Density- and distance-dependent seedling survival in a ballistically dispersed subtropical tree species Philenoptera sutherlandii

S Boudreau, Michael Lawes

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species. � 2008 Cambridge University Press.
    Original languageEnglish
    Pages (from-to)1-8
    Number of pages8
    JournalJournal of Tropical Ecology
    Volume24
    Issue number1
    Publication statusPublished - 2008

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    Philenoptera
    seedling
    seedlings
    predator
    predators
    satiety
    seed
    seed dispersal
    seeds
    Fabaceae
    forage
    pods

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    @article{e2342864a73a402c8d2e009e8d19faeb,
    title = "Density- and distance-dependent seedling survival in a ballistically dispersed subtropical tree species Philenoptera sutherlandii",
    abstract = "We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species. � 2008 Cambridge University Press.",
    keywords = "density dependence, dispersal, legume, mortality, recruitment (population dynamics), seed predation, seedling, survival, tropical environment, Africa, KwaZulu-Natal, Ongoye Forest, South Africa, Southern Africa, Sub-Saharan Africa, Fabaceae, Hexapoda, Philenoptera",
    author = "S Boudreau and Michael Lawes",
    year = "2008",
    language = "English",
    volume = "24",
    pages = "1--8",
    journal = "Journal of Tropical Ecology",
    issn = "0266-4674",
    publisher = "Cambridge University Press",
    number = "1",

    }

    Density- and distance-dependent seedling survival in a ballistically dispersed subtropical tree species Philenoptera sutherlandii. / Boudreau, S; Lawes, Michael.

    In: Journal of Tropical Ecology, Vol. 24, No. 1, 2008, p. 1-8.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Density- and distance-dependent seedling survival in a ballistically dispersed subtropical tree species Philenoptera sutherlandii

    AU - Boudreau, S

    AU - Lawes, Michael

    PY - 2008

    Y1 - 2008

    N2 - We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species. � 2008 Cambridge University Press.

    AB - We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species. � 2008 Cambridge University Press.

    KW - density dependence

    KW - dispersal

    KW - legume

    KW - mortality

    KW - recruitment (population dynamics)

    KW - seed predation

    KW - seedling

    KW - survival

    KW - tropical environment

    KW - Africa

    KW - KwaZulu-Natal

    KW - Ongoye Forest

    KW - South Africa

    KW - Southern Africa

    KW - Sub-Saharan Africa

    KW - Fabaceae

    KW - Hexapoda

    KW - Philenoptera

    M3 - Article

    VL - 24

    SP - 1

    EP - 8

    JO - Journal of Tropical Ecology

    JF - Journal of Tropical Ecology

    SN - 0266-4674

    IS - 1

    ER -