystems

“…This behavior was amplified in gorse shrublands, dominated also by facultative seeders, which exhibited a small VSC that did not differ between fire severity scenarios. This can be probably associated with the poor environmental conditions of the sites where gorse communities are established, such as degraded soils with low soil organic carbon and available nutrient contents after the wildfire [122], hindering vegetation recovery responses in the short-term after the fire at the study site [8].…”

“…However, wildfires have been traditionally considered hazards with negative connotations and sometimes socioeconomic disasters because of the associated damage to human assets and even loss of lives [5]. In addition, wildfires may entail large ecological effects on plant communities [6][7][8], soil physicochemical and biological properties [9][10][11][12]), hydrogeological processes [13,14], and wildlife [15,16] in the Mediterranean Basin. This has led to special concerns since Mediterranean terrestrial ecosystems in this region hold a large number of endemisms [17] and are considered a biodiversity hotspot [18].…”

Fire Vulnerability, Resilience, and Recovery Rates of Mediterranean Pine Forests Using a 33-Year Time Series of Satellite Imagery

“…Recovery capacity (VRAF index) depends directly on burn severity [82]. As mentioned by other authors [37,106], slopes play a crucial role in determining recovery capacity due to their relationship with soil erosion.…”

“…The vegetation type significantly influences the ecological vulnerability to forest fires [34,71]. For example, in Mediterranean ecosystems, vegetation has a remarkable ability to recover from disturbances caused by fire [80][81][82]. However, plant species that lack adaptations or tolerance to fire may suffer a high mortality rate, altering the dynamics and composition of the ecosystem [83].…”

Bioactive Compounds for Customized Brain Health: What Are We and Where Should We Be Heading?

“…With the recent advancements in technology and imaging studies, it is becoming more evident that a nutrient-dense diet has a significant impact on brain health as well. The translation of high-resolution studies is documented in epidemiological reports that link low-nutrient-dense diets, such as the Western diet (WD), to mental health ailments and high-quality diets, such as the Mediterranean diet (MD), to mental well-being [1][2][3]. A nutrient-dense diet (ND) typically encompasses a spectrum of naturally colorful and whole food such as legumes, fruits, vegetables, nuts, herbs, spices, and grains.…”