Wild harvest of Cycas arnhemica (Cycadaceae)

impact on survival, recruitment and growth in Arnhem Land, northern Australia

A GRIFFITHS, H Schult, Julian Gorman

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    An experimental wild harvest of Cycas arnhemica K.D. Hill, an understorey plant in tropical eucalypt savannas, was conducted in central Arnhem Land, Australia. Replicated harvest treatments were monitored over 2 years with tagged individuals. A range of a priori candidate statistical models were compared to determine the effect of wild harvest and environmental factors such as fire frequency and disturbance from feral animals on survival, recruitment and stem growth. The mean density of C. arnhemica was 1630 ha-1 and ranged from 550 to 2250 ha-1. Harvesting intensity in the 0.04-ha quadrats varied between 10 and 32% of all cycad stems (excluding seedlings). There was no clear effect of harvest treatment on stem survival, seedling abundance and stem growth on the remaining C. arnhemica 2 years after the harvest treatments were applied. Survival of woody stems was higher than that of seedlings but there was considerable overlap among the larger size classes. Seedling abundance was generally low and variable across the three sites, and seedlings were entirely absent from quadrats burnt twice during the study period. Stem growth varied considerably across the three sites and was similar between small and large stems. We suggest that the wild harvest of this abundant Cycas species in a remote region of northern Australia will have minimal impact on wild populations if focused on juvenile stems and return time is extended to 15-40 years at harvested locations. Future harvest management of this and other Cycas species in northern Australia will benefit from further research on stochastic population models to determine the most suitable harvest strategies, particularly for smaller Cycas populations. � CSIRO 2005.
    Original languageEnglish
    Pages (from-to)771-779
    Number of pages9
    JournalAustralian Journal of Botany
    Volume53
    Issue number8
    Publication statusPublished - 2005

    Fingerprint

    Cycadaceae
    Cycas
    stem
    stem elongation
    stems
    seedlings
    seedling
    feral animals
    Cycadopsida
    statistical models
    seedling growth
    understory
    savannas
    harvest
    land
    wild population
    environmental factors
    savanna
    environmental factor
    disturbance

    Cite this

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    title = "Wild harvest of Cycas arnhemica (Cycadaceae): impact on survival, recruitment and growth in Arnhem Land, northern Australia",
    abstract = "An experimental wild harvest of Cycas arnhemica K.D. Hill, an understorey plant in tropical eucalypt savannas, was conducted in central Arnhem Land, Australia. Replicated harvest treatments were monitored over 2 years with tagged individuals. A range of a priori candidate statistical models were compared to determine the effect of wild harvest and environmental factors such as fire frequency and disturbance from feral animals on survival, recruitment and stem growth. The mean density of C. arnhemica was 1630 ha-1 and ranged from 550 to 2250 ha-1. Harvesting intensity in the 0.04-ha quadrats varied between 10 and 32{\%} of all cycad stems (excluding seedlings). There was no clear effect of harvest treatment on stem survival, seedling abundance and stem growth on the remaining C. arnhemica 2 years after the harvest treatments were applied. Survival of woody stems was higher than that of seedlings but there was considerable overlap among the larger size classes. Seedling abundance was generally low and variable across the three sites, and seedlings were entirely absent from quadrats burnt twice during the study period. Stem growth varied considerably across the three sites and was similar between small and large stems. We suggest that the wild harvest of this abundant Cycas species in a remote region of northern Australia will have minimal impact on wild populations if focused on juvenile stems and return time is extended to 15-40 years at harvested locations. Future harvest management of this and other Cycas species in northern Australia will benefit from further research on stochastic population models to determine the most suitable harvest strategies, particularly for smaller Cycas populations. � CSIRO 2005.",
    keywords = "growth, harvesting, recruitment, survival, understory, Arnhem Land, Australasia, Australia, Northern Territory, Animalia, Cycadaceae, Cycas",
    author = "A GRIFFITHS and H Schult and Julian Gorman",
    year = "2005",
    language = "English",
    volume = "53",
    pages = "771--779",
    journal = "Australian Journal of Botany",
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    Wild harvest of Cycas arnhemica (Cycadaceae) : impact on survival, recruitment and growth in Arnhem Land, northern Australia. / GRIFFITHS, A; Schult, H; Gorman, Julian.

