The existence of a fire-mediated tree-recruitment bottleneck in an Asian savanna

Thuy T. Nguyen, Brett P. Murphy, Patrick J. Baker

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Aim: A considerable proportion of the global savanna biome has been mis-classified as forest, especially in Asia. However, the structure and responses of dominant tree species to fire can help to clarify this ambiguity. Here, we examine demographic structure and fire responses of four dominant tree species in a deciduous dipterocarp forest (DDF) of the continental Southeast Asia. We examine whether fire creates a tree-recruitment bottleneck in the DDF, as in savannas on other continents.

    Location: YokDon National Park, Vietnam.

    Taxon: Dipterocarpus tuberculatus Roxb.; Dipterocarpus obtusifolius Teysm. ex Miq.; Shorea obtusa Wall. ex Blume; Shorea siamensis (Kurz) Miq.

    Methods: We measured the size of all 8,288 individuals of the four dominant dipterocarp species in 12 pair study sites. We then applied fire treatments (burnt or unburnt) to the plots and monitored the survival and growth of juveniles five times over the subsequent growing season.

    Results: All four species showed clear indications of a recruitment bottleneck at the sapling stage. Almost all juveniles in the burnt plots suffered aboveground mortality, but 64% resprouted by the end of the following growing season. Compared to large juveniles, small juveniles had a significantly higher probability of aboveground mortality and a more limited ability to resprout. Within 3 months of fire, 43%–93% of individuals had resprouted, and they had recovered 67%–95% of their pre-fire basal diameter and 43%–94% of their pre-fire height. At the end of the post-fire growing season, burnt juveniles experienced virtually no net increase in size; however, juveniles in unburnt plots attained up to 150% of their pre-fire size.

    Main conclusions: The four dominant tree species of the DDF show remarkable similarities in the demographic structures and fire-responses with savanna tree species on other continents. Our results are consistent with the notion that the DDF is functionally similar to savannas on other continents. Fire appears to act as potent environmental filter of tree species composition in the DDF.

    Original languageEnglish
    Pages (from-to)745-756
    Number of pages12
    JournalJournal of Biogeography
    Volume46
    Issue number4
    Early online date20 Feb 2019
    DOIs
    Publication statusPublished - Apr 2019

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    savanna
    savannas
    Dipterocarpaceae
    deciduous forest
    Dipterocarpus
    growing season
    Shorea obtusa
    demographic statistics
    Tuberculatus
    Shorea
    mortality
    sapling
    biome
    saplings
    South East Asia
    Vietnam
    national parks
    national park
    filter
    species diversity

    Cite this

    @article{f943a837d2f1487bbb74d7f5d9dba2b0,
    title = "The existence of a fire-mediated tree-recruitment bottleneck in an Asian savanna",
    abstract = "Aim: A considerable proportion of the global savanna biome has been mis-classified as forest, especially in Asia. However, the structure and responses of dominant tree species to fire can help to clarify this ambiguity. Here, we examine demographic structure and fire responses of four dominant tree species in a deciduous dipterocarp forest (DDF) of the continental Southeast Asia. We examine whether fire creates a tree-recruitment bottleneck in the DDF, as in savannas on other continents. Location: YokDon National Park, Vietnam. Taxon: Dipterocarpus tuberculatus Roxb.; Dipterocarpus obtusifolius Teysm. ex Miq.; Shorea obtusa Wall. ex Blume; Shorea siamensis (Kurz) Miq. Methods: We measured the size of all 8,288 individuals of the four dominant dipterocarp species in 12 pair study sites. We then applied fire treatments (burnt or unburnt) to the plots and monitored the survival and growth of juveniles five times over the subsequent growing season. Results: All four species showed clear indications of a recruitment bottleneck at the sapling stage. Almost all juveniles in the burnt plots suffered aboveground mortality, but 64{\%} resprouted by the end of the following growing season. Compared to large juveniles, small juveniles had a significantly higher probability of aboveground mortality and a more limited ability to resprout. Within 3 months of fire, 43{\%}–93{\%} of individuals had resprouted, and they had recovered 67{\%}–95{\%} of their pre-fire basal diameter and 43{\%}–94{\%} of their pre-fire height. At the end of the post-fire growing season, burnt juveniles experienced virtually no net increase in size; however, juveniles in unburnt plots attained up to 150{\%} of their pre-fire size. Main conclusions: The four dominant tree species of the DDF show remarkable similarities in the demographic structures and fire-responses with savanna tree species on other continents. Our results are consistent with the notion that the DDF is functionally similar to savannas on other continents. Fire appears to act as potent environmental filter of tree species composition in the DDF.",
    keywords = "deciduous dipterocarp forest, fire, mesic savanna, resprouting, seedling growth, seedling mortality, tree demography, tropical dry forest, YokDon National Park",
    author = "Nguyen, {Thuy T.} and Murphy, {Brett P.} and Baker, {Patrick J.}",
    year = "2019",
    month = "4",
    doi = "10.1111/jbi.13518",
    language = "English",
    volume = "46",
    pages = "745--756",
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    publisher = "Wiley-Blackwell",
    number = "4",

    }

    The existence of a fire-mediated tree-recruitment bottleneck in an Asian savanna. / Nguyen, Thuy T.; Murphy, Brett P.; Baker, Patrick J.

