INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
artículos
Título:
Effects of biological legacies and herbivory on fuels and flammability traits: A long-term experimental study of alternative stable states
Autor/es:
VEBLEN, THOMAS T.; GOWDA, JUAN H.; MORALES, JUAN M.; TIRIBELLI, FLORENCIA; RAFFAELE, ESTELA; BLACKHALL, MELISA; GOWDA, JUAN H.; KITZBERGER, THOMAS; TIRIBELLI, FLORENCIA; PARITSIS, JUAN; BLACKHALL, MELISA; KITZBERGER, THOMAS; PARITSIS, JUAN; VEBLEN, THOMAS T.; MORALES, JUAN M.; RAFFAELE, ESTELA
Revista:
JOURNAL OF ECOLOGY (PRINT)
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2017 vol. 105 p. 1309 - 1322
ISSN:
0022-0477
Resumen:
1. Ecological memory, oftendetermined by the extent and type of retained biological legacies presentfollowing disturbance, may produce persistent landscape patterns. However,after fire, the persistence or switch to an alternative state may depend on thecomplex interplay of ecological memory (biological legacies) and potentialeffects of new external factors influencing the post-fire environment. Thecurrent study assesses both the strength of ecological memory resulting frombiological legacies of pre-burn vegetation types as well as post-fire effectsof livestock.2. Following a severe fire in 1999,we set up a network of long-term exclosures to examine the effects of legaciesand cumulative herbivory by cattle on fuel types, amounts, distribution,flammability and micro-environmental conditions in two post-fire communitiesrepresenting alternative fire-driven states: pyrophobic Nothofagus pumiliosubalpine forests and pyrophytic N. antarctica tall shrublands in northwesternPatagonia, Argentina. 3. Our results show that theretained post-disturbance legacies of tall shrublands and subalpine forestslargely determine fuel and flammability traits of the post-fire plantcommunities 16 years after fire. The importance of biological legacies retainedfrom the unburned plant communities was reflected by the substantially higheramounts of total fine fuel, greater vertical and horizontal fuel continuity andthe higher temperatures reached during experimental tissue combustion atpost-fire shrubland compared to post-fire forest sites. 4. We show that herbivores mayproduce antagonistic effects on flammability by decreasing tissue ignitability,total fine fuel and litter depth, and disrupting the vertical and horizontalfine fuel continuity, therefore reducing the probability of fire propagation.However, cattle can increase ratios of dead to live fine fuels, reduce soilmoisture, and inhibit tree height growth to canopy size, consequently impedingthe development of a closed pyrophobic forest canopy.5- Synthesis. Our results supportthe hypothesis that biological legacies, most importantly the dominance bypyrophytic woody plants that resprout vigorously versus the dominance bypyrophobic obligate seeders, favour fuel and flammability characteristics atthe community level which reinforce the mechanisms maintaining pyrophyticshrublands versus pyrophobic forests. Herbivory by introduced cattle canpartially blur sharp pyrophobic/pyrophytic state boundaries by promoting thedevelopment of novel post-fire transitional states.