Fire severity and prolonged drought do not interact to reduce plant regeneration capacity but alter community composition in a Mediterranean shrubland

Springer Nature 2024-07-24

Background Disturbance-regime shifts are often a manifestation related to climate change. In Mediterranean ecosystems, summer-drought lengthening and high fire-severity may be among the most detrimental processes for plant recovery capacity. However, although isolated effects have been usually assessed, the effects when both disturbances interact are less known. This paper examined the possible interactive impacts of increased fire severity and summer-drought lengthening on Mediterranean vegetation recovery. Our initial hypothesis maintained that both disturbances would interact and cause greater recovery damage than in an isolated way. For this reason, we performed an experimental fire in summer by creating two fire severity levels: control fire severity (CSev) and increased fire severity by adding dry biomass (IncrSev). Following fire, and using rainfall exclusions roofs, we extended summer drought conditions toward the first autumn after fire (AutExcl treatment) and toward the first post-fire spring (SprExcl). All the treatment-levels combinations were replicated in five 0.5 × 0.5 m plots. Results Emerged seedlings were not affected by treatments, but plant establishment was significantly impaired by extended droughts at the end of the first post-fire year, particularly for Cistaceae and subshrubs. Nevertheless, we found no effects of increased fire severity on either isolation or combination with drought. Notwithstanding, the combination of some treatment levels brought about changes in plant composition. These changes were driven mainly by the detrimental effects of treatments on perennial forbs. This functional group was affected by treatments, which suggests that they may be more sensitive to changes in fire severity and severe droughts. Conclusion Increased fire severity might not affect plant recovery either by itself or by interacting with drought because prolonged drought may mask increased fire severity impact on Mediterranean seeding species. However, f
Antecedentes Los cambios en los regímenes de perturbaciones suelen ser una expresión con relación con el cambio climático. En ecosistemas mediterráneos, el alargamiento de la sequía estival y los incendios de alta severidad pueden estar entre los procesos que más negativamente afectan a la capacidad de recuperación de la vegetación. Aunque los efectos aislados han sido usualmente evaluados, los efectos combinados entre sequías prolongadas junto a incendios de alta severidad son menos conocidos. Este trabajo examina los posibles impactos interactivos entre un incremento en la severidad de los incendios y el alargamiento de la sequía estival en la recuperación de la vegetación en ecosistemas mediterráneos. Nuestra hipótesis inicial sostiene que ambas perturbaciones interactúan y causan un mayor daño en la recuperación de la vegetación que si actúan de manera aislada. Por este motivo, realizamos un fuego experimental durante el verano mediante la creación de dos niveles de severidad: uno de control (CSev) y otro de incremento en la severidad del fuego mediante la adición de biomasa seca (IncrSev). Después de la quema experimental, y usando techos de exclusión de lluvia, extendimos las condiciones de sequía hasta el primer otoño tras el fuego experimental (tratamiento de exclusión de otoño: AutExcl) y luego durante la primera primavera tras el fuego experimental (SprExcl). Todas las combinaciones y niveles de tratamientos fueron replicados en parcelas de 0.5 × 0.5 m. Resultados La emergencia de plántulas no se vio afectada por los tratamientos, aunque el establecimiento al primer año tras el fuego fue significativamente perjudicado debido al alargamiento de la sequía estival, en particular para las Cistaceas y los subarbustos. A pesar de ello, no encontramos efectos del incremento de la severidad ni de manera aislada ni en combinación con la sequía extendida. Sin embargo, la combinación de algunos niveles de tratamientos produjo cambios en la composición de la comunidad

Plant community assembly; Disturbance interactions; Disturbance regimes; Compound impacts; Climate change; Summer drought; Plant recovery; info:eu-repo/semantics/article

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ESALI oai:rua.ua.es:10045/145714
Fire Ecology. 2024, 20:61. https://doi.org/10.1186/s42408-024-00292-w
1933-9747
10.1186/s42408-024-00292-w
1452790394

UNIV DE ALICANTE
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