    In: Australian Journal of Botany, Vol. 53, No. 8, 2005, p. 771-779.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Wild harvest of Cycas arnhemica (Cycadaceae)

    T2 - impact on survival, recruitment and growth in Arnhem Land, northern Australia

    AU - GRIFFITHS, A

    AU - Schult, H

    AU - Gorman, Julian

    PY - 2005

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    N2 - An experimental wild harvest of Cycas arnhemica K.D. Hill, an understorey plant in tropical eucalypt savannas, was conducted in central Arnhem Land, Australia. Replicated harvest treatments were monitored over 2 years with tagged individuals. A range of a priori candidate statistical models were compared to determine the effect of wild harvest and environmental factors such as fire frequency and disturbance from feral animals on survival, recruitment and stem growth. The mean density of C. arnhemica was 1630 ha-1 and ranged from 550 to 2250 ha-1. Harvesting intensity in the 0.04-ha quadrats varied between 10 and 32% of all cycad stems (excluding seedlings). There was no clear effect of harvest treatment on stem survival, seedling abundance and stem growth on the remaining C. arnhemica 2 years after the harvest treatments were applied. Survival of woody stems was higher than that of seedlings but there was considerable overlap among the larger size classes. Seedling abundance was generally low and variable across the three sites, and seedlings were entirely absent from quadrats burnt twice during the study period. Stem growth varied considerably across the three sites and was similar between small and large stems. We suggest that the wild harvest of this abundant Cycas species in a remote region of northern Australia will have minimal impact on wild populations if focused on juvenile stems and return time is extended to 15-40 years at harvested locations. Future harvest management of this and other Cycas species in northern Australia will benefit from further research on stochastic population models to determine the most suitable harvest strategies, particularly for smaller Cycas populations. � CSIRO 2005.

    AB - An experimental wild harvest of Cycas arnhemica K.D. Hill, an understorey plant in tropical eucalypt savannas, was conducted in central Arnhem Land, Australia. Replicated harvest treatments were monitored over 2 years with tagged individuals. A range of a priori candidate statistical models were compared to determine the effect of wild harvest and environmental factors such as fire frequency and disturbance from feral animals on survival, recruitment and stem growth. The mean density of C. arnhemica was 1630 ha-1 and ranged from 550 to 2250 ha-1. Harvesting intensity in the 0.04-ha quadrats varied between 10 and 32% of all cycad stems (excluding seedlings). There was no clear effect of harvest treatment on stem survival, seedling abundance and stem growth on the remaining C. arnhemica 2 years after the harvest treatments were applied. Survival of woody stems was higher than that of seedlings but there was considerable overlap among the larger size classes. Seedling abundance was generally low and variable across the three sites, and seedlings were entirely absent from quadrats burnt twice during the study period. Stem growth varied considerably across the three sites and was similar between small and large stems. We suggest that the wild harvest of this abundant Cycas species in a remote region of northern Australia will have minimal impact on wild populations if focused on juvenile stems and return time is extended to 15-40 years at harvested locations. Future harvest management of this and other Cycas species in northern Australia will benefit from further research on stochastic population models to determine the most suitable harvest strategies, particularly for smaller Cycas populations. � CSIRO 2005.

    KW - growth

    KW - harvesting

    KW - recruitment

    KW - survival

    KW - understory

    KW - Arnhem Land

    KW - Australasia

    KW - Australia

    KW - Northern Territory

    KW - Animalia

    KW - Cycadaceae

    KW - Cycas

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    VL - 53

    SP - 771

    EP - 779

    JO - Australian Journal of Botany

    JF - Australian Journal of Botany

    SN - 0067-1924

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    ER -