    In: Journal of Biogeography, Vol. 46, No. 4, 04.2019, p. 745-756.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - The existence of a fire-mediated tree-recruitment bottleneck in an Asian savanna

    AU - Nguyen, Thuy T.

    AU - Murphy, Brett P.

    AU - Baker, Patrick J.

    PY - 2019/4

    Y1 - 2019/4

    N2 - Aim: A considerable proportion of the global savanna biome has been mis-classified as forest, especially in Asia. However, the structure and responses of dominant tree species to fire can help to clarify this ambiguity. Here, we examine demographic structure and fire responses of four dominant tree species in a deciduous dipterocarp forest (DDF) of the continental Southeast Asia. We examine whether fire creates a tree-recruitment bottleneck in the DDF, as in savannas on other continents. Location: YokDon National Park, Vietnam. Taxon: Dipterocarpus tuberculatus Roxb.; Dipterocarpus obtusifolius Teysm. ex Miq.; Shorea obtusa Wall. ex Blume; Shorea siamensis (Kurz) Miq. Methods: We measured the size of all 8,288 individuals of the four dominant dipterocarp species in 12 pair study sites. We then applied fire treatments (burnt or unburnt) to the plots and monitored the survival and growth of juveniles five times over the subsequent growing season. Results: All four species showed clear indications of a recruitment bottleneck at the sapling stage. Almost all juveniles in the burnt plots suffered aboveground mortality, but 64% resprouted by the end of the following growing season. Compared to large juveniles, small juveniles had a significantly higher probability of aboveground mortality and a more limited ability to resprout. Within 3 months of fire, 43%–93% of individuals had resprouted, and they had recovered 67%–95% of their pre-fire basal diameter and 43%–94% of their pre-fire height. At the end of the post-fire growing season, burnt juveniles experienced virtually no net increase in size; however, juveniles in unburnt plots attained up to 150% of their pre-fire size. Main conclusions: The four dominant tree species of the DDF show remarkable similarities in the demographic structures and fire-responses with savanna tree species on other continents. Our results are consistent with the notion that the DDF is functionally similar to savannas on other continents. Fire appears to act as potent environmental filter of tree species composition in the DDF.

    AB - Aim: A considerable proportion of the global savanna biome has been mis-classified as forest, especially in Asia. However, the structure and responses of dominant tree species to fire can help to clarify this ambiguity. Here, we examine demographic structure and fire responses of four dominant tree species in a deciduous dipterocarp forest (DDF) of the continental Southeast Asia. We examine whether fire creates a tree-recruitment bottleneck in the DDF, as in savannas on other continents. Location: YokDon National Park, Vietnam. Taxon: Dipterocarpus tuberculatus Roxb.; Dipterocarpus obtusifolius Teysm. ex Miq.; Shorea obtusa Wall. ex Blume; Shorea siamensis (Kurz) Miq. Methods: We measured the size of all 8,288 individuals of the four dominant dipterocarp species in 12 pair study sites. We then applied fire treatments (burnt or unburnt) to the plots and monitored the survival and growth of juveniles five times over the subsequent growing season. Results: All four species showed clear indications of a recruitment bottleneck at the sapling stage. Almost all juveniles in the burnt plots suffered aboveground mortality, but 64% resprouted by the end of the following growing season. Compared to large juveniles, small juveniles had a significantly higher probability of aboveground mortality and a more limited ability to resprout. Within 3 months of fire, 43%–93% of individuals had resprouted, and they had recovered 67%–95% of their pre-fire basal diameter and 43%–94% of their pre-fire height. At the end of the post-fire growing season, burnt juveniles experienced virtually no net increase in size; however, juveniles in unburnt plots attained up to 150% of their pre-fire size. Main conclusions: The four dominant tree species of the DDF show remarkable similarities in the demographic structures and fire-responses with savanna tree species on other continents. Our results are consistent with the notion that the DDF is functionally similar to savannas on other continents. Fire appears to act as potent environmental filter of tree species composition in the DDF.

    KW - deciduous dipterocarp forest

    KW - fire

    KW - mesic savanna

    KW - resprouting

    KW - seedling growth

    KW - seedling mortality

    KW - tree demography

    KW - tropical dry forest

    KW - YokDon National Park

    UR - http://www.scopus.com/inward/record.url?scp=85061769820&partnerID=8YFLogxK

    U2 - 10.1111/jbi.13518

    DO - 10.1111/jbi.13518

    M3 - Article

    VL - 46

    SP - 745

    EP - 756

    JO - Journal of Biogeography

    JF - Journal of Biogeography

    SN - 0305-0270

    IS - 4

    ER -